PIC18F2331 [MICROCHIP]
28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High Performance PWM and A/D; 28 /40/ 44引脚增强型闪存微控制器采用纳瓦技术，高性能PWM和A / D
| 型号： | PIC18F2331 |
| 厂家： | 
MICROCHIP |
| 描述： | 28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High Performance PWM and A/D |
| 文件： | 总396页 (文件大小：3661K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
PIC18F2331/2431/4331/4431
Data Sheet
28/40/44-Pin Enhanced
Flash Microcontrollers
with nanoWatt Technology,
High Performance PWM and A/D
2003 Microchip Technology Inc.
Preliminary
DS39616B
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is intended through suggestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical
components in life support systems is not authorized except
with express written approval by Microchip. No licenses are
conveyed, implicitly or otherwise, under any intellectual
property rights.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, KEELOQ, MPLAB, PIC, PICmicro, PICSTART,
PRO MATE and PowerSmart are registered trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
AmpLab, FilterLab, microID, MXDEV, MXLAB, PICMASTER,
SEEVAL, SmartShunt and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A.
Application Maestro, dsPICDEM, dsPICDEM.net,
dsPICworks, ECAN, ECONOMONITOR, FanSense,
FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP,
ICEPIC, microPort, Migratable Memory, MPASM, MPLIB,
MPLINK, MPSIM, PICkit, PICDEM, PICDEM.net, PICtail,
PowerCal, PowerInfo, PowerMate, PowerTool, rfLAB, rfPIC,
Select Mode, SmartSensor, SmartTel and Total Endurance
are trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip Technology Incorporated in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2003, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received ISO/TS-16949:2002 quality system certification for
its worldwide headquarters, design and wafer fabrication facilities in
Chandler and Tempe, Arizona and Mountain View, California in October
2003 . The Company’s quality system processes and procedures are
for its PICmicro® 8-bit MCUs, KEELOQ® code hopping devices, Serial
EEPROMs, microperipherals, non-volatile memory and analog
products. In addition, Microchip’s quality system for the design and
manufacture of development systems is ISO 9001:2000 certified.
DS39616B-page ii
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
28/40/44-Pin Enhanced Flash Microcontrollers with
nanoWatt Technology, High Performance PWM and A/D
14-bit Power Control PWM Module:
Power-Managed Modes:
• Up to 4 channels with complementary outputs
• Edge- or center-aligned operation
• Flexible dead-band generator
• Run
• Idle
CPU on, peripherals on
CPU off, peripherals on
• Sleep CPU off, peripherals off
• Hardware fault protection inputs
• Simultaneous update of duty cycle and period:
- Flexible special event trigger output
• Idle mode currents down to 5.8 µA typical
• Sleep current down to 0.1 µA typical
• Timer1 oscillator, 1.8 µA typical, 32 kHz, 2V
• Watchdog Timer (WDT), 2.1 µA typical
• Two-Speed oscillator start-up
Motion Feedback Module:
• Three independent input capture channels:
Peripheral Highlights:
• High current sink/source 25 mA/25 mA
• Three external interrupts
• Two Capture/Compare/PWM (CCP) modules:
- Capture is 16-bit, max. resolution 6.25 ns (TCY/16)
- Compare is 16-bit, max. resolution 100 ns (TCY)
- PWM output: PWM resolution is 1 to 10 bits
• Enhanced USART module:
- Supports RS-485, RS-232 and LIN 1.2
- Auto-Wake-up on Start bit
- Auto-Baud detect
• RS-232 operation using internal oscillator block
(no external crystal required)
- Flexible operating modes for period and pulse
width measurement
- Special Hall Sensor interface module
- Special event trigger output to other modules
• Quadrature Encoder Interface:
- 2 phase inputs and one index input from encoder
- High and low position tracking with direction
status and change of direction interrupt
- Velocity measurement
High-Speed, 200 Ksps 10-bit A/D Converter:
• Up to 9 channels
• Simultaneous two-channel sampling
• Sequential sampling: 1, 2 or 4 selected channels
• Auto-conversion capability
Special Microcontroller Features:
• 4-word FIFO with selectable interrupt frequency
• Selectable external conversion triggers
• Programmable acquisition time
• 100,000 erase/write cycle enhanced Flash
program memory typical
• 1,000,000 erase/write cycle data EEPROM
memory typical
Flexible Oscillator Structure:
• Four crystal modes up to 40 MHz
• Flash/data EEPROM retention: 100 years
• Self-programmable under software control
• Priority levels for interrupts
• 8 X 8 Single-cycle Hardware Multiplier
• Extended Watchdog Timer (WDT):
- Programmable period from 41 ms to 131s
• Two external clock modes up to 40 MHz
• Internal oscillator block:
- 8 user selectable frequencies: 31 kHz to 8 MHz
- OSCTUNE can compensate for frequency drift
• Secondary oscillator using Timer1 @ 32 kHz
• Fail-Safe Clock Monitor:
• Single-supply In-Circuit Serial Programming™
(ICSP™) via two pins
• In-Circuit Debug (ICD) via two pins
- Allows for safe shutdown of device if clock fails
- Drives PWM outputs safely when debugging
Program Memory
Data Memory
SSP
10-bit
A/D CCP
(ch)
14-bit
PWM
(ch)
Timers
8/16-bit
Device
I/O
EUSART
Flash # Single-Word SRAM EEPROM
(bytes) Instructions (bytes) (bytes)
Slave
SPI
2
I C™
PIC18F2331 8192
PIC18F2431 16384
PIC18F4331 8192
PIC18F4431 16384
4096
8192
4096
8192
768
768
768
768
256
256
256
256
24
24
36
36
5
5
9
9
2
2
2
2
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
6
6
8
8
1/3
1/3
1/3
1/3
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 1
PIC18F2331/2431/4331/4431
Pin Diagrams
28-Pin SDIP, SOIC
• 1
2
28
27
26
25
24
RB7/KBI3/PGD
RB6/KBI2/PGC
RB5/KBI1/PWM4/PGM
RB4/KBI0/PWM5
RB3/PWM3
MCLR/VPP/RE3
RA0/AN0
(1)
3
RA1/AN1
4
RA2/AN2/VREF-/CAP1/INDX
RA3/AN3/VREF+/CAP2/QEA
RA4/AN4/CAP3/QEB
AVDD
5
RB2/PWM2
6
7
8
23
22
21
RB1/PWM1
RB0/PWM0
AVSS
VDD
OSC1/CLKI/RA7
OSC2/CLKO/RA6
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2/FLTA
RC2/CCP1/FLTB
RC3/T0CKI/T5CKI/INT0
9
20
19
18
17
16
15
VSS
10
11
12
13
14
RC7/RX/DT/SDO
RC6/TX/CK/SS
RC5/INT2/SCK/SCL
RC4/INT1/SDI/SDA
Note 1: Low-voltage programming must be enabled.
40-Pin PDIP
MCLR/VPP/RE3
RA0/AN0
1
2
3
4
5
6
7
8
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
RB7/KBI3/PGD
RB6/KBI2/PGC
RB5/KBI1/PWM4/PGM
RB4/KBI0/PWM5
RB3/PWM3
(2)
RA1/AN1
RA2/AN2/VREF-/CAP1/INDX
RA3/AN3/VREF+/CAP2/QEA
RA4/AN4/CAP3/QEB
RB2/PWM2
RA5/AN5/LVDIN
RE0/AN6
RB1/PWM1
RB0/PWM0
VDD
RE1/AN7
RE2/AN8
9
10
11
12
13
14
15
16
17
18
19
20
VSS
AVDD
AVSS
RD7/PWM7
RD6/PWM6
(4)
OSC1/CLKI/RA7
OSC2/CLKO/RA6
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2/FLTA
RC2/CCP1/FLTB
RD5/PWM4
(3)
RD4/FLTA
(1)
RC7/RX/DT/SDO
RC6/TX/CK/SS
(1)
(1)
RC5/INT2/SCK /SCL
(1)
(1)
(1)
(1)
RC3/T0CKI /T5CKI /INT0
RD0/T0CKI/T5CKI
RD1/SDO
RC4/INT1/SDI /SDA
RD3/SCK/SCL
RD2/SDI/SDA
Note 1: RC3 is the alternate pin for T0CKI/T5CKI; RC4 is the alternate pin for SDI/SDA; RC5 is the alternate pin
for SCK/SCL.
2: Low-voltage programming must be enabled.
3: RD4 is the alternate pin for FLTA.
4: RD5 is the alternate pin for PWM4.
DS39616B-page 2
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
Pin Diagrams (Continued)
44-Pin TQFP
RC7/RX/DT/SDO(1)
RD4/FLTA(3)
RD5/PWM4(4)
RD6/PWM6
RD7/PWM7
VSS
NC
33
32
31
30
29
28
27
26
25
24
23
1
2
3
4
5
6
7
8
9
RC0/T1OSO/T1CKI
OSC2/CLKO/RA6
OSC1/CLKI/RA7
AVSS
AVDD
RE2/AN8
RE1/AN7
RE0/AN6
RA5/AN5/LVDIN
RA4/AN4/CAP3/QEB
PIC18F4331
PIC18F4431
VDD
RB0/PWM0
RB1/PWM1
RB2/PWM2
RB3/PWM3
10
11
Note 1: RC3 is the alternate pin for T0CKI/T5CKI; RC4 is the alternate pin for SDI/SDA; RC5 is the alternate pin
for SCK/SCL.
2: Low-voltage programming must be enabled.
3: RD4 is the alternate pin for FLTA.
4: RD5 is the alternate pin for PWM4.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 3
PIC18F2331/2431/4331/4431
Pin Diagrams (Continued)
44-Pin QFN
RC7/RX/DT/SDO(1)
RD4/FLTA(3)
RD5/PWM4(4)
RD6/PWM6
RD7/PWM7
VSS
1
2
3
4
5
6
7
8
9
OSC2/CLKO/RA6
OSC1/CLKI/RA7
VSS
33
32
31
30
29
28
27
26
AVSS
PIC18F4331
PIC18F4431
AVDD
VDD
RE2/AN8
RE1/AN7
RE0/AN6
RA5/AN5/LVDIN
RA4/AN4/CAP3/QEB
VDD
AVDD
RB0/PWM0
RB1/PWM1
RB2/PWM2
25
24
23
10
11
Note 1: RC3 is the alternate pin for T0CKI/T5CKI; RC4 is the alternate pin for SDI/SDA; RC5 is the alternate pin
for SCK/SCL.
2: Low-voltage programming must be enabled.
3: RD4 is the alternate pin for FLTA.
4: RD5 is the alternate pin for PWM4.
DS39616B-page 4
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 7
2.0 Oscillator Configurations ............................................................................................................................................................ 21
3.0 Power-Managed Modes ............................................................................................................................................................. 31
4.0 Reset.......................................................................................................................................................................................... 45
5.0 Memory Organization................................................................................................................................................................. 57
6.0 Flash Program Memory.............................................................................................................................................................. 75
7.0 Data EEPROM Memory ............................................................................................................................................................. 85
8.0 8 X 8 Hardware Multiplier........................................................................................................................................................... 89
9.0 Interrupts .................................................................................................................................................................................... 91
10.0 I/O Ports ................................................................................................................................................................................... 107
11.0 Timer0 Module ......................................................................................................................................................................... 133
12.0 Timer1 Module ......................................................................................................................................................................... 137
13.0 Timer2 Module ......................................................................................................................................................................... 143
14.0 Timer5 Module ......................................................................................................................................................................... 145
15.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 151
16.0 Motion Feedback Module......................................................................................................................................................... 159
17.0 Power Control PWM Module.................................................................................................................................................... 181
18.0 Synchronous Serial Port (SSP) Module ................................................................................................................................... 211
19.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART)............................................................... 221
20.0 10-bit High-Speed Analog-to-Digital Converter (A/D) Module.................................................................................................. 243
21.0 Low-Voltage Detect.................................................................................................................................................................. 261
22.0 Special Features of the CPU.................................................................................................................................................... 267
23.0 Instruction Set Summary.......................................................................................................................................................... 287
24.0 Development Support............................................................................................................................................................... 331
25.0 Electrical Characteristics.......................................................................................................................................................... 337
26.0 Preliminary DC and AC Characteristics Graphs and Tables.................................................................................................... 371
27.0 Packaging Information.............................................................................................................................................................. 373
Appendix A: Revision History............................................................................................................................................................. 379
Appendix B: Device Differences ........................................................................................................................................................ 379
Appendix C: Conversion Considerations ........................................................................................................................................... 380
Appendix D: Migration from Baseline to Enhanced Devices.............................................................................................................. 380
Appendix E: Migration from Mid-range to Enhanced Devices ........................................................................................................... 381
Appendix F: Migration from High-end to Enhanced Devices ............................................................................................................. 381
INDEX................................................................................................................................................................................................ 383
On-Line Support................................................................................................................................................................................. 391
Systems Information and Upgrade Hot Line ...................................................................................................................................... 391
Reader Response.............................................................................................................................................................................. 392
PIC18F2331/2431/4331/4431 Product Identification System ............................................................................................................ 393
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 5
PIC18F2331/2431/4331/4431
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DS39616B-page 6
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
• On-the-fly Mode Switching: The power-man-
aged modes are invoked by user code during
operation, allowing the user to incorporate power
saving ideas into their application’s software
design.
1.0
DEVICE OVERVIEW
This document contains device specific information for
the following devices:
• PIC18F2331
• PIC18F2431
• PIC18F4331
• PIC18F4431
• Lower Consumption in Key Modules: The
power requirements for both Timer1 and the
Watchdog Timer have been reduced by up to
80%, with typical values of 1.1 and 2.1 µA,
respectively.
This family offers the advantages of all PIC18 micro-
controllers – namely, high computational performance
at an economical price, with the addition of high endur-
ance enhanced Flash program memory and a high-
speed 10-bit A/D converter. On top of these features,
the PIC18F2331/2431/4331/4431 family introduces
design enhancements that make these microcontrol-
lers a logical choice for many high performance, power
control and motor control applications. These special
peripherals include:
1.1.2
MULTIPLE OSCILLATOR OPTIONS
AND FEATURES
All of the devices in the PIC18F2331/2431/4331/4431
family offer nine different oscillator options, allowing
users a wide range of choices in developing application
hardware. These include:
• 14-bit resolution Power Control PWM Module
(PCPWM) with programmable dead time insertion
• Four crystal modes, using crystals or ceramic
resonators.
• Motion Feedback Module (MFM), including a
3-channel Input Capture (IC) Module and
Quadrature Encoder Interface (QEI)
• Two external clock modes, offering the option of
using two pins (oscillator input and a divide-by-4
clock output) or one pin (oscillator input, with the
second pin reassigned as general I/O).
• High-speed 10-bit A/D Converter (HSADC)
The PCPWM can generate up to eight complementary
PWM outputs with dead-band time insertion. Overdrive
current is detected by off-chip analog comparators or
the digital fault inputs (FLTA, FLTB).
• Two external RC oscillator modes, with the same
pin options as the external clock modes.
• An internal oscillator block, which provides an
8 MHz clock and an INTRC source (approxi-
mately 31 kHz, stable over temperature and VDD),
as well as a range of 6 user-selectable clock fre-
quencies (from 125 kHz to 4 MHz) for a total of 8
clock frequencies.
The MFM Quadrature Encoder Interface provides
precise rotor position feedback and/or velocity
measurement. The MFM 3 X input capture or external
interrupts can be used to detect the rotor state for
electrically commutated motor applications using Hall
Sensor feedback, such as BLDC motor drives.
Besides its availability as a clock source, the internal
oscillator block provides a stable reference source that
gives the family additional features for robust
operation:
PIC18F2331/2431/4331/4431 devices also feature
Flash program memory and an internal RC oscillator
with built-in LP modes.
• Fail-Safe Clock Monitor: This option constantly
monitors the main clock source against a
reference signal provided by the internal
oscillator. If a clock failure occurs, the controller is
switched to the internal oscillator block, allowing
for continued low speed operation or a safe
application shutdown.
1.1
New Core Features
1.1.1
nanoWatt TECHNOLOGY
All of the devices in the PIC18F2331/2431/4331/4431
family incorporate a range of features that can signifi-
cantly reduce power consumption during operation.
Key items include:
• Two-Speed Start-up: This option allows the
internal oscillator to serve as the clock source
from Power-on Reset or wake-up from Sleep
mode, until the primary clock source is available.
This allows for code execution during what would
otherwise be the clock start-up interval, and can
even allow an application to perform routine
background activities and return to Sleep without
returning to full power operation.
• Alternate Run Modes: By clocking the controller
from the Timer1 source or the internal oscillator
block, power consumption during code execution
can be reduced by as much as 90%.
• Multiple Idle Modes: The controller can also run
with its CPU core disabled, but the peripherals are
still active. In these states, power consumption
can be reduced even further, to as little as 4% of
normal operation requirements.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 7
PIC18F2331/2431/4331/4431
• High-speed 10-bit A/D Converter: This module
incorporates Programmable Acquisition Time,
allowing for a channel to be selected and a
conversion to be initiated without waiting for a
sampling period and thus, reducing code
overhead.
1.2
Other Special Features
• Memory Endurance: The enhanced Flash cells
for both program memory and data EEPROM are
rated to last for many thousands of erase/write
cycles – up to 100,000 for program memory and
1,000,000 for EEPROM. Data retention without
refresh is conservatively estimated to be greater
than 100 years.
• Motion Feedback Module (MFM): This module
features a Quadrature Encoder Interface (QEI)
and an Input Capture (IC) module. The QEI
accepts two phase inputs (QEA, QEB) and one
index input (INDX) from an incremental encoder.
The QEI supports high and low precision position
tracking, direction status and change of direction
interrupt, and velocity measurement. The input
capture features 3 channels of independent input
capture with Timer5 as the time base, a special
event trigger to other modules, and an adjustable
noise filter on each IC input.
• Self-programmability: These devices can write
to their own program memory spaces under inter-
nal software control. By using a bootloader routine
located in the protected Boot Block at the top of
program memory, it becomes possible to create
an application that can update itself in the field.
• Power Control PWM Module: In PWM mode,
this module provides 1, 2 or 4 modulated outputs
for controlling half-bridge and full-bridge drivers.
Other features include Auto-Shutdown on fault
detection and Auto-Restart to reactivate outputs
once the condition has cleared.
• Extended Watchdog Timer (WDT): This
enhanced version incorporates a 16-bit prescaler,
allowing a time-out range from 4 ms to over 2
minutes, that is stable across operating voltage
and temperature.
• Enhanced USART: This serial communication
module is capable of standard RS-232 operation
using the internal oscillator block, removing the
need for an external crystal (and its accompany-
ing power requirement) in applications that talk to
the outside world. This module also includes auto-
baud detect and LIN capability.
DS39616B-page 8
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
The devices are differentiated from each other in three
ways:
1.3
Details on Individual Family
Members
1. Flash program memory (8 Kbytes for
Devices in the PIC18F2331/2431/4331/4431 family are
available in 28-pin (PIC18F2X31) and 40/44-pin
(PIC18F4X31) packages. The block diagram for the
two groups is shown in Figure 1-1.
PIC18F2X31
devices,
16 Kbytes
for
PIC18F4X31).
2. A/D channels (5 for PIC18F2X31 devices, 9 for
PIC18F4X31 devices).
3. I/O ports (3 bidirectional ports on PIC18F2X31
devices, 5 bidirectional ports on PIC18F4X31
devices).
All other features for devices in this family are identical.
These are summarized in Table 1-1.
The pinouts for all devices are listed in Table 1-2 and
Table 1-3.
TABLE 1-1:
DEVICE FEATURES
Features
PIC18F2331
PIC18F2431
PIC18F4331
PIC18F4431
Operating Frequency
DC – 40 MHz
DC – 40 MHz
DC – 40 MHz
DC – 40 MHz
16384
8192
Program Memory (Bytes)
Program Memory (Instructions)
Data Memory (Bytes)
Data EEPROM Memory (Bytes)
Interrupt Sources
8192
16384
8192
4096
768
256
34
4096
8192
768
768
768
256
256
256
22
22
34
I/O Ports
Ports A, B, C
Ports A, B, C
Ports A, B, C, D, E Ports A, B, C, D, E
Timers
4
4
4
4
Capture/Compare/PWM modules
14-bit Power Control PWM
2
2
2
2
(6 Channels)
(6 Channels)
(8 Channels)
(8 Channels)
Motion Feedback module
(Input Capture/Quadrature Encoder
Interface)
1 QEI
or
3x IC
1 QEI
or
3x IC
1 QEI
or
3x IC
1 QEI
or
3x IC
Serial Communications
SSP,
SSP,
SSP,
SSP,
Enhanced USART Enhanced USART Enhanced USART Enhanced USART
10-bit High-Speed
Analog-to-Digital Converter module
5 Input Channels 5 Input Channels 9 Input Channels 9 Input Channels
Resets (and Delays)
POR, BOR,
POR, BOR,
POR, BOR,
POR, BOR,
RESETInstruction, RESETInstruction, RESETInstruction, RESETInstruction,
Stack Full,
Stack Underflow
(PWRT, OST),
Stack Full,
Stack Underflow
(PWRT, OST),
Stack Full,
Stack Underflow
(PWRT, OST),
Stack Full,
Stack Underflow
(PWRT, OST),
MCLR (optional), MCLR (optional), MCLR (optional), MCLR (optional),
WDT
WDT
WDT
WDT
Programmable Low-voltage Detect
Programmable Brown-out Reset
Instruction Set
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
75 Instructions
75 Instructions
75 Instructions
75 Instructions
Packages
40-pin DIP
44-pin TQFP
44-pin QFN
40-pin DIP
44-pin TQFP
44-pin QFN
28-pin SDIP
28-pin SOIC
28-pin SDIP
28-pin SOIC
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 9
PIC18F2331/2431/4331/4431
FIGURE 1-1:
PIC18F2331/2431 BLOCK DIAGRAM
Data Bus<8>
PORTA
PORTB
PORTC
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CAP1/INDX
RA3/AN3/VREF+/CAP2/QEA
RA4/AN4/CAP3/QEB
OSC2/CLKO/RA6
Table Pointer<21>
inc/dec logic
Data Latch
Data RAM
21
8
8
(768 bytes)
21
21
Address Latch
12
OSC1/CLKI/RA7
20
PCLATU PCLATH
Address Latch
Program Memory
Address<12>
PCU PCH PCL
Program Counter
4
12
4
RB0/PWM0
RB1/PWM1
RB2/PWM2
RB3/PWM3
RB4/KBI0/PWM5
RB5/KBI1/PWM4/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
Data Latch
BSR
Bank0, F
FSR0
FSR1
FSR2
31 Level Stack
12
16
inc/dec
logic
Decode
TABLELATCH
8
ROMLATCH
IR
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2/FLTA
RC2/CCP1/FLTB
RC3/T0CKI/T5CKI/INT0
RC4/INT1/SDI/SDA
RC5/INT2/SCK/SCL
RC6/TX/CK/SS
8
Instruction
Decode &
Control
RC7/RX/DT/SDO
PRODH PRODL
8 x 8 Multiply
3
Power-up
Timer
OSC2/CLKO
OSC1/CLKI
T1OSI
8
Timing
W
8
BITOP
8
Oscillator
Start-up Timer
Generation
8
Power-on
Reset
8
T1OSO
4X PLL
ALU<8>
Watchdog
Timer
8
Precision
Band Gap
Reference
Brown-out
Reset
PORTE
Power
Managed
Mode Logic
MCLR/VPP
INTRC
OSC
MCLR/VPP/RE3(1, 2)
VDD, VSS
Timer0
AVDD, AVSS
HS 10-bit
ADC
Timer1
Timer2
Timer5
Synchronous
Serial Port
CCP1
CCP2
EUSART
Data EE
PCPWM
MFM
Note 1: RE3 input pin is only enabled when MCLRE fuse is programmed to ‘0’.
2: RE3 is available only when MCLR is disabled.
DS39616B-page 10
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 1-2:
PIC18F4331/4431 BLOCK DIAGRAM
Data Bus<8>
PORTA
PORTB
PORTC
RA0/AN0
RA1/AN1
Table Pointer<21>
inc/dec logic
Data Latch
21
RA2/AN2/VREF-/CAP1/INDX
RA3/AN3/VREF+/CAP2/QEA
RA4/AN4/CAP3/QEB
RA5/AN5/LVDIN
OSC2/CLKO/RA6
OSC1/CLKI/RA7
8
8
Data RAM
(768 bytes)
21
21
Address Latch
12
20
PCLATU PCLATH
Address Latch
Program Memory
Address<12>
PCU PCH PCL
Program Counter
4
12
4
RB0/PWM0
RB1/PWM1
RB2/PWM2
RB3/PWM3
RB4/KBI0/PWM5
RB5/KBI1/PWM4/PGM(4)
RB6/KBI2/PGC
RB7/KBI3/PGD
Data Latch
BSR
Bank0, F
FSR0
FSR1
FSR2
31 Level Stack
12
16
inc/dec
logic
Decode
TABLELATCH
8
ROMLATCH
IR
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2/FLTA(2)
RC2/CCP1/FLTB
RC3/T0CKI/T5CKI/INT0(3)
RC4/INT1/SDI/SDA(3)
8
RC5/INT2/SCK/SCL(3)
RC6/TX/CK/SS
Instruction
Decode &
Control
RC7/RX/DT/SDO*
PRODH PRODL
8 x 8 Multiply
3
Power-up
Timer
OSC2/CLKO
OSC1/CLKI
T1OSI
8
PORTD
RD0/IT0CKI/T5CKI
RD1/SDO
Timing
Generation
W
8
BITOP
8
Oscillator
Start-up Timer
8
RD2/SDI/SDA
RD3/SCK/SCL
RD4/FLTA(2)
RD5/PWM4(4)
RD6/PWM6
Power-on
Reset
8
T1OSO
4X PLL
ALU<8>
Watchdog
Timer
RD7/PWM7
8
Precision
Band Gap
Reference
Brown-out
Reset
PORTE
Power
Managed
RE0/AN6
MCLR/VPP
Mode Logic
RE1/AN7
RE2/AN8
INTRC
OSC
MCLR/VPP/RE3(1)
VDD, VSS
Timer0
AVDD, AVSS
HS 10-bit
ADC
Timer1
Timer2
Timer5
Synchronous
Serial Port
CCP1
CCP2
EUSART
Data EE
PCPWM
MFM
Note 1: RE3 is available only when MCLR is disabled.
2: RD4 is the alternate pin for FLTA.
3: RC3, RC4 and RC5 are alternate pins for T0CKI/T5CKI, SDI/SDA, SCK/SCL
respectively.
4: RD5 is the alternate pin for PWM4.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 11
PIC18F2331/2431/4331/4431
TABLE 1-2:
PIC18F2331/2431 PINOUT I/O DESCRIPTIONS
Pin
Pin Buffer
Number
Pin Name
Description
Type Type
DIP SOIC
MCLR/VPP/RE3
MCLR
1
9
1
9
Master Clear (input) or programming voltage (input).
Master Clear (Reset) input. This pin is an active-low
Reset to the device.
I
ST
ST
VPP
RE3
P
I
High-voltage ICSP programming enable pin.
Digital input. Available only when MCLR is disabled.
OSC1/CLKI/RA7
OSC1
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode, CMOS otherwise.
External clock source input. Always associated with pin
function OSC1. (See related OSC1/CLKI, OSC2/CLKO
pins.)
I
I
ST
CLKI
CMOS
RA7
I/O
TTL
General purpose I/O pin.
OSC2/CLKO/RA6
OSC2
10
10
Oscillator crystal or clock output.
O
O
—
—
Oscillator crystal output. Connects to crystal or resonator
in Crystal Oscillator mode.
In RC mode, OSC2 pin outputs CLKO, which has 1/4 the
frequency of OSC1 and denotes the instruction cycle rate.
General purpose I/O pin.
CLKO
RA6
I/O
TTL
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
2
3
4
2
3
4
I/O
I
TTL
Analog
Digital I/O.
Analog input 0.
AN0
RA1/AN1
RA1
I/O
I
TTL
Analog
Digital I/O.
Analog input 1.
AN1
RA2/AN2/VREF-/CAP1/INDX
RA2
AN2
VREF-
CAP1
INDX
I/O
TTL
Analog
Analog
ST
Digital I/O.
Analog input 2.
A/D Reference Voltage (Low) input.
Input capture pin 1.
Quadrature Encoder Interface index input pin.
I
I
I
I
ST
RA3/AN3/VREF+/CAP2/QEA
5
6
5
6
RA3
AN3
VREF+
CAP2
QEA
I/O
TTL
Analog
Analog
ST
Digital I/O.
Analog input 3.
A/D Reference Voltage (High) input.
Input capture pin 2.
Quadrature Encoder Interface channel A input pin.
I
I
I
I
ST
RA4/AN4/CAP3/QEB
RA4
AN4
CAP3
QEB
I/O
TTL
Analog
ST
Digital I/O.
Analog input 4.
Input capture pin 3.
Quadrature Encoder Interface channel B input pin.
I
I
I
ST
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
O
= Schmitt Trigger input with CMOS levels
= Output
I
P
= Input
= Power
OD = Open-Drain (no diode to VDD)
DS39616B-page 12
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 1-2:
PIC18F2331/2431 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin
Number
Pin Buffer
Type Type
Pin Name
Description
DIP SOIC
PORTB is a bidirectional I/O port. PORTB can be software
programmed for internal weak pull-ups on all inputs.
RB0/PWM0
RB0
21
22
23
24
25
21
22
23
24
25
I/O
O
TTL
TTL
Digital I/O.
PWM output 0.
PWM0
RB1/PWM1
RB1
I/O
O
TTL
TTL
Digital I/O.
PWM output 1.
PWM1
RB2/PWM2
RB2
I/O
O
TTL
TTL
Digital I/O.
PWM output 2.
PWM2
RB3/PWM3
RB3
I/O
O
TTL
TTL
Digital I/O.
PWM output 3.
PWM3
RB4/KBI0/PWM5
RB4
I/O
I
O
TTL
TTL
TTL
Digital I/O.
Interrupt-on-change pin.
PWM output 5.
KBI0
PWM5
RB5/KBI1/PWM4/PGM
26
26
RB5
I/O
I
O
TTL
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
PWM output 4.
KBI1
PWM4
PGM
I/O
Low-voltage ICSP programming entry pin.
RB6/KBI2/PGC
RB6
27
28
27
28
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming clock pin.
KBI2
PGC
RB7/KBI3/PGD
RB7
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming data pin.
KBI3
PGD
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
O
= Schmitt Trigger input with CMOS levels
= Output
I
P
= Input
= Power
OD = Open-Drain (no diode to VDD)
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 13
PIC18F2331/2431/4331/4431
TABLE 1-2:
PIC18F2331/2431 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin
Pin Buffer
Number
Pin Name
Description
Type Type
DIP SOIC
PORTC is a bidirectional I/O port.
RC0/T1OSO/T1CKI
RC0
11
12
11
12
I/O
O
I
ST
—
ST
Digital I/O.
Timer1 oscillator output.
Timer1 external clock input.
T1OSO
T1CKI
RC1/T1OSI/CCP2/FLTA
RC1
I/O
ST
CMOS
ST
Digital I/O.
Timer1 oscillator input.
Capture2 input, Compare2 output, PWM2 output.
Fault interrupt input pin.
T1OSI
CCP2
FLTA
I
I/O
I
ST
RC2/CCP1/FLTB
RC2
13
14
13
14
I/O
I/O
I
ST
ST
ST
Digital I/O.
CCP1
FLTB
Capture1 input/Compare1 output/PWM1 output.
Fault interrupt input pin,.
RC3/T0CKI/T5CKI/INT0
RC3
I/O
ST
ST
ST
ST
Digital I/O.
T0CKI
T5CKI
INT0
I
I
I
Timer0 alternate clock input.
Timer5 alternate clock input.
External interrupt 0.
RC4/INT1/SDI/SDA
15
16
17
18
15
16
17
18
RC4
INT1
SDI
I/O
I
I
ST
ST
ST
ST
Digital I/O.
External interrupt 1.
SPI™ data in.
I2C™ data I/O.
SDA
I/O
RC5/INT2/SCK/SCL
RC5
INT2
SCK
SCL
I/O
I
I/O
I/O
ST
ST
ST
ST
Digital I/O.
External interrupt 2.
Synchronous serial clock input/output for SPI mode.
Synchronous serial clock input/output for I2C mode.
RC6/TX/CK/SS
RC6
TX
CK
SS
I/O
O
I/O
I
ST
—
ST
TTL
Digital I/O.
USART Asynchronous Transmit.
USART Synchronous Clock (see related RX/DT).
SPI Slave Select input.
RC7/RX/DT/SDO
RC7
RX
DT
I/O
I
I/O
O
ST
ST
ST
—
Digital I/O.
USART Asynchronous Receive.
USART Synchronous Data (see related TX/CK).
SPI data out.
SDO
VSS
VDD
8, 19 8, 19
7, 20 7, 20
P
P
—
—
Ground reference for logic and I/O pins.
Positive supply for logic and I/O pins.
CMOS = CMOS compatible input or output
Legend: TTL = TTL compatible input
ST
O
= Schmitt Trigger input with CMOS levels
= Output
I
P
= Input
= Power
OD = Open-Drain (no diode to VDD)
DS39616B-page 14
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 1-3:
Pin Name
PIC18F4331/4431 PINOUT I/O DESCRIPTIONS
Pin Number
Pin Buffer
Type Type
Description
DIP TQFP QFN
MCLR/VPP/RE3
MCLR
1
18
18
Master Clear (input) or programming voltage (input).
Master Clear (Reset) input. This pin is an active-low.
Reset to the device.
I
ST
ST
VPP
RE3
P
I
Programming voltage input.
Digital input. Available only when MCLR is disabled.
OSC1/CLKI/RA7
OSC1
13
30
32
Oscillator crystal or external clock input.
I
I
ST
CMOS
TTL
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode, CMOS otherwise.
External clock source input. Always associated with pin
function OSC1. (See related OSC1/CLKI, OSC2/CLKO pins.)
General purpose I/O pin.
CLKI
RA7
I/O
OSC2/CLKO/RA6
OSC2
14
31
33
Oscillator crystal or clock output.
O
O
—
—
Oscillator crystal output. Connects to crystal or resonator
in Crystal Oscillator mode.
In RC mode, OSC2 pin outputs CLKO, which has 1/4 the
frequency of OSC1 and denotes the instruction cycle rate.
General purpose I/O pin.
CLKO
RA6
I/O
TTL
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
2
3
4
19
20
21
19
20
21
I/O
I
TTL
Analog
Digital I/O.
Analog input 0.
AN0
RA1/AN1
RA1
I/O
I
TTL
Analog
Digital I/O.
Analog input 1.
AN1
RA2/AN2/VREF-/CAP1/
INDX
RA2
I/O
TTL
Analog
Analog
ST
Digital I/O.
Analog input 2.
A/D Reference Voltage (Low) input.
Input capture pin 1.
Quadrature Encoder Interface index input pin.
AN2
I
I
I
I
VREF-
CAP1
INDX
ST
RA3/AN3/VREF+/
CAP2/QEA
RA3
5
22
22
I/O
TTL
Analog
Analog
ST
Digital I/O.
Analog input 3.
A/D Reference Voltage (High) input.
Input capture pin 2.
Quadrature Encoder Interface channel A input pin.
AN3
VREF+
CAP2
QEA
I
I
I
I
ST
RA4/AN4/CAP3/QEB
6
7
23
24
23
24
RA4
AN4
CAP3
QEB
I/O
TTL
Analog
ST
Digital I/O.
Analog input 4.
Input capture pin 3.
Quadrature Encoder Interface channel B input pin.
I
I
I
ST
RA5/AN5/LVDIN
RA5
I/O
TTL
Digital I/O.
AN5
LVDIN
I
I
Analog
Analog
Analog input 5.
Low-voltage Detect input.
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
O
= Schmitt Trigger input with CMOS levels
= Output
I
P
= Input
= Power
OD = Open-Drain (no diode to VDD)
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 15
PIC18F2331/2431/4331/4431
TABLE 1-3:
Pin Name
PIC18F4331/4431 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Buffer
Type Type
Description
DIP TQFP QFN
PORTB is a bidirectional I/O port. PORTB can be software
programmed for internal weak pull-ups on all inputs.
RB0/PWM0
RB0
33
34
35
36
37
8
9
I/O
O
TTL
TTL
Digital I/O.
PWM output 0.
PWM0
RB1/PWM1
RB1
9
10
11
12
14
I/O
O
TTL
TTL
Digital I/O.
PWM output 1.
PWM1
RB2/PWM2
RB2
10
11
14
I/O
O
TTL
TTL
Digital I/O.
PWM output 2.
PWM2
RB3/PWM3
RB3
I/O
O
TTL
TTL
Digital I/O.
PWM output 3.
PWM3
RB4/KBI0/PWM5
RB4
I/O
I
O
TTL
TTL
TTL
Digital I/O.
Interrupt-on-change pin.
PWM output 5.
KBI0
PWM5
RB5/KBI1/PWM4/
PGM
38
15
15
RB5
KBI1
PWM4
PGM
I/O
I
O
TTL
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
PWM output 4.
I/O
Low-voltage ICSP programming entry pin.
RB6/KBI2/PGC
RB6
39
40
16
17
16
17
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming clock pin.
KBI2
PGC
RB7/KBI3/PGD
RB7
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming data pin.
KBI3
PGD
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
O
= Schmitt Trigger input with CMOS levels
= Output
I
P
= Input
= Power
OD = Open-Drain (no diode to VDD)
DS39616B-page 16
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 1-3:
Pin Name
PIC18F4331/4431 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Buffer
Type Type
Description
DIP TQFP QFN
PORTC is a bidirectional I/O port.
RC0/T1OSO/T1CKI
RC0
15
16
32
35
34
35
I/O
O
I
ST
—
ST
Digital I/O.
Timer1 oscillator output.
Timer1 external clock input.
T1OSO
T1CKI
RC1/T1OSI/CCP2/
FLTA
RC1
I/O
ST
CMOS
ST
Digital I/O.
Timer1 oscillator input.
Capture2 input, Compare2 output, PWM2 output.
Fault interrupt input pin.
T1OSI
CCP2
FLTA
I
I/O
I
ST
RC2/CCP1/FLTB
RC2
17
18
36
37
36
37
I/O
I/O
I
ST
ST
ST
Digital I/O.
CCP1
FLTB
Capture1 input/Compare1 output/PWM1 output.
Fault interrupt input pin.
RC3/T0CKI/T5CKI/
INT0
RC3
I/O
ST
ST
ST
ST
Digital I/O.
T0CKI
T5CKI
INT0
I
I
I
Timer0 alternate clock input.
Timer5 alternate clock input.
External interrupt 0.
RC4/INT1/SDI/SDA
23
24
25
26
42
43
44
1
42
43
44
1
RC4
INT1
SDI
I/O
I
I
ST
ST
ST
ST
Digital I/O.
External interrupt 1.
SPI Data in.
SDA
I/O
I2C Data I/O.
RC5/INT2/SCK/SCL
RC5
INT2
SCK
SCL
I/O
I
I/O
I/O
ST
ST
ST
ST
Digital I/O.
External interrupt 2.
Synchronous serial clock input/output for SPI mode.
Synchronous serial clock input/output for I2C mode.
RC6/TX/CK/SS
RC6
TX
CK
SS
I/O
O
I/O
I
ST
—
ST
ST
Digital I/O.
USART Asynchronous Transmit.
USART Synchronous Clock (see related RX/DT).
SPI Slave Select input.
RC7/RX/DT/SDO
RC7
RX
DT
I/O
I
I/O
O
ST
ST
ST
—
Digital I/O.
USART Asynchronous Receive.
USART Synchronous Data (see related TX/CK).
SPI Data out.
SDO
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
O
= Schmitt Trigger input with CMOS levels
= Output
I
P
= Input
= Power
OD = Open-Drain (no diode to VDD)
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 17
PIC18F2331/2431/4331/4431
TABLE 1-3:
Pin Name
PIC18F4331/4431 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Buffer
Type Type
Description
DIP TQFP QFN
PORTD is a bidirectional I/O port, or a Parallel Slave Port
(PSP) for interfacing to a microprocessor port. These pins
have TTL input buffers when PSP module is enabled.
RD0/T0CKI/T5CKI
RD0
19
38
38
I/O
I
I
ST
ST
ST
Digital I/O.
Timer0 external clock input.
Timer5 input clock.
T0CKI
T5CKI
RD1/SDO
RD1
20
21
39
40
39
40
I/O
O
ST
—
Digital I/O.
SPI Data out.
SDO
RD2/SDI/SDA
RD2
I/O
I
I/O
ST
ST
ST
Digital I/O.
SDI
SDA
SPI Data in.
I2C Data I/O.
RD3/SCK/SCL
RD3
22
41
41
I/O
I/O
I/O
ST
ST
ST
Digital I/O.
SCK
SCL
Synchronous serial clock input/output for SPI mode.
Synchronous serial clock input/output for I2C mode.
RD4/FLTA
RD4
27
28
29
30
2
3
4
5
2
3
4
5
I/O
I
ST
ST
Digital I/O.
Fault interrupt input pin.
FLTA
RD5/PWM4
RD5
I/O
O
ST
TTL
Digital I/O.
PWM output 4.
PWM4
RD6/PWM6
RD6
I/O
O
ST
TTL
Digital I/O.
PWM output 6.
PWM6
RD7/PWM7
RD7
I/O
O
ST
TTL
Digital I/O.
PWM output 7.
PWM7
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
O
= Schmitt Trigger input with CMOS levels
= Output
I
P
= Input
= Power
OD = Open-Drain (no diode to VDD)
DS39616B-page 18
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 1-3:
Pin Name
PIC18F4331/4431 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Buffer
Type Type
Description
DIP TQFP QFN
PORTE is a bidirectional I/O port.
RE0/AN6
RE0
8
9
25
26
27
25
26
27
I/O
I
ST
Analog
Digital I/O.
Analog input 6.
AN6
RE1/AN7
RE1
I/O
I
ST
Analog
Digital I/O.
Analog input 7.
AN7
RE2/AN8
RE2
10
I/O
I
ST
Analog
Digital I/O.
Analog input 8.
AN8
VSS
VDD
12, 6, 29 6, 30,
31 31
P
—
Ground reference for logic and I/O pins.
11, 32 7, 28 7, 8,
P
—
Positive supply for logic and I/O pins.
28,
29
NC
—
12,
13,
13
NC
NC No connect
33, 34
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
O
= Schmitt Trigger input with CMOS levels
= Output
I
P
= Input
= Power
OD = Open-Drain (no diode to VDD)
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 19
PIC18F2331/2431/4331/4431
NOTES:
DS39616B-page 20
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 2-1:
CRYSTAL/CERAMIC
RESONATOROPERATION
(XT, LP, HS OR HSPLL
CONFIGURATION)
2.0
2.1
OSCILLATOR
CONFIGURATIONS
Oscillator Types
(1)
C1
OSC1
The PIC18F2331/2431/4331/4431 devices can be
operated in 10 different oscillator modes. The user can
program the configuration bits FOSC3:FOSC0 in Config-
uration register 1H to select one of these 10 modes:
To
Internal
Logic
(3)
RF
XTAL
1. LP
Low-power Crystal
Sleep
(2)
RS
2. XT
Crystal/Resonator
(1)
PIC18FXXXX
C2
OSC2
3. HS
High-speed Crystal/Resonator
4. HSPLL
High-speed Crystal/Resonator
with PLL enabled
Note 1: See Table 2-1 and Table 2-2 for initial values of
C1 and C2.
5. RC
External Resistor/Capacitor with
FOSC/4 output on RA6
2: A series resistor (RS) may be required for AT
strip cut crystals.
6. RCIO
7. INTIO1
8. INTIO2
External Resistor/Capacitor with
I/O on RA6
3: RF varies with the oscillator mode chosen.
Internal Oscillator with FOSC/4
output on RA6 and I/O on RA7
TABLE 2-1:
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
Internal Oscillator with I/O on RA6
and RA7
Typical Capacitor Values Used:
9. EC
External Clock with FOSC/4 output
External Clock with I/O on RA6
Mode
Freq
OSC1
OSC2
10. ECIO
XT
455 kHz
2.0 MHz
4.0 MHz
56 pF
47 pF
33 pF
56 pF
47 pF
33 pF
2.2
Crystal Oscillator/Ceramic
Resonators
HS
8.0 MHz
16.0 MHz
27 pF
22 pF
27 pF
22 pF
In XT, LP, HS or HSPLL oscillator modes, a crystal or
ceramic resonator is connected to the OSC1 and
OSC2 pins to establish oscillation. Figure 2-1 shows
the pin connections.
Capacitor values are for design guidance only.
These capacitors were tested with the resonators
listed below for basic start-up and operation. These
values are not optimized.
The oscillator design requires the use of a parallel cut
crystal.
Different capacitor values may be required to produce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
VDD and temperature range for the application.
Note:
Use of a series cut crystal may give a
frequency out of the crystal
manufacturers’ specifications.
See the notes on page 22 for additional information.
Resonators Used:
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
16.0 MHz
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 21
PIC18F2331/2431/4331/4431
An external clock source may also be connected to the
OSC1 pin in the HS mode, as shown in Figure 2-2.
TABLE 2-2:
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
Typical Capacitor Values
FIGURE 2-2:
EXTERNAL CLOCK INPUT
OPERATION (HS OSC
CONFIGURATION)
Crystal
Freq
Tested:
Osc Type
C1
C2
LP
XT
HS
32 kHz
200 kHz
1 MHz
4 MHz
4 MHz
8 MHz
20 MHz
33 pF
15 pF
33 pF
27 pF
27 pF
22 pF
15 pF
33 pF
15 pF
33 pF
27 pF
27 pF
22 pF
15 pF
OSC1
Clock from
Ext. System
PIC18FXXXX
(HS Mode)
OSC2
Open
Capacitor values are for design guidance only.
2.3
HSPLL
These capacitors were tested with the crystals listed
below for basic start-up and operation. These values
are not optimized.
A Phase Locked Loop (PLL) circuit is provided as an
option for users who wish to use a lower frequency
crystal oscillator circuit, or to clock the device up to its
highest rated frequency from a crystal oscillator. This
may be useful for customers who are concerned with
EMI due to high-frequency crystals.
Different capacitor values may be required to produce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
VDD and temperature range for the application.
The HSPLL mode makes use of the HS mode oscillator
for frequencies up to 10 MHz. A PLL then multiplies the
oscillator output frequency by 4 to produce an internal
clock frequency up to 40 MHz.
See the notes following this table for additional
information.
Crystals Used:
The PLL is enabled only when the oscillator configura-
tion bits are programmed for HSPLL mode. If
programmed for any other mode, the PLL is not
enabled.
32 kHz
200 kHz
1 MHz
4 MHz
8 MHz
20 MHz
FIGURE 2-3:
PLL BLOCK DIAGRAM
Note 1: Higher capacitance increases the stability
of oscillator, but also increases the start-
up time.
HS Osc Enable
PLL Enable
2: When operating below 3V VDD, or when
using certain ceramic resonators at any
voltage, it may be necessary to use the
HS mode or switch to a crystal oscillator.
(from Configuration Register 1H)
OSC2
OSC1
Phase
Comparator
HS Mode
Crystal
Osc
FIN
3: Since each resonator/crystal has its own
characteristics, the user should consult
the resonator/crystal manufacturer for
FOUT
Loop
Filter
appropriate
components.
values
of
external
4: Rs may be required to avoid overdriving
crystals with low drive level specification.
÷4
VCO
SYSCLK
5: Always verify oscillator performance over
the VDD and temperature range that is
expected for the application.
DS39616B-page 22
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
2.4
External Clock Input
2.5
RC Oscillator
The EC and ECIO oscillator modes require an external
clock source to be connected to the OSC1 pin. There is
no oscillator start-up time required after a Power-on
Reset or after an exit from Sleep mode.
For timing insensitive applications, the “RC” and
“RCIO” device options offer additional cost savings.
The RC oscillator frequency is a function of the supply
voltage, the resistor (REXT) and capacitor (CEXT)
values and the operating temperature. In addition to
this, the oscillator frequency will vary from unit to unit
due to normal manufacturing variation. Furthermore,
the difference in lead frame capacitance between
package types will also affect the oscillation frequency,
especially for low CEXT values. The user also needs to
take into account variation due to tolerance of external
R and C components used. Figure 2-6 shows how the
R/C combination is connected.
In the EC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic. Figure 2-4 shows the pin connections for the EC
Oscillator mode.
FIGURE 2-4:
EXTERNAL CLOCK INPUT
OPERATION
(EC CONFIGURATION)
In the RC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic.
OSC1/CLKI
Clock from
Ext. System
PIC18FXXXX
OSC2/CLKO
FOSC/4
FIGURE 2-6:
RC OSCILLATOR MODE
VDD
The ECIO Oscillator mode functions like the EC mode,
except that the OSC2 pin becomes an additional
general purpose I/O pin. The I/O pin becomes bit 6 of
PORTA (RA6). Figure 2-5 shows the pin connections
for the ECIO Oscillator mode.
REXT
Internal
OSC1
Clock
CEXT
VSS
PIC18FXXXX
FIGURE 2-5:
EXTERNAL CLOCK INPUT
OPERATION
(ECIO CONFIGURATION)
OSC2/CLKO
FOSC/4
Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ
CEXT > 20 pF
OSC1/CLKI
PIC18FXXXX
I/O (OSC2)
Clock from
Ext. System
The RCIO Oscillator mode (Figure 2-7) functions like
the RC mode, except that the OSC2 pin becomes an
additional general purpose I/O pin. The I/O pin
becomes bit 6 of PORTA (RA6).
RA6
FIGURE 2-7:
RCIO OSCILLATOR MODE
VDD
REXT
Internal
OSC1
Clock
CEXT
PIC18FXXXX
VSS
I/O (OSC2)
RA6
Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ
CEXT > 20 pF
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 23
PIC18F2331/2431/4331/4431
2.6.2
INTRC OUTPUT FREQUENCY
2.6
Internal Oscillator Block
The internal oscillator block is calibrated at the factory
to produce an INTOSC output frequency of 8.0 MHz.
This changes the frequency of the INTRC source from
its nominal 31.25 kHz. Peripherals and features that
depend on the INTRC source will be affected by this
shift in frequency.
The PIC18F2331/2431/4331/4431 devices include an
internal oscillator block, which generates two different
clock signals; either can be used as the system’s clock
source. This can eliminate the need for external
oscillator circuits on the OSC1 and/or OSC2 pins.
The main output (INTOSC) is an 8 MHz clock source,
which can be used to directly drive the system clock. It
also drives a postscaler, which can provide a range of
clock frequencies from 125 kHz to 4 MHz. The
INTOSC output is enabled when a system clock
frequency from 125 kHz to 8 MHz is selected.
2.6.3
OSCTUNE REGISTER
The internal oscillator’s output has been calibrated at
the factory, but can be adjusted in the user's applica-
tion. This is done by writing to the OSCTUNE register
(Register 2-1). The tuning sensitivity is constant
throughout the tuning range.
The other clock source is the internal RC oscillator
(INTRC), which provides a 31 kHz output. The INTRC
oscillator is enabled by selecting the internal oscillator
block as the system clock source, or when any of the
following are enabled:
When the OSCTUNE register is modified, the INTOSC
and INTRC frequencies will begin shifting to the new
frequency. The INTRC clock will reach the new fre-
quency within 8 clock cycles (approximately
8 * 32 µs = 256 µs). The INTOSC clock will stabilize
within 1 ms. Code execution continues during this shift.
There is no indication that the shift has occurred. Oper-
ation of features that depend on the INTRC clock
source frequency, such as the WDT, Fail-Safe Clock
Monitor and peripherals, will also be affected by the
change in frequency.
• Power-up Timer
• Fail-Safe Clock Monitor
• Watchdog Timer
• Two-Speed Start-up
These features are discussed in greater detail in
Section 22.0 “Special Features of the CPU”.
The clock source frequency (INTOSC direct, INTRC
direct or INTOSC postscaler) is selected by configuring
the IRCF bits of the OSCCON register (Register 2-2).
2.6.1
INTIO MODES
Using the internal oscillator as the clock source can
eliminate the need for up to two external oscillator pins,
which can then be used for digital I/O. Two distinct
configurations are available:
• In INTIO1 mode, the OSC2 pin outputs FOSC/4,
while OSC1 functions as RA7 for digital input and
output.
• In INTIO2 mode, OSC1 functions as RA7 and
OSC2 functions as RA6, both for digital input and
output.
DS39616B-page 24
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
REGISTER 2-1:
OSCTUNE: OSCILLATOR TUNING REGISTER
U-0
—
U-0
—
R/W-0
TUN5
R/W-0
TUN4
R/W-0
TUN3
R/W-0
TUN2
R/W-0
TUN1
R/W-0
TUN0
bit 7
bit 0
bit 7, 6
bit 5-0
Unimplemented: Read as ‘0’
TUN<5:0>: Frequency Tuning bits
011111= Maximum frequency
•
•
•
•
000001
000000= Center frequency. Oscillator module is running at the calibrated frequency.
111111
•
•
•
•
100000= Minimum frequency
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
‘1’ = Bit is set
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 25
PIC18F2331/2431/4331/4431
2.7.1
OSCILLATOR CONTROL REGISTER
2.7
Clock Sources and Oscillator
Switching
The OSCCON register (Register 2-2) controls several
aspects of the system clock’s operation, both in full
power operation and in power-managed modes.
Like previous PIC18 devices, the PIC18F2331/2431/
4331/4431 devices include a feature that allows the
system clock source to be switched from the main
oscillator to an alternate low frequency clock source.
PIC18F2331/2431/4331/4431 devices offer two alter-
nate clock sources. When enabled, these give addi-
tional options for switching to the various power-
managed operating modes.
The System Clock Select bits, SCS1:SCS0, select the
clock source that is used when the device is operating
in power-managed modes. The available clock sources
are the primary clock (defined in Configuration register
1H), the secondary clock (Timer1 oscillator) and the
internal oscillator block. The clock selection has no
effect until a SLEEP instruction is executed and the
device enters a power-managed mode of operation.
The SCS bits are cleared on all forms of Reset.
Essentially, there are three clock sources for these
devices:
• Primary oscillators
The Internal Oscillator Select bits, IRCF2:IRCF0, select
the frequency output of the internal oscillator block that
is used to drive the system clock. The choices are the
INTRC source, the INTOSC source (8 MHz) or one of
the six frequencies derived from the INTOSC
postscaler (125 kHz to 4 MHz). If the internal oscillator
block is supplying the system clock, changing the
states of these bits will have an immediate change on
the internal oscillator’s output.
• Secondary oscillators
• Internal oscillator block
The primary oscillators include the external crystal
and resonator modes, the external RC modes, the
external clock modes and the internal oscillator block.
The particular mode is defined on POR by the contents
of Configuration Register 1H. The details of these
modes are covered earlier in this chapter.
The OSTS, IOFS and T1RUN bits indicate which clock
source is currently providing the system clock. The
OSTS indicates that the Oscillator Start-up Timer has
timed out, and the primary clock is providing the system
clock in primary clock modes. The IOFS bit indicates
when the internal oscillator block has stabilized, and is
providing the system clock in RC clock modes. The
T1RUN bit (T1CON<6>) indicates when the Timer1
oscillator is providing the system clock in secondary
clock modes. In power-managed modes, only one of
these three bits will be set at any time. If none of these
bits are set, the INTRC is providing the system clock, or
the internal oscillator block has just started and is not
yet stable.
The secondary oscillators are those external sources
not connected to the OSC1 or OSC2 pins. These
sources may continue to operate even after the
controller is placed in a power-managed mode.
PIC18F2331/2431/4331/4431 devices offer only the
Timer1 oscillator as a secondary oscillator. This
oscillator, in all power-managed modes, is often the
time base for functions such as a real-time clock.
Most often, a 32.768 kHz watch crystal is connected
between the RC0/T1OSO and RC1/T1OSI pins. Like
the LP mode oscillator circuit, loading capacitors are
also connected from each pin to ground.
The Timer1 oscillator is discussed in greater detail in
Section 12.2 “Timer1 Oscillator”.
The IDLEN bit controls the selective shut down of the
controller’s CPU in power-managed modes. The use of
these bits is discussed in more detail in Section 3.0
“Power-Managed Modes”
In addition to being a primary clock source, the internal
oscillator block is available as a power-managed
mode clock source. The INTRC source is also used as
the clock source for several special features, such as
the WDT and Fail-Safe Clock Monitor.
Note 1: The Timer1 oscillator must be enabled to
select the secondary clock source. The
Timer1 oscillator is enabled by setting the
T1OSCEN bit in the Timer1 Control regis-
ter (T1CON<3>). If the Timer1 oscillator
is not enabled, then any attempt to select
a secondary clock source when execut-
ing a SLEEPinstruction will be ignored.
The clock sources for the PIC18F2331/2431/4331/
4431 devices are shown in Figure 2-8. See
Section 12.0 “Timer1 Module” for further details of
the Timer1 oscillator. See Section 22.1 “Configura-
tion Bits” for Configuration register details.
2: It is recommended that the Timer1 oscil-
lator be operating and stable before exe-
cuting the SLEEP instruction, or a very
long delay may occur while the Timer1
oscillator starts.
DS39616B-page 26
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 2-8:
PIC18F2331/2431/4331/4431 CLOCK DIAGRAM
Clock
Control
PIC18F2331/2431/4331/4431
C4NFIG1H <3:0>
HSPLL
OSCCON<1:0>
Peripherals
Primary Oscillator
OSC2
4 x PLL
Sleep
LP, XT, HS, RC, EC
OSC1
Secondary Oscillator
T1OSC
T1OSO
Clock Source Option
for Other Modules
T1OSCEN
Enable
Oscillator
T1OSI
OSCCON<6:4>
Internal Oscillator
CPU
8 MHz
OSCCON<6:4>
111
110
101
4 MHz
2 MHz
Internal
Oscillator
Block
IDLEN
1 MHz
100
011
010
001
000
500 kHz
250 kHz
125 kHz
31 kHz
8 MHz
(INTOSC)
INTRC
Source
WDT, FSCM
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 27
PIC18F2331/2431/4331/4431
REGISTER 2-2:
OSCCON REGISTER
R/W-0
IDLEN
R/W-0
IRCF2
R/W-0
IRCF1
R/W-0
IRCF0
R(1)
OSTS
R-0
IOFS
R/W-0
SCS1
R/W-0
SCS0
bit 7
bit 0
bit 7
IDLEN: Idle Enable bit
1= Idle mode enabled; CPU core is not clocked in power-managed modes
0= Run mode enabled; CPU core is clocked in power-managed modes
bit 6-4 IRCF2:IRCF0: Internal Oscillator Frequency Select bits
111= 8 MHz (8 MHz source drives clock directly)
110= 4 MHz
101= 2 MHz
100= 1 MHz
011= 500 kHz
010= 250 kHz
001= 125 kHz
000= 31 kHz (INTRC source drives clock directly)
bit 3
bit 2
OSTS: Oscillator Start-up Time-out Status bit
1= Oscillator start-up time-out timer has expired; primary oscillator is running
0= Oscillator start-up time-out timer is running; primary oscillator is not ready
IOFS: INTOSC Frequency Stable bit
1= INTOSC frequency is stable
0= INTOSC frequency is not stable
bit 1-0 SCS1:SCS0: System Clock Select bits
1x= Internal oscillator block (RC modes)
01= Timer1 oscillator (Secondary modes)
00= Primary oscillator (Sleep and PRI_IDLE modes)
Note 1: Depends on state of the IESO bit in Configuration Register 1H.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
2.7.2
OSCILLATOR TRANSITIONS
The PIC18F2331/2431/4331/4431 devices contain
circuitry to prevent clocking “glitches” when switching
between clock sources. A short pause in the system
clock occurs during the clock switch. The length of this
pause is between 8 and 9 clock periods of the new
clock source. This ensures that the new clock source is
stable and that its pulse width will not be less than the
shortest pulse width of the two clock sources.
Clock transitions are discussed in greater detail in
Section 3.1.2 “Entering Power-Managed Modes”.
DS39616B-page 28
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
2.8
Effects of Power-Managed Modes
on the Various Clock Sources
2.9
Power-up Delays
Power-up delays are controlled by two timers, so that
no external Reset circuitry is required for most
applications. The delays ensure that the device is kept
in Reset until the device power supply is stable under
normal circumstances, and the primary clock is
operating and stable. For additional information on
power-up delays, see Sections 4.1 through 4.5.
When the device executes a SLEEP instruction, the
system is switched to one of the power-managed
modes, depending on the state of the IDLEN and
SCS1:SCS0 bits of the OSCCON register. See
Section 3.0 “Power-Managed Modes” for details.
When PRI_IDLE mode is selected, the designated
primary oscillator continues to run without interruption.
For all other power-managed modes, the oscillator
using the OSC1 pin is disabled. The OSC1 pin (and
OSC2 pin, if used by the oscillator) will stop oscillating.
The first timer is the Power-up Timer (PWRT), which
provides a fixed delay on power-up (parameter 33,
Table 25-8), if enabled, in Configuration register 2L.
The second timer is the Oscillator Start-up Timer
(OST), intended to keep the chip in Reset until the crys-
tal oscillator is stable (LP, XT and HS modes). The OST
does this by counting 1024 oscillator cycles before
allowing the oscillator to clock the device.
In secondary clock modes (SEC_RUN and
SEC_IDLE), the Timer1 oscillator is operating and
providing the system clock. The Timer1 oscillator may
also run in all power-managed modes if required to
clock Timer1.
When the HSPLL Oscillator mode is selected, the
device is kept in Reset for an additional 2 ms, following
the HS mode OST delay, so the PLL can lock to the
incoming clock frequency.
In internal oscillator modes (RC_RUN and RC_IDLE),
the internal oscillator block provides the system clock
source. The INTRC output can be used directly to
provide the system clock, and may be enabled to
support various special features, regardless of the
power-managed mode (see Sections 22.2 through
22.4). The INTOSC output at 8 MHz may be used
directly to clock the system, or may be divided down
first. The INTOSC output is disabled if the system clock
is provided directly from the INTRC output.
There is a delay of 5 to 10 µs following POR, while the
controller becomes ready to execute instructions. This
delay runs concurrently with any other delays. This
may be the only delay that occurs when any of the EC,
RC or INTIO modes are used as the primary clock
source.
If the Sleep mode is selected, all clock sources are
stopped. Since all the transistor switching currents
have been stopped, Sleep mode achieves the lowest
current consumption of the device (only leakage
currents).
Enabling any on-chip feature that will operate during
Sleep will increase the current consumed during Sleep.
The INTRC is required to support WDT operation. The
Timer1 oscillator may be operating to support a real-
time clock. Other features may be operating that do not
require a system clock source (i.e., SSP slave, PSP,
INTn pins, A/D conversions and others).
TABLE 2-3:
OSC1 AND OSC2 PIN STATES IN SLEEP MODE
OSC Mode
OSC1 Pin
OSC2 Pin
RC, INTIO1
Floating, external resistor
should pull high
At logic low (clock/4 output)
RCIO, INTIO2
Floating, external resistor
should pull high
Configured as PORTA, bit 6
ECIO
Floating, pulled by external clock
Floating, pulled by external clock
Configured as PORTA, bit 6
At logic low (clock/4 output)
EC
LP, XT, and HS
Feedback inverter disabled, at
quiescent voltage level
Feedback inverter disabled, at
quiescent voltage level
Note:
See Table 4-1 in the Section 4.0 “Reset”, for time-outs due to Sleep and MCLR Reset.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 29
PIC18F2331/2431/4331/4431
NOTES:
DS39616B-page 30
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
3.1
Selecting Power-Managed Modes
3.0
POWER-MANAGED MODES
Selecting a power-managed mode requires deciding if
the CPU is to be clocked or not, and selecting a clock
source. The IDLEN bit controls CPU clocking, while the
SC1:SCS0 bits select a clock source. The individual
modes, bit settings, clock sources and affected
modules are summarized in Table 3-1.
The PIC18F2331/2431/4331/4431 devices offer a total
of six operating modes for more efficient power
management (see Table 3-1). These operating modes
provide a variety of options for selective power
conservation in applications where resources may be
limited (i.e., battery-powered devices).
There are three categories of power-managed modes:
3.1.1
CLOCK SOURCES
• Sleep mode
• Idle modes
• Run modes
The clock source is selected by setting the SCS bits of
the OSCCON register. Three clock sources are avail-
able for use in power-managed idle modes: the primary
clock (as configured in Configuration Register 1H), the
secondary clock (Timer1 oscillator), and the internal
oscillator block. The secondary and internal oscillator
block sources are available for the power-managed
modes (PRI_RUN mode is the normal full power exe-
cution mode; the CPU and peripherals are clocked by
the primary oscillator source).
These categories define which portions of the device
are clocked and sometimes, what speed. The run and
idle modes may use any of the three available clock
sources (Primary, Secondary or INTOSC multiplexer);
the Sleep mode does not use a clock source.
The clock switching feature offered in other PIC18
devices (i.e., using the Timer1 oscillator in place of the
primary oscillator), and the Sleep mode offered by all
PICmicro® devices (where all system clocks are
stopped) are both offered in the PIC18F2331/2431/
4331/4431 devices (SEC_RUN and Sleep modes,
respectively). However, additional power-managed
modes are available that allow the user greater flexibil-
ity in determining what portions of the device are oper-
ating. The power-managed modes are event driven;
that is, some specific event must occur for the device to
enter or (more particularly) exit these operating modes.
For PIC18F2331/2431/4331/4431 devices, the power-
managed modes are invoked by using the existing
SLEEP instruction. All modes exit to PRI_RUN mode
when triggered by an interrupt, a Reset or a WDT time-
out (PRI_RUN mode is the normal full power execution
mode; the CPU and peripherals are clocked by the pri-
mary oscillator source). In addition, power-managed
run modes may also exit to Sleep mode or their
corresponding idle mode.
TABLE 3-1:
Mode
POWER-MANAGED MODES
OSCCON bits
Module Clocking
Available Clock and Oscillator Source
IDLEN SCS1:SCS0
CPU
Peripherals
<7>
<1:0>
Sleep
Off
Off
None – All clocks are disabled
Primary – LP, XT, HS, HSPLL, RC, EC, INTRC(1)
This is the normal full power execution mode.
0
0
00
00
PRI_RUN
Clocked
Clocked
SEC_RUN
RC_RUN
PRI_IDLE
SEC_IDLE
RC_IDLE
0
0
1
1
1
01
1x
00
01
1x
Clocked
Clocked
Off
Clocked
Clocked
Clocked
Clocked
Clocked
Secondary – Timer1 Oscillator
Internal Oscillator Block(1)
Primary – LP, XT, HS, HSPLL, RC, EC
Secondary – Timer1 Oscillator
Internal Oscillator Block(1)
Off
Off
Note 1: Includes INTOSC and INTOSC postscaler, as well as the INTRC source.
2003 Microchip Technology Inc.
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PIC18F2331/2431/4331/4431
3.1.2
ENTERING POWER-MANAGED
MODES
Note 1: Caution should be used when modifying a
single IRCF bit. If VDD is less than 3V, it is
possible to select a higher clock speed
than is supported by the low VDD.
Improper device operation may result if
the VDD/FOSC specifications are violated.
In general, entry, exit and switching between power-
managed clock sources requires clock source switch-
ing. In each case, the sequence of events is the same.
Any change in the power-managed mode begins with
loading the OSCCON register and executing a SLEEP
instruction. The SCS1:SCS0 bits select one of three
power-managed clock sources; the primary clock (as
defined in Configuration Register 1H), the secondary
clock (the Timer1 oscillator) and the internal oscillator
block (used in RC modes). Modifying the SCS bits will
have no effect until a SLEEP instruction is executed.
Entry to the power-managed mode is triggered by the
execution of a SLEEPinstruction.
2: Executing a SLEEP instruction does not
necessarily place the device into Sleep
mode; executing a SLEEP instruction is
simply a trigger to place the controller into
a power-managed mode selected by the
OSCCON register, one of which is Sleep
mode.
3.1.3
MULTIPLE SLEEP COMMANDS
The power-managed mode that is invoked with the
SLEEPinstruction is determined by the settings of the
IDLEN and SCS bits at the time the instruction is exe-
cuted. If another SLEEP instruction is executed, the
device will enter the power-managed mode specified
by these same bits at that time. If the bits have
changed, the device will enter the new power-managed
mode specified by the new bit settings.
Figure 3-5 shows how the system is clocked while
switching from the primary clock to the Timer1 oscilla-
tor. When the SLEEPinstruction is executed, clocks to
the device are stopped at the beginning of the next
instruction cycle. Eight clock cycles from the new clock
source are counted to synchronize with the new clock
source. After eight clock pulses from the new clock
source are counted, clocks from the new clock source
resume clocking the system. The actual length of the
pause is between eight and nine clock periods from the
new clock source. This ensures that the new clock
source is stable and that its pulse width will not be less
than the shortest pulse width of the two clock sources.
3.1.4
COMPARISONS BETWEEN RUN
AND IDLE MODES
Clock source selection for the run modes is identical to
the corresponding idle modes. When a SLEEPinstruc-
tion is executed, the SCS bits in the OSCCON register
are used to switch to a different clock source. As a
result, if there is a change of clock source at the time a
SLEEPinstruction is executed, a clock switch will occur.
Three bits indicate the current clock source: OSTS and
IOFS in the OSCCON register, and T1RUN in the
T1CON register. Only one of these bits will be set while
in a power-managed mode other than PRI_RUN. When
the OSTS bit is set, the primary clock is providing the
system clock. When the IOFS bit is set, the INTOSC
output is providing a stable 8 MHz clock source and is
providing the system clock. When the T1RUN bit is set,
the Timer1 oscillator is providing the system clock. If
none of these bits are set, then either the INTRC clock
source is clocking the system, or the INTOSC source is
not yet stable.
In idle modes, the CPU is not clocked and is not run-
ning. In run modes, the CPU is clocked and executing
code. This difference modifies the operation of the
WDT when it times out. In idle modes, a WDT time-out
results in a wake from power-managed modes. In run
modes, a WDT time-out results in a WDT Reset (see
Table 3-2).
During a wake-up from an idle mode, the CPU starts
executing code by entering the corresponding run
mode, until the primary clock becomes ready. When the
primary clock becomes ready, the clock source is auto-
matically switched to the primary clock. The IDLEN and
SCS bits are unchanged during and after the wake-up.
If the internal oscillator block is configured as the pri-
mary clock source in Configuration Register 1H, then
both the OSTS and IOFS bits may be set when in
PRI_RUN or PRI_IDLE modes. This indicates that the
primary clock (INTOSC output) is generating a stable
8 MHz output. Entering an RC power-managed mode
(same frequency) would clear the OSTS bit.
Figure 3-2 shows how the system is clocked during the
clock source switch. The example assumes the device
was in SEC_IDLE or SEC_RUN mode when a wake is
triggered (the primary clock was configured in HSPLL
mode).
DS39616B-page 32
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TABLE 3-2:
COMPARISON BETWEEN POWER-MANAGED MODES
Power
Managed
Mode
Clock during wake-up
(while primary becomes
ready)
WDT time-out
causes a ...
Peripherals are
clocked by ...
CPU is clocked by ...
Sleep
Not clocked (not running) Wake-up
Not clocked
None or INTOSC multiplexer
if Two-Speed Start-up or
Fail-Safe Clock Monitor are
enabled.
Any idle mode Not clocked (not running) Wake-up
Primary, Secondary or Unchanged from Idle mode
INTOSC multiplexer
(CPU operates as in
corresponding Run mode).
Any run mode
Secondary, or INTOSC
multiplexer
Reset
Secondary or INTOSC Unchanged from Run mode.
multiplexer
3.2
Sleep Mode
3.3
Idle Modes
The power-managed Sleep mode in the PIC18F2331/
2431/4331/4431 devices is identical to that offered in
all other PICmicro® controllers. It is entered by clearing
the IDLEN and SCS1:SCS0 bits (this is the Reset
state), and executing the SLEEPinstruction. This shuts
down the primary oscillator and the OSTS bit is cleared
(see Figure 3-1).
The IDLEN bit allows the controller’s CPU to be selec-
tively shut down while the peripherals continue to oper-
ate. Clearing IDLEN allows the CPU to be clocked.
Setting IDLEN disables clocks to the CPU, effectively
stopping program execution (see Register 2-2). The
peripherals continue to be clocked regardless of the
setting of the IDLEN bit.
When a wake event occurs in Sleep mode (by interrupt,
Reset, or WDT time-out), the system will not be clocked
until the primary clock source becomes ready (see
Figure 3-2), or it will be clocked from the internal oscil-
lator block if either the Two-Speed Start-up or the Fail-
Safe Clock Monitor are enabled (see Section 22.0
“Special Features of the CPU”). In either case, the
OSTS bit is set when the primary clock provides the
system clocks. The IDLEN and SCS bits are not
affected by the wake-up.
There is one exception to how the IDLEN bit functions.
When all the low-power OSCCON bits are cleared
(IDLEN:SCS1:SCS0 = 000), the device enters Sleep
mode upon the execution of the SLEEPinstruction. This
is both the Reset state of the OSCCON register and the
setting that selects Sleep mode. This maintains com-
patibility with other PICmicro devices that do not offer
power-managed modes.
If the Idle Enable bit, IDLEN (OSCCON<7>), is set to a
‘1’ when a SLEEP instruction is executed, the
peripherals will be clocked from the clock source
selected using the SCS1:SCS0 bits; however, the CPU
will not be clocked. Since the CPU is not executing
instructions, the only exits from any of the idle modes
are by interrupt, WDT time-out or a Reset.
When a wake event occurs, CPU execution is delayed
approximately 10 µs while it becomes ready to execute
code. When the CPU begins executing code, it is
clocked by the same clock source as was selected in
the power-managed mode (i.e., when waking from
RC_IDLE mode, the internal oscillator block will clock
the CPU and peripherals until the primary clock source
becomes ready – this is essentially RC_RUN mode).
This continues until the primary clock source becomes
ready. When the primary clock becomes ready, the
OSTS bit is set, and the system clock source is
switched to the primary clock (see Figure 3-4). The
IDLEN and SCS bits are not affected by the wake-up.
While in any idle mode or the Sleep mode, a WDT time-
out will result in a WDT wake-up to full power operation.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 33
PIC18F2331/2431/4331/4431
FIGURE 3-1:
TIMING TRANSITION FOR ENTRY TO SLEEP MODE
Q1 Q2 Q3 Q4 Q1
OSC1
CPU
Clock
Peripheral
Clock
Sleep
Program
Counter
PC
PC + 2
FIGURE 3-2:
TRANSITION TIMING FOR WAKE FROM SLEEP (HSPLL)
Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4 Q1 Q2
OSC1
(1)
(1)
TOST
TPLL
PLL Clock
Output
CPU Clock
Peripheral
Clock
Program
Counter
PC + 4
PC + 6
PC
PC + 2
PC + 8
Wake Event
OSTS bit Set
Note 1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
DS39616B-page 34
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When a wake event occurs, the CPU is clocked from the
primary clock source. A delay of approximately 10 µs is
required between the wake event and when code exe-
cution starts. This is required to allow the CPU to
become ready to execute instructions. After the wake-
up, the OSTS bit remains set. The IDLEN and SCS bits
are not affected by the wake-up (see Figure 3-4).
3.3.1
PRI_IDLE MODE
This mode is unique among the three low-power idle
modes, in that it does not disable the primary system
clock. For timing sensitive applications, this allows for
the fastest resumption of device operation with its more
accurate primary clock source, since the clock source
does not have to “warm up” or transition from another
oscillator.
PRI_IDLE mode is entered by setting the IDLEN bit,
clearing the SCS bits, and executing a SLEEPinstruc-
tion. Although the CPU is disabled, the peripherals
continue to be clocked from the primary clock source
specified in Configuration Register 1H. The OSTS bit
remains set in PRI_IDLE mode (see Figure 3-3).
FIGURE 3-3:
TRANSITION TIMING TO PRI_IDLE MODE
Q3
Q4
Q1
Q1
Q2
OSC1
CPU Clock
Peripheral
Clock
Program
Counter
PC
PC + 2
FIGURE 3-4:
TRANSITION TIMING FOR WAKE FROM PRI_IDLE MODE
Q1
Q3
Q4
Q2
OSC1
CPU Start-up Delay
CPU Clock
Peripheral
Clock
Program
Counter
PC + 2
PC
Wake Event
2003 Microchip Technology Inc.
Preliminary
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When a wake event occurs, the peripherals continue to
be clocked from the Timer1 oscillator. After a 10 µs
delay following the wake event, the CPU begins execut-
ing code, being clocked by the Timer1 oscillator. The
microcontroller operates in SEC_RUN mode until the
primary clock becomes ready. When the primary clock
becomes ready, a clock switch back to the primary clock
occurs (see Figure 3-6). When the clock switch is com-
plete, the T1RUN bit is cleared, the OSTS bit is set and
the primary clock is providing the system clock. The
IDLEN and SCS bits are not affected by the wake-up;
the Timer1 oscillator continues to run.
3.3.2
SEC_IDLE MODE
In SEC_IDLE mode, the CPU is disabled, but the
peripherals continue to be clocked from the Timer1
oscillator. This mode is entered by setting the Idle bit,
modifying to SCS1:SCS0 = 01, and executing a SLEEP
instruction. When the clock source is switched (see
Figure 3-5) to the Timer1 oscillator, the primary oscilla-
tor is shut down, the OSTS bit is cleared and the
T1RUN bit is set.
Note:
The Timer1 oscillator should already be
running prior to entering SEC_IDLE mode.
If the T1OSCEN bit is not set when the
SLEEP instruction is executed, a forced
NOPwill be executed instead and entry to
SEC_IDLE mode will not occur. If the
Timer1 oscillator is enabled, but not yet
running, peripheral clocks will be delayed
until the oscillator has started; in such sit-
uations, initial oscillator operation is far
from stable and unpredictable operation
may result.
FIGURE 3-5:
TIMING TRANSITION FOR ENTRY TO SEC_IDLE MODE
Q1 Q2 Q3 Q4 Q1
1
2
3
4
5
6
7
8
T1OSI
OSC1
Clock Transition
CPU
Clock
Peripheral
Clock
Program
Counter
PC
PC + 2
FIGURE 3-6:
TIMING TRANSITION FOR WAKE FROM SEC_RUN MODE (HSPLL)
Q3
Q4
Q1
Q2 Q3 Q4 Q1 Q2 Q3
Q1
Q2
T1OSI
OSC1
(1)
(1)
TOST
TPLL
PLL Clock
Output
1
2
3
4
5
6
7
8
Clock Transition
CPU Clock
Peripheral
Clock
Program
Counter
PC + 4
PC + 6
PC
PC + 2
OSTS bit Set
Note 1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
Wake from Interrupt Event
DS39616B-page 36
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2003 Microchip Technology Inc.
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was executed, and the INTOSC source was already
stable, the IOFS bit will remain set. If the IRCF bits are
all clear, the INTOSC output is not enabled and the
IOFS bit will remain clear; there will be no indication of
the current clock source.
3.3.3
RC_IDLE MODE
In RC_IDLE mode, the CPU is disabled, but the periph-
erals continue to be clocked from the internal oscillator
block using the INTOSC multiplexer. This mode allows
for controllable power conservation during Idle periods.
When a wake event occurs, the peripherals continue to
be clocked from the INTOSC multiplexer. After a 10 µs
delay following the wake event, the CPU begins exe-
cuting code, being clocked by the INTOSC multiplexer.
The microcontroller operates in RC_RUN mode until
the primary clock becomes ready. When the primary
clock becomes ready, a clock switch back to the pri-
mary clock occurs (see Figure 3-8). When the clock
switch is complete, the IOFS bit is cleared, the OSTS
bit is set, and the primary clock is providing the system
clock. The IDLEN and SCS bits are not affected by the
wake-up. The INTRC source will continue to run if
either the WDT or the Fail-Safe Clock Monitor is
enabled.
This mode is entered by setting the IDLEN bit, setting
SCS1 (SCS0 is ignored), and executing a SLEEP
instruction. The INTOSC multiplexer may be used to
select a higher clock frequency by modifying the IRCF
bits before executing the SLEEPinstruction. When the
clock source is switched to the INTOSC multiplexer
(see Figure 3-7), the primary oscillator is shut down,
and the OSTS bit is cleared.
If the IRCF bits are set to a non-zero value (thus
enabling the INTOSC output), the IOFS bit becomes
set after the INTOSC output becomes stable, in about
1 ms. Clocks to the peripherals continue while the
INTOSC source stabilizes. If the IRCF bits were previ-
ously at a non-zero value before the SLEEPinstruction
FIGURE 3-7:
TIMING TRANSITION TO RC_IDLE MODE
Q1 Q2 Q3 Q4 Q1
1
2
3
4
5
6
7
8
INTRC
OSC1
Clock Transition
CPU
Clock
Peripheral
Clock
Program
Counter
PC
PC + 2
FIGURE 3-8:
TIMING TRANSITION FOR WAKE FROM RC_RUN MODE (RC_RUN TO PRI_RUN)
Q3
Q4
Q1
Q2 Q3 Q4 Q1 Q2 Q3
Q4
Q1
Q2
INTOSC
Multiplexer
OSC1
(1)
(1)
TOST
TPLL
PLL Clock
Output
1
2
3
4
5
6
7
8
Clock Transition
CPU Clock
Peripheral
Clock
Program
Counter
PC + 4
PC + 6
PC
PC + 2
OSTS bit Set
Note 1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
Wake from Interrupt Event
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 37
PIC18F2331/2431/4331/4431
SEC_RUN mode is entered by clearing the IDLEN bit,
setting SCS1:SCS0 = 01, and executing a SLEEP
instruction. The system clock source is switched to the
Timer1 oscillator (see Figure 3-9), the primary oscilla-
tor is shut down, the T1RUN bit (T1CON<6>) is set and
the OSTS bit is cleared.
3.4
Run Modes
If the IDLEN bit is clear when a SLEEP instruction is
executed, the CPU and peripherals are both clocked
from the source selected using the SCS1:SCS0 bits.
While these operating modes may not afford the power
conservation of Idle or Sleep modes, they do allow the
device to continue executing instructions by using a
lower frequency clock source. RC_RUN mode also
offers the possibility of executing code at a frequency
greater than the primary clock.
Note:
The Timer1 oscillator should already be
running prior to entering SEC_RUN mode.
If the T1OSCEN bit is not set when the
SLEEP instruction is executed, a forced
NOPwill be executed instead and entry to
SEC_IDLE mode will not occur. If the
Timer1 oscillator is enabled, but not yet
running, system clocks will be delayed
until the oscillator has started. In such
situations, initial oscillator operation is far
from stable and unpredictable operation
may result.
Wake-up from a power-managed run mode can be trig-
gered by an interrupt, or any Reset, to return to full
power operation. As the CPU is executing code in run
modes, several additional exits from run modes are
possible. They include exit to Sleep mode, exit to a cor-
responding idle mode, and exit by executing a RESET
instruction. While the device is in any of the power-
managed run modes, a WDT time-out will result in a
WDT Reset.
When a wake event occurs, the peripherals and CPU
continue to be clocked from the Timer1 oscillator while
the primary clock is started. When the primary clock
becomes ready, a clock switch back to the primary clock
occurs (see Figure 3-6). When the clock switch is com-
plete, the T1RUN bit is cleared, the OSTS bit is set, and
the primary clock is providing the system clock. The
IDLEN and SCS bits are not affected by the wake-up;
the Timer1 oscillator continues to run.
3.4.1
PRI_RUN MODE
The PRI_RUN mode is the normal full power execution
mode. If the SLEEPinstruction is never executed, the
microcontroller operates in this mode (a SLEEPinstruc-
tion is executed to enter all other power-managed
modes). All other power-managed modes exit to
PRI_RUN mode when an interrupt or WDT time-out
occur.
Firmware can force an exit from SEC_RUN mode. By
clearing the T1OSCEN bit (T1CON<3>), an exit from
SEC_RUN back to normal full power operation is trig-
gered. The Timer1 oscillator will continue to run and
provide the system clock even though the T1OSCEN bit
is cleared. The primary clock is started. When the pri-
mary clock becomes ready, a clock switch back to the
primary clock occurs (see Figure 3-6). When the clock
switch is complete, the Timer1 oscillator is disabled, the
T1RUN bit is cleared, the OSTS bit is set and the pri-
mary clock provides the system clock. The IDLEN and
SCS bits are not affected by the wake-up.
There is no entry to PRI_RUN mode. The OSTS bit is
set. The IOFS bit may be set if the internal oscillator
block is the primary clock source (see Section 2.7.1
“Oscillator Control Register”).
3.4.2
SEC_RUN MODE
The SEC_RUN mode is the compatible mode to the
“clock switching” feature offered in other PIC18
devices. In this mode, the CPU and peripherals are
clocked from the Timer1 oscillator. This gives users the
option of lower power consumption while still using a
high accuracy clock source.
FIGURE 3-9:
TIMING TRANSITION FOR ENTRY TO SEC_RUN MODE
Q1 Q2 Q3 Q4 Q1
Q2
Q3
Q4
Q1
Q2
Q3
1
2
3
4
5
6
7
8
T1OSI
OSC1
Clock Transition
CPU
Clock
Peripheral
Clock
Program
Counter
PC
PC + 2
PC + 2
DS39616B-page 38
Preliminary
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3.4.3
RC_RUN MODE
Note:
Caution should be used when modifying a
single IRCF bit. If VDD is less than 3V, it is
possible to select a higher clock speed
than is supported by the low VDD.
Improper device operation may result if
the VDD/FOSC specifications are violated.
In RC_RUN mode, the CPU and peripherals are
clocked from the internal oscillator block using the
INTOSC multiplexer, and the primary clock is shut
down. When using the INTRC source, this mode pro-
vides the best power conservation of all the run modes,
while still executing code. This mode works well for
user applications that are not highly timing sensitive, or
do not require high-speed clocks at all times.
If the IRCF bits are all clear, the INTOSC output is not
enabled, and the IOFS bit will remain clear; there will
be no indication of the current clock source. The INTRC
source is providing the system clocks.
If the primary clock source is the internal oscillator
block (either of the INTIO1 or INTIO2 oscillators), there
are no distinguishable differences between PRI_RUN
and RC_RUN modes during execution. However, a
clock switch delay will occur during entry to, and exit
from, RC_RUN mode. Therefore, if the primary clock
source is the internal oscillator block, the use of
RC_RUN mode is not recommended.
If the IRCF bits are changed from all clear (thus
enabling the INTOSC output), the IOFS bit becomes
set after the INTOSC output becomes stable. Clocks to
the system continue while the INTOSC source
stabilizes in approximately 1 ms.
If the IRCF bits were previously at a non-zero value
before the SLEEP instruction was executed, and the
INTOSC source was already stable, the IOFS bit will
remain set.
This mode is entered by clearing the IDLEN bit, setting
SCS1 (SCS0 is ignored) and executing a SLEEP
instruction. The IRCF bits may select the clock
frequency before the SLEEP instruction is executed.
When the clock source is switched to the INTOSC
multiplexer (see Figure 3-10), the primary oscillator is
shut down and the OSTS bit is cleared.
When a wake event occurs, the system continues to be
clocked from the INTOSC multiplexer while the primary
clock is started. When the primary clock becomes
ready, a clock switch to the primary clock occurs (see
Figure 3-8). When the clock switch is complete, the
IOFS bit is cleared, the OSTS bit is set and the primary
clock provides the system clock. The IDLEN and SCS
bits are not affected by the wake-up. The INTRC
source will continue to run if either the WDT or the
Fail-Safe Clock Monitor is enabled.
The IRCF bits may be modified at any time to immedi-
ately change the system clock speed. Executing a
SLEEPinstruction is not required to select a new clock
frequency from the INTOSC multiplexer.
FIGURE 3-10:
TIMING TRANSITION TO RC_RUN MODE
Q4 Q1 Q2 Q3 Q4 Q1
Q2
Q3
Q4
Q1
Q2
Q3
1
2
3
4
5
6
7
8
INTRC
OSC1
Clock Transition
CPU
Clock
Peripheral
Clock
Program
Counter
PC
PC + 2
PC + 4
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3.4.4
EXIT TO IDLE MODE
3.5
Wake From Power-Managed
Modes
An exit from a power-managed run mode to its corre-
sponding idle mode is executed by setting the IDLEN
bit and executing a SLEEP instruction. The CPU is
halted at the beginning of the instruction following the
SLEEPinstruction. There are no changes to any of the
clock source status bits (OSTS, IOFS, or T1RUN).
While the CPU is halted, the peripherals continue to be
clocked from the previously selected clock source.
An exit from any of the power-managed modes is trig-
gered by an interrupt, a Reset or a WDT time-out. This
section discusses the triggers that cause exits from
power-managed modes. The clocking subsystem
actions are discussed in each of the power-managed
modes (see Sections 3.2 through 3.4).
Note:
If application code is timing sensitive, it
should wait for the OSTS bit to become set
before continuing. Use the interval during
the Low-power exit sequence (before
OSTS is set) to perform timing insensitive
“housekeeping” tasks.
3.4.5
EXIT TO SLEEP MODE
An exit from a power-managed run mode to Sleep
mode is executed by clearing the IDLEN and
SCS1:SCS0 bits and executing a SLEEP instruction.
The code is no different than the method used to invoke
Sleep mode from the normal operating (full power)
mode.
Device behavior during Low-power mode exits is
summarized in Table 3-3.
The primary clock and internal oscillator block are dis-
abled. The INTRC will continue to operate if the WDT
is enabled. The Timer1 oscillator will continue to run, if
enabled, in the T1CON register. All clock source status
bits are cleared (OSTS, IOFS and T1RUN).
3.5.1
EXIT BY INTERRUPT
Any of the available interrupt sources can cause the
device to exit a power-managed mode and resume full
power operation. To enable this functionality, an inter-
rupt source must be enabled by setting its enable bit in
one of the INTCON or PIE registers. The exit sequence
is initiated when the corresponding interrupt flag bit is
set. On all exits from Low-power mode by interrupt,
code execution branches to the interrupt vector if the
GIE/GIEH bit (INTCON<7>) is set. Otherwise, code
execution continues or resumes without branching
(see Section 9.0 “Interrupts”).
DS39616B-page 40
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 3-3:
ACTIVITY AND EXIT DELAY ON WAKE FROM SLEEP MODE OR ANY IDLE MODE
(BY CLOCK SOURCES)
Power-
Managed
Mode Exit
Delay
Activity During Wake from
Power-Managed Mode
ClockReady
Status bit
(OSCCON)
Clock in Power- Primary System
Managed Mode
Clock
Exit by Interrupt
Exit by Reset
LP, XT, HS
CPU and peripherals Not clocked, or
OSTS
Primary System
Clock
(PRI_IDLE mode)
clocked by primary
clock and executing
instructions.
Two-Speed Start-up
(if enabled)(3)
HSPLL
5-10 µs(5)
.
EC, RC, INTRC(1)
INTOSC(2)
LP, XT, HS
HSPLL
EC, RC, INTRC(1)
INTOSC(2)
LP, XT, HS
HSPLL
EC, RC, INTRC(1)
INTOSC(2)
LP, XT, HS
HSPLL
EC, RC, INTRC(1)
INTOSC(2)
—
IOFS
OST
OST + 2 ms
5-10 µs(5)
1 ms(4)
CPU and peripherals
clocked by selected
power-managed mode
clock and executing
instructions until
OSTS
T1OSC or
INTRC(1)
—
IOFS
primary clock source
becomes ready.
OST
OSTS
OST + 2 ms
5-10 µs(5)
None
INTOSC(2)
—
IOFS
OST
Not clocked or
OSTS
Two-Speed Start-up (if
enabled) until primary
clock source becomes
OST + 2 ms
5-10 µs(5)
1 ms(4)
Sleep mode
—
ready(3)
.
IOFS
Note 1: In this instance, refers specifically to the INTRC clock source.
2: Includes both the INTOSC 8 MHz source and postscaler derived frequencies.
3: Two-Speed Start-up is covered in greater detail in Section 22.3 “Two-Speed Start-up”.
4: Execution continues during the INTOSC stabilization period.
5: Required delay when waking from Sleep and all idle modes. This delay runs concurrently with any other
required delays (see Section 3.3 “Idle Modes”).
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 41
PIC18F2331/2431/4331/4431
3.5.2
EXIT BY RESET
3.5.4
EXIT WITHOUT AN OSCILLATOR
START-UP DELAY
Normally, the device is held in Reset by the Oscillator
Start-up Timer (OST) until the primary clock (defined in
Configuration register 1H) becomes ready. At that time,
the OSTS bit is set and the device begins executing
code.
Certain exits from power-managed modes do not
invoke the OST at all. These are:
• PRI_IDLE mode where the primary clock source
is not stopped; and
Code execution can begin before the primary clock
becomes ready. If either the Two-Speed Start-up (see
Section 22.3 “Two-Speed Start-up”) or Fail-Safe
Clock Monitor (see Section 22.4 “Fail-Safe Clock
Monitor”) are enabled in Configuration Register 1H,
the device may begin execution as soon as the Reset
source has cleared. Execution is clocked by the
INTOSC multiplexer driven by the internal oscillator
block. Since the OSCCON register is cleared following
all Resets, the INTRC clock source is selected. A
higher speed clock may be selected by modifying the
IRCF bits in the OSCCON register. Execution is
clocked by the internal oscillator block until either the
primary clock becomes ready, or a power-managed
mode is entered before the primary clock becomes
ready; the primary clock is then shut down.
• the primary clock source is not any of LP, XT, HS
or HSPLL modes.
In these cases, the primary clock source either does
not require an oscillator start-up delay, since it is
already running (PRI_IDLE), or normally does not
require an oscillator start-up delay (RC, EC, and INTIO
oscillator modes).
However, a fixed delay (approximately 10 µs) following
the wake event is required when leaving Sleep and idle
modes. This delay is required for the CPU to prepare
for execution. Instruction execution resumes on the first
clock cycle following this delay.
3.6
INTOSC Frequency Drift
The factory calibrates the internal oscillator block out-
put (INTOSC) for 8 MHz. However, this frequency may
drift as VDD or temperature changes, which can affect
the controller operation in a variety of ways.
3.5.3
EXIT BY WDT TIME-OUT
A WDT time-out will cause different actions depending
on which power-managed mode the device is in when
the time-out occurs.
It is possible to adjust the INTOSC frequency by modi-
fying the value in the OSCTUNE register. This has the
side effect that the INTRC clock source frequency is
also affected. However, the features that use the
INTRC source often do not require an exact frequency.
These features include the Fail-Safe Clock Monitor, the
Watchdog Timer and the RC_RUN/RC_IDLE modes
when the INTRC clock source is selected.
If the device is not executing code (all idle modes and
Sleep mode), the time-out will result in a wake from the
power-managed mode (see Section 3.2 “Sleep
Mode” through Section 3.4 “Run Modes”).
If the device is executing code (all run modes), the
time-out will result in a WDT Reset (see Section 22.2
“Watchdog Timer (WDT)”).
Being able to adjust the INTOSC requires knowing
when an adjustment is required, in which direction it
should be made, and in some cases, how large a
change is needed. Three examples follow, but other
techniques may be used.
The WDT timer and postscaler are cleared by execut-
ing a SLEEPor CLRWDTinstruction, the loss of a cur-
rently selected clock source (if the Fail-Safe Clock
Monitor is enabled), and modifying the IRCF bits in the
OSCCON register if the internal oscillator block is the
system clock source.
DS39616B-page 42
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
3.6.1
EXAMPLE – USART
3.6.3
EXAMPLE – CCP IN CAPTURE
MODE
An adjustment may be indicated when the USART
begins to generate framing errors, or receives data with
errors while in Asynchronous mode. Framing errors
indicate that the system clock frequency is too high –
try decrementing the value in the OSCTUNE register to
reduce the system clock frequency. Errors in data
may suggest that the system clock speed is too low –
increment OSCTUNE.
A CCP module can use free running Timer1, clocked by
the internal oscillator block and an external event with
a known period (i.e., AC power frequency). The time of
the first event is captured in the CCPRxH:CCPRxL
registers and is recorded for use later. When the
second event causes a capture, the time of the first
event is subtracted from the time of the second event.
Since the period of the external event is known, the
time difference between events can be calculated.
3.6.2
EXAMPLE – TIMERS
This technique compares system clock speed to some
reference clock. Two timers may be used; one timer is
clocked by the peripheral clock, while the other is
clocked by a fixed reference source, such as the
Timer1 oscillator.
If the measured time is much greater than the
calculated time, the internal oscillator block is running
too fast – decrement OSCTUNE. If the measured time
is much less than the calculated time, the internal
oscillator block is running too slow – increment
OSCTUNE.
Both timers are cleared, but the timer clocked by the
reference generates interrupts. When an interrupt
occurs, the internally clocked timer is read and both
timers are cleared. If the internally clocked timer value
is greater than expected, then the internal oscillator
block is running too fast – decrement OSCTUNE.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 43
PIC18F2331/2431/4331/4431
NOTES:
DS39616B-page 44
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
Most registers are not affected by a WDT wake-up,
since this is viewed as the resumption of normal
4.0
RESET
The PIC18F2331/2431/4331/4431 devices differenti-
ate between various kinds of Reset:
operation. Status bits from the RCON register, RI, TO,
PD, POR and BOR, are set or cleared differently in
different Reset situations, as indicated in Table 4-2.
These bits are used in software to determine the nature
of the Reset. See Table 4-3 for a full description of the
Reset states of all registers.
a) Power-on Reset (POR)
b) MCLR Reset during normal operation
c) MCLR Reset during Sleep
d) Watchdog Timer (WDT) Reset (during
execution)
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 4-1.
e) Programmable Brown-out Reset (BOR)
f) RESETInstruction
The enhanced MCU devices have a MCLR noise filter
in the MCLR Reset path. The filter will detect and
ignore small pulses.
g) Stack Full Reset
h) Stack Underflow Reset
The MCLR pin is not driven low by any internal Resets,
including the WDT.
Most registers are unaffected by a Reset. Their status
is unknown on POR and unchanged by all other
Resets. The other registers are forced to a “Reset
state” depending on the type of Reset that occurred.
The MCLR input provided by the MCLR pin can be dis-
abled with the MCLRE bit in Configuration Register 3H
(CONFIG3H<7>). See Section 22.1 “Configuration
Bits” for more information.
FIGURE 4-1:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
RESET
Instruction
Stack
Pointer
Stack Full/Underflow Reset
External Reset
MCLRE
MCLR
( )_IDLE
Sleep
WDT
Time-out
VDD Rise
Detect
POR Pulse
BOREN
VDD
Brown-out
Reset
S
OST/PWRT
OST
10-bit Ripple Counter
1024 Cycles
Chip_Reset
R
Q
OSC1
32 µs
65.5 ms
PWRT
11-bit Ripple Counter
INTRC(1)
Enable PWRT
(2)
Enable OST
Note 1: This is the INTRC source from the internal oscillator block, and is separate from the RC oscillator of the CLKI pin.
2: See Table 4-1 for time-out situations.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 45
PIC18F2331/2431/4331/4431
4.1
Power-on Reset (POR)
4.3
Oscillator Start-up Timer (OST)
A Power-on Reset pulse is generated on-chip when
VDD rise is detected. To take advantage of the POR cir-
cuitry, just tie the MCLR pin through a resistor (1k to
10 kΩ) to VDD. This will eliminate external RC compo-
nents usually needed to create a Power-on Reset
delay. A minimum rise rate for VDD is specified
(parameter D004). For a slow rise time, see Figure 4-2.
The Oscillator Start-up Timer (OST) provides a 1024
oscillator cycle (from OSC1 input) delay after the
PWRT delay is over (parameter #33). This ensures that
the crystal oscillator or resonator has started and
stabilized.
The OST time-out is invoked only for XT, LP, HS and
HSPLL modes, and only on Power-on Reset or on exit
from most power-managed modes.
When the device starts normal operation (i.e., exits the
Reset condition), device operating parameters (volt-
age, frequency, temperature, etc.) must be met to
ensure operation. If these conditions are not met, the
device must be held in Reset until the operating
conditions are met.
4.4
PLL Lock Time-out
With the PLL enabled in its PLL mode, the time-out
sequence following a Power-on Reset is slightly differ-
ent from other oscillator modes. A portion of the Power-
up Timer is used to provide a fixed time-out that is suf-
ficient for the PLL to lock to the main oscillator fre-
quency. This PLL lock time-out (TPLL) is typically 2 ms
and follows the oscillator start-up time-out.
FIGURE 4-2:
EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW VDD POWER-UP)
VDD
VDD
D
4.5
Brown-out Reset (BOR)
A configuration bit, BOREN, can disable (if clear/
programmed) or enable (if set) the Brown-out Reset cir-
cuitry. If VDD falls below VBOR (parameter D005) for
greater than TBOR (parameter #35), the brown-out situ-
ation will reset the chip. A Reset may not occur if VDD
falls below VBOR for less than TBOR. The chip will
remain in Brown-out Reset until VDD rises above VBOR.
If the Power-up Timer is enabled, it will be invoked after
VDD rises above VBOR; it then will keep the chip in
Reset for an additional time delay TPWRT (parameter
#33). If VDD drops below VBOR while the Power-up
Timer is running, the chip will go back into a Brown-out
Reset and the Power-up Timer will be initialized. Once
VDD rises above VBOR, the Power-up Timer will execute
the additional time delay. Enabling BOR Reset does
not automatically enable the PWRT.
R
R1
MCLR
PIC18FXXXX
C
Note 1: External Power-on Reset circuit is
required only if the VDD power-up slope
is too slow. The diode D helps discharge
the capacitor quickly when VDD powers
down.
2: R < 40 kΩ is recommended to make
sure that the voltage drop across R does
not violate the device’s electrical specifi-
cation.
3: R1 ≥ 1 kΩ will limit any current flowing
into MCLR from external capacitor C, in
the event of MCLR/VPP pin breakdown,
due to Electrostatic Discharge (ESD) or
Electrical Overstress (EOS).
4.6
Time-out Sequence
On power-up, the time-out sequence is as follows:
First, after the POR pulse has cleared, PWRT time-out
is invoked (if enabled). Then, the OST is activated. The
total time-out will vary based on oscillator configuration
and the status of the PWRT. For example, in RC mode
with the PWRT disabled, there will be no time-out at all.
Figures 4-3 through 4-7 depict time-out sequences on
power-up.
4.2
Power-up Timer (PWRT)
The Power-up Timer (PWRT) of the PIC18F2331/2431/
4331/4431 devices is an 11-bit counter, which uses the
INTRC source as the clock input. This yields a count of
2048 x 32 µs = 65.6 ms. While the PWRT is counting,
the device is held in Reset.
Since the time-outs occur from the POR pulse, if MCLR
is kept low long enough, all time-outs will expire. Bring-
ing MCLR high will begin execution immediately
(Figure 4-5). This is useful for testing purposes or to
synchronize more than one PIC18FXXXX device
operating in parallel.
The power-up time delay depends on the INTRC clock
and will vary from chip-to-chip due to temperature and
process variation. See DC parameter #33 for details.
Table 4-2 shows the Reset conditions for some Special
Function registers, while Table 4-3 shows the Reset
conditions for all the registers.
The PWRT is enabled by clearing configuration bit
PWRTEN.
DS39616B-page 46
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 4-1:
Oscillator
TIME-OUT IN VARIOUS SITUATIONS
Power-up(2) and Brown-out
Exit from
Configuration
Power-Managed Mode
PWRTEN = 0
PWRTEN = 1
HSPLL
66 ms(1) + 1024 TOSC + 2 ms(2)
66 ms(1) + 1024 TOSC
66 ms(1)
1024 TOSC + 2 ms(2)
1024 TOSC + 2 ms(2)
HS, XT, LP
EC, ECIO
1024 TOSC
1024 TOSC
—
—
—
—
—
—
RC, RCIO
66 ms(1)
66 ms(1)
INTIO1, INTIO2
Note 1: 66 ms (65.5 ms) is the nominal Power-up Timer (PWRT) delay.
2: 2 ms is the nominal time required for the 4x PLL to lock.
REGISTER 4-1:
RCON REGISTER BITS AND POSITIONS
R/W-0
IPEN
U-0
—
U-0
—
R/W-1
RI
R-1
TO
R-1
PD
R/W-1
POR
R/W-1
BOR
bit 7
Note:
bit 0
Refer to Section 5.14 “RCON Register” for bit definitions.
TABLE 4-2:
STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION FOR
RCON REGISTER
Program
Counter
RCON
Register
Condition
RI TO PD POR BOR STKFUL STKUNF
Power-on Reset
RESETInstruction
Brown-out
0000h
0000h
0000h
0000h
0--1 1100
0--0 uuuu
0--1 11u-
0--u 1uuu
1
0
1
u
1
u
1
1
1
u
1
u
0
u
u
u
0
u
0
u
0
u
u
u
0
u
u
u
MCLR during power-managed
run modes
MCLR during power-managed
idle modes and Sleep
0000h
0000h
0--u 10uu
0--u 0uuu
u
u
1
0
0
u
u
u
u
u
u
u
u
u
WDT Time-out during full power
or power-managed Run
MCLR during full power
execution
u
u
Stack Full Reset (STVREN = 1)
0000h
0--u uuuu
u
u
u
u
u
1
u
u
1
Stack Underflow Reset
(STVREN = 1)
Stack Underflow Error (not an
actual Reset, STVREN = 0)
0000h
PC + 2
u--u uuuu
u--u 00uu
u--u u0uu
u
u
u
u
0
u
u
0
0
u
u
u
u
u
u
u
u
u
1
u
u
WDT Time-out during power-
managed Idle or Sleep
Interrupt Exit from power-man-
aged modes
PC + 2(1)
Legend: u= unchanged, x= unknown, - = unimplemented bit, read as ‘0’.
Note 1: When the wake-up is due to an interrupt and the GIEH or GIEL bits are set, the PC is loaded with the
interrupt vector (0x000008h or 0x000018h).
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 47
PIC18F2331/2431/4331/4431
TABLE 4-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS
MCLR Resets
Power-on Reset,
Brown-out Reset
WDT Reset
RESET Instruction
Wake-up via WDT
or Interrupt
Register
Applicable Devices
Stack Resets
TOSU
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
---0 0000
0000 0000
0000 0000
00-0 0000
---0 0000
0000 0000
0000 0000
--00 0000
0000 0000
0000 0000
0000 0000
xxxx xxxx
xxxx xxxx
0000 000x
1111 -1-1
11-0 0-00
N/A
---0 0000
0000 0000
0000 0000
uu-0 0000
---0 0000
0000 0000
0000 0000
--00 0000
0000 0000
0000 0000
0000 0000
uuuu uuuu
uuuu uuuu
0000 000u
1111 -1-1
11-0 0-00
N/A
---0 uuuu(3)
uuuu uuuu(3)
uuuu uuuu(3)
uu-u uuuu(3)
---u uuuu
uuuu uuuu
PC + 2(2)
--uu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu(1)
uuuu -u-u(1)
uu-u u-uu(1)
N/A
TOSH
TOSL
STKPTR
PCLATU
PCLATH
PCL
TBLPTRU
TBLPTRH
TBLPTRL
TABLAT
PRODH
PRODL
INTCON
INTCON2
INTCON3
INDF0
POSTINC0
N/A
N/A
N/A
POSTDEC0 2331 2431 4331 4431
N/A
N/A
N/A
PREINC0
PLUSW0
FSR0H
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
N/A
N/A
N/A
N/A
N/A
N/A
---- xxxx
xxxx xxxx
xxxx xxxx
N/A
---- uuuu
uuuu uuuu
uuuu uuuu
N/A
---- uuuu
uuuu uuuu
uuuu uuuu
N/A
FSR0L
WREG
INDF1
POSTINC1
N/A
N/A
N/A
POSTDEC1 2331 2431 4331 4431
N/A
N/A
N/A
PREINC1
PLUSW1
2331 2431 4331 4431
2331 2431 4331 4431
N/A
N/A
N/A
N/A
N/A
N/A
Legend: u= unchanged, x= unknown, -= unimplemented bit, read as ‘0’, q= value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 4-2 for Reset value for specific condition.
5: Bits 6 and 7 of PORTA, LATA and TRISA are enabled, depending on the Oscillator mode selected. When
not enabled as PORTA pins, they are disabled and read ‘0’.
6: Bit 3 of PORTE and LATE are enabled if MCLR functionality is disabled. When not enabled as the PORTE
pin, they are disabled and read as ‘0’. The 28-pin devices have only RE3 on PORTE when MCLR is
disabled.
DS39616B-page 48
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 4-3:
Register
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
MCLR Resets
WDT Reset
Power-on Reset,
Brown-out Reset
Wake-up via WDT
or Interrupt
Applicable Devices
RESET Instruction
Stack Resets
FSR1H
FSR1L
BSR
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
---- xxxx
xxxx xxxx
---- 0000
N/A
---- uuuu
uuuu uuuu
---- 0000
N/A
---- uuuu
uuuu uuuu
---- uuuu
N/A
INDF2
POSTINC2
N/A
N/A
N/A
POSTDEC2 2331 2431 4331 4431
N/A
N/A
N/A
PREINC2
PLUSW2
FSR2H
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
N/A
N/A
N/A
N/A
N/A
N/A
---- xxxx
xxxx xxxx
---x xxxx
0000 0000
xxxx xxxx
11-- 1111
0000 0000
--00 0101
---- ---0
0--1 11q0
xxxx xxxx
xxxx xxxx
0000 0000
0000 0000
1111 1111
-000 0000
xxxx xxxx
0000 0000
0000 0000
0000 0000
---- uuuu
uuuu uuuu
---u uuuu
0000 0000
uuuu uuuu
11-- 1111
0000 0000
--00 0101
---- ---0
0--q qquu
uuuu uuuu
uuuu uuuu
u0uu uuuu
0000 0000
1111 1111
-000 0000
uuuu uuuu
0000 0000
0000 0000
0000 0000
---- uuuu
uuuu uuuu
---u uuuu
uuuu uuuu
uuuu uuuu
uu-- uuuu
uuuu uuuu
--uu uuuu
---- ---u
u--u qquu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
1111 1111
-uuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
FSR2L
STATUS
TMR0H
TMR0L
T0CON
OSCCON
LVDCON
WDTCON
RCON(4)
TMR1H
TMR1L
T1CON
TMR2
PR2
T2CON
SSPBUF
SSPADD
SSPSTAT
SSPCON
Legend: u= unchanged, x= unknown, -= unimplemented bit, read as ‘0’, q= value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 4-2 for Reset value for specific condition.
5: Bits 6 and 7 of PORTA, LATA and TRISA are enabled, depending on the Oscillator mode selected. When
not enabled as PORTA pins, they are disabled and read ‘0’.
6: Bit 3 of PORTE and LATE are enabled if MCLR functionality is disabled. When not enabled as the PORTE
pin, they are disabled and read as ‘0’. The 28-pin devices have only RE3 on PORTE when MCLR is
disabled.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 49
PIC18F2331/2431/4331/4431
TABLE 4-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
MCLR Resets
Power-on Reset,
Brown-out Reset
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
Register
Applicable Devices
ADRESH
ADRESL
ADCON0
ADCON1
ADCON2
CCPR1H
CCPR1L
CCP1CON
CCPR2H
CCPR2L
CCP2CON
ANSEL0
ANSEL1
T5CON
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
xxxx xxxx
xxxx xxxx
--00 0000
00-0 1000
0000 0000
xxxx xxxx
xxxx xxxx
--00 0000
xxxx xxxx
xxxx xxxx
--00 0000
1111 1111
---- ---0
0000 0000
0000 0000
0000 0000
0000 0000
0000 0000
0000 0000
0000 -010
0000 000x
-1-1 0-00
0000 0000
0000 0000
xx-0 x000
0000 0000
---1 1111
---0 0000
---0 0000
uuuu uuuu
uuuu uuuu
--00 0000
00-- 1000
0000 0000
uuuu uuuu
uuuu uuuu
--00 0000
uuuu uuuu
uuuu uuuu
--00 0000
1111 1111
---- ---0
0000 0000
0000 0000
0000 0000
0000 0000
0000 0000
0000 0000
0000 -010
0000 000x
-1-1 0-00
0000 0000
0000 0000
uu-0 u000
0000 0000
---1 1111
---0 0000
---0 0000
uuuu uuuu
uuuu uuuu
--uu uuuu
uu-u uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
--uu uuuu
uuuu uuuu
uuuu uuuu
--uu uuuu
uuuu uuuu
---- ---u
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu -uuu
uuuu uuuu
-u-u u-uu
uuuu uuuu
uuuu uuuu
uu-0 u000
0000 0000
---u uuuu
---u uuuu
---u uuuu
QEICON
SPBRGH
SPBRG
RCREG
TXREG
TXSTA
RCSTA
BAUDCTL
EEADR
EEDATA
EECON1
EECON2
IPR3
PIE3
PIR3
Legend: u= unchanged, x= unknown, -= unimplemented bit, read as ‘0’, q= value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 4-2 for Reset value for specific condition.
5: Bits 6 and 7 of PORTA, LATA and TRISA are enabled, depending on the Oscillator mode selected. When
not enabled as PORTA pins, they are disabled and read ‘0’.
6: Bit 3 of PORTE and LATE are enabled if MCLR functionality is disabled. When not enabled as the PORTE
pin, they are disabled and read as ‘0’. The 28-pin devices have only RE3 on PORTE when MCLR is
disabled.
DS39616B-page 50
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 4-3:
Register
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
MCLR Resets
WDT Reset
Power-on Reset,
Brown-out Reset
Wake-up via WDT
or Interrupt
Applicable Devices
RESET Instruction
Stack Resets
IPR2
PIR2
PIE2
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
1--1 -1-1
0--0 -0-0
0--0 -0-0
1111 1111
-111 1111
-000 0000
-000 0000
0000 0000
-000 0000
--00 0000
00-0 0000
0000 0000
---- -111
1111 1111
1111 1111
1111 1111
1111 1111(5)
1111 1111
1111 1111
---- -xxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx(5)
xxxx xxxx
xxxx xxxx
---- xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
xx0x 0000(5)
1--1 -1-1
0--0 -0-0
0--0 -0-0
1111 1111
-111 1111
-000 0000
-000 0000
0000 0000
-000 0000
--00 0000
00-0 0000
0000 0000
---- -111
1111 1111
1111 1111
1111 1111
1111 1111(5)
1111 1111
1111 1111
---- -uuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu(5)
uuuu uuuu
uuuu uuuu
---- xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uu0u 0000(5)
u--u -u-u
u--u -u-u
u--u -u-u
uuuu uuuu
-uuu uuuu
-uuu uuuu(1)
-uuu uuuu(1)
uuuu uuuu
-uuu uuuu
--uu uuuu
uu-u uuuu
uuuu uuuu
---- -uuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu(5)
uuuu uuuu
uuuu uuuu
---- -uuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu(5)
uuuu uuuu
uuuu uuuu
---- uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu(5)
IPR1
PIR1
PIE1
OSCTUNE
ADCON3
ADCHS
TRISE(6)
TRISD
TRISC
TRISB
TRISA(5)
PR5H
PR5L
LATE(6)
LATD
LATC
LATB
LATA(5)
TMR5H
TMR5L
PORTE(6)
PORTD
PORTC
PORTB
PORTA(5)
Legend: u= unchanged, x= unknown, -= unimplemented bit, read as ‘0’, q= value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 4-2 for Reset value for specific condition.
5: Bits 6 and 7 of PORTA, LATA and TRISA are enabled, depending on the Oscillator mode selected. When
not enabled as PORTA pins, they are disabled and read ‘0’.
6: Bit 3 of PORTE and LATE are enabled if MCLR functionality is disabled. When not enabled as the PORTE
pin, they are disabled and read as ‘0’. The 28-pin devices have only RE3 on PORTE when MCLR is
disabled.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 51
PIC18F2331/2431/4331/4431
TABLE 4-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
MCLR Resets
Power-on Reset,
Brown-out Reset
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
Register
Applicable Devices
PTCON0
2331 2431 4331 4431
uuuu uuuu
0000 0000
00-- ----
0000 0000
---- 0000
1111 1111
---- 1111
--00 0000
0000 0000
0000 0000
--00 0000
0000 0000
--00 0000
0000 0000
--00 0000
0000 0000
---- 0000
-101 0000
0000 0-00
0000 0000
-000 0000
1111 1111
0000 0000
uuuu uuuu
00-- ----
0000 0000
---- 0000
1111 1111
---- 1111
--00 0000
0000 0000
0000 0000
--00 0000
0000 0000
--00 0000
0000 0000
--00 0000
0000 0000
---- 0000
-101 0000
0000 0-00
0000 0000
-000 0000
1111 1111
0000 0000
PTCON1
PTMRL
PTMRH
PTPERL
PTPERH
PDC0L
PDC0H
PDC1L
PDC1H
PDC2L
PDC2H
PDC3L
PDC3H
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
uu-- ----
uuuu uuuu
---- uuuu
uuuu uuuu
---- uuuu
--uu uuuu
uuuu uuuu
uuuu uuuu
--uu uuuu
uuuu uuuu
--uu uuuu
uuuu uuuu
--uu uuuu
uuuu uuuu
---- uuuu
-uuu uuuu
uuuu u-uu
uuuu uuuu
-uuu uuuu
uuuu uuuu
uuuu uuuu
SEVTCMPL 2331 2431 4331 4431
SEVTCMPH 2331 2431 4331 4431
PWMCON0 2331 2431 4331 4431
PWMCON1 2331 2431 4331 4431
DTCON
2331 2431 4331 4431
FLTCONFIG 2331 2431 4331 4431
OVDCOND 2331 2431 4331 4431
OVDCONS
2331 2431 4331 4431
CAP1BUFH/ 2331 2431 4331 4431
VELRH
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
CAP1BUFL/ 2331 2431 4331 4431
VELRL
CAP2BUFH/ 2331 2431 4331 4431
POSCNTH
CAP2BUFL/ 2331 2431 4331 4431
POSCNTL
Legend: u= unchanged, x= unknown, -= unimplemented bit, read as ‘0’, q= value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 4-2 for Reset value for specific condition.
5: Bits 6 and 7 of PORTA, LATA and TRISA are enabled, depending on the Oscillator mode selected. When
not enabled as PORTA pins, they are disabled and read ‘0’.
6: Bit 3 of PORTE and LATE are enabled if MCLR functionality is disabled. When not enabled as the PORTE
pin, they are disabled and read as ‘0’. The 28-pin devices have only RE3 on PORTE when MCLR is
disabled.
DS39616B-page 52
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 4-3:
Register
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
MCLR Resets
WDT Reset
Power-on Reset,
Brown-out Reset
Wake-up via WDT
or Interrupt
Applicable Devices
RESET Instruction
Stack Resets
CAP3BUFH/ 2331 2431 4331 4431
MAXCNTH
xxxx xxxx
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
CAP3BUFL/ 2331 2431 4331 4431
MAXCNTL
CAP1CON
CAP2CON
CAP3CON
DFLTCON
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
2331 2431 4331 4431
-0-- 0000
-0-- 0000
-0-- 0000
-000 0000
-0-- 0000
-0-- 0000
-0-- 0000
-000 0000
-u-- uuuu
-u-- uuuu
-u-- uuuu
-uuu uuuu
Legend: u= unchanged, x= unknown, -= unimplemented bit, read as ‘0’, q= value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 4-2 for Reset value for specific condition.
5: Bits 6 and 7 of PORTA, LATA and TRISA are enabled, depending on the Oscillator mode selected. When
not enabled as PORTA pins, they are disabled and read ‘0’.
6: Bit 3 of PORTE and LATE are enabled if MCLR functionality is disabled. When not enabled as the PORTE
pin, they are disabled and read as ‘0’. The 28-pin devices have only RE3 on PORTE when MCLR is
disabled.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 53
PIC18F2331/2431/4331/4431
FIGURE 4-3:
TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD, VDD RISE < TPWRT)
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
OST TIME-OUT
TOST
INTERNAL RESET
FIGURE 4-4:
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
OST TIME-OUT
TOST
INTERNAL RESET
FIGURE 4-5:
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
OST TIME-OUT
TOST
INTERNAL RESET
DS39616B-page 54
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 4-6:
SLOW RISE TIME (MCLR TIED TO VDD, VDD RISE > TPWRT)
5V
1V
0V
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
FIGURE 4-7:
TIME-OUT SEQUENCE ON POR W/ PLL ENABLED (MCLR TIED TO VDD)
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
OST TIME-OUT
TOST
TPLL
PLL TIME-OUT
INTERNAL RESET
Note: TOST = 1024 clock cycles.
TPLL ≈ 2 ms max. First three stages of the PWRT timer.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 55
PIC18F2331/2431/4331/4431
NOTES:
DS39616B-page 56
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
5.1
Program Memory Organization
5.0
MEMORY ORGANIZATION
A 21-bit program counter is capable of addressing the
2-Mbyte program memory space. Accessing a location
between the physically implemented memory and the
2-Mbyte address will cause a read of all ‘0’s (a NOP
instruction).
There are three memory types in enhanced MCU
devices. These memory types are:
• Program Memory
• Data RAM
• Data EEPROM
The PIC18F2331 and PIC18F4331 each have
8 Kbytes of Flash memory and can store up to 4,096
single-word instructions.
Data and program memory use separate busses,
which allows for concurrent access of these types.
Additional detailed information for Flash program mem-
ory and data EEPROM is provided in Section 6.0
“Flash Program Memory” and Section 7.0 “Data
EEPROM Memory”, respectively.
The PIC18F2431 and PIC18F4431 each have
16 Kbytes of Flash memory and can store up to 8,192
single-word instructions.
The Reset vector address is at 000000h and the
interrupt vector addresses are at 000008h and
000018h.
The Program Memory Maps for PIC18F2X31 and
PIC18F4X31 devices are shown in Figure 5-1 and
Figure 5-2, respectively.
FIGURE 5-1:
PROGRAM MEMORY MAP
AND STACK FOR
FIGURE 5-2:
PROGRAM MEMORY MAP
AND STACK FOR
PIC18F2331/4331
PIC18F2431/4431
PC<20:0>
21
PC<20:0>
21
CALL,RCALL,RETURN
CALL,RCALL,RETURN
RETFIE,RETLW
RETFIE,RETLW
Stack Level 1
Stack Level 1
•
•
•
•
•
•
Stack Level 31
Stack Level 31
000000h
000000h
000008h
000018h
Reset Vector LSb
Reset Vector LSb
000008h
000018h
High Priority Interrupt Vector LSb
Low Priority Interrupt Vector LSb
High Priority Interrupt Vector LSb
Low Priority Interrupt Vector LSb
On-Chip Flash
Program Memory
001FFFh
002000h
On-Chip Flash
Program Memory
003FFFh
004000h
Unused -
Read ‘0’s
Unused -
Read ‘0’s
1FFFFFh
1FFFFFh
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 57
PIC18F2331/2431/4331/4431
5.2.2
RETURN STACK POINTER
(STKPTR)
5.2
Return Address Stack
The return address stack allows any combination of up
to 31 program calls and interrupts to occur. The PC
(Program Counter) is pushed onto the stack when a
CALLor RCALLinstruction is executed, or an interrupt
is acknowledged. The PC value is pulled off the stack
on a RETURN, RETLW or a RETFIE instruction.
PCLATU and PCLATH are not affected by any of the
RETURNor CALLinstructions.
The STKPTR register (Register 5-1) contains the stack
pointer value, the STKFUL (stack full) status bit, and
the STKUNF (stack underflow) status bits. The value of
the stack pointer can be 0 through 31. The stack pointer
increments before values are pushed onto the stack
and decrements after values are popped off the stack.
At Reset, the stack pointer value will be zero. The user
may read and write the stack pointer value. This feature
can be used by a Real-Time Operating System for
return stack maintenance.
The stack operates as a 31-word by 21-bit RAM and a
5-bit stack pointer, with the stack pointer initialized to
00000b after all Resets. There is no RAM associated
with stack pointer 00000b. This is only a Reset value.
During a CALLtype instruction, causing a push onto the
stack, the stack pointer is first incremented and the
RAM location pointed to by the stack pointer is written
with the contents of the PC (already pointing to the
instruction following the call). During a RETURN type
instruction, causing a pop from the stack, the contents
of the RAM location pointed to by the STKPTR are
transferred to the PC and then the stack pointer is
decremented.
After the PC is pushed onto the stack 31 times (without
popping any values off the stack), the STKFUL bit is
set. The STKFUL bit is cleared by software or by a
POR.
The action that takes place when the stack becomes
full depends on the state of the STVREN (Stack Over-
flow Reset Enable) configuration bit. (Refer to
Section 22.1 “Configuration Bits” for a description of
the device configuration bits.) If STVREN is set
(default), the 31st push will push the (PC + 2) value
onto the stack, set the STKFUL bit, and reset the
device. The STKFUL bit will remain set and the stack
pointer will be set to zero.
The stack space is not part of either program or data
space. The stack pointer is readable and writable, and
the address on the top of the stack is readable and writ-
able through the top-of-stack Special File registers.
Data can also be pushed to, or popped from, the stack
using the top-of-stack SFRs. Status bits indicate if the
stack is full, has overflowed or underflowed.
If STVREN is cleared, the STKFUL bit will be set on the
31st push and the stack pointer will increment to 31.
Any additional pushes will not overwrite the 31st push,
and STKPTR will remain at 31.
When the stack has been popped enough times to
unload the stack, the next pop will return a value of zero
to the PC and set the STKUNF bit, while the stack
pointer remains at zero. The STKUNF bit will remain
set until cleared by software or a POR occurs.
5.2.1
TOP-OF-STACK ACCESS
The top of the stack is readable and writable. Three
register locations, TOSU, TOSH and TOSL hold the
contents of the stack location pointed to by the
STKPTR register (Figure 5-3). This allows users to
implement a software stack if necessary. After a CALL,
RCALLor interrupt, the software can read the pushed
value by reading the TOSU, TOSH and TOSL registers.
These values can be placed on a user-defined software
stack. At return time, the software can replace the
TOSU, TOSH and TOSL and do a return.
Note:
Returning a value of zero to the PC on an
underflow has the effect of vectoring the
program to the Reset vector, where the
stack conditions can be verified and
appropriate actions can be taken. This is
not the same as a Reset, as the contents
of the SFRs are not affected.
The user must disable the global interrupt enable bits
while accessing the stack to prevent inadvertent stack
corruption.
FIGURE 5-3:
RETURN ADDRESS STACK AND ASSOCIATED REGISTERS
Return Address Stack
11111
11110
11101
STKPTR<4:0>
TOSU
00h
TOSH
1Ah
TOSL
34h
00010
00011
001A34h 00010
000D58h 00001
00000
Top-of-Stack
DS39616B-page 58
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
REGISTER 5-1:
STKPTR REGISTER
R/C-0 R/C-0
U-0
—
R/W-0
SP4
R/W-0
SP3
R/W-0
SP2
R/W-0
SP1
R/W-0
SP0
STKFUL STKUNF
bit 7
bit 0
bit 7(1)
bit 6(1)
STKFUL: Stack Full Flag bit
1= Stack became full or overflowed
0= Stack has not become full or overflowed
STKUNF: Stack Underflow Flag bit
1= Stack underflow occurred
0= Stack underflow did not occur
bit 5
Unimplemented: Read as ‘0’
bit 4-0
SP4:SP0: Stack Pointer Location bits
Note 1: Bit 7 and bit 6 are cleared by user software or by a POR.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented
‘0’ = Bit is cleared
C = Clearable only bit
x = Bit is unknown
- n = Value at POR
5.2.3
PUSHAND POPINSTRUCTIONS
5.2.4
STACK FULL/UNDERFLOW RESETS
Since the Top-of-Stack (TOS) is readable and writable,
the ability to push values onto the stack and pull values
off the stack without disturbing normal program execu-
tion is a desirable option. To push the current PC value
onto the stack, a PUSH instruction can be executed.
This will increment the stack pointer and load the cur-
rent PC value onto the stack. TOSU, TOSH and TOSL
can then be modified to place data or a return address
on the stack.
These Resets are enabled by programming the
STVREN bit in Configuration Register 4L. When the
STVREN bit is cleared, a full or underflow condition will
set the appropriate STKFUL or STKUNF bit, but not
cause a device Reset. When the STVREN bit is set, a
full or underflow will set the appropriate STKFUL or
STKUNF bit and then cause a device Reset. The
STKFUL or STKUNF bits are cleared by the user
software or a POR Reset.
The ability to pull the TOS value off of the stack and
replace it with the value that was previously pushed
onto the stack, without disturbing normal execution, is
achieved by using the POPinstruction. The POPinstruc-
tion discards the current TOS by decrementing the
stack pointer. The previous value pushed onto the
stack then becomes the TOS value.
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5.3
Fast Register Stack
5.4
PCL, PCLATH and PCLATU
A “fast return” option is available for interrupts. A fast
register stack is provided for the Status, WREG and
BSR registers and are only one in depth. The stack is
not readable or writable and is loaded with the current
value of the corresponding register when the processor
vectors for an interrupt. The values in the registers are
then loaded back into the working registers, if the
RETFIE, FASTinstruction is used to return from the
interrupt.
The program counter (PC) specifies the address of the
instruction to fetch for execution. The PC is 21-bits
wide. The low byte, known as the PCL register, is both
readable and writable. The high byte, or PCH register,
contains the PC<15:8> bits and is not directly readable
or writable. Updates to the PCH register may be per-
formed through the PCLATH register. The upper byte is
called PCU. This register contains the PC<20:16> bits
and is not directly readable or writable. Updates to the
PCU register may be performed through the PCLATU
register.
All interrupt sources will push values into the stack reg-
isters. If both low and high priority interrupts are
enabled, the stack registers cannot be used reliably to
return from low priority interrupts. If a high priority inter-
rupt occurs while servicing a low priority interrupt, the
stack register values stored by the low priority interrupt
will be overwritten. Users must save the key registers
in software during a low priority interrupt.
The contents of PCLATH and PCLATU will be trans-
ferred to the program counter by any operation that
writes PCL. Similarly, the upper two bytes of the pro-
gram counter will be transferred to PCLATH and
PCLATU by an operation that reads PCL. This is useful
for computed offsets to the PC (see Section 5.8.1
“Computed GOTO”).
If interrupt priority is not used, all interrupts may use the
fast register stack for returns from interrupt.
The PC addresses bytes in the program memory. To
prevent the PC from becoming misaligned with word
instructions, the LSB of PCL is fixed to a value of ‘0’.
The PC increments by 2 to address sequential
instructions in the program memory.
If no interrupts are used, the fast register stack can be
used to restore the Status, WREG and BSR registers at
the end of a subroutine call. To use the fast register
stack for a subroutine call, a CALL label, FAST
instruction must be executed to save the Status,
WREG and BSR registers to the fast register stack. A
RETURN, FASTinstruction is then executed to restore
these registers from the fast register stack.
The CALL, RCALL, GOTO and program branch
instructions write to the program counter directly. For
these instructions, the contents of PCLATH and
PCLATU are not transferred to the program counter.
Example 5-1 shows a source code example that uses
the fast register stack during a subroutine call and
return.
EXAMPLE 5-1:
FAST REGISTER STACK
CODE EXAMPLE
CALL SUB1, FAST
;STATUS, WREG, BSR
;SAVED IN FAST REGISTER
;STACK
•
•
SUB1
•
•
RETURN FAST
;RESTORE VALUES SAVED
;IN FAST REGISTER STACK
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5.5
Clocking Scheme/Instruction
Cycle
5.6
Instruction Flow/Pipelining
An “Instruction Cycle” consists of four Q cycles (Q1,
Q2, Q3 and Q4). The instruction fetch and execute are
pipelined such that fetch takes one instruction cycle,
while decode and execute takes another instruction
cycle. However, due to the pipelining, each instruction
effectively executes in one cycle. If an instruction
causes the program counter to change (e.g., GOTO),
then two cycles are required to complete the instruction
(Example 5-2).
The clock input (from OSC1) is internally divided by
four to generate four non-overlapping quadrature
clocks, namely Q1, Q2, Q3 and Q4. Internally, the pro-
gram counter (PC) is incremented every Q1, the
instruction is fetched from the program memory and
latched into the Instruction register in Q4. The instruc-
tion is decoded and executed during the following Q1
through Q4. The clocks and instruction execution flow
are shown in Figure 5-4.
A fetch cycle begins with the program counter (PC)
incrementing in Q1.
In the execution cycle, the fetched instruction is latched
into the “Instruction register” (IR) in cycle Q1. This
instruction is then decoded and executed during the
Q2, Q3, and Q4 cycles. Data memory is read during Q2
(operand read) and written during Q4 (destination
write).
FIGURE 5-4:
CLOCK/INSTRUCTION CYCLE
Q2
Q3
Q4
Q2
Q3
Q4
Q2
Q3
Q4
Q1
Q1
Q1
OSC1
Q1
Q2
Q3
Internal
Phase
Clock
Q4
PC
PC+2
PC
PC+4
OSC2/CLKO
(RC mode)
Execute INST (PC-2)
Fetch INST (PC)
Execute INST (PC)
Fetch INST (PC+2)
Execute INST (PC+2)
Fetch INST (PC+4)
EXAMPLE 5-2:
INSTRUCTION PIPELINE FLOW
TCY0
TCY1
TCY2
TCY3
TCY4
TCY5
1. MOVLW 55h
2. MOVWF PORTB
3. BRA SUB_1
Fetch 1
Execute 1
Fetch 2
Execute 2
Fetch 3
Execute 3
Fetch 4
4. BSF
PORTA, BIT3 (Forced NOP)
Flush (NOP)
5. Instruction @ address SUB_1
Fetch SUB_1 Execute SUB_1
All instructions are single cycle, except for any program branches. These take two cycles since the fetch instruction
is “flushed” from the pipeline, while the new instruction is being fetched and then executed.
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The CALLand GOTOinstructions have the absolute pro-
gram memory address embedded into the instruction.
Since instructions are always stored on word bound-
aries, the data contained in the instruction is a word
address. The word address is written to PC<20:1>,
which accesses the desired byte address in program
memory. Instruction #2 in Figure 5-5 shows how the
instruction ‘GOTO 000006h’ is encoded in the program
memory. Program branch instructions, which encode a
relative address offset, operate in the same manner.
The offset value stored in a branch instruction repre-
sents the number of single-word instructions that the
PC will be offset by. Section 23.0 “Instruction Set
Summary” provides further details of the instruction
set.
5.7
Instructions in Program Memory
The program memory is addressed in bytes. Instruc-
tions are stored as two bytes or four bytes in program
memory. The Least Significant Byte of an instruction
word is always stored in a program memory location
with an even address (LSB = 0). Figure 5-5 shows an
example of how instruction words are stored in the pro-
gram memory. To maintain alignment with instruction
boundaries, the PC increments in steps of 2 and the
LSB will always read ‘0’ (see Section 5.4 “PCL,
PCLATH and PCLATU”).
FIGURE 5-5:
INSTRUCTIONS IN PROGRAM MEMORY
Word Address
LSB = 1
LSB = 0
↓
Program Memory
Byte Locations →
000000h
000002h
000004h
000006h
000008h
00000Ah
00000Ch
00000Eh
000010h
000012h
000014h
Instruction 1:
Instruction 2:
0Fh
EFh
F0h
C1h
F4h
55h
03h
00h
23h
56h
MOVLW
GOTO
055h
000006h
Instruction 3:
MOVFF
123h, 456h
the second word of the instruction is executed by itself
(first word was skipped), it will execute as a NOP. This
action is necessary when the two-word instruction is
preceded by a conditional instruction that results in a
skip operation. A program example that demonstrates
this concept is shown in Example 5-3. Refer to
Section 23.0 “Instruction Set Summary” for further
details of the instruction set.
5.7.1
TWO-WORD INSTRUCTIONS
PIC18F2331/2431/4331/4431 devices have four two-
word instructions: MOVFF,CALL,GOTOand LFSR. The
second word of these instructions has the 4 MSBs set
to ‘1’s and is decoded as a NOPinstruction. The lower
12 bits of the second word contain data to be used by
the instruction. If the first word of the instruction is
executed, the data in the second word is accessed. If
EXAMPLE 5-3:
TWO-WORD INSTRUCTIONS
Source Code
CASE 1:
Object Code
0110 0110 0000 0000 TSTFSZ
REG1
; is RAM location 0?
1100 0001 0010 0011
1111 0100 0101 0110
0010 0100 0000 0000
MOVFF
ADDWF
REG1, REG2 ; No, skip this word
; Execute this word as a NOP
; continue code
REG3
CASE 2:
Object Code
Source Code
TSTFSZ
0110 0110 0000 0000
1100 0001 0010 0011
1111 0100 0101 0110
0010 0100 0000 0000
REG1
; is RAM location 0?
MOVFF
REG1, REG2 ; Yes, execute this word
; 2nd word of instruction
ADDWF
REG3
; continue code
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5.8
Look-up Tables
5.9
Data Memory Organization
Look-up tables are implemented two ways:
The data memory is implemented as static RAM. Each
register in the data memory has a 12-bit address,
allowing up to 4096 bytes of data memory. Figure 5-6
shows the data memory organization for the
PIC18F2331/2431/4331/4431 devices.
• Computed GOTO
• Table Reads
5.8.1
COMPUTED GOTO
The data memory map is divided into as many as 16
banks that contain 256 bytes each. The lower 4 bits of
the Bank Select Register (BSR<3:0>) select which
bank will be accessed. The upper 4 bits for the BSR are
not implemented.
A computed GOTOis accomplished by adding an offset
to the program counter. An example is shown in
Example 5-4.
A look-up table can be formed with an ADDWF PCL
instruction and a group of RETLW 0xnn instructions.
WREG is loaded with an offset into the table before
executing a call to that table. The first instruction of the
called routine is the ADDWF PCLinstruction. The next
instruction executed will be one of the RETLW 0xnn
instructions, which returns the value 0xnnto the calling
function.
The data memory contains Special Function Registers
(SFR) and General Purpose Registers (GPR). The
SFRs are used for control and status of the controller
and peripheral functions, while GPRs are used for data
storage and scratch pad operations in the user’s
application. The SFRs start at the last location of Bank
15 (FFFh) and extend to F60h. Any remaining space
beyond the SFRs in the bank may be implemented as
GPRs. GPRs start at the first location of Bank 0 and
grow upwards. Any read of an unimplemented location
will read as ‘0’s.
The offset value (in WREG) specifies the number of
bytes that the program counter should advance, and
should be multiples of 2 (LSB = 0).
In this method, only one data byte may be stored in
each instruction location and room on the return
address stack is required.
The entire data memory may be accessed directly or
indirectly. Direct addressing may require the use of the
BSR register. Indirect addressing requires the use of a
File Select Register (FSRn) and a corresponding
Indirect File Operand (INDFn). Each FSR holds a 12-
bit address value that can be used to access any
location in the Data Memory map without banking. See
Section 5.12 “Indirect Addressing, INDF and FSR
Registers” for indirect addressing details.
EXAMPLE 5-4:
COMPUTED GOTO USING
AN OFFSET VALUE
MOVFWOFFSET
CALLTABLE
ORG 0xnn00
TABLEADDWFPCL
RETLW0xnn
RETLW0xnn
RETLW0xnn
.
The instruction set and architecture allow operations
across all banks. This may be accomplished by indirect
addressing or by the use of the MOVFFinstruction. The
MOVFF instruction is a two-word/two-cycle instruction
that moves a value from one register to another.
.
.
To ensure that commonly used registers (SFRs and
select GPRs) can be accessed in a single cycle,
regardless of the current BSR values, an Access Bank
is implemented. A segment of Bank 0 and a segment of
Bank 15 comprise the Access RAM. Section 5.10
“Access Bank” provides a detailed description of the
Access RAM.
5.8.2
TABLE READS/TABLE WRITES
A better method of storing data in program memory
allows two bytes of data to be stored in each instruction
location.
Look-up table data may be stored two bytes per pro-
gram word by using table reads and writes. The table
pointer (TBLPTR) specifies the byte address and the
table latch (TABLAT) contains the data that is read
from, or written to program memory. Data is transferred
to/from program memory, one byte at a time.
5.9.1
GENERAL PURPOSE REGISTER
FILE
Enhanced MCU devices may have banked memory in
the GPR area. GPRs are not initialized by a Power-on
Reset and are unchanged on all other Resets.
The Table Read/Table Write operation is discussed
further in Section 6.1 “Table Reads and Table
Writes”.
Data RAM is available for use as GPR registers by all
instructions. The second half of Bank 15 (F60h to
FFFh) contains SFRs. All other banks of data memory
contain GPRs, starting with Bank 0.
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FIGURE 5-6:
DATA MEMORY MAP FOR PIC18F2331/2431/4331/4431 DEVICES
BSR<3:0>
Data Memory Map
000h
05Fh
060h
0FFh
100h
00h
Access RAM
GPR
= 0000
= 0001
Bank 0
Bank 1
Bank 2
FFh
00h
GPR
GPR
1FFh
200h
FFh
00h
= 0010
FFh
00h
2FFh
300h
Access Bank
00h
Access RAM Low
5Fh
60h
= 0011
= 1110
Access RAM High
(SFRs)
Bank 3
to
Bank 14
Unused
Read ‘00h’
FFh
When a = 0:
The BSR is ignored and the
Access Bank is used.
The first 96 bytes are
General Purpose RAM
(from Bank 0).
EFFh
F00h
F5Fh
F60h
FFFh
00h
FFh
Unused
SFR
= 1111
The second 160 bytes are
Special Function Registers
(from Bank 15).
Bank 15
When a = 1:
The BSR specifies the bank
used by the instruction.
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“core” are described in this section, while those related
to the operation of the peripheral features are
described in the section of that peripheral feature.
5.9.2
SPECIAL FUNCTION REGISTERS
The Special Function Registers (SFRs) are registers
used by the CPU and Peripheral Modules for control-
ling the desired operation of the device. These regis-
ters are implemented as static RAM. A list of these
registers is given in Table 5-1 and Table 5-2.
The SFRs are typically distributed among the
peripherals whose functions they control.
The unused SFR locations will be unimplemented and
read as ‘0’s.
The SFRs can be classified into two sets; those asso-
ciated with the “core” function and those related to the
peripheral functions. Those registers related to the
TABLE 5-1:
SPECIAL FUNCTION REGISTER MAP FOR PIC18F2331/2431/4331/4431 DEVICES
Address
Name
Address
Name
Address
Name
Address
Name
Address
Name
FFFh
FFEh
FFDh
TOSU
TOSH
TOSL
FDFh
INDF2
FBFh
FBEh
CCPR1H
CCPR1L
F9Fh
F9Eh
F9Dh
F9Ch
IPR1
PIR1
PIE1
—
F7Fh
F7Eh
F7Dh
F7Ch
F7Bh
F7Ah
F79h
F78h
F77h
F76h
F75h
F74h
F73h
F72h
F71h
F70h
F6Fh
F6Eh
F6Dh
F6Ch
F6Bh
F6Ah
F69h
F68h
F67h
F66h
F65h
F64h
F63h
F62h
F61h
F60h
PTCON0
PTCON1
PTMRL
FDEh POSTINC2
FDDh POSTDEC2
FDCh PREINC2
FBDh CCP1CON
FFCh STKPTR
FBCh
FBBh
CCPR2H
CCPR2L
PTMRH
FFBh
FFAh
FF9h
PCLATU
PCLATH
PCL
FDBh
FDAh
FD9h
FD8h
FD7h
FD6h
FD5h
FD4h
PLUSW2
FSR2H
FSR2L
STATUS
TMR0H
TMR0L
T0CON
—
F9Bh OSCTUNE
PTPERL
FBAh CCP2CON
F9Ah
F99h
F98h
F97h
F96h
F95h
F94h
F93h
F92h
F91h
F90h
F8Fh
F8Eh
F8Dh
F8Ch
F8Bh
F8Ah
F89h
F88h
F87h
F86h
F85h
F84h
F83h
F82h
F81h
F80h
ADCON3
ADCHS
—
PTPERH
PDC0L
FB9h
FB8h
FB7h
FB6h
FB5h
FB4h
FB3h
FB2h
FB1h
FB0h
FAFh
FAEh
FADh
FACh
FABh
FAAh
FA9h
FA8h
FA7h
FA6h
FA5h
FA4h
FA3h
FA2h
FA1h
FA0h
ANSEL1
ANSEL0
T5CON
FF8h TBLPTRU
FF7h TBLPTRH
FF6h TBLPTRL
PDC0H
—
PDC1L
QEICON
—
TRISE
TRISD
TRISC
TRISB
TRISA
PR5H
PR5L
—
PDC1H
FF5h
FF4h
FF3h
FF2h
TABLAT
PRODH
PRODL
INTCON
PDC2L
—
—
PDC2H
FD3h OSCCON
FD2h LVDCON
FD1h WDTCON
PDC3L
—
PDC3H
FF1h INTCON2
FF0h INTCON3
—
SEVTCMPL
SEVTCMPH
PWMCON0
PWMCON1
DTCON
FD0h
FCFh
FCEh
FCDh
FCCh
FCBh
FCAh
FC9h
FC8h
RCON
TMR1H
TMR1L
T1CON
TMR2
SPBRGH
SPBRG
RCREG
TXREG
TXSTA
RCSTA
BAUDCTL
EEADR
EEDATA
EECON2
EECON1
IPR3
FEFh
INDF0
FEEh POSTINC0
FEDh POSTDEC0
FECh PREINC0
—
LATE
LATD
LATC
LATB
FLTCONFIG
OVDCOND
OVDCONS
CAP1BUFH
CAP1BUFL
CAP2BUFH
CAP2BUFL
CAP3BUFH
CAP3BUFL
CAP1CON
CAP2CON
CAP3CON
DFLTCON
FEBh
FEAh
FE9h
FE8h
FE7h
PLUSW0
FSR0H
FSR0L
WREG
INDF1
PR2
T2CON
SSPBUF
SSPADD
LATA
TMR5H
TMR5L
—
FC7h SSPSTAT
FC6h SSPCON
FE6h POSTINC1
FE5h POSTDEC1
FE4h PREINC1
FC5h
FC4h
FC3h
FC2h
FC1h
FC0h
—
—
ADRESH
ADRESL
ADCON0
ADCON1
ADCON2
PIR3
PORTE
PORTD
PORTC
PORTB
PORTA
FE3h
FE2h
FE1h
FE0h
PLUSW1
FSR1H
FSR1L
BSR
PIE3
IPR2
PIR2
PIE2
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PIC18F2331/2431/4331/4431
TABLE 5-2:
File Name
TOSU
REGISTER FILE SUMMARY (PIC18F2331/2431/4331/4431)
Value on
POR, BOR
Details on
page:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
—
—
—
Top-of-Stack Upper Byte (TOS<20:16>)
---0 0000
0000 0000
0000 0000
00-0 0000
---0 0000
0000 0000
0000 0000
--00 0000
0000 0000
0000 0000
0000 0000
xxxx xxxx
xxxx xxxx
0000 000x
48, 58
48, 58
48, 58
48, 59
48, 60
48, 60
48, 60
48, 78
48, 78
48, 78
48, 78
48, 89
48, 89
48, 93
TOSH
Top-of-Stack High Byte (TOS<15:8>)
Top-of-Stack Low Byte (TOS<7:0>)
TOSL
STKPTR
PCLATU
PCLATH
PCL
STKFUL
—
STKUNF
—
—
bit 21(3)
Return Stack Pointer
Holding register for PC<20:16>
Holding register for PC<15:8>
PC Low Byte (PC<7:0>)
TBLPTRU
TBLPTRH
TBLPTRL
TABLAT
PRODH
PRODL
INTCON
—
—
bit 21(3)
Program Memory Table Pointer Upper Byte (TBLPTR<20:16>)
Program Memory Table Pointer High Byte (TBLPTR<15:8>)
Program Memory Table Pointer Low Byte (TBLPTR<7:0>)
Program Memory Table Latch
Product register High Byte
Product register Low Byte
GIE/GIEH PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0F
RBIF
INTCON2
INTCON3
INDF0
RBPU
INT2P
INTEDG0
INT1P
INTEDG1
—
INTEDG2
INT2IE
—
TMR0IP
—
—
RBIP
1111 -1-1
11-0 0-00
N/A
48, 94
48, 95
48, 71
48, 71
48, 71
48, 71
48, 71
48, 71
48, 71
48
INT1IE
INT2IF
INT1IF
Uses contents of FSR0 to address data memory – value of FSR0 not changed (not a physical register)
Uses contents of FSR0 to address data memory – value of FSR0 post-incremented (not a physical register)
POSTINC0
N/A
POSTDEC0 Uses contents of FSR0 to address data memory – value of FSR0 post-decremented (not a physical register)
N/A
PREINC0
PLUSW0
FSR0H
Uses contents of FSR0 to address data memory – value of FSR0 pre-incremented (not a physical register)
Uses contents of FSR0 to address data memory – value of FSR0 offset by W (not a physical register)
N/A
N/A
—
—
—
—
Indirect Data Memory Address Pointer 0 High
---- 0000
xxxx xxxx
xxxx xxxx
N/A
FSR0L
Indirect Data Memory Address Pointer 0 Low Byte
Working register
WREG
INDF1
Uses contents of FSR1 to address data memory – value of FSR1 not changed (not a physical register)
Uses contents of FSR1 to address data memory – value of FSR1 post-incremented (not a physical register)
48, 71
48, 71
48, 71
48, 71
48, 71
49, 71
49, 71
49, 70
49, 71
49, 71
49, 71
49, 71
49, 71
49, 71
49, 71
49, 73
49, 135
49, 135
49, 133
POSTINC1
N/A
POSTDEC1 Uses contents of FSR1 to address data memory – value of FSR1 post-decremented (not a physical register)
N/A
PREINC1
PLUSW1
FSR1H
FSR1L
Uses contents of FSR1 to address data memory – value of FSR1 pre-incremented (not a physical register)
Uses contents of FSR1 to address data memory – value of FSR1 offset by W (not a physical register)
N/A
N/A
—
—
—
—
Indirect Data Memory Address Pointer 1 High
---- 0000
xxxx xxxx
---- 0000
N/A
Indirect Data Memory Address Pointer 1 Low Byte
BSR
—
—
—
—
Bank Select Register
INDF2
Uses contents of FSR2 to address data memory – value of FSR2 not changed (not a physical register)
Uses contents of FSR2 to address data memory – value of FSR2 post-incremented (not a physical register)
POSTINC2
N/A
POSTDEC2 Uses contents of FSR2 to address data memory – value of FSR2 post-decremented (not a physical register)
N/A
PREINC2
PLUSW2
FSR2H
FSR2L
Uses contents of FSR2 to address data memory – value of FSR2 pre-incremented (not a physical register)
Uses contents of FSR2 to address data memory – value of FSR2 offset by W (not a physical register)
N/A
N/A
—
—
—
—
Indirect Data Memory Address Pointer 2 High
---- 0000
xxxx xxxx
---x xxxx
0000 0000
xxxx xxxx
11-- 1111
Indirect Data Memory Address Pointer 2 Low Byte
STATUS
TMR0H
TMR0L
T0CON
—
—
—
N
OV
Z
DC
C
Timer0 register High Byte
Timer0 register Low Byte
TMR0ON
T016BIT
—
—
T0PS3
T0PS2
T0PS1
T0PS0
Legend:
Note 1:
x= unknown, u= unchanged, – = unimplemented, q= value depends on condition
RA6 and associated bits are configured as port pins in RCIO, ECIO and INTIO2 (with port function on RA6) Oscillator mode only, and read
‘0’ in all other oscillator modes.
2:
3:
4:
RA7 and associated bits are configured as port pins in INTIO2 Oscillator mode only and read ‘0’ in all other modes.
Bit 21 of the PC is only available in Test mode and serial programming modes.
If PBADEN = 0, PORTB<4:0> are configured as digital input and read unknown, and if PBADEN = 1, PORTB<4:0> are configured as
analog input and read ‘0’ following a Reset.
5:
6:
These registers and/or bits are not implemented on the PIC18F2X31 devices, and read as ‘0’.
The RE3 port bit is only available when MCLRE fuse (CONFIG3H<7>) is programmed to ‘0’. Otherwise, RE3 reads ‘0’. This bit is read-only.
DS39616B-page 66
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 5-2:
REGISTER FILE SUMMARY (PIC18F2331/2431/4331/4431) (CONTINUED)
Value on
POR, BOR
Details on
page:
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
OSCCON
LVDCON
WDTCON
IDLEN
—
IRCF2
—
IRCF1
IVRST
IRCF0
OSTS
LVDL3
IOFS
SCS1
SCS0
0000 q000
--00 0101
28, 49
49, 263
49, 279
LVDEN
LVDL2
LVDL1
LVDL0
WDTW
SWDTEN 0000 0000
—
—
—
—
—
RI
—
—
—
RCON
IPEN
TO
PD
POR
BOR
0--1 11qq 47, 74, 105
TMR1H
TMR1L
Timer1 register High Byte
Timer1 register Low Byte
xxxx xxxx
xxxx xxxx
49, 141
49, 141
T1CON
TMR2
RD16
T1RUN
T1CKPS1
T1CKPS0 T1OSCEN
T1SYNC
TMR2ON
TMR1CS
T2CKPS1
TMR1ON
0000 0000
0000 0000
1111 1111
49, 137
49, 143
49, 143
49, 143
49, 220
49, 220
Timer2 register
PR2
Timer2 Period register
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0
SSP Receive Buffer/Transmit register
SSP Address register in I2C Slave mode. SSP Baud Rate Reload register in I2C Master mode.
T2CON
SSPBUF
SSPADD
—
T2CKPS0 -000 0000
xxxx xxxx
0000 0000
SSPSTAT
SSPCON
ADRESH
ADRESL
SMP
CKE
D/A
P
S
R/W
UA
BF
0000 0000
0000 0000
xxxx xxxx
xxxx xxxx
49, 212
49, 213
50, 259
50, 259
WCOL
SSPOV
SSPEN
CKP
SSPM3
SSPM2
SSPM1
SSPM0
A/D Result register High Byte
A/D Result register Low Byte
ADCON0
ADCON1
—
—
ACONV
—
ACSCH
FIFOEN
ACMOD1
BFEMT
ACMOD0
FFOVFL
GO/DONE
ADPNT1
ADON
--00 0000
00-0 1000
50, 244
50, 245
VCFG1
VCFG0
ADPNT0
50, 246
ADCON2
ADCON3
ADCSH
ADFM
ADRS1
GDSEL1
ACQT3
ADRS0
GDSEL0
ACQT2
—
ACQT1
SSRC4
GBSEL0
ACQT0
SSRC3
GCSEL1
ADCS2
SSRC2
GCSEL0
ADCS1
SSRC1
GASEL1
ADCS0
SSRC0
GASEL0
0000 0000
00-0 0000
0000 0000
xxxx xxxx
xxxx xxxx
0000 0000
51. 247
51, 248
50, 152
50, 152
GBSEL1
CCPR1H
CCPR1L
CCP1CON
Capture/Compare/PWM register1 High Byte
Capture/Compare/PWM register1 Low Byte
—
—
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M1
CCP1M0
50, 155,
149
CCPR2H
CCPR2L
CCP2CON
Capture/Compare/PWM register2 High Byte
Capture/Compare/PWM register2 Low Byte
xxxx xxxx
xxxx xxxx
--00 0000
50, 152
50, 152
50, 155
50, 249
—
—
—
DC2B1
—
DC2B0
—
CCP2M3
—
CCP2M2
—
CCP2M1
—
CCP2M0
ANS8
ANSEL1
—
---- ---1
1111 1111
0100 0000
0000 0000
ANS7(6)
T5SEN
ANS6(6)
RESEN(5)
ERROR
ANS5(6)
T5MOD
UP/DOWN
ANS4
T5PS1
QEIM2
ANS3
T5PS0
QEIM1
ANS2
ANS1
ANS0
50, 249
50, 145
50, 171
50, 225
50, 225
ANSEL0
T5CON
T5SYNC
QEIM0
TMR5CS
PDEC1
TMR5ON
PDEC0
QEICON
VELM
SPBRGH
SPBRG
RCREG
Baud Rate Generator register, High Byte
USART Baud Rate Generator
USART Receive register
0000 0000
0000 0000
0000 0000
50, 233,
232
TXREG
USART Transmit register
0000 0000
50, 230,
232
TXSTA
CSRC
SPEN
—
TX9
RX9
TXEN
SREN
—
SYNC
CREN
SCKP
—
BRGH
FERR
—
TRMT
OERR
WUE
TX9D
RX9D
0000 -010
0000 000x
-1-1 0-00
50, 222
50, 223
50, 224
RCSTA
ADEN
BRG16
BAUDCTL
RCIDL
ABDEN
Legend:
Note 1:
x= unknown, u= unchanged, – = unimplemented, q= value depends on condition
RA6 and associated bits are configured as port pins in RCIO, ECIO and INTIO2 (with port function on RA6) Oscillator mode only, and read
‘0’ in all other oscillator modes.
2:
3:
4:
RA7 and associated bits are configured as port pins in INTIO2 Oscillator mode only and read ‘0’ in all other modes.
Bit 21 of the PC is only available in Test mode and serial programming modes.
If PBADEN = 0, PORTB<4:0> are configured as digital input and read unknown, and if PBADEN = 1, PORTB<4:0> are configured as
analog input and read ‘0’ following a Reset.
5:
6:
These registers and/or bits are not implemented on the PIC18F2X31 devices, and read as ‘0’.
The RE3 port bit is only available when MCLRE fuse (CONFIG3H<7>) is programmed to ‘0’. Otherwise, RE3 reads ‘0’. This bit is read-only.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 67
PIC18F2331/2431/4331/4431
TABLE 5-2:
REGISTER FILE SUMMARY (PIC18F2331/2431/4331/4431) (CONTINUED)
Value on
POR, BOR
Details on
page:
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
EEADR
EEPROM Address register
EEPROM Data register
0000 0000
0000 0000
50, 85
50, 88
EEDATA
EECON2
EECON1
EEPROM Control register2 (not a physical register)
0000 0000 50, 76, 85
xx-0 x000 50, 77, 86
EEPGD
—
CFGS
—
—
—
—
FREE
PTIP
WRERR
WREN
WR
RD
50
IC3DRIP IC2QEIP
IC3DRIF IC2QEIF
IC3DRIE IC2QEIE
IC1IP
TMR5IP
IPR3
PIR3
---1 1111
—
—
50
PTIF
PTIE
IC1IF
IC1IE
TMR5IF
TMR5IE
—
---0 0000
50
PIE3
IPR2
PIR2
PIE2
—
—
—
—
—
—
—
—
---0 0000
OSFIP
OSFIF
OSFIE
—
EEIP
EEIF
EEIE
—
—
—
LVDIP
LVDIF
LVDIE
—
—
—
CCP2IP
CCP2IF
CCP2IE
1--1 -1-1
0--0 -0-0
0--0 -0-0
51, 103
51, 97
51, 100
IPR1
PIR1
ADIP
ADIF
RCIP
RCIF
TXIP
TXIF
SSPIP
SSPIF
CCP1IP
CCP1IF
TMR2IP
TMR2IF
TMR1IP
TMR1IF
-111 1111
-000 0000
51, 102
51, 96
—
—
PIE1
ADIE
—
RCIE
TUN5
TXIE
SSPIE
TUN3
CCP1IE
TUN2
TMR2IE
TUN1
TMR1IE
TUN0
-000 0000
--00 0000
51, 99
25, 51
50
OSCTUNE
—
TUN4
ADCON3
ADCHS
ADRS1
ADRS0
—
SSRC4
SSRC3
GCSEL1
—
SSRC2
SSRC1
SSRC0
00-0 0000
0000 0000
---- -111
50
GDSEL1
—
GDSEL0
—
GBSEL1
—
GBSEL0
—
GCSEL0
GASEL1
GASEL0
TRISE(5)
Data Direction bits for PORTE(5)
51, 131
TRISD(5)
TRISC
Data Direction Control register for PORTD
Data Direction Control register for PORTC
Data Direction Control register for PORTB
1111 1111
1111 1111
1111 1111
51, 128
51, 123
51, 117
TRISB
TRISA
PR5H
PR5L
TRISA7(2)
TRISA6(1) Data Direction Control register for PORTA
1111 1111
1111 1111
1111 1111
---- -xxx
51, 111
50
Timer5 Period register High Byte
Timer5 Period register Low Byte
50
LATE(5)
—
—
—
—
—
Read/Write PORTE Data Latch
51, 132
LATD(5)
LATC
Read/Write PORTD Data Latch
Read/Write PORTC Data Latch
Read/Write PORTB Data Latch
xxxx xxxx
xxxx xxxx
xxxx xxxx
51, 128
51, 123
51, 117
LATB
LATA
LATA<7>(2) LATA<6>(1) Read/Write PORTA Data Latch
Timer5 Timer register High Byte
xxxx xxxx
xxxx xxxx
xxxx xxxx
---- xxxx
51, 111
146
TMR5H
TMR5L
PORTE
Timer5 Timer register Low Byte
146
—
—
—
—
RE3(6)
Read PORTE pins,
51, 132
Write PORTE Data Latch(5)
PORTD
PORTC
Read PORTD pins, Write PORTD Data Latch
Read PORTC pins, Write PORTC Data Latch
xxxx xxxx
xxxx xxxx
51, 128
51, 123
PORTB
PORTA
Read PORTB pins, Write PORTB Data Latch(4)
xxxx xxxx
xx0x 0000
51, 117
51, 111
52, 186
52, 186
184
RA7(2)
RA6(1)
Read PORTA pins, Write PORTA Data Latch
PTCON0
PTCON1
PTOPS3
PTEN
PTOPS2
PTDIR
PTOPS1
—
PTOPS0
—
PTCKPS1 PTCKPS0
PTMOD1
—
PTMOD0
—
0000 0000
00-- ----
—
—
PTMRL
PTMRH
PWM Time Base register (lower 8 bits).
0000 0000
---- 0000
UNUSED
PWM Time Base register (Upper 4 bits)
184
Legend:
Note 1:
x= unknown, u= unchanged, – = unimplemented, q= value depends on condition
RA6 and associated bits are configured as port pins in RCIO, ECIO and INTIO2 (with port function on RA6) Oscillator mode only, and read
‘0’ in all other oscillator modes.
2:
3:
4:
RA7 and associated bits are configured as port pins in INTIO2 Oscillator mode only and read ‘0’ in all other modes.
Bit 21 of the PC is only available in Test mode and serial programming modes.
If PBADEN = 0, PORTB<4:0> are configured as digital input and read unknown, and if PBADEN = 1, PORTB<4:0> are configured as
analog input and read ‘0’ following a Reset.
5:
6:
These registers and/or bits are not implemented on the PIC18F2X31 devices, and read as ‘0’.
The RE3 port bit is only available when MCLRE fuse (CONFIG3H<7>) is programmed to ‘0’. Otherwise, RE3 reads ‘0’. This bit is read-only.
DS39616B-page 68
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 5-2:
REGISTER FILE SUMMARY (PIC18F2331/2431/4331/4431) (CONTINUED)
Value on
POR, BOR
Details on
page:
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PTPERL
PTPERH
PDC0L
PDC0H
PDC1L
PDC1H
PDC2L
PDC2H
PDC3L
PDC3H
PWM Time Base Period register (Lower 8 bits).
UNUSED
1111 1111
---- 1111
--00 0000
0000 0000
0000 0000
--00 0000
0000 0000
--00 0000
0000 0000
--00 0000
0000 0000
---- 0000
-101 0000
0000 0-00
0000 0000
-000 0000
1111 1111
0000 0000
184
184
PWM Time Base Period register (Upper 4 bits)
PWM Duty Cycle #0L register (Lower 8 bits)
UNUSED
184
PWM Duty Cycle #0H register (Upper 6 bits)
184
PWM Duty Cycle #1L register (Lower 8 bits)
UNUSED
184
PWM Duty Cycle #1H register (Upper 6 bits)
PWM Duty Cycle #2H register (Upper 6 bits)
PWM Duty Cycle #3H register (Upper 6 bits)
184
PWM Duty Cycle #2L register (Lower 8 bits)
UNUSED
184
184
PWM Duty Cycle #3L register (Lower 8 bits)
UNUSED
184
184
SEVTCMPL PWM Special Event Compare register (Lower 8 bits)
N/A
SEVTCMPH
PWMCON0
PWMCON1
DTCON
UNUSED
PWMEN2 PWMEN1
SEVOPS3 SEVOPS2 SEVOPS1 SEVOPS0
PWM Special Event Compare reg (Upper 4 bits)
N/A
—
PWMEN0
PMOD3
SEVTDIR
DT3
PMOD2
—
PMOD1
UDIS
PMOD0
OSYNC
DT0
52, 187
52, 188
52, 200
52, 208
52, 203
52, 204
52,
DTPS1
—
DTPS0
FLTBS
POVD6
POUT6
DT5
DT4
DT2
DT1
FLTCONFIG
OVDCOND
OVDCONS
FLTBMOD
POVD5
POUT5
FLTBEN
POVD4
POUT4
FLTCON
POVD3
POUT3
FLTAS
POVD2
POUT2
FLTAMOD
POVD1
POUT1
FLTAEN
POVD0
POUT0
POVD7
POUT7
CAP1BUFH/ Capture 1 register, High Byte/
VELRH Velocity register, High Byte
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
CAP1BUFL/ Capture 1 register Low Byte/
VELRL Velocity register, Low Byte
52
52
52
53
53
CAP2BUFH/ Capture 2 register, High Byte/
POSCNTH
QEI Position Counter register, High Byte
CAP2BUFL/ Capture 2 Reg., Low Byte/
POSCNTL
QEI Position Counter register, Low Byte
CAP3BUFH/ Capture 3 Reg., High Byte/
MAXCNTH
QEI Max. Count Limit register, High Byte
CAP3BUFL/ Capture 3 Reg., Low Byte/
MAXCNTL
QEI Max. Count Limit register, Low Byte
CAP1CON
—
—
—
—
CAP1REN
CAP2REN
CAP3REN
FLT4EN
—
—
—
—
CAP1M3
CAP2M3
CAP3M3
FLT1EN
CAP1M2
CAP2M2
CAP3M2
FLTCK2
CAP1M1
CAP2M1
CAP3M1
FLTCK1
CAP1M0 -0-0 0000
CAP2M0 -0-0 0000
CAP3M0 -0-0 0000
FLTCK0 -000 0000
53, 163
53, 163
53, 163
53, 178
CAP2CON
CAP3CON
DFLTCON
—
—
FLT3EN
FLT2EN
Legend:
Note 1:
x= unknown, u= unchanged, – = unimplemented, q= value depends on condition
RA6 and associated bits are configured as port pins in RCIO, ECIO and INTIO2 (with port function on RA6) Oscillator mode only, and read
‘0’ in all other oscillator modes.
2:
3:
4:
RA7 and associated bits are configured as port pins in INTIO2 Oscillator mode only and read ‘0’ in all other modes.
Bit 21 of the PC is only available in Test mode and serial programming modes.
If PBADEN = 0, PORTB<4:0> are configured as digital input and read unknown, and if PBADEN = 1, PORTB<4:0> are configured as
analog input and read ‘0’ following a Reset.
5:
6:
These registers and/or bits are not implemented on the PIC18F2X31 devices, and read as ‘0’.
The RE3 port bit is only available when MCLRE fuse (CONFIG3H<7>) is programmed to ‘0’. Otherwise, RE3 reads ‘0’. This bit is read-only.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 69
PIC18F2331/2431/4331/4431
5.10
Access Bank
5.11 Bank Select Register (BSR)
The Access Bank is an architectural enhancement
which is very useful for C compiler code optimization.
The techniques used by the C compiler may also be
useful for programs written in assembly.
The need for a large general purpose memory space
dictates a RAM banking scheme. The data memory is
partitioned into as many as sixteen banks. When using
direct addressing, the BSR should be configured for the
desired bank.
This data memory region can be used for:
BSR<3:0> holds the upper 4 bits of the 12-bit RAM
address. The BSR<7:4> bits will always read ‘0’s, and
writes will have no effect (see Figure 5-7).
• Intermediate computational values
• Local variables of subroutines
• Faster context saving/switching of variables
• Common variables
A
MOVLB instruction has been provided in the
instruction set to assist in selecting banks.
• Faster evaluation/control of SFRs (no banking)
If the currently selected bank is not implemented, any
read will return all ‘0’s and all writes are ignored. The
Status register bits will be set/cleared as appropriate for
the instruction performed.
The Access Bank is comprised of the last 128 bytes in
Bank 15 (SFRs) and the first 128 bytes in Bank 0.
These two sections will be referred to as Access RAM
High and Access RAM Low, respectively. Figure 5-6
indicates the Access RAM areas.
Each Bank extends up to FFh (256 bytes). All data
memory is implemented as static RAM.
A bit in the instruction word specifies if the operation is
to occur in the bank specified by the BSR register or in
the Access Bank. This bit is denoted as the ‘a’ bit (for
access bit).
A MOVFFinstruction ignores the BSR, since the 12-bit
addresses are embedded into the instruction word.
Section 5.12 “Indirect Addressing, INDF and FSR
Registers” provides a description of indirect address-
ing, which allows linear addressing of the entire RAM
space.
When forced in the Access Bank (a = 0), the last
address in Access RAM Low is followed by the first
address in Access RAM High. Access RAM High maps
the Special Function Registers, so these registers can
be accessed without any software overhead. This is
useful for testing status flags and modifying control bits.
FIGURE 5-7:
DIRECT ADDRESSING
Direct Addressing
(3)
From Opcode
BSR<7:4>
BSR<3:0>
7
0
0
0
0
0
(2)
(3)
Bank Select
Location Select
00h
01h
100h
0Eh
E00h
0Fh
F00h
000h
Data
Memory(1)
0FFh
1FFh
EFFh
FFFh
Bank 0
Bank 1
Bank 14 Bank 15
Note 1: For register file map detail, see Table 5-1.
2: The access bit of the instruction can be used to force an override of the selected bank (BSR<3:0>) to the
registers of the Access Bank.
3: The MOVFFinstruction embeds the entire 12-bit address in the instruction.
DS39616B-page 70
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
If INDF0, INDF1 or INDF2 are read indirectly via a FSR,
5.12 Indirect Addressing, INDF and
all ‘0’s are read (zero bit is set). Similarly, if INDF0,
INDF1 or INDF2 are written to indirectly, the operation
will be equivalent to a NOP instruction and the Status
bits are not affected.
FSR Registers
Indirect addressing is a mode of addressing data mem-
ory, where the data memory address in the instruction
is not fixed. An FSR register is used as a pointer to the
data memory location that is to be read or written. Since
this pointer is in RAM, the contents can be modified by
the program. This can be useful for data tables in the
data memory and for software stacks. Figure 5-8
shows how the fetched instruction is modified prior to
being executed.
5.12.1
INDIRECT ADDRESSING
OPERATION
Each FSR register has an INDF register associated
with it, plus four additional register addresses. Perform-
ing an operation using one of these five registers deter-
mines how the FSR will be modified during indirect
addressing.
Indirect addressing is possible by using one of the
INDF registers. Any instruction using the INDF register
actually accesses the register pointed to by the File
Select Register, FSR. Reading the INDF register itself,
indirectly (FSR = 0), will read 00h. Writing to the INDF
register indirectly, results in a no operation. The FSR
register contains a 12-bit address, which is shown in
Figure 5-9.
When data access is performed using one of the five
INDFn locations, the address selected will configure
the FSRn register to:
• Do nothing to FSRn after an indirect access (no
change) – INDFn
• Auto-decrement FSRn after an indirect access
(post-decrement) – POSTDECn
The INDFn register is not a physical register. Address-
ing INDFn actually addresses the register whose
address is contained in the FSRn register (FSRn is a
pointer). This is indirect addressing.
• Auto-increment FSRn after an indirect access
(post-increment) – POSTINCn
• Auto-increment FSRn before an indirect access
(pre-increment) – PREINCn
Example 5-5 shows a simple use of indirect addressing
to clear the RAM in Bank 1 (locations 100h-1FFh) in a
minimum number of instructions.
• Use the value in the WREG register as an offset
to FSRn. Do not modify the value of the WREG or
the FSRn register after an indirect access (no
change) – PLUSWn
EXAMPLE 5-5:
HOW TO CLEAR RAM
(BANK 1) USING
When using the auto-increment or auto-decrement fea-
tures, the effect on the FSR is not reflected in the Status
register. For example, if the indirect address causes the
FSR to equal ‘0’, the Z bit will not be set.
INDIRECT ADDRESSING
LFSR
FSR0, 0x100;
NEXT
CLRF
POSTINC0
; Clear INDF
; register then
; inc pointer
; All done with
; Bank1?
; NO, clear next
; YES, continue
Auto-incrementing or auto-decrementing a FSR affects
all 12 bits. That is, when FSRnL overflows from an
increment, FSRnH will be incremented automatically.
BTFSS
GOTO
FSR0H, 1
NEXT
Adding these features allows the FSRn to be used as a
stack pointer, in addition to its uses for table operations
in data memory.
CONTINUE
There are three indirect addressing registers. To
address the entire data memory space (4096 bytes),
these registers are 12-bits wide. To store the 12 bits of
addressing information, two 8-bit registers are
required:
Each FSR has an address associated with it that per-
forms an indexed indirect access. When a data access
to this INDFn location (PLUSWn) occurs, the FSRn is
configured to add the signed value in the WREG regis-
ter and the value in FSR to form the address before an
indirect access. The FSR value is not changed. The
WREG offset range is -128 to +127.
1. FSR0: composed of FSR0H:FSR0L
2. FSR1: composed of FSR1H:FSR1L
3. FSR2: composed of FSR2H:FSR2L
If an FSR register contains a value that points to one of
the INDFn, an indirect read will read 00h (zero bit is
set), while an indirect write will be equivalent to a NOP
(Status bits are not affected).
In addition, there are registers INDF0, INDF1 and
INDF2, which are not physically implemented. Reading
or writing to these registers activates indirect address-
ing, with the value in the corresponding FSR register
being the address of the data. If an instruction writes a
value to INDF0, the value will be written to the address
pointed to by FSR0H:FSR0L. A read from INDF1 reads
the data from the address pointed to by
FSR1H:FSR1L. INDFn can be used in code anywhere
an operand can be used.
If an indirect addressing write is performed when the
target address is an FSRnH or FSRnL register, the data
is written to the FSR register, but no pre- or post-
increment/decrement is performed.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 71
PIC18F2331/2431/4331/4431
FIGURE 5-8:
INDIRECT ADDRESSING OPERATION
0h
RAM
Instruction
Executed
Opcode
Address
12
FFFh
File Address = access of an indirect addressing register
BSR<3:0>
12
12
Instruction
Fetched
4
8
Opcode
File
FSR
FIGURE 5-9:
INDIRECT ADDRESSING
Indirect Addressing
FSRnH:FSRnL
3
0
7
0
0
11
Location Select
0000h
Data
Memory(1)
0FFFh
Note 1: For register file map detail, see Table 5-1.
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For example, CLRF STATUSwill clear the upper three
bits and set the Z bit. This leaves the Status register as
5.13 Status Register
The Status register, shown in Register 5-2, contains the
arithmetic status of the ALU. The Status register can be
the operand for any instruction, as with any other reg-
ister. If the Status register is the destination for an
instruction that affects the Z, DC, C, OV or N bits, then
the write to these five bits is disabled. These bits are set
or cleared according to the device logic. Therefore, the
result of an instruction with the Status register as desti-
nation may be different than intended.
000u u1uu(where u= unchanged).
It is recommended, therefore, that only BCF, BSF,
SWAPF, MOVFF and MOVWF instructions are used to
alter the Status register, because these instructions do
not affect the Z, C, DC, OV or N bits in the Status reg-
ister. For other instructions not affecting any status bits,
see Table 23-2.
Note:
The C and DC bits operate as a borrow
and digit borrow bit respectively, in sub-
traction.
REGISTER 5-2:
STATUS REGISTER
U-0
—
U-0
—
U-0
—
R/W-x
R/W-x
OV
R/W-x
Z
R/W-x
DC
R/W-x
C
N
bit 7
bit 0
bit 7-5
bit 4
Unimplemented: Read as ‘0’
N: Negative bit
This bit is used for signed arithmetic (2’s complement). It indicates whether the result was
negative (ALU MSB = 1).
1= Result was negative
0= Result was positive
bit 3
OV: Overflow bit
This bit is used for signed arithmetic (2’s complement). It indicates an overflow of the
7-bit magnitude, which causes the sign bit (bit7) to change state.
1= Overflow occurred for signed arithmetic (in this arithmetic operation)
0= No overflow occurred
bit 2
bit 1
Z: Zero bit
1= The result of an arithmetic or logic operation is zero
0= The result of an arithmetic or logic operation is not zero
DC: Digit carry/borrow bit
For ADDWF, ADDLW, SUBLWand SUBWFinstructions
1= A carry-out from the 4th low order bit of the result occurred
0= No carry-out from the 4th low order bit of the result
Note:
For borrow, the polarity is reversed. A subtraction is executed by adding the
2’s complement of the second operand. For rotate (RRF, RLF) instructions, this
bit is loaded with either the bit 4 or bit 3 of the source register.
bit 0
C: Carry/borrow bit
For ADDWF, ADDLW, SUBLWand SUBWFinstructions
1= A carry-out from the Most Significant bit of the result occurred
0= No carry-out from the Most Significant bit of the result occurred
Note:
For borrow, the polarity is reversed. A subtraction is executed by adding the
2’s complement of the second operand. For rotate (RRF, RLF) instructions, this
bit is loaded with either the high- or low-order bit of the source register.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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5.14 RCON Register
Note 1: If the BOREN configuration bit is set
(Brown-out Reset enabled), the BOR bit
is ‘1’ on a Power-on Reset. After a Brown-
out Reset has occurred, the BOR bit will
be cleared and must be set by firmware to
indicate the occurrence of the next
Brown-out Reset.
The Reset Control (RCON) register contains flag bits
that allow differentiation between the sources of a
device Reset. These flags include the TO, PD, POR,
BOR and RI bits. This register is readable and writable.
2: It is recommended that the POR bit be set
after
a Power-on Reset has been
detected, so that subsequent Power-on
Resets may be detected.
REGISTER 5-3:
RCON REGISTER
R/W-0
IPEN
U-0
—
U-0
—
R/W-1
RI
R-1
TO
R-1
PD
R/W-0
POR
R/W-0
BOR
bit 7
bit 0
bit 7
IPEN: Interrupt Priority Enable bit
1= Enable priority levels on interrupts
0= Disable priority levels on interrupts (PIC16CXXX Compatibility mode)
bit 6-5 Unimplemented: Read as ‘0’
bit 4
RI: RESETInstruction Flag bit
1= The RESETinstruction was not executed (set by firmware only)
0= The RESETinstruction was executed causing a device Reset
(must be set in firmware after a Brown-out Reset occurs)
bit 3
bit 2
bit 1
TO: Watchdog Time-out Flag bit
1= Set by power-up, CLRWDTinstruction, or SLEEPinstruction
0= A WDT time-out occurred
PD: Power-down Detection Flag bit
1= Set by power-up or by the CLRWDTinstruction
0= Cleared by execution of the SLEEPinstruction
POR: Power-on Reset Status bit
1= A Power-on Reset has not occurred (set by firmware only)
0= A Power-on Reset occurred
(must be set in firmware after a Power-on Reset occurs)
bit 0
BOR: Brown-out Reset Status bit
1= A Brown-out Reset has not occurred (set by firmware only)
0= A Brown-out Reset occurred
(must be set in firmware after a Brown-out Reset occurs)
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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The program memory space is 16-bits wide, while the
6.0
FLASH PROGRAM MEMORY
data RAM space is 8-bits wide. Table reads and table
writes move data between these two memory spaces
through an 8-bit register (TABLAT).
The Flash program memory is readable, writable and
erasable during normal operation over the entire VDD
range.
Table read operations retrieve data from program
memory and place it into TABLAT in the data RAM
space. Figure 6-1 shows the operation of a table read
with program memory and data RAM.
A read from program memory is executed on one byte
at a time. A write to program memory is executed on
blocks of 8 bytes at a time. Program memory is erased
in blocks of 64 bytes at a time. A bulk erase operation
may not be issued from user code.
Table write operations store data from TABLAT in the
data memory space into holding registers in program
memory. The procedure to write the contents of the
holding registers into program memory is detailed in
Section 6.5 “Writing to Flash Program Memory”.
Figure 6-2 shows the operation of a table write with
program memory and data RAM.
While writing or erasing program memory, instruction
fetches cease until the operation is complete. The
program memory cannot be accessed during the write
or erase, therefore, code cannot execute. An internal
programming timer terminates program memory writes
and erases.
Table operations work with byte entities. A table block
containing data, rather than program instructions, is not
required to be word aligned. Therefore, a table block
can start and end at any byte address. If a table write is
being used to write executable code into program
memory, program instructions will need to be word
aligned, (TBLPTRL<0> = 0).
A value written to program memory does not need to be
a valid instruction. Executing a program memory
location that forms an invalid instruction results in a
NOP.
6.1
Table Reads and Table Writes
The EEPROM on-chip timer controls the write and
erase times. The write and erase voltages are gener-
ated by an on-chip charge pump rated to operate over
the voltage range of the device for byte or word
operations.
In order to read and write program memory, there are
two operations that allow the processor to move bytes
between the program memory space and the data
RAM:
• Table Read (TBLRD)
• Table Write (TBLWT)
FIGURE 6-1:
TABLE READ OPERATION
Instruction: TBLRD*
(1)
Program Memory
Table Pointer
Table Latch (8-bit)
TABLAT
TBLPTRU TBLPTRH TBLPTRL
Program Memory
(TBLPTR)
Note 1: Table Pointer points to a byte in program memory.
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FIGURE 6-2:
TABLE WRITE OPERATION
Instruction: TBLWT*
Program Memory
Holding Registers
(1)
Table Pointer
Table Latch (8-bit)
TABLAT
TBLPTRU TBLPTRH TBLPTRL
Program Memory
(TBLPTR)
Note 1: Table Pointer actually points to one of eight holding registers, the address of which is determined by
TBLPTRL<2:0>. The process for physically writing data to the Program Memory Array is discussed in
Section 6.5 “Writing to Flash Program Memory”.
The WREN bit enables and disables erase and write
operations. When set, erase and write operations are
allowed. When clear, erase and write operations are
disabled – the WR bit cannot be set while the WREN bit
is clear. This process helps to prevent accidental writes
to memory due to errant (unexpected) code execution.
6.2
Control Registers
Several control registers are used in conjunction with
the TBLRDand TBLWTinstructions. These include the:
• EECON1 register
• EECON2 register
• TABLAT register
• TBLPTR registers
Firmware should keep the WREN bit clear at all times,
except when starting erase or write operations. Once
firmware has set the WR bit, the WREN bit may be
cleared. Clearing the WREN bit will not affect the
operation in progress.
6.2.1
EECON1 AND EECON2 REGISTERS
EECON1 is the control register for memory accesses.
The WRERR bit is set when a write operation is inter-
rupted by a Reset. In these situations, the user can
check the WRERR bit and rewrite the location. It will be
necessary to reload the data and address registers
(EEDATA and EEADR) as these registers have cleared
as a result of the Reset.
EECON2 is not a physical register. Reading EECON2
will read all ‘0’s. The EECON2 register is used
exclusively in the memory write and erase sequences.
Control bit EEPGD determines if the access will be to
program or data EEPROM memory. When clear, oper-
ations will access the data EEPROM memory. When
set, program memory is accessed.
Control bits RD and WR start read and erase/write
operations, respectively. These bits are set by firm-
ware, and cleared by hardware at the completion of the
operation.
Control bit CFGS determines if the access will be to the
configuration registers or to program memory/data
EEPROM memory. When set, subsequent operations
access configuration registers. When CFGS is clear,
the EEPGD bit selects either program Flash or data
EEPROM memory.
The RD bit cannot be set when accessing program
memory (EEPGD = 1). Program memory is read using
table read instructions. See Section 6.3 “Reading the
Flash Program Memory” regarding table reads.
The FREE bit controls program memory erase opera-
tions. When the FREE bit is set, the erase operation is
initiated on the next WR command. When FREE is
clear, only writes are enabled.
Note:
Interrupt flag bit EEIF, in the PIR2 register,
is set when the write is complete. It must
be cleared in software.
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REGISTER 6-1:
EECON1 REGISTER
R/W-x
R/W-x
CFGS
U-0
—
R/W-0
FREE
R/W-x
R/W-0
WREN
R/S-0
WR
R/S-0
RD
EEPGD
WRERR
bit 7
bit 0
bit 7
bit 6
EEPGD: Flash Program or Data EEPROM Memory Select bit
1= Access program Flash memory
0= Access data EEPROM memory
CFGS: Flash Program/Data EE or Configuration Select bit
1= Access configuration registers
0= Access program Flash or data EEPROM memory
bit 5
bit 4
Unimplemented: Read as ‘0’
FREE: Flash Row Erase Enable bit
1= Erase the program memory row addressed by TBLPTR on the next WR command
(cleared by completion of erase operation – TBLPTR<5:0> are ignored)
0= Perform write only
bit 3
WRERR: EEPROM Error Flag bit
1= A write operation was prematurely terminated (any Reset during self-timed
programming)
0= The write operation completed normally
Note:
When a WRERR occurs, the EEPGD and CFGS bits are not cleared. This allows
tracing of the error condition.
bit 2
bit 1
WREN: Write Enable bit
1= Allows erase or write cycles
0= Inhibits erase or write cycles
WR: Write Control bit
1= Initiates a data EEPROM erase/write cycle or a program memory erase cycle or write
cycle.
(The operation is self-timed and the bit is cleared by hardware once write is complete. The
WR bit can only be set (not cleared) in software.)
0= Write cycle completed
bit 0
RD: Read Control bit
1= Initiates a memory read
(Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared)
in software. RD bit cannot be set when EEPGD = 1.)
0= Read completed
Legend:
R = Readable bit
W = Writable bit
x = Bit is unknown
S = Settable only
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set ‘0’ = Bit is cleared
- n = Value at POR
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6.2.2
TABLAT – TABLE LATCH REGISTER
6.2.4
TABLE POINTER BOUNDARIES
The Table Latch (TABLAT) is an 8-bit register mapped
into the SFR space. The Table Latch is used to hold
8-bit data during data transfers between program
memory and data RAM.
TBLPTR is used in reads, writes and erases of the
Flash program memory.
When a TBLRD is executed, all 22 bits of the Table
Pointer determine which byte is read from program or
configuration memory into TABLAT.
6.2.3
TBLPTR – TABLE POINTER
REGISTER
When a TBLWTis executed, the three LSbs of the Table
Pointer (TBLPTR<2:0>) determine which of the eight
program memory holding registers is written to. When
the timed write to program memory (long write) begins,
the 19 MSbs of the Table Pointer, TBLPTR
(TBLPTR<21:3>), will determine which program
memory block of 8 bytes is written to (TBLPTR<2:0>
are ignored). For more detail, see Section 6.5
“Writing to Flash Program Memory”.
The Table Pointer (TBLPTR) addresses a byte within
the program memory. The TBLPTR is comprised of
three SFR registers: Table Pointer Upper Byte, Table
Pointer High Byte and Table Pointer Low Byte
(TBLPTRU:TBLPTRH:TBLPTRL). These three regis-
ters join to form a 22-bit wide pointer. The low order 21
bits allow the device to address up to 2 Mbytes of pro-
gram memory space. Setting the 22nd bit allows
access to the Device ID, the User ID and the
Configuration bits.
When an erase of program memory is executed, the 16
MSbs of the Table Pointer (TBLPTR<21:6>) point to the
64-byte block that will be erased. The Least Significant
bits (TBLPTR<5:0>) are ignored.
The TBLPTR is used by the TBLRDand TBLWTinstruc-
tions. These instructions can update the TBLPTR in
one of four ways based on the table operation. These
operations are shown in Table 6-1. These operations
on the TBLPTR only affect the low order 21 bits.
Figure 6-3 describes the relevant boundaries of
TBLPTR based on Flash program memory operations.
TABLE 6-1:
Example
TABLE POINTER OPERATIONS WITH TBLRD AND TBLWT INSTRUCTIONS
Operation on Table Pointer
TBLRD*
TBLWT*
TBLPTR is not modified
TBLRD*+
TBLWT*+
TBLPTR is incremented after the read/write
TBLPTR is decremented after the read/write
TBLPTR is incremented before the read/write
TBLRD*-
TBLWT*-
TBLRD+*
TBLWT+*
FIGURE 6-3:
TABLE POINTER BOUNDARIES BASED ON OPERATION
21
16 15
TBLPTRH
8
7
TBLPTRL
0
TBLPTRU
ERASE – TBLPTR<21:6>
LONG WRITE – TBLPTR<21:3>
READ or WRITE – TBLPTR<21:0>
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The internal program memory is typically organized by
words. The Least Significant bit of the address selects
between the high and low bytes of the word. Figure 6-4
6.3
Reading the Flash Program
Memory
The TBLRD instruction is used to retrieve data from
program memory and placed into data RAM. Table
reads from program memory are performed one byte at
a time.
shows the interface between the internal program
memory and the TABLAT.
TBLPTR points to a byte address in program space.
Executing a TBLRDinstruction places the byte pointed
to into TABLAT. In addition, TBLPTR can be modified
automatically for the next table read operation.
FIGURE 6-4:
READS FROM FLASH PROGRAM MEMORY
Program Memory
Odd (High) Byte
Even (Low) Byte
TBLPTR
LSB = 0
TBLPTR
LSB = 1
Instruction Register
(IR)
TABLAT
Read Register
EXAMPLE 6-1:
READING A FLASH PROGRAM MEMORY WORD
MOVLW CODE_ADDR_UPPER
MOVWF TBLPTRU
; Load TBLPTR with the base
; address of the word
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
READ_WORD
TBLRD*+
; read into TABLAT and increment TBLPTR
; get data
MOVFW TABLAT
MOVWF WORD_EVEN
TBLRD*+
MOVFW TABLAT
MOVWF WORD_ODD
; read into TABLAT and increment TBLPTR
; get data
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6.4.1
FLASH PROGRAM MEMORY
ERASE SEQUENCE
6.4
Erasing Flash Program Memory
The minimum erase block size is 32 words or 64 bytes
under firmware control. Only through the use of an
external programmer, or through ICSP control can
larger blocks of program memory be bulk erased. Word
erase in Flash memory is not supported.
The sequence of events for erasing a block of internal
program memory location is:
1. Load table pointer with address of row being
erased.
When initiating an erase sequence from the micro-
controller itself, a block of 64 bytes of program memory
is erased. The Most Significant 16 bits of the
TBLPTR<21:6> point to the block being erased.
TBLPTR<5:0> are ignored.
2. Set the EECON1 register for the erase
operation:
- set EEPGD bit to point to program
memory;
- clear the CFGS bit to access program
memory;
The EECON1 register commands the erase operation.
The EEPGD bit must be set to point to the Flash pro-
gram memory. The CFGS bit must be clear to access
program Flash and data EEPROM memory. The
WREN bit must be set to enable write operations. The
FREE bit is set to select an erase operation. The WR
bit is set as part of the required instruction sequence
(as shown in Example 6-2), and starts the actual erase
operation. It is not necessary to load the TABLAT
register with any data, as it is ignored.
- set WREN bit to enable writes;
- set FREE bit to enable the erase.
3. Disable interrupts.
4. Write 55h to EECON2.
5. Write AAh to EECON2.
6. Set the WR bit. This will begin the row erase
cycle.
7. The CPU will stall for duration of the erase
(about 2 ms using internal timer).
For protection, the write initiate sequence using
EECON2 must be used.
8. Execute a NOP.
9. Re-enable interrupts.
A long write is necessary for erasing the internal Flash.
Instruction execution is halted while in a long write
cycle. The long write will be terminated by the internal
programming timer.
EXAMPLE 6-2:
ERASING A FLASH PROGRAM MEMORY ROW
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
CODE_ADDR_UPPER
TBLPTRU
CODE_ADDR_HIGH
TBLPTRH
CODE_ADDR_LOW
TBLPTRL
; load TBLPTR with the base
; address of the memory block
ERASE_ROW
BSF
BSF
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
EECON1,EEPGD
EECON1,WREN
EECON1,FREE
INTCON,GIE
55h
EECON2
AAh
EECON2
EECON2,WR
; point to Flash program memory
; enable write to memory
; enable Row Erase operation
; disable interrupts
; write 55H
Required
Sequence
; write AAH
; start erase (CPU stall)
NOP
BSF
INTCON,GIE
; re-enable interrupts
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Since the Table Latch (TABLAT) is only a single byte,
6.5
Writing to Flash Program Memory
the TBLWT instruction has to be executed 8 times for
each programming operation. All of the table write
operations will essentially be short writes, because only
the holding registers are written. At the end of updating
8 registers, the EECON1 register must be written to, to
start the programming operation with a long write.
The programming block size is 4 words or 8 bytes.
Word or byte programming is not supported.
Table writes are used internally to load the holding
registers needed to program the Flash memory. There
are 8 holding registers used by the table writes for
programming.
The long write is necessary for programming the
internal Flash. Instruction execution is halted while in a
long write cycle. The long write will be terminated by
the internal programming timer.
FIGURE 6-5:
TABLE WRITES TO FLASH PROGRAM MEMORY
TABLAT
Write Register
8
8
8
8
TBLPTR = xxxxx0
TBLPTR = xxxxx2
TBLPTR = xxxxx7
Holding Register
TBLPTR = xxxxx1
Holding Register
Holding Register
Holding Register
Program Memory
10. Write AAh to EECON2.
6.5.1
FLASH PROGRAM MEMORY WRITE
SEQUENCE
11. Set the WR bit. This will begin the write cycle.
12. The CPU will stall for duration of the write (about
2 ms using internal timer).
The sequence of events for programming an internal
program memory location should be:
13. Execute a NOP.
1. Read 64 bytes into RAM.
14. Re-enable interrupts.
2. Update data values in RAM as necessary.
3. Load Table Pointer with address being erased.
15. Repeat steps 6-14 seven times, to write 64
bytes.
4. Do the row erase procedure (see Section 6.4.1
“Flash Program Memory Erase Sequence”).
16. Verify the memory (table read).
This procedure will require about 18 ms to update one
row of 64 bytes of memory. An example of the required
code is given in Example 6-3.
5. Load Table Pointer with address of first byte
being written.
6. Write the first 8 bytes into the holding registers
with auto-increment.
7. Set the EECON1 register for the write operation:
- set EEPGD bit to point to program
memory;
- clear the CFGS bit to access program
memory;
- set WREN bit to enable byte writes.
8. Disable interrupts.
9. Write 55h to EECON2.
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EXAMPLE 6-3:
WRITING TO FLASH PROGRAM MEMORY
MOVLW
D'64
; number of bytes in erase block
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
COUNTER
BUFFER_ADDR_HIGH
FSR0H
BUFFER_ADDR_LOW
FSR0L
CODE_ADDR_UPPER
TBLPTRU
CODE_ADDR_HIGH
TBLPTRH
CODE_ADDR_LOW
TBLPTRL
; point to buffer
; Load TBLPTR with the base
; address of the memory block
; 6 LSB = 0
READ_BLOCK
TBLRD*+
MOVFW
; read into TABLAT, and inc
; get data
TABLAT
MOVWF
DECFSZ COUNTER
POSTINC0
; store data and increment FSR0
; done?
GOTO
READ_BLOCK
; repeat
MODIFY_WORD
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
DATA_ADDR_HIGH
FSR0H
DATA_ADDR_LOW
FSR0L
NEW_DATA_LOW
POSTINC0
NEW_DATA_HIGH
INDF0
; point to buffer
; update buffer word and increment FSR0
; update buffer word
ERASE_BLOCK
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
BCF
BSF
BSF
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
CODE_ADDR_UPPER
TBLPTRU
CODE_ADDR_HIGH
TBLPTRH
CODE_ADDR_LOW
TBLPTRL
EECON1,CFGS
EECON1,EEPGD
EECON1,WREN
EECON1,FREE
INTCON,GIE
55h
; load TBLPTR with the base
; address of the memory block
; 6 LSB = 0
; point to PROG/EEPROM memory
; point to Flash program memory
; enable write to memory
; enable Row Erase operation
; disable interrupts
; Required sequence
; write 55H
EECON2
AAh
EECON2
EECON1,WR
; write AAH
; start erase (CPU stall)
NOP
BSF
INTCON,GIE
; re-enable interrupts
WRITE_BUFFER_BACK
MOVLW
8
; number of write buffer groups of 8 bytes
; point to buffer
MOVWF
MOVLW
MOVWF
COUNTER_HI
BUFFER_ADDR_HIGH
FSR0H
MOVLW
MOVWF
BUFFER_ADDR_LOW
FSR0L
PROGRAM_LOOP
MOVLW
8
; number of bytes in holding register
MOVWF
COUNTER
WRITE_WORD_TO_HREGS
MOVFW
POSTINC0
TABLAT
; get low byte of buffer data and increment FSR0
; present data to table latch
; short write
MOVWF
TBLWT+*
; to internal TBLWT holding register, increment
; TBLPTR
DECFSZ COUNTER
; loop until buffers are full
GOTO
WRITE_WORD_TO_HREGS
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EXAMPLE 6-3:
WRITING TO FLASH PROGRAM MEMORY (CONTINUED)
PROGRAM_MEMORY
BCF
INTCON,GIE
55h
EECON2
AAh
EECON2
EECON1,WR
; disable interrupts
; required sequence
; write 55H
MOVLW
MOVWF
MOVLW
MOVWF
BSF
; write AAH
; start program (CPU stall)
NOP
BSF
INTCON, GIE
; re-enable interrupts
; loop until done
DECFSZ COUNTER_HI
GOTO PROGRAM_LOOP
BCF
EECON1, WREN
; disable write to memory
6.5.2
WRITE VERIFY
6.6
Flash Program Operation During
Code Protection
Depending on the application, good programming
practice may dictate that the value written to the
memory should be verified against the original value.
This should be used in applications where excessive
writes can stress bits near the specification limit.
See Section 22.5 “Program Verification and Code
Protection” for details on code protection of Flash pro-
gram memory.
6.5.3
UNEXPECTED TERMINATION OF
WRITE OPERATION
If a write is terminated by an unplanned event, such as
loss of power or an unexpected Reset, the memory
location just programmed should be verified and repro-
grammed if needed. The WRERR bit is set when a
write operation is interrupted by a MCLR Reset, or a
WDT Time-out Reset during normal operation. In these
situations, users can check the WRERR bit and rewrite
the location.
TABLE 6-2:
Name
REGISTERS ASSOCIATED WITH PROGRAM FLASH MEMORY
Value on
Value on:
POR, BOR
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
all other
Resets
TBLPTRU
—
—
bit21 Program Memory Table Pointer Upper Byte
(TBLPTR<20:16>)
--00 0000 --00 0000
TBPLTRH Program Memory Table Pointer High Byte (TBLPTR<15:8>)
TBLPTRL Program Memory Table Pointer High Byte (TBLPTR<7:0>)
0000 0000 0000 0000
0000 0000 0000 0000
0000 0000 0000 0000
0000 000x 0000 000u
TABLAT
INTCON
EECON2
EECON1
IPR2
Program Memory Table Latch
GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE
TMR0IF
INTF
RBIF
RD
EEPROM Control Register2 (not a physical register)
—
—
EEPGD
OSFIP
OSFIF
OSFIE
CFGS
—
—
—
—
—
FREE
EEIP
EEIF
EEIE
WRERR WREN
WR
—
xx-0 x000 uu-0 u000
—
—
—
LVDIP
LVDIF
LVDIE
CCP2IP 1--1 -1-1 1--1 -1-1
CCP2IF 0--0 -0-0 0--0 -0-0
CCP2IE 0--0 -0-0 0--0 -0-0
PIR2
—
—
PIE2
—
—
Legend:
x= unknown, u= unchanged, r = reserved, -= unimplemented, read as ‘0’.
Shaded cells are not used during Flash/EEPROM access.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 83
PIC18F2331/2431/4331/4431
NOTES:
DS39616B-page 84
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
Control bit CFGS determines if the access will be to the
configuration registers or to program memory/data
EEPROM memory. When set, subsequent operations
access configuration registers. When CFGS is clear,
the EEPGD bit selects either program Flash or data
EEPROM memory.
7.0
DATA EEPROM MEMORY
The Data EEPROM is readable and writable during
normal operation over the entire VDD range. The data
memory is not directly mapped in the register file
space. Instead, it is indirectly addressed through the
Special Function Registers (SFR).
The WREN bit enables and disables erase and write
operations. When set, erase and write operations are
allowed. When clear, erase and write operations are
disabled; the WR bit cannot be set while the WREN bit
is clear. This mechanism helps to prevent accidental
writes to memory due to errant (unexpected) code
execution.
There are four SFRs used to read and write the
program and data EEPROM memory. These registers
are:
• EECON1
• EECON2
• EEDATA
• EEADR
Firmware should keep the WREN bit clear at all times,
except when starting erase or write operations. Once
firmware has set the WR bit, the WREN bit may be
cleared. Clearing the WREN bit will not affect the
operation in progress.
The EEPROM data memory allows byte read and write.
When interfacing to the data memory block, EEDATA
holds the 8-bit data for read/write and EEADR holds the
address of the EEPROM location being accessed.
These devices have 256 bytes of data EEPROM with
an address range from 00h to FFh.
The WRERR bit is set when a write operation is
interrupted by a Reset. In these situations, the user can
check the WRERR bit and rewrite the location. It is
necessary to reload the data and address registers
(EEDATA and EEADR), as these registers have
cleared as a result of the Reset.
The EEPROM data memory is rated for high erase/
write cycle endurance. A byte write automatically
erases the location and writes the new data (erase-
before-write). The write time is controlled by an on-chip
timer. The write time will vary with voltage and temper-
ature, as well as from chip-to-chip. Please refer to
parameter D122 (Table 25-1 in Section 25.0 “Electri-
cal Characteristics”) for exact limits.
Control bits RD and WR start read and erase/write
operations, respectively. These bits are set by firm-
ware, and cleared by hardware at the completion of the
operation.
The RD bit cannot be set when accessing program
memory (EEPGD = 1). Program memory is read using
table read instructions. See Section 6.1 “Table Reads
and Table Writes” regarding table reads.
7.1
EEADR
The address register can address 256 bytes of data
EEPROM.
Note:
Interrupt flag bit, EEIF in the PIR2 register,
is set when write is complete. It must be
cleared in software.
7.2
EECON1 and EECON2 Registers
EECON1 is the control register for memory accesses.
EECON2 is not a physical register. Reading EECON2
will read all ‘0’s. The EECON2 register is used
exclusively in the memory write and erase sequences.
Control bit EEPGD determines if the access will be to
program or data EEPROM memory. When clear, oper-
ations will access the data EEPROM memory. When
set, program memory is accessed.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 85
PIC18F2331/2431/4331/4431
REGISTER 7-1:
EECON1 REGISTER
R/W-x
R/W-x
CFGS
U-0
—
R/W-0
FREE
R/W-x
R/W-0
WREN
R/S-0
WR
R/S-0
RD
EEPGD
WRERR
bit 7
bit 0
bit 7
bit 6
EEPGD: Flash Program or Data EEPROM Memory Select bit
1= Access program Flash memory
0= Access data EEPROM memory
CFGS: Flash Program/Data EE or Configuration Select bit
1= Access configuration or calibration registers
0= Access program Flash or data EEPROM memory
bit 5
bit 4
Unimplemented: Read as ‘0’
FREE: Flash Row Erase Enable bit
1= Erase the program memory row addressed by TBLPTR on the next WR command
(cleared by completion of erase operation)
0= Perform write only
bit 3
WRERR: EEPROM Error Flag bit
1= A write operation was prematurely terminated
(MCLR or WDT Reset during self-timed erase or program operation)
0= The write operation completed normally
Note:
When a WRERR occurs, the EEPGD or FREE bits are not cleared. This allows trac-
ing of the error condition.
bit 2
bit 1
WREN: Erase/Write Enable bit
1= Allows erase/write cycles
0= Inhibits erase/write cycles
WR: Write Control bit
1= Initiates a data EEPROM erase/write cycle or a program memory erase cycle or write
cycle.
(The operation is self-timed and the bit is cleared by hardware once write is complete. The
WR bit can only be set (not cleared) in software.)
0= Write cycle is completed
bit 0
RD: Read Control bit
1= Initiates a memory read
(Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared)
in software. RD bit cannot be set when EEPGD = 1.)
0= Read completed
Legend:
R = Readable bit
W = Writable bit
x = Bit is unknown
S = Settable only
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set ‘0’ = Bit is cleared
- n = Value at POR
DS39616B-page 86
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
After a write sequence has been initiated, EECON1,
EEADR and EEDATA cannot be modified. The WR bit
will be inhibited from being set unless the WREN bit is
7.3
Reading the Data EEPROM
Memory
To read a data memory location, the user must write the
address to the EEADR register, clear the EEPGD con-
trol bit (EECON1<7>) and then set control bit RD
(EECON1<0>). The data is available for the very next
instruction cycle; therefore, the EEDATA register can
be read by the next instruction. EEDATA will hold this
value until another read operation, or until it is written to
by the user (during a write operation).
set. The WREN bit must be set on a previous instruc-
tion. Both WR and WREN cannot be set with the same
instruction.
At the completion of the write cycle, the WR bit is
cleared in hardware and the EEPROM interrupt flag bit
(EEIF) is set. The user may either enable this interrupt
or poll this bit. EEIF must be cleared by software.
7.5
Write Verify
7.4
Writing to the Data EEPROM
Memory
Depending on the application, good programming
practice may dictate that the value written to the mem-
ory should be verified against the original value. This
should be used in applications where excessive writes
can stress bits near the specification limit.
To write an EEPROM data location, the address must
first be written to the EEADR register and the data writ-
ten to the EEDATA register. The sequence in
Example 7-2 must be followed to initiate the write cycle.
The write will not begin if this sequence is not exactly
followed (write 55h to EECON2, write AAh to EECON2,
then set WR bit) for each byte. It is strongly recom-
mended that interrupts be disabled during this
code segment.
7.6
Protection Against Spurious Write
There are conditions when the device may not want to
write to the data EEPROM memory. To protect against
spurious EEPROM writes, various mechanisms have
been built-in. On power-up, the WREN bit is cleared.
Also, the Power-up Timer (72 ms duration) prevents
EEPROM write.
Additionally, the WREN bit in EECON1 must be set to
enable writes. This mechanism prevents accidental
writes to data EEPROM due to unexpected code exe-
cution (i.e., runaway programs). The WREN bit should
be kept clear at all times, except when updating the
EEPROM. The WREN bit is not cleared by hardware.
The write initiate sequence and the WREN bit together
help prevent an accidental write during brown-out,
power glitch, or software malfunction.
EXAMPLE 7-1:
DATA EEPROM READ
MOVLW
MOVWF
BCF
DATA_EE_ADDR
EEADR
EECON1, EEPGD ; Point to DATA memory
;
; Data Memory Address to read
BSF
MOVF
EECON1, RD
EEDATA, W
; EEPROM Read
; W = EEDATA
EXAMPLE 7-2:
DATA EEPROM WRITE
MOVLW
DATA_EE_ADDR
EEADR
DATA_EE_DATA
EEDATA
;
MOVWF
MOVLW
MOVWF
BCF
; Data Memory Address to write
;
; Data Memory Value to write
EECON1, EEPGD ; Point to DATA memory
BSF
BCF
EECON1, WREN
INTCON, GIE
55h
EECON2
AAh
EECON2
EECON1, WR
INTCON, GIE
; Enable writes
; Disable Interrupts
;
; Write 55h
;
; Write AAh
; Set WR bit to begin write
; Enable Interrupts
MOVLW
MOVWF
MOVLW
MOVWF
BSF
Required
Sequence
BSF
SLEEP
BCF
; Wait for interrupt to signal write complete
; Disable writes
EECON1, WREN
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 87
PIC18F2331/2431/4331/4431
7.7
Operation During Code-Protect
7.8
Using the Data EEPROM
Data EEPROM memory has its own code-protect bits in
configuration words. External Read and Write opera-
tions are disabled if either of these mechanisms are
enabled.
The Data EEPROM is a high-endurance, byte
addressable array that has been optimized for the
storage of frequently changing information (e.g.,
program variables or other data that are updated
often). Frequently changing values will typically be
updated more often than specification D124 or D124A.
If this is not the case, an array refresh must be
performed. For this reason, variables that change
infrequently (such as constants, IDs, calibration, etc.)
should be stored in Flash program memory.
The microcontroller itself can both read and write to the
internal data EEPROM, regardless of the state of the
code-protect configuration bit. Refer to Section 22.0
“Special Features of the CPU” for additional
information.
A simple data EEPROM refresh routine is shown in
Example 7-3.
Note:
If data EEPROM is only used to store con-
stants and/or data that changes rarely, an
array refresh is likely not required. See
specification D124 or D124A.
EXAMPLE 7-3:
DATA EEPROM REFRESH ROUTINE
CLRF
BCF
BCF
BCF
BSF
EEADR
; Start at address 0
; Set for memory
; Set for Data EEPROM
; Disable interrupts
; Enable writes
; Loop to refresh array
; Read current address
;
; Write 55h
;
; Write AAh
; Set WR bit to begin write
; Wait for write to complete
EECON1, CFGS
EECON1, EEPGD
INTCON, GIE
EECON1, WREN
LOOP
BSF
EECON1, RD
55h
EECON2
AAh
EECON2
EECON1, WR
EECON1, WR
$-2
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BTFSC
BRA
INCFSZ EEADR, F
; Increment address
BRA
Loop
; Not zero, do it again
BCF
BSF
EECON1, WREN
INTCON, GIE
; Disable writes
; Enable interrupts
TABLE 7-1:
REGISTERS ASSOCIATED WITH DATA EEPROM MEMORY
Value on
all other
Resets
Value on:
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
EEADR
EEDATA
GIE/GIEH PEIE/GIEL TMR0IE
EEPROM Address Register
EEPROM Data Register
INTE
RBIE
TMR0IF
INTF
RBIF
0000 000x 0000 000u
0000 0000 0000 0000
0000 0000 0000 0000
EECON2 EEPROM Control Register2 (not a physical register)
—
—
EECON1
IPR2
EEPGD
OSFIP
OSFIF
OSFIE
CFGS
—
—
—
—
—
FREE
EEIP
EEIF
EEIE
WRERR WREN
WR
—
RD
xx-0 x000 uu-0 u000
—
—
—
LVDIP
LVDIF
LVDIE
CCP2IP 1--1 -1-1 1--1 -1-1
CCP2IF 0--0 -0-0 0--0 -0-0
CCP2IE 0--0 -0-0 0--0 -0-0
PIR2
—
—
PIE2
—
—
Legend:
x= unknown, u= unchanged, r = reserved, -= unimplemented, read as ‘0’.
Shaded cells are not used during Flash/EEPROM access.
DS39616B-page 88
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
Making the 8 x 8 multiplier execute in a single cycle
gives the following advantages:
8.0
8.1
8 X 8 HARDWARE MULTIPLIER
• Higher computational throughput
Introduction
• Reduces code size requirements for multiply
algorithms
An 8 x 8 hardware multiplier is included in the ALU of
the PIC18F2331/2431/4331/4431 devices. By making
the multiply a hardware operation, it completes in a
single instruction cycle. This is an unsigned multiply
that gives a 16-bit result. The result is stored into the
16-bit product register pair (PRODH:PRODL). The
multiplier does not affect any flags in the Status
register.
The performance increase allows the device to be used
in applications previously reserved for Digital Signal
Processors.
Table 8-1 shows a performance comparison between
enhanced devices using the single cycle hardware mul-
tiply, and performing the same function without the
hardware multiply.
TABLE 8-1:
Routine
PERFORMANCE COMPARISON
Program
Time
Cycles
(Max)
Multiply Method
Memory
(Words)
@ 40 MHz @ 10 MHz @ 4 MHz
Without hardware multiply
Hardware multiply
13
1
69
1
6.9 µs
100 ns
9.1 µs
600 ns
24.2 µs
2.4 µs
25.4 µs
3.6 µs
27.6 µs
400 ns
36.4 µs
2.4 µs
69 µs
1 µs
91 µs
6 µs
8 x 8 unsigned
8 x 8 signed
Without hardware multiply
Hardware multiply
33
6
91
6
Without hardware multiply
Hardware multiply
21
24
52
36
242
24
254
36
96.8 µs
9.6 µs
242 µs
24 µs
254 µs
36 µs
16 x 16 unsigned
16 x 16 signed
Without hardware multiply
Hardware multiply
102.6 µs
14.4 µs
EXAMPLE 8-1:
8 x 8 UNSIGNED
MULTIPLY ROUTINE
8.2
Operation
Example 8-1 shows the sequence to do an 8 x 8
unsigned multiply. Only one instruction is required
when one argument of the multiply is already loaded in
the WREG register.
MOVF
ARG1, W
ARG2
;
MULWF
; ARG1 * ARG2 ->
; PRODH:PRODL
Example 8-2 shows the sequence to do an 8 x 8 signed
multiply. To account for the sign bits of the arguments,
each argument’s Most Significant bit (MSb) is tested
and the appropriate subtractions are done.
EXAMPLE 8-2:
8 x 8 SIGNED MULTIPLY
ROUTINE
MOVF
MULWF
ARG1,
ARG2
W
; ARG1 * ARG2 ->
; PRODH:PRODL
BTFSC
SUBWF
ARG2, SB ; Test Sign Bit
PRODH, F ; PRODH = PRODH
- ARG1
;
MOVF
BTFSC
SUBWF
ARG2,
ARG1, SB ; Test Sign Bit
PRODH, F ; PRODH = PRODH
W
;
- ARG2
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 89
PIC18F2331/2431/4331/4431
Example 8-3 shows the sequence to do a 16 x 16
unsigned multiply. Equation 8-1 shows the algorithm
that is used. The 32-bit result is stored in four registers,
RES3:RES0.
EQUATION 8-2:
16 x 16 SIGNED
MULTIPLICATION
ALGORITHM
RES3:RES0
=
=
ARG1H:ARG1L • ARG2H:ARG2L
(ARG1H • ARG2H • 216)+
EQUATION 8-1:
16 x 16 UNSIGNED
MULTIPLICATION
ALGORITHM
(ARG1H • ARG2L • 28)+
(ARG1L • ARG2H ² 28)+
(ARG1L • ARG2L)+
RES3:RES0
=
=
ARG1H:ARG1L • ARG2H:ARG2L
(ARG1H • ARG2H • 216)+
(ARG1H • ARG2L • 28)+
(ARG1L • ARG2H • 28)+
(ARG1L • ARG2L)
(-1 • ARG2H<7> • ARG1H:ARG1L • 216)+
(-1 • ARG1H<7> • ARG2H:ARG2L • 216)
EXAMPLE 8-4:
16 x 16 SIGNED
MULTIPLY ROUTINE
EXAMPLE 8-3:
16 x 16 UNSIGNED
MULTIPLY ROUTINE
MOVF
MULWF
ARG1L,
ARG2L
W
; ARG1L * ARG2L ->
; PRODH:PRODL
MOVFARG1L, W
MULWFARG2L
MOVFF
MOVFF
PRODH, RES1
PRODL, RES0
;
;
; ARG1L * ARG2L ->
; PRODH:PRODL
;
;
;
;
MOVFFPRODH,RES1
MOVFFPRODL,RES0
MOVF
MULWF
ARG1H,
ARG2H
W
; ARG1H * ARG2H ->
; PRODH:PRODL
;
;
;
;
MOVFARG1H,
MULWFARG2H
W
MOVFF
MOVFF
PRODH, RES3
PRODL, RES2
; ARG1H * ARG2H ->
; PRODH:PRODL
MOVFFPRODH,RES3
MOVFFPRODL,RES2
;
;
MOVF
MULWF
ARG1L,
ARG2H
W
; ARG1L * ARG2H ->
; PRODH:PRODL
MOVFARG1L,
MULWFARG2H
W
MOVF
ADDWF
MOVF
ADDWFC RES2,
CLRF WREG
ADDWFC RES3,
PRODL,
RES1,
PRODH,
W
F
W
F
;
; ARG1L * ARG2H ->
; PRODH:PRODL
;
; Add cross
; products
;
;
;
; Add cross
; products
;
;
;
MOVFPRODL,
ADDWFRES1,
MOVFPRODH,
ADDWFCRES2,F
CLRFWREG
W
F
W
F
W
;
MOVF
MULWF
ARG1H,
ARG2L
;
ADDWFCRES3,F
; ARG1H * ARG2L ->
;
; PRODH:PRODL
MOVFARG1H,
MULWFARG2L
W
;
MOVF
ADDWF
MOVF
ADDWFC RES2,
CLRF WREG
ADDWFC RES3,
PRODL,
RES1,
PRODH,
W
F
W
F
;
; ARG1H * ARG2L ->
; PRODH:PRODL
;
; Add cross
; products
;
;
;
; Add cross
; products
;
;
;
MOVFPRODL,
ADDWFRES1,
MOVFPRODH,
ADDWFCRES2,F
CLRFWREG
W
F
W
F
7
;
;
BTFSS
BRA
MOVF
SUBWF
MOVF
ARG2H,
SIGN_ARG1
ARG1L,
RES2
ARG1H,
; ARG2H:ARG2L neg?
; no, check ARG1
;
;
;
ADDWFCRES3,F
W
W
SUBWFB RES3
Example 8-4 shows the sequence to do a 16 x 16
signed multiply. Equation 8-2 shows the algorithm
used. The 32-bit result is stored in four registers,
RES3:RES0. To account for the sign bits of the argu-
ments, each argument pair’s Most Significant bit (MSb)
is tested, and the appropriate subtractions are done.
SIGN_ARG1
BTFSS
BRA
ARG1H,
CONT_CODE
ARG2L,
RES2
ARG2H,
7
; ARG1H:ARG1L neg?
; no, done
;
;
;
MOVF
SUBWF
MOVF
W
W
SUBWFB RES3
;
CONT_CODE
:
DS39616B-page 90
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
When the IPEN bit is cleared (default state), the inter-
rupt priority feature is disabled and interrupts are com-
9.0
INTERRUPTS
patible with PICmicro® mid-range devices. In
Compatibility mode, the interrupt priority bits for each
source have no effect. INTCON<6> is the PEIE bit,
which enables/disables all peripheral interrupt sources.
INTCON<7> is the GIE bit, which enables/disables all
interrupt sources. All interrupts branch to address
000008h in Compatibility mode.
The PIC18F2331/2431/4331/4431 devices have
multiple interrupt sources and an interrupt priority
feature that allows each interrupt source to be assigned
a high priority level or a low priority level. The high
priority interrupt vector is at 000008h and the low
priority interrupt vector is at 000018h. High priority
interrupt events will interrupt any low priority interrupts
that may be in progress.
When an interrupt is responded to, the Global Interrupt
Enable bit is cleared to disable further interrupts. If the
IPEN bit is cleared, this is the GIE bit. If interrupt priority
levels are used, this will be either the GIEH or GIEL bit.
High priority interrupt sources can interrupt a low
priority interrupt. Low priority interrupts are not
processed while high priority interrupts are in progress.
There are ten registers which are used to control
interrupt operation. These registers are:
• RCON
• INTCON
• INTCON2
• INTCON3
The return address is pushed onto the stack and the
PC is loaded with the interrupt vector address
(000008h or 000018h). Once in the interrupt service
routine, the source(s) of the interrupt can be
determined by polling the interrupt flag bits. The
interrupt flag bits must be cleared in software before re-
enabling interrupts to avoid recursive interrupts.
• PIR1, PIR2, PIR3
• PIE1, PIE2, PIE3
• IPR1, IPR2, IPR3
It is recommended that the Microchip header files sup-
plied with MPLAB® IDE be used for the symbolic bit
names in these registers. This allows the assembler/
compiler to automatically take care of the placement of
these bits within the specified register.
The “return from interrupt” instruction, RETFIE, exits
the interrupt routine and sets the GIE bit (GIEH or GIEL
if priority levels are used), which re-enables interrupts.
In general, each interrupt source has three bits to con-
trol its operation. The functions of these bits are:
For external interrupt events, such as the INT pins or
the PORTB input change interrupt, the interrupt latency
will be three to four instruction cycles. The exact
latency is the same for one or two-cycle instructions.
Individual interrupt flag bits are set, regardless of the
status of their corresponding enable bit or the GIE bit.
• Flag bit to indicate that an interrupt event
occurred
• Enable bit that allows program execution to
branch to the interrupt vector address when the
flag bit is set
• Priority bit to select high priority or low priority
(most interrupt sources have priority bits)
Note:
Do not use the MOVFFinstruction to modify
any of the interrupt control registers while
any interrupt is enabled. Doing so may
cause erratic microcontroller behavior.
The interrupt priority feature is enabled by setting the
IPEN bit (RCON<7>). When interrupt priority is
enabled, there are two bits which enable interrupts
globally. Setting the GIEH bit (INTCON<7>) enables all
interrupts that have the priority bit set (high priority).
Setting the GIEL bit (INTCON<6>) enables all
interrupts that have the priority bit cleared (low priority).
When the interrupt flag, enable bit and appropriate
global interrupt enable bit are set, the interrupt will
vector immediately to address 000008h or 000018h,
depending on the priority bit setting. Individual
interrupts can be disabled through their corresponding
enable bits.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 91
PIC18F2331/2431/4331/4431
FIGURE 9-1:
INTERRUPT LOGIC
Wake-up if in
Power-Managed mode
TMR0IF
TMR0IE
TMR0IP
RBIF
RBIE
RBIP
INT0IF
INT0IE
Interrupt to CPU
Vector to Location
0008h
INT1IF
INT1IE
INT1IP
INT2IF
INT2IE
INT2IP
PSPIF
PSPIE
PSPIP
GIEH/GIE
ADIF
ADIE
ADIP
IPE
IPEN
GIEL/PEIE
RCIF
RCIE
RCIP
IPEN
Additional Peripheral Interrupts
High Priority Interrupt Generation
Low Priority Interrupt Generation
PSPIF
PSPIE
PSPIP
Interrupt to CPU
Vector to Location
0018h
TMR0IF
TMR0IE
TMR0IP
ADIF
ADIE
ADIP
RBIF
RBIE
RBIP
RCIF
RCIE
RCIP
GIEL\PEIE
INT0IF
INT0IE
INT1IF
INT1IE
INT1IP
Additional Peripheral Interrupts
INT2IF
INT2IE
INT2IP
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9.1
INTCON Registers
Note:
Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the global
enable bit. User software should ensure
the appropriate interrupt flag bits are clear
prior to enabling an interrupt. This feature
allows for software polling.
The INTCON Registers are readable and writable
registers, which contain various enable, priority and
flag bits.
REGISTER 9-1:
INTCON REGISTER
R/W-0 R/W-0
R/W-0
R/W-0
R/W-0
RBIE
R/W-0
R/W-0
INT0IF
R/W-x
RBIF
bit 0
GIE/GIEH PEIE/GIEL
bit 7
TMR0IE
INT0IE
TMR0IF
bit 7
GIE/GIEH: Global Interrupt Enable bit
When IPEN = 0:
1= Enables all unmasked interrupts
0= Disables all interrupts
When IPEN = 1:
1= Enables all high priority interrupts
0= Disables all high priority interrupts
bit 6
PEIE/GIEL: Peripheral Interrupt Enable bit
When IPEN = 0:
1= Enables all unmasked peripheral interrupts
0= Disables all peripheral interrupts
When IPEN = 1:
1= Enables all low priority peripheral interrupts
0= Disables all low priority peripheral interrupts
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
TMR0IE: TMR0 Overflow Interrupt Enable bit
1= Enables the TMR0 overflow interrupt
0= Disables the TMR0 overflow interrupt
INT0IE: INT0 External Interrupt Enable bit
1= Enables the INT0 external interrupt
0= Disables the INT0 external interrupt
RBIE: RB Port Change Interrupt Enable bit
1= Enables the RB port change interrupt for RB7:RB4 pins
0= Disables the RB port change interrupt for RB7:RB4 pins
TMR0IF: TMR0 Overflow Interrupt Flag bit
1= TMR0 register has overflowed (must be cleared in software)
0= TMR0 register did not overflow
INT0IF: INT0 External Interrupt Flag bit
1= The INT0 external interrupt occurred (must be cleared in software)
0= The INT0 external interrupt did not occur
RBIF: RB Port Change Interrupt Flag bit
1= At least one of the RB7:RB4 pins changed state (must be cleared in software)
0= None of the RB7:RB4 pins have changed state
Note:
A mismatch condition will continue to set this bit. Reading PORTB will end the
mismatch condition and allow the bit to be cleared.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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REGISTER 9-2:
INTCON2 REGISTER
R/W-1
RBPU
R/W-1
R/W-1
R/W-1
U-0
—
R/W-1
U-0
—
R/W-1
RBIP
INTEDG0 INTEDG1 INTEDG2
TMR0IP
bit 7
bit 0
bit 7
bit 6
bit 5
bit 4
RBPU: PORTB Pull-up Enable bit
1= All PORTB pull-ups are disabled
0= PORTB pull-ups are enabled by individual port latch values
INTEDG0: External Interrupt0 Edge Select bit
1= Interrupt on rising edge
0= Interrupt on falling edge
INTEDG1: External Interrupt1 Edge Select bit
1= Interrupt on rising edge
0= Interrupt on falling edge
INTEDG2: External Interrupt2 Edge Select bit
1= Interrupt on rising edge
0= Interrupt on falling edge
bit 3
bit 2
Unimplemented: Read as ‘0’
TMR0IP: TMR0 Overflow Interrupt Priority bit
1= High priority
0= Low priority
bit 1
bit 0
Unimplemented: Read as ‘0’
RBIP: RB Port Change Interrupt Priority bit
1= High priority
0= Low priority
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
Note:
Interrupt flag bits are set when an interrupt condition occurs, regardless of the state
of its corresponding enable bit or the global enable bit. User software should ensure
the appropriate interrupt flag bits are clear prior to enabling an interrupt. This feature
allows for software polling.
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REGISTER 9-3:
INTCON3 REGISTER
R/W-1
R/W-1
U-0
—
R/W-0
R/W-0
U-0
—
R/W-0
INT2IF
R/W-0
INT1IF
INT2IP
INT1IP
INT2IE
INT1IE
bit 7
bit 0
bit 7
bit 6
INT2IP: INT2 External Interrupt Priority bit
1= High priority
0= Low priority
INT1IP: INT1 External Interrupt Priority bit
1= High priority
0= Low priority
bit 5
bit 4
Unimplemented: Read as ‘0’
INT2IE: INT2 External Interrupt Enable bit
1= Enables the INT2 external interrupt
0= Disables the INT2 external interrupt
bit 3
INT1IE: INT1 External Interrupt Enable bit
1= Enables the INT1 external interrupt
0= Disables the INT1 external interrupt
bit 2
bit 1
Unimplemented: Read as ‘0’
INT2IF: INT2 External Interrupt Flag bit
1= The INT2 external interrupt occurred (must be cleared in software)
0= The INT2 external interrupt did not occur
bit 0
INT1IF: INT1 External Interrupt Flag bit
1= The INT1 external interrupt occurred (must be cleared in software)
0= The INT1 external interrupt did not occur
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
Note:
Interrupt flag bits are set when an interrupt condition occurs, regardless of the state
of its corresponding enable bit or the global enable bit. User software should ensure
the appropriate interrupt flag bits are clear prior to enabling an interrupt. This feature
allows for software polling.
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9.2
PIR Registers
Note 1: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the global
enable bit, GIE (INTCON<7>).
The PIR registers contain the individual flag bits for the
peripheral interrupts. Due to the number of peripheral
interrupt sources, there are two Peripheral Interrupt
Flag Registers (PIR1, PIR2).
2: User software should ensure the appropri-
ate interrupt flag bits are cleared prior to
enabling an interrupt, and after servicing
that interrupt.
REGISTER 9-4:
PIR1: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 1
U-0
—
R/W-0
ADIF
R-0
R-0
R/W-0
SSPIF
R/W-0
R/W-0
R/W-0
TMR1IF
bit 0
RCIF
TXIF
CCP1IF
TMR2IF
bit 7
bit 7
bit 6
Unimplemented: Read as ‘0’.
ADIF: A/D Converter Interrupt Flag bit
1= An A/D conversion completed (must be cleared in software)
0= The A/D conversion is not complete
bit 5
bit 4
bit 3
bit 2
RCIF: USART Receive Interrupt Flag bit
1= The USART receive buffer, RCREG, is full (cleared when RCREG is read)
0= The USART receive buffer is empty
TXIF: USART Transmit Interrupt Flag bit
1= The USART transmit buffer, TXREG, is empty (cleared when TXREG is written)
0= The USART transmit buffer is full
SSPIF: Synchronous Serial Port Interrupt Flag bit
1= The transmission/reception is complete (must be cleared in software)
0= Waiting to transmit/receive
CCP1IF: CCP1 Interrupt Flag bit
Capture mode:
1= A TMR1 register capture occurred (must be cleared in software)
0= No TMR1 register capture occurred
Compare mode:
1= A TMR1 register compare match occurred (must be cleared in software)
0= No TMR1 register compare match occurred
PWM mode:
Unused in this mode
bit 1
bit 0
TMR2IF: TMR2 to PR2 Match Interrupt Flag bit
1= TMR2 to PR2 match occurred (must be cleared in software)
0= No TMR2 to PR2 match occurred
TMR1IF: TMR1 Overflow Interrupt Flag bit
1= TMR1 register overflowed (must be cleared in software)
0= TMR1 register did not overflow
Note 1: This bit is reserved on PIC18F2X31 devices; always maintain this bit clear.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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REGISTER 9-5:
PIR2: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 2
R/W-0
OSFIF
U-0
—
U-0
—
R/W-0
EEIF
U-0
—
R/W-0
LVDIF
U-0
—
R/W-0
CCP2IF
bit 0
bit 7
bit 7
OSFIF: Oscillator Fail Interrupt Flag bit
1= System Oscillator failed, clock input has changed to INTOSC (must be cleared in software)
0= System clock operating
bit 6-5 Unimplemented: Read as ‘0’
bit 4
EEIF: EEPROM or Flash Write Operation Interrupt Flag bit
1= The write operation is complete (must be cleared in software)
0= The write operation is not complete or has not been started
bit 3
bit 2
Unimplemented: Read as ‘0’
LVDIF: Low-Voltage Detect Interrupt Flag bit
1= The supply voltage has fallen below the specified LVD voltage (must be cleared in
software)
0= The supply voltage is greater than the specified LVD voltage
bit 1
bit 0
Unimplemented: Read as ‘0’
CCP2IF: CCP2 Interrupt Flag bit
Capture mode:
1= A TMR1 register capture occurred (must be cleared in software)
0= No TMR1 register capture occurred
Compare mode:
1= A TMR1 register compare match occurred (must be cleared in software)
0= No TMR1 register compare match occurred
PWM mode:
Not used in PWM mode
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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REGISTER 9-6:
PIR3: PERIPHERAL INTERRUPT FLAG REGISTER 3
U-0
—
U-0
—
U-0
—
R/W-0
PTIF
R/W-0
R/W-0
R/W-0
IC1IF
R/W-0
IC3DRIF IC2QEIF
TMR5IF
bit 7
bit 0
bit 7-5 Unimplemented: Read as ‘0’
bit 4
bit 3
PTIF: PWM Time Base Interrupt bit
1= PWM Time Base matched the value in PTPER register. Interrupt is issued according to the
postscaler settings. PTIF must be cleared in software.
0= PWM Time Base has not matched the value in PTPER register.
IC3DRIF: IC3 Interrupt Flag/Direction Change Interrupt Flag bit
IC3 Enabled (CAP3CON<3:0>)
1= TMR5 value was captured by the active edge on CAP3 input (must be cleared in software).
0= TMR5 capture has not occurred.
QEI Enabled (QEIM<2:0>)
1= Direction of rotation has changed (must be cleared in software).
0= Direction of rotation has not changed.
bit 2
bit 1
bit 0
IC2QEIF: IC2 Interrupt Flag/QEI Interrupt Flag bit
IC2 Enabled (CAP2CON<3:0>)
1= TMR5 value was captured by the active edge on CAP2 input (must be cleared in software).
0= TMR5 capture has not occurred.
QEI Enabled (QEIM<2:0>)
1= The QEI position counter has reached the MAXCNT value or the index pulse, INDX, has
been detected. Depends on the QEI operating mode enabled. Must be cleared in software.
0= The QEI position counter has not reached the MAXCNT value or the index pulse has not
been detected.
IC1IF: IC1 Interrupt Flag bit
IC1 Enabled (CAP1CON<3:0>)
1= TMR5 value was captured by the active edge on CAP1 input (must be cleared in software).
0= TMR5 capture has not occurred.
QEI Enabled (QEIM<2:0>) and Velocity Measurement mode enabled
(VELM = 0in QEICON Register)
1= Timer5 value was captured by the active velocity edge (based on PHA or PHB input).
CAP1REN bit must be set in CAP1CON register. IC1IF must be cleared in software.
0= Timer5 value was not captured by the active velocity edge.
TMR5IF: Timer5 Interrupt Flag bit
1= Timer5 time base matched the PR5 value (must be cleared in software).
0= Timer5 time base did not match the PR5 value.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
DS39616B-page 98
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9.3
PIE Registers
The PIE registers contain the individual enable bits for
the peripheral interrupts. Due to the number of peripheral
interrupt sources, there are two Peripheral Interrupt
Enable Registers (PIE1, PIE2). When IPEN = 0, the
PEIE bit must be set to enable any of these peripheral
interrupts.
REGISTER 9-7:
PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
U-0
—
R/W-0
ADIE
R/W-0
RCIE
R/W-0
TXIE
R/W-0
SSPIE
R/W-0
R/W-0
R/W-0
TMR1IE
bit 0
CCP1IE
TMR2IE
bit 7
bit 7
bit 6
Unimplemented: Read as ‘0’
ADIE: A/D Converter Interrupt Enable bit
1= Enables the A/D interrupt
0= Disables the A/D interrupt
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
RCIE: USART Receive Interrupt Enable bit
1= Enables the USART receive interrupt
0= Disables the USART receive interrupt
TXIE: USART Transmit Interrupt Enable bit
1= Enables the USART transmit interrupt
0= Disables the USART transmit interrupt
SSPIE: Synchronous Serial Port Interrupt Enable bit
1= Enables the SSP interrupt
0= Disables the SSP interrupt
CCP1IE: CCP1 Interrupt Enable bit
1= Enables the CCP1 interrupt
0= Disables the CCP1 interrupt
TMR2IE: TMR2 to PR2 Match Interrupt Enable bit
1= Enables the TMR2 to PR2 match interrupt
0= Disables the TMR2 to PR2 match interrupt
TMR1IE: TMR1 Overflow Interrupt Enable bit
1= Enables the TMR1 overflow interrupt
0= Disables the TMR1 overflow interrupt
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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REGISTER 9-8:
PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
R/W-0
OSFIE
U-0
—
U-0
—
R/W-0
EEIE
U-0
—
R/W-0
LVDIE
U-0
—
R/W-0
CCP2IE
bit 7
bit 0
bit 7
OSFIE: Oscillator Fail Interrupt Enable bit
1= Enabled
0= Disabled
bit 6-5
bit 4
Unimplemented: Read as ‘0’
EEIE: Interrupt Enable bit
1= Enabled
0= Disabled
bit 3
bit 2
Unimplemented: Read as ‘0’
LVDIE: Low-Voltage Detect Interrupt Enable bit
1= Enabled
0= Disabled
bit 1
bit 0
Unimplemented: Read as ‘0’
CCP2IE: CCP2 Interrupt Enable bit
1= Enabled
0= Disabled
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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REGISTER 9-9:
PIE3: PERIPHERAL INTERRUPT ENABLE REGISTER 3
U-0
—
U-0
—
U-0
—
R/W-0
PTIE
R/W-0
R/W-0
R/W-0
IC1IE
R/W-0
IC3DRIE IC2QEIE
TMR5IE
bit 7
bit 0
bit 7-5 Unimplemented: Read as ‘0’
bit 4
bit 3
PTIE: PWM Time Base Interrupt Enable bit
1= PTIF enabled
0= PTIF disabled
IC3DRIE: IC3 Interrupt Enable/Direction Change Interrupt Enable bit
IC3 Enabled (CAP3CON<3:0>)
1= IC3 interrupt enabled
0= IC3 interrupt disabled
QEI Enabled (QEIM<2:0>)
1= Change-of-direction interrupt enabled
0= Change-of-direction interrupt disabled
bit 2
IC2QEIE: IC2 Interrupt Flag/QEI Interrupt Flag Enable bit
IC2 Enabled (CAP2CON<3:0>)
1= IC2 interrupt enabled)
0= IC2 interrupt disabled
QEI Enabled (QEIM<2:0>)
1= QEI interrupt enabled
0= QEI interrupt disabled
bit 1
bit 0
IC1IE: IC1 Interrupt Enable bit
1= IC1 interrupt enabled
0= IC1 interrupt disabled
TMR5IE: Timer5 Interrupt Enable bit
1= Timer5 interrupt enabled
0= Timer5 interrupt disabled
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
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9.4
IPR Registers
The IPR registers contain the individual priority bits for
the peripheral interrupts. Due to the number of
peripheral interrupt sources, there are two peripheral
interrupt priority registers (IPR1, IPR2). Using the
priority bits requires that the Interrupt Priority Enable
(IPEN) bit be set.
REGISTER 9-10: IPR1: PERIPHERAL INTERRUPT PRIORITY REGISTER 1
U-0
—
R/W-1
ADIP
R/W-1
RCIP
R/W-1
TXIP
R/W-1
SSPIP
R/W-1
R/W-1
R/W-1
TMR1IP
bit 0
CCP1IP
TMR2IP
bit 7
bit 7
bit 6
Unimplemented: Read as ‘0’
ADIP: A/D Converter Interrupt Priority bit
1= High priority
0= Low priority
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
RCIP: USART Receive Interrupt Priority bit
1= High priority
0= Low priority
TXIP: USART Transmit Interrupt Priority bit
1= High priority
0= Low priority
SSPIP: Synchronous Serial Port Interrupt Priority bit
1= High priority
0= Low priority
CCP1IP: CCP1 Interrupt Priority bit
1= High priority
0= Low priority
TMR2IP: TMR2 to PR2 Match Interrupt Priority bit
1= High priority
0= Low priority
TMR1IP: TMR1 Overflow Interrupt Priority bit
1= High priority
0= Low priority
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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REGISTER 9-11: IPR2: PERIPHERAL INTERRUPT PRIORITY REGISTER 2
R/W-1
OSFIP
U-0
—
U-0
—
R/W-1
EEIP
U-0
—
R/W-1
LVDIP
U-0
—
R/W-1
CCP2IP
bit 7
bit 0
bit 7
OSFIP: Oscillator Fail Interrupt Priority bit
1= High priority
0= Low priority
bit 6-5
bit 4
Unimplemented: Read as ‘0’
EEIP: Interrupt Priority bit
1= High priority
0= Low priority
bit 3
bit 2
Unimplemented: Read as ‘0’
LVDIP: Low-Voltage Detect Interrupt Priority bit
1= High priority
0= Low priority
bit 1
bit 0
Unimplemented: Read as ‘0’
CCP2IP: CCP2 Interrupt Priority bit
1= High priority
0= Low priority
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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REGISTER 9-12: IPR3: PERIPHERAL INTERRUPT PRIORITY REGISTER 3
U-0
bit 7
bit 7-5 Unimplemented: Read as ‘0’
U-0
U-0
R/W-1
PTIP
R/W-1
R/W-1
R/W-1
IC1IP
R/W-1
—
—
IC3DRIP IC2QEIP
TMR5IP
bit 0
bit 4
PTIP: PWM Time Base Interrupt Priority bit
1= High Priority
0= Low Priority
bit 3
IC3DRIP: IC3 Interrupt Priority/Direction Change Interrupt Priority bit
IC3 Enabled (CAP3CON<3:0>)
1= IC3 Interrupt High Priority
0= IC3 Interrupt Low Priority
QEI Enabled (QEIM<2:0>)
1= Change of Direction Interrupt High Priority
0= Change of Direction interrupt Low Priority
bit 2
IC2QEIP: IC2 Interrupt Priority/QEI Interrupt Priority bit
IC2 Enabled (CAP2CON<3:0>)
1= IC2 Interrupt High Priority
0= IC2 Interrupt Low Priority
QEI Enabled (QEIM<2:0>)
1= High Priority
0= Low Priority
bit 1
bit 0
IC1IP: IC1 Interrupt Priority bit
1= High Priority
0= Low Priority
TMR5IP: Timer5 Interrupt Priority bit
1= High Priority
0= Low Priority
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
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9.5
RCON Register
The RCON register contains bits used to determine the
cause of the last Reset or wake-up from power-
managed mode. RCON also contains the bit that
enables interrupt priorities (IPEN).
REGISTER 9-13: RCON REGISTER
R/W-0
IPEN
U-0
—
U-0
—
R/W-1
RI
R-1
TO
R-1
PD
R/W-0
POR
R/W-0
BOR
bit 7
bit 0
bit 7
IPEN: Interrupt Priority Enable bit
1= Enable priority levels on interrupts
0= Disable priority levels on interrupts (PIC16CXXX Compatibility mode)
bit 6-5 Unimplemented: Read as ‘0’
bit 4
bit 3
bit 2
bit 1
bit 0
RI: RESETInstruction Flag bit
For details of bit operation, see Register 5-3
TO: Watchdog Time-out Flag bit
For details of bit operation, see Register 5-3
PD: Power-down Detection Flag bit
For details of bit operation, see Register 5-3
POR: Power-on Reset Status bit
For details of bit operation, see Register 5-3
BOR: Brown-out Reset Status bit
For details of bit operation, see Register 5-3
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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9.6
INTn Pin Interrupts
9.7
TMR0 Interrupt
External interrupts on the RC3/INT0, RC4/INT1 and
RC5/INT2 pins are edge triggered: either rising, if the
corresponding INTEDGx bit is set in the INTCON2
register, or falling, if the INTEDGx bit is clear. When a
valid edge appears on the RC3/INT0 pin, the
corresponding flag bit INTxF is set. This interrupt can
be disabled by clearing the corresponding enable bit
INTxE. Flag bit INTxF must be cleared in software in
the interrupt service routine before re-enabling the
interrupt. All external interrupts (INT0, INT1 and INT2)
can wake-up the processor from the power-managed
modes, if bit INTxE was set prior to going into power-
managed modes. If the global interrupt enable bit GIE
is set, the processor will branch to the interrupt vector
following wake-up.
In 8-bit mode (which is the default), an overflow
(FFh → 00h) in the TMR0 register will set flag bit
TMR0IF. In 16-bit mode, an overflow (FFFFh → 0000h)
in the TMR0H:TMR0L registers will set flag bit TMR0IF.
The interrupt can be enabled/disabled by setting/clear-
ing enable bit TMR0IE (INTCON<5>). Interrupt priority
for Timer0 is determined by the value contained in the
interrupt priority bit TMR0IP (INTCON2<2>). See
Section 11.0 “Timer0 Module” for further details.
9.8
PORTB Interrupt-on-Change
An input change on PORTB<7:4> sets flag bit RBIF
(INTCON<0>). The interrupt can be enabled/disabled
by setting/clearing enable bit, RBIE (INTCON<3>).
Interrupt priority for PORTB interrupt-on-change is
determined by the value contained in the interrupt
priority bit, RBIP (INTCON2<0>).
Interrupt priority for INT1 and INT2 is determined by the
value contained in the interrupt priority bits, INT1IP
(INTCON3<6>) and INT2IP (INTCON3<7>). There is
no priority bit associated with INT0. It is always a high
priority interrupt source.
9.9
Context Saving During Interrupts
During interrupts, the return PC address is saved on
the stack. Additionally, the WREG, Status and BSR
registers are saved on the fast return stack. If a fast
return from interrupt is not used (See Section 5.3
“Fast Register Stack”), the user may need to save the
WREG, Status and BSR registers on entry to the
interrupt service routine. Depending on the user’s
application, other registers may also need to be saved.
Example 9-1 saves and restores the WREG, Status
and BSR registers during an interrupt service routine.
EXAMPLE 9-1:
SAVING STATUS, WREG AND BSR REGISTERS IN RAM
MOVWF
MOVFF
MOVFF
;
W_TEMP
STATUS,STATUS_TEMP
BSR,BSR_TEMP
; W_TEMP is in virtual bank
; STATUS_TEMP located anywhere
; BSR_TMEP located anywhere
; USER ISR CODE
;
MOVFF
MOVF
MOVFF
BSR_TEMP,BSR
W_TEMP,W
STATUS_TEMP, STATUS
; Restore BSR
; Restore WREG
; Restore STATUS
DS39616B-page 106
Preliminary
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10.1 PORTA, TRISA and LATA
Registers
10.0 I/O PORTS
Depending on the device selected and features
enabled, there are up to five ports available. Some pins
of the I/O ports are multiplexed with an alternate
function from the peripheral features on the device. In
general, when a peripheral is enabled, that pin may not
be used as a general purpose I/O pin.
PORTA is a 8-bit wide, bidirectional port. The corre-
sponding data direction register is TRISA. Setting a
TRISA bit (= 1) will make the corresponding PORTA pin
an input (i.e., put the corresponding output driver in a
High-Impedance mode). Clearing a TRISA bit (= 0) will
make the corresponding PORTA pin an output (i.e., put
the contents of the output latch on the selected pin).
Each port has three registers for its operation. These
registers are:
Reading the PORTA register reads the status of the
pins, whereas writing to it, will write to the port latch.
• TRIS register (data direction register)
• PORT register (reads the levels on the pins of the
device)
The Data Latch register (LATA) is also memory mapped.
Read-modify-write operations on the LATA register read
and write the latched output value for PORTA.
• LAT register (output latch)
The data latch (LAT register) is useful for read-modify-
write operations on the value that the I/O pins are
driving.
The RA<2:4> pins are multiplexed with three input
capture pins and Quadrature Encoder Interface pins.
Pins RA6 and RA7 are multiplexed with the main
oscillator pins; they are enabled as oscillator or I/O pins
by the selection of the main oscillator in Configuration
Register 1H (see Section 22.1 “Configuration Bits”
for details). When they are not used as port pins, RA6
and RA7 and their associated TRIS and LAT bits are
read as ‘0’.
A simplified model of a generic I/O port without the
interfaces to other peripherals is shown in Figure 10-1.
FIGURE 10-1:
GENERIC I/O PORT
OPERATION
RD LAT
The other PORTA pins are multiplexed with analog
inputs, the analog VREF+ and VREF- inputs and the com-
parator voltage reference output. The operation of pins
RA3:RA0 and RA5 as A/D converter inputs is selected
by clearing/setting the control bits in the ANSEL0 and
ANSEL1 registers.
Data
Bus
D
Q
I/O pin(1)
WR LAT
or
PORT
CK
Data Latch
Note 1: On a Power-on Reset, RA5:RA0 are con-
figured as analog inputs and read as ‘0’.
D
Q
2: RA5 I/F is available only on 40-pin
WR TRIS
RD TRIS
CK
TRIS Latch
devices (PIC18F4X31).
Input
Buffer
The TRISA register controls the direction of the RA
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISA register are
maintained set when using them as analog inputs.
Q
D
EXAMPLE 10-1:
INITIALIZING PORTA
EN
CLRF
PORTA
LATA
0x3F
; Initialize PORTA by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
RD PORT
CLRF
Note 1: I/O pins have diode protection to VDD and VSS.
MOVLW
MOVWF
MOVLW
; Configure A/D
ANSEL0 ; for digital inputs
0xCF
; Value used to
; initialize data
; direction
MOVWF
TRISA
; Set RA<3:0> as inputs
; RA<5:4> as outputs
2003 Microchip Technology Inc.
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FIGURE 10-2:
BLOCK DIAGRAM OF RA0
FIGURE 10-3:
BLOCK DIAGRAM OF RA1
VDD
P
RD LATA
Data
Bus
RD LATA
Data Bus
D
Q
D
Q
Q
VDD
P
RA1
WR LATA
or
PORTA
Q
CK
WR LATA
or
PORTA
N
CK
Data Latch
Data Latch
VSS
D
Q
Q
N
I/O Pin
D
Q
WR TRISA
CK
Analog
Input
TRIS Latch
WR TRISA
VSS
Analog
Mode
Q
CK
Input
Mode
TRIS Latch
RD TRISA
TTL
TTL
Q
D
RD TRISA
Q
Input
Buffer
EN
D
RD PORTA
EN
To A/D Converter
RD PORTA
To A/D Converter
FIGURE 10-4:
BLOCK DIAGRAM OF RA3:RA2 PINS
VDD
P
RD LATA
Data Bus
D
Q
I/O Pin
WR LATA
or
PORTA
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISA
CK
Analog
Input
Mode
TRIS Latch
Schmitt
Trigger
Input
TTL
RD TRISA
Buffer
Q
D
EN
RD PORTA
To A/D Converter
To CAP1/INDX or CAP2/QEA
DS39616B-page 108
Preliminary
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FIGURE 10-5:
BLOCK DIAGRAM OF RA4
RD LATA
Q
Data
Bus
D
VDD
P
WR LATA
or
PORTA
CK
Q
Data Latch
D
Q
RA4(1)
N
WR TRISA
VSS
CK
Schmitt
Trigger
Input
Q
Analog
TRIS Latch
Input
Buffer
Mode
TTL
Input
Buffer
RD TRISA
Q
D
EN
RD PORTA
To A/D Converter
To CAP3/QEB
Note 1: Open-drain usually available on RA4 has been removed for this device.
2003 Microchip Technology Inc.
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FIGURE 10-6:
BLOCK DIAGRAM OF RA5
FIGURE 10-8:
BLOCK DIAGRAM OF RA7
INTOSC Enable
RD LATA
Data
Bus
Data
Bus
TO
D
Q
OSCILLATOR
RD LATA
VDD
WR LATA
or
PORTA
Q
Data Latch
CK
P
D
Q
VDD
P
WR LATA
or
PORTA
N
I/O
Pin
Q
CK
D
Q
Data Latch
WR TRISA
N
I/O
Pin
VSS
D
Q
Q
CK
Analog
Input
TRIS Latch
VSS
CK
Q
Mode or
LVDIN
INTOSC
w/RA7 Enable
TRIS Latch
Enabled
TTL
Input
Buffer
RD TRISA
TTL
Input
Q
D
RD TRISA
Buffer
EN
Q
D
RD PORTA
EN
To A/D Converter/LVD Module Input
RD PORTA
FIGURE 10-7:
BLOCK DIAGRAM OF RA6
ECRA6 or RCRA6
Enable
Data
Bus
TO
OSCILLATOR
RD LATA
D
Q
VDD
P
WR LATA
or
CK
Q
PORTA
Data Latch
N
I/O
Pin
D
Q
VSS
Q
CK
ECRA6 or
RCRA6
Enable
TRIS Latch
TTL
Input
Buffer
RD TRISA
Q
D
EN
RD PORTA
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TABLE 10-1: PORTA FUNCTIONS
Name
Bit #
Buffer
Function
Input/output or analog input.
Input/output or analog input.
RA0/AN0
RA1/AN1
bit 0
bit 1
bit 2
TTL
TTL
RA2/AN2/VREF-/CAP1/INDX
RA3/AN3/VREF+/CAP2/QEA
RA4/AN4/CAP3/QEB
TTL/ST Input/output, analog input, VREF-, capture input, or QEI Index
input.
bit 3
bit 4
TTL/ST Input/output, analog input, VREF+, capture input, or Quadrature
Channel A input.
TTL/ST Input/output, analog input, capture input, or Quadrature Channel
B input.
RA5/AN5/LVDIN
OSC2/CLKO/RA6
OSC1/CLKI/RA7
bit 5
bit 6
bit 7
TTL
TTL
TTL
Input/output, analog input, or low-voltage detect input.
OSC2, clock output or I/O pin.
OSC1, clock input or I/O pin.
Legend: TTL = TTL input, ST = Schmitt Trigger input
TABLE 10-2: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(1)
(1)
PORTA
RA7
RA6
RA5
RA4
RA3
RA2
RA1
RA0
xx0x 0000 uu0u 0000
xxxx xxxx uuuu uuuu
1111 1111 1111 1111
00-1 0000 00-1 0000
1111 1111 1111 1111
---- ---1 ---- ---1
(1)
(1)
LATA
LATA7
LATA6
LATA Data Output Register
(1)
(1)
TRISA
TRISA7
VCFG1
TRISA6
VCFG0
PORTA Data Direction Register
FIFOEN
BFEMT
BFOVFL
ADPNT1
ADPNT0
ANS0
ADCON1
ANSEL0
ANSEL1
Legend:
—
ANS5
—
(2)
(2)
(2)
ANS7
—
ANS6
—
ANS4
—
ANS3
—
ANS2
—
ANS1
—
(2)
ANS8
x= unknown, u= unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA.
Note 1: RA7:RA6 and their associated latch and data direction bits are enabled as I/O pins based on oscillator
configuration; otherwise, they are read as ‘0’.
2: ANS5 through ANS8 are available only on the PIC18F4X31 devices.
2003 Microchip Technology Inc.
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Four of the PORTB pins (RB7:RB4) have an interrupt-
10.2 PORTB, TRISB and LATB
Registers
on-change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the interrupt-
on-change comparison). The input pins (of RB7:RB4)
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of RB7:RB4
are ORed together to generate the RB port change
interrupt with flag bit, RBIF (INTCON<0>).
PORTB is an 8-bit wide, bidirectional port. The corre-
sponding Data Direction register is TRISB. Setting a
TRISB bit (= 1) will make the corresponding PORTB
pin an input (i.e., put the corresponding output driver in
a High-Impedance mode). Clearing a TRISB bit (= 0)
will make the corresponding PORTB pin an output (i.e.,
put the contents of the output latch on the selected pin).
This interrupt can wake the device from Sleep. The
user, in the interrupt service routine, can clear the
interrupt in the following manner:
The Data Latch register (LATB) is also memory
mapped. Read-modify-write operations on the LATB
register read and write the latched output value for
PORTB.
a) Any read or write of PORTB (except with the
MOVFF (ANY), PORTB instruction). This will
end the mismatch condition.
EXAMPLE 10-2:
INITIALIZING PORTB
b) Clear flag bit RBIF.
CLRF
PORTB
; Initialize PORTB by
; clearing output
; data latches
A mismatch condition will continue to set flag bit RBIF.
Reading PORTB will end the mismatch condition and
allow flag bit RBIF to be cleared.
CLRF
LATB
; Alternate method
; to clear output
; data latches
The interrupt-on-change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt-on-change
feature. Polling of PORTB is not recommended while
using the interrupt-on-change feature.
MOVLW
MOVWF
0xCF
; Value used to
; initialize data
; direction
; Set RB<3:0> as inputs
; RB<5:4> as outputs
; RB<7:6> as inputs
TRISB
RB<0:3> and RB4 pins are multiplexed with the 14-bit
PWM module for PWM<0:3> and PWM5 output. The
RB5 pin can be configured by the configuration bit
PWM4MX as the alternate pin for PWM4 output.
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is
performed by clearing bit RBPU (INTCON2<7>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on a Power-on Reset.
DS39616B-page 112
Preliminary
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FIGURE 10-9:
BLOCK DIAGRAM OF RB3:RB0 PINS
VDD
Weak
RBPU(1)
P
Pull-up
PORT/PWM Select
PWM0,1,2, 3 Data
VDD
P
0
1
RD LATC
Q
Data Bus
D
WR LATB
or
PORTB
RB<3:0>
Pins
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISB
CK
TTL
Input
Buffer
TRIS Latch
RD TRISB
Q
D
EN
RD PORTB
Note 1: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2<7>).
2003 Microchip Technology Inc.
Preliminary
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PIC18F2331/2431/4331/4431
FIGURE 10-10:
BLOCK DIAGRAM OF RB4
VDD
Weak
RBPU(1)
P
Pull-up
PORT/PWM Select
PWM5 Data
VDD
P
0
1
RD LATC
Q
Data Bus
D
WR LATB
or
PORTB
RB4 Pin
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISB
CK
TTL
Input
Buffer
TRIS Latch
RD TRISB
RD LATB
Q
D
EN
Q1
RD PORTB
Set RBIF
Q
D
From other
RB7:RB4 pins
RD PORTB
Q3
EN
Note 1: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2<7>).
DS39616B-page 114
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FIGURE 10-11:
BLOCK DIAGRAM OF RB5
PORT/PWM Select
0
1
PWM4 Data
VDD
P
N
VSS
VDD
RBPU
Weak
Pull-up
P
Data Bus
D
Q
RB5/PGM
WR PORT
Q
CK
Data Latch
D
Q
WR TRIS
CK
TRIS Latch
TTL
Input
Buffer
Schmitt
Trigger
RD TRIS
Q
D
RD PORT
Q1
EN
Set RBIF
Q
D
From other
RB7:RB4 pins
RD Port
Q3
EN
LVP Configuration Bit
1 = Low V Prog Enable
0 = only HV Prog
Enable ICSP
2003 Microchip Technology Inc.
Preliminary
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PIC18F2331/2431/4331/4431
FIGURE 10-12:
BLOCK DIAGRAM OF RB7:RB6 PINS
Enable Debug or ICSP
RBPU(1)
Weak
Pull-up
P
0
1
RD LATB
Enable
Data Bus
D
Q
Q
Debug
RB7/RB6
Pin
BRBx
WR LATB
or
PORTB
CK
0
1
Data Latch
Enable
Debug
D
Q
Q
BTRISx
WR TRISB
CK
TRIS Latch
TTL
Input
Buffer
RD TRISC
Schmitt
Trigger
Q
D
RD PORTB
Enable Debug
or ICSP
Q1
EN
Set RBIF
Q
D
RD PORTB
Q3
From other
RB7:RB4 pins
EN
PGC(2)/PGD(3)
Note 1: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2<7>).
2: PGC is available on RB6.
3: PGD is available on RB7.
DS39616B-page 116
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TABLE 10-3: PORTB FUNCTIONS
Name
Bit #
Buffer
Function
RB0/PWM0
bit 0
TTL(1)
Input/output pin, or PCPWM output PWM0.
Internal software programmable weak pull-up.
RB1/PWM1
bit 1
bit 2
bit 3
bit 4
bit 5
TTL(1)
TTL(1)
TTL(1)
TTL
Input/output pin, or PCPWM output PWM1. Internal software
programmable weak pull-up.
RB2/PWM2
Input/output pin, or PCPWM output PWM2. Internal software
programmable weak pull-up.
RB3/PWM3
Input/output pin, or PCPWM output PWM3.
Internal software programmable weak pull-up.
RB4/KBI0/PWM5
Input/output pin (with interrupt-on-change), or PCPWM output PWM5.
Internal software programmable weak pull-up.
RB5/KBI1/PWM4/
PGM
TTL/ST(2) Input/output pin (with interrupt-on-change) or PCPWM output PWM4.
Internal software programmable weak pull-up.
Low-voltage ICSP enable pin.
RB6/KBI2/PGC
RB7/KBI3/PGD
bit 6
bit 7
TTL/ST(2) Input/output pin (with interrupt-on-change).
Internal software programmable weak pull-up.
Serial programming clock.
TTL/ST(2) Input/output pin (with interrupt-on-change).
Internal software programmable weak pull-up.
Serial programming data.
Legend: TTL = TTL input, ST = Schmitt Trigger input
Note 1: This buffer is a TTL input when configured as digital I/O.
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.
TABLE 10-4: SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PORTB
LATB
RB7
RB6
RB5
RB4
RB3
RB2
RB1
RB0
xxxq qqqq
xxxx xxxx
1111 1111
0000 000x
1111 -1-1
uuuu uuuu
uuuu uuuu
1111 1111
0000 000u
1111 -1-1
11-0 0-00
LATB Data Output Register
TRISB
PORTB Data Direction Register
GIE/GIEH PEIE/GIEL TMR0IE
INTCON
INTCON2
INTCON3
Legend:
INT0IE
RBIE
—
TMR0IF INT0IF
RBIF
RBIP
RBPU
INTEDG0 INTEDG1 INTEDG2
INT1IP INT2IE
TMR0IP
—
—
INT2IP
—
INT1IE
INT2IF
INT1IF 11-0 0-00
x= unknown, u= unchanged, q= value depends on condition. Shaded cells are not used by PORTB.
2003 Microchip Technology Inc.
Preliminary
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External interrupts, IN0, INT1 and INT2, are placed on
RC3, RC4 and RC5 respectively.
10.3 PORTC, TRISC and LATC
Registers
SSP alternate interface pins, SDI/SDA, SCK/SCL and
SDO are placed on RC4, RC5, and RC7 pins respec-
tively.
PORTC is an 8-bit wide, bidirectional port. The corre-
sponding Data Direction register is TRISC. Setting a
TRISC bit (= 1) will make the corresponding PORTC
pin an input (i.e., put the corresponding output driver in
a High-Impedance mode). Clearing a TRISC bit (= 0)
will make the corresponding PORTC pin an output (i.e.,
put the contents of the output latch on the selected pin).
These pins are multiplexed on PORTC and PORTD by
using the SSPMX bit in the CONFIG3L register.
USART pins RX/DT and TX/CK are placed on RC7 and
RC6 respectively.
The Data Latch register (LATC) is also memory
mapped. Read-modify-write operations on the LATC
register read and write the latched output value for
PORTC.
The alternate Timer5 external clock input, T5CKI, and
the alternate TMR0 external clock input, T0CKI, are
placed on RC3 and are multiplexed with the PORTD
(RD0) pin using the EXCLKMX configuration bit in
CONFIG3L. Fault inputs to the 14-bit PWM module,
FLTA and FLTB, are located on RC1 and RC2. FLTA
input on RC1 is multiplexed with RD4 using the
FLTAMX bit.
PORTC is multiplexed with several peripheral functions
(Table 10-5). The pins have Schmitt Trigger input
buffers.
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTC pin. Some
peripherals override the TRIS bit to make a pin an output,
while other peripherals override the TRIS bit to make a
pin an input. The user should refer to the corresponding
peripheral section for the correct TRIS bit settings.
EXAMPLE 10-3:
INITIALIZING PORTC
CLRF
PORTC
; Initialize PORTC by
; clearing output
; data latches
CLRF
LATC
; Alternate method
; to clear output
; data latches
Note: On a Power-on Reset, these pins are
configured as digital inputs.
MOVLW
MOVWF
0xCF
; Value used to
; initialize data
; direction
; Set RC<3:0> as inputs
; RC<5:4> as outputs
; RC<7:6> as inputs
The contents of the TRISC register are affected by
peripheral overrides. Reading TRISC always returns
the current contents, even though a peripheral device
may be overriding one or more of the pins.
TRISC
FIGURE 10-13:
BLOCK DIAGRAM OF RC0
VDD
P
RD LATC
Data Bus
D
Q
WR LATC
or
PORTC
RC0 Pin
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISC
T1 OSC EN
CK
Timer1
Oscillator
TRIS Latch
Schmitt
Trigger
RD TRISC
To RC1 Pin
Q
D
EN
RD PORTC
T1 Clock Input
DS39616B-page 118
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 10-14:
BLOCK DIAGRAM OF RC1
PORT/CCP2 Select
CCP2 Data Out
VDD
P
0
1
To RC0 Pin
RD LATC
Q
Data Bus
D
RC1 Pin
WR LATC
or
PORTC
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISC
CK
TRIS Latch
FLTAMX
Schmitt
Trigger
RD TRISC
Q
D
EN
RD PORTC
CCP2 Input
FLTA input(1)
Note 1: FLTA input is multiplexed with RC1 and RD4 using FLTAMX configuration bit in CONFIG3L register.
FIGURE 10-15:
BLOCK DIAGRAM OF RC2
PORT/CCP1 Select
CCP1 Data Out
VDD
P
0
1
RD LATC
Q
Data Bus
D
RC2 Pin
WR LATC
or
PORTC
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISC
CK
TRIS Latch
Schmitt
Trigger
RD TRISC
Q
D
EN
RD PORTC
CCP1 Input/FLTB input
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 119
PIC18F2331/2431/4331/4431
FIGURE 10-16:
BLOCK DIAGRAM OF RC3
VDD
P
RD LATC
Data Bus
D
Q
Q
RC3 Pin
WR LATC
or
PORTC
CK
Data Latch
N
D
Q
Q
VSS
WR TRISC
CK
TRIS Latch
EXCLKMX_enable(1)
Schmitt
Trigger
RD TRISC
Q
D
EN
RD PORTC
T0CKI/T5CKI Input
Note 1: The T0CKI/T5CKI bit is multiplexed with RD0 when the EXCLKM is enabled (= 1) in the configuration register.
FIGURE 10-17:
BLOCK DIAGRAM OF RC4
PORT/SSP Mode & SSPMX Select
SDA Data Out
VDD
P
0
1
RD LATC
Q
Data Bus
D
RC4 Pin
WR LATC
or
PORTC
CK
Q
Data Latch
N
D
Q
Q
VSS
WR TRISC
SDA Drive
CK
TRIS Latch
SSPMX(1)
Schmitt
Trigger
RD TRISC
Q
D
EN
RD PORTC
SDI/SDA Input
Note 1: The SDI/SDA bits are multiplexed on RD2 and RC4 pins by SSPMX bit in the configuration register.
DS39616B-page 120
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FIGURE 10-18:
BLOCK DIAGRAM OF RC5
I2C™ Mode
PORT/ SSPEN & SSPMX_ Select
SCK/SCL Data Out
VDD
P
0
1
RD LATC
Q
Data Bus
D
WR LATC
or
PORTC
RC5 Pin
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISC
SDO Drive
CK
TRIS Latch
SSPMX(1)
Schmitt
Trigger
RD TRISC
Q
D
EN
RD PORTC
SCL or SCL input
Note 1: SCK/SCL are multiplexed on RD3 and RC5 using SSPMX bit in the configuration register.
FIGURE 10-19:
BLOCK DIAGRAM OF RC6
USART Select
TX Data Out/CK
VDD
P
0
1
RD LATC
Q
Data Bus
D
RC6 Pin
WR LATC
or
PORTC
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISC
CK
TRIS Latch
TTL
Schmitt
Trigger
RD TRISC
USART Select
RD PORTC
Q
D
EN
CK Input
SS input
2003 Microchip Technology Inc.
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FIGURE 10-20:
BLOCK DIAGRAM OF RC6
USART Select (1)
DT Data Out
PORT/(SSPEN * SPI Mode ) Select
SDO Data Out(2)
0
1
0
1
VDD
P
RD LATC
Q
Data Bus
D
RC7 Pin
WR LATC
or
PORTC
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISC
CK
TRIS Latch
Schmitt
Trigger
RD TRISC
USART Select(1)
Q
D
EN
RD PORTC
RX/DT Data Input
Note 1: USART is in Synchronous Master Transmission mode only (SYNC = 1, TXEN = 1).
2: SDO must have its TRISC bit cleared in order to be able to drive RC7.
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TABLE 10-5: PORTC FUNCTIONS
Name
Bit # Buffer Type
Function
RC0/T1OSO/T1CKI
bit 0
bit 1
ST
Input/output port pin or Timer1 oscillator output/Timer1 clock input.
RC1/T1OSI/CCP2/
FLTA
ST/CMOS
Input/output port pin, Timer1 oscillator input, or Capture2 input/
Compare2 output/PWM output when CCP2MX configuration bit is
disabled, or FLTA input.
RC2/CCP1/FLTB
bit 2
bit 3
bit 4
ST
ST
Input/output port pin, Capture1 input/Compare1 output/PWM1 output,
or FLTB input.
RC3/T0CKI/T5CKI/
INT0
Input/output port pin, Timer0 and Timer5 alternate clock input, or
external interrupt 0.
Input/output port pin, SPI Data in, I2C Data I/O, or external interrupt 1.
RC4/INT1/SDI/SDA
ST
ST
RC5/INT2/SCK/SCL bit 5
Input/output port pin or Synchronous Serial Port Clock I/O, or external
interrupt 2.
RC6/TX/CK/SS
bit 6
bit 7
ST
ST
Input/output port pin, EUSART Asynchronous Transmit, EUSART
Synchronous Clock, or SPI Slave Select input.
RC7/RX/DT/SDO
Input/output port pin, EUSART Asynchronous Receive, EUSART
Synchronous Data, or SPI Data out.
Legend: ST = Schmitt Trigger input
TABLE 10-6: SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PORTC
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
1111 1111 1111 1111
0000 000x 0000 000u
1111 -1-1 1111 -1-1
LATC
LATC Data Output Register
TRISC
PORTC Data Direction Register
INTCON GIE/GIEH PEIE/GIEL TMR0IE
INTCON2 RBPU
INTCON3 INT2IP
Legend: x= unknown, u= unchanged
INT0IE
RBIE
—
TMR0IF
TMR0IP
—
INT0IF
—
RBIF
RBIP
INTEDG0 INTEDG1 INTEDG2
INT1IP INT2IE
—
INT1IE
INT2IF
INT1IF 11-0 0-00 11-0 0-00
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PORTD includes PWM<7:6> complementary fourth
10.4 PORTD, TRISD and LATD
Registers
channel PWM outputs. PWM4 is the complementary
output of PWM5 (the third channel), which is multi-
plexed with the RB5 pin. This output can be used as the
alternate output using the PWM4MX configuration bit in
CONFIG3L when the low-voltage programming pin
(PGM) is used on RB5.
Note: PORTD is only available on PIC18F4X31
devices.
PORTD is an 8-bit wide, bidirectional port. The
corresponding Data Direction register is TRISD.
Setting a TRISD bit (= 1) will make the corresponding
PORTD pin an input (i.e., put the corresponding output
driver in a High-Impedance mode). Clearing a TRISD
bit (= 0) will make the corresponding PORTD pin an
output (i.e., put the contents of the output latch on the
selected pin).
RD1, RD2 and RD3 can be used as the alternate out-
put for SDO, SDI/SDA and SCK/SCL using the SSPMX
configuration bit in CONFIG3L.
RD4 an be used as the alternate output for FLTA using
the FLTAMX configuration bit in CONFIG3L.
EXAMPLE 10-4:
INITIALIZING PORTD
The Data Latch register (LATD) is also memory
mapped. Read-modify-write operations on the LATD
register read and write the latched output value for
PORTD.
CLRF
PORTD
; Initialize PORTD by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Value used to
; initialize data
; direction
CLRF
LATD
All pins on PORTD are implemented with Schmitt
Trigger input buffers. Each pin is individually
configurable as an input or output.
MOVLW
MOVWF
0xCF
Note: On a Power-on Reset, these pins are
configured as digital inputs.
TRISD
; Set RD<3:0> as inputs
; RD<5:4> as outputs
; RD<7:6> as inputs
FIGURE 10-21:
BLOCK DIAGRAM OF RD7:RD6 PINS
PORT/PWM Select
PWM6,7 Data Out
VDD
P
0
1
RD LATD
Q
Data Bus
D
RD[7:6] Pin
WR LATD
or
PORTD
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISD
CK
TRIS Latch
RD TRISD
Schmitt
Trigger
Q
D
EN
RD PORTD
DS39616B-page 124
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FIGURE 10-22:
BLOCK DIAGRAM OF RD5
PORT/PWM Select
PWM4 Data Out*
VDD
P
0
1
RD LATD
Q
Data Bus
D
RD5 Pin
WR LATD
or
PORTD
CK
Q
Data Latch
N
D
Q
Q
VSS
WR TRISD
CK
TRIS Latch
RD TRISD
Schmitt
Trigger
Q
D
EN
RD PORTD
FIGURE 10-23:
BLOCK DIAGRAM OF RD4
VDD
P
RD LATD
Data Bus
D
Q
Q
RD4 Pin
WR LATD
or
PORTD
CK
Data Latch
N
D
Q
Q
VSS
WR TRISD
CK
TRIS Latch
RD TRISD
Schmitt
Trigger
FLTAMX(1)
Schmitt
Trigger
Q
D
EN
RD PORTD
FLTA input
Note 1: FLTAMX is located in the configuration register.
2003 Microchip Technology Inc.
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FIGURE 10-24:
BLOCK DIAGRAM OF RD3
I2C™ Mode
PORT/ SSPEN & SSPMX Select
SCK/SCL Data Out
VDD
P
0
1
RD LATD
Data Bus
WR LATD
or
PORTD
D
Q
Q
RD3 Pin
CK
Data Latch
N
D
Q
Q
VSS
WR TRISD
CK
TRIS Latch
(1)
SSPMX
Schmitt
Trigger
RD TRISD
Q
D
EN
RD PORTC
SCK or SCL input
Note 1: SCK/SCL are multiplexed on RD3 and RC5 using SSPMX bit in the configuration register.
FIGURE 10-25:
BLOCK DIAGRAM OF RD2
PORT/SSP Mode & SSPMX Select
SDA Data Out
VDD
P
0
1
RD LATC
Q
Data Bus
D
RD2Pin
WR LATC
or
PORTC
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISC
SDA Drive
CK
TRIS Latch
SSPMX(1)
Schmitt
Trigger
RD TRISC
Q
D
EN
RD PORTC
SDI/SDA Input
Note 1: The SDI/SDA bits are multiplexed on RD2 and RC4 pins by SSPMX bit in the configuration register.
DS39616B-page 126
Preliminary
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FIGURE 10-26:
BLOCK DIAGRAM OF RD1
PORT/SPI Mode & SSPMX Select
SDO Data Out
VDD
P
0
1
RD LATD
Q
Data Bus
D
RD1 Pin
WR LATD
or
PORTD
Q
CK
Data Latch
N
D
Q
Q
VSS
WR TRISD
CK
TRIS Latch
Schmitt
Trigger
RD TRISD
Q
D
EN
RD PORTD
Note 1: The SDO output is multiplexed by SSPMX bit in the configuration register.
FIGURE 10-27:
BLOCK DIAGRAM OF RD0
VDD
P
RD LATD
Data Bus
D
Q
Q
RD0 Pin
WR LATD
or
PORTD
CK
Data Latch
N
D
Q
Q
VSS
WR TRISD
CK
TRIS Latch
SSPMX(1)
Schmitt
Trigger
RD TRISD
Q
D
EN
RD PORTD
T0CKI/T5CKI Input
Note 1: T0CKI/T5CKI are multiplexed by SSPMX bit in the configuration register.
2003 Microchip Technology Inc.
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TABLE 10-7: PORTD FUNCTIONS
Name
Bit #
Buffer Type
Function
RD0/T0CKI/T5CKI
RD1/SDO
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
ST
ST
ST
ST
ST
ST
ST
ST
Input/output port pin.
Input/output port pin.
Input/output port pin.
Input/output port pin.
Input/output port pin.
RD2/SDI/SDA
RD3/SCK/SCL
RD4/FLTA
RD5/PWM4
RD6/PWM6
RD7/PWM7
Input/output port pin, or PCPWM output PWM4.
Input/output port pin, or PCPWM output PWM6.
Input/output port pin, or PCPWM output PWM7.
Legend: ST = Schmitt Trigger input, TTL = TTL input
TABLE 10-8: SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PORTD
LATD
RD7
RD6
RD5
RD4
RD3
RD2
RD1
RD0
xxxx xxxx
xxxx xxxx
1111 1111
uuuu uuuu
uuuu uuuu
1111 1111
LATD Data Output Register
TRISD
Legend:
PORTD Data Direction Register
x= unknown, u= unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by PORTD.
DS39616B-page 128
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The fourth pin of PORTE (MCLR/VPP/RE3) is an input
only pin. Its operation is controlled by the MCLRE con-
figuration bit in Configuration Register 3H
(CONFIG3H<7>). When selected as a port pin
(MCLRE = 0), it functions as a digital input only pin. As
such, it does not have TRIS or LAT bits associated with
10.5 PORTE, TRISE and LATE
Registers
Note:
PORTE is only available on PIC18F4X31
devices.
its operation. Otherwise, it functions as the device’s
master clear input. In either configuration, RE3 also
functions as the programming voltage input during
programming.
PORTE is a 4-bit wide bidirectional port. Three pins
(RE0/AN6, RE1/AN67 and RE2/AN8) are individually
configurable as inputs or outputs. These pins have
Schmitt Trigger input buffers. When selected as an
analog input, these pins will read as ‘0’s.
Note: On a Power-on Reset, RE3 is enabled as a
digital input only if Master Clear functionality
is disabled.
The corresponding Data Direction register is TRISE.
Setting a TRISE bit (= 1) will make the corresponding
PORTE pin an input (i.e., put the corresponding output
driver in a High-Impedance mode). Clearing a TRISE
bit (= 0) will make the corresponding PORTE pin an
output (i.e., put the contents of the output latch on the
selected pin).
EXAMPLE 10-5:
INITIALIZING PORTE
CLRF
PORTE
; Initialize PORTE by
; clearing output
; data latches
CLRF
LATE
; Alternate method
; to clear output
; data latches
TRISE controls the direction of the RE pins, even when
they are being used as analog inputs. The user must
make sure to keep the pins configured as inputs when
using them as analog inputs.
MOVLW
MOVWF
bcf
0x3F
; Configure A/D
; for digital inputs
;
; Value used to
; initialize data
; direction
ANSEL0
ANSEL1, 0
0x03
Note: On a Power-on Reset, RE2:RE0 are
MOVLW
configured as analog inputs.
The Data Latch register (LATE) is also memory
mapped. Read-modify-write operations on the LATE
register read and write the latched output value for
PORTE.
MOVWF
TRISE
; Set RE<0> as input
; RE<1> as output
; RE<2> as input
10.5.1
PORTE IN 28-PIN DEVICES
For PIC18F2X31 devices, PORTE is only available
when master clear functionality is disabled
(CONFIG3H<7> = 0). In these cases, PORTE is a
single bit, input only port comprised of RE3 only. The
pin operates as previously described.
2003 Microchip Technology Inc.
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FIGURE 10-28:
RE2:RE0 BLOCK DIAGRAM
VDD
P
RD LATE
Data Bus
D
Q
Q
RE<0:2>
Pins
WR LATE
or
PORTE
CK
Data Latch
N
D
Q
Q
WR TRISE
VSS
CK
TRIS Latch
Analog
Input
Mode
RD TRISE
Schmitt
Trigger
TTL
Q
D
EN
RD PORTE
To A/D Converter ch. AN6 or AN7 or AN8
FIGURE 10-29:
RE3 BLOCK DIAGRAM
MCLR/VPP/RE3
MCLRE
Data Bus
Schmitt
Trigger
RD TRISE
RD LATE
Latch
Q
D
EN
RD PORTE
High Voltage Detect
Internal MCLR
HV
MCLRE
FILTER
Low Level
MCLR Detect
Note 1: Pin requires special protection due to HV.
DS39616B-page 130
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REGISTER 10-1: TRISE REGISTER
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
R/W-1
R/W-1
R/W-1
TRISE2
TRISE1
TRISE0
bit 7
bit 0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
Unimplemented: Read as ‘0’
Unimplemented: Read as ‘0’
Unimplemented: Read as ‘0’
Unimplemented: Read as ‘0’
Unimplemented: Read as ‘0’
TRISE2: RE2 Direction Control bit
1= Input
0= Output
bit 1
bit 0
TRISE1: RE1 Direction Control bit
1= Input
0= Output
TRISE0: RE0 Direction Control bit
1= Input
0= Output
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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TABLE 10-9:
Name
PORTE FUNCTIONS
Bit #
Buffer Type
Function
Input/output port pin, analog input.
RE0/AN6
bit 0
bit 1
bit 2
bit 3
ST
ST
ST
ST
RE1/AN7
Input/output port pin, analog input.
Input/output port pin, analog input.
RE2/AN8
MCLR/VPP/RE3
Input only port pin or programming voltage input (if MCLR is disabled);
Master Clear input or programming voltage input (if MCLR is
enabled).
Legend: ST = Schmitt Trigger input, TTL = TTL input
TABLE 10-10: SUMMARY OF REGISTERS ASSOCIATED WITH PORTE
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(1)
PORTE
LATE
—
—
—
—
—
—
—
—
RE3
—
RE2
RE1
RE0
---- q000 ---- q000
---- -xxx ---- -uuu
---- -111 ---- -111
1111 1111 1111 1111
---- ---0 ---- ---0
LATE Data Output Register
PORTE Data Direction bits
TRISE
—
—
—
—
—
ANSEL0
ANSEL1
Legend:
ANS7
ANS15
ANS6
ANS14
ANS5
ANS13
ANS4
ANS12
ANS3
ANS11
ANS2
ANS1
ANS9
ANS0
ANS8
ANS10
x= unknown, u= unchanged, – = unimplemented, read as ‘0’, q = value depends on condition.
Shaded cells are not used by PORTE.
Note 1: Implemented only when Master Clear functionality is disabled (CONFIG3H<7> = 0).
DS39616B-page 132
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Figure 11-1 shows a simplified block diagram of the
Timer0 module in 8-bit mode and Figure 11-2 shows a
simplified block diagram of the Timer0 module in 16-bit
11.0 TIMER0 MODULE
The Timer0 module has the following features:
mode.
• Software selectable as an 8-bit or 16-bit timer/
counter
The T0CON register (Register 11-1) is a readable and
writable register that controls all the aspects of Timer0,
including the prescale selection.
• Readable and writable
• Dedicated 8-bit software programmable prescaler
• Clock source selectable to be external or internal
• Interrupt-on-overflow from FFh to 00h in 8-bit
mode and FFFFh to 0000h in 16-bit mode
• Edge select for external clock
REGISTER 11-1: T0CON: TIMER0 CONTROL REGISTER
R/W-1
TMR0ON
bit 7
R/W-1
R/W-1
T0CS
R/W-1
T0SE
R/W-1
PSA
R/W-1
T0PS2
R/W-1
T0PS1
R/W-1
T0PS0
bit 0
T016BIT
bit 7
bit 6
bit 5
bit 4
bit 3
TMR0ON: Timer0 On/Off Control bit
1= Enables Timer0
0= Stops Timer0
T016BIT: Timer0 16-bit Control bit
1= Timer0 is configured as an 8-bit timer/counter
0= Timer0 is configured as a 16-bit timer/counter
T0CS: Timer0 Clock Source Select bit
1= Transition on T0CKI pin
0= Internal instruction cycle clock (CLKO)
T0SE: Timer0 Source Edge Select bit
1= Increment on high-to-low transition on T0CKI pin
0= Increment on low-to-high transition on T0CKI pin
PSA: Timer0 Prescaler Assignment bit
1= TImer0 prescaler is NOT assigned. Timer0 clock input bypasses prescaler.
0= Timer0 prescaler is assigned. Timer0 clock input comes from prescaler output.
bit 2-0 T0PS2:T0PS0: Timer0 Prescaler Select bits
111=1:256 prescale value
110=1:128 prescale value
101=1:64 prescale value
100=1:32 prescale value
011=1:16 prescale value
010=1:8 prescale value
001=1:4 prescale value
000=1:2 prescale value
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
2003 Microchip Technology Inc.
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DS39616B-page 133
PIC18F2331/2431/4331/4431
FIGURE 11-1:
TIMER0 BLOCK DIAGRAM IN 8-BIT MODE
Data Bus
FOSC/4
0
1
8
T0CKI pin
0
Sync with
Internal
Clocks
TMR0
Programmable
Prescaler
1
(2 TCY delay)
T0SE
3
PSA
Set Interrupt
Flag bit TMR0IF
on Overflow
T0PS2, T0PS1, T0PS0
T0CS
Note: Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI maximum prescale.
FIGURE 11-2:
TIMER0 BLOCK DIAGRAM IN 16-BIT MODE
FOSC/4
0
1
T0CKI pin
0
1
Sync with
Internal
Clocks
Set Interrupt
Flag bit TMR0IF
on Overflow
TMR0
High Byte
TMR0L
Programmable
Prescaler
8
(2 TCY delay)
T0SE
3
Read TMR0L
Write TMR0L
T0PS2, T0PS1, T0PS0
T0CS
PSA
8
8
TMR0H
8
Data Bus<7:0>
Note: Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI maximum prescale.
DS39616B-page 134
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11.2.1
SWITCHING PRESCALER
ASSIGNMENT
11.1 Timer0 Operation
Timer0 can operate as a timer or as a counter.
The prescaler assignment is fully under software con-
trol (i.e., it can be changed “on-the-fly” during program
execution).
Timer mode is selected by clearing the T0CS bit. In
Timer mode, the Timer0 module will increment every
instruction cycle (without prescaler). If the TMR0 regis-
ter is written, the increment is inhibited for the following
two instruction cycles. The user can work around this
by writing an adjusted value to the TMR0 register.
11.3 Timer0 Interrupt
The TMR0 interrupt is generated when the TMR0
register overflows from FFh to 00h in 8-bit mode, or
FFFFh to 0000h in 16-bit mode. This overflow sets the
TMR0IF bit. The interrupt can be masked by clearing
the TMR0IE bit. The TMR0IF bit must be cleared in
software by the Timer0 module interrupt service routine
before re-enabling this interrupt. The TMR0 interrupt
cannot awaken the processor from Sleep mode, since
the timer requires clock cycles, even when T0CS is set.
Counter mode is selected by setting the T0CS bit. In
Counter mode, Timer0 will increment, either on every
rising or falling edge of pin RC3/T0CKI. The increment-
ing edge is determined by the Timer0 Source Edge
Select bit (T0SE). Clearing the T0SE bit selects the
rising edge.
When an external clock input is used for Timer0, it must
meet certain requirements. The requirements ensure
the external clock can be synchronized with the internal
phase clock (TOSC). Also, there is a delay in the actual
incrementing of Timer0 after synchronization.
11.4 16-Bit Mode Timer Reads and
Writes
TMR0H is not the high byte of the timer/counter in
16-bit mode, but is actually a buffered version of the
high byte of Timer0 (refer to Figure 11-2). The high byte
of the Timer0 counter/timer is not directly readable nor
writable. TMR0H is updated with the contents of the
high byte of Timer0 during a read of TMR0L. This pro-
vides the ability to read all 16 bits of Timer0 without
having to verify that the read of the high and low byte
were valid due to a rollover between successive reads
of the high and low byte.
11.2 Prescaler
An 8-bit counter is available as a prescaler for the Timer0
module. The prescaler is not readable or writable.
The PSA and T0PS2:T0PS0 bits determine the
prescaler assignment and prescale ratio.
Clearing bit PSA will assign the prescaler to the Timer0
module. When the prescaler is assigned to the Timer0
module, prescale values of 1:2, 1:4, ..., 1:256 are
selectable.
A write to the high byte of Timer0 must also take place
through the TMR0H buffer register. Timer0 high byte is
updated with the contents of TMR0H when a write
occurs to TMR0L. This allows all 16 bits of Timer0 to be
updated at once.
When assigned to the Timer0 module, all instructions
writing to the TMR0 register (e.g., CLRF TMR0, MOVWF
TMR0, BSF TMR0, x....etc.) will clear the prescaler
count.
Note:
Writing to TMR0 when the prescaler is
assigned to Timer0 will clear the prescaler
count, but will not change the prescaler
assignment.
TABLE 11-1: REGISTERS ASSOCIATED WITH TIMER0
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
TMR0L
TMR0H
INTCON
T0CON
Timer0 Module Low Byte Register
Timer0 Module High Byte Register
xxxx xxxx uuuu uuuu
0000 0000 0000 0000
0000 000x 0000 000u
1111 1111 1111 1111
GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE
PSA
TMR0IF INT0IF
T0PS2 T0PS1
RBIF
TMR0ON
T016BIT
T0CS
T0SE
T0PS0
(1)
(1)
TRISA
RA7
RA6
PORTA Data Direction Register
1111 1111 1111 1111
Legend: x= unknown, u= unchanged, –= unimplemented locations read as ‘0’. Shaded cells are not used by Timer0.
Note 1: RA6 and RA7 are enabled as I/O pins depending on the Oscillator mode selected in Configuration Word 1H.
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NOTES:
DS39616B-page 136
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Register 12-1 details the Timer1 control register. This
register controls the Operating mode of the Timer1
module, and contains the Timer1 Oscillator Enable bit
(T1OSCEN). Timer1 can be enabled or disabled by
setting or clearing control bit TMR1ON (T1CON<0>).
12.0 TIMER1 MODULE
The Timer1 module timer/counter has the following
features:
• 16-bit timer/counter
(two 8-bit registers; TMR1H and TMR1L)
The Timer1 oscillator can be used as a secondary clock
source in power-managed modes. When the T1RUN
bit is set, the Timer1 oscillator provides the system
clock. If the Fail-Safe Clock Monitor is enabled and the
Timer1 oscillator fails while providing the system clock,
polling the T1RUN bit will indicate whether the clock is
being provided by the Timer1 oscillator or another
source.
• Readable and writable (both registers)
• Internal or external clock select
• Interrupt-on-overflow from FFFFh to 0000h
• Reset from CCP module special event trigger
• Status of system clock operation
Figure 12-1 is a simplified block diagram of the Timer1
module.
Timer1 can also be used to provide Real-Time Clock
(RTC) functionality to applications with only a minimal
addition of external components and code overhead.
REGISTER 12-1: T1CON: TIMER1 CONTROL REGISTER
R/W-0
RD16
R-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
T1RUN T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON
bit 0
bit 7
bit 7
bit 6
RD16: 16-bit Read/Write Mode Enable bit
1= Enables register read/write of TImer1 in one 16-bit operation
0= Enables register read/write of Timer1 in two 8-bit operations
T1RUN: Timer1 System Clock Status bit
1= System clock is derived from Timer1 oscillator
0= System clock is derived from another source
bit 5-4 T1CKPS1:T1CKPS0: Timer1 Input Clock Prescale Select bits
11=1:8 Prescale value
10=1:4 Prescale value
01=1:2 Prescale value
00=1:1 Prescale value
bit 3
bit 2
T1OSCEN: Timer1 Oscillator Enable bit
1= Timer1 oscillator is enabled
0= Timer1 oscillator is shut-off
The oscillator inverter and feedback resistor are turned off to eliminate power drain.
T1SYNC: Timer1 External Clock Input Synchronization Select bit
When TMR1CS = 1(External Clock):
1= Do not synchronize external clock input
0= Synchronize external clock input
When TMR1CS = 0(Internal Clock):
This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0.
TMR1CS: Timer1 Clock Source Select bit
bit 1
bit 0
1= External clock from pin RC0/T1OSO/T1CKI (on the rising edge)
0= Internal clock (FOSC/4)
TMR1ON: Timer1 On bit
1= Enables Timer1
0= Stops Timer1
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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When TMR1CS = 0, Timer1 increments every instruc-
12.1 Timer1 Operation
tion cycle. When TMR1CS = 1, Timer1 increments on
every rising edge of the external clock input or the
Timer1 oscillator, if enabled.
Timer1 can operate in one of these modes:
• As a timer
• As a synchronous counter
• As an asynchronous counter
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RC1/T1OSI/CCP2/FLTA and RC0/T1OSO/
T1CKI pins become inputs. That is, the
TRISC1:TRISC0 value is ignored, and the pins are
read as ‘0’.
The Operating mode is determined by the Clock Select
bit, TMR1CS (T1CON<1>).
Timer1 also has an internal “Reset input”. This Reset
can be generated by the CCP module (see
Section 15.4.4 “Special Event Trigger”).
FIGURE 12-1:
TIMER1 BLOCK DIAGRAM
CCP Special Event Trigger
TMR1IF
Overflow
Interrupt
Flag Bit
Synchronized
TMR1
CLR
0
Clock Input
TMR1L
TMR1H
T1OSC
1
TMR1ON
On/Off
T1SYNC
1
T1CKI/T1OSO
T1OSI
Synchronize
det
T1OSCEN
Enable
Prescaler
1, 2, 4, 8
FOSC/4
Internal
Clock
(1)
Oscillator
0
2
Peripheral Clocks
T1CKPS1:T1CKPS0
TMR1CS
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
FIGURE 12-2:
TIMER1 BLOCK DIAGRAM: 16-BIT READ/WRITE MODE
Data Bus<7:0>
8
TMR1H
8
8
Write TMR1L
Read TMR1L
CCP Special Event Trigger
0
TMR1IF
Overflow
Interrupt
Synchronized
Clock Input
TMR1
8
CLR
Timer 1
High Byte
TMR1L
Flag bit
1
TMR1ON
T1SYNC
on/off
T1OSC
T1CKI/T1OSO
1
Synchronize
Prescaler
1, 2, 4, 8
T1OSCEN
det
FOSC/4
Internal
Clock
Enable
0
(1)
T1OSI
Oscillator
2
Peripheral Clocks
TMR1CS
T1CKPS1:T1CKPS0
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
DS39616B-page 138
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12.2 Timer1 Oscillator
12.3 Timer1 Oscillator Layout
Considerations
A crystal oscillator circuit is built-in between pins T1OSI
(input) and T1OSO (amplifier output). It is enabled by
setting control bit T1OSCEN (T1CON<3>). The oscilla-
tor is a low-power oscillator rated for 32 kHz crystals. It
will continue to run during all power-managed modes.
The circuit for a typical LP oscillator is shown in
Figure 12-3. Table 12-1 shows the capacitor selection
for the Timer1 oscillator.
The Timer1 oscillator for PIC18F2331/2431/4331/4431
devices incorporates an additional low-power feature.
When this option is selected, it allows the oscillator to
automatically reduce its power consumption when the
microcontroller is in Sleep mode. During normal device
operation, the oscillator draws full current. As high
noise environments may cause excessive oscillator
instability in Sleep mode, this option is best suited for
low noise applications where power conservation is an
important design consideration.
The user must provide a software time delay to ensure
proper start-up of the Timer1 oscillator.
FIGURE 12-3:
EXTERNAL
COMPONENTS FOR THE
TIMER1 LP OSCILLATOR
The low-power option is enabled by clearing the
T1OSCMX bit (CONFIG3L<5>). By default, the option
is disabled, which results in a more-or-less constant
current draw for the Timer1 oscillator.
C1
33 pF
PIC18FXXXX
Due to the low power nature of the oscillator, it may also
be sensitive to rapidly changing signals in close
proximity.
T1OSI
XTAL
32.768 kHz
The oscillator circuit, shown in Figure 12-3, should be
located as close as possible to the microcontroller.
There should be no circuits passing within the oscillator
circuit boundaries other than VSS or VDD.
T1OSO
C2
33 pF
If a high-speed circuit must be located near the oscilla-
tor (such as the CCP1 pin in output compare or PWM
mode, or the primary oscillator using the OSC2 pin), a
grounded guard ring around the oscillator circuit, as
shown in Figure 12-4, may be helpful when used on a
single sided PCB, or in addition to a ground plane.
Note:
See the notes with Table 12-1 for additional
information about capacitor selection.
TABLE 12-1: CAPACITOR SELECTION FOR
THE TIMER OSCILLATOR
FIGURE 12-4:
OSCILLATOR CIRCUIT
WITH GROUNDED GUARD
RING
Osc Type
Freq
C1
C2
LP
32 kHz
27 pF(1)
27 pF(1)
VDD
VSS
Note 1: Microchip suggests this value as a starting
point in validating the oscillator circuit.
2: Higher capacitance increases the stability
of the oscillator, but also increases the
start-up time.
OSC1
OSC2
3: Since each resonator/crystal has its own
characteristics, the user should consult
the resonator/crystal manufacturer for
RC0
RC1
appropriate
values
of
external
components.
4: Capacitor values are for design guidance
only.
RC2
Note: Not drawn to scale.
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12.4 Timer1 Interrupt
12.7 Using Timer1 as a Real-Time
Clock
The TMR1 register pair (TMR1H:TMR1L) increments
from 0000h to FFFFh and rolls over to 0000h. The
Timer1 interrupt, if enabled, is generated on overflow,
which is latched in interrupt flag bit, TMR1IF
(PIR1<0>). This interrupt can be enabled/disabled by
setting/clearing Timer1 interrupt enable bit, TMR1IE
(PIE1<0>).
Adding an external LP oscillator to Timer1 (such as the
one described in Section 12.2 “Timer1 Oscillator”),
gives users the option to include RTC functionality to
their applications. This is accomplished with an
inexpensive watch crystal to provide an accurate time
base, and several lines of application code to calculate
the time. When operating in Sleep mode and using a
battery or supercapacitor as a power source, it can
completely eliminate the need for a separate RTC
device and battery backup.
12.5 Resetting Timer1 Using a CCP
Trigger Output
If the CCP module is configured in Compare mode to
generate a “special event trigger” (CCP1M3:CCP1M0
= 1011), this signal will reset Timer1 and start an A/D
conversion if the A/D module is enabled (see
Section 15.4.4 “Special Event Trigger” for more
information.).
The application code routine RTCisr, shown in
Example 12-1, demonstrates a simple method to
increment a counter at one-second intervals using an
interrupt service routine. Incrementing the TMR1
register pair to overflow triggers the interrupt and calls
the routine, which increments the seconds counter by
one. Additional counters for minutes and hours are
incremented as the previous counter overflow.
Note:
The special event triggers from the CCP1
module will not set interrupt flag bit
TMR1IF (PIR1<0>).
Since the register pair is 16-bits wide, counting up to
overflow the register directly from a 32.768 kHz clock
would take 2 seconds. To force the overflow at the
required one-second intervals, it is necessary to pre-
load it; the simplest method is to set the MSbit of
TMR1H with a BSF instruction. Note that the TMR1L
register is never preloaded or altered; doing so may
introduce cumulative error over many cycles.
Timer1 must be configured for either Timer or Synchro-
nized Counter mode to take advantage of this feature.
If Timer1 is running in Asynchronous Counter mode,
this Reset operation may not work.
In the event that a write to Timer1 coincides with a
special event trigger from CCP1, the write will take
precedence.
For this method to be accurate, Timer1 must operate in
Asynchronous mode, and the Timer1 overflow interrupt
must be enabled (PIE1<0> = 1), as shown in the rou-
tine RTCinit. The Timer1 oscillator must also be
enabled and running at all times.
In this mode of operation, the CCPR1H:CCPR1L regis-
ters pair effectively becomes the period register for
Timer1.
12.6 Timer1 16-Bit Read/Write Mode
Timer1 can be configured for 16-bit reads and writes
(see Figure 12-2). When the RD16 control bit
(T1CON<7>) is set, the address for TMR1H is mapped
to a buffer register for the high byte of Timer1. A read
from TMR1L will load the contents of the high byte of
Timer1 into the Timer1 high byte buffer. This provides
the user with the ability to accurately read all 16 bits of
Timer1 without having to determine whether a read of
the high byte, followed by a read of the low byte, is
valid, due to a rollover between reads.
A write to the high byte of Timer1 must also take place
through the TMR1H buffer register. Timer1 high byte is
updated with the contents of TMR1H when a write
occurs to TMR1L. This allows a user to write all 16 bits
to both the high and low bytes of Timer1 at once.
The high byte of Timer1 is not directly readable or writ-
able in this mode. All reads and writes must take place
through the Timer1 high byte buffer register. Writes to
TMR1H do not clear the Timer1 prescaler. The
prescaler is only cleared on writes to TMR1L.
DS39616B-page 140
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EXAMPLE 12-1:
IMPLEMENTING A REAL-TIME CLOCK USING A TIMER1 INTERRUPT SERVICE
RTCinit
MOVLW
MOVWF
CLRF
0x80
TMR1H
TMR1L
; Preload TMR1 register pair
; for 1 second overflow
MOVLW
MOVWF
CLRF
b’00001111’
T1OSC
secs
; Configure for external clock,
; Asynchronous operation, external oscillator
; Initialize timekeeping registers
;
CLRF
mins
MOVLW
MOVWF
BSF
.12
hours
PIE1, TMR1IE
; Enable Timer1 interrupt
RETURN
RTCisr
BSF
BCF
INCF
MOVLW
TMR1H, 7
PIR1, TMR1IF
secs, F
.59
; Preload for 1 sec overflow
; Clear interrupt flag
; Increment seconds
; 60 seconds elapsed?
CPFSGT secs
RETURN
; No, done
CLRF
INCF
MOVLW
secs
mins, F
.59
; Clear seconds
; Increment minutes
; 60 minutes elapsed?
CPFSGT mins
RETURN
; No, done
CLRF
INCF
MOVLW
mins
hours, F
.23
; clear minutes
; Increment hours
; 24 hours elapsed?
CPFSGT hours
RETURN
; No, done
MOVLW
MOVWF
RETURN
.01
hours
; Reset hours to 1
; Done
TABLE 12-2: REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON GIE/GIEH PEIE/GIEL TMR0IE
INT0IE
TXIF
RBIE
SSPIF
SSPIE
SSPIP
TMR0IF
INT0IF
RBIF
-000 000x 0000 000u
PIR1
—
—
—
ADIF
ADIE
ADIP
RCIF
RCIE
RCIP
CCP1IF TMR2IF TMR1IF -000 0000 -000 0000
CCP1IE TMR2IE TMR1IE -000 0000 -000 0000
CCP1IP TMR2IP TMR1IP 1111 1111 -111 1111
PIE1
TXIE
TXIP
IPR1
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
T1CON RD16
Legend: x= unknown, u= unchanged, –= unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module.
T1RUN T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0000 0000 u0uu uuuu
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NOTES:
DS39616B-page 142
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13.1 Timer2 Operation
13.0 TIMER2 MODULE
Timer2 can be used as the PWM time base for the
PWM mode of the CCP module. The TMR2 register is
readable and writable, and is cleared on any device
Reset. The input clock (FOSC/4) has a prescale option
of 1:1, 1:4 or 1:16, selected by control bits
T2CKPS1:T2CKPS0 (T2CON<1:0>). The match out-
put of TMR2 goes through a 4-bit postscaler (which
gives a 1:1 to 1:16 scaling inclusive) to generate a
TMR2 interrupt (latched in flag bit TMR2IF, (PIR1<1>)).
The Timer2 module timer has the following features:
• 8-bit timer (TMR2 register)
• 8-bit period register (PR2)
• Readable and writable (both registers)
• Software programmable prescaler (1:1, 1:4, 1:16)
• Software programmable postscaler (1:1 to 1:16)
• Interrupt on TMR2 match with PR2
• SSP module optional use of TMR2 output to
generate clock shift
The prescaler and postscaler counters are cleared
when any of the following occurs:
Timer2 has a control register shown in Register 13-1.
TMR2 can be shut off by clearing control bit TMR2ON
(T2CON<2>) to minimize power consumption.
Figure 13-1 is a simplified block diagram of the Timer2
module. Register 13-1 shows the Timer2 control
register. The prescaler and postscaler selection of
Timer2 are controlled by this register.
• A write to the TMR2 register
• A write to the T2CON register
• Any device Reset (Power-on Reset, MCLR Reset,
Watchdog Timer Reset or Brown-out Reset)
TMR2 is not cleared when T2CON is written.
REGISTER 13-1: T2CON: TIMER2 CONTROL REGISTER
U-0
—
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0
bit 0
bit 7
bit 7
Unimplemented: Read as ‘0’
bit 6-3 TOUTPS3:TOUTPS0: Timer2 Output Postscale Select bits
0000= 1:1 Postscale
0001=1:2 Postscale
•
•
•
1111=1:16 Postscale
bit 2
TMR2ON: Timer2 On bit
1= Timer2 is on
0= Timer2 is off
bit 1-0 T2CKPS1:T2CKPS0: Timer2 Clock Prescale Select bits
00= Prescaler is 1
01= Prescaler is 4
1x= Prescaler is 16
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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13.2 Timer2 Interrupt
13.3 Output of TMR2
The Timer2 module has an 8-bit period register, PR2.
Timer2 increments from 00h until it matches PR2 and
then resets to 00h on the next increment cycle. PR2 is
a readable and writable register. The PR2 register is
initialized to FFh upon Reset.
The output of TMR2 (before the postscaler) is fed to the
Synchronous Serial Port module, which optionally uses
it to generate the shift clock.
FIGURE 13-1:
TIMER2 BLOCK DIAGRAM
Sets Flag
TMR2
bit TMR2IF
(1)
Output
Prescaler
Reset
EQ
TMR2
FOSC/4
1:1, 1:4, 1:16
Postscaler
1:1 to 1:16
2
Comparator
PR2
T2CKPS1:T2CKPS0
4
TOUTPS3:TOUTPS0
Note 1: TMR2 register output can be software selected by the SSP module as a baud clock.
TABLE 13-1: REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON GIE/GIEH PEIE/GIEL TMR0IE
INT0IE
TXIF
RBIE
SSPIF
SSPIE
SSPIP
TMR0IF
CCP1IF
INT0IF
RBIF
0000 000x 0000 000u
PIR1
PIE1
—
—
—
ADIF
ADIE
ADIP
RCIF
RCIE
RCIP
TMR2IF
TMR1IF -000 0000 -000 0000
TMR1IE -000 0000 -000 0000
TMR1IP -111 1111 -111 1111
0000 0000 0000 0000
TXIE
TXIP
CCP1IE TMR2IE
CCP1IP TMR2IP
IPR1
TMR2
T2CON
PR2
Timer2 Module Register
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
Timer2 Period Register 1111 1111 1111 1111
Legend: x= unknown, u= unchanged, –= unimplemented read as ‘0’. Shaded cells are not used by the Timer2 module.
DS39616B-page 144
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Timer5 is a general-purpose timer/counter that incorpo-
rates additional features for use with the Motion Feed-
back module (see Section 16.0 “Motion Feedback
Module”). It may also be used as a general-purpose
timer or a special event trigger delay timer. When used
as a general-purpose timer, it can be configured to gen-
erate a delayed special event trigger (e.g., an ADC
special event trigger) using a pre-programmed period
delay.
14.0 TIMER5 MODULE
The Timer5 module implements these features:
• 16-bit timer/counter operation
• Synchronous and asynchronous counter modes
• Continuous and Single-Shot operating modes
• Four programmable prescaler values (1:1 to 1:8)
• Interrupt generated on period match
• Special event trigger Reset function
• Double-buffered registers
Timer5 is controlled through the Timer5 Control Regis-
ter (T5CON), shown in Register 14-1. The timer can be
enabled or disabled by setting or clearing the control bit
TMR5ON (T5CON<0>).
• Operation during Sleep
• CPU wake-up from Sleep
A block diagram of Timer5 is shown in Figure 14-1.
• Selectable hardware Reset input with a wake-up
feature
REGISTER 14-1: T5CON: TIMER5 CONTROL REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
T5PS1
R/W-0
T5PS0
R/W-0
R/W-0
R/W-0
T5SEN
RESEN
T5MOD
T5SYNC TMR5CS TMR5ON
bit 0
bit 7
bit 7
T5SEN: Timer5 Sleep Enable bit(1)
1= Timer5 enabled during Sleep
0= Timer5 disabled during Sleep
bit 6
RESEN: Special Event Reset Enable bit
1= Special Event Reset disabled
0= Special Event Reset enabled
bit 5
T5MOD: Timer5 Mode bit
1= Single-Shot mode enabled
0= Continuous Count mode enabled
bit 4:3
T5PS1:T5PS0: Timer5 Input Clock Prescale Select bits
11=1:8
10=1:4
01=1:2
00=1:1
bit 2
T5SYNC: Timer5 External Clock Input Synchronization Select bit
When TMR5CS = 1:
1= Do not synchronize external clock input
0= Synchronize external clock input
When TMR5CS = 0:
This bit is ignored. Timer5 uses the internal clock when TMR5CS = 0
bit 1
bit 0
TMR5CS: Timer5 Clock Source Select bit
1= External clock from pin T5CKI
0= Internal clock (TCY)
TMR5ON: Timer5 On bit
1= Timer5 enabled
0= Timer5 disabled
Note 1: For Timer5 to operate during Sleep mode, T5SYNC must be set.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
2003 Microchip Technology Inc.
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FIGURE 14-1:
TIMER5 BLOCK DIAGRAM (16-BIT READ/WRITE MODE SHOWN)
T5CKI
Internal Data Bus
1
0
Noise
Filter
1
0
Synchronize
detect
Prescaler
1, 2, 4, 8
FOSC/4
Internal
Clock
2
Sleep Input
Timer5
On/Off
TMR5CS
T5PS1:T5PS0
T5SYNC
TMR5ON
8
8
TMR5H
8
Write TMR5L
Read TMR5L
TMR5
TMR5L
8
Special Event
Trigger Input
from IC1
1
0
TMR5
High Byte
Timer5 Reset
Timer5 Reset
(external)
16
Reset
Logic
Comparator
16
PR5
PR5L
8
8
PR5H
Set TMR5IF
Special
Event
Logic
Special Event
Trigger Output
Timer5 supports three configurations:
14.1 Timer5 Operation
• 16-bit Synchronous Timer
• 16-bit Synchronous Counter
• 16-bit Asynchronous Counter
Timer5 combines two 8-bit registers to function as a 16-
bit timer. The TMR5L register is the actual low byte of
the timer; it can be read and written to directly. The high
byte is contained in an unmapped register; it is read
and written to through TMR5H, which serves as a
buffer. Each register increments from 00h to FFh.
In Synchronous Timer configuration, the timer is
clocked by the internal device clock. The optional
Timer5 prescaler divides the input by 2, 4, 8, or not at
all (1:1). The TMR5 register pair increments on Q1.
Clearing TMR5CS (= 0) selects the internal device
clock as the timer sampling clock.
A second register pair, PR5H and PR5L, serves as a
period register; it sets the maximum count for the
TMR5 register pair. When TMR5 reaches the value of
PR5, the timer rolls over to 00h and sets the TMR5IF
interrupt flag. A simplified block diagram of the Timer5
module is shown in Figure 2-1.
In Synchronous Counter configuration, the timer is
clocked by the external clock (T5CKI) with the optional
prescaler. The external T5CKI is selected by setting the
TMR5CS bit (TMR5CS = 1); the internal clock is
selected by clearing TMR5CS. The external clock is
synchronized to the internal clock by clearing the
T5SYNC bit. The input on T5CKI is sampled on every
Q2 and Q4 of the internal clock. The low to rise
transition is decoded on three adjacent samples and
Note:
The TIMER5 may be used as a general
purpose timer and as the time base
resource to the Motion Feedback module
(Input Capture or Quadrature Encoder
Interface).
DS39616B-page 146
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the Timer5 is incremented on the next Q1. The T5CKI
minimum pulse width high and low time must be
greater than TCY/2.
Since the actual high byte of the Timer5 register pair is
not directly readable or writable, it must be read and
written to through the Timer5 High Byte Buffer register
(TMR5H). The T5 high byte is updated with the con-
tents of TMR5H when a write occurs to TMR5L. This
allows a user to write all 16 bits to both the high and low
bytes of Timer5 at once. Writes to TMR5H do not clear
the Timer5 prescaler. The prescaler is only cleared on
writes to TMR5L.
In Asynchronous Counter configuration, Timer5 is
clocked by the external clock (T5CKI) with the optional
prescaler. In this mode, T5CKI is not synchronized to
the internal clock. By setting TMR5CS, the external
input clock (T5CKI) can be used as the counter sam-
pling clock. When T5SYNC is set, the external clock is
not synchronized to the internal device clock.
14.2.1
16-BIT READ-MODIFY-WRITE
The timer count is not reset automatically when the
module is disabled. The user may write the counter
register to initialize the counter.
Read-modify-write instructions like BSF and BCF will
read the contents of a register, make the appropriate
changes, and place the result back into the register.
The write portion of a read-modify-write instruction of
TMR5H will not update the contents of the high byte of
TMR5 until a write of TMR5L takes place. Only then will
the contents of TMR5H be placed into the high byte of
TMR5.
Note:
The Timer5 module does NOT prevent
writes to the PR5 registers (PR5H:PR5L)
while the timer is enabled. Writing to PR5
while the timer is enabled may result in
unexpected period match events.
14.1.1
CONTINUOUS AND SINGLE-SHOT
OPERATION
14.3 Timer5 Prescaler
The Timer5 clock input (either TCY or the external clock)
may be divided by using the Timer5 programmable
prescaler. The prescaler control bits T5PS1:T5PS0
(T5CON<4:3>) select a prescale factor of 2, 4, 8 or no
prescale.
Timer5 has two operating modes: Continuous-count
and Single-shot.
Continuous-count mode is selected by clearing the
T5MOD control bit (= 0). In this mode, the Timer5 time
base will start incrementing according to the prescaler
settings until a TMR5/PR5 match occurs, or until TMR5
rolls over (FFFFh to 0000h). The TMR5IF interrupt flag
is set, the TMR5 register is reset on the following input
clock edge, and the timer continues to count for as long
as the TMR5ON bit remains set.
The Timer5 prescaler is cleared by any of the following:
• A write to the Timer5 register
• Disabling Timer5 (TMR5ON = 0)
• A device Reset such as Master Clear, POR or
BOR
Single-shot mode is selected by setting T5MOD (= 1).
In this mode, the Timer5 time base begins to increment
according to the prescaler settings until a TMR5/PR5
match occurs. This causes the TMR5IF interrupt flag to
be set, the TMR5 register pair to be cleared on the
following input clock edge, and the TMR5ON bit to be
cleared by the hardware to halt the timer.
Note:
Writing to the T5CON register does not
clear the Timer5.
14.4 Noise Filter
The Timer5 module includes an optional input noise
filter, designed to reduce spurious signals in noisy
operating environments. The filter ensures that the
input is not permitted to change until a stable value has
been registered for three consecutive sampling clock
cycles.
The Timer5 time base can only start incrementing in
Single-shot mode under two conditions:
1. Timer5 is enabled (TMR5ON is set), or
2. Timer5 is disabled, and a Special Event Reset
trigger is present on the Timer5 reset input. (See
Section 14.7 “Timer5 Special Event Reset
Input” for additional information).
The noise filter is part of the input filter network associ-
ated with the Motion Feedback Module (see
Section 16.0 “Motion Feedback Module”). All of the
filters are controlled using the Digital Filter Control
(DFLTCON) register (Register 16-3). The Timer5 filter
can be individually enabled or disabled by setting or
clearing the FLT4EN bit (DFLTCON<7>). It is disabled
on all BOR and BOR resets.
14.2 16-bit Read/Write and Write Modes
As noted, the actual high byte of the Timer5 register
pair is mapped to TMR5H, which serves as a buffer.
Reading TMR5L will load the contents of the high byte
of the register pair into the TMR5H register. This allows
the user to accurately read all 16 bits of the register
pair, without having to determine whether a read of the
high byte followed by the low byte is valid due to a
rollover between reads.
For additional information, refer to Section 16.3
“Noise Filters” in the Motion Feedback module.
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14.7.2
DELAYED-ACTION EVENT
TRIGGER
14.5 Timer5 Interrupt
Timer5 has the ability to generate an interrupt on a
period match. When the PR5 register is loaded with a
new period value (00FFh), the Timer5 time base incre-
ments until its value is equal to the value of PR5. When
a match occurs, the Timer5 interrupt is generated on
the rising edge of Q4; TMR5IF is set on the next TCY.
An active edge on CAP1 can also be used to initiate
some later action delayed by the Timer5 time base. In
this case, Timer5 increments as before after being
triggered. When the hardware time-out occurs, the
special event trigger output is generated and used to
trigger another action, such as an A/D conversion. This
allows a given hardware action to be referenced from a
capture edge on CAP1 and delayed by the timer.
The interrupt latency (i.e., the time elapsed from the
moment Timer5 rolls over until TMR5IF is set) will not
exceed 1 TCY. When the Timer5 clock input is
prescaled and a TMR5/PR5 match occurs, the interrupt
will be generated on the first Q4 rising edge after TMR5
resets.
The event timing for the delayed action event trigger is
discussed further in Section 16.1 “Input Capture”.
14.7.3
SPECIAL EVENT RESET WHILE
TIMER5 IS INCREMENTING
14.6 Timer5 Special Event Trigger
Output
In the event that a bus write to Timer5 coincides with a
Special Event Reset trigger, the bus write will always
take precedence over Special Event Reset trigger.
A Timer5 special event trigger is generated on a TMR5/
PR5 match. The special event trigger is generated on
the falling edge of Q3.
14.8 Operation in Sleep Mode
Timer5 must be configured for either Synchronous
mode (counter or timer) to take advantage of the
special event trigger feature. If Timer5 is running in
Asynchronous Counter mode, the special event trigger
may not work and should not be used.
When Timer5 is configured for asynchronous opera-
tion, it will continue to increment each timer clock (or
prescale multiple of clocks). Executing the SLEEP
instruction will either stop the timer or let the timer con-
tinue, depending on the setting of the Timer5 Sleep
Enable bit, T5SE. If T5SE is set (= 1), the timer contin-
ues to run when the SLEEPinstruction is executed and
the external clock is selected (TMR5CS = 1). If T5SE is
cleared, the timer stops when a SLEEP instruction is
executed, regardless of the state of the GTPCS bit.
14.7 Timer5 Special Event Reset Input
In addition to the special event output, Timer5 has a
Special Event Reset input that may be used with Input
Capture channel 1 (IC1) of the Motion Feedback
module. To use the Special Event Reset, the Capture 1
Control register CAP1CON must be configured for one
of the special event trigger modes (CAP1M3:CAP1M0
= 1110or 1111). The Special Event Reset trigger can
be disabled by setting the RESEN control bit
(T5CON<6>).
To summarize, Timer5 will continue to increment when
a SLEEPinstruction is executed only if all of these bits
are set:
• TMR5ON
• T5SE
• TMR5CS
• T5SYNC
The Special Event Reset resets the Timer5 time base.
This reset occurs in either Continuous-count or Single-
shot modes.
14.8.1
INTERRUPT DETECT IN SLEEP
MODE
14.7.1
WAKE-UP ON IC1 EDGE
When configured as described above, Timer5 will
continue to increment on each rising edge on T5CKI
while in Sleep mode. When a TMR5/PR5 match
occurs, an interrupt is generated which can wake the
part.
The Timer5 Special Event Reset input can act as a
Timer5 wake-up and a start-up pulse. Timer5 must be
in Single-shot mode and disabled (TMR5ON = 0). An
active edge on the CAP1 input pin will set TMR5ON;
the timer is subsequently incremented on the next fol-
lowing clock according to the prescaler and the Timer5
clock settings. A subsequent hardware time-out (such
as TMR5/PR5 match) will clear the TMR5ON bit and
stop the timer.
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TABLE 14-1:
REGISTERS ASSOCIATED WITH TIMER5
Value on all
other
Resets
Value on:
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
IPR3
GIE/GIEH PEIE/GIEL TMR0IE
INT0IE
PTIP
PTIE
PTIF
RBIE
TMR0IF
INT0IF
IC1IP
IC1IE
IC1IF
RBIF
0000 000x 0000 000u
—
—
—
—
—
—
—
—
—
IC3DRIP IC2QEIP
IC3DRIE IC2QEIE
IC3DRIF IC2QEIF
TMR5IP ---1 1111 ---1 1111
TMR5IE ---0 0000 ---0 0000
TMR5IF ---0 0000 ---0 0000
xxxx xxxx uuuu uuuu
PIE3
PIR3
TMR5H
TMR5L
PR5H
Timer5 Register High Byte
TImer5 Register Low Byte
xxxx xxxx uuuu uuuu
Timer5 Period Register High Byte
Timer5 Period Register Low Byte
1111 1111 1111 1111
PR5L
1111 1111 1111 1111
0000 0000 0000 0000
T5CON
CAP1CON
DFLTCON
Legend:
T5SEN
—
RESEN
CAP1REN
FLT4EN
T5MOD
—
T5PS1
—
T5PS0 T5SYNC TMR5CS TMR5ON
CAP1M3 CAP1M2 CAP1M1 CAP1M0 -1-- 0000 -1-0 0000
—
FLT3EN FLT2EN FLT1EN FLTCK2 FLTCK1 FLTCK0 -000 0000 -000 0000
x = unknown, u = unchanged, – = unimplemented.
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NOTES:
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15.0 CAPTURE/COMPARE/PWM
(CCP) MODULES
The CCP (Capture/Compare/PWM) module contains a
16-bit register that can operate as a 16-bit Capture reg-
ister, a 16-bit Compare register or a PWM Master/Slave
Duty Cycle register. Table 15-1 shows the timer
resources required for each of the CCP module modes.
The operation of CCP1 is identical to that of CCP2, with
the exception of the special event trigger. Therefore,
operation of a CCP module is described with respect to
CCP1, except where noted.
REGISTER 15-1: CCPxCON: CCP MODULE CONTROL REGISTER
U-0
—
U-0
—
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
DCxB1
DCxB0
CCPxM3 CCPxM2 CCPxM1 CCPxM0
bit 0
bit 7
bit 7-6 Unimplemented: Read as ‘0’
bit 5-4 DCxB1:DCxB0: PWM Duty Cycle bit1 and bit0
Capture mode:
Unused
Compare mode:
Unused
PWM mode:
These bits are the two LSbs (bit 1 and bit 0) of the 10-bit PWM duty cycle. The upper eight bits
(DCx9:DCx2) of the duty cycle are found in CCPRxL.
bit 3-0 CCPxM3:CCPxM0: CCPx Mode Select bits
0000=Capture/Compare/PWM disabled (resets CCPx module)
0001=Reserved
0010=Compare mode, toggle output on match (CCPxIF bit is set)
0011=Reserved
0100=Capture mode, every falling edge
0101=Capture mode, every rising edge
0110=Capture mode, every 4th rising edge
0111=Capture mode, every 16th rising edge
1000=Compare mode, Initialize CCP pin Low, on compare match force CCP pin High
(CCPxIF bit is set)
1001=Compare mode, Initialize CCP pin High, on compare match force CCP pin Low
(CCPxIF bit is set)
1010=Compare mode, Generate software interrupt-on-compare match (CCPxIF bit is set,
CCP pin is unaffected)
1011=Compare mode, Trigger special event (CCP2IF bit is set)
11xx=PWM mode
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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15.1 CCP1 Module
15.2 CCP2 Module
Capture/Compare/PWM Register
1
(CCPR1) is
Capture/Compare/PWM Register2 (CCPR2) is com-
prised of two 8-bit registers: CCPR2L (low byte) and
CCPR2H (high byte). The CCP2CON register controls
the operation of CCP2. All are readable and writable.
comprised of two 8-bit registers: CCPR1L (low byte)
and CCPR1H (high byte). The CCP1CON register
controls the operation of CCP1. All are readable and
writable.
TABLE 15-1: CCP MODE – TIMER
RESOURCE
CCP Mode
Timer Resource
Capture
Compare
PWM
Timer1
Timer1
Timer2
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15.3.3
SOFTWARE INTERRUPT
15.3 Capture Mode
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep bit
CCP1IE (PIE1<2>) clear to avoid false interrupts and
should clear the flag bit, CCP1IF, following any such
change in operating mode.
In Capture mode, CCPR1H:CCPR1L captures the 16-
bit value of the TMR1 register when an event occurs on
pin RC2/CCP1. An event is defined as one of the
following:
• every falling edge
• every rising edge
15.3.4
CCP PRESCALER
• every 4th rising edge
• every 16th rising edge
There are four prescaler settings, specified by bits
CCP1M3:CCP1M0. Whenever the CCP module is
turned off or the CCP module is not in Capture mode,
the prescaler counter is cleared. This means that any
Reset will clear the prescaler counter.
The event is selected by control bits CCP1M3:CCP1M0
(CCP1CON<3:0>). When a capture is made, the
interrupt request flag bit CCP1IF (PIR1<2>) is set; it
must be cleared in software. If another capture occurs
before the value in register CCPR1 is read, the old
captured value is overwritten by the new captured value.
Switching from one capture prescaler to another may
generate an interrupt. Also, the prescaler counter will
not be cleared, therefore, the first capture may be from
a non-zero prescaler. Example 15-1 shows the recom-
mended method for switching between capture pres-
calers. This example also clears the prescaler counter
and will not generate the “false” interrupt.
15.3.1
CCP PIN CONFIGURATION
In Capture mode, the RC2/CCP1 pin should be
configured as an input by setting the TRISC<2> bit.
Note:
If the RC2/CCP1 is configured as an out-
put, a write to the port can cause a capture
condition.
EXAMPLE 15-1:
CHANGING BETWEEN
CAPTURE PRESCALERS
CLRF
CCP1CON, F
; Turn CCP module off
; Load WREG with the
; new prescaler mode
; value and CCP ON
; Load CCP1CON with
; this value
MOVLW
NEW_CAPT_PS
CCP1CON
15.3.2
TIMER1 MODE SELECTION
Timer 1 must be running in Timer mode or Synchro-
nized Counter mode to be used with the capture fea-
ture. In Asynchronous Counter mode, the capture
operation may not work.
MOVWF
FIGURE 15-1:
CAPTURE MODE OPERATION BLOCK DIAGRAM
Set Flag bit CCP1IF
Prescaler
CCPR1H
CCPR1L
÷ 1, 4, 16
TMR1
Enable
CCP1 pin
and
TMR1H
TMR1L
Edge Detect
CCP1CON<3:0>
Q’s
Set Flag bit CCP2IF
Prescaler
÷ 1, 4, 16
CCPR2H
CCPR2L
TMR1L
TMR1
Enable
CCP2 pin
and
TMR1H
Edge Detect
CCP2CON<3:0>
Q’s
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15.4.2
TIMER1 MODE SELECTION
15.4 Compare Mode
Timer1 must be running in Timer mode or Synchro-
nized Counter mode if the CCP module is using the
compare feature. In Asynchronous Counter mode, the
compare operation may not work.
In Compare mode, the 16-bit CCPR1 (CCPR2) register
value is constantly compared against the TMR1
register pair value. When a match occurs, the RC2/
CCP1 (RC1/CCP2) pin:
• Is driven High
15.4.3
SOFTWARE INTERRUPT MODE
• Is driven Low
When generate software interrupt is chosen, the CCP1
pin is not affected. Only a CCP interrupt is generated (if
enabled).
• Toggles output (High-to-Low or Low-to-High)
• Remains unchanged (interrupt only)
The action on the pin is based on the value of control
bits CCP1M3:CCP1M0 (CCP2M3:CCP2M0). At the
same time, interrupt flag bit CCP1IF (CCP2IF) is set.
15.4.4
SPECIAL EVENT TRIGGER
In this mode, an internal hardware trigger is generated,
which may be used to initiate an action.
15.4.1
CCP PIN CONFIGURATION
The special event trigger output of CCP1 resets the
TMR1 register pair. This allows the CCPR1 register to
effectively be a 16-bit programmable period register for
Timer1.
The user must configure the CCPx pin as an output by
clearing the appropriate TRISC bit.
Note:
Clearing the CCP1CON register will force
the RC2/CCP1 compare output latch to
the default low level. This is not the
PORTC I/O data latch.
The special trigger output of CCP2 resets the TMR1
register pair. Additionally, the CCP2 special event
trigger will start an A/D conversion if the A/D module is
enabled.
Note:
The special event trigger from the CCP2
module will not set the Timer1 interrupt
flag bit.
FIGURE 15-2:
COMPARE MODE OPERATION BLOCK DIAGRAM
Special Event Trigger will:
Reset Timer1, but not set Timer1 interrupt flag bit,
and set bit GO/DONE (ADCON0<2>), which starts an A/D conversion (CCP2 only)
Special Event Trigger
Set Flag bit CCP1IF
CCPR1H CCPR1L
Comparator
Q
S
R
Output
Logic
Match
RC2/CCP1 pin
TRISC<2>
Output Enable
CCP1CON<3:0>
Mode Select
TMR1H TMR1L
Special Event Trigger
Set Flag bit CCP2IF
Q
S
R
Output
Logic
Comparator
Match
RC1/CCP2 pin
TRISC<1>
Output Enable
CCPR2H CCPR2L
CCP2CON<3:0>
Mode Select
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TABLE 15-2: REGISTERS ASSOCIATED WITH CAPTURE, COMPARE AND TIMER1
Value on
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
all other
Resets
INTCON
PIR1
GIE/GIEH PEIE/GIEL TMR0IE
INT0IE
TXIF
RBIE
SSPIF
SSPIE
SSPIP
TMR0IF
INT0IF
RBIF
0000 000x 0000 000u
—
—
—
ADIF
ADIE
ADIP
RCIF
RCIE
RCIP
CCP1IF TMR2IF TMR1IF -000 0000 -000 0000
CCP1IE TMR2IE TMR1IE -000 0000 -000 0000
CCP1IP TMR2IP TMR1IP -111 1111 -111 1111
1111 1111 1111 1111
PIE1
TXIE
TXIP
IPR1
TRISC
TMR1L
TMR1H
T1CON
CCPR1L
PORTC Data Direction Register
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
RD16
T1RUN T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0000 0000 uuuu uuuu
Capture/Compare/PWM Register1 (LSB)
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
CCPR1H Capture/Compare/PWM Register1 (MSB)
CCP1CON
CCPR2L
—
—
DC1B1
DC1B0
CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
xxxx xxxx uuuu uuuu
Capture/Compare/PWM Register2 (LSB)
CCPR2H Capture/Compare/PWM Register2 (MSB)
xxxx xxxx uuuu uuuu
CCP2CON
PIR2
—
—
DC2B1
—
DC2B0
EEIF
CCP2M3 CCP2M2 CCP2M1 CCP2M0 --00 0000 --00 0000
OSCFIF
OSCFIE
OSCFIP
CMIF
CMIE
CMIP
BCLIF
BCLIE
BCLIP
LVDIF
LVDIE
LVDIP
TMR3IF CCP2IF 00-0 0000 00-0 0000
TMR3IE CCP2IE 00-0 0000 00-0 0000
TMR3IP CCP2IP 11-1 1111 11-1 1111
PIE2
—
EEIE
EEIP
IPR2
—
Legend: x= unknown, u= unchanged, — = unimplemented, read as ‘0’. Shaded cells are not used by Capture and Timer1.
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15.5.1
PWM PERIOD
15.5 PWM Mode
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following equation.
In Pulse Width Modulation (PWM) mode, the CCP1 pin
produces up to a 10-bit resolution PWM output. Since
the CCP1 pin is multiplexed with the PORTC data latch,
the TRISC<2> bit must be cleared to make the CCP1
pin an output.
EQUATION 15-1:
PWM period = [(PR2) + 1] • 4 • TOSC •
(TMR2 prescale value)
Note:
Clearing the CCP1CON register will force
the CCP1 PWM output latch to the default
low level. This is not the PORTC I/O data
latch.
PWM frequency is defined as 1/[PWM period]. When
TMR2 is equal to PR2, the following three events occur
on the next increment cycle:
Figure 15-3 shows a simplified block diagram of the
CCP module in PWM mode.
• TMR2 is cleared
For a step-by-step procedure on how to set up the CCP
module for PWM operation, see Section 15.5.3
“Setup for PWM Operation”.
• The CCP1 pin is set (if PWM duty cycle = 0%, the
CCP1 pin will not be set)
• The PWM duty cycle is copied from CCPR1L into
CCPR1H
FIGURE 15-3:
SIMPLIFIED PWM BLOCK
DIAGRAM
Note: The Timer2 postscaler (see Section 13.0
“Timer2 Module”) is not used in the deter-
mination of the PWM frequency. The
postscaler could be used to have a servo
update rate at a different frequency than
the PWM output.
CCP1CON<5:4>
Duty Cycle Registers
CCPR1L
15.5.2
PWM DUTY CYCLE
CCPR1H (Slave)
Comparator
The PWM duty cycle is specified by writing to the
CCPR1L register and to the CCP1CON<5:4> bits. Up
to 10-bit resolution is available. The CCPR1L contains
the eight MSbs and the CCP1CON<5:4> contains the
two LSbs. This 10-bit value is represented by
CCPR1L:CCP1CON<5:4>. The PWM duty cycle is
calculated by the following equation.
R
S
Q
RC2/CCP1
(Note 1)
TMR2
TRISC<2>
Comparator
PR2
Clear Timer,
CCP1 pin and
latch D.C.
EQUATION 15-2:
PWM duty cycle = (CCPR1L:CCP1CON<5:4>) •
Tosc • (TMR2 prescale value)
Note: 8-bit timer is concatenated with 2-bit internal Q clock or
2 bits of the prescaler to create 10-bit time base.
CCPR1L and CCP1CON<5:4> can be written to at any
time, but the duty cycle value is not copied into
CCPR1H until a match between PR2 and TMR2 occurs
(i.e., the period is complete). In PWM mode, CCPR1H
is a read-only register.
A PWM output (Figure 15-4) has a time base
(period) and a time that the output is high (duty
cycle). The frequency of the PWM is the inverse of
the period (1/period).
FIGURE 15-4:
PWM OUTPUT
Period
Duty Cycle
TMR2 = PR2
TMR2 = Duty Cycle
TMR2 = PR2
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The CCPR1H register and a 2-bit internal latch are
used to double buffer the PWM duty cycle. This double
buffering is essential for glitchless PWM operation.
When the CCPR1H and 2-bit latch match TMR2,
concatenated with an internal 2-bit Q clock or two bits
of the TMR2 prescaler, the CCP1 pin is cleared. The
maximum PWM resolution (bits) for a given PWM
frequency is given by the following equation.
15.5.3
SETUP FOR PWM OPERATION
The following steps should be taken when configuring
the CCP module for PWM operation:
1. Set the PWM period by writing to the PR2 register.
2. Set the PWM duty cycle by writing to the CCPR1L
register and CCP1CON<5:4> bits.
3. Make the CCP1 pin an output by clearing the
TRISC<2> bit.
EQUATION 15-3:
4. Set the TMR2 prescale value and enable Timer2
by writing to T2CON.
FOSC
FPWM
log
5. Configure the CCP1 module for PWM operation.
PWM Resolution (max) =
bits
log(2)
Note:
If the PWM duty cycle value is longer than
the PWM period, the CCP1 pin will not be
cleared.
TABLE 15-3: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
PWM Frequency
2.44 kHz
9.77 kHz
39.06 kHz 156.25 kHz 312.50 kHz 416.67 kHz
Timer Prescaler (1, 4, 16)
PR2 Value
16
FFh
10
4
1
1
3Fh
8
1
1Fh
7
1
FFh
10
FFh
10
17h
6.58
Maximum Resolution (bits)
TABLE 15-4: REGISTERS ASSOCIATED WITH PWM AND TIMER2
Value on
POR,
BOR
Value on
all other
Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE/GIEH PEIE/GIEL TMR0IE
INT0IE
TXIF
RBIE
SSPIF
SSPIE
SSPIP
TMR0IF
CCP1IF
INT0IF
RBIF
0000 000x 0000 000u
—
—
—
ADIF
ADIE
ADIP
RCIF
RCIE
RCIP
TMR2IF
TMR1IF -000 0000 -000 0000
TMR1IE -000 0000 -000 0000
TMR1IP -111 1111 -111 1111
1111 1111 1111 1111
PIE1
TXIE
TXIP
CCP1IE TMR2IE
CCP1IP TMR2IP
IPR1
TRISC
TMR2
PR2
PORTC Data Direction Register
Timer2 Module Register
0000 0000 0000 0000
Timer2 Module Period Register
1111 1111 1111 1111
T2CON
CCPR1L
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
Capture/Compare/PWM Register1 (LSB)
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
CCPR1H Capture/Compare/PWM Register1 (MSB)
CCP1CON
CCPR2L
—
—
DC1B1
DC1B0
CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
xxxx xxxx uuuu uuuu
Capture/Compare/PWM Register2 (LSB)
CCPR2H Capture/Compare/PWM Register2 (MSB)
CCP2CON DC2B1 DC2B0
xxxx xxxx uuuu uuuu
—
—
CCP2M3 CCP2M2 CCP2M1 CCP2M0 --00 0000 --00 0000
Legend: x= unknown, u= unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by PWM and Timer2.
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NOTES:
DS39616B-page 158
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Many of the features for the IC and QEI submodules
16.0 MOTION FEEDBACK MODULE
are fully programmable, creating a flexible peripheral
structure that can accommodate a wide range of
in-system uses. An overview of the available features
is presented in Table 16-1. A simplified block diagram
of the entire Motion Feedback module is shown in
Figure 16-1.
The Motion Feedback module is a special-purpose
peripheral designed for motion feedback applications.
Together with the Power Control PWM module (see
Section 17.0 “Power Control PWM Module”), it pro-
vides a variety of control solutions for a wide range of
electric motors.
Note:
Because the same input pins are common
to the IC and QEI submodules, only one of
these two submodules may be used at any
given time. If both modules are on, the QEI
submodule will take precedence.
The module actually consists of two hardware
sub-modules:
• Input Capture module (IC)
•
Quadrature Encoder Interface (QEI).
Together with Timer5 (see Section 14.0 “Timer5 Mod-
ule”), these modules provide a number of options for
motion and control applications.
TABLE 16-1: SUMMARY OF MOTION FEEDBACK MODULE FEATURES
Submodule
Mode(s)
Features
Timer
Function
IC (3x)
• Synchronous
• Input Capture
• Flexible input capture modes
• Available prescaler
• Selectable time base reset
• Special event trigger for ADC
sampling/conversion or
TMR5 • 3x Input Capture (edge
capture, pulse width, period
measurement, capture on
change)
• Special event triggers the A/D
conversion on the CAP1 input
optional TMR5 Reset feature
(CAP1 only)
• Wake-up from Sleep function
• Selectable interrupt frequency
• Optional noise filter
QEI
QEI
• Detect position
16-bit • Position measurement
position • Direction of rotation status
counter
• Detect direction of rotation
• Large bandwidth (Fcy/16)
• Optional noise filter
Velocity
measurement
• 2x and 4x update modes
• Velocity event postscaler
• Counter overflow flag for low
rotation speed
TMR5 • Precise velocity measurement
• Direction of rotation status
• Utilizes Input Capture 1 logic
(IC1)
• High and low velocity support
2003 Microchip Technology Inc.
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FIGURE 16-1:
MOTION FEEDBACK MODULE BLOCK DIAGRAM
TMR5IF
Special Reset Trigger
Timer Reset
TMR5
Reset
Control
Special Event output
Timer5
TMR5<15:0>
8
Filter
TCY
T5CKI
3x Input Capture Logic
TMR5<15:0>
IC3IF
Filter
8
8
IC3
CAP3/QEB
IC2IF
Filter
Filter
IC2
IC1
CAP2/QEA
IC1IF
Special Reset Trigger
8
CAP1/INDX
Clock
Divider
8
Postscaler
TCY
QEB
Velocity Event
Timer reset
8
Direction
Clock
QEA
Position Counter
QEIF
QEI
Control
CHGIF
Logic
INDX
8
QEI Logic
CHGIF
IC3IF
IC3DRIF
QEI
Mode
8
Decoder
QEIF
IC2IF
IC2QEIF
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Input channel (IC1) includes a special event trigger
that can be configured for use in Velocity Measure-
ment mode. Its block diagram is shown in Figure 16-2.
IC2 and IC3 are similar, but lack the special event trig-
ger features or additional velocity-measurement logic.
16.1 Input Capture
The Input Capture (IC) submodule implements the
following features:
• Three channels of independent input capture
(16-bits/channel) on the CAP1, CAP2 and CAP3
pins
A
representative block diagram is shown in
Figure 16-3. Please note that the time base is Timer5.
• Edge-trigger, period or pulse width measurement
operating modes for each channel
• Programmable prescaler on every input capture
channel
• Special event trigger output (IC1 only)
• Selectable noise filters on each capture input
FIGURE 16-2:
INPUT CAPTURE BLOCK DIAGRAM FOR IC1
CAP1 Pin
and
Mode
Select
Clock
Prescaler
1, 4, 16
Noise
Filter
CAP1BUF/VELR(1)
3
4
FLTCK<2:0>
Q clocks
CAP1M<3:0>
IC1IF
IC1_TR
Reset
TMR5
Special
Reset
Event
Reset
Control
Clock/
Timer5 Logic
Reset/
Interrupt
Decode
Logic
1
CAP1BUF_clk
First Event
Reset
MUX
0
Timer
Reset
Control
Timer5 Reset
velcap(2)
VELM
Q Clocks
CAP1M<3:0>
Note 1: CAP1BUF register is reconfigured as VELR register when QEI mode is active.
2: QEI generated velocity pulses, vel_out, are downsampled to produce this velocity capture signal.
2003 Microchip Technology Inc.
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FIGURE 16-3:
INPUT CAPTURE BLOCK DIAGRAM FOR IC2 AND IC3
Capture
Clock
CAPxBUF(1,2,3)
CAP2/CAP3 Pin
and
Prescaler
Noise
Filter
Mode
1, 4, 16
Select
TMR5
Enable
3
Q’s
4
TMR5
CAPxM<3:0>(1)
FLTCK<2:0>
ICxIF(1)
Capture Clock/
Reset/
CAPxBUF_clk(1)
Interrupt
Decode
Logic
TMR5 Reset
Timer
Reset
Control
Reset
Q clocks CAPxM<3:0>(1)
CAPxREN(2)
Note 1: IC2 and IC3 are denoted as x=2 and 3.
2: CAP2BUF is enabled as POSCNT when QEI mode is active.
3: CAP3BUF is enabled as MAXCNT when QEI mode is active.
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The three Input Capture channels are controlled
through the Input Capture Control Registers
CAP1CON, CAP2CON, and CAP3CON. Each channel
is configured independently with its dedicated register.
The implementation of the registers is identical, except
for the Special Event trigger (see Section 16.1.8 “Spe-
cial Event Trigger (CAP1 Only)”). The typical Capture
Control register is shown in Register 16-1.
REGISTER 16-1: CAPxCON: INPUT CAPTURE CONTROL REGISTER
U-0
—
R/W-0
U-0
—
R/W-0
—
R/W-0
R/W-0
R/W-0
R/W-0
CAPxREN
CAPxM3 CAPxM2 CAPxM1 CAPxM0
bit 0
bit 7
bit 7
bit 6
Unimplemented: Read as ‘0’
CAPxREN: Time Base Reset Enable bit
1= Enabled
0= Disable selected time base Reset on capture.
bit 5
Unimplemented: Read as ‘0’
Unimplemented: Read as ‘0’
bit 4
bit 3-0
CAPxM3:CAPxM0: Input Capture 1 (ICx) Mode Select bits
1111= Special Event Trigger mode. The trigger occurs on every rising edge on CAP1 input(1)
1110= Special Event Trigger mode. The trigger occurs on every falling edge on CAP1 input(1)
1101= Unused
1100= Unused
1011= Unused
1010= Unused
1001= Unused
1000= Capture on every CAPx input state change
0111= Pulse Width Measurement mode, every rising to falling edge
0110= Pulse Width Measurement mode, every falling to rising edge
0101= Frequency Measurement mode, every rising edge
0100= Capture mode, every 16th rising edge
0011= Capture mode, every 4th rising edge
0010= Capture mode, every rising edge
0001= Capture mode, every falling edge
0000= Input Capture 1 (ICx) off
Note 1: Special Event Trigger is only available on CAP1. For CAP2 and CAP3, this config-
uration is unused.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
When in Counter mode, the counter must be
configured as the synchronous counter only
(TMR5SYNC = 0). When configured in Asynchronous
mode, the IC module will not work properly.
Note:
Throughout this section, references to
registers and bit names that may be asso-
ciated with a specific capture channel will
be referred to generically by the use of the
term ‘x’ in place of the channel number.
For example, ‘CAPxREN’ may refer to the
Capture Reset Enable bit in CAP1CON,
CAP2CON or CAP3CON.
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16.1.1
EDGE CAPTURE MODE
Note 1: Input capture prescalers are reset
In this mode, the value of the time base is captured
either on every rising edge, every falling edge, every
4th rising edge, or every 16th rising edge. The edge
present on the input capture pin (CAP1, CAP2 or
CAP3) is sampled by the synchronizing latch. The
signal is used to load the input capture buffer (ICxBUF
register) on the following Q1 clock (see Figure 16-4).
Consequently, Timer5 is either reset to ‘0’ (Q1
immediately following the capture event) or left free
running, depending on the setting of Capture Reset
Enable, CAPxREN, in the CAPxCON register.
(cleared) when the Input Capture module
is disabled (CAPxM = 0000).
2: When the Input Capture mode is changed
without first disabling the module and
entering the new Input Capture mode, a
false interrupt (or special event trigger on
IC1) may be generated. The user should
either (1) disable the Input Capture before
entering another mode or (2) disable IC
interrupts to avoid false interrupts during
IC mode changes.
Note:
On the first capture edge following the
setting of the Input Capture mode (i.e.,
MOVWF CAP1CON), Timer5 contents are
always captured into the corresponding
input capture buffer (i.e., CAPxBUF).
Timer5 can optionally be reset; however,
this is dependent on the setting of the
Capture Reset Enable bit (CAPxREN),
see Figure 16-4.
3: During IC mode changes, the prescaler
count will not be cleared, therefore the
first capture in the new IC mode may be
from the non-zero prescaler.
FIGURE 16-4:
EDGE CAPTURE MODE TIMING
Q1Q2 Q3 Q4 Q1
Q4Q1Q2Q3 Q4 Q1Q2Q3Q4 Q1Q2 Q3 Q4 Q1Q2Q3Q4Q1Q2Q3Q4 Q1Q2 Q3 Q4 Q1Q2Q3Q4 Q1Q2Q3Q4
Q2Q3
OSC
(1)
0012
0013
0014
0015
0000
0016
0001
0002
0000
0001
0002
TMR5
(2)
CAP1 pin
ABCD
0003
0002
(3)
CAP1BUF
Note 5
(4)
TMR5 reset
Instruction
Execution
MOVWF CAP1CON
BCF CAP1CON, CAP1REN
Note 1: TMR5 is a synchronous time base input to the Input Capture, prescaler = 1:1. It increments on Q1 rising edge.
2: IC1 is configured in Edge Capture mode (CAP1M3:CAP1M0 = 0010) with the time base reset upon edge capture
(CAP1REN = 1) and no noise filter.
3: TMR5 value is latched by CAP1BUF on TCY. In the event that a write to TMR5 coincides with an input capture event,
the write will always take precedence. All input capture buffers, CAP1BUF, CAP2BUF and CAP3BUF, are updated with
the incremented value of the time base on the next TCY clock edge when the capture event takes place (see Note 4
when Reset occurs).
4: TMR5 Reset is normally an asynchronous reset signal to TMR5. When used with the input capture, it is active immedi-
ately after the time base value is captured.
5: TMR5 Reset pulse is disabled by clearing CAP1REN bit (e.g, BCF CAP1CON, CAP1REN).
DS39616B-page 164
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of the CAPx input pin (CAPxM3:CAPxM0 = 0110), or
on the rising to falling edge (CAPxM3:CAPxM0 =
0111).
16.1.2
PERIOD MEASUREMENT MODE
The Period Measurement mode is selected by setting
CAPxM3:CAPxM0 = 0101. In this mode, the value of
Timer5 is latched into the CAPxBUF register on the ris-
ing edge of the input capture trigger and Timer5 is sub-
sequently reset to 0000h (optional by setting
CAPxREN = 1) on the next TCY (see capture and reset
relationship in Figure 16-4).
Timer5 is always reset on the edge when the
measurement is first initiated. For example, when the
measurement is based on the falling to rising edge,
Timer5 is first reset on the falling edge and the timer
value is captured on the rising edge thereafter. Upon
entry into the Pulse Width Measurement mode, the
very first edge detected on the CAPx pin is always
captured. The TMR5 value is reset on the first active
edge (see Figure 16-5).
16.1.3
PULSE WIDTH MEASUREMENT
MODE
The Pulse Width Measurement mode can be config-
ured for two different edge sequences, such that the
pulse width is based on either the falling to rising edge
FIGURE 16-5:
PULSE WIDTH MEASUREMENT MODE TIMING
Q1Q2Q3 Q4
0001
Q1Q2Q3Q4 Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 Q1Q2Q3Q4
Q1Q2Q3Q4
0002
(1)
0012
0013
0014
0015
0000
0001
0002
0001
0000
TMR5
(2)
CAP1 pin
0015
0002
(3)
CAP1BUF
(4,5)
TMR5 reset
MOVWF CAP1CON
(2)
Instruction
Execution
Note 1: TMR5 is a synchronous time base input to the Input Capture, prescaler = 1:1. It increments on every Q1 rising edge.
2: IC1 is configured in Pulse Width Measurement mode (CAP1M3:CAP1M0 = 0111, rising to falling pulse width measure-
ment). No noise filter on CAP1 input is used. MOVWFinstruction loads CAP1CON when W = 0111.
3: TMR5 value is latched by CAP1BUF on TCY rising edge. In the event that a write to TMR5 coincides with an input cap-
ture event, the write will always take precedence. All input capture buffers, CAP1BUF, CAP2BUF and CAP3BUF, are
updated with the incremented value of the time base on the next TCY clock edge when the capture event takes place
(see Note 4 when Reset occurs).
4: TMR5 Reset is normally an asynchronous Reset signal to TMR5. When used in Pulse Width Measurement mode, it is
always present on the edge that first initiates the pulse width measurement (i.e., when configured in the rising to falling
Pulse Width Measurement mode, it is active on each rising edge detected. In the falling to rising Pulse Width Measure-
ment mode, it is active on each falling edge detected.
5: TMR5 Reset pulse is activated on the capture edge. CAP1REN bit has no bearing in this mode.
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16.1.3.1
Pulse Width Measurement Timing
16.1.4
INPUT CAPTURE ON STATE
CHANGE
Pulse width measurement accuracy can be only
ensured when the pulse width high and low present on
CAPx input exceeds one TCY clock cycle. The
limitations depend on the mode selected:
When CAPxM3:CAPxM0 = 1000, the value is captured
on every signal change on the CAPx input. If all three
capture channels are configured in this mode, the
three-input-capture can be used as the Hall-effect
sensor state transition detector. The value of Timer5
can be captured, Timer5 reset and the interrupt
generated. Any change on CAP1, CAP2 or CAP3 is
detected and the associated time base count is
captured.
• When CAPxM3:CAPxM0 = 0110(rising-to-falling
edge delay), the CAPx input high pulse width
(TccH) must exceed TCY + 10 ns.
• When CAPxM3:CAPxM0 = 0111(falling-to-rising
edge delay), the CAPx input low pulse width
(TccL) must exceed TCY + 10 ns.
For position and velocity measurement in this mode,
the timer can be optionally reset (see Section 16.1.6
“Timer5 Reset” for Reset options).
Note 1: The Period Measurement mode will
produce valid results upon sampling of
the second rising edge of the input
capture. CAPxBUF values latched during
the first active edge after initialization are
invalid.
2: The Pulse Width Measurement mode will
latch the value of the timer upon sampling
of the first input signal edge by the input
capture.
FIGURE 16-6:
INPUT CAPTURE ON STATE CHANGE (HALL-EFFECT SENSOR MODE)
1
0
1
0
1
1
0
1
0
1
0
0
CAP1
CAP2
CAP3
1
0
0
0
1
1
0FFFh
0000h
(1)
Time Base
(2)
CAP1BUF
(2)
CAP2BUF
CAP3BUF
(2)
(1)
Time Base Reset
Note 1: TMR5 can be selected as the time base for input capture. Time base can be optionally reset when the capture reset
enabled bit is set (CAPXREN = 1).
2: Detailed CAPxBUF event timing (all modes reflect same capture and Reset timing) is shown in Figure 16-4.There are
six commutation BLDC hall-effect sensor states shown. The other two remaining states (i.e., 000h and 111h) are
invalid in the normal operation. They are still to be decoded by the CPU firmware in BLDC motor application.
DS39616B-page 166
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16.1.5
ENTERING INPUT CAPTURE MODE
AND CAPTURE TIMING
16.1.6
TIMER5 RESET
Every Input Capture trigger can optionally reset
(TMR5). Capture Reset Enable bit, CAPxREN, gates
the automatic Reset of the time base of the capture
event with this enable Reset signal. All capture events
reset the selected timer when CAPxREN is set. Resets
are disabled when CAPxREN is cleared (see
Figure 16-4, Figure 16-5 and Figure 16-6).
The following is a summary of functional operation
upon entering any of the Input Capture modes:
1. After the module is configured for one of the
capture modes by setting the Mode Select bits
(CAPxM3:CAPxM0), the first detected edge
captures Timer5 value and stores it in the CAPx-
BUF register. The timer is then reset (depending
on the setting of CAPxREN bit) and starts to
increment according to its settings, see
Figure 16-4, Figure 16-5 and Figure 16-6.
Note:
The CAPxREN bit has no effect in Pulse
Width Measurement mode.
16.1.7
IC INTERRUPTS
2. On all edges, the capture logic performs the fol-
lowing:
There are four operating modes for which the IC
module can generate an interrupt and set one of the
Interrupt Capture flag bits (IC1IF, IC2QEIF or
IC3DRIF). The interrupt flag that is set depends on the
channel in which the event occurs. The modes are:
a) Input Capture mode is decoded and the
active edge is identified
b) The CAPxREN bit is checked to determine
whether Timer5 is reset or not.
• Edge capture (CAPxM3:CAPxM0 = 0001, 0010,
0011or 0100)
c) On every active edge, the Timer5 value is
recorded in the input capture buffer (CAPx-
BUF).
• Period measurement event
(CAPxM3:CAPxM0 = 0101)
d) Reset Timer5 after capturing the value of
the timer when CAPxREN bit is enabled.
Timer5 is reset on every active capture
edge in this case.
• Pulse width measurement event
(CAPxM3:CAPxM0 = 0110or 0111)
• State change event (CAPxM3:CAPxM0 = 1000)
Note:
The special event trigger is generated only
in the Special Event Trigger mode on
CAP1 input (CAP1M2:CAP1M0> = 1110
and 1111). IC1IF interrupt is not set in this
mode.
e) On all continuing capture edge events
repeat steps 1 through 4 until the Opera-
tional mode is terminated either by user
firmware, POR or BOR.
f) The timer value is not affected when switch-
ing into and out of various input capture
modes.
The timing of interrupt and special trigger events is
shown in Figure 16-7. Any active edge is detected on
the rising edge of Q2 and propagated on the rising
edge of Q4 rising edge. If an active edge happens to
occur any later than this (on the falling edge of Q2, for
example), then it will be recognized on the next Q2
rising edge.
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FIGURE 16-7:
CAPXIF INTERRUPTS AND IC1 SPECIAL EVENT TRIGGER
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
OSC
CAP1 pin
IC1IF
TMR5 Reset
TMR5
0001
XXXX
0000
(1)
TMR5ON
Note 1: Timer5 is only reset and enabled (assuming: TMR5ON = 0and TMR5MOD = 1) when the Special Event Reset Trigger
is enabled for the Timer5 Reset input. TMR5ON bit is asserted and Timer5 is reset on the Q1 rising edge following the
event capture. With the Special Event Reset Trigger disabled, Timer5 cannot be reset by the Special Event Reset
Trigger on CAP1 input. In order for the Special Event Reset Trigger to work as the Reset trigger to Timer5, IC1 must be
configured in the Special Event Trigger mode (CAP1M<3:0> = 1110or 1111).
16.1.8
SPECIAL EVENT TRIGGER (CAP1
ONLY)
16.1.10 OTHER OPERATING MODES
Although the IC and QEI submodules are mutually
exclusive, the IC can be reconfigured to work with the
QEI module to perform specific functions. In effect, the
QEI “borrows” hardware from the IC to perform these
operations.
The Special Event Trigger mode of IC1
(CAP1M3:CAP1M0 = 1110 or 1111) enables the
Special Event Trigger signal. The trigger signal can be
used as the Special Event Reset input to TMR5,
resetting the timer when the specific event happens on
IC1. The events are summarized in Table 16-2.
For velocity measurement, the QEI uses dedicated
hardware in channel IC1. The CAP1BUF registers are
remapped, becoming the VREG registers. Its operation
and use are described in Section 16.2.6 “Velocity
Measurement”.
TABLE 16-2: SPECIAL EVENT TRIGGER
CAP1M3:
Description
CAP1M0
While in QEI mode, the CAP2BUF and CAP3BUF reg-
isters of channel IC2 and IC3 are used for position
determination. They are remapped as the POSCNT
and MAXCNT buffer registers, respectively.
1110
The trigger occurs on every falling
edge on CAP1 input
1111
The trigger occurs on every rising
edge on CAP1 input
16.1.9
OPERATING MODES SUMMARY
Table 16-3 shows a summary of the input capture con-
figuration when used in conjunction with TMR5 timer
resource.
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TABLE 16-3: INPUT CAPTURE TIME BASE RESET SUMMARY
Reset Timer
on Capture
Pin
CAPxM
Mode
Timer
Description
CAP1 0001-0100 Edge Capture
TMR5
optional(1)
Simple edge Capture mode (includes a
selectable prescaler)
0101
Period Measurement
TMR5
TMR5
optional(1)
always
Captures Timer5 on period boundaries
Captures Timer5 on pulse boundaries
0110-0111 Pulse Width
Measurement
1000
Input Capture on State
Change
TMR5
TMR5
optional(1)
optional(2)
Captures Timer5 on state change
1110-1111 Special Event Trigger
Used as a special event trigger to be used
with the Timer5 or other peripheral
modules
(rising or falling edge)
CAP2 0001-0100 Edge Capture
TMR5
optional(1)
Simple edge Capture mode (includes a
selectable prescaler
0101
Period Measurement
TMR5
TMR5
optional(1)
always
Captures Timer5 on period boundaries
Captures Timer5 on pulse boundaries
0110-0111 Pulse Width
Measurement
1000
Input Capture on State
Change
CAP3 0001-0100 Edge Capture
TMR5
TMR5
optional(1)
optional(1)
Captures Timer5 on state change
Simple edge Capture mode (includes a
selectable prescaler
0101
Period Measurement
TMR5
TMR5
optional(1)
always
Captures Timer5 on period boundaries
Captures Timer5 on pulse boundaries
0110-0111 Pulse Width
Measurement
1000
Input Capture on State
Change
Note 1: Timer5 may be reset on capture events only when CAPxRE = 1.
2: Trigger mode will not reset Timer5 unless RESEN = 0in the T5CON register.
TMR5
optional(1)
Captures Timer5 on state change
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The QEI control logic detects the leading edge on the
16.2 Quadrature Encoder Interface
QEA or QEB phase input pins, and generates the count
pulse which is sent to the position counter logic. It also
samples the index input signal (INDX), and generates
the direction of rotation signal (up/down) and the veloc-
ity event signals.
The Quadrature Encoder Interface (QEI) decodes
speed and motion sensor information. It can be used in
any application that uses a quadrature encoder for
feedback. The interface implements these features:
• Three QEI inputs: two phase signals (QEA and
QEB) and one index signal (INDX)
The position counter acts as an integrator for tracking
distance traveled. The QEA and QEB input edges
serve as the stimulus to create the input clock which
advances the Position Counter Register (POSCNT).
The register is incremented on either the QEA input
edge, or the QEA and QEB input edges, depending on
the operating mode. It is reset either by a rollover on
match to the Period Register, MAXCNT, or on the exter-
nal index pulse input signal (INDX). An interrupt is gen-
erated on a reset of POSCNT if the position counter
interrupt is enabled.
• Direction of movement detection with a direction
change interrupt (IC3DRIF)
• 16-bit up/down position counter
• Standard and high-precision position tracking
modes
• Two position update modes (x2 and x4)
• Velocity measurement with a programmable
postscaler for high-speed velocity measurement
• Position counter interrupt (IC2QEIF in the PIR3
register)
The velocity postscaler down-samples the velocity
pulses used to increment the velocity counter by a
specified ratio. It essentially divides down the number
of velocity pulses to one output per so many input, pre-
serving the pulse width in the process.
• Velocity control interrupt (IC1IF in the PIR3
register)
The QEI sub-module has three main components: the
QEI control logic block, the position counter and
velocity postscaler.
A simplified block-diagram of the QEI module is shown
in Figure 16-8.
FIGURE 16-8:
QEI BLOCK DIAGRAM
QEI Module
Direction change
Timer reset
Set CHGIF
Reset Timer5
Velocity Capture
8
Velocity Event
Postscaler
Set UP/DOWN
QEB
Filter
Direction
Clock
8
POSCNT/CAP2BUF
Comparator
QEA
Reset on match
CAP3/QEB
CAP2/QEA
INDX
Filter
Filter
Set IC2QEIF
8
MAXCNT/CAP3BUF
QEI
Control
Logic
Position Counter
CAP1/INDX
8
8
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The operation of the QEI is controlled by the QEICON
configuration register. See Register 16-2.
16.2.1
QEI CONFIGURATION
The QEI module shares its input pins with the Input
Capture module. The inputs are mutually exclusive;
only the IC module or the QEI module (but not both)
can be enabled at one time. Also, because the IC and
QEI are multiplexed to the same input pins, the
programmable noise filters can be dedicated to one
module only.
Note:
In the event that both QEI and IC are
enabled, QEI will take precedence and IC
will remain disabled.
REGISTER 16-2: QEICON: QUADRATURE ENCODER INTERFACE CONTROL REGISTER
R/W-0
VELM
R/W-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
ERROR UP/DOWN QEIM2
QEIM1
QEIM0
PDEC1
PDEC0
bit 7
bit 0
bit 7
bit 6
bit 5
VELM: Velocity Mode bit
1= Velocity mode disabled
0= Velocity mode enabled
ERROR: QEI error bit(1)
1= Position counter(4) overflow or underflow
0= No overflow or underflow
UP/DOWN: Direction of Rotation Status bit(1)
1= Forward
0= Reverse
bit 4-2 QEIM2:QEIM0: QEI Mode bits(2,3)
111=Unused
110=QEI enabled in 4x Update mode; position counter reset on period match
(POSCNT = MAXCNT)
101=QEI enabled in 4x Update mode; INDX resets the position counter
100=Unused
010=QEI enabled in 2x Update mode; position counter reset on period match
(POSCNT = MAXCNT)
001=QEI enabled in 2x Update mode; INDX resets the position counter
000=QEI off
bit 1-0 PDEC1:PDEC0: Velocity Pulse Reduction Ratio bit
11=1:64
10=1:16
01=1:4
00=1:1
Note 1: QEI must be enabled and in Index mode.
2: QEI mode select must be cleared (= 000) to enable CAP1, CAP2 or CAP3 inputs. If QEI and
IC modules are both enabled, QEI will take precedence.
3: Enabling one of the QEI operating modes remaps the IC buffer registers CAP1BUFH,
CAP1BUFL, CAP2BUFH, CAP2BUFL, CAP3BUFH and CAP3BUFL as the VREGH,
VREGL, POSCNTH, POSCNTL, MAXCNTH, and MAXCNTL registers (respectively) for the
QEI.
4: ERROR bit must be cleared in software.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
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16.2.2
QEI MODES
16.2.3
QEI OPERATION
Position measurement resolution depends on how
often the Position Counter register, POSCNT, is
incremented. There are two QEI update modes to
measure the rotor’s position: QEI x2 and QEI x4.
The Position Counter register pair (POSCNTH:
POSCNTL) acts as an integrator, whose value is pro-
portional to the position of the sensor rotor that corre-
sponds to the number of active edges detected.
POSCNT can either increment or decrement, depend-
ing on a number of selectable factors which are
decoded by the QEI logic block. These include the
Count mode selected, the phase relationship of QEA to
QEB (“lead/lag”), the direction of rotation, and if a reset
event occurs. The logic is detailed in the sections that
follow.
TABLE 16-4: QEI MODES
QEIM2:
QEIM0
Mode/
Reset
Description
QEI disabled(1)
000
001
—
x2 update/ Two clocks per QEA pulse.
index pulse INDX resets POSCNT.
16.2.3.1
Edge and Phase Detect
010
x2 update/ Two clocks per QEA pulse.
In the first step, the active edges of QEA and QEB are
detected, and the phase relationship between them is
determined. The position counter is changed based on
the selected QEI mode.
period
match
POSCNT reset by the period
match (MAXCNT).
011
100
101
—
—
unused
unused
In QEI x2 Update mode, the position counter incre-
ments or decrements on every QEA edge based on the
phase relationship of the QEA and QEB signals.
x4 update/ Four clocks per QEA and
index
QEB pulse pair.
INDX resets POSCNT.
In QEI x4 Update mode, the position counter
increments or decrements on every QEA and QEB
edge based on the phase relationship of the QEA and
QEB signals. For example, if QEA leads QEB, the
position counter is incremented by 1. If QEB lags QEA,
the position counter is decremented by 1.
110
x4 update/ Four clocks per QEA and
period
match
QEB pulse pair.
POSCNT reset by the period
match (MAXCNT).
111
—
unused
Note 1: QEI module is disabled. The position
counter and the velocity measurement
functions are fully disabled in this mode.
16.2.3.2
Direction of Count
The QEI control logic generates a signal that sets
the UP/DOWN bit (QEICON<5>); this in turn
determines the direction of the count. When QEA
leads QEB, UP/DOWN is set (= 1), and the position
counter increments on every active edge. When
QEA lags QEB, UP/DOWN is cleared, and the
position counter decrements on every active edge.
16.2.2.1
QEI x2 Update Mode
QEI x2 Update mode is selected by setting the QEI
Mode Select bits (QEIM2:QEIM0) to ‘001’ or ‘010’. In
this mode, the QEI logic detects every edge on the
QEA input only. Every rising and falling edge on the
QEA signal clocks the position counter.
The position counter can be reset by either an input on
the INDX pin (QEIM2:QEIM0 = 001), or by a
period-match, even when the POSCNT register pair
equals MAXCNT (QEIM2:QEIM0 = 010).
TABLE 16-5: DIRECTION OF ROTATION
Previous Signal
Detected
Current
Signal
Detected
Pos.
Rising Falling
Cntrl.(1)
16.2.2.2
QEI 4x Update Mode
QEA QEB QEA QEB
QEI x4 Update mode provides for a finer resolution of
the rotor position, since the counter increments or
decrements more frequently for each QEA/QEB input
pulse pair than in QEI x2 mode. This mode is selected
by setting the QEI Mode Select bits to 101 or 110. In
QEI x4, the phase measurement is made on the rising
and the falling edges of both QEA and QEB inputs. The
position counter is clocked on every QEA and QEB
edge.
QEA rising
QEA falling
QEB rising
QEB falling
x
INC
DEC
DEC
INC
x
x
x
x
x
x
x
INC
DEC
INC
DEC
Like QEI x2 mode, the position counter can be reset by
an input on the pin (QEIM2:QEIM0 = 101), or by the
period-match event (QEIM2:QEIM0 = 010).
Note 1: When UP/DOWN = 1, the position
counter is incremented; when UP/DOWN
= 0, the position counter is decremented.
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16.2.4
QEI INTERRUPTS
The position counter interrupt occurs, and the interrupt
flag (IC2QEIF) is set, based on the following events:
16.2.3.3
Reset and Update Events
The position counter will continue to increment or dec-
rement until one of the following events takes place.
The type of event and the direction of rotation when it
happens determines if a register reset or update
occurs.
• A POSCNT/MAXCNT period match event
(QEIM2:QEIM0 = 010or 110)
• A POSCNT rollover (FFFFh to 0000h) in Period
mode only (QEIM2:QEIM0 = 010or 110)
• An index pulse detected on INDX.
1. An index pulse is detected on the INDX input
The interrupt timing diagrams for IC2QEIF are shown in
Figure 16-10 and Figure 16-11.
(QEIM2:QEIM0 = 001).
If the encoder is traveling in the forward direc-
tion, POSCNT is reset (00h) on the next clock
edge after the index marker, INDX, has been
detected. The position counter resets on the
QEA or QEB edge once the INDX rising edge
has been detected.
When the direction has changed, the direction change
Interrupt flag (IC3DRIF) is set on the following TCY
clock (see Figure 16-10).
If the position counter rolls over in Index mode, the
ERROR bit will be set.
If the encoder is traveling in the reverse direc-
tion, the value in the MAXCNT register is loaded
into POSCNT on the next quadrature pulse
edge (QEA or QEB) after the falling edge on
INDX has been detected.
16.2.5
QEI SAMPLE TIMING
The quadrature input signals, QEA and QEB, may vary
in quadrature frequency. The minimum quadrature
input period TQEI is 16TCY.
2. A POSTCNT/MAXCNT period match occurs
The position count rate, FPOS, is directly proportional to
the rotor’s RPM, line count D and QEI Update mode (x2
vs. x4); that is,
(QEIM2:QEIM0 = 010).
If the encoder is traveling in the forward direc-
tion, POSCNT is reset (00h) on the next clock
edge when POSCNT = MAXCNT. An interrupt
event is triggered on the next TCY after the reset
(see Figure 16-10)
4D ⋅ RPM
------------------------
=
FPOS
60
Note:
The number of incremental lines in the
position encoder is typically set at
D = 1024 and the QEI Update mode = x4.
If the encoder is traveling in the reverse
direction and the value of POSCNT reaches
00h, POSCNT is loaded with the contents of
MAXCNT register on the next clock edge. An
interrupt event is triggered on the next TCY after
the load operation (see Figure 16-10).
The maximum position count rate (i.e., 4x QEI
Update mode, D = 1024) with FCY = 10 MIPS is equal
to 2.5 MHz, which corresponds to FQEI of 625 kHz.
The value of the position counter is not affected during
QEI mode changes, nor when the QEI is disabled
altogether.
Figure 16-9 shows QEA and QEB quadrature inputs
timing when sampled by the noise filter.
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FIGURE 16-9:
QEI INPUTS WHEN SAMPLED BY THE FILTER (DIVIDE RATIO = 1:1)
TCY
QEA pin
QEB pin
(1)
TQEI = 16TCY
QEA input
QEB input
TGD = 3TCY
Note 1: The module design allows a quadrature frequency of up to FQEI = FCY/16.
FIGURE 16-10:
QEI MODULE RESET TIMING ON PERIOD MATCH
Forward
Reverse
QEA
QEB
+1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
count (+/-)
(1)
POSCNT
MAXCNT
MAXCNT=1527
Note 6
Note 2
IC2QEIF
Note 2
UP/DOWN
(3)
(3)
Q4
Q4
(5)
(4)
Q1
Q1
position
counter load
IC3DRIF
(5)
Q1
Note 1: POSCNT register is shown in QEI x4 Update mode (POSCNT increments on every rising and every falling edge of
QEA and QEB input signals). Asynchronous external QEA and QEB input are synchronized to TCY clock by the input
sampling FF in the noise filter (see Figure 16-14).
2: When POSCNT = MAXCNT, POSCNT is reset to ‘0’ on the next QEA rising edge. POSCNT is set to MAXCNT when
POSCNT = 0(when decrementing), which occurs on the next QEA falling edge.
3: IC2QEI is generated on Q4 rising edge.
4: Position counter is loaded with ‘0’ (which is a rollover event in this case) on POSCNT = MAXCNT.
5: Position counter is loaded with MAXCNT value (1527h) on underflow.
6: IC2QEIF must be cleared in software.
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FIGURE 16-11:
QEI MODULE RESET TIMING WITH THE INDEX INPUT
Forward
Reverse
Note 2
Note 2
QEA
QEB
+1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
count (+/-)
(1)
POSCNT
MAXCNT
INDX
MAXCNT=1527
Note 6
IC2QEIF
UP/DOWN
(3)
(3)
Q4
Q4
(5)
(4)
Q1
Q1
Position
counter load
Note 1: POSCNT register is shown in QEI x4 Update mode (POSCNT increments on every rising and every falling edge of
QEA and QEB input signals)
2: When INDX Reset pulse is detected, POSCNT is reset to ‘0’ on the next QEA or QEB edge. POSCNT is set to
MAXCNT when POSCNT = 0(when decrementing), which occurs on the next QEA or QEB edge. Similar Reset
sequence occurs for the reverse direction except that the INDX signal is recognized on its falling edge. The Reset
is generated on the next QEA or QEB edge.
3: IC2QEI is enabled for one TCY clock cycle.
4: Position counter is loaded with ‘0000h’ (i.e., Reset) on the next QEA or QEB edge when INDX is high.
5: Position counter is loaded with MAXCNT value (e.g., 1527h) on the next QEA or QEB edge following the INDX
falling edge input signal detect).
6: IC2QEIF must be cleared in software.
16.2.6
VELOCITY MEASUREMENT
TABLE 16-6: VELOCITY PULSES
The velocity pulse generator, in conjunction with the
IC1 and the synchronous TMR5 (in synchronous
operation), provides a method for high accuracy speed
measurements at both low and high mechanical motor
speeds. The Velocity mode is enabled when the VELM
bit is cleared (= 0) and QEI is set to one of its operating
modes (see Table 16-6).
QEIM<2:0>
Velocity Event Mode
001
010
x2 Velocity Event mode. The velocity
pulse is generated on every QEA
edge.
101
110
x4 Velocity Event mode. The velocity
pulse is generated on every QEA and
QEB active edge.
To optimize register space, the input capture channel
one (IC1) is used to capture TMR5 counter values.
Input capture buffer register, CAP1BUF, is redefined in
Velocity Measurement mode, VELM = 0, as the
Velocity Register buffer (VREGH, VREGL).
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Each velocity pulse serves as a capture pulse. With the
TMR5 in Synchronous Timer mode, the value of TMR5
is captured on every output pulse of the postscaler. The
counter is subsequently reset to ‘0’. TMR5 is reset
upon a capture event.
16.2.6.1
Velocity Event Timing
The event pulses are reduced by a fixed ratio by the
velocity pulse divider. The divider is useful for
high-speed measurements where the velocity events
happen frequently. By producing a single output pulse
for a given number of input event pulses, the counter
can track larger pulse counts (i.e., distance travelled)
for a given time interval. Time is measured by utilizing
the TMR5 time base.
Figure 16-13 shows the velocity measurement timing
diagram.
FIGURE 16-12:
VELOCITY MEASUREMENT BLOCK DIAGRAM
TMR5 Reset
Reset
Logic
QEI
Control
Logic
Clock
TMR5
TCY
16
Velocity Mode
Velocity Capture
IC1
(VELR Register)
Velocity Event
Postscaler
CAP3/QEB
QEB
QEA
INDX
Direction
Clock
Position
Counter
CAP2/QEA
CAP1/INDX
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FIGURE 16-13:
VELOCITY MEASUREMENT TIMING(1)
Forward
Reverse
QEA
QEB
vel_out
velcap
(2)
TMR5
(2)
1537
Old Value
1529
VELR
(3)
cnt_reset
Q1
Q1
Q1
(4)
IC1IF
CAP1REN
Instr.
Execution
MOVWF QEICON(5)
BCF PIE2, IC1IE
BSF PIE2, IC1IE
BCF TMR5CON, VELM
Note 1: Timing shown is for QEIM<2:0> = 101, 110or 111(x4 Update mode enabled) and the velocity postscaler divide ratio
is set to divide by 4 (PDEC<1:0> = 01).
2: VELR register latches the TMR5 count on the “velcap” capture pulse. Timer5 must be set to the synchronous timer or
Counter mode. In this example, it is set to the Synchronous Timer mode where the TMR5 prescaler divide ratio = 1
(i.e., Timer5 clock = TCY).
3: The TMR5 counter is reset on the next Q1 clock cycle following the “velcap” pulse. TMR5 value is unaffected when the
Velocity Measurement mode is first enabled (VELM = 0). The velocity postscaler values must be reconfigured to their
previous settings when re-entering Velocity Measurement mode. While making speed measurements of very slow
rotational speeds (e.g., servo-controller applications), the Velocity Measurement mode may not provide sufficient
precision. The Pulse Width Measurement mode may have to be used to provide the additional precision. In this case,
the input pulse is measured on the CAP1 input pin.
4: IC1IF interrupt is enabled by setting IC1IE as follows, BSF PIE2, IC1IE. Assume IC1E bit is placed in PIE2 Peripheral
Interrupt Enable register in the target device. The actual IC1IF bit is written on Q2 rising edge.
5: Post decimation value is changed from PDEC = 01(decimate by 4) to PDEC = 00(decimate by 1).
16.2.6.2
Velocity Postscaler
16.2.6.3
CAP1REN in Velocity Mode
The velocity event pulse (velcap, see Figure 16-12)
serves as the TMR5 capture trigger to IC1 while in the
Velocity mode. The number of velocity events are
reduced by the velocity postscaler before they are used
as the input capture clock. The velocity event reduction
ratio can be set with the PDEC1:PDEC0 control bits
(QEICON<1:0>) to 1:4, 1:16, 1:64 or no reduction (1:1).
The TMR5 value can be reset (TMR5 register pair =
0000h) on a velocity event capture by setting the
CAP1REN bit (CAP1CON<6>). When CAP1REN is
cleared, the TMR5 time base will not be reset on any
velocity event capture pulse. The VELR register pair,
however, will continue to be updated with the current
TMR5 value.
The velocity postscaler settings are automatically
reloaded from their previous values as the Velocity
mode is re-enabled.
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programmed by the FLTCK2:FLTCK0 configuration
bits. TCY is used as the clock reference to the clock
divider block.
16.3 Noise Filters
The Motion Feedback module includes three noise
rejection filters on CAP1/INDX, CAP2/QEA and
CAP3/QEB. The filter block also includes a fourth filter
for the T5CKI pin. They are intended to help reduce
spurious noise spikes which may cause the input sig-
nals to become corrupted at the inputs. The filter
ensures that the input signals are not permitted to
change until a stable value has been registered for
three consecutive sampling clock cycles.
The noise filters can either be added or removed from
the input capture or QEI signal path by setting or
clearing the appropriate FLTxEN bit, respectively. Each
capture channel provides for individual enable control
of the filter output. The FLT4EN bit enables or disabled
the noise filter available on TMR5CKI input in the
Timer5 module.
The filter network for all channels is disabled on POR
and BOR resets , as the DFLTCON register is cleared
on resets. The operation of the filter is shown in the
timing diagram in Figure 16-14.
The filters are controlled using the Digital Filter Control
(DFLTCON) register (see Register 16-3). The filters
can be individually enabled or disabled by setting or
clearing the corresponding FLTxEN bit in the
DFLTCON register. The sampling frequency, which
must be the same for all three noise filters, can be
REGISTER 16-3: DFLTCON: DIGITAL FILTER CONTROL REGISTER
U-0
—
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
FLT4EN
FLT3EN
FLT2EN
FLT1EN FLTCK2 FLTCK1
FLTCK0
bit 7
bit 0
bit 7
bit 6
Unimplemented: Read as ‘0’
FLT4EN: Noise Filter Output Enable bit, T5CKI input
1= Enabled
0= Disabled
bit 5
bit 4
bit 3
FLT3EN: Noise Filter Output Enable bit, CAP3/QEB input(1)
1= Enabled
0= Disabled
FLT2EN: Noise Filter Output Enable bit, CAP2/QEA input(1)
1= Enabled
0= Disabled
FLT1EN: Noise Filter Output Enable bit, CAP1/INDX input(1)
1= Enabled
0= Disabled
bit 2-0 FLTCK<2:0>: Noise Filter Clock Divider Ratio bits
111=Unused
110=1:128
101=1:64
100=1:32
011=1:16
010=1:4
001=1:2
000=1:1
Note 1: Noise Filter Output Enables are functional in both QEI and IC operating modes
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
Note:
The Noise Filter is intended for random high-frequency filtering and not continuous
high-frequency filtering.
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FIGURE 16-14:
FILTER TIMING DIAGRAM (CLOCK DIVIDER = 1:1)
TQEI = 16TCY
TCY
(3)
(3)
Noise glitch
Noise glitch
(1)
CAP1/INDX pin
(input to filter)
TGD = 3TCY
(2)
CAP1/INDX input
(output from filter)
Note 1: Only CAP1/INDX pin input is shown for simplicity. Similar event timing occurs on CAP2/QEA and CAP3/QEB pins.
2: Noise filtering occurs in shaded portions of CAP1 input.
3: Filter’s group delay: TGD = 3 TCY.
16.4 IC and QEI Shared Interrupts
16.5 Operation in Sleep Mode
The IC and QEI sub-modules can each generate three
distinct interrupt signals; however, they share the use
of the same three interrupt flags in register PIR3. The
meaning of a particular interrupt flag at any given time
depends on which module is active at the time the
interrupt is set. The meaning of the flags in context are
summarized in Table 16-7.
16.5.1
3X INPUT CAPTURE IN SLEEP
MODE
Since the input capture can operate only when its time
base is configured in a Synchronous mode, the input
capture will not capture any events. This is because the
device’s internal clock has been stopped, and any
internal timers in synchronous modes will not incre-
ment. The prescaler will continue to count the events
(not synchronized).
When the IC submodule is active, the three flags
(IC1IF, IC2QEIF and IC3DRIF) function as
interrupt-on-capture event flags for their respective
input capture channels. The channel must be
configured for one of the events that will generate an
interrupt (see Section 16.1.7 “IC Interrupts” for more
information).
When the specified capture event occurs, the CAPxIF
interrupt will be set. The Capture Buffer register will be
updated upon wake-up from sleep to the current TMR5
value. If the CAPxIF interrupt is enabled, the device will
wake-up from sleep. This effectively enables all input
capture channels to be used as the external interrupts.
When the QEI is enabled, the IC1IF interrupt flag
indicates an interrupt caused by
a
velocity
measurement event, usually an update of the VELR
register. The IC2QEIF interrupt indicates that a position
measurement event has occurred. IC3DRIF indicates
that a direction change has been detected.
16.5.2
QEI IN SLEEP MODE
All QEI functions are halted in Sleep mode.
TABLE 16-7: MEANING OF IC AND QEI
INTERRUPT FLAGS
Meaning
Interrupt
Flag
IC Mode
QEI Mode
IC1IF
IC1 capture
event
Velocity register
update
IC2QEIF
IC3DRIF
IC2 capture
event
Position measurement
update
IC3 capture
event
Direction change
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 179
PIC18F2331/2431/4331/4431
TABLE 16-8: REGISTERS ASSOCIATED WITH THE MOTION FEEDBACK MODULE
Value on all
other
Resets
Value on:
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
IPR3
GIE/GIEH PEIE/GIEL
TMR0IE
INT0IE
PTIP
PTIE
PTIF
RBIE
TMR0IF
IC2QEIP
IC2QEIE
IC2QEIF
INT0IF
IC1IP
IC1IE
IC1IF
RBIF
0000 000x 0000 000u
—
—
—
—
—
—
—
—
—
IC3DRIP
IC3DRIE
IC3DRIF
TMR5IP ---1 1111 ---1 1111
TMR5IE ---0 0000 ---0 0000
TMR5IF ---0 0000 ---0 0000
xxxx xxxx uuuu uuuu
PIE3
PIR3
TMR5H
TMR5L
PR5H
PR5L
Timer5 Register High Byte (Buffer)
Timer5 Register Low Byte
xxxx xxxx uuuu uuuu
Timer5 Period Register High Byte
Timer5 Period Register Low Byte
1111 1111 1111 1111
1111 1111 1111 1111
T5CON
T5SEN
RESEN
T5MOD
T5PS1
T5PS0
T5SYNC
TMR5CS TMR5ON 0000 0000 0000 0000
(1)
CAP1BUFH/ Capture 1 Register, High Byte / Velocity Register, High Byte
VELRH
xxxx xxxx uuuu uuuu
(1)
CAP1BUFL/ Capture 1 Register Low Byte / Velocity Register, Low Byte
VELRL
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
(1)
CAP2BUFH/ Capture 2 Register, High Byte / QEI Position Counter Register, High Byte
POSCNTH
(1)
CAP2BUFL/ Capture 2 Register, Low Byte / QEI Position Counter Register, Low Byte
POSCNTL
(1)
CAP3BUFH/ Capture 3 Register, High Byte / QEI Max. Count Limit Register, High Byte
MAXCNTH
(1)
CAP3BUFL/ Capture 3 Register, Low Byte / QEI Max. Count Limit Register, Low Byte
MAXCNTL
CAP1CON
CAP2CON
CAP3CON
DFLTCON
—
—
—
—
CAP1REN
CAP2REN
CAP3REN
FLT4EN
—
—
—
—
CAP1M3
CAP2M3
CAP3M3
FLT1EN
CAP1M2
CAP1M1 CAP1M0 -0-- 0000 -0-- 0000
CAP2M1 CAP2M0 -0-- 0000 -0-- 0000
CAP3M1 CAP3M0 -0-- 0000 -0-- 0000
CAP2M2
CAP3M2
FLTCK2
—
—
FLT3EN
FLT2EN
FLTCK1
PDEC1
FLTCK0 -000 0000 -000 0000
PDEC0 0000 0000 0000 0000
QEICON
VELM
ERROR
UP/DOWN
QEIM2
QEIM1
QEIM0
Legend:
x= unknown, u= unchanged, –= unimplemented, q= value depends on condition.
Shaded cells are not used by the Motion Feedback module.
Note 1:
Register name and function determined by which submodule is selected (IC/QEI, respectively). See Section 16.1.10 “Other
Operating Modes” for more information.
DS39616B-page 180
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
The PWM module has the following features:
17.0 POWER CONTROL PWM
MODULE
• Up to eight PWM I/O pins with four duty cycle
generators. Pins can be paired to get a complete
The Power Control PWM module simplifies the task of
generating multiple, synchronized pulse width
modulated (PWM) outputs for use in the control of
motor controllers and power conversion applications.
In particular, the following power and motion control
applications are supported by the PWM module:
half-bridge control.
• Up to 14-bit resolution, depending upon the PWM
period.
• “On-the-fly” PWM frequency changes.
• Edge- and Center-aligned Output modes.
• Single-pulse Generation mode.
• Three-phase and Single-phase AC Induction
Motors
• Programmable dead time control between paired
PWMs.
• Switched Reluctance Motors
• Brushless DC (BLDC) Motors
• Uninterruptible Power Supplies (UPS)
• Multiple DC Brush Motors
• Interrupt support for asymmetrical updates in
Center-aligned mode.
• Output override for Electrically Commutated
Motor (ECM) operation; for example, BLDC.
• Special Event comparator for scheduling other
peripheral events.
• PWM outputs disable feature sets PWM outputs
to their inactive state when in Debug mode.
The Power Control PWM module supports three PWM
generators and six output channels on PIC18F2X31
devices, and four generators and eight channels on
PIC18F4X31 devices. A simplified block diagram of the
module is shown in Figure 17-1. Figure 17-2 and
Figure 17-3 show how the module hardware is config-
ured for each PWM output pair for the complementary
and independent output modes.
Each functional unit of the PWM module will be
discussed in subsequent sections.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 181
PIC18F2331/2431/4331/4431
FIGURE 17-1:
POWER CONTROL PWM MODULE BLOCK DIAGRAM
Internal Data Bus
8
8
8
8
8
PWMCON0
PWM Enable and Mode
PWMCON1
DTCON
Dead Time Control
Fault Pin Control
FLTCON
OVDCON<D/S>
PWM Manual Control
(1)
PWM Generator #3
PDC3 Buffer
8
PDC3
(2)
(2)
Channel 3
Dead Time Generator
and Override Logic
PWM7
PWM6
Comparator
(2)
8
PWM Generator
#2
Channel 2
Dead Time Generator
and Override Logic
PWM5
PWM4
PTMR
Output
Driver
Block
Comparator
PTPER
PWM Generator
#1
Channel 1
Dead Time Generator
and Override Logic
PWM3
PWM2
PWM Generator
#0
Channel 0
Dead Time Generator
and Override Logic
PWM1
PWM0
8
8
PTPER Buffer
FLTA
PTCON
(2)
FLTB
Special Event
Postscaler
Comparator
Special Event Trigger
SEVTDIR
PTDIR
8
SEVTCMP
Note 1: Only PWM Generator #3 is shown in detail. The other generators are identical; their details are omitted for clarity.
2: PWM Generator #3 and its logic, PWM channels 6 and 7, and FLTB and its associated logic are not implemented
on PIC18F2X31 devices.
DS39616B-page 182
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 17-2:
PWM MODULE BLOCK DIAGRAM, ONE OUTPUT PAIR, COMPLEMENTARY
MODE
VDD
Dead-Band
Generator
PWM1
Duty Cycle Comparator
HPOL
LPOL
PWM Duty Cycle Register
PWM0
Fault Override Values
Channel Override Values
Fault A pin
Fault B pin
Fault Pin Assignment
Logic
Note:
In the Complementary mode, the even channel cannot be
forced active by a fault or override event when the odd channel
is active. The even channel is always the complement of the
odd channel and is inactive, with dead time inserted, before
the odd channel is driven to its active state.
FIGURE 17-3:
PWM MODULE BLOCK DIAGRAM, ONE OUTPUT PAIR, INDEPENDENT MODE
VDD
PWM Duty Cycle Register
PWM1
Duty Cycle Comparator
HPOL
VDD
PWM0
LPOL
Fault Override Values
Channel Override Values
Fault A pin
Fault B pin
Fault Pin Assignment
Logic
This module contains four duty-cycle generators,
numbered 0 through 3. The module has eight PWM
output pins, numbered 0 through 7. The eight PWM
outputs are grouped into output pairs of even and odd
numbered outputs. In complimentary modes, the even
PWM pins must always be the complement of the
corresponding odd PWM pin. For example, PWM0 will
be the complement of PWM1, PWM2 will be the
complement of PWM3, and so on. The dead time
generator inserts an “off” period called “dead time”
between the going off of one pin to the going on of the
complementary pin of the paired pins. This is to prevent
damage to the power switching devices that will be
connected to the PWM output pins.
The time base for the PWM module is provided by its
own 12-bit timer, which also incorporates selectable
prescaler and postscaler options.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 183
PIC18F2331/2431/4331/4431
17.1 Control Registers
17.2 Module Functionality
The operation of the PWM module is controlled by a
total of 22 registers. Eight of these are used to
configure the features of the module:
The PWM module supports several modes of operation
that are beneficial for specific power and motor control
applications. Each mode of operation is described in
subsequent sections.
• PWM Timer Control register 0 (PTCON0)
• PWM Timer Control register 1 (PTCON1)
• PWM Control register 0 (PWMCON0)
• PWM Control register 1 (PWMCON1)
• Dead Time Control register (DTCON)
• Output Override Control register (OVDCOND)
• Output State register (OVDCONS)
The PWM module is composed of several functional
blocks. The operation of each is explained separately
in relation to the several modes of operation:
• PWM Time Base
• PWM Time Base Interrupts
• PWM Period
• PWM Duty Cycle
• Fault Configuration register (FLTCONFIG)
• Dead Time Generators
• PWM Output Overrides
• PWM Fault Inputs
There are also 14 registers that are configured as
seven register pairs of 16 bits. These are used for the
configuration values of specific features. They are:
• PWM Special Event Trigger
• PWM Time Base Registers (PTMRH and PTMRL)
• PWM Period Registers (PTPERH and PTPERL)
17.3 PWM Time Base
• PWM Special Event Compare Registers
(SEVTCMPH and SEVTCMPL)
The PWM time base is provided by a 12-bit timer with
prescaler and postscaler functions. A simplified block
diagram of the PWM time base is shown in Figure 17-4.
The PWM time base is configured through the
PTCON0 and PTCON1 registers. The time base is
enabled or disabled by respectively setting or clearing
the PTEN bit in the PTCON1 register.
• PWM Duty Cycle #0 Registers
(PDC0H and PDC0L)
• PWM Duty Cycle #1 Registers
(PDC1H and PDC1L)
• PWM Duty Cycle #2 Registers
(PDC2H and PDC2L)
Note:
The PTMR register pair (PTMRL:PTMRH)
is not cleared when the PTEN bit is
cleared in software.
• PWM Duty Cycle #3 registers
(PDC3H and PDC3L)
All of these register pairs are double-buffered.
DS39616B-page 184
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 17-4:
PWM TIME BASE BLOCK DIAGRAM
PTMR Clock
PTMR Register
Timer RESET
Up/Down
Zero match
Comparator
Timer
Direction
Control
PTDIR
Period match
PTMOD1
Comparator
PTPER
Duty Cycle Load
Period load
PTPER Buffer
Update disable (UDIS)
Zero match
Period match
PTMOD1
PTMR clock
Clock
Control
PTMOD0
Prescaler
1:1, 1:4, 1:16, 1:64
PTEN
FOSC/4
Zero
match
Postscaler
1:1 - 1:16
Interrupt
Control
PTIF
Period
match
PTMOD1
PTMOD0
The PWM time base can be configured for four different
modes of operation:
• Free Running mode
• Single-shot mode
• Continuous Up/Down Count mode
• Continuous Up/Down Count mode with interrupts
for double updates
These four modes are selected by the
PTMOD1:PTMOD0 bits in the PTCON0 register. The
Free Running mode produces edge-aligned PWM
generation. The up/down counting modes produce
center-aligned PWM generation. The Single-shot
mode allows the PWM module to support pulse control
of certain electronically commutated motors (ECMs)
and produces edge-aligned operation.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 185
PIC18F2331/2431/4331/4431
REGISTER 17-1: PTCON0: PWM TIMER CONTROL REGISTER 0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
PTOPS3 PTOPS2 PTOPS1 PTOPS0 PTCKPS1 PTCKPS0 PTMOD1 PTMOD0
bit 7
bit 0
bit 7-4 PTOPS3:PTOPS0: PWM Time Base Output Postscale Select bits
0000=1:1 Postscale
0001=1:2 Postscale
.
.
.
1111=1:16 Postscale
bit 3-2 PTCKPS1:PTCKPS0: PWM Time Base Input Clock Prescale Select bits
00=PWM time base input clock is Fosc/4 (1:1 prescale)
01=PWM time base input clock is Fosc/16 (1:4 prescale)
10=PWM time base input clock is Fosc/64 (1:16 prescale)
11=PWM time base input clock is Fosc/256 (1:64 prescale)
bit 1-0 PTMOD1:PTMOD0: PWM Time Base Mode Select bits
11=PWM time base operates in a Continuous Up/Down mode with interrupts for double PWM
updates.
10=PWM time base operates in a Continuous Up/Down Counting mode.
01=PWM time base configured for Single-shot mode.
00=PWM time base operates in a Free Running mode.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
REGISTER 17-2: PTCON1: PWM TIMER CONTROL REGISTER 1
R/W-0
PTEN
R-0
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
PTDIR
bit 7
bit 0
bit 7
bit 6
PTEN: PWM Time Base Timer Enable bit
1= PWM time base is ON
0= PWM time base is OFF
PTDIR: PWM Time Base Count Direction Status bit
1= PWM time base counts down.
0= PWM time base counts up.
bit 5-0 Unimplemented: Read as ‘0’.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
‘1’= bit is set
DS39616B-page 186
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
REGISTER 17-3: PWMCON0: PWM CONTROL REGISTER 0
U-0
—
R/W-1(1) R/W-1(1) R/W-1(1)
R/W-0
R/W-0
R/W-0
R/W-0
PWMEN2 PWMEN1 PWMEN0 PMOD3(3) PMOD2
PMOD1
PMOD0
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’.
bit 6-4
PWMEN2:PWMEN0: PWM Module Enable bits(1)
111=All odd PWM I/O pins enabled for PWM output(2)
110=PWM1, PWM3 pins enabled for PWM output.
.
101=All PWM I/O pins enabled for PWM output(2)
.
100=PWM0, PWM1, PWM2, PWM3, PWM4 and PWM5 pins enabled for PWM output.
011=PWM0, PWM1, PWM2 and PWM3 I/O pins enabled for PWM output.
010=PWM0 and PWM1 pins enabled for PWM output.
001=PWM1 pin is enabled for PWM output.
000=PWM module disabled. All PWM I/O pins are general purpose I/O.
bit 3-0
PMOD3:PMOD0: PWM Output Pair Mode bits
For PMOD0:
1= PWM I/O pin pair (PWM0, PWM1) is in the Independent mode.
0= PWM I/O pin pair (PWM0, PWM1) is in the Complementary mode.
For PMOD1:
1= PWM I/O pin pair (PWM2, PWM3) is in the Independent mode.
0= PWM I/O pin pair (PWM2, PWM3) is in the Complementary mode.
For PMOD2:
1= PWM I/O pin pair (PWM4, PWM5) is in the Independent mode.
0= PWM I/O pin pair (PWM4, PWM5) is in the Complementary mode.
For PMOD3(3)
:
1= PWM I/O pin pair (PWM6, PWM7) is in the Independent mode.
0= PWM I/O pin pair (PWM6, PWM7) is in the Complementary mode.
Note 1: Reset condition of PWMEN bits depends on PWMPIN device configuration bit.
2: When PWMEN2:PWMEN0 101, PWM[5:0] outputs are enabled for
=
PIC18F2X31 devices; PWM[7:0] outputs are enabled for PIC18F4X31devices.
When PWMEN2:PWMEN0 = 111, PWM outputs 1, 3 and 5 are enabled in
PIC18F2X31devices; PWM outputs 1, 3, 5 and 7 are enabled in PIC18F4X31
devices.
3: Unimplemented in PIC18F2X31 devices; maintain these bits clear.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 187
PIC18F2331/2431/4331/4431
REGISTER 17-4: PWMCON1: PWM CONTROL REGISTER 1
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
U-0
—
R/W-0
UDIS
R/W-0
SEVOPS3 SEVOPS2 SEVOPS1 SEVOPS0 SEVTDIR
bit 7
OSYNC
bit 0
bit 7-4 SEVOPS3:SEVOPS0: PWM Special Event Trigger Output Postscale Select bits
0000=1:1 Postscale
0001=1:2 Postscale
.
.
.
1111=1:16 Postscale
bit 3
SEVTDIR: Special Event Trigger Time Base Direction bit
1= A special event trigger will occur when the PWM time base is counting downwards.
0= A special event trigger will occur when the PWM time base is counting upwards.
bit 2
bit 1
Unimplemented: Read as ‘0’.
UDIS: PWM Update Disable bit
1= Updates from duty cycle and period buffer registers are disabled.
0= Updates from duty cycle and period buffer registers are enabled.
bit 0
OSYNC: PWM Output Override Synchronization bit
1= Output overrides via the OVDCON register are synchronized to the PWM time base.
0= Output overrides via the OVDCON register are asynchronous.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared
x = bit is unknown
17.3.1
FREE RUNNING MODE
Note:
When the PWM timer is enabled in
Up/Down Count mode, during the first half
of the first period of the up/down counting
modes, the PWM outputs are kept
inactive. By doing this, PWM pins will
output garbage duty cycle due to unknown
value in the PTMR registers.
In the Free Running mode, the PWM time base
(PTMRL and PTMRH) will begin counting upwards until
the value in the Time Base Period Register, PTPER
(PTPERL and PTPERH), is matched. The PTMR regis-
ters will be reset on the following input clock edge and
the time base will continue counting upwards as long
as the PTEN bit remains set.
17.3.4
PWM TIME BASE PRESCALER
17.3.2
SINGLE-SHOT MODE
The input clock to PTMR (FOSC/4) has prescaler
options of 1:1, 1:4, 1:16 or 1:64. These are selected by
control bits PTCKPS<1:0> in the PTCON0 register. The
prescaler counter is cleared when any of the following
occurs:
In the Single-shot mode, the PWM time base will begin
counting upwards when the PTEN bit is set. When the
value in the PTMR register matches the PTPER regis-
ter, the PTMR register will be reset on the following
input clock edge and the PTEN bit will be cleared by the
hardware to halt the time base.
• Write to the PTMR register
• Write to the PTCON (PTCON0 or PTCON1)
register
17.3.3
CONTINUOUS UP/DOWN
COUNTING MODES
• Any device Reset
In continuous up/down counting modes, the PWM time
base counts upwards until the value in the PTPER
register matches with PTMR. On the following input
clock edge, the timer counts downwards. The PTDIR
bit in the PTCON1 register is read-only and indicates
the counting direction. The PTDIR bit is set when the
timer counts downwards.
Note:
The PTMR register is not cleared when
PTCON is written.
Table 17-1 shows the minimum PWM frequencies that
can be generated with the PWM time base and the
prescaler. An operating frequency of 40 MHz
(FCYC = 10 MHz) and PTPER = 0xFFF is assumed in
the table. The PWM module must be capable of gener-
ating PWM signals at the line frequency (50 Hz or
60 Hz) for certain power control applications.
DS39616B-page 188
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 17-1: MINIMUM PWM FREQUENCY
17.4 PWM Time Base Interrupts
Minimum PWM Frequencies vs. Prescaler Value
for FCYC = 10 MIPS, (PTPER = 0FFFh)
The PWM timer can generate interrupts based on the
modes of operation selected by PTMOD<1:0> bits and
the postscaler bits (PTOPS<3:0>).
PWM
PWM
Prescale
Frequency
Edge-aligned Center-aligned
Frequency
17.4.1
INTERRUPTS IN FREE RUNNING
MODE
1:1
1:4
2441 Hz
610 Hz
153 Hz
38 Hz
1221 Hz
305 Hz
76 Hz
When the PWM time base is in the Free Running mode
(PTMOD<1:0> = 00), an interrupt event is generated
each time a match with the PTPER register occurs. The
PTMR register is reset to zero in the following clock
edge.
1:16
1:64
19 Hz
17.3.5
PWM TIME BASE POSTSCALER
Using a postscaler selection other than 1:1 will reduce
the frequency of interrupt events.
The match output of PTMR can optionally be
post-scaled through a 4-bit postscaler (which gives a
1:1 to 1:16 scaling inclusive) to generate an interrupt.
The postscaler counter is cleared when any of the
following occurs:
• Write to the PTMR register
• Write to the PTCON register
• Any device Reset
The PTMR register is not cleared when PTCON is
written.
FIGURE 17-5:
PWM TIME BASE INTERRUPT TIMING, FREE RUNNING MODE
A: PRESCALER = 1:1
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
FOSC/4
PTMR
1
FFEh
FFFh
000h
001h
002h
PTMR_INT_REQ
PTIF bit
B: PRESCALER = 1:4
Q4
Q4
Qc
Qc Qc
Qc
Qc
Qc Qc
Qc
Qc
Qc Qc
Qc
Qc
Qc Qc
001h
Qc
Qc Qc Qc
Qc
1
PTMR
FFEh
FFFh
000h
002h
PTMR_INT_REQ
PTIF bit
Note 1: PWM Time Base Period register, PTPER, is loaded with the value FFFh for this example.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 189
PIC18F2331/2431/4331/4431
17.4.2
INTERRUPTS IN SINGLE-SHOT
MODE
17.4.3
INTERRUPTS IN CONTINUOUS
UP/DOWN COUNTING MODE
When the PWM time base is in the Single-shot mode
(PTMOD<1:0> = 01), an interrupt event is generated
when a match with the PTPER register occurs. The
PWM timer register (PTMR) is reset to zero on the
following input clock edge, and the PTEN bit is cleared.
The postscaler selection bits have no effect in this
Timer mode.
In the Up/Down Counting mode (PTMOD<1:0> = 10),
an interrupt event is generated each time the value of
the PTMR register becomes zero and the PWM time
base begins to count upwards. The postscaler
selection bits may be used in this mode of the timer to
reduce the frequency of the interrupt events.
Figure 17-7 shows the interrupts in continuous
Up/Down Counting mode.
FIGURE 17-6:
PWM TIME BASE INTERRUPT TIMING, SINGLE SHOT MODE
A: PRESCALER = 1:1
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
FOSC/4
2
PTMR
FFEh
FFFh
000h
000h
000h
1
1
1
PTMR_INT_REQ
PTIF bit
B: PRESCALER = 1:4
Q4
Q4
Qc
Qc Qc
Qc
Qc
Qc Qc
FFFh
Qc
Qc
Qc Qc
Qc
Qc
Qc Qc
000h
Qc
Qc
Qc Qc
000h
Qc
2
PTMR
FFEh
000h
1
1
1
PTMR_INT_REQ
PTIF bit
Note 1: Interrupt flag bit PTIF is sampled here (every Q1).
2: PWM Time Base Period register, PTPER, is loaded with the value FFFh for this example.
DS39616B-page 190
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 17-7:
PWM TIME BASE INTERRUPTS, UP/DOWN COUNTING MODE
PRESCALER = 1:1
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
FOSC/4
PTMR
002h
001h
000h
001h
002h
PTDIR bit
PTMR_INT_REQ
PTIF bit
1
1
1
1
PRESCALER = 1:4
Q4
Q4
Qc
Qc Qc
Qc
Qc
Qc Qc
001h
Qc
Qc
Qc Qc
Qc
Qc
Qc Qc
001h
Qc
Qc
Qc Qc
002h
Qc
PTMR
002h
000h
PTDIR bit
1
1
1
1
PTMR_INT_REQ
PTIF bit
Note 1: Interrupt flag bit PTIF is sampled here (every Q1).
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17.4.4
INTERRUPTS IN DOUBLE UPDATE
MODE
Note:
Do not change PTMOD while PTEN is
active. It will yield unexpected results. To
change PWM Timer mode of operation,
first clear PTEN bit, load PTMOD with
required data and then set PTEN.
This mode is available in Up/Down Counting mode. In
the Double Update mode (PTMOD<1:0> = 11), an
interrupt event is generated each time the PTMR
register is equal to zero and each time the PTMR
matches with PTPER register. Figure 17-8 shows the
interrupts in Up/Down Counting mode with double
updates.
The Double Update mode provides two additional
functions to the user in Center-Aligned mode.
1. The control loop bandwidth is doubled because
the PWM duty cycles can be updated twice per
period.
2. Asymmetrical center-aligned PWM waveforms
can be generated, which are useful for
minimizing output waveform distortion in certain
motor control applications.
FIGURE 17-8:
PWM TIME BASE INTERRUPTS, UP/DOWN COUNTING MODE WITH DOUBLE
UPDATES
A: PRESCALER = 1:1
Case 1: PTMR Counting Upwards
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
OSC1
PTMR
2
3FDh
3FEh
3FFh
3FEh
3FDh
PTDIR bit
PTMR_INT_REQ
PTIF bit
1
1
1
1
Case 2: PTMR Counting Downwards
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3
Q4
OSC1
PTMR
002h
001h
000h
001h
002h
PTDIR bit
PTMR_INT_REQ
PTIF bit
1
1
1
1
Note 1: Interrupt flag bit PTIF is sampled here (every Q1).
2: PWM Time Base Period register, PTPER, is loaded with the value 3FFh for this example.
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The maximum resolution (in bits) for a given device
oscillator and PWM frequency can be determined from
the following formula:
17.5 PWM Period
The PWM period is defined by the PTPER register pair
(PTPERL and PTPERH). The PWM period has 12-bit
resolution by combining 4 LSBs of PTPERH and 8-bits
of PTPERL. PTPER is a double-buffered register used
to set the counting period for the PWM time base.
EQUATION 17-3: PWM RESOLUTION
Fosc/4
Fpwm
log
The PTPER buffer contents are loaded into the PTPER
register at the following times:
Resolution =
log(2)
• Free Running and Single-shot modes: when the
PTMR register is reset to zero after a match with
the PTPER register.
The PWM resolutions and frequencies are shown for a
selection of execution speeds and PTPER values in
Table 17-2. The PWM frequencies in Table 17-2 are
calculated for Edge-aligned PWM mode. For
Center-aligned mode, the PWM frequencies will be
approximately one-half the values indicated in this
table.
• Up/Down Counting modes: When the PTMR
register is zero. The value held in the PTPER
buffer is automatically loaded into the PTPER
register when the PWM time base is disabled
(PTEN = 0). Figure 17-9 and Figure 17-10
indicate the times when the contents of the
PTPER buffer are loaded into the actual PTPER
register.
TABLE 17-2: EXAMPLE PWM
FREQUENCIES AND
RESOLUTIONS
The PWM period can be calculated from the following
formulas:
PWM Frequency = 1/TPWM
EQUATION 17-1: PWM PERIOD FOR FREE
RUNNING MODE
PTPER
Value
PWM
PWM
Fosc
MIPS
Resolution Frequency
40 MHz
40 MHz
40 MHz
40 MHz
40 MHz
40 MHz
40 MHz
40 MHz
40 MHz
10
10
10
10
10
10
10
10
10
0FFFh
07FFh
03FFh
01FFh
FFh
14 bits
13 bits
12 bits
11 bits
10 bits
9 bits
2.4 kHz
4.9 kHz
9.8 kHz
19.5 kHz
39.0 kHz
78.1 kHz
156.2 kHz
312.5 kHz
625 kHz
1.5 kHz
6.1 kHz
24.4 kHz
610 Hz
(PTPER + 1)
TPWM =
Fosc/(PTMRPS/4)
or
(PTPER + 1) x PTMRPS
TPWM =
Fosc/4
7Fh
3Fh
8 bits
1Fh
7 bits
EQUATION 17-2: PWM PERIOD FOR
UP/DOWN COUNTING
MODE
0Fh
6 bits
25 MHz 6.25 0FFFh
25 MHz 6.25 03FFh
14 bits
12 bits
10 bits
14 bits
12 bits
10 bits
14 bits
12 bits
10 bits
14 bits
12 bits
10 bits
25 MHz 6.25
FFh
(2 x PTPER)
TPWM =
10 MHz
10 MHz
10 MHz
5 MHz
5 MHz
5 MHz
4 MHz
4 MHz
4 MHz
2.5 0FFFh
Fosc/(PTMRPS/4)
2.5
2.5
03FFh
FFh
2.4 kHz
9.8 kHz
305 Hz
The PWM frequency is the inverse of period; or
1.25 0FFFh
1.25 03FFh
1
PWM frequency = ------------------------------
1.2 kHz
4.9 kHz
244 Hz
PWM period
1.25
FFh
0FFFh
03FFh
FFh
1
1
1
976 Hz
3.9 kHz
Note: For center-aligned operation, PWM frequencies will
be approximately 1/2 the value indicated in the table.
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FIGURE 17-9:
PWM PERIOD BUFFER UPDATES IN FREE RUNNING COUNT MODE
Period value loaded from PTPER Buffer register
7
6
New PTPER value = 007
Old PTPER value = 004
5
4
4
4
3
3
3
2
2
2
1
1
1
0
0
0
New value written to PTPER buffer.
FIGURE 17-10:
PWM PERIOD BUFFER UPDATES IN UP/DOWN COUNTING MODES
Period value loaded from
PTPER Buffer register
7
New PTPER value = 007
6
6
5
5
4
Old PTPER value = 004
4
4
3
3
3
3
2
2
2
2
1
1
1
1
0
0
0
New value written to PTPER buffer.
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The value in each Duty Cycle register determines the
amount of time that the PWM output is in the active
17.6 PWM Duty Cycle
PWM duty cycle is defined by PDCx (PDCxL and
PDCxH) registers. There are a total of 4 PWM Duty
Cycle registers for 4 pairs of PWM channels. The Duty
Cycle registers have 14-bit resolution by combining
6 LSbs of PDCxH with the 8 bits of PDCxL. PDCx is a
double-buffered register used to set the counting
period for the PWM time base.
state. The upper 12 bits of PDCn hold the actual duty
cycle value from PTMRH/L<11:0>, while the lower 2
bits control which internal Q-clock the duty cycle match
occurs. This 2-bit value is decoded from the Q-clocks
as shown in Figure 17-11 (when the prescaler is 1:1
(PTCKPS = 00)).
In Edge-aligned mode, the PWM period starts at Q1
and ends when the Duty Cycle register matches the
PTMR register as follows. The duty cycle match is con-
sidered when the upper 12 bits of the PDC is equal to
the PTMR and the lower 2 bits are equal to Q1, Q2, Q3
or Q4, depending on the lower two bits of the PDC
(when the prescaler is 1:1, or PTCKPS = 00).
17.6.1
PWM DUTY CYCLE REGISTERS
There are four 14-bit special function registers used to
specify duty cycle values for the PWM module:
• PDC0 (PDC0L and PDC0H)
• PDC1 (PDC1L and PDC1H)
• PDC2 (PDC2L and PDC2H)
• PDC3 (PDC3L and PDC3H)
Note:
When prescaler is not 1:1 (PTCKPS ≠
~00), the duty cycle match occurs at Q1
clock of the instruction cycle when the
PTMR and PDC match occurs.
Each compare unit has logic that allows override of the
PWM signals. This logic also ensures that the PWM
signals will complement each other (with dead time
insertion) in Complementary mode (see Section 17.7
“Dead Time Generators”).
FIGURE 17-11:
DUTY CYCLE COMPARISON
PTMRH<7:0>
PTMRL<7:0>
PTMR<11:0>
Q-CLOCKS(1)
PTMRL<7:0>
PTMRH<3:0>
UNUSED
<1:0>
COMPARATOR
UNUSED
PDCnH<5:0>
PDCnL<7:0>
PDCnL<7:0>
PDCn<13:0>
PDCnH<7:0>
Note 1: This value is decoded from the Q-Clocks:
00= duty cycle match occurs on Q1
01= duty cycle match occurs on Q2
10= duty cycle match occurs on Q3
11= duty cycle match occurs on Q4
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17.6.2
DUTY CYCLE REGISTER BUFFERS
17.6.3
EDGE-ALIGNED PWM
The four PWM Duty Cycle registers are
double-buffered to allow glitchless updates of the PWM
outputs. For each duty cycle block, there is a Duty
Cycle Buffer register that is accessible by the user and
a second Duty Cycle register that holds the actual
compare value used in the present PWM period.
Edge-aligned PWM signals are produced by the
module when the PWM time base is in the Free
Running mode or the Single-shot mode. For
edge-aligned PWM outputs, the output for a given
PWM channel has a period specified by the value
loaded in PTPER and a duty cycle specified by the
appropriate Duty Cycle register (see Figure 17-12).
The PWM output is driven active at the beginning of the
period (PTMR = 0) and is driven inactive when the
value in the Duty Cycle register matches PTMR. A new
cycle is started when PTMR matches the PTPER as
explained in the PWM period section.
In edge-aligned PWM Output mode, a new duty cycle
value will be updated whenever a PTMR match with the
PTPER register occurs and PTMR is reset as shown in
Figure 17-12. Also, the contents of the duty cycle
buffers are automatically loaded into the Duty Cycle
registers when the PWM time base is disabled
(PTEN = 0).
If the value in a particular Duty Cycle register is zero,
then the output on the corresponding PWM pin will be
inactive for the entire PWM period. In addition, the out-
put on the PWM pin will be active for the entire PWM
period if the value in the Duty Cycle register is greater
than the value held in the PTPER register.
When the PWM time base is in the Up/Down Counting
mode, new duty cycle values will be updated when the
value of the PTMR register is zero and the PWM time
base begins to count upwards. The contents of the duty
cycle buffers are automatically loaded into the Duty
Cycle registers when the PWM time base is disabled
(PTEN = 0). Figure 17-13 shows the timings when the
duty cycle update occur for the Up/Down Count mode.
In this mode, up to one entire PWM period is available
for calculating and loading the new PWM duty cycle
before changes take effect.
FIGURE 17-12:
EDGE-ALIGNED PWM
New Duty Cycle Latched
PTPER
PTMR
PDC
(old)
When the PWM time base is in the Up/Down Counting
mode with double updates, new duty cycle values will
be updated when the value of the PTMR register is zero
and when the value of the PTMR register matches the
value in the PTPER register. The contents of the duty
cycle buffers are automatically loaded into the Duty
Cycle registers during both of the above said
conditions. Figure 17-14 shows the duty cycle updates
for Up/Down mode with double update. In this mode,
only up to half of a PWM period is available for
calculating and loading the new PWM duty cycle before
changes take effect.
Value
PDC
(new)
0
Duty Cycle
Active at
beginning
of period
Period
FIGURE 17-13:
DUTY CYCLE UPDATE TIMES IN UP/DOWN COUNTING MODE
Duty cycle value loaded from buffer register
PWM output
PTMR Value
New value written to duty cycle buffer
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FIGURE 17-14:
DUTY CYCLE UPDATE TIMES IN UP/DOWN COUNTING MODE WITH DOUBLE
UPDATES
Duty cycle value loaded from buffer register
PWM output
PTMR Value
New values written to duty cycle buffer.
inactive for the entire PWM period. In addition, the
output on the PWM pin will be active for the entire PWM
period if the value in the Duty Cycle register is equal to
or greater than the value in the PTPER register.
17.6.4
CENTER-ALIGNED PWM
Center-aligned PWM signals are produced by the
module when the PWM time base is configured in an
Up/Down Counting mode (see Figure 17-15). The
PWM compare output is driven to the active state when
the value of the Duty Cycle register matches the value
of PTMR and the PWM time base is counting
downwards (PTDIR = 1). The PWM compare output
will be driven to the inactive state when the PWM time
base is counting upwards (PTDIR = 0) and the value in
the PTMR register matches the duty cycle value. If the
value in a particular Duty Cycle register is zero, then
the output on the corresponding PWM pin will be
Note:
When the PWM
is started in
Center-aligned mode, the period register
(PTPER) is loaded into the PWM Timer
register (PTMR) and the PTMR is
configured
automatically
to
start
down-counting. This is done to ensure that
all the PWM signals don’t start at the same
time.
FIGURE 17-15:
START OF CENTER-ALIGNED PWM
Period/2
PTPER
PTMR
Value
Duty
Cycle
0
Start of
first
Duty Cycle
PWM
Period
Period
Period
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17.6.5
COMPLEMENTARY PWM
OPERATION
FIGURE 17-16:
TYPICAL LOAD FOR
COMPLEMENTARY PWM
OUTPUTS
The Complementary mode of PWM operation is useful
to drive one or more power switches in half-bridge
configuration as shown in Figure 17-16. This inverter
topology is typical for a 3-phase induction motor,
brushless DC motor or a 3-phase Uninterruptible
Power Supply (UPS) control applications. Each
+V
3 Phase
Load
upper/lower power switch pair is fed by
a
complementary PWM signal. Dead time may be
optionally inserted during device switching where both
outputs are inactive for
a
short period (see
Section 17.7 “Dead Time Generators”). In
Complementary mode, the duty cycle comparison units
are assigned to the PWM outputs as follows:
• PDC0 register controls PWM1/PWM0 outputs
• PDC1 register controls PWM3/PWM2 outputs
• PDC2 register controls PWM5/PWM4 outputs
• PDC3 register controls PWM7/PWM6 outputs
The Complementary mode is selected for each PWM
I/O pin pair by clearing the appropriate PMODx bit in
the PWMCON0 register. The PWM I/O pins are set to
Complementary mode by default upon all kinds of
device resets.
PWM1/3/5/7 are the main PWMs that are controlled by
the PDC registers and PWM0/2/4/6 are the
complemented outputs. When using the PWMs to
control the half bridge, the odd number PWMs can be
used to control the upper power switch and the even
numbered PWMs for the lower switches.
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17.7.1
DEAD TIME INSERTION
17.7 Dead Time Generators
Each complementary output pair for the PWM module
has a 6-bit down counter used to produce the dead
time insertion. As shown in Figure 17-17, each dead
time unit has a rising and falling edge detector con-
nected to the duty cycle comparison output. The dead
time is loaded into the timer on the detected PWM edge
event. Depending on whether the edge is rising or fall-
ing, one of the transitions on the complementary out-
puts is delayed until the timer counts down to zero. A
timing diagram indicating the dead time insertion for
one pair of PWM outputs is shown in Figure 17-18.
In power inverter applications where the PWMs are
used in Complementary mode to control the upper and
lower switches of a half-bridge, a dead time insertion is
highly recommended. The dead time insertion keeps
both outputs in inactive state for a brief time. This
avoids any overlap in the switching during the state
change of the power devices due to TON and TOFF
characteristics.
Because the power output devices cannot switch
instantaneously, some amount of time must be pro-
vided between the turn-off event of one PWM output in
a complementary pair and the turn-on event of the
other transistor. The PWM module allows dead time to
be programmed. Following sections explain the dead
time block in detail.
FIGURE 17-17:
DEAD TIME CONTROL UNIT BLOCK DIAGRAM FOR ONE PWM OUTPUT PAIR
Dead Time
Select Bits
Zero Compare
Clock Control
FOSC
6-Bit Down Counter
and Prescaler
Odd PWM Signal To
Output Control Block
Dead Time
Prescale
Even PWM Signal To
Output Control Block
Dead Time Register
Duty Cycle
Compare Input
FIGURE 17-18:
DEAD TIME INSERTION FOR COMPLEMENTARY PWM
t
t
d
d
PDC1
compare
output
PWM1
PWM0
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REGISTER 17-5: DTCON – DEAD TIME CONTROL REGISTER
R/W-0
R/W-0
R/W-0
DT5
R/W-0
DT4
R/W-0
DT3
R/W-0
DT2
R/W-0
DT1
R/W-0
DT0
DTPS1
DTPS0
bit 7
bit 0
bit 7-6 DTPS1:DTPS0: Dead Time Unit A Prescale Select bits
11= Clock source for Dead Time Unit is FOSC/16.
10= Clock source for Dead Time Unit is FOSC/8.
01= Clock source for Dead Time Unit is FOSC/4.
00= Clock source for Dead Time Unit is FOSC/2.
bit 5-0 DT5:DT0: Unsigned 6-bit dead time value bits for Dead Time Unit.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
3. The dead time counter is clocked using every
other Q-clock depending on the two LSbs in the
Duty Cycle registers:
17.7.2
DEAD TIME RANGES
The amount of dead time provided by the dead time
unit is selected by specifying the input clock prescaler
value and a 6-bit unsigned value defined in the DTCON
register. Four input clock prescaler selections have
been provided to allow a suitable range of dead times
based on the device operating frequency. FOSC/2,
FOSC/4, FOSC/8 and FOSC/16 are the clock prescaler
options available using the DTPS1:DTPS0 control bits
in the DTCON register.
• If the PWM duty cycle match occurs on Q1 or
Q3, then the dead time counter is clocked
using every Q1 and Q3.
• If the PWM duty cycles match occurs on Q2
or Q4, then the dead time counter is clocked
using every Q2 and Q4.
4. When the DTPS1:DTPS0 bits are set to any of
the other dead time prescaler settings, (i.e.,
FOSC/4, FOSC/8 or FOSC/16) and the PWM Time
Base Prescaler is set to 1:1, the dead time
counter is clocked by the Q-clock corresponding
to the Q-clocks on which the PWM duty cycle
match occurs.
After selecting an appropriate prescaler value, the
dead time is adjusted by loading a 6-bit unsigned value
into DTCON<5:0>. The dead time unit prescaler is
cleared on any of the following events:
• On a load of the down timer due to a duty cycle
comparison edge event;
The actual dead time is calculated from the DTCON
register as follows:
• On a write to the DTCON register; or
• On any device Reset.
Dead Time = Dead time value / (FOSC/prescaler)
17.7.3
DECREMENTING THE DEAD TIME
COUNTER
Table 17-3 shows example dead time ranges as a
function of the input clock prescaler selected and the
device operating frequency.
The dead time counter is clocked from any of the Q
clocks based on the following conditions.
1. The dead time counter is clocked on Q1 when:
• The DTPS bits are set to any of the following
dead time prescaler settings: Fosc/4, FOSC/8,
FOSC/16
• The PWM Time Base Prescale bits
(PTCKPS) are set to any of the following
prescale ratios: FOSC/16, FOSC/64,
FOSC/256.
2. The dead time counter is clocked by a pair of
Q-clocks when the PWM Time Base Prescale
bits are set to 1:1 (PTCKPS1:PTCKPS0 = 00,
FOSC/4) and the dead time counter is clocked by
the FOSC/2 (DTPS1:DTPS0 = 00).
DS39616B-page 200
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TABLE 17-3: EXAMPLE DEAD TIME
RANGES
17.7.4
DEAD TIME DISTORTION
Note 1: For small PWM duty cycles, the ratio of
dead time to the active PWM time may
become large. In this case, the inserted
dead time will introduce distortion into
waveforms produced by the PWM mod-
ule. The user can ensure that dead time
distortion is minimized by keeping the
PWM duty cycle at least three times
larger than the dead time. A similar effect
occurs for duty cycles at or near 100%.
The maximum duty cycle used in the
application should be chosen such that
the minimum inactive time of the signal is
at least three times larger than the dead
time. If the dead time is greater or equal
to the duty cycle of one of the PWM out-
puts pairs, then that PWM pair will be
inactive for the whole period.
Fosc
(MHz)
Prescaler
Selection Time Min Time Max
Dead
Dead
MIPS
40
40
40
40
32
32
32
32
25
25
25
25
20
20
20
20
10
10
10
10
5
10
10
10
10
8
FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/2
FOSC/4
FOSC/8
FOSC/16
50 ns
100 ns
200 ns
400 ns
62.5 ns
125 ns
250 ns
500 ns
80 ns
3.2 µs
6.4 µs
12.8 µs
25.6 µs
4 µs
8
8 µs
8
16 µs
8
32 µs
6.25
6.25
6.25
6.25
5
5.12 vs
10.2 µs
20.5 µs
41 µs
160 ns
320 ns
640 ns
100 ns
200 ns
400
6.4 µs
2: Changing the dead time values in
DTCON when the PWM is enabled may
result in undesired situation. Disable the
PWM (PTEN = 0) before changing the
dead time value
5
12.8 µs
25.6 vs
51.2 µs
12.8 µs
25.6 µs
51.2 µs
102.4 µs
25.6 µs
51.2 µs
102.4 µs
204.8 µs
32 µs
5
5
800
2.5
2.5
2.5
2.5
1.25
1.25
1.25
1.25
1
200 ns
400 ns
800 ns
1.6 µs
400 ns
800 ns
1.6 µs
3.2 µs
0.5 µs
1 µs
17.8 Independent PWM Output
Independent PWM mode is used for driving the loads
as shown in Figure 17-19 for driving one winding of a
switched reluctance motor. A particular PWM output
pair is configured in the Independent Output mode
when the corresponding PMOD bit in the PWMCON0
register is set. No dead time control is implemented
between the PWM I/O pins when the module is operat-
ing in the Independent mode and both I/O pins are
allowed to be active simultaneously. This mode can
also be used to drive stepper motors.
5
5
5
4
4
1
64 µs
4
1
2 µs
128 µs
256 µs
4
1
4 µs
17.8.1
DUTY CYCLE ASSIGNMENT IN THE
INDEPENDENT MODE
In the Independent mode, each duty cycle generator is
connected to both PWM output pins in a given PWM
output pair. The odd and the even PWM output pins are
driven with a single PWM duty cycle generator. PWM1
and PWM0 are driven by the PWM channel which uses
PDC0 register to set the duty cycle, PWM3 and PWM2
with PDC1, PWM5 and PWM4 with PDC2, PWM7 and
PWM6 with PDC3, see Figure 17-3 and Register 17-3.
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OVDCOND and OVDCONS registers are used to
define the PWM override options. The OVDCOND
register contains eight bits, POVD7:POVD0, that
determine which PWM I/O pins will be overridden. The
17.8.2
PWM CHANNEL OVERRIDE
PWM output may be manually overridden for each
PWM channel by using the appropriate bits in the
OVDCOND and OVDCONS registers. The user may
select the following signal output options for each PWM
output pin operating in the Independent mode:
OVDCONS
register
contains
eight
bits,
POUT7:POUT0, that determine the state of the PWM
I/O pins when a particular output is overridden via the
POVD bits.
• I/O pin outputs PWM signal
• I/O pin inactive
The POVD bits are active-low control bits. When the
POVD bits are set, the corresponding POUT bit will
have no effect on the PWM output. In other words, the
pins corresponding to POVD bits that are set will have
the duty PWM cycle set by the PDC registers. When
one of the POVD bits is cleared, the output on the cor-
responding PWM I/O pin will be determined by the
state of the POUT bit. When a POUT bit is set, the
PWM pin will be driven to its active state. When the
POUT bit is cleared, the PWM pin will be driven to its
inactive state.
• I/O pin active
Refer to Section 17.10 “PWM Output Override” for
details for all the override functions.
FIGURE 17-19:
CENTER-CONNECTED
LOAD
+V
LOAD
PWM1
17.10.1 COMPLEMENTARY OUTPUT MODE
The even-numbered PWM I/O pin has override restric-
tions when a pair of PWM I/O pins are operating in the
Complementary mode (PMODx = 0). In Complemen-
tary mode, if the even-numbered pin is driven active by
clearing the corresponding POVD bit and by setting
POUT bits in OVDCOND and OVDCONS registers, the
output signal is forced to be the complement of the
odd-numbered I/O pin in the pair (see Figure 17-2 for
details).
PWM0
17.9 Single-Pulse PWM Operation
The single pulse PWM operation is available only in
Edge-aligned mode. In this mode, the PWM module will
produce single pulse output. Single-pulse operation is
configured when the PTMOD1:PTMOD0 bits are set to
‘01’ in PTCON0 register. This mode of operation is use-
ful for driving certain types of ECMs.
17.10.2 OVERRIDE SYNCHRONIZATION
If the OSYNC bit in the PWMCON1 register is set, all
output overrides performed via the OVDCOND and
OVDCONS registers will be synchronized to the PWM
time base. Synchronous output overrides will occur on
following conditions:
In Single-pulse mode, the PWM I/O pin(s) are driven to
the active state when the PTEN bit is set. When the
PWM timer match with Duty Cycle register occurs, the
PWM I/O pin is driven to the inactive state. When the
PWM timer match with the PTPER register occurs, the
PTMR register is cleared, all active PWM I/O pins are
driven to the inactive state, the PTEN bit is cleared, and
an interrupt is generated, if the corresponding interrupt
bit is set.
• When the PWM is in Edge-aligned mode, syn-
chronization occurs when PTMR is zero.
• When the PWM is in Center-aligned mode,
synchronization occurs when PTMR is zero and
when the value of PTMR matches PTPER.
Note 1: In the Complementary mode, the even
channel cannot be forced active by a fault
or override event when the odd channel is
active. The even channel is always the
complement of the odd channel with dead
time inserted, before the odd channel can
be driven to its active state as shown in
Figure 17-20.
Note:
PTPER and PDC values are held as it is
after the single pulse output. To have
another cycle of single pulse, only PTEN
has to be enabled.
17.10 PWM Output Override
2: Dead time inserted to the PWM channels
The PWM output override bits allow the user to manu-
ally drive the PWM I/O pins to specified logic states
independent of the duty cycle comparison units. The
PWM override bits are useful when controlling various
types of ECMs like a BLDC motor.
even when they are in Override mode.
DS39616B-page 202
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 17-20:
OVERRIDE BITS IN COMPLEMENTARY MODE
1
POUT0
POUT1
4
5
PWM1
PWM0
2
7
3
6
Assume: PVOD0 = 0; PVOD1 = 0; PMOD0 = 0
1. Even override bits have no effect in Complementary mode.
2. Odd override bit is activated, which causes the even PWM to deactivate.
3. Dead time insertion.
4. Odd PWM activated after the dead time.
5. Odd override bit is deactivated, which causes the odd PWM to deactivate.
6. Dead time insertion.
7. Even PWM is activated after the dead time.
The PWM Duty Cycle registers may be used in con-
junction with the OVDCOND and OVDCONS registers.
The Duty Cycle registers control the average voltage
across the load and the OVDCOND and OVDCONS
registers control the commutation sequence.
Figure 17-22 shows the waveforms, while Table 17-4
and Table 17-5 show the OVDCOND and OVDCONS
register values used to generate the signals.
17.10.3 OUTPUT OVERRIDE EXAMPLES
Figure 17-21 shows an example of a waveform that
might be generated using the PWM output override
feature. The figure shows a six-step commutation
sequence for a BLDC motor. The motor is driven
through a 3-phase inverter as shown in Figure 17-16.
When the appropriate rotor position is detected, the
PWM outputs are switched to the next commutation
state in the sequence. In this example, the PWM out-
puts are driven to specific logic states. The OVDCOND
and OVDCONS register values used to generate the
signals in Figure 17-21 are given in Table 17-4.
REGISTER 17-6: OVDCOND: OUTPUT OVERRIDE CONTROL REGISTER
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
POVD7(1) POVD6(1) POVD5
POVD4
POVD3
POVD2
POVD1
POVD0
bit 7
bit 0
bit 7-0 POVD7:POVD0: PWM Output Override bits(1)
1= Output on PWM I/O pin is controlled by the value in the Duty Cycle register and the PWM
time base.
0= Output on PWM I/O pin is controlled by the value in the corresponding POUT bit.
Note 1: Unimplemented in PIC18F2X31 devices; maintain these bits clear.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 203
PIC18F2331/2431/4331/4431
REGISTER 17-7: OVDCONS: OUTPUT STATE REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
POUT7(1) POUT6(1)
POUT5
POUT4
POUT3
POUT2
POUT1
POUT0
bit 7
bit 0
bit 7-0 POUT7:POUT0: PWM Manual Output bits(1)
1= Output on PWM I/O pin is ACTIVE when the corresponding PWM output override bit is
cleared.
0= Output on PWM I/O pin is INACTIVE when the corresponding PWM output override bit is
cleared.
Note 1: Unimplemented in PIC18F2X31 devices; maintain these bits clear.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
FIGURE 17-21:
PWM OUTPUT OVERRIDE
EXAMPLE #1
FIGURE 17-22:
PWM OUTPUT OVERRIDE
EXAMPLE #2
1
2
3
4
5
6
1
2
3
4
PWM5
PWM4
PWM3
PWM2
PWM1
PWM0
PWM7
PWM6
PWM5
PWM4
PWM3
PWM2
PWM1
TABLE 17-4: PWM OUTPUT OVERRIDE
EXAMPLE #1
State
OVDCOND(POVD) OVDCONS(POUT)
1
2
3
4
5
6
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00100100b
00100001b
00001001b
00011000b
00010010b
00000110b
PWM0
TABLE 17-5: PWM OUTPUT OVERRIDE
EXAMPLE #2
State OVDCOND (POVD) OVDCONS (POUT)
1
2
3
4
11000011b
11110000b
00111100b
00001111b
00000000b
00000000b
00000000b
00000000b
DS39616B-page 204
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
17.11.1 OUTPUT PIN CONTROL
17.11 PWM Output and Polarity Control
The PWMEN2:PWMEN0 control bits enable each
PWM output pin as required in the application.
There are three device configuration bits associated
with the PWM module that provide PWM output pin
control defined in CONFIG3L configuration register.
All PWM I/O pins are general purpose I/O. When a pair
of pins are enabled for PWM output, the PORT and
TRIS registers controlling the pin are disabled. Refer to
Figure 17-23 for details.
• HPOL configuration bit
• LPOL configuration bit
• PWMPIN configuration bit
These three configuration bits work in conjunction with
the three PWM enable bits (PWMEN2:PWMEN0) in the
PWMCON0 register. The configuration bits and PWM
enable bits ensure that the PWM pins are in the correct
states after a device Reset occurs.
FIGURE 17-23:
PWM I/O PIN BLOCK DIAGRAM
PWM signal from
module
1
0
PWM Pin Enable
Data Bus
D
Q
Q
VDD
P
WR PORT
CK
Data Latch
I/O Pin
D
Q
Q
N
WR TRIS
RD TRIS
CK
VSS
TRIS Latch
TTL or
Schmitt
Trigger
Q
D
EN
RD PORT
Note: I/O pin has protection diodes to VDD and VSS. PWM polarity selection logic not shown for clarity.
The LPOL configuration bit sets the output polarity for
17.11.2 OUTPUT POLARITY CONTROL
the low-side PWM outputs, PWM0, PWM2, PWM4 and
PWM6. As with HPOL, they are active-high when LPOL
is cleared, and active-low when set.
The polarity of the PWM I/O pins is set during device
programming via the HPOL and LPOL configuration
bits in the CONFIG3L device configuration register.
The HPOL configuration bit sets the output polarity for
the high-side PWM outputs, PWM1, PWM3, PWM5
and PWM7. The polarity is active-high when HPOL is
cleared (= 0), and active-low when it is set (= 1).
All output signals generated by the PWM module are
referenced to the polarity control bits, including those
generated by fault inputs or manual override (see
Section 17.10 “PWM Output Override”).
The default polarity configuration bits have the PWM
I/O pins in active-high output polarity.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 205
PIC18F2331/2431/4331/4431
17.11.3 PWM OUTPUT PIN RESET STATES
17.12.2 MFAULT INPUT MODES
The PWMPIN configuration bit determines the PWM
output pins to be PWM output pins or digital I/O pins,
after the device comes out of reset. If the PWMPIN con-
figuration bit is unprogrammed (default), the
PWMEN2:PWMEN0 control bits will be cleared on a
device Reset. Consequently, all PWM outputs will be
tri-stated and controlled by the corresponding PORT
and TRIS registers. If the PWMPIN configuration bit is
programmed low, the PWMEN2:PWMEN0 control bits
will be set as follows on a device Reset:
The FLTAMOD and FLTBMOD bits in the FLTCONFIG
register determine the modes of PWM I/O pins that are
deactivated when they are overridden by fault input.
FLTAS and FLTBS bits in the FLTCONFIG register give
the status of FaultA and FaultB inputs.
Each of the fault inputs have two modes of operation:
• Inactive Mode (FLTxMOD = 0)
This is a catastrophic Fault Management mode.
When the fault occurs in this mode, the PWM out-
puts are deactivated. The PWM pins will remain in
Inactivated mode until the fault is cleared (fault
input is driven high) and the corresponding fault
status bit has been cleared in software. The PWM
outputs are enabled immediately at the beginning
of the following PWM period, after Fault Status bit
(FLTxS) is cleared.
• PWMEN2:PWMEN0 = 101if device has 8 PWM
pins (PIC18F4X31 devices)
• PWMEN2:PWMEN0 = 100if device has 6 PWM
pins (PIC18F2X31 devices)
All PWM pins will be enabled for PWM output and will
have the output polarity defined by the HPOL and
LPOL configuration bits.
• Cycle-by-Cycle Mode (FLTxMOD = 1)
17.12 PWM Fault Inputs
When the fault occurs in this mode, the PWM out-
puts are deactivated. The PWM outputs will
remain in the defined fault states (all PWM outputs
inactive) for as long as the fault pin is held low.
After the fault pin is driven high, the PWM outputs
will return to normal operation at the beginning of
the following PWM period, and the FLTS bit is
automatically cleared.
There are two fault inputs associated with the PWM
module. The main purpose of the input fault pins is to
disable the PWM output signals and drive them into an
inactive state. The action of the fault inputs is
performed directly in hardware so that when a fault
occurs, it can be managed quickly and the PWMs
outputs are put into an inactive state to save the power
devices connected to the PWMs.
The PWM fault inputs are FLTA and FLTB, which can
come from I/O pins, the CPU or another module. The
FLTA and FLTB pins are active-low inputs so it is easy
to “OR” many sources to the same input.
The FLTCONFIG register (Register 17-8) defines the
settings of FLTA and FLTB inputs.
Note:
The inactive state of the PWM pins are
dependent on the HPOL and LPOL config-
uration bit settings, which defines the
active and inactive state for PWM outputs.
17.12.1 FAULT PIN ENABLE BITS
By setting the bits FLTAEN and FLTBEN in the
FLTCONFIG register, the corresponding fault inputs
are enabled. If both bits are cleared, then the fault
inputs have no effect on the PWM module.
DS39616B-page 206
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
17.12.3 PWM OUTPUTS WHILE IN FAULT
CONDITION
Note:
It is highly recommended to enable the
fault condition on breakpoint if a debug-
ging tool is used, while developing the
firmware and the high-power circuitry is
used. When the device is ready to pro-
gram after debugging the firmware,
BRFEN bit can be disabled.
While in the fault state (i.e., one or both FLTA and FLTB
inputs are active), the PWM output signals are driven
into their inactive states. The selection of which PWM
outputs are deactivated (while in the fault state) is
determined by the FLTCON bit in the FLTCONFIG
register as follows:
• FLTCON = 1. When FLTA or FLTB is asserted,
the PWM outputs (i.e., PWM[7:0]) are driven into
their inactive state
• FLTCON = 0. When FLTA or FLTB is asserted,
only PWM[5:0] outputs are driven inactive, leaving
PWM[7:6] activated.
Note:
Disabling only three PWM channels and
leaving one PWM channel enabled when
in the fault state, allows the flexibility to
have at least one PWM channel enabled.
None of the PWM outputs can be enabled
(driven with the PWM Duty Cycle regis-
ters) while FLTCON = 1and the fault con-
dition is present.
17.12.4 PWM OUTPUTS IN DEBUG MODE
The BRFEN bit in the FLTCONFIG register controls the
simulation of fault condition when a breakpoint is hit,
while debugging the application using a In-Circuit
Emulator (ICE) or a In-Circuit Debugger (ICD). Setting
the BRFEN to high, enables the fault condition on
breakpoint, thus driving the PWM outputs to inactive
state. This is done to avoid any continuous keeping of
status on the PWM pin, which may result in damage of
the power devices connected to the PWM outputs.
If BRFEN = 0, the fault condition on breakpoint is
disabled.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 207
PIC18F2331/2431/4331/4431
REGISTER 17-8: FLTCONFIG: FAULT CONFIGURATION REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
BRFEN FLTBS(1) FLTBMOD(1) FLTBEN(1) FLTCON
FLTAS FLTAMOD FLTAEN
bit 0
bit 7
bit 7
bit 6
BRFEN: Breakpoint Fault Enable bit
1= Enable fault condition on a breakpoint (i.e., only when HDMIN = 1)
0= Disable fault condition
FLTBS: Fault B Status bit(1)
1= FLTB is asserted;
if FLTBMOD = 0, cleared by the user
if FLTBMOD = 1, cleared automatically at beginning of the new period when FLTB is
deasserted
0= No Fault
bit 5
FLTBMOD: Fault B Mode bit(1)
1= Cycle-by-cycle mode: Pins are inactive for the remainder of the current PWM period, or until
FLTB is deasserted. FLTBS is cleared automatically when FLTB is inactive (no fault present).
0= Inactive mode: Pins are deactivated (catastrophic failure) until FLTB is deasserted and
FLTBS is cleared by the user only.
bit 4
bit 3
bit 2
FLTBEN: Fault B Enable bit(1)
1= Enable Fault B
0= Disable Fault B
FLTCON: Fault Configuration bit
1= FLTA , FLTB or both deactivates all PWM outputs
0= FLTA or FLTB deactivates PWM[5:0]
FLTAS: Fault A Status bit
1= FLTA is asserted;
If FLTAMOD = 0, cleared by the user
If FLTAMOD = 1, cleared automatically at beginning of the new period when FLTA is
deasserted.
0= No Fault
bit 1
bit 0
FLTAMOD: Fault A Mode bit
1= Cycle-by-cycle mode: Pins are inactive for the remainder of the current PWM period, or until
FLTA is deasserted. FLTAS is cleared automatically.
0= Inactive mode: Pins are deactivated (catastrophic failure) until FLTA is deasserted and
FLTAS is cleared by the user only.
FLTAEN: Fault A Enable bit
1= Enable Fault A
0= Disable Fault A
Note 1: Unimplemented in PIC18F2X31 devices; maintain these bits clear.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
DS39616B-page 208
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
17.14.1 SPECIAL EVENT TRIGGER ENABLE
The PWM module will always produce special event
trigger pulses. This signal may optionally be used by
the A/D module. Refer to Chapter 20.0 "10-bit
High-Speed Analog-to-Digital Converter (A/D)
Module" for details.
17.13 PWM Update Lockout
For a complex PWM application, the user may need to
write up to four Duty Cycle registers and the Time Base
Period Register, PTPER, at a given time. In some
applications, it is important that all buffer registers be
written before the new duty cycle and period values are
loaded for use by the module.
17.14.2 SPECIAL EVENT TRIGGER
POSTSCALER
A PWM update lockout feature may optionally be
enabled so the user may specify when new duty cycle
buffer values are valid. The PWM update lockout
feature is enabled by setting the control bit UDIS in the
PWMCON1 register. This bit affects all Duty Cycle
Buffer registers and the PWM time base period buffer,
PTPER.
The PWM special event trigger has a postscaler that
allows a 1:1 to 1:16 postscale ratio. The postscaler is
configured by writing the SEVOPS3:SEVOPS0 control
bits in the PWMCON1 register.
The special event output postscaler is cleared on any
write to the SEVTCMP register pair, or on any device
Reset.
To perform a PWM update lockout:
1. Set the UDIS bit.
2. Write all Duty Cycle registers and PTPER, if
applicable.
3. Clear the UDIS bit to re-enable updates.
4. With this, when UDIS bit is cleared, the buffer
values will be loaded to the actual registers. This
makes a synchronous loading of the registers.
17.14 PWM Special Event Trigger
The PWM module has a special event trigger capability
that allows A/D conversions to be synchronized to the
PWM time base. The A/D sampling and conversion
time may be programmed to occur at any point within
the PWM period. The special event trigger allows the
user to minimize the delay between the time when A/D
conversion results are acquired and the time when the
duty cycle value is updated.
The PWM 16-bit Special Event Trigger register
SEVTCMP (high and low), and five control bits in
PWMCON1 register are used to control its operation.
The PTMR value for which a special event trigger
should occur is loaded into the SEVTCMP register pair.
SEVTDIR bit in PWMCON1 register specifies the
counting phase when the PWM time base is in an
Up/Down Counting mode.
If the SEVTDIR bit is cleared, the special event trigger
will occur on the upward counting cycle of the PWM
time base. If SEVTDIR is set, the special event trigger
will occur on the downward count cycle of the PWM
time base. The SEVTDIR bit has effect only when PWM
timer is in the Up/Down Counting mode.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 209
PIC18F2331/2431/4331/4431
TABLE 17-6: REGISTERS ASSOCIATED WITH THE POWER CONTROL PWM MODULE
Value on:
POR,
BOR
Value on
all other
Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
GIE/GIEH PEIE/GIEL
TMR0IE
INT0IE
PTIP
PTIE
PTIF
RBIE
TMR0IF
IC2QEIP
IC2QEIE
IC2QEIF
INT0IF
IC1IP
IC1IE
IC1IF
RBIF
0000 000x 0000 000u
IPR3
—
—
—
—
—
—
—
—
IC3DRIP
IC3DRIE
IC3DRIF
TMR5IP ---1 1111 ---1 1111
TMR5IE ---0 0000 ---0 0000
TMR5IF ---0 0000 ---0 0000
PIE3
PIR3
—
PTCON0
PTCON1
PTOPS3 PTOPS2
PTEN PTDIR
PTOPS1
—
PTOPS0 PTCKPS1 PTCKPS0 PTMOD1 PTMOD0 0000 0000 0000 0000
—
—
—
—
—
—
—
00-- ---- 00-- ----
0000 0000 0000 0000
---- 0000 ---- 0000
1111 1111 1111 1111
---- 1111 ---- 1111
0000 0000 0000 0000
---- 0000 ---- 0000
(1)
PTMRL
PTMRH
PWM Time Base (lower 8 bits)
(1)
—
—
—
PWM Time Base (upper 4 bits)
(1)
PTPERL
PWM Time Base Period (lower 8 bits)
(1)
PTPERH
—
—
—
PWM Time Base Period (upper 4 bits)
(1)
(1)
SEVTCMPL
PWM Special Event Compare (lower 8 bits)
SEVTCMPH
PWMCON0
PWMCON1
DTCON
—
—
—
—
—
PWM Special Event Compare (upper 4 bits)
(2)
PWMEN2
PWMEN1 PWMEN0 PMOD3
PMOD2
—
PMOD1
UDIS
PMOD0 -101 0000 -101 0000
OSYNC 0000 0-00 0000 0-00
0000 0000 0000 0000
SEVOPS3 SEVOPS2 SEVOPS1 SEVOPS0 SEVTDIR
DTPS1
BRFEN
DTPS0 Dead Time A Value register
(2)
(2)
(2)
FLTCONFIG
OVDCOND
OVDCONS
FLTBS
FLTBMOD
POVD5
FLTBEN
FLTCON
POVD3
POUT3
FLTAS
POVD2
POUT2
FLTAMOD FLTAEN 0000 0000 0000 0000
(2)
(2)
POVD7
POUT7
POVD6
POUT6
POVD4
POUT4
POVD1
POUT1
POVD0 1111 1111 1111 1111
POUT0 0000 0000 0000 0000
--00 0000 --00 0000
0000 0000 0000 0000
0000 0000 0000 0000
--00 0000 --00 0000
0000 0000 0000 0000
--00 0000 --00 0000
0000 0000 0000 0000
--00 0000 --00 0000
(2)
(2)
POUT5
(1)
PDC0L
PWM Duty Cycle #0L register (lower 8 bits)
PWM Duty Cycle #0H register (upper 6 bits)
PWM Duty Cycle #1L register (lower 8 bits)
PWM Duty Cycle #1H register (upper 6 bits)
PWM Duty Cycle #2L register (Lower 8 bits)
PWM Duty Cycle #2H register (Upper 6 bits)
PWM Duty Cycle #3L register (Lower 8 bits)
PWM Duty Cycle #3H register (Upper 6 bits)
(1)
PDC0H
—
—
(1)
PDC1L
(1)
PDC1H
—
—
(1)
PDC2L
(1)
PDC2H
—
—
(1,2)
PDC3L
(1,2)
PDC3H
—
—
Legend:
Note 1:
2:
-= Unimplemented, u= Unchanged. Shaded cells are not used with the power control PWM.
Double-buffered register pairs. Refer to text for explanation of how these registers are read and written to.
Unimplemented in PIC18F2X31 devices; maintain these bits clear. Reset values shown are for PIC18F4X31 devices.
DS39616B-page 210
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
18.2 SPI Mode
18.0 SYNCHRONOUS SERIAL PORT
(SSP) MODULE
This section contains register definitions and opera-
tional characteristics of the SPI module. Additional
information on the SPI module can be found in the
PICmicro® Mid-Range MCU Family Reference Manual
(DS33023A).
18.1 SSP Module Overview
The Synchronous Serial Port (SSP) module is a serial
interface useful for communicating with other periph-
eral or microcontroller devices. These peripheral
devices may be Serial EEPROMs, shift registers, dis-
play drivers, A/D converters, etc. The SSP module can
operate in one of two modes:
SPI mode allows 8 bits of data to be synchronously
transmitted and received simultaneously. To accom-
plish communication, typically three pins are used:
• Serial Data Out (SDO) – RC7/RX/DT/SDO
• Serial Data In (SDI) – RC4/INT1/SDI/SDA
• Serial Clock (SCK) – RC5/INT2/SCK/SCL
• Serial Peripheral Interface (SPI™)
• Inter-Integrated Circuit (I2C™)
An overview of I2C operations and additional informa-
Additionally, a fourth pin may be used when in a Slave
mode of operation:
tion on the SSP module can be found in the PICmicro®
Mid-Range
(DS33023).
MCU
Family
Reference Manual
• Slave Select (SS) – RC6/TX/CK/SS
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits in the SSPCON register (SSPCON<5:0>)
and SSPSTAT<7:6>. These control bits allow the
following to be specified:
Refer to Application Note AN578, “Use of the SSP
module in the I 2C™ Multi-Master Environment”
(DS00578).
• Master mode (SCK is the clock output)
• Slave mode (SCK is the clock input)
• Clock polarity (Idle state of SCK)
• Clock edge (output data on rising/falling edge of
SCK)
• Clock rate (Master mode only)
• Slave Select mode (Slave mode only)
2003 Microchip Technology Inc.
Preliminary
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REGISTER 18-1: SSPSTAT: SYNC SERIAL PORT STATUS REGISTER (ADDRESS 94h)
R/W-0
SMP
R/W-0
CKE
R-0
D/A
R-0
P
R-0
S
R-0
R-0
UA
R-0
BF
R/W
bit 7
bit 0
bit 7
SMP: SPI Data Input Sample Phase bit
SPI Master mode:
1= Input data sampled at end of data output time
0= Input data sampled at middle of data output time (Microwire®)
SPI Slave mode:
SMP must be cleared when SPI is used in Slave mode
I2C mode:
This bit must be maintained clear
bit 6
CKE: SPI Clock Edge Select bit (Figure 18-2, Figure 18-3, and Figure 18-4)
SPI mode, CKP = 0:
1= Data transmitted on rising edge of SCK (Microwire® alternate)
0= Data transmitted on falling edge of SCK
SPI mode, CKP = 1:
1= Data transmitted on falling edge of SCK (Microwire® default)
0= Data transmitted on rising edge of SCK
I2C mode:
This bit must be maintained clear
bit 5
bit 4
D/A: Data/Address bit (I2C mode only)
1= Indicates that the last byte received or transmitted was data
0= Indicates that the last byte received or transmitted was address
P: Stop bit (I2C mode only)
This bit is cleared when the SSP module is disabled, or when the Start bit is detected last.
SSPEN is cleared.
1= Indicates that a Stop bit has been detected last (this bit is ‘0’ on Reset)
0= Stop bit was not detected last
bit 3
bit 2
S: Start bit (I2C mode only)
This bit is cleared when the SSP module is disabled, or when the Stop bit is detected last.
SSPEN is cleared.
1= Indicates that a Start bit has been detected last (this bit is ‘0’ on Reset)
0= Start bit was not detected last
R/W: Read/Write bit Information (I2C mode only)
This bit holds the R/W bit information following the last address match. This bit is only valid from
the address match to the next Start bit, Stop bit, or ACK bit.
1= Read
0= Write
bit 1
bit 0
UA: Update Address bit (10-bit I2C mode only)
1= Indicates that the user needs to update the address in the SSPADD register
0= Address does not need to be updated
BF: Buffer Full Status bit
Receive (SPI and I2C modes):
1= Receive complete, SSPBUF is full
0= Receive not complete, SSPBUF is empty
Transmit (I2C mode only):
1= Transmit in progress, SSPBUF is full
0= Transmit complete, SSPBUF is empty
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR reset
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Preliminary
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REGISTER 18-2: SSPCON: SYNC SERIAL PORT CONTROL REGISTER (ADDRESS 14h)
R/W-0
WCOL
R/W-0
R/W-0
R/W-0
CKP
R/W-0
R/W-0
R/W-0
R/W-0
SSPOV
SSPEN
SSPM3
SSPM2
SSPM1
SSPM0
bit 0
bit 7
bit 7
bit 6
WCOL: Write Collision Detect bit
1= The SSPBUF register is written while it is still transmitting the previous word
(must be cleared in software)
0= No collision
SSPOV: Receive Overflow Indicator bit
In SPI mode:
1= A new byte is received, while the SSPBUF register is still holding the previous data. In case
of overflow, the data in SSPSR is lost. Overflow can only occur in Slave mode. The user
must read the SSPBUF, even if only transmitting data, to avoid setting overflow. In
Master mode, the overflow bit is not set since each new reception (and transmission) is
initiated by writing to the SSPBUF register.
0= No overflow
In I2C mode:
1= A byte is received while the SSPBUF register is still holding the previous byte. SSPOV
is a “don’t care” in Transmit mode. SSPOV must be cleared in software in either mode.
0= No overflow
bit 5
SSPEN: Synchronous Serial Port Enable bit
In SPI mode:
1= Enables serial port and configures SCK, SDO and SDI as serial port pins
0= Disables serial port and configures these pins as I/O port pins
In I2C mode:
1= Enables the serial port and configures the SDA and SCL pins as serial port pins
0= Disables serial port and configures these pins as I/O port pins
In both modes, when enabled, these pins must be properly configured as input or output.
bit 4
CKP: Clock Polarity Select bit
In SPI mode:
1= Idle state for clock is a high level (Microwire® default)
0= Idle state for clock is a low level (Microwire® alternate)
In I2C mode:
SCK release control
1= Enable clock
0= Holds clock low (clock stretch). (Used to ensure data setup time.)
bit 3-0
SSPM3:SSPM0: Synchronous Serial Port Mode Select bits
0000= SPI Master mode, clock = FOSC/4
0001= SPI Master mode, clock = FOSC/16
0010= SPI Master mode, clock = FOSC/64
0011= SPI Master mode, clock = TMR2 output/2
0100= SPI Slave mode, clock = SCK pin. SS pin control enabled.
0101= SPI Slave mode, clock = SCK pin. SS pin control disabled. SS can be used as I/O pin.
0110= I2C Slave mode, 7-bit address
0111= I2C Slave mode, 10-bit address
1011= I2C Firmware Controlled Master mode (slave Idle)
1110= I2C Slave mode, 7-bit address with Start and Stop bit interrupts enabled
1111= I2C Slave mode, 10-bit address with Start and Stop bit interrupts enabled
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR reset
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To enable the serial port, SSP enable bit SSPEN
(SSPCON<5>) must be set. To reset or reconfigure SPI
mode, clear bit SSPEN, reinitialize the SSPCON
register, and then set bit SSPEN. This configures the
SDI, SDO, SCK, and SS pins as serial port pins. For the
pins to behave as the serial port function, they must
have their data direction bits (in the TRISC register)
appropriately programmed. That is:
FIGURE 18-1:
SSP BLOCK DIAGRAM
(SPI MODE)
Internal
Data Bus
Read
Write
SSPBUF reg
• SDI must have TRISC<4> set
• SDO must have TRISC<5> cleared
• SCK (Master mode) must have TRISC<3>
cleared
SSPSR reg
Shift
RC4/SDI/SDA
RC5/SDO
bit0
• SCK (Slave mode) must have TRISC<3> set
Clock
• SS must have TRISA<5> set and ADCON must
be configured such that RA5 is a digital I/O
Peripheral OE
.
Control
Enable
SS
Note 1: When the SPI is in Slave mode with SS
pin control enabled (SSPCON<3:0> =
0100), the SPI module will reset if the SS
pin is set to VDD.
RA5/SS/AN4
Edge
Select
2: If the SPI is used in Slave mode with
CKE = 1, then the SS pin control must be
enabled.
2
Clock Select
SSPM3:SSPM0
4
3: When the SPI is in Slave mode with SS
pin control enabled (SSPCON<3:0> =
0100), the state of the SS pin can affect
the state read back from the TRISC<5>
bit. The Peripheral OE signal from the
SSP module into PORTC controls the
state that is read back from the
TMR2 Output
2
Edge
Select
TCY
Prescaler
4, 16, 64
RC3/SCK/
SCL
TRISC<3>
TRISC<5>
bit
(see
Section 10.3
“PORTC, TRISC and LATC Registers”
for information on PORTC). If Read-
Modify-Write instructions, such as BSF,
are performed on the TRISC register
while the SS pin is high, this will cause the
TRISC<5> bit to be set, thus disabling the
SDO output.
DS39616B-page 214
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FIGURE 18-2:
SPI MODE TIMING, MASTER MODE
SCK (CKP = 0,
CKE = 0)
SCK (CKP = 0,
CKE = 1)
SCK (CKP = 1,
CKE = 0)
SCK (CKP = 1,
CKE = 1)
bit2
bit7
bit6
bit5
bit3
bit1
bit0
bit4
SDO
SDI (SMP = 0)
bit7
bit0
SDI (SMP = 1)
bit7
bit0
SSPIF
FIGURE 18-3:
SPI MODE TIMING (SLAVE MODE WITH CKE = 0)
SS (optional)
SCK (CKP = 0)
SCK (CKP = 1)
bit2
bit7
bit6
bit5
bit3
bit1
bit0
bit4
SDO
SDI (SMP = 0)
bit7
bit0
SSPIF
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 215
PIC18F2331/2431/4331/4431
FIGURE 18-4:
SPI MODE TIMING (SLAVE MODE WITH CKE = 1)
SS
SCK (CKP = 0)
SCK (CKP = 1)
bit2
SDO
bit7
bit6
bit5
bit3
bit1
bit0
bit4
SDI (SMP = 0)
SSPIF
bit7
bit0
TABLE 18-1: REGISTERS ASSOCIATED WITH SPI OPERATION
Value on:
POR,
BOR
Value on
all other
Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4 Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE
PEIE TMR0IE INTE RBIE TMR0IF INTF
RBIF
RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
0000 000x 0000 000u
PSPIF(1)
PSPIE(1)
ADIF
ADIE
PIE1
TRISC
PORTC Data Direction Register
1111 1111 1111 1111
xxxx xxxx uuuu uuuu
SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register
SSPCON
TRISA
WCOL
—
SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000
—
PORTA Data Direction Register
D/A R/W
--11 1111 --11 1111
0000 0000 0000 0000
SSPSTAT
SMP
CKE
P
S
UA
BF
Legend: x= unknown, u= unchanged, –= unimplemented, read as ‘0’. Shaded cells are not used by the SSP in
SPI mode.
Note 1: Bits PSPIE and PSPIF are reserved on the PIC16F73/76; always maintain these bits clear.
DS39616B-page 216
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The SSPCON register allows control of the I2C opera-
tion. Four mode selection bits (SSPCON<3:0>) allow
2
18.3 SSP I C Operation
The SSP module in I2C mode, fully implements all slave
functions, except general call support, and provides
interrupts on Start and Stop bits in hardware to facilitate
firmware implementations of the master functions. The
SSP module implements the standard mode
specifications, as well as 7-bit and 10-bit addressing.
one of the following I2C modes to be selected:
• I2C Slave mode (7-bit address)
• I2C Slave mode (10-bit address)
• I2C Slave mode (7-bit address), with Start and
Stop bit interrupts enabled to support Firmware
Master mode
• I2C Slave mode (10-bit address), with Start and
Stop bit interrupts enabled to support Firmware
Master mode
• I2C Start and Stop bit interrupts enabled to sup-
port Firmware Master mode; Slave is Idle
Selection of any I2C mode with the SSPEN bit set,
forces the SCL and SDA pins to be open-drain,
provided these pins are programmed to inputs by
setting the appropriate TRISC or TRISD bits. Pull-up
resistors must be provided externally to the SCL and
SDA pins for proper operation of the I2C module.
Additional information on SSP I2C operation can be
found in the PICmicro® Mid-Range MCU Family
Reference Manual (DS33023A).
Two pins are used for data transfer. These are the SCK/
SCL pin, which is the clock (SCL), and the SDI/SDA
pin, which is the data (SDA). The user must configure
these pins as inputs or outputs through the
TRISC<5:4> or TRISD<3:2> bits.
The SSP module functions are enabled by setting SSP
enable bit SSPEN (SSPCON<5>).
FIGURE 18-5:
SSP BLOCK DIAGRAM
(I2C MODE)
Internal
Data Bus
Read
Write
SSPBUF reg
(1)
SCK/SCL
SDI/
18.3.1
SLAVE MODE
Shift
Clock
In Slave mode, the SCL and SDA pins must be config-
ured as inputs (TRISC<5:4> or TRISD<3:2> set). The
SSP module will override the input state with the output
data when required (slave-transmitter).
SSPSR reg
MSb
LSb
(1)
SDA
When an address is matched, or the data transfer after
an address match is received, the hardware automati-
cally will generate the Acknowledge (ACK) pulse, and
then load the SSPBUF register with the received value
currently in the SSPSR register.
Addr Match
Match Detect
SSPADD reg
There are certain conditions that will cause the SSP
module not to give this ACK pulse. They include (either
or both):
Set, RESET
S, P bits
(SSPSTAT reg)
Start and
Stop bit Detect
a) The buffer full bit BF (SSPSTAT<0>) was set
before the transfer was received.
Note 1: When SSPMX = 1 in CONFIG3H:
SCK/SCL is multiplexed to pin RC5,
SDA/SDI is multiplexed to pin RC4, and
SDO is multiplexed to pin RC7.
b) The overflow bit SSPOV (SSPCON<6>) was set
before the transfer was received.
In this case, the SSPSR register value is not loaded
into the SSPBUF, but bit SSPIF (PIR1<3>) is set.
Table 18-2 shows what happens when a data transfer
byte is received, given the status of bits BF and
SSPOV. The shaded cells show the condition where
user software did not properly clear the overflow
condition. Flag bit BF is cleared by reading the
SSPBUF register, while bit SSPOV is cleared through
software.
When SSPMX = 0 in CONFIG3H:
SCK/SCL is multiplexed to pin RD3,
SDA/SDI is multiplexed to pin RD2, and
SDO is multiplexed to pin RD1.
The SSP module has five registers for I2C operation.
These are the:
• SSP Control Register (SSPCON)
• SSP Status Register (SSPSTAT)
• Serial Receive/Transmit Buffer (SSPBUF)
The SCL clock input must have a minimum high and
low for proper operation. The high and low times of the
I2C specification, as well as the requirements of the
SSP module, are shown in timing parameter #100 and
parameter #101.
• SSP Shift Register (SSPSR) – Not directly
accessible
• SSP Address Register (SSPADD)
2003 Microchip Technology Inc.
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The sequence of events for 10-bit address is as
follows, with steps 7-9 for slave-transmitter:
18.3.1.1
Addressing
Once the SSP module has been enabled, it waits for a
Start condition to occur. Following the Start condition,
the 8-bits are shifted into the SSPSR register. All
incoming bits are sampled with the rising edge of the
clock (SCL) line. The value of register SSPSR<7:1> is
compared to the value of the SSPADD register. The
address is compared on the falling edge of the eighth
clock (SCL) pulse. If the addresses match, and the BF
and SSPOV bits are clear, the following events occur:
1. Receive first (high) byte of address (bits SSPIF,
BF, and bit UA (SSPSTAT<1>) are set).
2. Update the SSPADD register with second (low)
byte of address (clears bit UA and releases the
SCL line).
3. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
4. Receive second (low) byte of address (bits
SSPIF, BF and UA are set).
a) The SSPSR register value is loaded into the
SSPBUF register.
5. Update the SSPADD register with the first (high)
byte of address. If match releases SCL line, this
will clear bit UA.
b) The buffer full bit, BF is set.
c) An ACK pulse is generated.
6. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
d) SSP interrupt flag bit, SSPIF (PIR1<3>), is set
(interrupt is generated if enabled) on the falling
edge of the ninth SCL pulse.
7. Receive Repeated Start condition.
8. Receive first (high) byte of address (bits SSPIF
and BF are set).
In 10-bit Address mode, two address bytes need to be
received by the slave (Figure 18-7). The five Most
Significant bits (MSbs) of the first address byte specify
if this is a 10-bit address. Bit R/W (SSPSTAT<2>) must
specify a write so the slave device will receive the
second address byte. For a 10-bit address, the first
byte would equal ‘1111 0 A9 A8 0’, where A9and
A8are the two MSbs of the address.
9. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
TABLE 18-2: DATA TRANSFER RECEIVED BYTE ACTIONS
Status Bits as Data
Set bit SSPIF
(SSP Interrupt occurs
if enabled)
Generate ACK
Transfer is Received
SSPSR → SSPBUF
Pulse
BF
SSPOV
0
1
1
0
0
0
1
1
Yes
No
No
No
Yes
No
No
No
Yes
Yes
Yes
Yes
Note: Shaded cells show the conditions where the user software did not properly clear the overflow condition.
18.3.1.2
Reception
When the R/W bit of the address byte is clear and an
address match occurs, the R/W bit of the SSPSTAT
register is cleared. The received address is loaded into
the SSPBUF register.
When the address byte overflow condition exists, then
no Acknowledge (ACK) pulse is given. An overflow
condition is defined as either bit BF (SSPSTAT<0>) is
set, or bit SSPOV (SSPCON<6>) is set. This is an error
condition due to the user’s firmware.
An SSP interrupt is generated for each data transfer
byte. Flag bit, SSPIF (PIR1<3>), must be cleared in
software. The SSPSTAT register is used to determine
the status of the byte.
DS39616B-page 218
Preliminary
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FIGURE 18-6:
I2C WAVEFORMS FOR RECEPTION (7-BIT ADDRESS)
R/W = 0
Receiving Address
A7 A6 A5 A4
Receiving Data
Receiving Data
ACK
9
ACK
9
ACK
9
SDA
SCL
A3 A2 A1
D7 D6 D5 D4 D3 D2
D0
8
D7 D6
D5
D4 D3
D2
D0
8
D1
7
D1
7
3
7
1
2
4
5
4
3
6
5
6
1
2
3
6
1
2
4
8
5
P
S
SSPIF (PIR1<3>)
Cleared in software
Bus Master
terminates
transfer
BF (SSPSTAT<0>)
SSPBUF register is read
SSPOV (SSPCON<6>)
Bit SSPOV is set because the SSPBUF register is still full.
ACK is not sent.
An SSP interrupt is generated for each data transfer
byte. Flag bit SSPIF must be cleared in software, and
the SSPSTAT register is used to determine the status
of the byte. Flag bit SSPIF is set on the falling edge of
the ninth clock pulse.
18.3.1.3
Transmission
When the R/W bit of the incoming address byte is set
and an address match occurs, the R/W bit of the
SSPSTAT register is set. The received address is
loaded into the SSPBUF register. The ACK pulse will
be sent on the ninth bit, and pin SCK/SCL is held low.
The transmit data must be loaded into the SSPBUF
register, which also loads the SSPSR register. Then,
pin SCK/SCL should be enabled by setting bit CKP
(SSPCON<4>). The master must monitor the SCL pin
prior to asserting another clock pulse. The slave
devices may be holding off the master by stretching the
clock. The eight data bits are shifted out on the falling
edge of the SCL input. This ensures that the SDA signal
is valid during the SCL high time (Figure 18-7).
As a slave-transmitter, the ACK pulse from the master-
receiver is latched on the rising edge of the ninth SCL
input pulse. If the SDA line was high (not ACK), then
the data transfer is complete. When the ACK is latched
by the slave, the slave logic is reset (resets SSPSTAT
register) and the slave then monitors for another
occurrence of the Start bit. If the SDA line was low
(ACK), the transmit data must be loaded into the
SSPBUF register, which also loads the SSPSR
register. Then pin SCK/SCL should be enabled by
setting bit CKP.
FIGURE 18-7:
I2C WAVEFORMS FOR TRANSMISSION (7-BIT ADDRESS)
Receiving Address
R/W = 1
ACK
Transmitting Data
ACK
9
SDA
A7 A6 A5 A4 A3 A2 A1
D7 D6 D5 D4 D3 D2 D1 D0
SCL
S
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
P
SCL held low
while CPU
responds to SSPIF
Data in
sampled
Cleared in software
SSPIF (PIR1<3>)
BF (SSPSTAT<0>)
From SSP Interrupt
Service Routine
SSPBUF is written in software
CKP (SSPCON<4>)
Set bit after writing to SSPBUF
(the SSPBUF must be written to
before the CKP bit can be set)
2003 Microchip Technology Inc.
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18.3.2
MASTER MODE
18.3.3
MULTI-MASTER MODE
Master mode of operation is supported in firmware
using interrupt generation on the detection of the Start
and Stop conditions. The Stop (P) and Start (S) bits are
cleared from a Reset or when the SSP module is
disabled. The Stop (P) and Start (S) bits will toggle
based on the Start and Stop conditions. Control of the
I2C bus may be taken when the P bit is set, or the bus
is Idle and both the S and P bits are clear.
In Multi-Master mode, the interrupt generation on the
detection of the Start and Stop conditions, allows the
determination of when the bus is free. The Stop (P) and
Start (S) bits are cleared from a Reset or when the SSP
module is disabled. The Stop (P) and Start (S) bits will
toggle based on the Start and Stop conditions. Control
of the I2C bus may be taken when bit P (SSPSTAT<4>)
is set, or the bus is Idle and both the S and P bits clear.
When the bus is busy, enabling the SSP interrupt will
generate the interrupt when the Stop condition occurs.
In Master mode, the SCL and SDA lines are manipu-
lated by clearing the corresponding TRISC<5:4> or
TRISD<3:2> bits. The output level is always low, irre-
spective of the value(s) in PORTC<5:4> or
PORTD<3:2>. So when transmitting data, a '1' data bit
must have the TRISC<4> bit set (input) and a '0' data
bit must have the TRISC<4> bit cleared (output). The
same scenario is true for the SCL line with the
TRISC<4> or TRISD<2> bit. Pull-up resistors must be
provided externally to the SCL and SDA pins for proper
operation of the I2C module.
In Multi-Master operation, the SDA line must be moni-
tored to see if the signal level is the expected output
level. This check only needs to be done when a high
level is output. If a high level is expected and a low level
is present, the device needs to release the SDA and
SCL lines (set TRISC<5:4> or TRISD<3:2> ). There are
two stages where this arbitration can be lost, these are:
• Address Transfer
• Data Transfer
The following events will cause SSP interrupt flag bit,
SSPIF, to be set (SSP Interrupt will occur if enabled):
When the slave logic is enabled, the slave continues to
receive. If arbitration was lost during the address trans-
fer stage, communication to the device may be in
progress. If addressed, an ACK pulse will be gener-
ated. If arbitration was lost during the data transfer
stage, the device will need to retransfer the data at a
later time.
• Start condition
• Stop condition
• Data transfer byte transmitted/received
Master mode of operation can be done with either the
Slave mode Idle (SSPM3:SSPM0 = 1011), or with the
Slave active. When both Master and Slave modes are
enabled, the software needs to differentiate the
source(s) of the interrupt.
TABLE 18-3: REGISTERS ASSOCIATED WITH I2C OPERATION
Value on:
POR,
BOR
Value on
all other
Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE
PEIE TMR0IE INTE
RBIE TMR0IF INTF
RBIF
0000 000x
0000 000u
0000 0000
0000 0000
uuuu uuuu
0000 0000
0000 0000
0000 0000
1111 1111
1111 1111
PSPIF(1) ADIF
PSPIE(1) ADIE
RCIF
RCIE
TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000
TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000
PIE1
SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register
SSPADD Synchronous Serial Port (I2C mode) Address Register
xxxx xxxx
0000 0000
SSPCON
SSPSTAT SMP(2) CKE(2)
TRISC(3) PORTC Data Direction Register
TRISD(3) PORTD Data Direction Register
WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000
D/A
P
S
R/W
UA
BF
0000 0000
1111 1111
1111 1111
Legend: x= unknown, u= unchanged, –= unimplemented locations read as ‘0’. Shaded cells are not used by SSP
module in I2C mode.
Note 1: PSPIF and PSPIE are reserved on the PIC16F73/76; always maintain these bits clear.
2: Maintain these bits clear in I2C mode.
3: Depending upon the setting of SSPMX in CONFIG3H, these pins are multiplexed to PORTC or PORTD.
DS39616B-page 220
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
19.1 Asynchronous Operation in
Power-Managed Modes
19.0 ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)
The USART may operate in Asynchronous mode, while
the peripheral clocks are being provided by the internal
oscillator block. This makes it possible to remove the
crystal or resonator that is commonly connected as the
primary clock on the OSC1 and OSC2 pins.
The Universal Synchronous Asynchronous Receiver
Transmitter (EUSART) module is one of the two serial
I/O modules available in the PIC18F2331/2431/4331/
4431 family of microcontrollers. EUSART is also known
as a Serial Communications Interface or SCI.
The factory calibrates the internal oscillator block out-
put (INTOSC) for 8 MHz (see Table 25-6). However,
this frequency may drift as VDD or temperature
changes, and this directly affects the asynchronous
baud rate. Two methods may be used to adjust the
baud rate clock, but both require a reference clock
source of some kind.
The EUSART can be configured as a full-duplex
asynchronous system that can communicate with
peripheral devices, such as CRT terminals and
personal computers. It can also be configured as a half-
duplex synchronous system that can communicate
with peripheral devices, such as A/D or D/A integrated
circuits, serial EEPROMs, etc.
The first (preferred) method uses the OSCTUNE
register to adjust the INTOSC output back to 8 MHz.
Adjusting the value in the OSCTUNE register allows for
fine resolution changes to the system clock source (see
Section 3.6 “INTOSC Frequency Drift” for more
information).
The EUSART module implements additional features,
including automatic baud rate detection and
calibration, automatic wake-up on sync break reception
and 12-bit break character transmit. These make it
ideally suited for use in Local Interconnect Network
(LIN) bus systems.
The other method adjusts the value in the baud rate
generator. There may not be fine enough resolution
when adjusting the Baud Rate Generator to compen-
sate for a gradual change in the peripheral clock
frequency.
The USART can be configured in the following modes:
• Asynchronous (full-duplex) with:
- Auto-Wake-up on character reception
- Auto-Baud calibration
- 12-bit break character transmission
• Synchronous – Master (half-duplex) with
selectable clock polarity
• Synchronous – Slave (half-duplex) with selectable
clock polarity
In order to configure pins RC6/TX/CK/SS and RC7/RX/
DT/SDO as the Universal Synchronous Asynchronous
Receiver Transmitter:
• SPEN (RCSTA<7>) bit must be set ( = 1),
• TRISC<6> bit must be set ( = 1), and
• TRISC<1> bit must be set ( = 1).
Note:
The USART control will automatically
reconfigure the pin from input to output as
needed.
The operation of the enhanced USART module is
controlled through three registers:
• Transmit Status and Control (TXSTA)
• Receive Status and Control (RCSTA)
• Baud Rate Control (BAUDCTL)
These are detailed in on the following pages in
Register 19-1, Register 19-2 and Register 19-3,
respectively.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 221
PIC18F2331/2431/4331/4431
REGISTER 19-1: TXSTA: TRANSMIT STATUS AND CONTROL REGISTER
R/W-0
CSRC
R/W-0
TX9
R/W-0
TXEN
R/W-0
SYNC
R/W-0
R/W-0
BRGH
R-1
R/W-0
TX9D
SENDB
TRMT
bit 7
bit 0
bit 7
CSRC: Clock Source Select bit
Asynchronous mode:
Don’t care
Synchronous mode:
1= Master mode (clock generated internally from BRG)
0= Slave mode (clock from external source)
bit 6
bit 5
TX9: 9-bit Transmit Enable bit
1= Selects 9-bit transmission
0= Selects 8-bit transmission
TXEN: Transmit Enable bit
1= Transmit enabled
0= Transmit disabled
Note:
SREN/CREN overrides TXEN in Sync mode.
bit 4
bit 3
SYNC: USART Mode Select bit
1= Synchronous mode
0= Asynchronous mode
SENDB: Send Break Character bit
Asynchronous mode:
1= Send Sync Break on next transmission (cleared by hardware upon completion)
0= Sync Break transmission completed
Synchronous mode:
Don’t care
bit 2
BRGH: High Baud Rate Select bit
Asynchronous mode:
1= High speed
0= Low speed
Synchronous mode:
Unused in this mode
bit 1
bit 0
TRMT: Transmit Shift Register Status bit
1= TSR empty
0= TSR full
TX9D: 9th bit of Transmit Data
Can be address/data bit or a parity bit.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
DS39616B-page 222
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
REGISTER 19-2: RCSTA: RECEIVE STATUS AND CONTROL REGISTER
R/W-0
SPEN
R/W-0
RX9
R/W-0
SREN
R/W-0
CREN
R/W-0
R-0
R-0
R-x
ADDEN
FERR
OERR
RX9D
bit 7
bit 0
bit 7
bit 6
bit 5
SPEN: Serial Port Enable bit
1= Serial port enabled (configures RX/DT and TX/CK pins as serial port pins)
0= Serial port disabled (held in Reset)
RX9: 9-bit Receive Enable bit
1= Selects 9-bit reception
0= Selects 8-bit reception
SREN: Single Receive Enable bit
Asynchronous mode:
Don’t care
Synchronous mode – Master:
1= Enables single receive
0= Disables single receive
This bit is cleared after reception is complete.
Synchronous mode – Slave:
Don’t care
bit 4
CREN: Continuous Receive Enable bit
Asynchronous mode:
1= Enables receiver
0= Disables receiver
Synchronous mode:
1= Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN)
0= Disables continuous receive
bit 3
ADDEN: Address Detect Enable bit
Asynchronous mode 9-bit (RX9 = 1):
1= Enables address detection, enable interrupt and load the receive buffer when RSR<8> is
set
0= Disables address detection, all bytes are received and ninth bit can be used as parity bit
Asynchronous mode 8-bit (RX9 = 0):
Don’t care
bit 2
bit 1
bit 0
FERR: Framing Error bit
1= Framing error (can be updated by reading RCREG register and receive next valid byte)
0= No framing error
OERR: Overrun Error bit
1= Overrun error (can be cleared by clearing bit CREN)
0= No overrun error
RX9D: 9th bit of Received Data
This can be address/data bit or a parity bit and must be calculated by user firmware.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 223
PIC18F2331/2431/4331/4431
REGISTER 19-3: BAUDCTL: BAUD RATE CONTROL REGISTER
U-0
—
R-1
U-0
—
R/W-0
SCKP
R/W-0
U-0
—
R/W-0
WUE
R/W-0
RCIDL
BRG16
ABDEN
bit 7
bit 0
bit 7
bit 6
Unimplemented: Read as ‘0’
RCIDL: Receive Operation Idle Status bit
1= Receiver is Idle
0= Receive in progress
bit 5
bit 4
Unimplemented: Read as ‘0’
SCKP: Synchronous Clock Polarity Select bit
Asynchronous mode:
Unused in this mode
Synchronous mode:
1= Idle state for clock (CK) is a high level
0= Idle state for clock (CK) is a low level
bit 3
BRG16: 16-bit Baud Rate Register Enable bit
1= 16-bit baud rate generator – SPBRGH and SPBRG
0= 8-bit baud rate generator – SPBRG only (Compatible mode), SPBRGH value ignored
bit 2
bit 1
Unimplemented: Read as ‘0’
WUE: Wake-up Enable bit
Asynchronous mode:
1= USART will continue to sample the RX pin – interrupt generated on falling edge; bit cleared
in hardware on following rising edge
0= RX pin not monitored or rising edge detected
Synchronous mode:
Unused in this mode
bit 0
ABDEN: Auto-Baud Detect Enable bit
Asynchronous mode:
1= Enable baud rate measurement on the next character – requires reception of a Sync field
(55h); cleared in hardware upon completion
0= Baud rate measurement disabled or completed
Synchronous mode:
Unused in this mode
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
DS39616B-page 224
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
19.2.1
POWER-MANAGED MODE
OPERATION
19.2 USART Baud Rate Generator
(BRG)
The system clock is used to generate the desired baud
rate; however, when a power-managed mode is
entered, the clock source may be operating at a
different frequency than in PRI_RUN mode. In Sleep
mode, no clocks are present and in PRI_IDLE, the
primary clock source continues to provide clocks to the
baud rate generator; however, in other power-
managed modes, the clock frequency will probably
change. This may require the value in SPBRG to be
adjusted.
The BRG is a dedicated 8-bit or 16-bit generator, that
supports both the Asynchronous and Synchronous
modes of the USART. By default, the BRG operates in
8-bit mode; setting the BRG16 bit (BAUDCTL<3>)
selects 16-bit mode.
The SPBRGH:SPBRG register pair controls the period
of a free running timer. In Asynchronous mode, bits
BRGH (TXSTA<2>) and BRG16 also control the baud
rate. In Synchronous mode, bit BRGH is ignored.
Table 19-1 shows the formula for computation of the
baud rate for different USART modes, which only apply
in Master mode (internally generated clock).
If the system clock is changed during an active receive
operation, a receive error or data loss may result. To
avoid this problem, check the status of the RCIDL bit
and make sure that the receive operation is Idle before
changing the system clock.
Given the desired baud rate and FOSC, the nearest
integer value for the SPBRGH:SPBRG registers can be
calculated using the formulas in Table 19-1. From this,
the error in baud rate can be determined. An example
calculation is shown in Example 19-1. Typical baud
rates and error values for the various asynchronous
modes are shown in Table 19-2. It may be advanta-
geous to use the high baud rate (BRGH = 1), or the 16-
bit BRG to reduce the baud rate error, or achieve a slow
baud rate for a fast oscillator frequency.
19.2.2
SAMPLING
The data on the RC7/RX/DT/SDO pin is sampled three
times by a majority detect circuit to determine if a high
or a low level is present at the RX pin.
Writing a new value to the SPBRGH:SPBRG registers
causes the BRG timer to be reset (or cleared). This
ensures the BRG does not wait for a timer overflow
before outputting the new baud rate.
TABLE 19-1: BAUD RATE FORMULAS
Configuration Bits
BRG/USART Mode
Baud Rate Formula
SYNC
BRG16
BRGH
0
0
0
0
1
1
0
0
1
1
0
1
0
1
0
1
x
x
8-bit/Asynchronous
8-bit/Asynchronous
16-bit/Asynchronous
16-bit/Asynchronous
8-bit/Synchronous
16-bit/Synchronous
FOSC/[64 (n+1)]
FOSC/[16 (n+1)]
FOSC/[4 (n+1)]
Legend: x= Don’t care, n = value of SPBRGH:SPBRG register pair
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 225
PIC18F2331/2431/4331/4431
EXAMPLE 19-1:
CALCULATING BAUD RATE ERROR
Foradevice withFOSC of16MHz,desiredbaudrateof9600,Asynchronous mode,8-bitBRG:
Desired Baud Rate= FOSC / (64 ([SPBRGH:SPBRG] + 1))
Solving for SPBRGH:SPBRG:
X
=
=
=
((Fosc / Desired Baud Rate)/64) – 1
((16000000 / 9600) / 64) – 1
[25.042] = 25
Calculated Baud Rate=16000000 / (64 (25 + 1))
=
=
=
9615
Error
(Calculated Baud Rate – Desired Baud Rate) / Desired Baud Rate
(9615 – 9600) / 9600 = 0.16%
TABLE 19-2: REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
Value on
POR, BOR
Value on all
other Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
TXSTA
CSRC
SPEN
—
TX9
RX9
TXEN
SREN
—
SYNC
SENDB BRGH
TRMT
OERR
TX9D
RX9D
0000 -010
0000 -00x
0000 -010
0000 -00x
-1-1 0-00
0000 0000
0000 0000
RCSTA
CREN ADDEN
SCKP BRG16
FERR
—
BAUDCTL
RCIDL
WUE ABDEN -1-1 0-00
0000 0000
SPBRGH Baud Rate Generator Register, High Byte
SPBRG Baud Rate Generator Register, Low Byte
0000 0000
Legend: x= unknown, – = unimplemented, read as ‘0’. Shaded cells are not used by the BRG.
TABLE 19-3: BAUD RATES FOR ASYNCHRONOUS MODES
SYNC = 0, BRGH = 0, BRG16 = 0
BAUD
RATE
(K)
FOSC = 40.000 MHz
FOSC = 20.000 MHz
FOSC = 10.000 MHz
FOSC = 8.000 MHz
Actual
Rate
(K)
SPBRG Actual
value
SPBRG Actual
value
(decimal)
SPBRG Actual
value
(decimal)
SPBRG
value
%
%
Error
%
Error
%
Error
Rate
(K)
Rate
(K)
Rate
(K)
Error
(decimal)
(decimal)
0.3
1.2
—
—
—
—
—
—
—
255
129
31
15
4
—
—
—
129
64
15
7
—
1201
2403
9615
—
—
-0.16
-0.16
-0.16
—
—
103
51
12
—
—
—
1.221
1.73
0.16
1.73
1.73
8.51
-9.58
1.202
2.404
9.766
19.531
52.083
78.125
0.16
0.16
1.73
1.73
-9.58
-32.18
2.4
2.441
9.615
19.531
56.818
125.000
1.73
0.16
1.73
-1.36
8.51
255
64
31
10
4
2.404
9.6
9.766
19.2
57.6
115.2
19.531
62.500
104.167
2
—
—
—
2
1
—
—
—
SYNC = 0, BRGH = 0, BRG16 = 0
FOSC = 2.000 MHz
BAUD
RATE
(K)
FOSC = 4.000 MHz
FOSC = 1.000 MHz
Actual
Rate
(K)
SPBRG Actual
SPBRG Actual
value
SPBRG
value
(decimal)
%
Error
%
%
Error
value
Rate
(K)
Rate
(K)
Error
(decimal)
(decimal)
0.3
1.2
0.300
1.202
0.16
0.16
207
51
25
6
300
1201
2403
—
-0.16
-0.16
-0.16
—
103
25
12
—
300
1201
—
-0.16
-0.16
—
51
12
—
—
—
—
—
2.4
2.404
0.16
9.6
8.929
-6.99
8.51
—
—
19.2
57.6
115.2
20.833
62.500
62.500
2
—
—
—
—
—
8.51
0
—
—
—
—
—
-45.75
0
—
—
—
—
—
DS39616B-page 226
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 19-3: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 1, BRG16 = 0
FOSC = 20.000 MHz FOSC = 10.000 MHz
BAUD
RATE
(K)
FOSC = 40.000 MHz
FOSC = 8.000 MHz
Actual
Rate
(K)
SPBRG Actual
SPBRG Actual
SPBRG Actual
value
SPBRG
value
(decimal)
%
Error
%
%
%
Error
value
(decimal)
Rate
(K)
value
Rate
(K)
Rate
(K)
Error
Error
(decimal)
(decimal)
2.4
9.6
—
—
—
255
129
42
—
—
—
129
64
2.441
9.615
1.73
0.16
1.73
-1.36
8.51
255
64
31
10
4
2403
9615
19230
55555
—
-0.16
-0.16
-0.16
3.55
—
207
51
25
8
9.766
1.73
0.16
0.94
-1.36
9.615
0.16
0.16
-1.36
-1.36
19.2
57.6
115.2
19.231
58.140
113.636
19.231
56.818
113.636
19.531
56.818
125.000
21
21
10
—
SYNC = 0, BRGH = 1, BRG16 = 0
FOSC = 2.000 MHz
BAUD
RATE
(K)
FOSC = 4.000 MHz
FOSC = 1.000 MHz
Actual
Rate
(K)
SPBRG Actual
SPBRG Actual
value
SPBRG
value
(decimal)
%
Error
%
%
Error
value
Rate
(K)
Rate
(K)
Error
(decimal)
(decimal)
0.3
1.2
—
—
—
207
103
25
12
3
—
1201
2403
9615
—
—
-0.16
-0.16
-0.16
—
—
103
51
12
—
300
1201
2403
—
-0.16
-0.16
-0.16
—
207
51
25
—
1.202
0.16
0.16
0.16
0.16
8.51
8.51
2.4
2.404
9.6
9.615
19.2
57.6
115.2
19.231
62.500
125.000
—
—
—
—
—
—
—
—
—
1
—
—
—
—
—
—
SYNC = 0, BRGH = 0, BRG16 = 1
BAUD
RATE
(K)
FOSC = 40.000 MHz
FOSC = 20.000 MHz
FOSC = 10.000 MHz
FOSC = 8.000 MHz
Actual
Rate
(K)
SPBRG Actual
value
(decimal)
SPBRG Actual
value
(decimal)
SPBRG Actual
value
(decimal)
SPBRG
value
%
Error
%
Error
%
Error
%
Error
Rate
(K)
Rate
(K)
Rate
(K)
(decimal)
0.3
1.2
0.300
1.200
0.00
0.02
0.06
0.16
0.16
0.94
-1.36
8332
2082
1040
259
129
42
0.300
1.200
0.02
-0.03
-0.03
0.16
4165
1041
520
129
64
0.300
1.200
0.02
-0.03
0.16
0.16
1.73
-1.36
8.51
2082
520
259
64
300
1201
2403
9615
19230
55555
—
-0.04
-0.16
-0.16
-0.16
-0.16
3.55
—
1665
415
207
51
2.4
2.402
2.399
2.404
9.6
9.615
9.615
9.615
19.2
57.6
115.2
19.231
58.140
113.636
19.231
56.818
113.636
0.16
19.531
56.818
125.000
31
25
-1.36
-1.36
21
10
8
21
10
4
—
SYNC = 0, BRGH = 0, BRG16 = 1
FOSC = 2.000 MHz
BAUD
RATE
(K)
FOSC = 4.000 MHz
FOSC = 1.000 MHz
Actual
Rate
(K)
SPBRG Actual
SPBRG Actual
value
SPBRG
value
(decimal)
%
Error
%
%
Error
value
Rate
(K)
Rate
(K)
Error
(decimal)
(decimal)
0.3
1.2
0.300
1.202
0.04
0.16
0.16
0.16
0.16
8.51
8.51
832
207
103
25
12
3
300
1201
2403
9615
—
-0.16
-0.16
-0.16
-0.16
—
415
103
51
12
—
300
1201
2403
—
-0.16
-0.16
-0.16
—
207
51
25
—
2.4
2.404
9.6
9.615
19.2
57.6
115.2
19.231
62.500
125.000
—
—
—
—
—
—
—
—
—
1
—
—
—
—
—
—
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 227
PIC18F2331/2431/4331/4431
TABLE 19-3: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
BAUD
FOSC = 40.000 MHz
FOSC = 20.000 MHz
FOSC = 10.000 MHz
FOSC = 8.000 MHz
RATE
(K)
Actual
Rate
(K)
SPBRG Actual
SPBRG Actual
SPBRG Actual
value
SPBRG
value
(decimal)
%
%
%
%
Error
value
Rate
(K)
value
Rate
(K)
Rate
(K)
Error
Error
Error
(decimal)
(decimal)
(decimal)
0.3
1.2
0.300
1.200
0.00
0.00
0.02
0.06
-0.03
0.35
-0.22
33332
8332
4165
1040
520
0.300
1.200
0.00
0.02
0.02
-0.03
0.16
-0.22
0.94
16665
4165
2082
520
259
86
0.300
1.200
0.00
0.02
0.06
0.16
0.16
0.94
-1.36
8332
2082
1040
259
129
42
300
1200
-0.01
-0.04
-0.04
-0.16
-0.16
0.79
6665
1665
832
207
103
34
2.4
2.400
2.400
2.402
2400
9.6
9.606
9.596
9.615
9615
19.2
57.6
115.2
19.193
57.803
114.943
19.231
57.471
116.279
19.231
58.140
113.636
19230
57142
117647
172
86
42
21
-2.12
16
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
FOSC = 4.000 MHz FOSC = 2.000 MHz FOSC = 1.000 MHz
BAUD
RATE
(K)
Actual
Rate
(K)
SPBRG Actual
SPBRG Actual
SPBRG
value
(decimal)
%
Error
%
Error
%
Error
value
Rate
(K)
value
Rate
(K)
(decimal)
(decimal)
0.3
1.2
0.300
1.200
0.01
0.04
0.16
0.16
0.16
2.12
-3.55
3332
832
415
103
51
300
1201
2403
9615
19230
55555
—
-0.04
-0.16
-0.16
-0.16
-0.16
3.55
—
1665
415
207
51
300
1201
2403
9615
19230
—
-0.04
-0.16
-0.16
-0.16
-0.16
—
832
207
103
25
2.4
2.404
9.6
9.615
19.2
57.6
115.2
19.231
58.824
111.111
25
12
16
8
—
8
—
—
—
—
DS39616B-page 228
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carry occurred for 8-bit modes, by checking for 00h in
the SPBRGH register. Refer to Table 19-4 for counter
clock rates to the BRG.
19.2.3
AUTO-BAUD RATE DETECT
The enhanced USART module supports the automatic
detection and calibration of baud rate. This feature is
active only in Asynchronous mode and while the WUE
bit is clear.
While the ABD sequence takes place, the USART state
machine is held in Idle. The RCIF interrupt is set once
the fifth rising edge on RX is detected. The value in the
RCREG needs to be read to clear the RCIF interrupt.
RCREG content should be discarded.
The automatic baud rate measurement sequence
(Figure 19-1) begins whenever a Start bit is received
and the ABDEN bit is set. The calculation is self-
averaging.
Note 1: If the WUE bit is set with the ABDEN bit,
auto-baud rate detection will occur on the
byte following the Break character (see
In the Auto-Baud Rate Detect (ABD) mode, the clock to
the BRG is reversed. Rather than the BRG clocking the
incoming RX signal, the RX signal is timing the BRG. In
ABD mode, the internal Baud Rate Generator is used
as a counter to time the bit period of the incoming serial
byte stream.
Section 19.3.4
“Auto-Wake-up
on
SYNC BREAK Character”).
2: It is up to the user to determine that the
incoming character baud rate is within the
range of the selected BRG clock source.
Some combinations of oscillator fre-
quency and USART baud rates are not
possible due to bit error rates. Overall
system timing and communication baud
rates must be taken into consideration
when using the Auto-Baud Rate Detec-
tion feature.
Once the ABDEN bit is set, the state machine will clear
the BRG and look for a Start bit. The Auto-Baud Detect
must receive a byte with the value 55h (ASCII “U”,
which is also the LIN bus Sync character), in order to
calculate the proper bit rate. The measurement takes
over both a low and a high bit time in order to minimize
any effects caused by asymmetry of the incoming
signal. After a Start bit, the SPBRG begins counting up
using the preselected clock source on the first rising
edge of RX. After eight bits on the RX pin, or the fifth
rising edge, an accumulated value totalling the proper
BRG period is left in the SPBRGH:SPBRG registers.
Once the 5th edge is seen (should correspond to the
Stop bit), the ABDEN bit is automatically cleared.
TABLE 19-4: BRG COUNTER CLOCK
RATES
BRG16 BRGH
BRG Counter Clock
0
0
0
1
FOSC/512
FOSC/256
While calibrating the baud rate period, the BRG regis-
ters are clocked at 1/8th the pre-configured clock rate.
Note that the BRG clock will be configured by the
BRG16 and BRGH bits. Independent of the BRG16 bit
setting, both the SPBRG and SPBRGH will be used as
a 16-bit counter. This allows the user to verify that no
1
1
0
1
FOSC/128
FOSC/32
Note:
During the ABD sequence, SPBRG and
SPBRGH are both used as a 16-bit
counter, independent of BRG16 setting.
FIGURE 19-1:
AUTOMATIC BAUD RATE CALCULATION
XXXXh
0000h
001Ch
BRG Value
Edge #2
Bit 3
Edge #3
Bit 5
Edge #4
Bit 7
Bit 6
Edge #5
Stop Bit
Edge #1
RX pin
Bit 1
Start
Bit 0
Bit 2
Bit 4
BRG Clock
Auto-Cleared
Set by User
ABDEN bit
RCIF bit
(Interrupt)
Read
RCREG
XXXXh
XXXXh
1Ch
00h
SPBRG
SPBRGH
Note 1: The ABD sequence requires the USART module to be configured in Asynchronous mode and WUE = 0.
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becomes valid in the second instruction cycle following
the load instruction. Polling TXIF immediately following
a load of TXREG will return invalid results.
19.3 USART Asynchronous Mode
The Asynchronous mode of operation is selected by
clearing the SYNC bit (TXSTA<4>). In this mode, the
USART uses standard non-return-to-zero (NRZ) format
(one Start bit, eight or nine data bits and one Stop bit).
The most common data format is 8 bits. An on-chip
dedicated 8-bit/16-bit baud rate generator can be used
to derive standard baud rate frequencies from the
oscillator.
While flag bit TXIF indicates the status of the TXREG
register, another bit, TRMT (TXSTA<1>), shows the
status of the TSR register. Status bit TRMT is a read-
only bit, which is set when the TSR register is empty.
No interrupt logic is tied to this bit, so the user has to
poll this bit in order to determine if the TSR register is
empty.
The USART transmits and receives the LSb first. The
USART’s transmitter and receiver are functionally inde-
pendent, but use the same data format and baud rate.
The baud rate generator produces a clock, either x16
or x64 of the bit shift rate, depending on the BRGH and
BRG16 bits (TXSTA<2> and BAUDCTL<3>). Parity is
not supported by the hardware, but can be
implemented in software and stored as the 9th data bit.
Note 1: The TSR register is not mapped in data
memory, so it is not available to the user.
2: Flag bit TXIF is set when enable bit TXEN
is set.
To set up an Asynchronous Transmission:
1. Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
Asynchronous mode is available in all low-power
modes; it is available in Sleep mode only when Auto-
Wake-up on Sync Break is enabled. When in PRI_IDLE
mode, no changes to the baud rate generator values
are required; however, other low-power mode clocks
may operate at another frequency than the primary
clock. Therefore, the baud rate generator values may
need to be adjusted.
2. Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
3. If interrupts are desired, set enable bit TXIE.
4. If 9-bit transmission is desired, set transmit bit
TX9. Can be used as address/data bit.
5. Enable the transmission by setting bit TXEN,
which will also set bit TXIF.
When operating in Asynchronous mode, the USART
module consists of the following important elements:
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
• Baud Rate Generator
• Sampling Circuit
7. Load data to the TXREG register (starts
transmission).
• Asynchronous Transmitter
• Asynchronous Receiver
If using interrupts, ensure that the GIE and PEIE bits in
the INTCON register (INTCON<7:6>) are set.
• Auto-Wake-up on Sync Break Character
• 12-bit Break Character Transmit
• Auto-Baud Rate Detection
19.3.1
USART ASYNCHRONOUS
TRANSMITTER
The USART transmitter block diagram is shown in
Figure 19-2. The heart of the transmitter is the Transmit
(serial) Shift Register (TSR). The shift register obtains
its data from the read/write transmit buffer, TXREG. The
TXREG register is loaded with data in software. The
TSR register is not loaded until the Stop bit has been
transmitted from the previous load. As soon as the Stop
bit is transmitted, the TSR is loaded with new data from
the TXREG register (if available).
Once the TXREG register transfers the data to the TSR
register (occurs in one TCY), the TXREG register is
empty and flag bit TXIF (PIR1<4>) is set. This interrupt
can be enabled/disabled by setting/clearing enable bit
TXIE (PIE1<4>). Flag bit TXIF will be set, regardless of
the state of enable bit TXIE and cannot be cleared in
software. Flag bit TXIF is not cleared immediately upon
loading the transmit buffer register TXREG. TXIF
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FIGURE 19-2:
USART TRANSMIT BLOCK DIAGRAM
Data Bus
TXREG Register
TXIF
TXIE
8
RC6/TX/CK/SS pin
MSb
(8)
LSb
0
Pin Buffer
and Control
•
•
•
TSR Register
Interrupt
Baud Rate CLK
SPBRG
TXEN
TRMT
SPEN
BRG16
SPBRGH
TX9
TX9D
Baud Rate Generator
FIGURE 19-3:
ASYNCHRONOUS TRANSMISSION
Write to TXREG
Word 1
BRG Output
(Shift Clock)
RC6/TX/CK/SS
(pin)
Start bit
bit 0
bit 1
Word 1
bit 7/8
Stop bit
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
1 TCY
Word 1
Transmit Shift Reg
TRMT bit
(Transmit Shift
Reg. Empty Flag)
FIGURE 19-4:
ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
Write to TXREG
Word 2
Start bit
Word 1
BRG Output
(Shift Clock)
RC6/TX/CK/SS
(pin)
Start bit
Word 2
bit 0
bit 1
bit 7/8
bit 0
Stop bit
1 TCY
Word 1
TXIF bit
(Interrupt Reg. Flag)
1 TCY
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Word 1
Transmit Shift Reg.
Word 2
Transmit Shift Reg.
Note:
This timing diagram shows two consecutive transmissions.
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TABLE 19-5: REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE
—
TMR0IF INT0IF
RBIF
0000 000x 0000 000u
-000 -000 -000 -000
-000 -000 -000 -000
-111 -111 -111 -111
0000 -00x 0000 -00x
0000 0000 0000 0000
0000 0010 0000 0010
-1-1 0-00 -1-1 0-00
0000 0000 0000 0000
0000 0000 0000 0000
—
—
ADIF
ADIE
ADIP
RX9
RCIF
RCIE
RCIP
SREN
TXIF
TXIE
TXIP
CCP1IF TMR2IF TMR1IF
CCP1IE TMR2IE TMR1IE
CCP1IP TMR2IP TMR1IP
PIE1
—
IPR1
—
—
RCSTA
TXREG
TXSTA
BAUDCTL
SPEN
CREN ADDEN
FERR
OERR
RX9D
USART Transmit Register
CSRC
—
TX9
TXEN
—
SYNC SENDB BRGH
SCKP BRG16
TRMT
WUE
TX9D
RCIDL
—
ABDEN
SPBRGH Baud Rate Generator Register, High Byte
SPBRG
Baud Rate Generator Register, Low Byte
Legend:
x= unknown, –= unimplemented locations read as ‘0’. Shaded cells are not used for Asynchronous Transmission.
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19.3.2
USART ASYNCHRONOUS
RECEIVER
19.3.3
SETTING UP 9-BIT MODE WITH
ADDRESS DETECT
The receiver block diagram is shown in Figure 19-5.
The data is received on the RC7/RX/DT/SDO pin and
drives the data recovery block. The data recovery block
is actually a high-speed shifter operating at x16 times
the baud rate, whereas the main receive serial shifter
operates at the bit rate or at FOSC. This mode would
typically be used in RS-232 systems.
This mode would typically be used in RS-485 systems.
To set up an Asynchronous Reception with Address
Detect Enable:
1. Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
To set up an Asynchronous Reception:
2. Enable the asynchronous serial port by clearing
the SYNC bit and setting the SPEN bit.
1. Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
3. If interrupts are required, set the RCEN bit and
select the desired priority level with the RCIP bit.
4. Set the RX9 bit to enable 9-bit reception.
5. Set the ADDEN bit to enable address detect.
6. Enable reception by setting the CREN bit.
2. Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
3. If interrupts are desired, set enable bit RCIE.
4. If 9-bit reception is desired, set bit RX9.
5. Enable the reception by setting bit CREN.
7. The RCIF bit will be set when reception is com-
plete. The interrupt will be Acknowledged if the
RCIE and GIE bits are set.
6. Flag bit RCIF will be set when reception is com-
plete and an interrupt will be generated if enable
bit RCIE was set.
8. Read the RCSTA register to determine if any
error occurred during reception, as well as read
bit 9 of data (if applicable).
7. Read the RCSTA register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
9. Read RCREG to determine if the device is being
addressed.
10. If any error occurred, clear the CREN bit.
8. Read the 8-bit received data by reading the
RCREG register.
11. If the device has been addressed, clear the
ADDEN bit to allow all received data into the
receive buffer and interrupt the CPU.
9. If any error occurred, clear the error by clearing
enable bit CREN.
10. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
FIGURE 19-5:
USART RECEIVE BLOCK DIAGRAM
CREN
OERR
FERR
x64 Baud Rate CLK
SPBRGH SPBRG
÷ 64
RSR Register
• • •
MSb
Stop
LSb
BRG16
or
÷ 16
Start
(8)
7
1
0
or
Baud Rate Generator
÷ 4
RX9
RC7/RX/DT/SDO
Pin Buffer
and Control
Data
Recovery
RX9D
RCREG Register
FIFO
SPEN
8
Interrupt
RCIF
RCIE
Data Bus
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To set up an Asynchronous Transmission:
4. If 9-bit transmission is desired, set transmit bit
TX9. Can be used as address/data bit.
1. Initialize the SPBRG register for the appropriate
baud rate. If a high-speed baud rate is desired,
set bit BRGH (see Section 19.2 “USART Baud
Rate Generator (BRG)”).
5. Enable the transmission by setting bit TXEN,
which will also set bit TXIF.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
2. Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
7. Load data to the TXREG register (starts
transmission).
3. If interrupts are desired, set enable bit TXIE.
If using interrupts, ensure that the GIE and PEIE bits in
the INTCON register (INTCON<7:6>) are set.
FIGURE 19-6:
ASYNCHRONOUS RECEPTION
Start
bit
Start
bit
Start
bit
RX (pin)
bit0
bit1
Stop
bit
Stop
bit
bit7/8 Stop
bit
bit0
bit7/8
bit7/8
Rcv Shift
Reg
Rcv Buffer Reg
Word 2
RCREG
Word 1
RCREG
Read Rcv
Buffer Reg
RCREG
RCIF
(Interrupt Flag)
OERR bit
CREN
Note:
This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after
the third word, causing the OERR (overrun) bit to be set.
TABLE 19-6: REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE
—
TMR0IF INT0IF
RBIF
0000 000x
0000 000u
-000 -000
-000 -000
-111 -111
—
—
ADIF
ADIE
ADIP
RX9
RCIF
RCIE
RCIP
SREN
TXIF
TXIE
TXIP
CCP1IF TMR2IF TMR1IF -000 -000
CCP1IE TMR2IE TMR1IE -000 -000
CCP1IP TMR2IP TMR1IP -111 -111
PIE1
—
IPR1
—
—
RCSTA
SPEN
CREN ADDEN FERR
OERR
RX9D
0000 -00x
0000 -00x
RCREG
USART Receive Register
0000 0000
0000 0010
0000 0000
0000 0010
-1-1 0-00
0000 0000
0000 0000
TXSTA
CSRC
—
TX9
TXEN
—
SYNC SENDB BRGH
TRMT
WUE
TX9D
BAUDCTL
RCIDL
SCKP BRG16
—
ABDEN -1-1 0-00
0000 0000
SPBRGH Baud Rate Generator Register, High Byte
SPBRG
Baud Rate Generator Register, Low Byte
0000 0000
Legend:
x= unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for Asynchronous Reception.
DS39616B-page 234
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properly, therefore, the initial character in the
transmission must be all ‘0’s. This can be 00h (8 bytes)
for standard RS-232 devices, or 000h (12 bits) for LIN
bus.
19.3.4
AUTO-WAKE-UP ON SYNC BREAK
CHARACTER
During Sleep mode, all clocks to the USART are sus-
pended. Because of this, the baud rate generator is
inactive and a proper byte reception cannot be per-
formed. The Auto-Wake-up feature allows the control-
ler to wake-up due to activity on the RX/DT line, while
the USART is operating in Asynchronous mode.
Oscillator start-up time must also be considered, espe-
cially in applications using oscillators with longer start-
up intervals (i.e., LP, XT or HS/PLL mode). The sync
break (or wake-up signal) character must be of suffi-
cient length, and be followed by a sufficient interval, to
allow enough time for the selected oscillator to start
and provide proper initialization of the USART.
The Auto-Wake-up feature is enabled by setting the
WUE bit (BAUDCTL<1>). Once set, the typical receive
sequence on RX/DT is disabled, and the USART
remains in an Idle state, monitoring for a wake-up event
independent of the CPU mode. A wake-up event con-
sists of a high-to-low transition on the RX/DT line. (This
coincides with the start of a Sync Break or a Wake-up
Signal character for the LIN protocol.)
19.3.4.2
Special Considerations Using the
WUE Bit
The timing of WUE and RCIF events may cause some
confusion when it comes to determining the validity of
received data. As noted, setting the WUE bit places the
USART in an Idle mode. The wake-up event causes a
receive interrupt by setting the RCIF bit. The WUE bit
is cleared after this when a rising edge is seen on RX/
DT. The interrupt condition is then cleared by reading
the RCREG register. Ordinarily, the data in RCREG will
be dummy data and should be discarded.
Following a wake-up event, the module generates an
RCIF interrupt. The interrupt is generated synchro-
nously to the Q clocks in normal operating modes
(Figure 19-7), and asynchronously if the device is in
Sleep mode (Figure 19-8). The interrupt condition is
cleared by reading the RCREG register.
The WUE bit is automatically cleared once a low-to-
high transition is observed on the RX line, following the
wake-up event. At this point, the USART module is in
Idle mode and returns to normal operation. This signals
to the user that the Sync Break event is over.
The fact that the WUE bit has been cleared (or is still
set) and the RCIF flag is set should not be used as an
indicator of the integrity of the data in RCREG. Users
should consider implementing a parallel method in
firmware to verify received data integrity.
To assure that no actual data is lost, check the RCIDL
bit to verify that a receive operation is not in process. If
a receive operation is not occurring, the WUE bit may
then be set just prior to entering the Sleep mode.
19.3.4.1
Special Considerations Using
Auto-Wake-up
Since Auto-Wake-up functions by sensing rising edge
transitions on RX/DT, information with any state
changes before the Stop bit may signal a false end-of-
character and cause data or framing errors. To work
FIGURE 19-7:
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING NORMAL OPERATION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
WUE bit
Auto-Cleared
Bit Set by User
RX/DT Line
RCIF
Cleared due to User Read of RCREG
Note 1: The USART remains in Idle while the WUE bit is set.
FIGURE 19-8:
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Q1
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
WUE bit
Auto-Cleared
Bit Set by User
RX/DT Line
RCIF
Note 1
Cleared due to User Read of RCREG
Sleep Ends
Sleep Command Executed
Note 1: If the wake-up event requires long oscillator warm-up time, the auto-clear of the WUE bit can occur while the stposc signal is still active.
This sequence should not depend on the presence of Q clocks.
2: The USART remains in Idle while the WUE bit is set.
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19.3.5
BREAK CHARACTER SEQUENCE
19.3.5.1
Break and Sync Transmit Sequence
The enhanced USART module has the capability of
sending the special break character sequences that
are required by the LIN bus standard. The break char-
acter transmit consists of a Start bit, followed by 12 ‘0’
bits and a Stop bit. The frame break character is sent
whenever the SENDB and TXEN bits (TXSTA<3> and
TXSTA<5>) are set, while the transmit shift register is
loaded with data. Note that the value of data written to
TXREG will be ignored and all ‘0’s will be transmitted.
The following sequence will send a message frame
header made up of a break, followed by an auto-baud
sync byte. This sequence is typical of a LIN bus master.
1. Configure the USART for the desired mode.
2. Set the TXEN and SENDB bits to setup the
break character.
3. Load the TXREG with a dummy character to
initiate transmission (the value is ignored).
4. Write ‘55h’ to TXREG to load the Sync character
into the transmit FIFO buffer.
The SENDB bit is automatically reset by hardware after
the corresponding Stop bit is sent. This allows the user
to preload the transmit FIFO with the next transmit byte
following the break character (typically, the sync char-
acter in the LIN specification).
5. After the break has been sent, the SENDB bit is
reset by hardware. The sync character now
transmits in the Pre-Configured mode.
When the TXREG becomes empty, as indicated by the
TXIF, the next data byte can be written to TXREG.
Note that the data value written to the TXREG for the
break character is ignored. The write simply serves the
purpose of initiating the proper sequence.
19.3.6
RECEIVING A BREAK CHARACTER
The TRMT bit indicates when the transmit operation is
active or idle, just as it does during normal transmis-
sion. See Figure 19-9 for the timing of the break
character sequence.
The enhanced USART module can receive a break
character in two ways.
The first method forces to configure the baud rate at a
frequency of 9/13 the typical speed. This allows for the
Stop bit transition to be at the correct sampling location
(13 bits for break versus Start bit and 8 data bits for typ-
ical data).
The second method uses the auto-wake-up feature
described in Section 19.3.4 “Auto-Wake-up on
SYNC BREAK Character”. By enabling this feature,
the USART will sample the next two transitions on RX/
DT, cause an RCIF interrupt, and receive the next data
byte followed by another interrupt.
Note that following a break character, the user will
typically want to enable the auto-baud rate detect
feature. For both methods, the user can set the ABD bit
before placing the USART in its Sleep mode.
FIGURE 19-9:
SEND BREAK CHARACTER SEQUENCE
Write to TXREG
Dummy Write
BRG Output
(Shift Clock)
TX (pin)
Start Bit
Bit 0
Bit 1
Break
Bit 11
Stop Bit
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
SENDB Sampled Here
Auto-Cleared
SENDB
(Transmit Shift
Reg. Empty Flag)
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Once the TXREG register transfers the data to the TSR
register (occurs in one TCYCLE), the TXREG is empty
and interrupt bit TXIF (PIR1<4>) is set. The interrupt
19.4 USART Synchronous Master
Mode
The Synchronous Master mode is entered by setting
the CSRC bit (TXSTA<7>). In this mode, the data is
transmitted in a half-duplex manner (i.e., transmission
and reception do not occur at the same time). When
transmitting data, the reception is inhibited and vice
versa. Synchronous mode is entered by setting bit
SYNC (TXSTA<4>). In addition, enable bit SPEN
(RCSTA<7>) is set in order to configure the RC6/TX/
CK/SS and RC7/RX/DT/SDO I/O pins to CK (clock)
and DT (data) lines, respectively.
can be enabled/disabled by setting/clearing enable bit
TXIE (PIE1<4>). Flag bit TXIF will be set, regardless of
the state of enable bit TXIE, and cannot be cleared in
software. It will reset only when new data is loaded into
the TXREG register.
While flag bit TXIF indicates the status of the TXREG
register, another bit, TRMT (TXSTA<1>), shows the
status of the TSR register. TRMT is a read-only bit,
which is set when the TSR is empty. No interrupt logic
is tied to this bit, so the user must poll this bit in order
to determine if the TSR register is empty. The TSR is
not mapped in data memory, so it is not available to the
user.
The Master mode indicates that the processor trans-
mits the master clock on the CK line. Clock polarity is
selected with the SCKP bit (BAUDCTL<5>); setting
SCKP sets the Idle state on CK as high, while clearing
the bit, sets the Idle state low. This option is provided to
support Microwire® devices with this module.
To set up a Synchronous Master Transmission:
1. Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
19.4.1
USART SYNCHRONOUS MASTER
TRANSMISSION
2. Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
The USART transmitter block diagram is shown in
Figure 19-2. The heart of the transmitter is the Transmit
(serial) Shift Register (TSR). The shift register obtains
its data from the read/write transmit buffer register
TXREG. The TXREG register is loaded with data in
software. The TSR register is not loaded until the last
bit has been transmitted from the previous load. As
soon as the last bit is transmitted, the TSR is loaded
with new data from the TXREG (if available).
3. If interrupts are desired, set enable bit TXIE.
4. If 9-bit transmission is desired, set bit TX9.
5. Enable the transmission by setting bit TXEN.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
7. Start transmission by loading data to the TXREG
register.
8. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
FIGURE 19-10:
SYNCHRONOUS TRANSMISSION
Q1 Q2 Q3Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1Q2 Q3 Q4Q1 Q2 Q3 Q4
Q3 Q4 Q1 Q2 Q3Q4 Q1Q2 Q3Q4 Q1 Q2Q3Q4 Q1 Q2Q3 Q4Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
RC7/RX/DT/
SDO pin
bit 0
bit 1
bit 2
bit 7
bit 0
bit 1
Word 2
bit 7
Word 1
RC6/TX/CK/
SS pin
(SCKP = 0)
RC6/TX/CK/
SS pin
(SCKP = 1)
Write to
TXREG Reg
Write Word 1
Write Word 2
TXIF bit
(Interrupt Flag)
TRMT bit
TXEN bit
Note:
'1'
'1'
Sync Master mode, SPBRG = 0, continuous transmission of two 8-bit words.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 237
PIC18F2331/2431/4331/4431
FIGURE 19-11:
SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
RC7/RX/DT/SDO pin
bit0
bit2
bit1
bit6
bit7
RC6/TX/CK/SS pin
Write to
TXREG reg
TXIF bit
TRMT bit
TXEN bit
TABLE 19-7: REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE
—
TMR0IF
INT0IF
RBIF
0000 000x
-000 -000
-000 -000
-000 -000
0000 -00x
0000 0000
0000 0010
-1-1 0-00
0000 0000
0000 0000
0000 000u
-000 -000
-000 -000
-000 -000
0000 -00x
0000 0000
0000 0010
-1-1 0-00
0000 0000
0000 0000
—
—
ADIF
ADIE
ADIP
RX9
RCIF
RCIE
RCIP
SREN
TXIF
TXIE
TXIP
CCP1IF TMR2IF TMR1IF
CCP1IE TMR2IE TMR1IE
CCP1IP TMR2IP TMR1IP
PIE1
—
IPR1
—
—
RCSTA
TXREG
TXSTA
BAUDCTL
SPEN
CREN ADDEN
FERR
OERR
RX9D
USART Transmit Register
CSRC
—
TX9
TXEN
—
SYNC SENDB
SCKP BRG16
BRGH
—
TRMT
WUE
TX9D
RCIDL
ABDEN
SPBRGH Baud Rate Generator Register, High Byte
SPBRG
Baud Rate Generator Register, Low Byte
Legend:
x= unknown, – = unimplemented, read as ‘0’. Shaded cells are not used for Synchronous Master Transmission.
DS39616B-page 238
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
3. Ensure bits CREN and SREN are clear.
4. If interrupts are desired, set enable bit RCIE.
5. If 9-bit reception is desired, set bit RX9.
19.4.2
USART SYNCHRONOUS MASTER
RECEPTION
Once Synchronous mode is selected, reception is
enabled by setting either the Single Receive Enable bit,
SREN (RCSTA<5>), or the Continuous Receive
Enable bit, CREN (RCSTA<4>). Data is sampled on the
RC7/RX/DT/SDO pin on the falling edge of the clock.
6. If a single reception is required, set bit SREN.
For continuous reception, set bit CREN.
7. Interrupt flag bit RCIF will be set when reception
is complete and an interrupt will be generated if
the enable bit RCIE was set.
If enable bit SREN is set, only a single word is received.
If enable bit CREN is set, the reception is continuous
until CREN is cleared. If both bits are set, then CREN
takes precedence.
8. Read the RCSTA register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
9. Read the 8-bit received data by reading the
RCREG register.
To set up a Synchronous Master Reception:
1. Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
10. If any error occurred, clear the error by clearing
bit CREN.
11. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
2. Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
FIGURE 19-12:
SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
RC7/RX/DT/SDO
pin
bit0
bit1
bit2
bit3
bit4
bit5
bit6
bit7
RC6/TX/CK/SS
pin
(SCKP = 0)
RC6/TX/CK/SS
pin
(SCKP = 1)
Write to
bit SREN
SREN bit
CREN bit
‘0’
‘0’
RCIF bit
(Interrupt)
Read
RXREG
Note:
Timing diagram demonstrates Sync Master mode with bit SREN = 1and bit BRGH = 0.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 239
PIC18F2331/2431/4331/4431
TABLE 19-8: REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE
—
TMR0IF INT0IF
RBIF
0000 000x 0000 000u
—
—
ADIF
ADIE
ADIP
RX9
RCIF
RCIE
RCIP
SREN
TXIF
TXIE
TXIP
CCP1IF TMR2IF TMR1IF -000 -000 -000 -000
CCP1IE TMR2IE TMR1IE -000 -000 -000 -000
CCP1IP TMR2IP TMR1IP -111 -111 -111 -111
PIE1
—
IPR1
—
—
RCSTA
RCREG
TXSTA
BAUDCTL
SPEN
CREN ADDEN
FERR
OERR
RX9D
0000 -00x 0000 -00x
0000 0000 0000 0000
0000 0010 0000 0010
-1-1 0-00 -1-1 0-00
0000 0000 0000 0000
0000 0000 0000 0000
USART Receive Register
CSRC
—
TX9
TXEN
—
SYNC
SCKP
SENDB
BRG16
BRGH
—
TRMT
WUE
TX9D
RCIDL
ABDEN
SPBRGH Baud Rate Generator Register, High Byte
SPBRG
Baud Rate Generator Register, Low Byte
Legend:
x= unknown, – = unimplemented, read as ‘0’. Shaded cells are not used for Synchronous Master Reception.
DS39616B-page 240
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
To set up a Synchronous Slave Transmission:
19.5 USART Synchronous Slave Mode
1. Enable the synchronous slave serial port by
setting bits SYNC and SPEN and clearing bit
CSRC.
Synchronous Slave mode is entered by clearing bit
CSRC (TXSTA<7>). This mode differs from the
Synchronous Master mode in that the shift clock is
supplied externally at the RC6/TX/CK/SS pin (instead
of being supplied internally in Master mode). This
allows the device to transfer or receive data while in
any low-power mode.
2. Clear bits CREN and SREN.
3. If interrupts are desired, set enable bit TXIE.
4. If 9-bit transmission is desired, set bit TX9.
5. Enable the transmission by setting enable bit
TXEN.
19.5.1
USART SYNCHRONOUS SLAVE
TRANSMIT
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
The operation of the Synchronous Master and Slave
modes are identical, except in the case of the Sleep
mode.
7. Start transmission by loading data to the TXREG
register.
8. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
If two words are written to the TXREG and then the
SLEEPinstruction is executed, the following will occur:
a) The first word will immediately transfer to the
TSR register and transmit.
b) The second word will remain in TXREG register.
c) Flag bit TXIF will not be set.
d) When the first word has been shifted out of TSR,
the TXREG register will transfer the second
word to the TSR and flag bit TXIF will now be
set.
e) If enable bit TXIE is set, the interrupt will wake
the chip from Sleep. If the global interrupt is
enabled, the program will branch to the interrupt
vector.
TABLE 19-9: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE
—
TMR0IF INT0IF
RBIF
0000 000x 0000 000u
—
—
ADIF
ADIE
ADIP
RX9
RCIF
RCIE
RCIP
SREN
TXIF
TXIE
TXIP
CCP1IF TMR2IF TMR1IF -000 -000 -000 -000
CCP1IE TMR2IE TMR1IE -000 -000 -000 -000
CCP1IP TMR2IP TMR1IP -000 -000 -000 -000
PIE1
—
IPR1
—
—
RCSTA
TXREG
TXSTA
BAUDCTL
SPEN
CREN ADDEN
FERR
OERR
RX9D
0000 -00x 0000 -00x
0000 0000 0000 0000
0000 0010 0000 0010
USART Transmit Register
CSRC
—
TX9
TXEN
—
SYNC SENDB
SCKP BRG16
BRGH
—
TRMT
WUE
TX9D
RCIDL
ABDEN -1-1 0-00 -1-1 0-00
0000 0000 0000 0000
SPBRGH Baud Rate Generator Register, High Byte
SPBRG Baud Rate Generator Register, Low Byte
0000 0000 0000 0000
Legend: x= unknown, – = unimplemented, read as ‘0’. Shaded cells are not used for Synchronous Slave Transmission.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 241
PIC18F2331/2431/4331/4431
To set up a Synchronous Slave Reception:
19.5.2
USART SYNCHRONOUS SLAVE
RECEPTION
1. Enable the synchronous master serial port by
setting bits SYNC and SPEN and clearing bit
CSRC.
The operation of the Synchronous Master and Slave
modes is identical, except in the case of Sleep, or any
Idle mode and bit SREN, which is a “don't care” in
Slave mode.
2. If interrupts are desired, set enable bit RCIE.
3. If 9-bit reception is desired, set bit RX9.
4. To enable reception, set enable bit CREN.
If receive is enabled by setting the CREN bit prior to
entering Sleep or any idle mode, then a word may be
received while in this Low-Power mode. Once the word
is received, the RSR register will transfer the data to the
RCREG register; if the RCIE enable bit is set, the inter-
rupt generated will wake the chip from Low-Power
mode. If the global interrupt is enabled, the program will
branch to the interrupt vector.
5. Flag bit RCIF will be set when reception is com-
plete. An interrupt will be generated if enable bit
RCIE was set.
6. Read the RCSTA register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
7. Read the 8-bit received data by reading the
RCREG register.
8. If any error occurred, clear the error by clearing
bit CREN.
9. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
TABLE 19-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE
—
TMR0IF INT0IF
RBIF
0000 000x 0000 000u
—
—
ADIF
ADIE
ADIP
RX9
RCIF
RCIE
RCIP
SREN
TXIF
TXIE
TXIP
CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
CCP1IP TMR2IP TMR1IP -111 -111 -111 -111
PIE1
—
IPR1
—
—
RCSTA
RCREG
TXSTA
BAUDCTL
SPEN
CREN ADDEN
FERR
OERR
RX9D
0000 -00x 0000 -00x
0000 0000 0000 0000
0000 0010 0000 0010
USART Receive Register
CSRC
—
TX9
TXEN
—
SYNC
SCKP
SENDB
BRG16
BRGH
—
TRMT
WUE
TX9D
RCIDL
ABDEN -1-1 0-00 -1-1 0-00
0000 0000 0000 0000
SPBRGH Baud Rate Generator Register, High Byte
SPBRG Baud Rate Generator Register, Low Byte
0000 0000 0000 0000
Legend: x= unknown, – = unimplemented, read as ‘0’. Shaded cells are not used for Synchronous Slave Reception.
DS39616B-page 242
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
These features lend themselves to many applications
20.0 10-BIT HIGH-SPEED ANALOG-
including motor control, sensor interfacing, data
acquisition and process control. In many cases, these
features will reduce the software overhead associated
with standard A/D modules.
TO-DIGITAL CONVERTER (A/D)
MODULE
The high-speed Analog-to-Digital (A/D) Converter
module allows conversion of an analog signal to a
corresponding 10-bit digital number.
The module has 9 registers:
• A/D Result High Register (ADRESH)
• A/D Result Low Register (ADRESL)
• A/D Control Register 0 (ADCON0)
• A/D Control Register 1 (ADCON1)
• A/D Control Register 2 (ADCON2)
• A/D Control Register 3 (ADCON3)
• A/D Channel Select Register (ADCHS)
• Analog I/O Select Register 0 (ANSEL0)
• Analog I/O Select Register 1 (ANSEL1)
The A/D module supports up to 5 input channels on
PIC18F2X31 devices, and up to 9 channels on the
PIC18F4X31 devices.
This high-speed 10-bit A/D module offers the following
features:
• Up to 200K samples per second
• Two sample and hold inputs for dual-channel
simultaneous sampling
• Selectable simultaneous or sequential sampling
modes
• 4-word data buffer for A/D results
• Selectable data acquisition timing
• Selectable A/D event trigger
• Operation in Sleep using internal oscillator
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 243
PIC18F2331/2431/4331/4431
REGISTER 20-1: ADCON0: A/D CONTROL REGISTER 0
U-0
—
U-0
—
R/W-0
R/W-0
R/W-0
ACMOD1 ACMOD0 GO/DONE ADON
bit 0
R/W-0
R/W-0
R/W-0
ACONV
ACSCH
bit 7
bit 7-6 Unimplemented: Read as ‘0’
bit 5
bit 4
ACONV: Auto-Conversion Continuous Loop or Single-shot Mode Select bit
1= Continuous Loop mode Enabled
0= Single-shot mode Enabled
ACSCH: Auto-Conversion Single or Multi-Channel mode bit
1= Multi-Channel mode Enabled, Single Channel mode Disabled
0= Single Channel mode Enabled, Multi-Channel mode Disabled
bit 3-2 ACMOD: Auto-Conversion mode Sequence Select bits
If ACSCH = 1:
00=Sequential Mode1 (SEQM1). Two samples are taken in sequence:
1st sample: Group A
2nd sample: Group B
01=Sequential Mode2 (SEQM2). Four samples are taken in sequence:
1st sample: Group A
2nd sample: Group B
3rd sample: Group C
4th sample: Group D
10=Simultaneous Mode1 (STNM1). Two samples are taken simultaneously:
1st sample: Group A and Group B
11=Simultaneous Mode2 (STNM2). Two samples are taken simultaneously:
1st sample: Group A and Group B
2nd sample: Group C and Group D
If ACSCH = 0, Auto-Conversion Single Channel Sequence mode enabled:
00=Single Ch Mode1 (SCM1). Group A is taken and converted
01=Single Ch Mode2 (SCM2). Group B is taken and converted
10=Single Ch Mode3 (SCM3). Group C is taken and converted
11=Single Ch Mode4 (SCM4). Group D is taken and converted
Note:
Group A, B, C, D refer to the ADCHS register.
bit 1
GO/DONE: A/D Conversion Status bit
1= A/D conversion cycle in progress. Setting this bit starts the A/D conversion cycle. If Auto-
Conversion Single-shot mode is enabled (ACONV = 0), this bit is automatically cleared by
hardware when the A/D conversion (single or multi-channel depending on ACMOD settings)
has completed. If Auto-Conversion Continuous Loop mode is enabled (ACONV = 1), this bit
remains set after the user/trigger has set it (continuous conversions). It may be cleared
manually by the user to stop the conversions.
0= A/D conversion or multiple conversions completed/not in progress
bit 0
ADON: A/D On bit
1= A/D converter module is enabled (after brief power-up delay, starts continuous sampling)
0= A/D converter module is disabled
Legend:
R = Readable bit
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
-n = Value at Reset
DS39616B-page 244
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
REGISTER 20-2: ADCON1: A/D CONTROL REGISTER 1
R/W-0
R/W-0
U-0
—
R/W-0
R-0
R-0
R-0
R-0
VCFG1
VCFG0
FIFOEN
BFEMT
BFOVFL ADPNT1
ADPNT0
bit 7
bit 0
bit 7-6 VCFG<1:0>: A/D VREF+ and A/D VREF- Source Selection bits
00=VREF+ = AVDD, VREF- = AVSS, (AN2 and AN3 are Analog inputs or Digital I/O)
01=VREF+ = External VREF+, VREF- = AVSS, (AN2 is an Analog input or Digital I/O)
10=VREF+ = AVDD, VREF- = External VREF-, (AN3 is an Analog input or Digital I/O)
11=VREF+ = External VREF-, VREF- = External VREF-
bit 5
bit 4
Unimplemented: Read as ‘0’
FIFOEN: FIFO Buffer Enable bit
1= FIFO is enabled
0= FIFO is disabled
bit 3
bit 2
BFEMT: Buffer Empty bit
1= FIFO is empty
0= FIFO is not empty (at least one of four locations has unread A/D result data)
BFOVFL: Buffer Overflow bit
1= A/D result has overwritten a buffer location that has unread data
0= A/D result has not overflowed
bit 1-0 ADPNT<1:0>: Buffer Read Pointer Locations bits
Designates the location to be read next.
00= Buffer address 0
01= Buffer address 1
10= Buffer address 2
11= Buffer address 3
Legend:
R = Readable bit
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
-n = Value at Reset
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 245
PIC18F2331/2431/4331/4431
REGISTER 20-3: ADCON2 – A/D CONTROL REGISTER 2
R/W-0
ADFM
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
ACQT3
ACQT2
ACQT1
ACQT0
ADCS2
ADCS1
ADCS0
bit 7
bit 0
bit 7
ADFM: A/D Result Format Select bit
1= Right justified
0= Left justified
bit 6-3 ACQT<3:0>: A/D Acquisition Time Select bits
0000= No Delay(1) (Conversion starts immediately when GO/DONE is set)
0001= 2 TAD
0010= 4 TAD
0011= 6 TAD
0100= 8 TAD
0101= 10 TAD
0110= 12 TAD
0111= 16 TAD
1000= 20 TAD
1001= 24 TAD
1010= 28 TAD
1011= 32 TAD
1100= 36 TAD
1101= 40 TAD
1110= 48 TAD
1111= 64 TAD
bit 2-0 ADCS<2:0>: A/D Conversion Clock Select bits
000 = FOSC/2
001 = FOSC/8
010 = FOSC/32
011 = FRC/4(2)
100 = FOSC/4
101 = FOSC/16
110 = FOSC/64
111 = FRC (Internal A/D RC Oscillator)
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before sampling/
conversion starts.
2: Due to an increased frequency of the internal A/D RC oscillator, FRC/4 provides clock
frequencies compatible with previous A/D modules.
3: In sequential mode TACQ should be 12 TAD or greater.
Legend:
R = Readable bit
-n = Value at Reset
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
DS39616B-page 246
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
REGISTER 20-4: ADCON3: A/D CONTROL REGISTER 3
R/W-0
R/W-0
U-0
—
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
ADRS1
ADRS0
SSRC4
SSRC3
SSRC2
SSRC1
SSRC0
bit 7
bit 0
bit 7-6 ADRS<1:0>: A/D Result Buffer Depth Interrupt Select Control bits for Continuous Loop mode
The ADRS bits are ignored in Single-shot mode.
00=Interrupt is generated when each word is written to the buffer
01=Interrupt is generated when the 2nd & 4th words are written to the buffer
10=Interrupt is generated when the 4th word is written to the buffer
11=Unimplemented
bit 5
Unimplemented: Read as ‘0’
bit 4:0 SSRCx<4:0>: A/D Trigger Source Select bits
00000=All triggers disabled
xxxx1=External interrupt RC3/INT0 starts A/D sequence
xxx1x=Timer5 starts A/D sequence
xx1xx=Input Capture 1 (IC1) starts A/D sequence
x1xxx=CCP2 compare match starts A/D sequence
1xxxx=Power Control PWM module rising edge starts A/D sequence
Note 1: SSRCx<4:0> bits can be set such that any of the triggers will start conversion (e.g.
SSRCx<4:0)> = 00101, will trigger the A/D conversion sequence when RC3/INT0
or Input Capture 1 event occurs).
Legend:
R = Readable bit
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
-n = Value at Reset
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 247
PIC18F2331/2431/4331/4431
REGISTER 20-5: ADCHS: A/D CHANNEL SELECT REGISTER
R/W-0
GDSEL1
bit 7
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
GDSEL0
GBSEL1
GBSEL0 GCSEL1 GCSEL0 GASEL1 GASEL0
bit 0
bit 7-6 GDSEL1:GDSEL0: Group D Select bits
S/H-2 positive input
00=AN3
01=AN7(1)
1x=Reserved
bit 5-4 GBSEL1:GBSEL0: Group B Select bits
S/H-2 positive input
00=AN1
01=AN5(1)
1x=Reserved
bit 3-2 GCSEL1:GCSEL0: Group C Select bits
S/H-1 positive input
00=AN2
01=AN6(1)
1x=Reserved
bit 1-0 GASEL1:GASEL0: Group A Select bits
S/H-1 positive input
00=AN0
01=AN4
10=AN8(1)
11=Reserved
Note 1: AN5 through AN8 are available only in PIC18F4X31 devices.
Legend:
R = Readable bit
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
-n = Value at Reset
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REGISTER 20-6: ANSEL0: ANALOG SELECT REGISTER 0(1)
R/W-1
ANS7(2)
R/W-1
ANS6(2)
R/W-1
ANS5(2)
R/W-1
ANS4
R/W-1
ANS3
R/W-1
ANS2
R/W-1
ANS1
R/W-1
ANS0
bit 7
bit 0
bit 7-0 ANS<7:0>: Analog Input Function Select bits
Correspond to pins AN<7:0>
1= Analog Input
0= Digital I/O
Note 1: Setting a pin to an analog input disables the digital input buffer. The corresponding
TRIS bit should be set for an input and cleared for an output (analog or digital). The
ANSx bits directly correspond to the ANx pins (e.g., ANS0 = AN0, ANS1 = AN1, etc.)
Unused ANSx bits are to be read as ‘0’.
2: ANS7 through ANS5 are available only on PIC18F4X31 devices.
Legend:
R = Readable bit
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
-n = Value at Reset
REGISTER 20-7: ANSEL1: ANALOG SELECT REGISTER 1(1)
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
R/W-1
ANS8(2)
bit 15
bit 8
bit 15-9 Unimplemented: Read as ‘0’
bit 8
ANS8: Analog Input Function Select bit
1= Analog Input
0= Digital I/O
Note 1: Setting a pin to an analog input disables the digital input buffer. The corresponding
TRIS bit should be set for an input and cleared for an output (analog or digital). The
ANSx bits directly correspond to the ANx pins (e.g., ANS8 = AN8, ANS9 = AN9, etc.)
Unused ANSx bits are to be read as ‘0’.
2: ANS8 is available only on PIC18F4X31 devices.
Legend:
R = Readable bit
W = Writable bit
‘1’ = bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared x = bit is unknown
-n = Value at Reset
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Preliminary
DS39616B-page 249
PIC18F2331/2431/4331/4431
The A/D channels are grouped into four sets of 2 or 3
channels. For the PIC18F2X31 devices, AN0 and AN4
are in Group A, AN1 is in Group B, AN2 is in Group C
and AN3 is in Group D. For the PIC18F4X31 devices,
AN0, AN4 and AN8 are in Group A, AN1 and AN5 are
in Group B, AN2 and AN6 are in Group C and AN3 and
AN7 are in Group D. The selected channel in each
group is selected by configuring the A/D Channel
Select Register, ADCHS.
The A/D converter has a unique feature of being able
to operate while the device is in Sleep mode. To
operate in Sleep, the A/D conversion clock must be
derived from the A/D’s internal RC oscillator.
A device Reset forces all registers to their Reset state.
This forces the A/D module to be turned off and any
conversion in progress is aborted.
Each port pin associated with the A/D converter can
individually be configured as an analog input or digital
I/O using the ANSEL0 and ANSEL1 registers. The
ADRESH and ADRESL registers contain the value in
the result buffer pointed to by ADPNT<1:0>
(ADCON1<1:0>). The result buffer is a 4-deep circular
buffer that has an empty status bit, BEMT
(ADCON1<3>), and an overflow status bit, BOVFL
(ADCON1<2>).
The analog voltage reference is software selectable to
either the device’s positive and negative analog supply
voltage (AVDD and AVSS), or the voltage level on the
RA3/AN3/VREF+/CAP2/QEA and RA2/AN2/VREF-/
CAP1/INDX, or some combination of supply and
external sources. Register ADCON1 controls the
voltage reference settings.
FIGURE 20-1:
A/D BLOCK DIAGRAM
VCFG<1:0>
AVDD
AVSS
VREF+
VREF-
VREFL
VREFH
ADC
AN0
AN4
AN8(1)
ADRESH, ADRESL
MUX
10
Analog
Mux
AN2/VREF-
AN6(1)
ADPNT<1:0>
00
1
2
3
S/H-1
+
01
10
11
ACMOD, GxSEL<1:0>
S/H
-
4
4x10-bit FIFO
AVSS
ACONV
ACSCM
ACMOD
AN1
AN5(1)
Analog
Mux
AN3/VREF+
AN7(1)
S/H-2
+
S/H
-
ACMOD, GxSEL<1:0>
AVSS
Seq.
Cntrl.
Note 1: AN5 through AN8 are available only on PIC18F4X31 devices.
DS39616B-page 250
Preliminary
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ACMOD<1:0> bits (ADCON0<3:2>). In addition, the
20.1 Configuring the A/D Converter
A/D channels are divided into four groups as defined
in the ADCHS register. Table 20-1 shows the
sequence configurations as controlled by ACSCH and
ACMOD<1:0>.
The A/D converter has two types of conversion, two
modes of operation and eight different sequencing
modes. These features are controlled by the ACONV
bit (ADCON0<5>), ACSH bit (ADCON0<4>) and
TABLE 20-1: AUTO-CONVERSION SEQUENCE CONFIGURATIONS
Mode
ACSCH
ACMOD
Description
Multi-Channel Sequential Mode1
(SEQM1)
1
00
Group A and B are sampled and converted
sequentially
Multi-Channel Sequential Mode2
(SEQM2)
1
1
1
01
10
11
Group A, B, C and D are sampled and converted
sequentially
Multi-Channel Simultaneous Mode1
(STNM1)
Group A and B are sampled simultaneously and
converted sequentially
Multi-Channel Simultaneous Mode2
(STNM2)
Group A and B are sampled simultaneously, then
converted sequentially. Then, Group C and D are
sampled simultaneously, then converted
sequentially.
Single Channel Mode1 (SCM1)
Single Channel Mode2 (SCM2)
Single Channel Mode3 (SCM3)
Single Channel Mode4 (SCM4)
0
0
0
0
00
01
10
11
Group A is sampled and converted
Group B is sampled and converted
Group C is sampled and converted
Group D is sampled and converted
20.1.1
CONVERSION TYPE
20.1.2
CONVERSION MODE
Two types of conversions exist in the high-speed 10-bit
A/D converter module that are selected using the
The ACSCH bit (ADCON0<4>) controls how many
channels are used in the configured sequence. When
clear, the A/D is configured for single channel conver-
sion and will convert the group selected by
ACMOD<1:0> and channel selected by GxSEL<1:0>
(ADCHS). When ACSCH = ‘1’, the A/D is configured for
multiple channel conversion and the sequence is
defined by ACMOD<1:0>.
ACONV bit. Single-shot mode allows
a single
conversion or sequence to be when ACONV = ‘0’. At
the end of the sequence, the GO/DONE bit will be
automatically cleared and the interrupt flag, ADIF, will
be set. When using Single-shot mode and configured
for Simultaneous mode, STNM2, acquisition time must
be used to ensure proper conversion of the analog
input signals.
Continuous Loop mode allows the defined sequence to
be executed in a continuous loop when ACONV = ‘1’.
In this mode, either the user can trigger the start of con-
version by setting the GO/DONE bit or one of the A/D
triggers can start the conversion. The interrupt flag
ADIF is set based on the configuration of the bits
ADRS<1:0> (ADCON3<7:6>). In simultaneous modes,
STNM1 and STNM2, acquisition time must be config-
ured to ensure proper conversion of the analog input
signals.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 251
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20.1.3
CONVERSION SEQUENCING
20.1.5
A/D MODULE INITIALIZATION
STEPS
The ACMOD<1:0> bits control the sequencing of the
A/D conversions. When ACSCH = 0, the A/D is
configured to sample and convert a single channel.
The ACMOD bits select which group to perform the
conversions and the GxSEL<1:0> bits select which
channel in the group is to be converted. If Single-shot
mode is enabled, the A/D interrupt flag will be set after
the channel is converted. If Continuous Loop mode is
enabled, the A/D interrupt flag will be set according to
the ADRS<1:0> bits.
The following steps should be followed to initialize the
A/D module:
1. Configure the A/D module:
a) Configure analog pins, voltage reference
and digital I/O
b) Select A/D input channels
c) Select A/D Auto-conversion mode
(Single-shot or Continuous Loop)
d) Select A/D conversion clock
e) Select A/D conversion trigger
2. Configure A/D interrupt (if required):
a) Set GIE bit
When ACSHC = 1, multiple channel sequencing is
enabled and two sub-modes can be selected. The first
mode is Sequential mode with two settings. The first
setting is called SEQM1 and first samples and converts
the selected Group A channel and then samples and
converts the selected Group B channel. The second
mode is called SEQM2, and it samples and converts a
Group A channel, Group B channel, Group C channel
and finally a Group D channel.
b) Set PEIE bit
c) Set ADIE bit
d) Clear ADIF bit
e) Select A/D trigger setting
f) Select A/D interrupt priority
3. Turn On ADC:
The second multiple channel sequencing sub-mode is
Simultaneous Sampling mode. In this mode, there are
also two settings. The first setting is called STNM1 and
uses the two sample and hold circuits on the A/D
module. The selected Group A and B channels are
simultaneously sampled and then the Group A channel
is converted followed by the conversion of the Group B
channel. The second setting is called STNM2 and
starts the same as STNM1 but follows it with a
simultaneous sample of Group C and D channels. The
A/D module will then convert the Group C channel
followed by the Group D channel.
a) Set ADON bit in ADCON0 register
b) Wait the required power-up setup time,
about 5-10 µs
4. Start sample/conversion sequence:
a) Sample for a minimum of 2TAD and start
conversion by setting the GO/DONE bit.
The GO/DONE bit is set by the user in
software or by the module if initiated by a
trigger.
b) If TACQ is assigned a value (multiple of TAD),
then setting the GO/DONE bit starts a
sample period of the TACQ value, then starts
a conversion.
20.1.4
TRIGGERING A/D CONVERSIONS
The PIC18F2331/2431/4331/4431 devices are capable
of triggering conversions from many different sources.
The same method used by all other microcontrollers of
setting the GO/DONE bit still works. The other trigger
sources are:
5. Wait for A/D conversion/conversions to
complete using one of the following options:
a) Poll for the GO/DONE bit to be cleared if in
Single-shot mode.
• RC3/INT0 pin
b) Wait for the A/D interrupt flag (ADIF) to be
set.
• Timer5 Overflow
• Input Capture 1 (IC1)
• CCP2 Compare Match
• Power Control PWM rising edge
c) Poll for the BFEMT bit to be cleared to
signify that at least the first conversion has
completed.
These triggers are enabled using the SSRC<4:0> bits
(ADCON3<4:0>). Any combination of the five sources
can trigger a conversion by simply setting the corre-
sponding bit in ADCON3. When the trigger occurs, the
GO/DONE bit is automatically set by the hardware and
then cleared once the conversion completes.
6. Read A/D results, clear ADIF flag, reconfigure
trigger.
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20.2 A/D Result Buffer
20.3 A/D Acquisition Requirements
The A/D module has a 4-level result buffer with an
address range of 0 to 3, enabled by setting the FIFOEN
bit in the ADCON1 register. This buffer is implemented
in a circular fashion where the A/D result is stored in
one location and the address is incremented. If the
address is greater than 3, the pointer is wrapped back
around to 0. The result buffer has a buffer empty flag,
BEMT, indicating when any data is in the buffer. It also
has an overflow flag, BOVFL, which indicates when a
new sample has overwritten a location that was not
previously read.
For the A/D converter to meet its specified accuracy,
the charge holding capacitor (CHOLD) must be allowed
to fully charge to the input channel voltage level. The
analog input model is shown in Figure 20-2. The
source impedance (RS) and the internal sampling
switch (RSS) impedance directly affect the time
required to charge the capacitor CHOLD. The sampling
switch (RSS) impedance varies over the device voltage
(VDD). The source impedance affects the offset voltage
at the analog input (due to pin leakage current). The
maximum recommended impedance for analog
sources is 2.5 kΩ. After the analog input channel is
selected (changed), the channel must be sampled for
at least the minimum acquisition time before starting a
conversion.
Associated with the buffer is a pointer to the address for
the next read operation. The ADPNT<1:0> bits
configure the address for the next read operation.
These bits are read-only.
Note:
When the conversion is started, the
holding capacitor is disconnected from the
input pin.
The Result Buffer also has a configurable interrupt
trigger level that is configured by the ADRS<1:0> bits.
The user has three selections: interrupt flag set on
every write to the buffer, interrupt on every second write
to the buffer, or interrupt on every fourth write to the
buffer. ADPNT<1:0> is reset to ‘00’ every time a
conversion sequence is started (either by setting the
GO/DONE bit, or on a trigger).
To calculate the minimum acquisition time,
Equation 20-1 may be used. This equation assumes
that 1/2 LSb error is used (1024 steps for the A/D). The
1/2 LSb error is the maximum error allowed for the A/D
to meet its specified resolution.
Note:
When right justified, reading ADRESL
increments ADPNT. When left justified,
reading ADRESH increments ADPNT.
Example 20-1 shows the calculation of the minimum
required acquisition time TACQ. In this case, the
converter module is fully powered up at the outset and
therefore the amplifier settling time, TAMP, is negligible.
This calculation is based on the following application
system assumptions:
CHOLD
Rs
Conversion Error
VDD
Temperature
VHOLD
=
=
≤
=
=
=
9 pF
100 Ω
1/2 LSb
5V → Rss = 6 kΩ
50°C (system max.)
0V @ time = 0
EQUATION 20-1: ACQUISITION TIME
TACQ
=
=
Amplifier Settling Time + Holding Capacitor Charging Time + Temperature Coefficient
TAMP + TC + TCOFF
EQUATION 20-2: MINIMUM A/D HOLDING CAPACITOR CHARGING TIME
VHOLD
or
TC
=
=
(VREF – (VREF/2048)) • (1 – e(-Tc/CHOLD(RIC + RSS + RS))
)
-(CHOLD)(RIC + RSS + RS) ln(1/2048)
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 253
PIC18F2331/2431/4331/4431
EXAMPLE 20-1:
CALCULATING THE MINIMUM REQUIRED ACQUISITION TIME
TACQ
TAMP
TCOFF
=
=
=
TAMP + TC + TCOFF
negligible
(Temp – 25°C)(0.005 µs/°C)
(50°C – 25°C)(0.005 µs/°C) = .13 µs
Temperature coefficient is only required for temperatures > 25°C. Below 25°C, TCOFF = 0 µs.
TC
–
-(CHOLD) (RIC + RSS + RS) ln(1/2047) µs
-(9 pF) (1 kΩ + 6 kΩ + 100 Ω) ln(0.0004883) µs = .49 µs + .13 µs = .62 µs
TACQ
=
0 + .62 µs + .13 µs = .75 µs
Note:
If the converter module has been in Sleep mode, TAMP is 2.0 µs from the time the part exits Sleep mode.
FIGURE 20-2:
ANALOG INPUT MODEL
VDD
Sampling
Switch
VT = 0.6V
ANx
SS
RIC ≤ 1k
RSS
Rs
CPIN
VAIN
I leakage
± 500 nA
CHOLD = 9 pF
VT = 0.6V
5 pF
VSS
Legend: CPIN
= input capacitance
= threshold voltage
6V
5V
VDD 4V
VT
I LEAKAGE = leakage current at the pin due to
various junctions
3V
RIC
= interconnect resistance
= sampling switch
2V
SS
CHOLD
RSS
= sample/hold capacitance (from DAC)
= sampling switch resistance
5
6
7
8 9 10 11
Sampling Switch (kΩ)
Note:
For VDD < 2.7V and temperatures below 0ºC, VAIN should be restricted to range: VAIN < VDD/2.
DS39616B-page 254
Preliminary
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PIC18F2331/2431/4331/4431
20.4 A/D Voltage References
20.6 Selecting the A/D Conversion
Clock
If external voltage references are used instead of the
internal AVDD and AVSS sources, the source
impedance of the VREF+ and VREF- voltage sources
must be considered. During acquisition, currents
supplied by these sources are insignificant. However,
during conversion, the A/D module sinks and sources
current through the reference sources.
The A/D conversion time per bit is defined as TAD. The
A/D conversion requires 12 TAD per 10-bit conversion.
The source of the A/D conversion clock is software
selectable. There are eight possible options for TAD:
• 2 TOSC
• 4 TOSC
In order to maintain the A/D accuracy, the voltage
reference source impedances should be kept low to
reduce voltage changes. These voltage changes occur
as reference currents flow through the reference
source impedance.
• 8 TOSC
• 16 TOSC
• 32 TOSC
• 64 TOSC
• Internal RC Oscillator
• Internal RC Oscillator/4
Note:
When using external references, the
source impedance of the external voltage
references must be less than 75Ω in order
to achieve the specified ADC resolution. A
higher reference source impedance will
increase the ADC offset and gain errors.
Resistive voltage dividers will not provide
a low enough source impedance. To
ensure the best possible ADC perfor-
mance, external VREF inputs should be
buffered with an op-amp or other low
impedance circuit.
For correct A/D conversions, the A/D conversion clock
(TAD) must be as short as possible, but greater than the
minimum TAD (approximately 416 µs, see parameter
130 for more information).
Table 20-2 shows the resultant TAD times derived from
the device operating frequencies and the A/D clock
source selected.
20.5 Selecting and Configuring
Automatic Acquisition Time
The ADCON2 register allows the user to select an
acquisition time that occurs each time an A/D conver-
sion is triggered.
When the GO/DONE bit is set, sampling is stopped and
a conversion begins. The user is responsible for
ensuring the required acquisition time has passed
between selecting the desired input channel and the
start of conversion. This occurs when the
ACQT3:ACQT0 bits (ADCON2<6:3>) remain in their
Reset state (‘0000’).
If desired, the ACQT bits can be set to select a
programmable acquisition time for the A/D module.
When triggered, the A/D module continues to sample
the input for the selected acquisition time, then
automatically begins
a
conversion. Since the
acquisition time is programmed, there may be no need
to wait for an acquisition time between selecting a
channel and triggering the A/D. If an acquisition time is
programmed, there is nothing to indicate if the
acquisition time has ended, or if the conversion has
begun.
2003 Microchip Technology Inc.
Preliminary
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TABLE 20-2: TAD vs. DEVICE OPERATING FREQUENCIES
AD Clock Source (TAD)
Maximum Device Frequency
Operation
ADCS2:ADCS0
PIC18FXX31
PIC18LFXX31(4)
2 TOSC
4 TOSC
8 TOSC
16 TOSC
32 TOSC
64 TOSC
RC/4(3)
RC(3)
000
100
001
101
010
110
011
111
4.8 MHz
9.6 MHz
666 kHz
1.33 MHz
2.66 MHz
5.33 MHz
10.65 MHz
21.33 MHz
1.00 MHz(2)
4.0 MHz(2)
19.2 MHz
38.4 MHz
40.0 MHz
40.0 MHz
1.00 MHz(1)
4.0 MHz(2)
Note 1: The RC source has a typical TAD time of 2-6 µs.
2: The RC source has a typical TAD time of 0.5-1.5 µs.
3: For device frequencies above 1 MHz, the device must be in Sleep for the entire conversion or the A/D
accuracy may be out of specification, unless in Single-shot mode.
4: Low-power devices only.
20.7 Operation in Power-Managed
Note:
The A/D can operate in Sleep mode only
when configured for Single-shot opera-
tion. If the part is in Sleep mode, and it is
possible for a source other than the A/D
module to wake the part, the user must
poll ADCON<GO/DONE> to ensure it is
clear before reading the result.
Modes
The selection of the automatic acquisition time and
A/D conversion clock is determined in part by the
clock source and frequency while in a power-man-
aged mode.
If the A/D is expected to operate while the device is in
a power-managed mode, the ACQT3:ACQT0 and
ADCS2:ADCS0 bits in ADCON2 should be updated in
accordance with the power-managed mode clock that
will be used. After the power-managed mode is entered
(either of the power-managed run modes), an A/D
acquisition or conversion may be started. Once an
acquisition or conversion is started, the device should
continue to be clocked by the same power-managed
mode clock source until the conversion has been com-
pleted. If desired, the device may be placed into the
corresponding power-managed Idle mode during the
conversion.
20.8 Configuring Analog Port Pins
The ANSEL0, ANSEL1, TRISA and TRISE registers all
configure the A/D port pins. The port pins needed as
analog inputs must have their corresponding TRIS bits
set (input). If the TRIS bit is cleared (output), the digital
output level (VOH or VOL) will be converted.
The A/D operation is independent of the state of the
ANSEL0, ANSEL1 and the TRIS bits.
Note 1: When reading the Port register, all pins
configured as analog input channels will
read as cleared (a low level). Pins
configured as digital inputs will convert an
analog input. Analog levels on a digitally
configured input will be accurately
converted.
If the power-managed mode clock frequency is less
than 1 MHz, the A/D RC clock source should be
selected.
Operation in Sleep mode requires the A/D RC clock to
be selected. If bits ACQT3:ACQT0 are set to ‘0000’,
and a conversion is started, the conversion will be
delayed one instruction cycle to allow execution of the
SLEEPinstruction and entry to Sleep mode. The IDLEN
and SCS bits in the OSCCON register must have
already been cleared prior to starting the conversion.
2: Analog levels on any pin defined as a
digital input may cause the digital input
buffer to consume current out of the
device’s specification limits.
DS39616B-page 256
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
Clearing the GO/DONE bit during a conversion will
abort the current conversion. The resulting buffer loca-
tion will contain the partially completed A/D conversion
sample. This will not set the ADIF flag, therefore, the
user must read the buffer location before a conversion
sequence overwrites it.
20.9 A/D Conversions
Figure 20-3 shows the operation of the A/D converter
after the GO bit has been set and the ACQT2:ACQT0
bits are cleared. A conversion is started after the follow-
ing instruction to allow entry into Sleep mode before the
conversion begins. The internal A/D RC oscillator must
be selected to perform a conversion in Sleep.
After the A/D conversion is completed or aborted, a
2 TAD wait is required before the next acquisition can
be started. After this wait, acquisition on the selected
channel is automatically started.
Figure 20-4 shows the operation of the A/D converter
after the GO bit has been set and the ACQT3:ACQT0
bits are set to ‘010’, and selecting a 4 TAD acquisition
time before the conversion starts.
Note: The GO/DONE bit should NOT be set in
the same instruction that turns on the A/D.
FIGURE 20-3:
A/D CONVERSION TAD CYCLES (ACQT<2:0> = 000, TACQ = 0)
GO bit is set,
and holding
cap is
TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD9 TAD10 TAD11
b6
b9
b8
b5
b4
b3
b2
b7
b0
b1
disconnected
from analog
input
Conversion Starts
Go bit cleared on the rising edge of Q1 after the first Q3
following TAD11(1), and result buffer is loaded.
Note 1: Conversion time is a minimum of 11 TAD + 2 TCY, and a maximum of 11 TAD + 6 TCY.
FIGURE 20-4:
A/D CONVERSION TAD CYCLES (ACQT<3:0> = 0010, TACQ = 4 TAD)
TACQT Cycles
TAD Cycles
1
2
3
4
TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD9 TAD10 TAD11
b6
b9
Conversion Starts
(Holding capacitor is disconnected)
b8
b5
b4
b3
b2
b7
b0
b1
Automatic
Acquisition
Time
A/D triggered
Go bit cleared on the rising edge of Q1 after the first Q3
following TAD11(1) and result buffer is loaded.
Note 1: In continuous modes, next conversion starts at the end of TAD12.
2003 Microchip Technology Inc.
Preliminary
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A/D Format Select bit (ADFM) controls this justification.
Figure 20-5 shows the operation of the A/D result
justification. The extra bits are loaded with ‘0’s. When
an A/D result will not overwrite these locations (A/D
disable), these registers may be used as two general
purpose 8-bit registers.
20.9.1
A/D RESULT REGISTER
The ADRESH:ADRESL register pair is the location
where the 10-bit A/D result is loaded at the completion
of the A/D conversion. This register pair is 16-bits wide.
The A/D module gives the flexibility to left- or right-
justify the 10-bit result in the 16-bit result register. The
FIGURE 20-5:
A/D RESULT JUSTIFICATION
10-bit Result
ADFM = 0
ADFM = 1
0
7
7
2 1 0 7
0 7 6 5
0
0000 00
0000 00
ADRESH
ADRESL
ADRESH
ADRESL
10-bit Result
10-bit Result
Left Justified
Right Justified
EQUATION 20-3: CONVERSION TIME FOR MULTICHANNEL MODES
Sequential Mode:
T = (TACQ)A + (TCON)A + [(TACQ)B - 12TAD] + (TCON)B + [(TACQ)C - 12TAD] + (TCON)C + [(TACQ)D - 12TAD] + (TCON)D
Simultaneous Mode:
T = TACQ + (TCON)A + (TCON)B + TACQ + (TCON)C + (TCON)D
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TABLE 20-3: SUMMARY OF A/D REGISTERS
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
GIE/
GIEH
PEIE/
GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000 0000 0000
PIR1
PIE1
IPR1
PIR2
PIE2
IPR2
PSPIF
PSPIE
ADIF
ADIE
ADIP
CMIF
CMIE
CMIP
RCIF
RCIE
RCIP
—
TXIF
TXIE
TXIP
EEIF
EEIE
EEIP
SSPIF
SSPIE
SSPIP
BCLIF
BCLIE
BCLIP
CCP1IF
CCP1IE
CCP1IP
LVDIF
TMR2IF
TMR2IE
TMR2IP
TMR3IF
TMR3IE
TMR3IP
TMR1IF 0000 0000 0000 0000
TMR1IE 0000 0000 0000 0000
TMR1IP 1111 1111 1111 1111
CCP2IF 00-0 0000 00-0 0000
CCP2IE 00-0 0000 00-0 0000
CCP2IP 11-1 1111 11-1 1111
xxxx xxxx uuuu uuuu
PSPIP
OSCFIF
OSCFIE
OSCFIP
—
LVDIE
—
LVDIP
ADRESH A/D Result Register High Byte
ADRESL A/D Result Register Low Byte
xxxx xxxx uuuu uuuu
ADCON0
ADCON1
ADCON2
ADCON3
ADCHS
ANSEL0
ANSEL1
PORTA
—
—
ACONV ACMOD1 ACMOD0 CHS0 GO/DONE ADON
00-1 0000 00-1 0000
VCFG1
ADFM
ADRS1
VCFG0
ACQT3
ADRS0
—
ACQT2
—
FIFOEN
ACQT1
SSRC4
BFEMT BFOVFL ADPNT1 ADPNT0 --00 qqqq --00 qqqq
ACQT0
SSRC3
ADCS2
SSRC2
ADCS1
SSRC1
ADCS0 0-00 0000 0-00 0000
SSRC0 00-0 0000 00-0 0000
GDSEL1 GDSEL0 GBSEL1 GBSEL0 GCSEL1 GCSEL0 GASEL1 GASEL0 0000 0000 0000 0000
(6)
(6)
(6)
ANS7
—
ANS6
—
ANS5
—
ANS4
—
ANS3
—
ANS2
—
ANS1
—
ANS0
1111 1111 1111 1111
---- ---1 ---- ---1
--0x 0000 --0u 0000
--11 1111 --11 1111
---- xxxx ---- uuuu
0000 -111 0000 -111
---- -xxx ---- -uuu
(5)
ANS8
RA0
(4)
(4)
RA7
RA6
RA5
RA4
RA3
RA2
RA1
(4)
(4)
TRISA7
—
TRISA6
—
Data Direction Control Register for PORTA
TRISA
(2)
(1)
(4)
PORTE
—
IBOV
—
—
PSPMODE
—
RE3
—
Read PORTE Pins, Write Late
PORTE Data Direction
(3)
TRISE
IBF
OBE
—
(3)
LATE
—
PORTE Output Data Latch
Legend:
x= unknown, u= unchanged, – = unimplemented, read as ‘0’, q = value depends on condition.
Shaded cells are not used for A/D conversion.
Note 1: RE3 port bit is available only as an input pin when MCLRE bit in configuration register is ‘0’.
2: This register is not implemented on PIC18F2X31 devices.
3: These bits are not implemented on PIC18F2X31 devices.
4: These pins may be configured as port pins depending on the Oscillator mode selected.
5: ANS5 through ANS8 are available only on the PIC18F4X31 devices.
6: Not available on 28-pin devices.
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NOTES:
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until the device voltage is no longer in valid operating
range, to shut down the system. Voltage point VB is the
minimum valid operating voltage specification. This
occurs at time TB. The difference TB – TA is the total
time for shutdown.
21.0 LOW-VOLTAGE DETECT
In many applications, the ability to determine if the
device voltage (VDD) is below a specified voltage level
is a desirable feature. A window of operation for the
application can be created, where the application
software can do “housekeeping tasks” before the
device voltage exits the valid operating range. This can
be done using the Low-Voltage Detect module (LVD).
The block diagram for the LVD module is shown in
Figure 21-2. A comparator uses an internally gener-
ated reference voltage as the set point. When the
selected tap output of the device voltage crosses the
set point (is lower than), the LVDIF bit is set.
This module is a software programmable circuitry,
where a device voltage trip point can be specified.
When the voltage of the device becomes lower then the
specified point, an interrupt flag is set. If the interrupt is
enabled, the program execution will branch to the
interrupt vector address and the software can then
respond to that interrupt source.
Each node in the resistor divider represents a “trip
point” voltage. The “trip point” voltage is the minimum
supply voltage level at which the device can operate
before the LVD module asserts an interrupt. When the
supply voltage is equal to the trip point, the voltage
tapped off of the resistor array is equal to the 1.2V
internal reference voltage generated by the voltage
reference module. The comparator then generates an
interrupt signal setting the LVDIF bit. This voltage is
software programmable to any one of 16 values (see
Figure 21-2). The trip point is selected by programming
the LVDL3:LVDL0 bits (LVDCON<3:0>).
The Low-Voltage Detect circuitry is completely under
software control. This allows the circuitry to be turned
off by the software, which minimizes the current
consumption for the device.
Figure 21-1 shows a possible application voltage curve
(typically for batteries). Over time, the device voltage
decreases. When the device voltage equals voltage VA,
the LVD logic generates an interrupt. This occurs at
time TA. The application software then has the time,
FIGURE 21-1:
TYPICAL LOW-VOLTAGE DETECT APPLICATION
VA
VB
Legend:
VA = LVD trip point
VB = Minimum valid device
operating voltage
TB
TA
Time
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FIGURE 21-2:
LOW-VOLTAGE DETECT (LVD) BLOCK DIAGRAM
VDD
LVDIN
LVD Control
Register
LVDIF
Internally Generated
LVDEN
Reference Voltage
1.2V
The LVD module has an additional feature that allows
the user to supply the sense voltage to the module
from an external source. This mode is enabled when
bits LVDL3:LVDL0 are set to ‘1111’. In this state, the
comparator input is multiplexed from the external input
pin, LVDIN (Figure 21-3). This gives users flexibility,
because it allows them to configure the low-voltage
detect interrupt to occur at any voltage in the valid
operating range.
FIGURE 21-3:
LOW-VOLTAGE DETECT (LVD) WITH EXTERNAL INPUT BLOCK DIAGRAM
VDD
VDD
LVD Control
Register
LVDIN
LVDEN
Externally Generated
Trip Point
LVD
VxEN
BODEN
EN
BGAP
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21.1 Control Register
The Low-Voltage Detect Control register controls the
operation of the Low-Voltage Detect circuitry.
REGISTER 21-1: LVDCON REGISTER
U-0
—
U-0
—
R-0
R/W-0
R/W-0
LVDL3
R/W-1
LVDL2
R/W-0
LVDL1
R/W-1
LVDL0
IRVST
LVDEN
bit 7
bit 0
bit 7-6 Unimplemented: Read as ‘0’
bit 5
bit 4
IRVST: Internal Reference Voltage Stable Flag bit
1= Indicates that the Low-Voltage Detect logic will generate the interrupt flag at the
specified voltage range
0= Indicates that the Low-Voltage Detect logic will not generate the interrupt flag at the
specified voltage range and the LVD interrupt should not be enabled
LVDEN: Low-Voltage Detect Power Enable bit
1= Enables LVD, powers up LVD circuit
0= Disables LVD, powers down LVD circuit
bit 3-0 LVDL3:LVDL0: Low-Voltage Detection Limit bits
1111= External analog input is used (input comes from the LVDIN pin)
1110= 4.23V - 4.96V
1101= 3.93V - 4.62V
1100= 3.75V - 4.40V
1011= 3.56V - 4.18V
1010= 3.38V - 3.96V
1001= 3.29V - 3.86V
1000= 3.09V - 3.63V
0111= 2.82V - 3.31V
0110= 2.64V - 3.10V
0101= 2.55V - 2.99V
0100= 2.35V - 2.76V
0011= 2.26V - 2.65V
0010= 2.08V - 2.44V
0001= Reserved
0000= Reserved
Note:
LVDL3:LVDL0 modes which result in a trip point below the valid operating voltage
of the device are not tested.
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
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The following steps are needed to set up the LVD
module:
21.2 Operation
Depending on the power source for the device voltage,
the voltage normally decreases relatively slowly. This
means that the LVD module does not need to be
constantly operating. To decrease the current
requirements, the LVD circuitry only needs to be
enabled for short periods, where the voltage is
checked. After doing the check, the LVD module may
be disabled.
1. Write the value to the LVDL3:LVDL0 bits
(LVDCON register), which selects the desired
LVD Trip Point.
2. Ensure that LVD interrupts are disabled (the
LVDIE bit is cleared or the GIE bit is cleared).
3. Enable the LVD module (set the LVDEN bit in
the LVDCON register).
4. Wait for the LVD module to stabilize (the IRVST
bit to become set).
Each time that the LVD module is enabled, the circuitry
requires some time to stabilize. After the circuitry has
stabilized, all status flags may be cleared. The module
will then indicate the proper state of the system.
5. Clear the LVD interrupt flag, which may have
falsely become set until the LVD module has
stabilized (clear the LVDIF bit).
6. Enable the LVD interrupt (set the LVDIE and the
GIE bits).
Figure 21-4 shows typical waveforms that the LVD
module may be used to detect.
FIGURE 21-4:
LOW-VOLTAGE DETECT WAVEFORMS
CASE 1:
LVDIF may not be set
VDD
VLVD
LVDIF
Enable LVD
Internally Generated
Reference Stable
TIVRST
LVDIF cleared in software
CASE 2:
VDD
VLVD
LVDIF
Enable LVD
TIVRST
Internally Generated
Reference Stable
LVDIF cleared in software
LVDIF cleared in software,
LVDIF remains set since LVD condition still exists
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21.2.1
REFERENCE VOLTAGE SET POINT
21.3 Operation During Sleep
The internal reference voltage of the LVD module may
be used by other internal circuitry (the Programmable
Brown-out Reset). If these circuits are disabled (lower
current consumption), the reference voltage circuit
requires a time to become stable before a low-voltage
condition can be reliably detected. This time is invariant
of system clock speed. This start-up time is specified in
electrical specification parameter 36. The low-voltage
interrupt flag will not be enabled until a stable reference
voltage is reached. Refer to the waveform in Figure 21-4.
When enabled, the LVD circuitry continues to operate
during Sleep. If the device voltage crosses the trip
point, the LVDIF bit will be set and the device will wake-
up from Sleep. Device execution will continue from the
interrupt vector address if interrupts have been globally
enabled.
21.4 Effects of a Reset
A device Reset forces all registers to their Reset state.
This forces the LVD module to be turned off.
21.2.2
CURRENT CONSUMPTION
When the module is enabled, the LVD comparator and
voltage divider are enabled and will consume static
current. The voltage divider can be tapped from
multiple places in the resistor array. Total current
consumption, when enabled, is specified in electrical
specification parameter #D022B.
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NOTES:
DS39616B-page 266
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22.1 Configuration Bits
22.0 SPECIAL FEATURES OF THE
CPU
The configuration bits can be programmed (read as
‘0’), or left unprogrammed (read as ‘1’), to select
various device configurations. These bits are mapped
starting at program memory location 300000h.
PIC18F2331/2431/4331/4431 devices include several
features intended to maximize system reliability and
minimize cost through elimination of external compo-
nents. These are:
The user will note that address 300000h is beyond the
user program memory space. In fact, it belongs to the
configuration memory space (300000h-3FFFFFh),
which can only be accessed using table reads and
table writes.
• Oscillator Selection
• Resets:
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
Programming the configuration registers is done in a
manner similar to programming the Flash memory. The
EECON1 register WR bit starts a self-timed write to the
Configuration register. In normal Operation mode, a
TBLWT instruction with the TBLPTR pointing to the
Configuration register sets up the address and the data
for the configuration register write. Setting the WR bit
starts a long write to the Configuration register. The
configuration registers are written a byte at a time. To
write or erase a configuration cell, a TBLWTinstruction
can write a ‘1’ or a ‘0’ into the cell. For additional details
on Flash programming, refer to Section 6.5 “Writing
to Flash Program Memory”.
• Watchdog Timer (WDT)
• Fail-Safe Clock Monitor
• Two-Speed Start-up
• Code Protection
• ID Locations
• In-Circuit Serial Programming™ (ICSP™)
The oscillator can be configured for the application
depending on frequency, power, accuracy and cost. All
of the options are discussed in detail in Section 2.0
“Oscillator Configurations”.
A complete discussion of device Resets and interrupts
is available in previous sections of this data sheet.
In addition to their Power-up and Oscillator start-up tim-
ers provided for Resets, PIC18F2331/2431/4331/4431
devices have a Watchdog Timer, which is either perma-
nently enabled via the configuration bits, or software
controlled (if configured as disabled).
The inclusion of an internal RC oscillator also provides
the additional benefits of a Fail-Safe Clock Monitor
(FSCM) and Two-Speed Start-up. FSCM provides for
background monitoring of the peripheral clock and
automatic switchover in the event of its failure. Two-
Speed Start-up enables code to be executed almost
immediately on start-up, while the primary clock source
completes its start-up delays.
All of these features are enabled and configured by
setting the appropriate configuration register bits.
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TABLE 22-1: CONFIGURATION BITS AND DEVICE IDS
Default/
Unprogrammed
Value
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
300000h CONFIG1L
300001h CONFIG1H
300002h CONFIG2L
300003h CONFIG2H
—
IESO
—
—
FCMEN
—
—
—
—
—
—
—
—
—
---- ----
11-- 1111
---- 1111
---1 1111
--11 11--
1--1 1-11
FOSC3
BORV1
WDPS2
LPOL
FOSC2
BORV0
WDPS1
PWMPIN
FOSC1
FOSC0
—
—
BOREN PWRTEN
—
—
WINEN
T1OSCMX
—
WDPS3
HPOL
WDPS0
—
WDTEN
—
CONFIG3L
300004h
—
—
—
300005h CONFIG3H
MCLRE
EXCLKMX PWM4MX SSPMX
—
FLTAMX
STVREN
—
300006h CONFIG4L DEBUG
—
—
—
—
—
—
LVP
—
—
1--- -1-1
---- ----
---- 1111
11-- ----
---- 1111
111- ----
---- 1111
-1-- ----
CONFIG4H
300007h
—
—
—
—
—
300008h CONFIG5L
300009h CONFIG5H
30000Ah CONFIG6L
—
—
—
CP3
—
CP2
—
CP1
—
CP0
CPD
—
CPB
—
—
—
—
—
—
WRT3
—
WRT2
—
WRT1
—
WRT0
—
30000Bh CONFIG6H WRTD
WRTB
—
WRTC
—
—
30000Ch CONFIG7L
30000Dh CONFIG7H
—
—
—
EBTR3
—
EBTR2
—
EBTR1
—
EBTR0
—
EBTRB
DEV1
DEV9
—
—
(1)
(1)
3FFFFEh DEVID1
DEV2
DEV10
DEV0
DEV8
REV4
DEV7
REV3
DEV6
REV2
DEV5
REV1
DEV4
REV0
DEV3
xxxx xxxx
(1)
3FFFFFh DEVID2
0000 0101
Legend:
x= unknown, u= unchanged, – = unimplemented, q= value depends on condition.
Shaded cells are unimplemented, read as ‘0’.
Note 1: See Register 22-13 for DEVID1 values. DEVID registers are read-only and cannot be programmed by the user.
REGISTER 22-1: CONFIG1H: CONFIGURATIONREGISTER1HIGH(BYTEADDRESS300001h)
R/P-1
IESO
R/P-1
U-0
—
U-0
—
R/P-1
R/P-1
R/P-1
R/P-1
FCMEN
FOSC3
FOSC2
FOSC1
FOSC0
bit 7
bit 0
bit 7
bit 6
IESO: Internal External Switch Over bit
1= Internal External Switch Over mode enabled
0= Internal External Switch Over mode disabled
FCMEN: Fail-Safe Clock Monitor Enable bit
1= Fail-Safe Clock Monitor enabled
0= Fail-Safe Clock Monitor disabled
bit 5-4 Unimplemented: Read as ‘0’
bit 3-0 FOSC<3:0>: Oscillator Selection bits
11xx= External RC oscillator, CLKO function on RA6
1001= Internal oscillator block, CLKO function on RA6, and port function on RA7
1000= Internal oscillator block, port function on RA6, and port function on RA7
0111= External RC oscillator, port function on RA6
0110= HS oscillator, PLL enabled (clock frequency = 4 x FOSC1)
0101= EC oscillator, port function on RA6
0100= EC oscillator, CLKO function on RA6
0010= HS oscillator
0001= XT oscillator
0000= LP oscillator
Legend:
R = Readable bit
P = Programmable bit
U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed
u = Unchanged from programmed state
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REGISTER 22-2: CONFIG2L: CONFIGURATION REGISTER 2LOW(BYTEADDRESS300002h)
U-0
—
U-0
—
U-0
—
U-0
—
R/P-1
R/P-1
R/P-1
R/P-1
BORV1
BORV0
BOREN PWRTEN
bit 0
bit 7
bit 7-4 Unimplemented: Read as ‘0’
bit 3-2 BORV1:BORV0: Brown-out Reset Voltage bits
11= Reserved
10= VBOR set to 2.7V
01= VBOR set to 4.2V
00= VBOR set to 4.5V
bit 1
bit 0
BOREN: Brown-out Reset Enable bit(1)
1= Brown-out Reset enabled
0= Brown-out Reset disabled
PWRTEN: Power-up Timer Enable bit(1)
1= PWRT disabled
0= PWRT enabled
Note 1: Having BOREN = 1 does not automatically override the PWRTEN to ‘0’ nor
automatically enable the Power-up Timer.
Legend:
R = Readable bit
- n = Value when device is unprogrammed
P = Programmable bit
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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REGISTER 22-3: CONFIG2H: CONFIGURATIONREGISTER 2HIGH (BYTEADDRESS300003h)
U-0
—
U-0
—
R/P-1
R/P-1
R/P-1
R/P-1
R/P-1
R/P-1
WINEN
WDTPS3 WDTPS2 WDTPS1 WDTPS0 WDTEN
bit 0
bit 7
bit 7-6 Unimplemented: Read as ‘0’
bit 5 WINEN: Watchdog Timer Window Enable bit
1= WDT Window disabled
0= WDT Window enabled
bit 4-1 WDPS<3:0>: Watchdog Timer Postscale Select bits
1111= 1:32,768
1110= 1:16,384
1101= 1:8,192
1100= 1:4,096
1011= 1:2,048
1010= 1:1,024
1001= 1:512
1000= 1:256
0111= 1:128
0110= 1:64
0101= 1:32
0100= 1:16
0011= 1:8
0010= 1:4
0001= 1:2
0000= 1:1
bit 0
WDTEN: Watchdog Timer Enable bit
1= WDT enabled
0= WDT disabled (control is placed on the SWDTEN bit)
Legend:
R = Readable bit
P = Programmable bit
U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed
u = Unchanged from programmed state
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REGISTER 22-4: CONFIG3L: CONFIGURATION REGISTER 3 LOW (BYTE ADDRESS 300004h)
U-0
—
U
R/P-1
R/P-1
HPOL
R/P-1
LPOL
R/P-1
U
U
—
T1OSCMX
PWMPIN
—
—
bit 7
bit 0
bit 7-6 Unimplemented: Read as ‘0’
bit 5
bit 4
T1OSCMX: Timer1 Oscillator Mode bit
1= Low power Timer1 operation when microcontroller is in Sleep mode.
0= Standard (legacy) Timer1 oscillator operation.
HPOL(1): High-Side Transistors Polarity bit (i.e., odd PWM output polarity control bit )
1= PWM 1, 3, 5 and 7 are active-high (default)
0= PWM 1, 3, 5 and 7 are active-low
bit 3
bit 2
LPOL(1): Low-Side Transistors Polarity bit (i.e., even PWM output polarity control bit)
1= PWM 0, 2, 4 and 6 are active-high (default)
0= PWM 0, 2, 4 and 6 are active-low
PWMPIN(2): PWM output pins Reset state control bit
1= PWM outputs disabled upon Reset (default)
0= PWM outputs drive active states upon Reset(3)
bit 1-0 Unimplemented: Read as ‘0’
Note 1: Polarity control bits HPOL and LPOL define PWM signal output active and inactive
states; PWM states generated by the fault inputs or PWM manual override.
2: PWM6 and PWM7 output channels are only available on the PIC18F4X21 devices.
3: When PWMPIN = 0, PWMEN<2:0> = 101 if device has eight PWM output pins (40
and 44-pin devices) and PWMEN<2:0> = 100if the device has six PWM output pins
(28-pin device). PWM output polarity is defined by HPOL and LPOL.
Legend:
R = Readable bit
- n = Value when device is unprogrammed
P = Programmable bit
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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REGISTER 22-5: CONFIG3H: CONFIGURATIONREGISTER3HIGH(BYTEADDRESS300005h)
R/P-1
U
U
R/P-1
R/P-1
R/P-1
U
R/P-1
EXCLKMX(1) PWM4MX(1) SSPMX(1)
FLTAMX(1)
bit 0
MCLRE
—
—
—
bit 7
bit 7
MCLRE: MCLR Pin Enable bit
1= RE3 input pin enabled; MCLR disabled.
0= MCLR pin enabled: RE3 input pin disabled.
bit 6-5
bit 4
Unimplemented: Read as ‘0’
EXCLKMX: TMR0/T5CKI External Clock Mux bit
1= TMR0/T5CKI external clock input is multiplexed with RC3
0= TMR0/T5CKI external clock input is multiplexed with RD0
bit 3
bit 2
PWM4MX: PWM4 Mux bit
1= PWM4 output is multiplexed with RB5
0= PWM4 output is multiplexed with RD5
SSPMX: SSP I/O Mux bit
1= SCK/SCL clocks and SDA/SDI data are multiplexed with RC5 and RC4 respectively.
SDO output is multiplexed with RC7.
0= SCK/SCL clocks and SDA/SDI data are multiplexed with RD3 and RD2 respectively.
SDO output is multiplexed with RD1.
bit 1
bit 0
Unimplemented: Read as ‘0’
FLTAMX: FLTA Mux bit
1= FLTA input is multiplexed with RC1
0= FLTA input is multiplexed with RD4
Note 1: Unimplemented in PIC18F2X31 devices; maintain this bit set.
Legend:
R = Readable bit
P = Programmable bit
U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed
u = Unchanged from programmed state
DS39616B-page 272
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
REGISTER 22-6: CONFIG4L: CONFIGURATION REGISTER 4LOW(BYTEADDRESS300006h)
R/P-1
DEBUG
bit 7
U-0
—
U-0
—
U-0
—
U-0
—
R/P-1
LVP
U-0
—
R/P-1
STVREN
bit 0
bit 7
DEBUG: Background Debugger Enable bit
1= Background Debugger disabled, RB6 and RB7 configured as general purpose I/O pins
0= Background Debugger enabled, RB6 and RB7 are dedicated to in-circuit debug
bit 6-3 Unimplemented: Read as ‘0’
bit 2
LVP: Low-Voltage ICSP Enable bit
1= Low-Voltage ICSP enabled
0= Low-Voltage ICSP disabled
bit 1
bit 0
Unimplemented: Read as ‘0’
STVREN: Stack Full/Underflow Reset Enable bit
1= Stack Full/Underflow will cause Reset
0= Stack Full/Underflow will not cause Reset
Legend:
R = Readable bit
C = Clearable bit
U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed
u = Unchanged from programmed state
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 273
PIC18F2331/2431/4331/4431
REGISTER 22-7: CONFIG5L: CONFIGURATION REGISTER 5LOW(BYTEADDRESS300008h)
U-0
—
U-0
—
U-0
—
U-0
—
R/C-1
CP3(1)
R/C-1
CP2(1)
R/C-1
CP1
R/C-1
CP0
bit 7
bit 0
bit 7-4 Unimplemented: Read as ‘0’
bit 3
bit 2
bit 1
bit 0
CP3: Code Protection bit
1= Block 3 (001800-001FFFh) not code-protected
0= Block 3 (001800-001FFFh) code-protected
CP2: Code Protection bit
1= Block 2 (001000-0017FFh) not code-protected
0= Block 2 (001000-0017FFh) code-protected
CP1: Code Protection bit
1= Block 1 (000800-000FFFh) not code-protected
0= Block 1 (000800-000FFFh) code-protected
CP0: Code Protection bit
1= Block 0 (000200-0007FFh) not code-protected
0= Block 0 (000200-0007FFh) code-protected
Note 1: Unimplemented in PIC18F2X31 devices; maintain this bit set.
Legend:
R = Readable bit
- n = Value when device is unprogrammed
C = Clearable bit
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
REGISTER 22-8: CONFIG5H: CONFIGURATIONREGISTER5HIGH(BYTEADDRESS300009h)
R/C-1
CPD
R/C-1
CPB
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
bit 7
bit 0
bit 7
bit 6
CPD: Data EEPROM Code Protection bit
1= Data EEPROM not code-protected
0= Data EEPROM code-protected
CPB: Boot Block Code Protection bit
1= Boot block (000000-0001FFh) not code-protected
0= Boot block (000000-0001FFh) code-protected
bit 5-0 Unimplemented: Read as ‘0’
Legend:
R = Readable bit
C = Clearable bit
U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed
u = Unchanged from programmed state
DS39616B-page 274
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
REGISTER 22-9: CONFIG6L: CONFIGURATIONREGISTER6LOW(BYTEADDRESS30000Ah)
U-0
—
U-0
—
U-0
—
U-0
—
R/P-1
WRT3(1) WRT2(1)
R/P-1
R/P-1
R/P-1
WRT1
WRT0
bit 7
bit 0
bit 7-4 Unimplemented: Read as ‘0’
bit 3
bit 2
bit 1
bit 0
WRT3: Write Protection bit(1)
1= Block 3 (001800-001FFFh) not write-protected
0= Block 3 (001800-001FFFh) write-protected
WRT2: Write Protection bit(1)
1= Block 2 (001000-0017FFh) not write-protected
0= Block 2 (001000-0017FFh) write-protected
WRT1: Write Protection bit
1= Block 1 (000800-000FFFh) not write-protected
0= Block 1 (000800-000FFFh) write-protected
WRT0: Write Protection bit
1= Block 0 (000200-0007FFh) not write-protected
0= Block 0 (000200-0007FFh) write-protected
Note 1: Unimplemented in PIC18F2X31 devices; maintain this bit set.
Legend:
R = Readable bit
- n = Value when device is unprogrammed
P = Programmable bit
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
REGISTER 22-10: CONFIG6H: CONFIGURATIONREGISTER6HIGH(BYTEADDRESS30000Bh)
R/P-1
R/P-1
R-1
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
WRTD
WRTB
WRTC
bit 7
bit 0
bit 7
bit 6
bit 5
WRTD: Data EEPROM Write Protection bit
1= Data EEPROM not write-protected
0= Data EEPROM write-protected
WRTB: Boot Block Write Protection bit
1= Boot block (000000-0001FFh) not write-protected
0= Boot block (000000-0001FFh) write-protected
WRTC: Configuration Register Write Protection bit
1= Configuration registers (300000-3000FFh) not write-protected
0= Configuration registers (300000-3000FFh) write-protected
Note:
This bit is read-only in normal Execution mode; it can be written only in
Program mode.
bit 4-0 Unimplemented: Read as ‘0’
Legend:
R = Readable bit
P = Programmable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed
u = Unchanged from programmed state
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 275
PIC18F2331/2431/4331/4431
REGISTER 22-11: CONFIG7L: CONFIGURATIONREGISTER7LOW(BYTEADDRESS30000Ch)
U-0
—
U-0
—
U-0
—
U-0
—
R/P-1
EBTR3(1) EBTR2(1)
R/P-1
R/P-1
R/P-1
EBTR1
EBTR0
bit 7
bit 0
bit 7-4 Unimplemented: Read as ‘0’
bit 3
bit 2
bit 1
bit 0
EBTR3: Table Read Protection bit(1)
1= Block 3 (001800-001FFFh) not protected from table reads executed in other blocks
0= Block 3 (001800-001FFFh) protected from table reads executed in other blocks
EBTR2: Table Read Protection bit(1)
1= Block 2 (001000-0017FFh) not protected from table reads executed in other blocks
0= Block 2 (001000-0017FFh) protected from table reads executed in other blocks
EBTR1: Table Read Protection bit
1= Block 1 (000800-000FFFh) not protected from table reads executed in other blocks
0= Block 1 (000800-000FFFh) protected from table reads executed in other blocks
EBTR0: Table Read Protection bit
1= Block 0 (000200-0007FFh) not protected from table reads executed in other blocks
0= Block 0 (000200-0007FFh) protected from table reads executed in other blocks
Note 1: Unimplemented in PIC18F2X31 devices; maintain this bit set.
Legend:
R = Readable bit
P = Programmable bit
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
- n = Value when device is unprogrammed
REGISTER 22-12: CONFIG7H: CONFIGURATIONREGISTER7HIGH(BYTEADDRESS30000Dh)
U-0
—
R/P-1
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
EBTRB
bit 7
bit 0
bit 7
bit 6
Unimplemented: Read as ‘0’
EBTRB: Boot Block Table Read Protection bit
1= Boot block (000000-0001FFh) not protected from table reads executed in other blocks
0= Boot block (000000-0001FFh) protected from table reads executed in other blocks
bit 5-0 Unimplemented: Read as ‘0’
Legend:
R = Readable bit
P = Programmable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed
u = Unchanged from programmed state
DS39616B-page 276
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
REGISTER 22-13: DEVICE ID REGISTER 1 FOR PIC18F2331/2431/4331/4431 DEVICES
R
R
R
R
R
R
R
R
DEV2
DEV1
DEV0
REV4
REV3
REV2
REV1
REV0
bit 7
bit 0
bit 7-5 DEV<2:0>: Device ID bits
These bits are used with the DEV<10:3> bits in the Device ID register 2 to identify the part
number.
000= PIC18F4331
001= PIC18F4431
100= PIC18F2331
101= PIC18F2431
bit 4-0 REV<4:0>: Revision ID bits
These bits are used to indicate the device revision.
Legend:
R = Read-only bit
P = Programmable bit U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
- n = Value when device is unprogrammed
REGISTER 22-14: DEVICE ID REGISTER 2 FOR PIC18F2331/2431/4331/4431 DEVICES
R
R
R
R
R
R
R
R
DEV10
DEV9
DEV8
DEV7
DEV6
DEV5
DEV4
DEV3
bit 7
bit 0
bit 7-0 DEV10:DEV3: Device ID bits
These bits are used with the DEV2:DEV0 bits in the Device ID Register 1 to identify the
part number
0000 0101= PIC18F2331/2431/4331/4431 devices
Note 1: These values for DEV10:DEV3 may be shared with other devices. The specific
device is always identified by using the entire DEV10:DEV0 bit sequence.
Legend:
R = Read-only bit
- n = Value when device is unprogrammed
P = Programmable bit U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 277
PIC18F2331/2431/4331/4431
22.2 Watchdog Timer (WDT)
Note 1: The CLRWDT and SLEEP instructions
clear the WDT and postscaler counts
when executed.
For PIC18F2331/2431/4331/4431 devices, the WDT is
driven by the INTRC source. When the WDT is
enabled, the clock source is also enabled. The nominal
WDT period is 4 ms and has the same stability as the
INTRC oscillator.
2: Changing the setting of the IRCF bits
(OSCCON<6:4> clears the WDT and
postscaler counts.
The 4 ms period of the WDT is multiplied by a 16-bit
postscaler. Any output of the WDT postscaler is
selected by a multiplexer, controlled by bits in
Configuration Register 2H (see Register 22-3).
Available periods range from 4 ms to 131.072 seconds
(2.18 minutes). The WDT and postscaler are cleared
when any of the following events occur: execute a
SLEEP or CLRWDT instruction, the IRCF bits
(OSCCON<6:4>) are changed, or a clock failure has
occurred (see Section 22.4.1 “FSCM and the
Watchdog Timer”).
3: When a CLRWDT instruction is executed
the postscaler count will be cleared.
4: If WINEN = 0, then CLRWDT must be
executed only when WDTW = 1; other-
wise, a device reset will result.
22.2.1
CONTROL REGISTER
Register 22-15 shows the WDTCON register. This is a
readable and writable register. The SWDTEN bit allows
software to enable or disable the WDT, but only if the
configuration bit has disabled the WDT. The WDTW bit
is a read-only bit that indicates when the WDT count is
in the fourth quadrant (i.e., when the 8-bit WDT value is
b’11000000’ or greater).
Adjustments to the internal oscillator clock period using
the OSCTUNE register also affect the period of the
WDT by the same factor. For example, if the INTRC
period is increased by 3%, then the WDT period is
increased by 3%.
FIGURE 22-1:
WDT BLOCK DIAGRAM
Enable WDT
SWDTEN
WDTEN
INTRC Control
WDT Counter
Wake-up
from Sleep
÷125
INTRC Source
Change on IRCF Bits
CLRWDT
WDT
Reset
Reset
Programmable Postscaler
1:1 to 1:32,768
All Device Resets
WDT
4
WDTPS<3:0>
Sleep
REGISTER 22-15: WDTCON REGISTER
R-0
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
R/W-0
SWDTEN
bit 0
WDTW
bit 7
bit 7
WDTW: Watchdog Timer Window bit
1= WDT count is in fourth quadrant
0= WDT count is not in fourth quadrant
bit 6
bit 0
Unimplemented
(1)
SWDTEN: Software Enable / Disable for Watch Dog Timer bit
1= WDT is turned on
0= WDT is turned off
Note 1: If WDTEN configuration bit = 1, then WDT is always enabled, irrespective of this control
bit. If WDTEN configuration bit = 0, then it is possible to turn WDT on/off with this con-
trol bit.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
DS39616B-page 278
Preliminary
2003 Microchip Technology Inc.
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TABLE 22-2: SUMMARY OF WATCHDOG TIMER REGISTERS
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CONFIG2H
RCON
—
—
—
—
WINEN
—
WDTPS3 WDTPS2 WDTPS2 WDTPS0
WDTEN
BOR
IPEN
WDTW
RI
—
TO
—
PD
—
POR
—
WDTCON
SWDTEN
—
Legend: Shaded cells are not used by the Watchdog Timer.
22.3.1
SPECIAL CONSIDERATIONS FOR
USING TWO-SPEED START-UP
22.3 Two-Speed Start-up
The Two-Speed Start-up feature helps to minimize the
latency period from oscillator start-up to code execution
by allowing the microcontroller to use the INTRC oscil-
lator as a clock source until the primary clock source is
available. It is enabled by setting the IESO bit in
Configuration Register 1H (CONFIG1H<7>).
While using the INTRC oscillator in Two-Speed Start-
up, the device still obeys the normal command
sequences for entering power-managed modes,
including serial SLEEP instructions (refer to
Section 3.1.3 “Multiple Sleep Commands”). In prac-
tice, this means that user code can change the
SCS1:SCS0 bit settings and issue SLEEPcommands
before the OST times out. This would allow an applica-
tion to briefly wake-up, perform routine “housekeeping”
tasks and return to Sleep before the device starts to
operate from the primary oscillator.
Two-Speed Start-up is available only if the primary
Oscillator mode is LP, XT, HS or HSPLL (crystal-based
modes). Other sources do not require a OST start-up
delay; for these, Two-Speed Start-up is disabled.
When enabled, Resets and wake-ups from Sleep mode
cause the device to configure itself to run from the inter-
nal oscillator block as the clock source, following the
time-out of the Power-up Timer after a POR Reset is
enabled. This allows almost immediate code execu-
tion, while the primary oscillator starts and the OST is
running. Once the OST times out, the device automat-
ically switches to PRI_RUN mode.
User code can also check if the primary clock source is
currently providing the system clocking by checking the
status of the OSTS bit (OSCCON<3>). If the bit is set,
the primary oscillator is providing the system clock.
Otherwise, the internal oscillator block is providing the
clock during wake-up from Reset or Sleep mode.
Because the OSCCON register is cleared on Reset
events, the INTOSC (or postscaler) clock source is not
initially available after a Reset event; the INTRC clock
is used directly at its base frequency. To use a higher
clock speed on wake-up, the INTOSC or postscaler
clock sources can be selected to provide a higher clock
speed by setting bits IFRC2:IFRC0 immediately after
Reset. For wake-ups from Sleep, the INTOSC or
postscaler clock sources can be selected by setting
IFRC2:IFRC0 prior to entering Sleep mode.
In all other power-managed modes, Two-Speed Start-
up is not used. The device will be clocked by the cur-
rently selected clock source until the primary clock
source becomes available. The setting of the IESO bit
is ignored.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 279
PIC18F2331/2431/4331/4431
FIGURE 22-2:
TIMING TRANSITION FOR TWO-SPEED START-UP (INTOSC TO HSPLL)
Q3
Q4
Q1
Q2 Q3 Q4 Q1 Q2 Q3 Q4
Q1
Q2
INTOSC
Multiplexer
OSC1
(1)
(1)
TOST
TPLL
PLL Clock
Output
1
2
3
4
5
6
7
8
Clock Transition
CPU Clock
Peripheral
Clock
Program
Counter
PC + 4
PC
PC + 2
PC + 6
OSTS bit Set
Note 1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
Wake from Interrupt Event
DS39616B-page 280
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To use a higher clock speed on wake-up, the INTOSC
or postscaler clock sources can be selected to provide
a higher clock speed by setting bits IFRC2:IFRC0
immediately after Reset. For wake-ups from Sleep, the
INTOSC or postscaler clock sources can be selected
by setting IFRC2:IFRC0 prior to entering Sleep mode.
22.4 Fail-Safe Clock Monitor
The Fail-Safe Clock Monitor (FSCM) allows the
microcontroller to continue operation in the event of an
external oscillator failure, by automatically switching
the system clock to the internal oscillator block. The
FSCM function is enabled by setting the Fail-Safe
Clock Monitor Enable bit, FCMEN (CONFIG1H<6>).
Adjustments to the internal oscillator block using the
OSCTUNE register also affect the period of the FSCM
by the same factor. This can usually be neglected, as
the clock frequency being monitored is generally much
higher than the sample clock frequency.
When FSCM is enabled, the INTRC oscillator runs at
all times to monitor clocks to peripherals and provide
an instant backup clock in the event of a clock failure.
Clock monitoring (shown in Figure 22-3) is
accomplished by creating a sample clock signal, which
is the INTRC output divided by 64. This allows ample
time between FSCM sample clocks for a peripheral
clock edge to occur. The peripheral system clock and
the sample clock are presented as inputs to the Clock
Monitor latch (CM). The CM is set on the falling edge of
the system clock source, but cleared on the rising edge
of the sample clock.
The FSCM will detect failures of the primary or second-
ary clock sources only. If the internal oscillator block
fails, no failure would be detected, nor would any action
be possible.
22.4.1
FSCM AND THE WATCHDOG TIMER
Both the FSCM and the WDT are clocked by the
INTRC oscillator. Since the WDT operates with a
separate divider and counter, disabling the WDT has
no effect on the operation of the INTRC oscillator when
the FSCM is enabled.
FIGURE 22-3:
FSCM BLOCK DIAGRAM
Clock Monitor
Latch (CM)
(edge-triggered)
As already noted, the clock source is switched to the
INTOSC clock when a clock failure is detected.
Depending on the frequency selected by the
IRCF2:IRCF0 bits, this may mean a substantial change
in the speed of code execution. If the WDT is enabled
with a small prescale value, a decrease in clock speed
allows a WDT time-out to occur, and a subsequent
device Reset. For this reason, fail-safe clock events
also reset the WDT and postscaler, allowing it to start
timing from when execution speed was changed and
decreasing the likelihood of an erroneous time-out.
Peripheral
Clock
S
Q
Q
INTRC
Source
C
÷ 64
(32 µs)
488 Hz
(2.048 ms)
Clock
Failure
Detected
22.4.2
EXITING FAIL-SAFE OPERATION
The fail-safe condition is terminated by either a device
Reset, or by entering a power-managed mode. On Reset,
the controller starts the primary clock source specified in
Configuration Register 1H (with any required start-up
delays that are required for the Oscillator mode, such as
OST or PLL timer). The INTOSC multiplexer provides the
system clock until the primary clock source becomes
ready (similar to a Two-Speed Start-up). The clock system
source is then switched to the primary clock (indicated by
the OSTS bit in the OSCCON register becoming set). The
Fail-Safe Clock Monitor then resumes monitoring the
peripheral clock.
Clock failure is tested for on the falling edge of the
sample clock. If a sample clock falling edge occurs
while CM is still set, a clock failure has been detected
(Figure 22-4). This causes the following:
• the FSCM generates an oscillator fail interrupt by
setting bit OSCFIF (PIR2<7>);
• the system clock source is switched to the internal
oscillator block (OSCCON is not updated to show
the current clock source – this is the fail-safe
condition); and
• the WDT is reset.
The primary clock source may never become ready
during start-up. In this case, operation is clocked by the
INTOSC multiplexer. The OSCCON register will remain in
its Reset state until a power-managed mode is entered.
Since the postscaler frequency from the internal
oscillator block may not be sufficiently stable, it may be
desirable to select another clock configuration and
enter an alternate power-managed mode (see
Section 22.3.1 “Special Considerations for Using
Two-Speed Start-up” and Section 3.1.3 “Multiple
Sleep Commands” for more details). This can be
done to attempt a partial recovery or execute a
controlled shutdown.
Entering a power-managed mode by loading the
OSCCON register and executing a SLEEP instruction
will clear the fail-safe condition. When the fail-safe
condition is cleared, the clock monitor will resume
monitoring the peripheral clock.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 281
PIC18F2331/2431/4331/4431
FIGURE 22-4:
FSCM TIMING DIAGRAM
Sample Clock
Oscillator
Failure
System
Clock
Output
CM Output
(Q)
Failure
Detected
OSCFIF
CM Test
CM Test
CM Test
Note:
The system clock is normally at a much higher frequency than the sample clock. The relative frequencies in
this example have been chosen for clarity.
22.4.3
FSCM INTERRUPTS IN POWER-
MANAGED MODES
22.4.4
POR OR WAKE FROM SLEEP
The FSCM is designed to detect oscillator failure at any
point after the device has exited Power-on Reset
(POR) or Low-Power Sleep mode. When the primary
system clock is EC, RC or INTRC modes, monitoring
can begin immediately following these events.
As previously mentioned, entering a power-managed
mode clears the fail-safe condition. By entering a
power-managed mode, the clock multiplexer selects
the clock source selected by the OSCCON register.
Fail-safe monitoring of the power-managed clock
source resumes in the power-managed mode.
For oscillator modes involving a crystal or resonator
(HS, HSPLL, LP or XT), the situation is somewhat
different. Since the oscillator may require a start-up
time considerably longer than the FCSM sample clock
time, a false clock failure may be detected. To prevent
this, the internal oscillator block is automatically
configured as the system clock and functions until the
primary clock is stable (the OST and PLL timers have
timed out). This is identical to Two-Speed Start-up
mode. Once the primary clock is stable, the INTRC
returns to its role as the FSCM source.
If an oscillator failure occurs during power-managed
operation, the subsequent events depend on whether
or not the oscillator failure interrupt is enabled. If
enabled (OSCFIF = 1), code execution will be clocked
by the INTOSC multiplexer. An automatic transition
back to the failed clock source will not occur.
If the interrupt is disabled, the device will not exit the
power-managed mode on oscillator failure. Instead, the
device will continue to operate as before, but clocked
by the INTOSC multiplexer. While in Idle mode, subse-
quent interrupts will cause the CPU to begin executing
instructions while being clocked by the INTOSC multi-
plexer. The device will not transition to a different clock
source until the fail-safe condition is cleared.
Note:
The same logic that prevents false
oscillator failure interrupts on POR or
wake from Sleep will also prevent the
detection of the oscillator’s failure to start
at all following these events. This can be
avoided by monitoring the OSTS bit and
using a timing routine to determine if the
oscillator is taking too long to start. Even
so, no oscillator failure interrupt will be
flagged.
As noted in Section 22.3.1 “Special Considerations
for Using Two-Speed Start-up”, it is also possible to
select another clock configuration and enter an
alternate power-managed mode, while waiting for the
primary system clock to become stable. When the new
Powered Managed mode is selected, the primary clock
is disabled.
DS39616B-page 282
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
Each of the five blocks has three code protection bits
associated with them. They are:
22.5 Program Verification and
Code Protection
• Code-Protect bit (CPn)
The overall structure of the code protection on the
PIC18 Flash devices differs significantly from other
PICmicro® devices.
• Write-Protect bit (WRTn)
• External Block Table Read bit (EBTRn)
Figure 22-5 shows the program memory organization
for 8- and 16-Kbyte devices, and the specific code
protection bit associated with each block. The actual
locations of the bits are summarized in Table 22-3.
The user program memory is divided into five blocks.
One of these is a boot block of 512 bytes. The
remainder of the memory is divided into four blocks on
binary boundaries.
FIGURE 22-5:
CODE-PROTECTED PROGRAM MEMORY FOR PIC18F2331/2431/4331/4431
MEMORY SIZE/DEVICE
Block Code Protection
Controlled By:
8 Kbytes
(PIC18FX331)
Address
Range
16 Kbytes
(PIC18FX431)
Address
Range
0000h
0FFFh
0000h
01FFh
Boot Block
Boot Block
Block 0
CPB, WRTB, EBTRB
CP0, WRT0, EBTR0
0200h
0200h
Block 0
Block 1
0FFFh
1000h
0FFFh
1000h
Block 1
Block 2
Block 3
CP1, WRT1, EBTR1
CP2, WRT2, EBTR2
CP3, WRT3, EBTR3
1FFFh
1FFFh
2000h
2FFFh
3000h
Unimplemented
Read 0’s
3FFFh
3FFFh
TABLE 22-3: SUMMARY OF CODE PROTECTION REGISTERS
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
300008h
CONFIG5L
CONFIG5H
CONFIG6L
—
CPD
—
—
CPB
—
—
—
—
—
—
—
—
—
CP3
—
CP2
—
CP1
—
CP0
—
300009h
30000Ah
30000Bh
30000Ch
30000Dh
—
WRT3
—
WRT2
—
WRT1
—
WRT0
—
CONFIG6H WRTD
WRTB
—
WRTC
—
CONFIG7L
CONFIG7H
—
—
EBTR3
—
EBTR2
—
EBTR1
—
EBTR0
—
EBTRB
—
Legend: Shaded cells are unimplemented.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 283
PIC18F2331/2431/4331/4431
22.5.1
PROGRAM MEMORY
CODE PROTECTION
Note:
Code protection bits may only be written to
a ‘0’ from a ‘1’ state. It is not possible to
write a ‘1’ to a bit in the ‘0’ state. Code
protection bits are only set to ‘1’ by a full
chip erase or block erase function. The full
chip erase and block erase functions can
only be initiated via ICSP or an external
programmer.
The program memory may be read to or written from
any location using the table read and table write
instructions. The device ID may be read with table
reads. The configuration registers may be read and
written with the table read and table write instructions.
In normal Execution mode, the CPn bits have no direct
effect. CPn bits inhibit external reads and writes. A block
of user memory may be protected from table writes if the
WRTn configuration bit is ‘0’. The EBTRn bits control
table reads. For a block of user memory with the EBTRn
bit set to ‘0’, a table read instruction that executes from
within that block is allowed to read. A table read instruc-
tion that executes from a location outside of that block is
not allowed to read, and will result in reading ‘0’s.
Figures 22-6 through 22-8 illustrate table write and table
read protection.
FIGURE 22-6:
TABLE WRITE (WRTn) DISALLOWED
Register Values
Program Memory
Configuration Bit Settings
000000h
WRTB,EBTRB = 11
0001FFh
000200h
TBLPTR = 0002FFh
PC = 0007FEh
WRT0,EBTR0 = 01
TBLWT *
TBLWT *
0007FFh
000800h
WRT1,EBTR1 = 11
WRT2,EBTR2 = 11
WRT3,EBTR3 = 11
000FFFh
001000h
PC = 0017FEh
0017FFh
001800h
001FFFh
Results: All table writes disabled to Blockn whenever WRTn = ‘0’.
DS39616B-page 284
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FIGURE 22-7:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
Program Memory Configuration Bit Settings
Register Values
000000h
WRTB,EBTRB = 11
WRT0,EBTR0 = 10
0001FFh
000200h
TBLPTR = 0002FFh
0007FFh
000800h
TBLRD *
PC = 000FFEh
WRT1,EBTR1 = 11
WRT2,EBTR2 = 11
000FFFh
001000h
0017FFh
001800h
WRT3,EBTR3 = 11
001FFFh
Results: All table reads from external blocks to Blockn are disabled whenever EBTRn = ‘0’.
TABLAT register returns a value of ‘0’.
FIGURE 22-8:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
Register Values
Program Memory
Configuration Bit Settings
000000h
WRTB,EBTRB = 11
WRT0,EBTR0 = 10
0001FFh
000200h
TBLPTR = 0002FFh
PC = 0007FEh
TBLRD *
0007FFh
000800h
WRT1,EBTR1 = 11
WRT2,EBTR2 = 11
WRT3,EBTR3 = 11
000FFFh
001000h
0017FFh
001800h
001FFFh
Results: Table reads permitted within Blockn, even when EBTRBn = ‘0’.
TABLAT register returns the value of the data at the location TBLPTR.
2003 Microchip Technology Inc.
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To use the In-Circuit Debugger function of the micro-
controller, the design must implement In-Circuit Serial
Programming connections to MCLR/VPP, VDD, VSS,
RB7 and RB6. This will interface to the In-Circuit
Debugger module available from Microchip or one of
the third party development tool companies.
22.5.2
DATA EEPROM
CODE PROTECTION
The entire data EEPROM is protected from external
reads and writes by two bits: CPD and WRTD. CPD
inhibits external reads and writes of data EEPROM.
WRTD inhibits external writes to data EEPROM. The
CPU can continue to read and write data EEPROM
regardless of the protection bit settings.
22.9 Low-Voltage ICSP Programming
The LVP bit in Configuration Register 4L
(CONFIG4L<2>) enables Low-Voltage ICSP Program-
ming (LVP). When LVP is enabled, the microcontroller
can be programmed without requiring high voltage
being applied to the MCLR/VPP pin, but the RB5/PGM
pin is then dedicated to controlling Program mode entry
and is not available as a general purpose I/O pin.
22.5.3
CONFIGURATION REGISTER
PROTECTION
The configuration registers can be write-protected. The
WRTC bit controls protection of the configuration
registers. In normal Execution mode, the WRTC bit is
readable only. WRTC can only be written via ICSP or
an external programmer.
LVP is enabled in erased devices.
While programming using LVP, VDD is applied to the
MCLR/VPP pin as in normal Execution mode. To enter
Programming mode, VDD is applied to the PGM pin.
22.6 ID Locations
Eight memory locations (200000h-200007h) are
designated as ID locations, where the user can store
checksum or other code identification numbers. These
locations are both readable and writable during normal
execution through the TBLRDand TBLWTinstructions,
or during program/verify. The ID locations can be read
when the device is code-protected.
Note 1: High voltage programming is always
available, regardless of the state of the
LVP bit or the PGM pin, by applying VIHH
to the MCLR pin.
2: When Low-Voltage Programming is
enabled, the RB5 pin can no longer be
used as a general purpose I/O pin.
22.7
In-Circuit Serial Programming
3: When LVP is enabled, externally pull the
PGM pin to VSS to allow normal program
execution.
PIC18F2331/2431/4331/4431 microcontrollers can be
serially programmed while in the end application circuit.
This is simply done with two lines for clock and data,
and three other lines for power, ground and the pro-
gramming voltage. This allows customers to manufac-
ture boards with unprogrammed devices, and then
program the microcontroller just before shipping the
product. This also allows the most recent firmware or a
custom firmware to be programmed.
If Low-Voltage ICSP Programming mode will not be
used, the LVP bit can be cleared and RB5/PGM
becomes available as the digital I/O pin RB5. The LVP
bit may be set or cleared only when using standard high
voltage programming (VIHH applied to the MCLR/VPP
pin). Once LVP has been disabled, only the standard
high voltage programming is available and must be
used to program the device.
22.8 In-Circuit Debugger
Memory that is not code-protected can be erased using
either a block erase, or erased row by row, then written
at any specified VDD. If code-protected memory is to be
erased, a block erase is required. If a block erase is to
be performed when using low-voltage programming,
the device must be supplied with VDD of 4.5V to 5.5V.
When the DEBUG bit in configuration register
CONFIG4L is programmed to a ‘0’, the In-Circuit
Debugger functionality is enabled. This function allows
simple debugging functions when used with MPLAB®
IDE. When the microcontroller has this feature
enabled, some resources are not available for general
use. Table 22-4 shows which resources are required by
the background debugger.
TABLE 22-4: DEBUGGER RESOURCES
I/O pins:
RB6, RB7
Stack:
2 levels
Program Memory:
Data Memory:
512 bytes
10 bytes
DS39616B-page 286
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The control instructions may use some of the following
operands:
23.0 INSTRUCTION SET SUMMARY
The PIC18 instruction set adds many enhancements to
the previous PICmicro instruction sets, while maintain-
ing an easy migration from these PICmicro instruction
sets.
• A program memory address (specified by ‘n’)
• The mode of the Call or Return instructions
(specified by ‘s’)
• The mode of the table read and table write
instructions (specified by ‘m’)
Most instructions are a single program memory word
(16-bits), but there are three instructions that require
two program memory locations.
• No operand required
(specified by ‘—’)
Each single-word instruction is a 16-bit word divided
into an OPCODE, which specifies the instruction type
and one or more operands, which further specify the
operation of the instruction.
All instructions are a single word, except for three dou-
ble word instructions. These three instructions were
made double word instructions so that all the required
information is available in these 32 bits. In the second
word, the 4 MSbs are 1’s. If this second word is
executed as an instruction (by itself), it will execute as
a NOP.
The instruction set is highly orthogonal and is grouped
into four basic categories:
• Byte-oriented operations
• Bit-oriented operations
• Literal operations
All single-word instructions are executed in a single
instruction cycle, unless a conditional test is true or the
program counter is changed as a result of the instruc-
tion. In these cases, the execution takes two instruction
cycles with the additional instruction cycle(s) executed
as a NOP.
• Control operations
The PIC18 instruction set summary in Table 23-2 lists
byte-oriented, bit-oriented, literal and control opera-
tions. Table 23-1 shows the OPCODE field descriptions.
The double word instructions execute in two instruction
cycles.
Most byte-oriented instructions have three operands:
1. The file register (specified by ‘f’)
One instruction cycle consists of four oscillator periods.
Thus, for an oscillator frequency of 4 MHz, the normal
instruction execution time is 1 µs. If a conditional test is
true or the program counter is changed as a result of an
instruction, the instruction execution time is 2 µs. Two-
word branch instructions (if true) would take 3 µs.
2. The destination of the result
(specified by ‘d’)
3. The accessed memory
(specified by ‘a’)
The file register designator 'f' specifies which file
register is to be used by the instruction.
Figure 23-1 shows the general formats that the instruc-
tions can have.
The destination designator ‘d’ specifies where the
result of the operation is to be placed. If 'd' is zero, the
result is placed in the WREG register. If 'd' is one, the
result is placed in the file register specified in the
instruction.
All examples use the format ‘nnh’ to represent a hexa-
decimal number, where ‘h’ signifies a hexadecimal
digit.
The Instruction Set Summary, shown in Table 23-2,
lists the instructions recognized by the Microchip
Assembler (MPASMTM assembler). Section 23.2
“Instruction Set” provides a description of each
instruction.
All bit-oriented instructions have three operands:
1. The file register (specified by ‘f’)
2. The bit in the file register
(specified by ‘b’)
3. The accessed memory
(specified by ‘a’)
23.1 READ-MODIFY-WRITE OPERATIONS
Any instruction that specifies a file register as part of
the instruction performs a Read-Modify-Write (R-M-W)
operation. The register is read, the data is modified,
and the result is stored according to either the instruc-
tion or the destination designator ‘d’. A read operation
is performed on a register even if the instruction writes
to that register.
The bit field designator 'b' selects the number of the bit
affected by the operation, while the file register desig-
nator 'f' represents the number of the file in which the
bit is located.
The literal instructions may use some of the following
operands:
• A literal value to be loaded into a file register
(specified by ‘k’)
For example, a "BCF PORTB,1" instruction will read
PORTB, clear bit 1 of the data, then write the result
back to PORTB. The read operation would have the
unintended result that any condition that sets the RBIF
flag would be cleared. The R-M-W operation may also
copy the level of an input pin to its corresponding output
latch.
• The desired FSR register to load the literal value
into (specified by ‘f’)
• No operand required
(specified by ‘—’)
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TABLE 23-1: OPCODE FIELD DESCRIPTIONS
Field
Description
a
RAM access bit:
a = 0: RAM location in Access RAM (BSR register is ignored)
a = 1: RAM bank is specified by BSR register
bbb
BSR
d
Bit address within an 8-bit file register (0 to 7).
Bank Select Register. Used to select the current RAM bank.
Destination select bit:
d = 0: store result in WREG
d = 1: store result in file register f
dest
f
Destination either the WREG register or the specified register file location.
8-bit register file address (0x00 to 0xFF).
fs
12-bit register file address (0x000 to 0xFFF). This is the source address.
12-bit register file address (0x000 to 0xFFF). This is the destination address.
Literal field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value).
Label name.
fd
k
label
mm
The mode of the TBLPTR register for the table read and table write instructions.
Only used with table read and table write instructions:
*
No Change to register (such as TBLPTR with table reads and writes).
Post-Increment register (such as TBLPTR with table reads and writes).
Post-Decrement register (such as TBLPTR with table reads and writes).
Pre-Increment register (such as TBLPTR with table reads and writes).
*+
*-
+*
n
The relative address (2’s complement number) for relative branch instructions, or the direct address for Call/
Branch and Return instructions.
PRODH
PRODL
s
Product of Multiply high byte.
Product of Multiply low byte.
Fast Call/Return Mode Select bit:
s = 0: do not update into/from shadow registers
s = 1: certain registers loaded into/from shadow registers (Fast mode)
u
Unused or Unchanged.
WREG
x
Working register (accumulator).
Don't care (0or 1) .
The assembler will generate code with x = 0. It is the recommended form of use for compatibility with all
Microchip software tools.
TBLPTR
TABLAT
TOS
21-bit Table Pointer (points to a Program Memory location).
8-bit Table Latch.
Top-of-Stack.
PC
Program Counter.
PCL
Program Counter Low Byte.
Program Counter High Byte.
Program Counter High Byte Latch.
Program Counter Upper Byte Latch.
Global Interrupt Enable bit.
Watchdog Timer.
PCH
PCLATH
PCLATU
GIE
WDT
TO
Time-out bit.
PD
Power-down bit.
C, DC, Z, OV, N
ALU status bits Carry, Digit Carry, Zero, Overflow, Negative.
Optional.
[
]
)
(
Contents.
→
< >
∈
Assigned to.
Register bit field.
In the set of.
italics
User defined term (font is courier).
DS39616B-page 288
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FIGURE 23-1:
GENERAL FORMAT FOR INSTRUCTIONS
Byte-oriented file register operations
15 10
OPCODE f (FILE #)
Example Instruction
9
8
7
0
ADDWF MYREG, W, B
d
a
d = 0for result destination to be WREG register
d = 1for result destination to be file register (f)
a = 0to force Access Bank
a = 1for BSR to select bank
f = 8-bit file register address
Byte to Byte move operations (2-word)
15
12 11
0
0
OPCODE
f (Source FILE #)
MOVFF MYREG1, MYREG2
15
12 11
1111
f (Destination FILE #)
f = 12-bit file register address
Bit-oriented file register operations
15 12 11 9 8
OPCODE b (BIT #)
7
0
BSF MYREG, bit, B
a
f (FILE #)
b = 3-bit position of bit in file register (f)
a = 0to force Access Bank
a = 1for BSR to select bank
f = 8-bit file register address
Literal operations
15
8
7
0
MOVLW 0x7F
OPCODE
k (literal)
k = 8-bit immediate value
Control operations
CALL, GOTO and Branch operations
15
8 7
0
GOTO Label
OPCODE
12 11
n<7:0> (literal)
15
0
1111
n<19:8> (literal)
n = 20-bit immediate value
15
15
8
7
0
CALL MYFUNC
OPCODE
12 11
n<7:0> (literal)
S
0
n<19:8> (literal)
S = Fast bit
11 10
15
0
0
BRA MYFUNC
BC MYFUNC
OPCODE
n<10:0> (literal)
15
OPCODE
8 7
n<7:0> (literal)
2003 Microchip Technology Inc.
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PIC18F2331/2431/4331/4431
TABLE 23-2: PIC18FXXX INSTRUCTION SET
16-Bit Instruction Word
MSb LSb
Mnemonic,
Operands
Status
Affected
Description
Cycles
Notes
BYTE-ORIENTED FILE REGISTER OPERATIONS
ADDWF f, d, a Add WREG and f
ADDWFC f, d, a Add WREG and Carry bit to f
1
0010 01da ffff ffff C, DC, Z, OV, N 1, 2
0010 00da ffff ffff C, DC, Z, OV, N 1, 2
1
1
1
1
ANDWF
CLRF
COMF
f, d, a AND WREG with f
f, a Clear f
f, d, a Complement f
0001 01da ffff ffff Z, N
0110 101a ffff ffff Z
0001 11da ffff ffff Z, N
1,2
2
1, 2
4
CPFSEQ
CPFSGT
CPFSLT
DECF
DECFSZ
DCFSNZ
INCF
f, a
f, a
f, a
Compare f with WREG, skip = 1 (2 or 3) 0110 001a ffff ffff None
Compare f with WREG, skip > 1 (2 or 3) 0110 010a ffff ffff None
Compare f with WREG, skip < 1 (2 or 3) 0110 000a ffff ffff None
4
1, 2
f, d, a Decrement f
f, d, a Decrement f, Skip if 0
f, d, a Decrement f, Skip if Not 0
f, d, a Increment f
1
0000 01da ffff ffff C, DC, Z, OV, N 1, 2, 3, 4
1 (2 or 3) 0010 11da ffff ffff None
1 (2 or 3) 0100 11da ffff ffff None
1
1, 2, 3, 4
1, 2
0010 10da ffff ffff C, DC, Z, OV, N 1, 2, 3, 4
INCFSZ
INFSNZ
IORWF
MOVF
f, d, a Increment f, Skip if 0
f, d, a Increment f, Skip if Not 0
f, d, a Inclusive OR WREG with f
f, d, a Move f
fs, fd Move fs (source) to 1st word
fd (destination) 2nd word
1 (2 or 3) 0011 11da ffff ffff None
1 (2 or 3) 0100 10da ffff ffff None
4
1, 2
1, 2
1
1
1
2
0001 00da ffff ffff Z, N
0101 00da ffff ffff Z, N
1100 ffff ffff ffff None
1111 ffff ffff ffff
MOVFF
MOVWF
MULWF
NEGF
RLCF
RLNCF
RRCF
f, a
f, a
f, a
Move WREG to f
Multiply WREG with f
Negate f
1
1
1
1
1
1
1
1
1
0110 111a ffff ffff None
0000 001a ffff ffff None
0110 110a ffff ffff C, DC, Z, OV, N 1, 2
0011 01da ffff ffff C, Z, N
0100 01da ffff ffff Z, N
0011 00da ffff ffff C, Z, N
0100 00da ffff ffff Z, N
0110 100a ffff ffff None
f, d, a Rotate Left f through Carry
f, d, a Rotate Left f (No Carry)
f, d, a Rotate Right f through Carry
f, d, a Rotate Right f (No Carry)
1, 2
RRNCF
SETF
f, a
Set f
SUBFWB f, d, a Subtract f from WREG with
borrow
0101 01da ffff ffff C, DC, Z, OV, N 1, 2
SUBWF
f, d, a Subtract WREG from f
1
1
0101 11da ffff ffff C, DC, Z, OV, N
0101 10da ffff ffff C, DC, Z, OV, N 1, 2
SUBWFB f, d, a Subtract WREG from f with
borrow
SWAPF
TSTFSZ
XORWF
f, d, a Swap nibbles in f
f, a Test f, skip if 0
f, d, a Exclusive OR WREG with f
1
0011 10da ffff ffff None
4
1, 2
1 (2 or 3) 0110 011a ffff ffff None
1
0001 10da ffff ffff Z, N
BIT-ORIENTED FILE REGISTER OPERATIONS
BCF
BSF
BTFSC
BTFSS
BTG
f, b, a Bit Clear f
f, b, a Bit Set f
f, b, a Bit Test f, Skip if Clear
f, b, a Bit Test f, Skip if Set
f, d, a Bit Toggle f
1
1
1001 bbba ffff ffff None
1000 bbba ffff ffff None
1, 2
1, 2
3, 4
3, 4
1, 2
1 (2 or 3) 1011 bbba ffff ffff None
1 (2 or 3) 1010 bbba ffff ffff None
1
0111 bbba ffff ffff None
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be
that value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and
is driven low by an external device, the data will be written back with a ‘0’.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared
if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The
second cycle is executed as a NOP.
4: Some instructions are 2-word instructions. The second word of these instructions will be executed as a NOP,
unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures that
all program memory locations have a valid instruction.
5: If the table write starts the write cycle to internal memory, the write will continue until terminated.
DS39616B-page 290
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TABLE 23-2: PIC18FXXX INSTRUCTION SET (CONTINUED)
16-Bit Instruction Word
MSb LSb
Mnemonic,
Operands
Status
Affected
Description
Cycles
Notes
CONTROL OPERATIONS
BC
BN
n
n
n
n
n
n
n
n
Branch if Carry
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
2
1 (2)
1 (2)
1 (2)
2
1110 0010 nnnn nnnn None
1110 0110 nnnn nnnn None
1110 0011 nnnn nnnn None
1110 0111 nnnn nnnn None
1110 0101 nnnn nnnn None
1110 0001 nnnn nnnn None
1110 0100 nnnn nnnn None
1101 0nnn nnnn nnnn None
1110 0000 nnnn nnnn None
1110 110s kkkk kkkk None
1111 kkkk kkkk kkkk
Branch if Negative
Branch if Not Carry
Branch if Not Negative
Branch if Not Overflow
Branch if Not Zero
Branch if Overflow
Branch Unconditionally
Branch if Zero
BNC
BNN
BNOV
BNZ
BOV
BRA
BZ
n
n, s
CALL
Call subroutine 1st word
2nd word
CLRWDT
DAW
GOTO
—
—
n
Clear Watchdog Timer
Decimal Adjust WREG
Go to address 1st word
2nd word
1
1
2
0000 0000 0000 0100 TO, PD
0000 0000 0000 0111 C, DC
1110 1111 kkkk kkkk None
1111 kkkk kkkk kkkk
NOP
NOP
POP
PUSH
RCALL
RESET
RETFIE
—
—
—
—
n
No Operation
No Operation
Pop top of return stack (TOS)
Push top of return stack (TOS) 1
Relative Call
Software device Reset
Return from interrupt enable
1
1
1
0000 0000 0000 0000 None
1111 xxxx xxxx xxxx None
0000 0000 0000 0110 None
0000 0000 0000 0101 None
1101 1nnn nnnn nnnn None
0000 0000 1111 1111 All
0000 0000 0001 000s GIE/GIEH,
PEIE/GIEL
4
2
1
2
s
RETLW
RETURN
SLEEP
k
s
—
Return with literal in WREG
Return from Subroutine
Go into Standby mode
2
2
1
0000 1100 kkkk kkkk None
0000 0000 0001 001s None
0000 0000 0000 0011 TO, PD
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be
that value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and
is driven low by an external device, the data will be written back with a ‘0’.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared
if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The
second cycle is executed as a NOP.
4: Some instructions are 2-word instructions. The second word of these instructions will be executed as a NOP,
unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures that
all program memory locations have a valid instruction.
5: If the table write starts the write cycle to internal memory, the write will continue until terminated.
2003 Microchip Technology Inc.
Preliminary
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PIC18F2331/2431/4331/4431
TABLE 23-2: PIC18FXXX INSTRUCTION SET (CONTINUED)
16-Bit Instruction Word
Mnemonic,
Operands
Status
Affected
Description
Cycles
Notes
MSb
LSb
LITERAL OPERATIONS
ADDLW
ANDLW
IORLW
LFSR
k
k
k
f, k
Add literal and WREG
AND literal with WREG
Inclusive OR literal with WREG
Move literal (12-bit) 2nd word
to FSRx 1st word
Move literal to BSR<3:0>
Move literal to WREG
Multiply literal with WREG
Return with literal in WREG
Subtract WREG from literal
Exclusive OR literal with
WREG
1
0000 1111 kkkk
0000 1011 kkkk
0000 1001 kkkk
1110 1110 00ff
1111 0000 kkkk
0000 0001 0000
0000 1110 kkkk
0000 1101 kkkk
0000 1100 kkkk
0000 1000 kkkk
0000 1010 kkkk
kkkk C, DC, Z, OV, N
kkkk Z, N
kkkk Z, N
kkkk None
kkkk
kkkk None
kkkk None
kkkk None
kkkk None
kkkk C, DC, Z, OV, N
kkkk Z, N
1
1
2
MOVLB
MOVLW
MULLW
RETLW
SUBLW
XORLW
k
k
k
k
k
k
1
1
1
2
1
1
DATA MEMORY ↔ PROGRAM MEMORY OPERATIONS
TBLRD*
Table Read
2
0000 0000 0000
0000 0000 0000
0000 0000 0000
0000 0000 0000
0000 0000 0000
0000 0000 0000
0000 0000 0000
0000 0000 0000
1000 None
1001 None
1010 None
1011 None
1100 None
1101 None
1110 None
1111 None
TBLRD*+
TBLRD*-
TBLRD+*
TBLWT*
TBLWT*+
TBLWT*-
TBLWT+*
Table Read with post-increment
Table Read with post-decrement
Table Read with pre-increment
Table Write
Table Write with post-increment
Table Write with post-decrement
Table Write with pre-increment
2 (5)
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be
that value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and
is driven low by an external device, the data will be written back with a ‘0’.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared
if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The
second cycle is executed as a NOP.
4: Some instructions are 2-word instructions. The second word of these instructions will be executed as a NOP,
unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures that
all program memory locations have a valid instruction.
5: If the table write starts the write cycle to internal memory, the write will continue until terminated.
DS39616B-page 292
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23.2 Instruction Set
ADDLW
ADD literal to W
ADDWF
ADD W to f
Syntax:
[ label ] ADDLW
0 ≤ k ≤ 255
k
Syntax:
[ label ] ADDWF
f [,d [,a]]
Operands:
Operation:
Status Affected:
Encoding:
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
(W) + k → W
N, OV, C, DC, Z
Operation:
(W) + (f) → dest
0000
1111
kkkk
kkkk
Status Affected:
Encoding:
N, OV, C, DC, Z
Description:
The contents of W are added to the
8-bit literal ‘k’ and the result is
placed in W.
0010
01da
ffff
ffff
Description:
Add W to register ‘f’. If ‘d’ is 0, the
result is stored in W. If ‘d’ is 1, the
result is stored back in register ‘f’
(default). If ‘a’ is 0, the Access
Bank will be selected. If ‘a’ is 1, the
BSR is used.
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Words:
Cycles:
1
1
Decode
Read
literal ‘k’
Process
Data
Write to W
Q Cycle Activity:
Q1
ADDLW
0x15
Example:
Q2
Q3
Q4
Before Instruction
Decode
Read
register ‘f’
Process
Data
Write to
destination
W
=
0x10
After Instruction
W
=
0x25
ADDWF
REG, W
Example:
Before Instruction
W
REG
=
=
0x17
0xC2
After Instruction
W
REG
=
=
0xD9
0xC2
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ADDWFC
ADD W and Carry bit to f
ANDLW
AND literal with W
Syntax:
[ label ] ADDWFC
f [,d [,a]]
Syntax:
[ label ] ANDLW
0 ≤ k ≤ 255
k
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
Operation:
Status Affected:
Encoding:
(W) .AND. k → W
N, Z
Operation:
(W) + (f) + (C) → dest
0000
1011
kkkk
kkkk
Status Affected:
Encoding:
N, OV, C, DC, Z
Description:
The contents of W are ANDed with
the 8-bit literal ‘k’. The result is
placed in W.
0010
00da
ffff
ffff
Description:
Add W, the Carry Flag and data
memory location ‘f’. If ‘d’ is 0, the
result is placed in W. If ‘d’ is 1, the
result is placed in data memory loca-
tion ‘f’. If ‘a’ is 0, the Access Bank
will be selected. If ‘a’ is 1, the BSR
will not be overridden.
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read literal
‘k’
Process
Data
Write to W
Words:
Cycles:
1
1
ANDLW
0x5F
Example:
Q Cycle Activity:
Q1
Before Instruction
Q2
Q3
Q4
W
=
0xA3
0x03
Decode
Read
register 'f'
Process
Data
Write to
destination
After Instruction
W
=
ADDWFC
REG, W
Example:
Before Instruction
Carry bit =
1
REG
W
=
=
0x02
0x4D
After Instruction
Carry bit =
0
0x02
REG
=
W
=
0x50
DS39616B-page 294
Preliminary
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ANDWF
AND W with f
BC
Branch if Carry
[ label ] BC
Syntax:
[ label ] ANDWF
f [,d [,a]]
Syntax:
n
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
Operation:
-128 ≤ n ≤ 127
if carry bit is ‘1’
(PC) + 2 + 2n → PC
Operation:
(W) .AND. (f) → dest
Status Affected:
Encoding:
None
Status Affected:
Encoding:
N, Z
1110
0010
nnnn
nnnn
0001
01da
ffff
ffff
Description:
If the Carry bit is 1, then the
Description:
The contents of W are AND’ed with
register ‘f’. If ‘d’ is 0, the result is
stored in W. If ‘d’ is 1, the result is
stored back in register ‘f’ (default).
If ‘a’ is 0, the Access Bank will be
selected. If ‘a’ is 1, the BSR will not
be overridden (default).
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then a
two-cycle instruction.
Words:
Cycles:
1
1
Words:
Cycles:
1
1(2)
Q Cycle Activity:
Q1
Q Cycle Activity:
If Jump:
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Decode
Read
register 'f'
Process
Data
Write to
destination
Decode
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
ANDWF
REG, W
Example:
Before Instruction
If No Jump:
Q1
W
REG
=
=
0x17
0xC2
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
No
operation
After Instruction
W
REG
=
=
0x02
0xC2
HERE
BC JUMP
Example:
Before Instruction
PC
=
address (HERE)
After Instruction
If Carry
=
=
=
=
1;
PC
address (JUMP)
If Carry
PC
0;
address (HERE+2)
2003 Microchip Technology Inc.
Preliminary
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BCF
Bit Clear f
BN
Branch if Negative
[ label ] BN
Syntax:
[ label ] BCF f,b[,a]
Syntax:
n
Operands:
0 ≤ f ≤ 255
0 ≤ b ≤ 7
a ∈ [0,1]
Operands:
Operation:
-128 ≤ n ≤ 127
if negative bit is ‘1’
(PC) + 2 + 2n → PC
Operation:
0 → f<b>
Status Affected:
Encoding:
None
Status Affected:
Encoding:
None
1110
0110
nnnn
nnnn
1001
bbba
ffff
ffff
Description:
If the Negative bit is ‘1’, then the
program will branch.
Description:
Bit ‘b’ in register ‘f’ is cleared. If ‘a’
is 0, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then a
two-cycle instruction.
Words:
Cycles:
1
1
Words:
Cycles:
1
1(2)
Q Cycle Activity:
Q1
Q Cycle Activity:
If Jump:
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
Q1
Q2
Q3
Q4
register ‘f’
Decode
Read literal
‘n’
Process
Data
Write to PC
BCF
FLAG_REG,
7
Example:
No
operation
No
operation
No
operation
No
operation
Before Instruction
FLAG_REG = 0xC7
If No Jump:
Q1
After Instruction
Q2
Q3
Q4
FLAG_REG = 0x47
Decode
Read literal
‘n’
Process
Data
No
operation
HERE
BN Jump
Example:
Before Instruction
PC
=
address (HERE)
After Instruction
If Negative
=
=
=
=
1;
PC
address (Jump)
If Negative
PC
0;
address (HERE+2)
DS39616B-page 296
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BNC
Branch if Not Carry
BNN
Branch if Not Negative
Syntax:
[ label ] BNC
-128 ≤ n ≤ 127
if carry bit is ‘0’
n
Syntax:
[ label ] BNN
-128 ≤ n ≤ 127
n
Operands:
Operation:
Operands:
Operation:
if negative bit is ‘0’
(PC) + 2 + 2n → PC
(PC) + 2 + 2n → PC
Status Affected:
Encoding:
None
Status Affected:
Encoding:
None
1110
0011
nnnn
nnnn
1110
0111
nnnn
nnnn
Description:
If the Carry bit is ‘0’, then the
program will branch.
Description:
If the Negative bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then a
two-cycle instruction.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then a
two-cycle instruction.
Words:
Cycles:
1
Words:
Cycles:
1
1(2)
1(2)
Q Cycle Activity:
If Jump:
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to PC
Decode
Read literal
‘n’
Process
Data
Write to PC
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
If No Jump:
Q1
If No Jump:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
No
operation
Decode
Read literal
‘n’
Process
Data
No
operation
HERE
BNC Jump
HERE
BNN Jump
Example:
Example:
Before Instruction
Before Instruction
PC
=
address (HERE)
PC
=
address (HERE)
After Instruction
After Instruction
If Carry
=
=
=
=
0;
If Negative
=
=
=
=
0;
PC
address (Jump)
PC
address (Jump)
If Carry
PC
1;
If Negative
PC
1;
address (HERE+2)
address (HERE+2)
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BNOV
Branch if Not Overflow
BNZ
Branch if Not Zero
Syntax:
[ label ] BNOV
-128 ≤ n ≤ 127
n
Syntax:
[ label ] BNZ
-128 ≤ n ≤ 127
if zero bit is ‘0’
n
Operands:
Operation:
Operands:
Operation:
if overflow bit is ‘0’
(PC) + 2 + 2n → PC
(PC) + 2 + 2n → PC
Status Affected:
Encoding:
None
Status Affected:
Encoding:
None
1110
0101
nnnn
nnnn
1110
0001
nnnn
nnnn
Description:
If the Overflow bit is ‘0’, then the
program will branch.
Description:
If the Zero bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then a
two-cycle instruction.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then a
two-cycle instruction.
Words:
Cycles:
1
Words:
Cycles:
1
1(2)
1(2)
Q Cycle Activity:
If Jump:
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to PC
Decode
Read literal
‘n’
Process
Data
Write to PC
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
If No Jump:
Q1
If No Jump:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
No
operation
Decode
Read literal
‘n’
Process
Data
No
operation
HERE
BNOV Jump
HERE
BNZ Jump
Example:
Example:
Before Instruction
Before Instruction
PC
=
address (HERE)
PC
=
address (HERE)
After Instruction
After Instruction
If Overflow
=
=
=
=
0;
If Zero
=
=
=
=
0;
PC
address (Jump)
PC
address (Jump)
If Overflow
PC
1;
If Zero
PC
1;
address (HERE+2)
address (HERE+2)
DS39616B-page 298
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BRA
Unconditional Branch
[ label ] BRA
BSF
Bit Set f
Syntax:
n
Syntax:
[ label ] BSF f,b[,a]
Operands:
Operation:
Status Affected:
Encoding:
-1024 ≤ n ≤ 1023
(PC) + 2 + 2n → PC
None
Operands:
0 ≤ f ≤ 255
0 ≤ b ≤ 7
a ∈ [0,1]
Operation:
1 → f<b>
1101
0nnn
nnnn
nnnn
Status Affected:
Encoding:
None
Description:
Add the 2’s complement number
‘2n’ to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is a two-
cycle instruction.
1000
bbba
ffff
ffff
Description:
Bit ‘b’ in register 'f' is set. If ‘a’ is 0,
Access Bank will be selected, over-
riding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value.
Words:
Cycles:
1
2
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to PC
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
No
No
No
No
operation
operation
operation
operation
BSF
FLAG_REG, 7
Example:
Before Instruction
HERE
BRA Jump
Example:
FLAG_REG
=
=
0x0A
0x8A
Before Instruction
After Instruction
FLAG_REG
PC
=
=
address (HERE)
address (Jump)
After Instruction
PC
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BTFSC
Bit Test File, Skip if Clear
BTFSS
Bit Test File, Skip if Set
Syntax:
[ label ] BTFSC f,b[,a]
Syntax:
[ label ] BTFSS f,b[,a]
Operands:
0 ≤ f ≤ 255
0 ≤ b ≤ 7
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
0 ≤ b < 7
a ∈ [0,1]
Operation:
skip if (f<b>) = 0
Operation:
skip if (f<b>) = 1
Status Affected:
Encoding:
None
Status Affected:
Encoding:
None
1011
bbba
ffff
ffff
1010
bbba
ffff
ffff
Description:
If bit ‘b’ in register ‘f’ is 0, then the
next instruction is skipped.
Description:
If bit ‘b’ in register ‘f’ is 1, then the
next instruction is skipped.
If bit ‘b’ is 0, then the next instruction
fetched during the current instruction
execution is discarded, and a NOPis
executed instead, making this a two-
cycle instruction. If ‘a’ is 0, the
Access Bank will be selected, over-
riding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
If bit ‘b’ is 1, then the next instruction
fetched during the current instruc-
tion execution, is discarded and a
NOPis executed instead, making this
a two-cycle instruction. If ‘a’ is 0, the
Access Bank will be selected, over-
riding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
Cycles:
1
Words:
Cycles:
1
1(2)
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
Read
Process Data
No
Decode
Read
Process Data
No
register ‘f’
operation
register ‘f’
operation
If skip:
Q1
If skip:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
If skip and followed by 2-word instruction:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
HERE
FALSE
TRUE
BTFSC
:
:
FLAG, 1
HERE
FALSE
TRUE
BTFSS
:
:
FLAG, 1
Example:
Example:
Before Instruction
PC
Before Instruction
PC
=
address (HERE)
=
address (HERE)
After Instruction
After Instruction
If FLAG<1>
=
=
=
=
0;
If FLAG<1>
=
=
=
=
0;
PC
address (TRUE)
1;
PC
address (FALSE)
1;
If FLAG<1>
PC
If FLAG<1>
PC
address (FALSE)
address (TRUE)
DS39616B-page 300
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BTG
Bit Toggle f
BOV
Branch if Overflow
Syntax:
[ label ] BTG f,b[,a]
Syntax:
[ label ] BOV
-128 ≤ n ≤ 127
n
Operands:
0 ≤ f ≤ 255
0 ≤ b < 7
a ∈ [0,1]
Operands:
Operation:
if overflow bit is ‘1’
(PC) + 2 + 2n → PC
Operation:
(f<b>) → f<b>
Status Affected:
Encoding:
None
Status Affected:
Encoding:
None
1110
0100
nnnn
nnnn
0111
bbba
ffff
ffff
Description:
If the Overflow bit is ‘1’, then the
program will branch.
Description:
Bit ‘b’ in data memory location ‘f’ is
inverted. If ‘a’ is 0, the Access Bank
will be selected, overriding the BSR
value. If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then a
two-cycle instruction.
Words:
Cycles:
1
1
Words:
Cycles:
1
1(2)
Q Cycle Activity:
Q1
Q Cycle Activity:
If Jump:
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
Q1
Q2
Q3
Q4
register ‘f’
Decode
Read literal
‘n’
Process
Data
Write to PC
BTG
PORTC,
4
Example:
No
operation
No
operation
No
operation
No
operation
Before Instruction:
PORTC
=
0111 0101 [0x75]
If No Jump:
Q1
After Instruction:
Q2
Q3
Q4
PORTC
=
0110 0101 [0x65]
Decode
Read literal
‘n’
Process
Data
No
operation
HERE
BOV JUMP
Example:
Before Instruction
PC
=
address (HERE)
After Instruction
If Overflow
=
=
=
=
1;
PC
address (JUMP)
If Overflow
PC
0;
address (HERE+2)
2003 Microchip Technology Inc.
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BZ
Branch if Zero
[ label ] BZ
CALL
Subroutine Call
Syntax:
n
Syntax:
[ label ] CALL k [,s]
Operands:
Operation:
-128 ≤ n ≤ 127
Operands:
0 ≤ k ≤ 1048575
s ∈ [0,1]
if Zero bit is ‘1’
(PC) + 2 + 2n → PC
Operation:
(PC) + 4 → TOS,
k → PC<20:1>,
if s = 1
Status Affected:
Encoding:
None
1110
0000
nnnn
nnnn
(W) → WS,
(STATUS) → STATUSS,
(BSR) → BSRS
Description:
If the Zero bit is ‘1’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then a
two-cycle instruction.
Status Affected:
None
Encoding:
1st word (k<7:0>)
2nd word(k<19:8>)
1110
1111
110s
k kkk
kkkk
kkkk
7
0
8
k
kkk kkkk
19
Description:
Subroutine call of entire 2 Mbyte
memory range. First, return
address (PC+ 4) is pushed onto the
return stack. If ‘s’ = 1, the W,
Words:
Cycles:
1
1(2)
STATUS and BSR registers are
also pushed into their respective
shadow registers, WS, STATUSS
and BSRS. If ‘s’ = 0, no update
occurs (default). Then, the 20-bit
value ‘k’ is loaded into PC<20:1>.
CALLis a two-cycle instruction.
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
Words:
Cycles:
2
2
If No Jump:
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
No
operation
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read literal Push PC to Read literal
HERE
BZ Jump
Example:
‘k’<7:0>,
stack
‘k’<19:8>,
Write to PC
Before Instruction
PC
=
address (HERE)
No
No
No
No
operation
operation
operation
operation
After Instruction
If Zero
=
=
=
=
1;
PC
address (Jump)
HERE
CALL THERE,FAST
Example:
If Zero
PC
0;
address (HERE+2)
Before Instruction
PC
=
address (HERE)
After Instruction
PC
=
=
=
=
address (THERE)
TOS
WS
address (HERE + 4)
W
BSR
STATUS
BSRS
STATUSS=
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Preliminary
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CLRF
Clear f
CLRWDT
Clear Watchdog Timer
Syntax:
[ label ] CLRF f [,a]
Syntax:
[ label ] CLRWDT
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operands:
Operation:
None
000h → WDT,
000h → WDT postscaler,
1 → TO,
Operation:
000h → f
1 → Z
1 → PD
Status Affected:
Encoding:
Z
Status Affected:
Encoding:
TO, PD
0110
101a
ffff
ffff
0000
0000
0000
0100
Description:
Clears the contents of the specified
register. If ‘a’ is 0, the Access Bank
will be selected, overriding the BSR
value. If ‘a’ = 1, then the bank will
be selected as per the BSR value
(default).
Description:
CLRWDTinstruction resets the
Watchdog Timer. It also resets the
postscaler of the WDT. Status bits
TO and PD are set.
Words:
Cycles:
1
1
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
No
operation
Process
Data
No
operation
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
CLRWDT
Example:
CLRF
FLAG_REG
Example:
Before Instruction
WDT Counter
=
?
Before Instruction
FLAG_REG
=
=
0x5A
0x00
After Instruction
WDT Counter
WDT Postscaler
TO
=
=
=
=
0x00
After Instruction
FLAG_REG
0
1
1
PD
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COMF
Complement f
CPFSEQ
Compare f with W, skip if f = W
Syntax:
[ label ] COMF f [,d [,a]]
Syntax:
[ label ] CPFSEQ f [,a]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operation:
(f) – (W),
Operation:
(f) → dest
skip if (f) = (W)
(unsigned comparison)
Status Affected:
Encoding:
N, Z
Status Affected:
Encoding:
None
0001
11da
ffff
ffff
0110
001a
ffff
ffff
Description:
The contents of register ‘f’ are com-
plemented. If ‘d’ is 0, the result is
stored in W. If ‘d’ is 1, the result is
stored back in register ‘f’ (default).
If ‘a’ is 0, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Description:
Compares the contents of data
memory location ‘f’ to the contents
of W by performing an unsigned
subtraction.
If ‘f’ = W, then the fetched instruc-
tion is discarded and a NOPis
executed instead, making this a
two-cycle instruction. If ‘a’ is 0, the
Access Bank will be selected, over-
riding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Words:
Cycles:
1
Decode
Read
register ‘f’
Process
Data
Write to
1(2)
destination
Note: 3 cycles if skip and followed
by a 2-word instruction.
COMF
REG, W
Example:
Before Instruction
Q Cycle Activity:
Q1
REG
=
0x13
Q2
Q3
Q4
After Instruction
Decode
Read
register ‘f'’
Process
Data
No
operation
REG
=
0x13
W
=
0xEC
If skip:
Q1
Q2
Q3
Q4
No
No
No
No
operation
operation
operation
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
No
No
No
No
operation
operation
operation
operation
No
No
No
No
operation
operation
operation
operation
HERE
CPFSEQ REG
Example:
NEQUAL
EQUAL
:
:
Before Instruction
PC Address
=
HERE
W
REG
=
=
?
?
After Instruction
If REG
PC
=
=
W;
Address (EQUAL)
If REG
PC
≠
=
W;
Address (NEQUAL)
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CPFSGT
Compare f with W, skip if f > W
CPFSLT
Compare f with W, skip if f < W
Syntax:
[ label ] CPFSGT f [,a]
Syntax:
[ label ] CPFSLT f [,a]
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operation:
(f) − (W),
Operation:
(f) – (W),
skip if (f) > (W)
(unsigned comparison)
skip if (f) < (W)
(unsigned comparison)
Status Affected:
Encoding:
None
Status Affected:
Encoding:
None
0110
010a
ffff
ffff
0110
000a
ffff
ffff
Description:
Compares the contents of data
memory location ‘f’ to the contents
of the W by performing an
Description:
Compares the contents of data
memory location ‘f’ to the contents
of W by performing an unsigned
subtraction.
unsigned subtraction.
If the contents of ‘f’ are greater than
the contents of WREG, then the
fetched instruction is discarded and
a NOPis executed instead, making
this a two-cycle instruction. If ‘a’ is
0, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
If the contents of ‘f’ are less than
the contents of W, then the fetched
instruction is discarded and a NOP
is executed instead, making this a
two-cycle instruction. If ‘a’ is 0, the
Access Bank will be selected. If ‘a’
is 1, the BSR will not be overridden
(default).
Words:
Cycles:
1
1(2)
Words:
Cycles:
1
Note: 3 cycles if skip and followed
by a 2-word instruction.
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q Cycle Activity:
Q1
Decode
Read
register ‘f’
Process
Data
No
operation
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
No
operation
If skip:
Q1
Q2
Q3
Q4
If skip:
Q1
No
operation
No
operation
No
operation
No
operation
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
If skip and followed by 2-word instruction:
No
No
No
No
Q1
Q2
Q3
Q4
operation
operation
operation
operation
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
No
No
No
No
operation
operation
operation
operation
HERE
NLESS
LESS
CPFSLT REG
:
:
Example:
HERE
CPFSGT REG
Example:
NGREATER
GREATER
:
:
Before Instruction
PC
W
=
=
Address (HERE)
?
Before Instruction
After Instruction
PC
W
=
=
Address (HERE)
?
If REG
PC
If REG
PC
<
=
≥
=
W;
Address (LESS)
W;
Address (NLESS)
After Instruction
If REG
PC
>
=
W;
Address (GREATER)
If REG
PC
≤
=
W;
Address (NGREATER)
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DAW
Decimal Adjust W Register
DECF
Decrement f
Syntax:
[ label ] DAW
Syntax:
[ label ] DECF f [,d [,a]]
Operands:
Operation:
None
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
If [W<3:0> >9] or [DC = 1] then
(W<3:0>) + 6 → W<3:0>;
else
(W<3:0>) → W<3:0>;
Operation:
(f) – 1 → dest
Status Affected:
Encoding:
C, DC, N, OV, Z
0000
01da
ffff
ffff
If [W<7:4> >9] or [C = 1] then
(W<7:4>) + 6 → W<7:4>;
else
Description:
Decrement register ‘f’. If ‘d’ is 0, the
result is stored in W. If ‘d’ is 1, the
result is stored back in register ‘f’
(default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
(W<7:4>) → W<7:4>;
Status Affected:
Encoding:
C, DC
0000
0000
0000
0111
Description:
DAW adjusts the eight-bit value in
W, resulting from the earlier
addition of two variables (each in
packed BCD format) and produces
a correct packed BCD result. The
carry bit may be set by DAW
regardless of its setting prior to the
DAWinstruction.
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Words:
Cycles:
1
1
DECF
CNT,
Example:
Q Cycle Activity:
Q1
Before Instruction
Q2
Q3
Q4
CNT
Z
=
0x01
0
Decode
Read
register W
Process
Data
Write
W
=
After Instruction
DAW
Example1:
CNT
Z
=
=
0x00
1
Before Instruction
W
=
0xA5
C
DC
=
=
0
0
After Instruction
W
=
0x05
C
DC
=
=
1
0
Example 2:
Before Instruction
W
=
0xCE
C
DC
=
=
0
0
After Instruction
W
=
0x34
C
DC
=
=
1
0
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DECFSZ
Decrement f, skip if 0
DCFSNZ
Decrement f, skip if not 0
Syntax:
[ label ] DECFSZ f [,d [,a]]
Syntax:
[ label ] DCFSNZ f [,d [,a]]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) – 1 → dest,
skip if result = 0
Operation:
(f) – 1 → dest,
skip if result ≠ 0
Status Affected:
Encoding:
None
Status Affected:
Encoding:
None
0010
11da
ffff
ffff
0100
11da
ffff
ffff
Description:
The contents of register ‘f’ are dec-
remented. If ‘d’ is 0, the result is
placed in W. If ‘d’ is 1, the result is
placed back in register ‘f’ (default).
If the result is 0, the next instruc-
tion, which is already fetched, is
discarded, and a NOPis executed
instead, making it a two-cycle
instruction. If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Description:
The contents of register ‘f’ are dec-
remented. If ‘d’ is 0, the result is
placed in W. If ‘d’ is 1, the result is
placed back in register ‘f’ (default).
If the result is not 0, the next
instruction, which is already
fetched, is discarded, and a NOPis
executed instead, making it a two-
cycle instruction. If ‘a’ is 0, the
Access Bank will be selected,
overriding the BSR value. If ‘a’ = 1,
then the bank will be selected as
per the BSR value (default).
Words:
Cycles:
1
Words:
Cycles:
1
1(2)
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Decode
Read
register ‘f’
Process
Data
Write to
destination
If skip:
Q1
If skip:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
If skip and followed by 2-word instruction:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
HERE
DECFSZ
GOTO
CNT
LOOP
HERE
ZERO
NZERO
DCFSNZ TEMP
:
:
Example:
Example:
CONTINUE
Before Instruction
Before Instruction
TEMP
PC
=
Address (HERE)
=
?
After Instruction
After Instruction
CNT
=
=
=
≠
=
CNT - 1
0;
Address (CONTINUE)
0;
Address (HERE+2)
TEMP
If TEMP
PC
If TEMP
PC
=
=
=
≠
=
TEMP - 1,
0;
Address (ZERO)
0;
Address (NZERO)
If CNT
PC
If CNT
PC
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GOTO
Unconditional Branch
INCF
Increment f
Syntax:
[ label ] GOTO k
0 ≤ k ≤ 1048575
k → PC<20:1>
None
Syntax:
[ label ] INCF f [,d [,a]]
Operands:
Operation:
Status Affected:
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) + 1 → dest
Encoding:
1st word (k<7:0>)
2nd word(k<19:8>)
Status Affected:
Encoding:
C, DC, N, OV, Z
1110
1111
1111
k kkk
kkkk
kkkk
7
0
8
k
kkk kkkk
0010
10da
ffff
ffff
19
Description:
GOTOallows an unconditional
branch anywhere within entire
2 Mbyte memory range. The 20-bit
value ‘k’ is loaded into PC<20:1>.
GOTOis always a two-cycle
instruction.
Description:
The contents of register ‘f’ are
incremented. If ‘d’ is 0, the result is
placed in W. If ‘d’ is 1, the result is
placed back in register ‘f’ (default).
If ‘a’ is 0, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words:
Cycles:
2
2
Q Cycle Activity:
Q1
Words:
Cycles:
1
1
Q2
Q3
Q4
Decode
Read literal
‘k’<7:0>,
No
operation
Read literal
‘k’<19:8>,
Write to PC
Q Cycle Activity:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
Decode
Read
register ‘f’
Process
Data
Write to
destination
GOTO THERE
Example:
INCF
CNT,
Example:
After Instruction
Before Instruction
PC
=
Address (THERE)
CNT
=
0xFF
Z
=
=
=
0
?
?
C
DC
After Instruction
CNT
=
=
=
=
0x00
Z
1
1
1
C
DC
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INCFSZ
Increment f, skip if 0
INFSNZ
Increment f, skip if not 0
Syntax:
[ label ] INCFSZ f [,d [,a]]
Syntax:
[ label ] INFSNZ f [,d [,a]]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) + 1 → dest,
skip if result = 0
Operation:
(f) + 1 → dest,
skip if result ≠ 0
Status Affected:
Encoding:
None
Status Affected:
Encoding:
None
0011
11da
ffff
ffff
0100
10da
ffff
ffff
Description:
The contents of register ‘f’ are
incremented. If ‘d’ is 0, the result is
placed in W. If ‘d’ is 1, the result is
placed back in register ‘f’. (default)
If the result is 0, the next instruc-
tion, which is already fetched, is
discarded, and a NOPis executed
instead, making it a two-cycle
instruction. If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Description:
The contents of register ‘f’ are
incremented. If ‘d’ is 0, the result is
placed in W. If ‘d’ is 1, the result is
placed back in register ‘f’ (default).
If the result is not 0, the next
instruction, which is already
fetched, is discarded, and a NOPis
executed instead, making it a two-
cycle instruction. If ‘a’ is 0, the
Access Bank will be selected, over-
riding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
Cycles:
1
Words:
Cycles:
1
1(2)
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Decode
Read
register ‘f’
Process
Data
Write to
destination
If skip:
Q1
If skip:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
If skip and followed by 2-word instruction:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
No
No
No
No
No
No
No
No
operation
operation
operation
operation
operation
operation
operation
operation
HERE
NZERO
ZERO
INCFSZ
:
:
CNT
HERE
ZERO
NZERO
INFSNZ REG
Example:
Example:
Before Instruction
Before Instruction
PC
=
Address (HERE)
PC
=
Address (HERE)
After Instruction
After Instruction
CNT
If CNT
PC
If CNT
PC
=
=
=
≠
=
CNT + 1
REG
If REG
PC
If REG
PC
=
≠
=
=
=
REG + 1
0;
0;
Address (ZERO)
0;
Address (NZERO)
Address (NZERO)
0;
Address (ZERO)
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IORLW
Inclusive OR literal with W
IORWF
Inclusive OR W with f
Syntax:
[ label ] IORLW k
0 ≤ k ≤ 255
Syntax:
[ label ] IORWF f [,d [,a]]
Operands:
Operation:
Status Affected:
Encoding:
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
(W) .OR. k → W
N, Z
Operation:
(W) .OR. (f) → dest
0000
1001
kkkk
kkkk
Status Affected:
Encoding:
N, Z
Description:
The contents of W are OR’ed with
the eight-bit literal ‘k’. The result is
placed in W.
0001
00da
ffff
ffff
Description:
Inclusive OR W with register ‘f’. If
‘d’ is 0, the result is placed in W. If
‘d’ is 1, the result is placed back in
register ‘f’ (default). If ‘a’ is 0, the
Access Bank will be selected, over-
riding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to W
Words:
Cycles:
1
1
IORLW
0x35
Example:
Before Instruction
Q Cycle Activity:
Q1
W
=
0x9A
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
After Instruction
W
=
0xBF
IORWF RESULT, W
Example:
Before Instruction
RESULT =
0x13
0x91
W
=
After Instruction
RESULT =
0x13
0x93
W
=
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LFSR
Load FSR
MOVF
Move f
Syntax:
[ label ] LFSR f,k
Syntax:
[ label ] MOVF f [,d [,a]]
Operands:
0 ≤ f ≤ 2
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
0 ≤ k ≤ 4095
Operation:
k → FSRf
Operation:
f → dest
Status Affected:
Encoding:
None
Status Affected:
Encoding:
N, Z
1110
1111
1110
0000
00ff
k kkk
11
kkkk
k kkk
0101
00da
ffff
ffff
7
Description:
The 12-bit literal ‘k’ is loaded into
the file select register pointed to
by ‘f’.
Description:
The contents of register ‘f’ are
moved to a destination dependent
upon the status of ‘d’. If ‘d’ is 0, the
result is placed in W. If ‘d’ is 1, the
result is placed back in register ‘f’
(default). Location ‘f’ can be any-
where in the 256 byte bank. If ‘a’ is
0, the Access Bank will be
Words:
Cycles:
2
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Decode
Read literal
‘k’ MSB
Process
Data
Write
literal ‘k’
MSB to
FSRfH
Decode
Read literal
‘k’ LSB
Process
Data
Write literal
‘k’ to FSRfL
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
LFSR 2, 0x3AB
Example:
Q2
Q3
Q4
After Instruction
Decode
Read
register ‘f’
Process
Data
Write W
FSR2H
FSR2L
=
=
0x03
0xAB
MOVF
REG, W
Example:
Before Instruction
REG
W
=
=
0x22
0xFF
After Instruction
REG
W
=
=
0x22
0x22
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MOVFF
Move f to f
MOVLB
Move literal to low nibble in BSR
Syntax:
[ label ] MOVFF fs,fd
Syntax:
[ label ] MOVLB k
0 ≤ k ≤ 255
k → BSR
Operands:
0 ≤ fs ≤ 4095
0 ≤ fd ≤ 4095
Operands:
Operation:
Status Affected:
Encoding:
Operation:
(fs) → fd
None
Status Affected:
None
0000
0001
kkkk
kkkk
Encoding:
1st word (source)
2nd word (destin.)
Description:
The 8-bit literal ‘k’ is loaded into
the Bank Select Register (BSR).
1100
1111
ffff
ffff
ffff
ffff
ffffs
ffffd
Words:
Cycles:
1
1
Description:
The contents of source register ‘fs’
are moved to destination register
‘fd’. Location of source ‘fs’ can be
anywhere in the 4096 byte data
space (000h to FFFh) and location
of destination ‘fd’ can also be any-
where from 000h to FFFh.
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read literal
‘k’
Process
Data
Write
literal ‘k’ to
BSR
Either source or destination can be
W (a useful special situation).
MOVFFis particularly useful for
transferring a data memory location
to a peripheral register (such as the
transmit buffer or an I/O port).
MOVLB
5
Example:
Before Instruction
BSR register
=
=
0x02
0x05
After Instruction
BSR register
The MOVFFinstruction cannot use
the PCL, TOSU, TOSH or TOSL as
the destination register.
The MOVFFinstruction should not
be used to modify interrupt settings
while any interrupt is enabled (see
the note on page 91).
Words:
Cycles:
2
2 (3)
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
(src)
Process
Data
No
operation
Decode
No
operation
No
operation
Write
register ‘f’
(dest)
No dummy
read
MOVFF
REG1, REG2
Example:
Before Instruction
REG1
REG2
=
=
0x33
0x11
After Instruction
REG1
REG2
=
=
0x33,
0x33
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MOVLW
Move literal to W
MOVWF
Move W to f
Syntax:
[ label ] MOVLW k
0 ≤ k ≤ 255
k → W
Syntax:
[ label ] MOVWF f [,a]
Operands:
Operation:
Status Affected:
Encoding:
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operation:
(W) → f
None
Status Affected:
Encoding:
None
0000
1110
kkkk
kkkk
0110
111a
ffff
ffff
Description:
The eight-bit literal ‘k’ is loaded into
W.
Description:
Move data from W to register ‘f’.
Location ‘f’ can be anywhere in the
256 byte bank. If ‘a’ is 0, the
Access Bank will be selected, over-
riding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to W
Words:
Cycles:
1
1
MOVLW
0x5A
Example:
Q Cycle Activity:
Q1
After Instruction
Q2
Q3
Q4
W
=
0x5A
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
MOVWF
REG
Example:
Before Instruction
W
REG
=
=
0x4F
0xFF
After Instruction
W
REG
=
=
0x4F
0x4F
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MULLW
Multiply Literal with W
MULWF
Multiply W with f
Syntax:
[ label ] MULLW
0 ≤ k ≤ 255
k
Syntax:
[ label ] MULWF f [,a]
Operands:
Operation:
Status Affected:
Encoding:
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
(W) x k → PRODH:PRODL
Operation:
(W) x (f) → PRODH:PRODL
None
Status Affected:
Encoding:
None
0000
1101
kkkk
kkkk
0000
001a
ffff
ffff
Description:
An unsigned multiplication is
carried out between the contents
of W and the 8-bit literal ‘k’. The
16-bit result is placed in
PRODH:PRODL register pair.
PRODH contains the high byte.
W is unchanged.
None of the status flags are
affected.
Note that neither overflow nor
carry is possible in this opera-
tion. A zero result is possible but
not detected.
Description:
An unsigned multiplication is car-
ried out between the contents of
W and the register file location
‘f’. The 16-bit result is stored in
the PRODH:PRODL register
pair. PRODH contains the high
byte.
Both W and ‘f’ are unchanged.
None of the status flags are
affected.
Note that neither overflow nor
carry is possible in this opera-
tion. A zero result is possible but
not detected. If ‘a’ is 0, the
Access Bank will be selected,
overriding the BSR value. If
‘a’= 1, then the bank will be
selected as per the BSR value
(default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write
registers
PRODH:
PRODL
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
MULLW
0xC4
Example:
Q2
Q3
Q4
Before Instruction
Decode
Read
register ‘f’
Process
Data
Write
W
PRODH
PRODL
=
=
=
0xE2
registers
PRODH:
PRODL
?
?
After Instruction
W
=
0xE2
0xAD
0x08
MULWF
REG
Example:
PRODH
PRODL
=
=
Before Instruction
W
=
0xC4
REG
PRODH
PRODL
=
=
=
0xB5
?
?
After Instruction
W
=
0xC4
REG
PRODH
PRODL
=
=
=
0xB5
0x8A
0x94
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NEGF
Negate f
NOP
No Operation
Syntax:
[ label ] NEGF f [,a]
Syntax:
[ label ] NOP
None
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operands:
Operation:
Status Affected:
Encoding:
No operation
None
Operation:
( f ) + 1 → f
Status Affected:
Encoding:
N, OV, C, DC, Z
0000
1111
0000
xxxx
0000
xxxx
0000
xxxx
0110
110a
ffff
ffff
Description:
Words:
No operation.
Description:
Location ‘f’ is negated using two’s
complement. The result is placed in
the data memory location ‘f’. If ‘a’
is 0, the Access Bank will be
1
1
Cycles:
Q Cycle Activity:
Q1
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value.
Q2
No
Q3
No
Q4
Decode
No
operation
operation
operation
Words:
Cycles:
1
1
Example:
None.
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
NEGF
REG, 1
Example:
Before Instruction
REG
=
0011 1010 [0x3A]
1100 0110 [0xC6]
After Instruction
REG
=
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POP
Pop Top of Return Stack
PUSH
Push Top of Return Stack
Syntax:
[ label ] POP
None
Syntax:
[ label ] PUSH
None
Operands:
Operation:
Status Affected:
Encoding:
Operands:
Operation:
Status Affected:
Encoding:
(TOS) → bit bucket
None
(PC+2) → TOS
None
0000
0000
0000
0110
0000
0000
0000
0101
Description:
The TOS value is pulled off the
return stack and is discarded. The
TOS value then becomes the
previous value that was pushed
onto the return stack.
This instruction is provided to
enable the user to properly manage
the return stack to incorporate a
software stack.
Description:
The PC+2 is pushed onto the top of
the return stack. The previous TOS
value is pushed down on the stack.
This instruction allows to implement
a software stack by modifying TOS,
and then push it onto the return
stack.
Words:
Cycles:
1
1
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q Cycle Activity:
Q1
Decode
PUSH PC+2
onto return
stack
No
operation
No
operation
Q2
Q3
Q4
Decode
No
operation
POP TOS
value
No
operation
PUSH
Example:
POP
GOTO
Example:
Before Instruction
NEW
TOS
PC
=
=
0x00345A
0x000124
Before Instruction
TOS
=
=
0x0031A2
0x014332
After Instruction
Stack (1 level down)
PC
=
=
=
0x000126
0x000126
0x00345A
TOS
After Instruction
Stack (1 level down)
TOS
PC
=
=
0x014332
NEW
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RCALL
Relative Call
RESET
Reset
Syntax:
[ label ] RCALL
-1024 ≤ n ≤ 1023
(PC) + 2 → TOS,
n
Syntax:
[ label ] RESET
Operands:
Operation:
Operands:
Operation:
None
Reset all registers and flags that
are affected by a MCLR Reset.
(PC) + 2 + 2n → PC
Status Affected:
Encoding:
None
Status Affected:
Encoding:
All
1101
1nnn
nnnn
nnnn
0000
0000
1111
1111
Description:
Subroutine call with a jump up to
1K from the current location. First,
return address (PC+2) is pushed
onto the stack. Then, add the 2’s
complement number ‘2n’ to the PC.
Since the PC will have incremented
to fetch the next instruction, the
new address will be PC+2+2n. This
instruction is a two-cycle instruc-
tion.
Description:
This instruction provides a way to
execute a MCLR Reset in software.
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Start
reset
No
operation
No
operation
Words:
Cycles:
1
2
RESET
Example:
After Instruction
Registers =
Reset Value
Reset Value
Q Cycle Activity:
Q1
Flags*
=
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to PC
Push PC to
stack
No
No
No
No
operation
operation
operation
operation
HERE
RCALL
Jump
Example:
Before Instruction
PC
=
Address (HERE)
After Instruction
PC
=
Address (Jump)
Address (HERE+2)
TOS =
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RETFIE
Return from Interrupt
RETLW
Return Literal to W
Syntax:
[ label ] RETFIE [s]
s ∈ [0,1]
Syntax:
[ label ] RETLW k
0 ≤ k ≤ 255
Operands:
Operation:
Operands:
Operation:
(TOS) → PC,
1 → GIE/GIEH or PEIE/GIEL,
if s = 1
k → W,
(TOS) → PC,
PCLATU, PCLATH are unchanged
(WS) → W,
(STATUSS) → STATUS,
(BSRS) → BSR,
Status Affected:
Encoding:
None
0000
1100
kkkk
kkkk
PCLATU, PCLATH are unchanged.
Description:
W is loaded with the eight-bit literal
‘k’. The program counter is loaded
from the top of the stack (the return
address). The high address latch
(PCLATH) remains unchanged.
Status Affected:
Encoding:
GIE/GIEH, PEIE/GIEL.
0000
0000
0001
000s
Description:
Return from Interrupt. Stack is
popped and Top-of-Stack (TOS) is
loaded into the PC. Interrupts are
enabled by setting either the high
or low priority global interrupt
enable bit. If ‘s’ = 1, the contents of
the shadow registers WS,
STATUSS and BSRS are loaded
into their corresponding registers,
W, STATUS and BSR. If ‘s’ = 0, no
update of these registers occurs
(default).
Words:
Cycles:
1
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
pop PC from
stack, Write
to W
No
No
No
No
operation
operation
operation
operation
Words:
Cycles:
1
2
Example:
CALL TABLE ; W contains table
; offset value
Q Cycle Activity:
Q1
Q2
Q3
Q4
; W now has
; table value
Decode
No
operation
No
operation
pop PC from
stack
:
TABLE
ADDWF PCL ; W = offset
Set GIEH or
GIEL
RETLW k0
RETLW k1
:
; Begin table
;
No
operation
No
operation
No
operation
No
operation
:
RETLW kn
; End of table
RETFIE
1
Example:
After Interrupt
Before Instruction
PC
W
=
=
=
=
=
TOS
WS
W
=
0x07
BSR
STATUS
GIE/GIEH, PEIE/GIEL
BSRS
STATUSS
1
After Instruction
W
=
value of kn
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RETURN
Return from Subroutine
RLCF
Rotate Left f through Carry
Syntax:
[ label ] RETURN [s]
s ∈ [0,1]
Syntax:
[ label ] RLCF f [,d [,a]]
Operands:
Operation:
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
(TOS) → PC,
if s = 1
(WS) → W,
Operation:
(f<n>) → dest<n+1>,
(f<7>) → C,
(STATUSS) → STATUS,
(BSRS) → BSR,
PCLATU, PCLATH are unchanged
(C) → dest<0>
Status Affected:
Encoding:
C, N, Z
Status Affected:
Encoding:
None
0011
01da
ffff
ffff
0000
0000
0001
001s
Description:
The contents of register ‘f’ are
rotated one bit to the left through
the Carry Flag. If ‘d’ is 0, the result
is placed in W. If ‘d’ is 1, the result
is stored back in register ‘f’
(default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Description:
Return from subroutine. The stack
is popped and the top of the stack
(TOS) is loaded into the program
counter. If ‘s’= 1, the contents of the
shadow registers WS, STATUSS
and BSRS are loaded into their cor-
responding registers, W, STATUS
and BSR. If ‘s’ = 0, no update of
these registers occurs (default).
Words:
Cycles:
1
2
register f
C
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q Cycle Activity:
Q1
Decode
No
operation
Process
Data
pop PC from
stack
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
Decode
Read
register ‘f’
Process
Data
Write to
destination
RLCF
REG, W
Example:
RETURN
Example:
Before Instruction
REG
C
=
=
1110 0110
0
After Interrupt
PC = TOS
After Instruction
REG
=
1110 0110
W
C
=
=
1100 1100
1
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RLNCF
Rotate Left f (no carry)
RRCF
Rotate Right f through Carry
Syntax:
[ label ] RLNCF f [,d [,a]]
Syntax:
[ label ] RRCF f [,d [,a]]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f<n>) → dest<n+1>,
(f<7>) → dest<0>
Operation:
(f<n>) → dest<n-1>,
(f<0>) → C,
(C) → dest<7>
Status Affected:
Encoding:
N, Z
Status Affected:
Encoding:
C, N, Z
0100
01da
ffff
ffff
0011
00da
ffff
ffff
Description:
The contents of register ‘f’ are
rotated one bit to the left. If ‘d’ is 0,
the result is placed in W. If ‘d’ is 1,
the result is stored back in register
‘f’ (default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ is 1, then the
bank will be selected as per the
BSR value (default).
Description:
The contents of register ‘f’ are
rotated one bit to the right through
the Carry Flag. If ‘d’ is 0, the result
is placed in W. If ‘d’ is 1, the result
is placed back in register ‘f’
(default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ is 1, then the
bank will be selected as per the
BSR value (default).
register f
Words:
Cycles:
1
1
register f
C
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q Cycle Activity:
Q1
Decode
Read
register ‘f’
Process
Data
Write to
destination
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
RLNCF
REG
Example:
Before Instruction
RRCF
REG, W
Example:
REG
=
1010 1011
0101 0111
After Instruction
Before Instruction
REG
=
REG
C
=
=
1110 0110
0
After Instruction
REG
=
1110 0110
W
C
=
=
0111 0011
0
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RRNCF
Rotate Right f (no carry)
SETF
Set f
Syntax:
[ label ] RRNCF f [,d [,a]]
Syntax:
[ label ] SETF f [,a]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operation:
FFh → f
Operation:
(f<n>) → dest<n-1>,
(f<0>) → dest<7>
Status Affected:
Encoding:
None
0110
100a
ffff
ffff
Status Affected:
Encoding:
N, Z
Description:
The contents of the specified
register are set to FFh. If ‘a’ is 0,
the Access Bank will be selected,
overriding the BSR value. If ‘a’ is 1,
then the bank will be selected as
per the BSR value (default).
0100
00da
ffff
ffff
Description:
The contents of register ‘f’ are
rotated one bit to the right. If ‘d’ is
0, the result is placed in W. If ‘d’ is
1, the result is placed back in regis-
ter ‘f’ (default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ is 1, then the
bank will be selected as per the
BSR value (default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
register f
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
Words:
Cycles:
1
1
SETF
REG
Example:
Before Instruction
Q Cycle Activity:
Q1
REG
=
=
0x5A
0xFF
Q2
Q3
Q4
After Instruction
REG
Decode
Read
register ‘f’
Process
Data
Write to
destination
RRNCF
REG, 1, 0
Example 1:
Before Instruction
REG
=
1101 0111
1110 1011
RRNCF REG, W
After Instruction
REG
=
Example 2:
Before Instruction
W
REG
=
=
?
1101 0111
After Instruction
W
REG
=
=
1110 1011
1101 0111
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SLEEP
Enter Sleep mode
SUBFWB
Subtract f from W with borrow
Syntax:
[ label ] SLEEP
Syntax:
[ label ] SUBFWB f [,d [,a]]
Operands:
Operation:
None
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
00h → WDT,
0 → WDT postscaler,
1 → TO,
Operation:
(W) – (f) – (C) → dest
0 → PD
Status Affected:
Encoding:
N, OV, C, DC, Z
Status Affected:
Encoding:
TO, PD
0101
01da
ffff
ffff
0000
0000
0000
0011
Description:
Subtract register ‘f’ and carry flag
(borrow) from W (2’s complement
method). If ‘d’ is 0, the result is
stored in W. If ‘d’ is 1, the result is
stored in register ‘f’ (default). If ‘a’ is
0, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ is 1, then the bank will be
selected as per the BSR value
(default).
Description:
The power-down status bit (PD) is
cleared. The time-out status bit
(TO) is set. Watchdog Timer and
its postscaler are cleared.
The processor is put into Sleep
mode with the oscillator stopped.
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Words:
Cycles:
1
1
Q2
Q3
Q4
Decode
No
operation
Process
Data
Go to
sleep
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
SLEEP
Example:
Before Instruction
SUBFWB REG
Example 1:
TO
PD
=
?
=
?
Before Instruction
After Instruction
REG
W
C
=
=
=
0x03
0x02
0x01
TO
PD
=
=
1 †
0
After Instruction
† If WDT causes wake-up, this bit is cleared.
REG
=
0xFF
0x02
W
=
C
Z
N
=
=
=
0x00
0x00
0x01 ; result is negative
SUBFWB
REG, 0, 0
Example 2:
Before Instruction
REG
=
2
W
C
=
=
5
1
After Instruction
REG
W
=
=
2
3
C
Z
N
=
=
=
1
0
0
; result is positive
SUBFWB
REG, 1, 0
Example 3:
Before Instruction
REG
=
1
W
C
=
=
2
0
After Instruction
REG
W
=
=
0
2
C
Z
N
=
=
=
1
1
0
; result is zero
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SUBLW
Subtract W from literal
SUBWF
Syntax:
Subtract W from f
Syntax:
[ label ] SUBLW k
0 ≤ k ≤ 255
[ label ] SUBWF f [,d [,a]]
Operands:
Operation:
Status Affected:
Encoding:
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
k – (W) → W
N, OV, C, DC, Z
Operation:
(f) – (W) → dest
0000
1000
kkkk
kkkk
Status Affected:
Encoding:
N, OV, C, DC, Z
Description:
W is subtracted from the eight-bit
literal ‘k’. The result is placed in
W.
0101
11da
ffff
ffff
Description:
Subtract W from register ‘f’ (2’s
complement method). If ‘d’ is 0,
the result is stored in W. If ‘d’ is 1,
the result is stored back in regis-
ter ‘f’ (default). If = ‘a’ is 0, the
Access Bank will be selected,
overriding the BSR value. If ‘a’ is
1, then the bank will be selected
as per the BSR value (default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to W
SUBLW 0x02
Example 1:
Words:
Cycles:
1
1
Before Instruction
W
C
=
=
1
?
Q Cycle Activity:
Q1
Q2
Q3
Q4
After Instruction
Decode
Read
register ‘f’
Process
Data
Write to
destination
W
=
1
C
=
=
=
1
0
0
; result is positive
Z
SUBWF REG
Example 1:
N
SUBLW 0x02
Example 2:
Before Instruction
REG
W
C
=
=
=
3
2
?
Before Instruction
W
C
=
=
2
?
After Instruction
After Instruction
REG
W
=
=
1
2
W
=
0
C
Z
N
=
=
=
1
0
0
; result is positive
C
Z
N
=
=
=
1
1
0
; result is zero
SUBWF REG, W
Example 2:
SUBLW 0x02
Example 3:
Before Instruction
Before Instruction
REG
=
2
2
?
W
C
=
=
3
?
W
C
=
=
After Instruction
After Instruction
W
=
FF ; (2’s complement)
REG
=
2
0
C
Z
N
=
=
=
0
0
1
; result is negative
W
=
C
Z
N
=
=
=
1
1
0
; result is zero
SUBWF REG
Example 3:
Before Instruction
REG
=
0x01
W
C
=
=
0x02
?
After Instruction
REG
W
=
=
0xFFh ;(2’s complement)
0x02
C
Z
N
=
=
=
0x00 ; result is negative
0x00
0x01
2003 Microchip Technology Inc.
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SUBWFB
Syntax:
Subtract W from f with Borrow
SUBWFB REG, 1, 0
Example 1:
Before Instruction
[ label ] SUBWFB f [,d [,a]]
REG
W
C
=
=
=
0x19
0x0D
0x01
(0001 1001)
(0000 1101)
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
After Instruction
REG
W
C
Z
N
=
=
=
=
=
0x0C
0x0D
(0000 1011)
(0000 1101)
Operation:
(f) – (W) – (C) → dest
Status Affected: N, OV, C, DC, Z
0x01
0x00
0x00
Encoding:
0101
10da
ffff
ffff
; result is positive
Description:
Subtract W and the carry flag (bor-
row) from register ‘f’ (2’s complement
method). If ‘d’ is 0, the result is stored
in W. If ‘d’ is 1, the result is stored
back in register ‘f’ (default). If ‘a’ is 0,
the Access Bank will be selected,
overriding the BSR value. If ‘a’ is 1,
then the bank will be selected as per
the BSR value (default).
SUBWFB REG, 0, 0
Example 2:
Before Instruction
REG
W
C
=
=
=
0x1B
0x1A
0x00
(0001 1011)
(0001 1010)
After Instruction
REG
W
C
Z
N
=
=
=
=
=
0x1B
0x00
(0001 1011)
0x01
0x01
0x00
; result is zero
Words:
Cycles:
1
1
SUBWFB REG, 1, 0
Example 3:
Q Cycle Activity:
Q1
Before Instruction
REG
=
0x03
0x0E
0x01
(0000 0011)
(0000 1101)
Q2
Q3
Q4
W
C
=
=
Decode
Read
register ‘f’
Process
Data
Write to
destination
After Instruction
REG
=
0xF5
0x0E
(1111 0100)
; [2’s comp]
(0000 1101)
W
=
C
Z
N
=
=
=
0x00
0x00
0x01
; result is negative
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SWAPF
Swap f
Syntax:
[ label ] SWAPF f [,d [,a]]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f<3:0>) → dest<7:4>,
(f<7:4>) → dest<3:0>
Status Affected:
Encoding:
None
0011
10da
ffff
ffff
Description:
The upper and lower nibbles of reg-
ister ‘f’ are exchanged. If ‘d’ is 0,
the result is placed in W. If ‘d’ is 1,
the result is placed in register ‘f’
(default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ is 1, then the
bank will be selected as per the
BSR value (default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
SWAPF
REG
Example:
Before Instruction
REG
=
0x53
0x35
After Instruction
REG
=
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TBLRD
Table Read
TBLRD
Table Read (cont’d)
TBLRD *+ ;
Syntax:
[ label ] TBLRD ( *; *+; *-; +*)
Example1:
Operands:
Operation:
None
Before Instruction
TABLAT
TBLPTR
MEMORY(0x00A356)
=
=
=
0x55
0x00A356
0x34
if TBLRD *,
(Prog Mem (TBLPTR)) → TABLAT;
TBLPTR - No Change;
if TBLRD *+,
(Prog Mem (TBLPTR)) → TABLAT;
(TBLPTR) +1 → TBLPTR;
if TBLRD *-,
After Instruction
TABLAT
TBLPTR
=
=
0x34
0x00A357
TBLRD +* ;
Example2:
(Prog Mem (TBLPTR)) → TABLAT;
(TBLPTR) -1 → TBLPTR;
if TBLRD +*,
(TBLPTR) +1 → TBLPTR;
(Prog Mem (TBLPTR)) → TABLAT;
Before Instruction
TABLAT
TBLPTR
=
=
=
=
0xAA
0x01A357
0x12
MEMORY(0x01A357)
MEMORY(0x01A358)
0x34
After Instruction
Status Affected:None
TABLAT
TBLPTR
=
=
0x34
0x01A358
0000
0000
0000
10nn
nn=0 *
=1 *+
=2 *-
=3 +*
Encoding:
Description:
This instruction is used to read the
contents of Program Memory (P.M.). To
address the program memory, a
pointer called Table Pointer (TBLPTR)
is used.
The TBLPTR (a 21-bit pointer) points
to each byte in the program memory.
TBLPTR has a 2 Mbyte address range.
TBLPTR[0] = 0:Least Significant
Byte of Program
Memory Word
TBLPTR[0] = 1:Most Significant
Byte of Program
Memory Word
The TBLRDinstruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Words:
Cycles:
1
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
No
No
No
operation
operation
operation
No
No operation
No
No operation
operation (Read Program operation (Write TABLAT)
Memory)
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TBLWT
Table Write
TBLWT Table Write (Continued)
Syntax:
[ label ]
TBLWT ( *; *+; *-; +*)
Words: 1
Cycles: 2
Q Cycle Activity:
Q1
Operands:
Operation:
None
if TBLWT*,
(TABLAT) → Holding Register;
TBLPTR - No Change;
if TBLWT*+,
Q2
Q3
Q4
Decode
No
No
No
operation
operation
operation
(TABLAT) → Holding Register;
(TBLPTR) +1 → TBLPTR;
if TBLWT*-,
(TABLAT) → Holding Register;
(TBLPTR) -1 → TBLPTR;
if TBLWT+*,
No
operation
No
operation
(Read
No
operation
No
operation
(Write to
Holding
Register )
TABLAT)
(TBLPTR) +1 → TBLPTR;
(TABLAT) → Holding Register;
Example1:
TBLWT *+;
Before Instruction
Status Affected: None
TABLAT
TBLPTR
=
=
0x55
0000
0000
0000
11nn
nn=0 *
=1 *+
=2 *-
=3 +*
Encoding:
0x00A356
HOLDING REGISTER
(0x00A356)
=
0xFF
After Instructions (table write completion)
TABLAT
TBLPTR
HOLDING REGISTER
(0x00A356)
=
=
0x55
0x00A357
Description:
This instruction uses the 3 LSBs of
TBLPTR to determine which of the 8
holding registers the TABLAT is written
to. The holding registers are used to
program the contents of Program
Memory (P.M.). (Refer to Section 6.0
“Flash Program Memory” for addi-
tional details on programming Flash
memory.)
=
0x55
Example 2:
TBLWT +*;
Before Instruction
TABLAT
TBLPTR
HOLDING REGISTER
(0x01389A)
HOLDING REGISTER
(0x01389B)
=
=
0x34
0x01389A
=
=
0xFF
0xFF
The TBLPTR (a 21-bit pointer) points
to each byte in the program memory.
TBLPTR has a 2 MBtye address
range. The LSb of the TBLPTR selects
which byte of the program memory
location to access.
After Instruction (table write completion)
TABLAT
=
0x34
TBLPTR
=
0x01389B
HOLDING REGISTER
(0x01389A)
=
=
0xFF
0x34
HOLDING REGISTER
(0x01389B)
TBLPTR[0] = 0:Least Significant
Byte of Program
Memory Word
TBLPTR[0] = 1:Most Significant
Byte of Program
Memory Word
The TBLWT instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
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TSTFSZ
Test f, skip if 0
XORLW
Exclusive OR literal with W
Syntax:
[ label ] TSTFSZ f [,a]
Syntax:
[ label ] XORLW k
0 ≤ k ≤ 255
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operands:
Operation:
Status Affected:
Encoding:
(W) .XOR. k → W
N, Z
Operation:
skip if f = 0
Status Affected:
Encoding:
None
0000
1010
kkkk
kkkk
0110
011a
ffff
ffff
Description:
The contents of W are XORed
with the 8-bit literal ‘k’. The result
is placed in W.
Description:
If ‘f’ = 0, the next instruction,
fetched during the current instruc-
tion execution, is discarded and a
NOPis executed, making this a two-
cycle instruction. If ‘a’ is 0, the
Access Bank will be selected, over-
riding the BSR value. If ‘a’ is 1,
then the bank will be selected as
per the BSR value (default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to W
Words:
Cycles:
1
1(2)
Example:
XORLW 0xAF
= 0xB5
Note: 3 cycles if skip and followed
by a 2-word instruction.
Before Instruction
W
Q Cycle Activity:
Q1
After Instruction
Q2
Q3
Q4
W
=
0x1A
Decode
Read
register ‘f’
Process
Data
No
operation
If skip:
Q1
Q2
Q3
Q4
No
No
No
No
operation
operation
operation
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
No
No
No
No
operation
operation
operation
operation
No
No
No
No
operation
operation
operation
operation
HERE
NZERO
ZERO
TSTFSZ CNT
:
Example:
:
Before Instruction
PC = Address (HERE)
After Instruction
If CNT
=
=
≠
=
0x00,
PC
Address (ZERO)
0x00,
If CNT
PC
Address (NZERO)
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XORWF
Exclusive OR W with f
Syntax:
[ label ] XORWF f [,d [,a]]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(W) .XOR. (f) → dest
Status Affected:
Encoding:
N, Z
0001
10da
ffff
ffff
Description:
Exclusive OR the contents of W
with register ‘f’. If ‘d’ is 0, the result
is stored in W. If ‘d’ is 1, the result
is stored back in the register ‘f'
(default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ is 1, then the
bank will be selected as per the
BSR value (default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
XORWF
REG
Example:
Before Instruction
REG
W
=
=
0xAF
0xB5
After Instruction
REG
W
=
=
0x1A
0xB5
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NOTES:
DS39616B-page 330
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24.1 MPLAB Integrated Development
Environment Software
24.0 DEVELOPMENT SUPPORT
The PICmicro® microcontrollers are supported with a
full range of hardware and software development tools:
The MPLAB IDE software brings an ease of software
development previously unseen in the 8/16-bit micro-
controller market. The MPLAB IDE is a Windows®
based application that contains:
• Integrated Development Environment
- MPLAB® IDE Software
• Assemblers/Compilers/Linkers
- MPASMTM Assembler
• An interface to debugging tools
- simulator
- MPLAB C17 and MPLAB C18 C Compilers
- MPLINKTM Object Linker/
MPLIBTM Object Librarian
- programmer (sold separately)
- emulator (sold separately)
- in-circuit debugger (sold separately)
• A full-featured editor with color coded context
• A multiple project manager
- MPLAB C30 C Compiler
- MPLAB ASM30 Assembler/Linker/Library
• Simulators
• Customizable data windows with direct edit of
contents
- MPLAB SIM Software Simulator
- MPLAB dsPIC30 Software Simulator
• Emulators
• High level source code debugging
• Mouse over variable inspection
• Extensive on-line help
- MPLAB ICE 2000 In-Circuit Emulator
- MPLAB ICE 4000 In-Circuit Emulator
• In-Circuit Debugger
The MPLAB IDE allows you to:
• Edit your source files (either assembly or C)
- MPLAB ICD 2
• One touch assemble (or compile) and download
to PICmicro emulator and simulator tools
(automatically updates all project information)
• Device Programmers
- PRO MATE® II Universal Device Programmer
- PICSTART® Plus Development Programmer
• Low Cost Demonstration Boards
- PICDEMTM 1 Demonstration Board
- PICDEM.netTM Demonstration Board
- PICDEM 2 Plus Demonstration Board
- PICDEM 3 Demonstration Board
- PICDEM 4 Demonstration Board
- PICDEM 17 Demonstration Board
- PICDEM 18R Demonstration Board
- PICDEM LIN Demonstration Board
- PICDEM USB Demonstration Board
• Evaluation Kits
• Debug using:
- source files (assembly or C)
- absolute listing file (mixed assembly and C)
- machine code
MPLAB IDE supports multiple debugging tools in a
single development paradigm, from the cost effective
simulators, through low cost in-circuit debuggers, to
full-featured emulators. This eliminates the learning
curve when upgrading to tools with increasing flexibility
and power.
24.2 MPASM Assembler
®
- KEELOQ
The MPASM assembler is a full-featured, universal
macro assembler for all PICmicro MCUs.
- PICDEM MSC
- microID®
- CAN
The MPASM assembler generates relocatable object
files for the MPLINK object linker, Intel® standard HEX
files, MAP files to detail memory usage and symbol ref-
erence, absolute LST files that contain source lines and
generated machine code and COFF files for
debugging.
- PowerSmart®
- Analog
The MPASM assembler features include:
• Integration into MPLAB IDE projects
• User defined macros to streamline assembly code
• Conditional assembly for multi-purpose source
files
• Directives that allow complete control over the
assembly process
2003 Microchip Technology Inc.
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24.3 MPLAB C17 and MPLAB C18
C Compilers
24.6 MPLAB ASM30 Assembler, Linker,
and Librarian
The MPLAB C17 and MPLAB C18 Code Development
MPLAB ASM30 assembler produces relocatable
machine code from symbolic assembly language for
dsPIC30F devices. MPLAB C30 compiler uses the
assembler to produce it’s object file. The assembler
generates relocatable object files that can then be
archived or linked with other relocatable object files and
archives to create an executable file. Notable features
of the assembler include:
Systems are complete ANSI
C
compilers for
Microchip’s PIC17CXXX and PIC18CXXX family of
microcontrollers. These compilers provide powerful
integration capabilities, superior code optimization and
ease of use not found with other compilers.
For easy source level debugging, the compilers provide
symbol information that is optimized to the MPLAB IDE
debugger.
• Support for the entire dsPIC30F instruction set
• Support for fixed-point and floating-point data
• Command line interface
24.4 MPLINK Object Linker/
MPLIB Object Librarian
• Rich directive set
• Flexible macro language
The MPLINK object linker combines relocatable
objects created by the MPASM assembler and the
MPLAB C17 and MPLAB C18 C compilers. It can link
relocatable objects from pre-compiled libraries, using
directives from a linker script.
• MPLAB IDE compatibility
24.7 MPLAB SIM Software Simulator
The MPLAB SIM software simulator allows code devel-
opment in a PC hosted environment by simulating the
PICmicro series microcontrollers on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a file, or user defined key press, to any pin. The execu-
tion can be performed in Single-step, Execute-Until-
Break or Trace mode.
The MPLIB object librarian manages the creation and
modification of library files of pre-compiled code. When
a routine from a library is called from a source file, only
the modules that contain that routine will be linked in
with the application. This allows large libraries to be
used efficiently in many different applications.
The object linker/library features include:
• Efficient linking of single libraries instead of many
smaller files
The MPLAB SIM simulator fully supports symbolic
debugging using the MPLAB C17 and MPLAB C18
C Compilers, as well as the MPASM assembler. The
software simulator offers the flexibility to develop and
debug code outside of the laboratory environment,
making it an excellent, economical software
development tool.
• Enhanced code maintainability by grouping
related modules together
• Flexible creation of libraries with easy module
listing, replacement, deletion and extraction
24.5 MPLAB C30 C Compiler
24.8 MPLAB SIM30 Software Simulator
The MPLAB C30 C compiler is a full-featured, ANSI
compliant, optimizing compiler that translates standard
ANSI C programs into dsPIC30F assembly language
source. The compiler also supports many command-
line options and language extensions to take full
advantage of the dsPIC30F device hardware capabili-
ties, and afford fine control of the compiler code
generator.
The MPLAB SIM30 software simulator allows code
development in a PC hosted environment by simulating
the dsPIC30F series microcontrollers on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a file, or user defined key press, to any of the pins.
The MPLAB SIM30 simulator fully supports symbolic
debugging using the MPLAB C30 C Compiler and
MPLAB ASM30 assembler. The simulator runs in either
a Command Line mode for automated tasks, or from
MPLAB IDE. This high-speed simulator is designed to
debug, analyze and optimize time intensive DSP
routines.
MPLAB C30 is distributed with a complete ANSI C
standard library. All library functions have been vali-
dated and conform to the ANSI C library standard. The
library includes functions for string manipulation,
dynamic memory allocation, data conversion, time-
keeping, and math functions (trigonometric, exponen-
tial and hyperbolic). The compiler provides symbolic
information for high level source debugging with the
MPLAB IDE.
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24.9 MPLAB ICE 2000
High Performance Universal
In-Circuit Emulator
24.11 MPLAB ICD 2 In-Circuit Debugger
Microchip’s In-Circuit Debugger, MPLAB ICD 2, is a
powerful, low cost, run-time development tool,
connecting to the host PC via an RS-232 or high speed
The MPLAB ICE 2000 universal in-circuit emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for
PICmicro microcontrollers. Software control of the
MPLAB ICE 2000 in-circuit emulator is advanced by
the MPLAB Integrated Development Environment,
which allows editing, building, downloading and source
debugging from a single environment.
USB interface. This tool is based on the Flash
PICmicro MCUs and can be used to develop for these
and other PICmicro microcontrollers. The MPLAB
ICD 2 utilizes the in-circuit debugging capability built
into the Flash devices. This feature, along with
Microchip’s In-Circuit Serial ProgrammingTM (ICSPTM
)
protocol, offers cost effective in-circuit Flash debugging
from the graphical user interface of the MPLAB Inte-
grated Development Environment. This enables a
designer to develop and debug source code by setting
breakpoints, single-stepping and watching variables,
CPU status and peripheral registers. Running at full
speed enables testing hardware and applications in
real-time. MPLAB ICD 2 also serves as a development
programmer for selected PICmicro devices.
The MPLAB ICE 2000 is a full-featured emulator sys-
tem with enhanced trace, trigger and data monitoring
features. Interchangeable processor modules allow the
system to be easily reconfigured for emulation of differ-
ent processors. The universal architecture of the
MPLAB ICE in-circuit emulator allows expansion to
support new PICmicro microcontrollers.
The MPLAB ICE 2000 in-circuit emulator system has
been designed as a real-time emulation system with
advanced features that are typically found on more
expensive development tools. The PC platform and
Microsoft® Windows 32-bit operating system were
chosen to best make these features available in a
simple, unified application.
24.12 PRO MATE II Universal Device
Programmer
The PRO MATE II is a universal, CE compliant device
programmer with programmable voltage verification at
VDDMIN and VDDMAX for maximum reliability. It features
an LCD display for instructions and error messages
and a modular detachable socket assembly to support
various package types. In Stand-alone mode, the
PRO MATE II device programmer can read, verify, and
program PICmicro devices without a PC connection. It
can also set code protection in this mode.
24.10 MPLAB ICE 4000
High Performance Universal
In-Circuit Emulator
The MPLAB ICE 4000 universal in-circuit emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for high-
end PICmicro microcontrollers. Software control of the
MPLAB ICE in-circuit emulator is provided by the
MPLAB Integrated Development Environment, which
allows editing, building, downloading and source
debugging from a single environment.
24.13 PICSTART Plus Development
Programmer
The PICSTART Plus development programmer is an
easy-to-use, low cost, prototype programmer. It con-
nects to the PC via a COM (RS-232) port. MPLAB
Integrated Development Environment software makes
using the programmer simple and efficient. The
PICSTART Plus development programmer supports
most PICmicro devices up to 40 pins. Larger pin count
devices, such as the PIC16C92X and PIC17C76X,
may be supported with an adapter socket. The
PICSTART Plus development programmer is CE
compliant.
The MPLAB ICD 4000 is a premium emulator system,
providing the features of MPLAB ICE 2000, but with
increased emulation memory and high speed perfor-
mance for dsPIC30F and PIC18XXXX devices. Its
advanced emulator features include complex triggering
and timing, up to 2 Mb of emulation memory, and the
ability to view variables in real-time.
The MPLAB ICE 4000 in-circuit emulator system has
been designed as a real-time emulation system with
advanced features that are typically found on more
expensive development tools. The PC platform and
Microsoft Windows 32-bit operating system were cho-
sen to best make these features available in a simple,
unified application.
2003 Microchip Technology Inc.
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24.14 PICDEM 1 PICmicro
Demonstration Board
24.17 PICDEM 3 PIC16C92X
Demonstration Board
The PICDEM 1 demonstration board demonstrates the
capabilities of the PIC16C5X (PIC16C54 to
PIC16C58A), PIC16C61, PIC16C62X, PIC16C71,
PIC16C8X, PIC17C42, PIC17C43 and PIC17C44. All
necessary hardware and software is included to run
basic demo programs. The sample microcontrollers
provided with the PICDEM 1 demonstration board can
be programmed with a PRO MATE II device program-
mer, or a PICSTART Plus development programmer.
The PICDEM 1 demonstration board can be connected
to the MPLAB ICE in-circuit emulator for testing. A pro-
totype area extends the circuitry for additional applica-
tion components. Features include an RS-232
interface, a potentiometer for simulated analog input,
push button switches and eight LEDs.
The PICDEM 3 demonstration board supports the
PIC16C923 and PIC16C924 in the PLCC package. All
the necessary hardware and software is included to run
the demonstration programs.
24.18 PICDEM 4 8/14/18-Pin
Demonstration Board
The PICDEM 4 can be used to demonstrate the capa-
bilities of the 8-, 14-, and 18-pin PIC16XXXX and
PIC18XXXX MCUs, including the PIC16F818/819,
PIC16F87/88, PIC16F62XA and the PIC18F1320 fam-
ily of microcontrollers. PICDEM 4 is intended to show-
case the many features of these low pin count parts,
including LIN and Motor Control using ECCP. Special
provisions are made for low-power operation with the
supercapacitor circuit, and jumpers allow on-board
hardware to be disabled to eliminate current draw in
this mode. Included on the demo board are provisions
for Crystal, RC or Canned Oscillator modes, a five volt
regulator for use with a nine volt wall adapter or battery,
DB-9 RS-232 interface, ICD connector for program-
ming via ICSP and development with MPLAB ICD 2,
2x16 liquid crystal display, PCB footprints for H-Bridge
motor driver, LIN transceiver and EEPROM. Also
included are: header for expansion, eight LEDs, four
potentiometers, three push buttons and a prototyping
area. Included with the kit is a PIC16F627A and a
PIC18F1320. Tutorial firmware is included along with
the User’s Guide.
24.15 PICDEM.net Internet/Ethernet
Demonstration Board
The PICDEM.net demonstration board is an Internet/
Ethernet demonstration board using the PIC18F452
microcontroller and TCP/IP firmware. The board
supports any 40-pin DIP device that conforms to the
standard pinout used by the PIC16F877 or
PIC18C452. This kit features a user friendly TCP/IP
stack, web server with HTML, a 24L256 Serial
EEPROM for Xmodem download to web pages into
Serial EEPROM, ICSP/MPLAB ICD 2 interface con-
nector, an Ethernet interface, RS-232 interface, and a
16 x 2 LCD display. Also included is the book and
CD-ROM “TCP/IP Lean, Web Servers for Embedded
Systems,” by Jeremy Bentham
24.19 PICDEM 17 Demonstration Board
The PICDEM 17 demonstration board is an evaluation
board that demonstrates the capabilities of several
Microchip microcontrollers, including PIC17C752,
PIC17C756A, PIC17C762 and PIC17C766. A pro-
grammed sample is included. The PRO MATE II device
programmer, or the PICSTART Plus development pro-
grammer, can be used to reprogram the device for user
tailored application development. The PICDEM 17
demonstration board supports program download and
execution from external on-board Flash memory. A
generous prototype area is available for user hardware
expansion.
24.16 PICDEM 2 Plus
Demonstration Board
The PICDEM 2 Plus demonstration board supports
many 18-, 28-, and 40-pin microcontrollers, including
PIC16F87X and PIC18FXX2 devices. All the neces-
sary hardware and software is included to run the dem-
onstration programs. The sample microcontrollers
provided with the PICDEM 2 demonstration board can
be programmed with a PRO MATE II device program-
mer, PICSTART Plus development programmer, or
MPLAB ICD 2 with a Universal Programmer Adapter.
The MPLAB ICD 2 and MPLAB ICE in-circuit emulators
may also be used with the PICDEM 2 demonstration
board to test firmware. A prototype area extends the
circuitry for additional application components. Some
of the features include an RS-232 interface, a 2 x 16
LCD display, a piezo speaker, an on-board temperature
sensor, four LEDs, and sample PIC18F452 and
PIC16F877 Flash microcontrollers.
DS39616B-page 334
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
24.20 PICDEM 18R PIC18C601/801
Demonstration Board
24.23 PICDEM USB PIC16C7X5
Demonstration Board
The PICDEM 18R demonstration board serves to assist
development of the PIC18C601/801 family of Microchip
microcontrollers. It provides hardware implementation
of both 8-bit Multiplexed/De-multiplexed and 16-bit
Memory modes. The board includes 2 Mb external
Flash memory and 128 Kb SRAM memory, as well as
serial EEPROM, allowing access to the wide range of
memory types supported by the PIC18C601/801.
The PICDEM USB Demonstration Board shows off the
capabilities of the PIC16C745 and PIC16C765 USB
microcontrollers. This board provides the basis for
future USB products.
24.24 Evaluation and
Programming Tools
In addition to the PICDEM series of circuits, Microchip
has a line of evaluation kits and demonstration software
for these products.
24.21 PICDEM LIN PIC16C43X
Demonstration Board
• KEELOQ evaluation and programming tools for
Microchip’s HCS Secure Data Products
The powerful LIN hardware and software kit includes a
series of boards and three PICmicro microcontrollers.
The small footprint PIC16C432 and PIC16C433 are
used as slaves in the LIN communication and feature
on-board LIN transceivers. A PIC16F874 Flash micro-
controller serves as the master. All three microcontrol-
lers are programmed with firmware to provide LIN bus
communication.
• CAN developers kit for automotive network
applications
• Analog design boards and filter design software
• PowerSmart battery charging evaluation/
calibration kits
• IrDA® development kit
• microID development and rfLabTM development
software
• SEEVAL® designer kit for memory evaluation and
endurance calculations
24.22 PICkitTM 1 Flash Starter Kit
A complete "development system in a box", the PICkit
Flash Starter Kit includes a convenient multi-section
board for programming, evaluation, and development
of 8/14-pin Flash PIC® microcontrollers. Powered via
USB, the board operates under a simple Windows GUI.
The PICkit 1 Starter Kit includes the user's guide (on
CD ROM), PICkit 1 tutorial software and code for vari-
ous applications. Also included are MPLAB® IDE (Inte-
grated Development Environment) software, software
and hardware "Tips 'n Tricks for 8-pin Flash PIC®
Microcontrollers" Handbook and a USB Interface
Cable. Supports all current 8/14-pin Flash PIC
microcontrollers, as well as many future planned
devices.
• PICDEM MSC demo boards for Switching mode
power supply, high power IR driver, delta sigma
ADC, and flow rate sensor
Check the Microchip web page and the latest Product
Line Card for the complete list of demonstration and
evaluation kits.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page335
PIC18F2331/2431/4331/4431
NOTES:
DS39616B-page 336
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
25.0 ELECTRICAL CHARACTERISTICS
(†)
Absolute Maximum Ratings
Ambient temperature under bias.............................................................................................................-55°C to +125°C
Storage temperature .............................................................................................................................. -65°C to +150°C
Voltage on any pin with respect to VSS (except VDD, MCLR, and RA4) ......................................... -0.3V to (VDD + 0.3V)
Voltage on VDD with respect to VSS ......................................................................................................... -0.3V to +7.5V
Voltage on MCLR with respect to VSS (Note 2) ......................................................................................... 0V to +13.25V
Voltage on RA4 with respect to Vss............................................................................................................... 0V to +8.5V
Total power dissipation (Note 1) ...............................................................................................................................1.0W
Maximum current out of VSS pin ...........................................................................................................................300 mA
Maximum current into VDD pin ..............................................................................................................................250 mA
Input clamp current, IIK (VI < 0 or VI > VDD)...................................................................................................................... 20 mA
Output clamp current, IOK (VO < 0 or VO > VDD) .............................................................................................................. 20 mA
Maximum output current sunk by any I/O pin..........................................................................................................25 mA
Maximum output current sourced by any I/O pin ....................................................................................................25 mA
Maximum current sunk by all ports .......................................................................................................................200 mA
Maximum current sourced by all ports ..................................................................................................................200 mA
Note 1: Power dissipation is calculated as follows:
Pdis = VDD x {IDD - ∑ IOH} + ∑ {(VDD-VOH) x IOH} + ∑(VOl x IOL)
2: Voltage spikes below VSS at the MCLR/VPP pin, inducing currents greater than 80 mA, may cause latch-up.
Thus, a series resistor of 50-100Ω should be used when applying a “low” level to the MCLR/VPP pin, rather
than pulling this pin directly to VSS.
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above those
indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 337
PIC18F2331/2431/4331/4431
FIGURE 25-1:
PIC18F2331/2431/4331/4431 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V
5.5V
5.0V
4.5V
4.0V
PIC18F2X31/4X31
4.2V
3.5V
3.0V
2.5V
2.0V
40 MHz
Frequency
FIGURE 25-2:
PIC18LF2331/2431/4331/4431 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V
5.5V
5.0V
4.5V
4.0V
PIC18LF2X31/4X31
4.2V
3.5V
3.0V
2.5V
2.0V
40 MHz
4 MHz
Frequency
FMAX = (16.36 MHz/V) (VDDAPPMIN – 2.0V) + 4 MHz
Note: VDDAPPMIN is the minimum voltage of the PICmicro® device in the application.
DS39616B-page 338
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
25.1 DC Characteristics: Supply Voltage
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
No.
Symbol
Characteristic
Supply Voltage
Min
Typ
Max Units
Conditions
VDD
D001
PIC18LF2X31/4X31 2.0
PIC18F2X31/4X31 4.2
—
—
—
5.5
5.5
—
V
V
V
HS, XT, RC and LP Osc mode
D002
D003
VDR
RAM Data Retention
Voltage
1.5
(1)
VPOR
VDD Start Voltage
to ensure internal Power-
on Reset signal
—
—
—
0.7
—
V
See section on Power-on Reset for details
D004
SVDD
VBOR
VDD Rise Rate
0.05
V/ms See section on Power-on Reset for details
to ensure internal Power-
on Reset signal
Brown-out Reset Voltage
BORV1:BORV0 = 10
BORV1:BORV0 = 01
BORV1:BORV0 = 00
D005
2.45
3.80
4.09
—
—
—
2.99
4.64
4.99
V
V
V
Legend:
Shading of rows is to assist in readability of the table.
Note 1: This is the limit to which VDD can be lowered in Sleep mode, or during a device Reset, without losing RAM data.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 339
PIC18F2331/2431/4331/4431
25.2 DC Characteristics: Power-Down and Supply Current
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
Device
No.
Typ
Max Units
Conditions
(1)
Power-down Current (IPD)
PIC18LF2X31/4X31 0.1
0.5
0.5
1.9
0.5
0.5
1.9
2.0
2.0
6.5
µA
µA
µA
µA
µA
µA
µA
µA
µA
-40°C
25°C
VDD = 2.0V,
(Sleep mode)
0.1
0.2
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
PIC18LF2X31/4X31 0.1
VDD = 3.0V,
(Sleep mode)
0.1
0.3
All devices 0.1
VDD = 5.0V,
(Sleep mode)
0.1
0.4
Legend:
Shading of rows is to assist in readability of the table.
Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta
current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading
and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on
the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.
4: Standard low cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS39616B-page 340
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
25.2 DC Characteristics: Power-Down and Supply Current
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial) (Continued)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
Device
No.
Typ
Max Units
Conditions
(2,3)
Supply Current (IDD)
PIC18LF2X31/4X31
PIC18LF2X31/4X31
All devices
8
40
40
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
9
VDD = 2.0V
11
25
25
20
55
55
50
40
68
FOSC = 31 kHz
(RC_RUN mode,
Internal oscillator source)
68
VDD = 3.0V
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
68
180
180
180
220
220
220
330
330
330
550
550
550
PIC18LF2X31/4X31 140
145
155
PIC18LF2X31/4X31 215
FOSC = 1 MHz
(RC_RUN mode,
Internal oscillator source)
225
235
All devices 385
390
405
Legend:
Shading of rows is to assist in readability of the table.
Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta
current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading
and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on
the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.
4: Standard low cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 341
PIC18F2331/2431/4331/4431
25.2 DC Characteristics: Power-Down and Supply Current
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial) (Continued)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
Device
No.
Typ
Max Units
Conditions
PIC18LF2X31/4X31 410
600
600
600
900
900
900
1.8
µA
µA
µA
µA
µA
µA
mA
mA
mA
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
425
VDD = 2.0V
435
PIC18LF2X31/4X31 650
FOSC = 4 MHz
670
VDD = 3.0V
VDD = 5.0V
(RC_RUN mode,
Internal oscillator source)
680
All devices 1.2
1.2
1.2
1.8
1.8
Legend:
Shading of rows is to assist in readability of the table.
Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta
current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading
and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on
the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.
4: Standard low cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS39616B-page 342
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
25.2 DC Characteristics: Power-Down and Supply Current
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial) (Continued)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
Device
No.
Typ
Max Units
Conditions
(2,3)
Supply Current (IDD)
PIC18LF2X31/4X31 4.7
8
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
5.0
8
VDD = 2.0V
5.8
11
PIC18LF2X31/4X31 7.0
11
FOSC = 31 kHz
7.8
8.7
11
VDD = 3.0V
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
(RC_IDLE mode,
Internal oscillator source)
15
All devices
12
14
14
75
85
95
16
16
22
PIC18LF2X31/4X31
150
150
150
180
180
180
300
300
300
PIC18LF2X31/4X31 110
FOSC = 1 MHz
(RC_IDLE mode,
Internal oscillator source)
125
135
All devices 180
195
200
Legend:
Shading of rows is to assist in readability of the table.
Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta
current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading
and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on
the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.
4: Standard low cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 343
PIC18F2331/2431/4331/4431
25.2 DC Characteristics: Power-Down and Supply Current
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial) (Continued)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
Device
No.
Typ
Max Units
Conditions
PIC18LF2X31/4X31 175
275
275
275
375
375
375
800
800
800
µA
µA
µA
µA
µA
µA
µA
µA
µA
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
185
VDD = 2.0V
195
PIC18LF2X31/4X31 265
FOSC = 4 MHz
280
VDD = 3.0V
VDD = 5.0V
(RC_IDLE mode,
Internal oscillator source)
300
All devices 475
500
505
Legend:
Shading of rows is to assist in readability of the table.
Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta
current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading
and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on
the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.
4: Standard low cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS39616B-page 344
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
25.2 DC Characteristics: Power-Down and Supply Current
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial) (Continued)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
Device
No.
Typ
Max Units
Conditions
(2,3)
Supply Current (IDD)
PIC18LF2X31/4X31 150
250
250
250
350
350
350
1.0
1.0
1.0
600
600
600
1.0
1.0
1.0
2.0
2.0
2.0
12
µA
µA
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
150
VDD = 2.0V
160
µA
PIC18LF2X31/4X31 340
µA
FOSC = 1 MHZ
300
µA
VDD = 3.0V
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
VDD = 4.2V
VDD = 5.0V
(PRI_RUN,
EC oscillator)
280
µA
All devices 0.72
mA
mA
mA
µA
0.63
0.57
PIC18LF2X31/4X31 440
450
µA
460
µA
PIC18LF2X31/4X31 0.80
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
FOSC = 4 MHz
(PRI_RUN,
EC oscillator)
0.78
0.77
All devices 1.6
1.5
1.5
All devices 9.5
9.7
12
FOSC = 40 MHZ
(PRI_RUN,
EC oscillator)
9.9
All devices 11.9
12.1
12
15
15
12.3
15
Legend:
Shading of rows is to assist in readability of the table.
Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta
current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading
and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on
the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.
4: Standard low cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 345
PIC18F2331/2431/4331/4431
25.2 DC Characteristics: Power-Down and Supply Current
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial) (Continued)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
Device
No.
Typ
Max Units
Conditions
(2,3)
Supply Current (IDD)
PIC18LF2X31/4X31
35
35
35
55
50
60
50
50
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
mA
mA
mA
mA
mA
mA
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
-40°C
25°C
85°C
VDD = 2.0V
60
PIC18LF2X31/4X31
80
FOSC = 1 MHz
80
VDD = 3.0V
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
VDD = 4.2 V
(PRI_IDLE mode,
EC oscillator)
100
150
150
150
180
180
180
280
280
280
525
525
525
4.1
4.1
4.1
5.1
5.1
5.1
All devices 105
110
115
PIC18LF2X31/4X31 135
140
140
PIC18LF2X31/4X31 215
FOSC = 4 MHz
(PRI_IDLE mode,
EC oscillator)
225
230
All devices 410
420
430
All devices 3.2
3.2
FOSC = 40 MHz
(PRI_IDLE mode,
EC oscillator)
3.3
All devices 4.0
4.1
4.1
VDD = 5.0V
Legend:
Shading of rows is to assist in readability of the table.
Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta
current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading
and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on
the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.
4: Standard low cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS39616B-page 346
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
25.2 DC Characteristics: Power-Down and Supply Current
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial) (Continued)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
Device
No.
Typ
Max Units
Conditions
(2,3)
Supply Current (IDD)
PIC18LF2X31/4X31 5.1
9
µA
µA
µA
µA
µA
µA
µA
µA
µA
-10°C
25°C
70°C
-10°C
25°C
70°C
-10°C
25°C
70°C
5.8
9
VDD = 2.0V
7.9
11
12
12
14
20
20
25
PIC18LF2X31/4X31 7.9
(4)
FOSC = 32 kHz
8.9
10.5
VDD = 3.0V
VDD = 5.0V
(SEC_RUN mode,
Timer1 as clock)
All devices 12.5
16.3
18.9
(2,3)
Supply Current (IDD)
PIC18LF2X31/4X31 9.2
15
15
18
30
30
35
80
80
85
µA
µA
µA
µA
µA
µA
µA
µA
µA
-10°C
25°C
70°C
-10°C
25°C
70°C
-10°C
25°C
70°C
9.6
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
12.7
PIC18LF2X31/4X31 22.0
(4)
FOSC = 32 kHz
21.0
20.0
(SEC_IDLE mode,
Timer1 as clock)
All devices
30
45
45
Legend:
Shading of rows is to assist in readability of the table.
Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta
current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading
and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on
the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.
4: Standard low cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 347
PIC18F2331/2431/4331/4431
25.2 DC Characteristics: Power-Down and Supply Current
PIC18F2331/2431/4331/4431 (Industrial, Extended)
PIC18LF2331/2431/4331/4431 (Industrial) (Continued)
PIC18F2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial, Extended)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18LF2331/2431/4331/4431
Standard Operating Conditions (unless otherwise stated)
(Industrial)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Param
Device
No.
Typ
Max Units
Conditions
Module Differential Currents (∆IWDT, ∆IBOR, ∆ILVD, ∆IOSCB, ∆IAD)
D022
(∆IWDT)
Watchdog Timer 1.5
4.0
4.0
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
-40°C
25°C
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
2.2
3.1
2.5
3.3
4.7
3.7
4.5
6.1
5.0
85°C
6.0
-40°C
6.0
25°C
7.0
85°C
10.0
10.0
13.0
35.0
45.0
25.0
35.0
45.0
3.5
-40°C
25°C
85°C
VDD = 3.0V
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
D022A
(∆IBOR)
D022B
(∆ILVD)
Brown-out Reset
19
24
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C
Low-Voltage Detect 8.5
16
20
D025
Timer1 Oscillator 1.7
(4)
(4)
(4)
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
32 kHz on Timer1
32 kHz on Timer1
32 kHz on Timer1
(∆IOSCB)
1.8
3.5
25°C
2.1
4.5
85°C
2.2
4.5
-40°C
2.6
4.5
25°C
2.8
5.5
85°C
3.0
6.0
-40°C
3.3
6.0
25°C
3.6
7.0
85°C
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
D026
(∆IAD)
A/D Converter 1.0
3.0
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
A/D on, not converting
1.0
2.0
4.0
10.0
Legend:
Shading of rows is to assist in readability of the table.
Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta
current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading
and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on
the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.
4: Standard low cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS39616B-page 348
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
25.3 DC Characteristics: PIC18F2331/2431/4331/4431 (Industrial)
PIC18LF2331/2431/4331/4431 (Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
DC CHARACTERISTICS
Param
Symbol
No.
Characteristic
Min
Max
Units
Conditions
VIL
VIH
IIL
Input Low Voltage
I/O ports:
with TTL buffer
D030
D030A
D031
VSS
—
0.15 VDD
0.8
V
V
VDD < 4.5V
4.5V ≤ VDD ≤ 5.5V
with Schmitt Trigger buffer
RC3 and RC4
VSS
VSS
0.2 VDD
0.3 VDD
V
V
D032
MCLR
VSS
VSS
0.2 VDD
0.3 VDD
V
V
D032A
OSC1 and T1OSI
LP, XT, HS, HSPLL
modes(1)
EC mode(1)
D033
OSC1
VSS
0.2 VDD
V
Input High Voltage
I/O ports:
D040
D040A
D041
with TTL buffer
0.25 VDD + 0.8V
2.0
VDD
VDD
V
V
VDD < 4.5V
4.5V ≤ VDD ≤ 5.5V
with Schmitt Trigger buffer
RC3 and RC4
0.8 VDD
0.7 VDD
VDD
VDD
V
V
D042
MCLR
0.8 VDD
0.7 VDD
VDD
VDD
V
V
D042A
OSC1 and T1OSI
LP, XT, HS, HSPLL
modes(1)
EC mode(1)
D043
D060
OSC1
0.8 VDD
—
VDD
1
V
Input Leakage Current(2,3)
I/O ports
µA VSS ≤ VPIN ≤ VDD,
Pin at hi-impedance
D061
D063
MCLR
—
—
1
1
µA Vss ≤ VPIN ≤ VDD
µA Vss ≤ VPIN ≤ VDD
OSC1
IPU
Weak Pull-up Current
PORTB weak pull-up current
D070
IPURB
50
400
µA VDD = 5V, VPIN = VSS
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PICmicro device be driven with an external clock while in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified
levels represent normal operating conditions. Higher leakage current may be measured at different input
voltages.
3: Negative current is defined as current sourced by the pin.
4: Parameter is characterized but not tested.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 349
PIC18F2331/2431/4331/4431
25.3 DC Characteristics: PIC18F2331/2431/4331/4431 (Industrial)
PIC18LF2331/2431/4331/4431 (Industrial) (Continued)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
DC CHARACTERISTICS
Param
Symbol
No.
Characteristic
Min
Max
Units
Conditions
VOL
VOH
VOD
Output Low Voltage
I/O ports
D080
D083
—
—
0.6
0.6
V
V
IOL = 8.5 mA, VDD = 4.5V,
-40°C to +85°C
OSC2/CLKO
(RC, RCIO, EC, ECIO modes)
Output High Voltage(3)
IOL = 1.6 mA, VDD = 4.5V,
-40°C to +85°C
D090
D092
D150
I/O ports
VDD – 0.7
VDD – 0.7
—
—
—
V
V
V
IOH = -3.0 mA, VDD = 4.5V,
-40°C to +85°C
OSC2/CLKO
(RC, RCIO, EC, ECIO modes)
IOH = -1.3 mA, VDD = 4.5V,
-40°C to +85°C
RA4 pin
Open-Drain High Voltage
8.5
Capacitive Loading Specs
on Output Pins
D100(4)
—
COSC2 OSC2 pin
15
pF In XT, HS and LP modes
when external clock is
used to drive OSC1
D101
D102
CIO
CB
All I/O pins and OSC2
(in RC mode)
—
—
50
pF To meet the AC Timing
Specifications
pF I2C™ Specification
SCL, SDA
400
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PICmicro device be driven with an external clock while in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified
levels represent normal operating conditions. Higher leakage current may be measured at different input
voltages.
3: Negative current is defined as current sourced by the pin.
4: Parameter is characterized but not tested.
DS39616B-page 350
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
TABLE 25-1: MEMORY PROGRAMMING REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
DC Characteristics
Param
Sym
No.
Characteristic
Min
Typ†
Max
Units
Conditions
Internal Program Memory
Programming Specifications(1)
VPP
IPP
9.00
—
—
—
—
13.25
300
1
V
(Note 3)
D110
D112
D113
Voltage on MCLR/VPP pin
Current into MCLR/VPP pin
µA
mA
IDDP
—
Supply Current during
Programming
Data EEPROM Memory
—
D120
ED
Byte Endurance
100K
VMIN
1M
—
E/W -40°C to +85°C
D121 VDRW VDD for Read/Write
5.5
V
Using EECON to read/write
VMIN = Minimum operating
voltage
—
—
—
D122 TDEW Erase/Write Cycle Time
D123 TRETD Characteristic Retention
4
ms
40
—
Year Provided no other
specifications are violated
—
D124
TREF
Number of Total Erase/Write
Cycles before Refresh(2)
1M
10M
E/W -40°C to +85°C
Program Flash Memory
Cell Endurance
—
D130
D131
EP
10K
100K
—
E/W -40°C to +85°C
VPR
VDD for Read
VMIN
5.5
V
VMIN = Minimum operating
voltage
—
—
D132
VIE
VDD for Block Erase
4.5
4.5
5.5
5.5
V
V
Using ICSP port
Using ICSP port
D132A VIW
VDD for Externally Timed Erase
or Write
—
D132B VPEW VDD for Self-timed Write
VMIN
5.5
V
VMIN = Minimum operating
voltage
D133
TIE
ICSP Block Erase Cycle Time
—
1
4
—
—
ms VDD > 4.5V
ms VDD > 4.5V
D133A TIW
ICSP Erase or Write Cycle Time
(externally timed)
—
D133A TIW
Self-timed Write Cycle Time
—
2
—
—
ms
D134 TRETD Characteristic Retention
40
100
Year Provided no other
specifications are violated
†
Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: These specifications are for programming the on-chip program memory through the use of Table Write
instructions.
2: Refer to Section 7.8 “Using the Data EEPROM” for a more detailed discussion on data EEPROM
endurance.
3: Required only if low-voltage programming is disabled.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 351
PIC18F2331/2431/4331/4431
FIGURE 25-3:
LOW-VOLTAGE DETECT CHARACTERISTICS
VDD
(LVDIF can be
cleared in software)
VLVD
(LVDIF set by hardware)
LVDIF
TABLE 25-2: LOW-VOLTAGE DETECT CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
Param
No.
Symbol
Characteristic
Min
Typ† Max
Units
Conditions
D420
LVV = 0010 2.08
LVV = 0011 2.26
LVV = 0100 2.35
LVV = 0101 2.55
LVV = 0110 2.64
LVV = 0111 2.82
LVV = 1000 3.09
LVV = 1001 3.29
LVV = 1010 3.38
LVV = 1011 3.56
LVV = 1100 3.75
LVV = 1101 3.93
LVV = 1110 4.23
2.26
2.45
2.55
2.77
2.87
3.07
3.36
3.57
3.67
3.87
4.07
4.28
4.60
2.44
2.65
2.76
2.99
3.10
3.31
3.63
3.86
3.96
4.18
4.40
4.62
4.96
V
V
V
V
V
V
V
V
V
V
V
V
V
LVD Voltage on VDD
Transition High to Low
†
Production tested at TAMB = 25°C. Specifications over temp. limits ensured by characterization.
DS39616B-page 352
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
25.4 AC (Timing) Characteristics
25.4.1 TIMING PARAMETER SYMBOLOGY
The timing parameter symbols have been created
following one of the following formats:
1. TppS2ppS
2. TppS
T
3. TCC:ST
4. Ts
(I2C specifications only)
(I2C specifications only)
F
Frequency
T
Time
Lowercase letters (pp) and their meanings:
pp
cc
ck
cs
di
CCP1
CLKO
CS
osc
rd
OSC1
RD
rw
sc
ss
t0
RD or WR
SCK
SDI
do
dt
SDO
SS
Data in
I/O port
MCLR
T0CKI
T1CKI
WR
io
t1
mc
wr
Uppercase letters and their meanings:
S
F
Fall
P
R
V
Z
Period
H
High
Rise
I
Invalid (Hi-impedance)
Low
Valid
L
Hi-impedance
I2C only
AA
output access
Bus free
High
Low
High
Low
BUF
TCC:ST (I2C specifications only)
CC
HD
Hold
SU
Setup
ST
DAT
STA
DATA input hold
Start condition
STO
Stop condition
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 353
PIC18F2331/2431/4331/4431
25.4.2
TIMING CONDITIONS
Note: Because of space limitations, the generic
terms “PIC18FXX31” and “PIC18LFXX31”
are used throughout this section to refer to
the PIC18F2331/2431/4331/4431 and
PIC18LF2331/2431/4331/4431 families of
devices specifically, and only those
devices.
The temperature and voltages specified in Table 25-3
apply to all timing specifications unless otherwise
noted. Figure 25-4 specifies the load conditions for the
timing specifications.
TABLE 25-3: TEMPERATURE AND VOLTAGE SPECIFICATIONS - AC
Standard Operating Conditions (unless otherwise stated)
Operating temperature
Operating voltage VDD range as described in DC spec Section 25.1 and
Section 25.3. LF parts operate for industrial temperatures only.
-40°C ≤ TA ≤ +85°C for industrial
AC CHARACTERISTICS
FIGURE 25-4:
LOAD CONDITIONS FOR DEVICE TIMING SPECIFICATIONS
Load Condition 1 Load Condition 2
VDD/2
CL
RL
Pin
VSS
CL
Pin
RL = 464Ω
CL = 50 pF for all pins except OSC2/CLKO
and including D and E outputs as ports
VSS
DS39616B-page 354
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
25.4.3
TIMING DIAGRAMS AND SPECIFICATIONS
FIGURE 25-5:
EXTERNAL CLOCK TIMING (ALL MODES EXCEPT PLL)
Q4
Q1
1
Q2
Q3
Q4
Q1
OSC1
CLKO
3
4
3
4
2
TABLE 25-4: EXTERNAL CLOCK TIMING REQUIREMENTS
Param.
Symbol
Characteristic
Min
Max
Units
Conditions
No.
1A
FOSC
External CLKI Frequency(1)
Oscillator Frequency(1)
DC
DC
0.1
4
40
4
MHz EC, ECIO
MHz RC osc
MHz XT osc
MHz HS osc
4
25
10
200
4
MHz HS + PLL osc
kHz LP Osc mode
5
1
TOSC
External CLKI Period(1)
Oscillator Period(1)
25
—
ns
EC, ECIO
250
250
—
ns
ns
RC osc
XT osc
10,000
25
100
250
250
ns
ns
HS osc
HS + PLL osc
25
—
µs
LP osc
2
3
TCY
Instruction Cycle Time(1)
100
30
2.5
10
—
—
—
ns
ns
µs
ns
ns
ns
ns
TCY = 4/FOSC
XT osc
TosL,
TosH
External Clock in (OSC1)
High or Low Time
—
LP osc
—
HS osc
XT osc
4
TosR,
TosF
External Clock in (OSC1)
Rise or Fall Time
20
50
7.5
—
LP osc
—
HS osc
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period for all configurations
except PLL. All specified values are based on characterization data for that particular oscillator type under
standard operating conditions with the device executing code. Exceeding these specified limits may result
in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested
to operate at “min.” values with an external clock applied to the OSC1/CLKI pin. When an external clock
input is used, the “max.” cycle time limit is “DC” (no clock) for all devices.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 355
PIC18F2331/2431/4331/4431
TABLE 25-5: PLL CLOCK TIMING SPECIFICATIONS (VDD = 4.2V TO 5.5V)
Param
Sym
Characteristic
Min
Typ†
Max
Units Conditions
No.
F10
FOSC Oscillator Frequency Range
FSYS On-chip VCO System Frequency
TPLL PLL Start-up Time (Lock Time)
∆CLK CLKO Stability (Jitter)
4
—
—
—
—
10
40
2
MHz HS mode only
F11
F12
F13
16
—
-2
MHz HS mode only
ms
+2
%
†
Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only
and are not tested.
TABLE 25-6: INTERNAL RC ACCURACY
PIC18F2331/2431/4331/4431 (Industrial)
PIC18LF2331/2431/4331/4431 (Industrial)
PIC18F1220/1320
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
(Industrial)
PIC18LF1220/1320
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
(Industrial)
Param
No.
Device
Min
Typ
Max
Units
Conditions
(1)
INTOSC Accuracy @ Freq = 8 MHz, 4 MHz, 2 MHz, 1 MHz, 500 kHz, 250 kHz, 125 kHz
F2
F3
PIC18LF2331/2431/4331/4431
All devices
-15
+/-5
+/-5
+15
+15
%
%
25°C
25°C
VDD = 3.0V
VDD = 5.0V
-15
(2)
INTRC Accuracy @ Freq = 31 kHz
F5
F6
PIC18LF2331/2431/4331/4431 26.562
All devices 26.562
—
—
35.938
35.938
kHz
kHz
25°C
25°C
VDD = 3.0V
VDD = 5.0V
(3)
INTRC Stability
F8
PIC18LF2331/2431/4331/4431
All devices
TBD
TBD
1
1
TBD
TBD
%
%
25°C
25°C
VDD = 3.0V
VDD = 5.0V
F9
Legend:
Shading of rows is to assist in readability of the table.
Note 1: Frequency calibrated at 25°C. OSCTUNE register can be used to compensate for temperature drift.
2: INTRC frequency after calibration.
3: Change of INTRC frequency as VDD changes.
DS39616B-page 356
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 25-6:
CLKO AND I/O TIMING
Q1
Q2
Q3
Q4
OSC1
11
10
CLKO
13
12
19
18
14
16
I/O Pin
(Input)
15
17
I/O Pin
(Output)
New Value
Old Value
20, 21
Refer to Figure 25-4 for load conditions.
Note:
TABLE 25-7: CLKO AND I/O TIMING REQUIREMENTS
Param
Symbol
Characteristic
Min
Typ
Max
Units Conditions
No.
10
TosH2ckL OSC1 ↑ to CLKO ↓
TosH2ckH OSC1 ↑ to CLKO ↑
—
—
—
—
—
75
75
35
35
—
—
—
50
—
—
200
200
100
100
ns
ns
ns
ns
(1)
(1)
(1)
(1)
(1)
(1)
(1)
11
12
13
14
15
16
17
18
18A
TckR
TckF
CLKO rise time
CLKO fall time
TckL2ioV CLKO ↓ to Port out valid
TioV2ckH Port in valid before CLKO ↑
TckH2ioI Port in hold after CLKO ↑
TosH2ioV OSC1↑ (Q1 cycle) to Port out valid
0.5 TCY + 20 ns
0.25 TCY + 25
—
—
ns
ns
ns
ns
ns
0
—
150
—
TosH2ioI OSC1↑ (Q2 cycle) to
Port input invalid
PIC18FXX31
PIC18LFXX31
100
200
—
(I/O in hold time)
19
TioV2osH Port input valid to OSC1↑ (I/O in setup time)
0
—
—
10
—
10
—
—
—
—
25
60
25
60
—
—
ns
ns
ns
ns
ns
ns
ns
ns
20
TioR
Port output rise time
Port output fall time
INT pin high or low time
PIC18FXX31
PIC18LFXX31
PIC18FXX31
PIC18LFXX31
20A
21
—
TioF
—
21A
22††
23††
24††
—
TINP
TCY
TCY
20
TRBP
TRCP
RB7:RB4 change INT high or low time
RB7:RB4 change INT high or low time
†† These parameters are asynchronous events not related to any internal clock edges.
Note 1: Measurements are taken in RC mode, where CLKO output is 4 x TOSC.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 357
PIC18F2331/2431/4331/4431
FIGURE 25-7:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
VDD
MCLR
30
Internal
POR
33
PWRT
Time-out
32
OSC
Time-out
Internal
Reset
Watchdog
Timer
Reset
31
34
34
I/O Pins
Note:
Refer to Figure 25-4 for load conditions.
FIGURE 25-8:
BROWN-OUT RESET TIMING
BVDD
VDD
35
VBGAP = 1.2V
VIRVST
Enable Internal Reference Voltage
Internal Reference Voltage Stable
36
TABLE 25-8: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET REQUIREMENTS
Param.
No.
Symbol
Characteristic
Min
Typ
Max
Units
Conditions
30
TmcL
TWDT
MCLR Pulse Width (low)
2
—
—
µs
ms
31
Watchdog Timer Time-out Period
(No Postscaler)
—
4.00
TBD
32
33
TOST
Oscillation Start-up Timer Period
1024 TOSC
—
—
1024 TOSC
TBD
—
TOSC = OSC1 period
TPWRT Power-up Timer Period
65.5
ms
34
TIOZ
I/O Hi-impedance from MCLR Low
or Watchdog Timer Reset
—
2
—
µs
35
36
TBOR
Brown-out Reset Pulse Width
200
—
—
—
µs VDD ≤ BVDD (see D005)
µs
TIVRST Time for Internal Reference
Voltage to become stable
20
50
37
TLVD
Low-Voltage Detect Pulse Width
200
—
—
µs
VDD ≤ VLVD
DS39616B-page 358
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 25-9:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI
41
40
42
T1OSO/T1CKI
46
45
47
48
TMR0 or
TMR1
Note:
Refer to Figure 25-4 for load conditions.
TABLE 25-9: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
Symbol
Characteristic
Min
Max Units
Conditions
No.
40
Tt0H
T0CKI High Pulse Width
No Prescaler
With Prescaler
No Prescaler
With Prescaler
No Prescaler
With Prescaler
0.5 TCY + 20
10
—
—
—
—
—
—
ns
ns
ns
ns
ns
41
42
Tt0L
Tt0P
T0CKI Low Pulse Width
T0CKI Period
0.5 TCY + 20
10
TCY + 10
Greater of:
20 ns or TCY + 40
N
ns N = prescale
value
(1, 2, 4,..., 256)
45
46
Tt1H
Tt1L
T1CKI
High Time
Synchronous, no prescaler
0.5 TCY + 20
—
—
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Synchronous,
with prescaler
PIC18FXX31
PIC18LFXX31
10
25
—
Asynchronous PIC18FXX31
PIC18LFXX31
30
—
50
0.5 TCY + 5
10
—
T1CKI
Low Time
Synchronous, no prescaler
—
Synchronous,
with prescaler
PIC18FXX31
PIC18LFXX31
—
25
—
Asynchronous PIC18FXX31
PIC18LFXX31
30
—
TBD
TBD
—
47
48
Tt1P
Ft1
T1CKI
Input
Period
Synchronous
Greater of:
20 ns or TCY + 40
N
ns N = prescale
value
(1, 2, 4, 8)
Asynchronous
60
DC
—
50
ns
kHz
—
T1CKI Oscillator Input Frequency Range
Tcke2tmrI Delay from External T1CKI Clock Edge to
Timer Increment
2 TOSC
7 TOSC
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 359
PIC18F2331/2431/4331/4431
FIGURE 25-10:
CAPTURE/COMPARE/PWM TIMINGS (ALL CCP MODULES)
CCPx
(Capture Mode)
50
51
52
54
CCPx
(Compare or PWM Mode)
53
Refer to Figure 25-4 for load conditions.
Note:
TABLE 25-10: CAPTURE/COMPARE/PWM REQUIREMENTS (ALL CCP MODULES)
Param
Symbol
Characteristic
Min
Max
Units
Conditions
No.
50
TccL
CCPx input low No Prescaler
0.5 TCY + 20
—
—
—
—
—
—
—
ns
ns
ns
ns
ns
ns
ns
time
With
Prescaler
PIC18FXX31
PIC18LFXX31
10
20
51
TccH
CCPx input high No Prescaler
0.5 TCY + 20
time
With
Prescaler
PIC18FXX31
PIC18LFXX31
10
20
52
53
TccP
TccR
CCPx input period
3 TCY + 40
N
N = prescale
value (1,4 or 16)
CCPx output fall time
PIC18FXX31
PIC18LFXX31
PIC18FXX31
PIC18LFXX31
—
—
—
—
25
45
25
45
ns
ns
ns
ns
54
TccF
CCPx output fall time
DS39616B-page 360
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 25-11:
EXAMPLE SPI MASTER MODE TIMING (CKE = 0)
SS
70
SCK
(CKP = 0)
71
72
78
79
79
SCK
(CKP = 1)
78
80
MSb
bit6 - - - - - -1
bit6 - - - -1
LSb
SDO
SDI
75, 76
MSb IN
74
LSb IN
73
Note: Refer to Figure 25-4 for load conditions.
TABLE 25-11: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 0)
Param
Symbol
Characteristic
Min
Max Units Conditions
No.
70
TssL2scH, SS↓ to SCK↓ or SCK↑ input
TssL2scL
TCY
—
ns
71
TscH
SCK input high time
(Slave mode)
Continuous
Single Byte
Continuous
Single Byte
1.25 TCY + 30
—
—
—
—
ns
71A
72
40
1.25 TCY + 30
40
ns (Note 1)
ns
TscL
SCK input low time
(Slave mode)
72A
73
ns (Note 1)
TdiV2scH, Setup time of SDI data input to SCK edge
TdiV2scL
100
1.5 TCY + 40
100
—
—
—
ns
73A
74
TB2B
Last clock edge of Byte1 to the 1st clock edge
of Byte2
(Note 2)
ns
TscH2diL, Hold time of SDI data input to SCK edge
TscL2diL
ns
75
TdoR
SDO data output rise time
PIC18FXX31
PIC18LFXX31
—
—
—
—
—
—
—
—
25
45
25
25
45
25
50
100
ns
ns
ns
ns
ns
ns
ns
ns
76
78
TdoF
TscR
SDO data output fall time
SCK output rise time
(Master mode)
PIC18FXX31
PIC18LFXX31
79
80
TscF
SCK output fall time (Master mode)
TscH2doV, SDO data output valid after
TscL2doV SCK edge
PIC18FXX31
PIC18LFXX31
Note 1: Requires the use of Parameter # 73A.
2: Only if Parameter # 71A and # 72A are used.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 361
PIC18F2331/2431/4331/4431
FIGURE 25-12:
EXAMPLE SPI MASTER MODE TIMING (CKE = 1)
SS
81
SCK
(CKP = 0)
71
72
79
78
73
SCK
(CKP = 1)
80
LSb
MSb
bit6 - - - - - -1
bit6 - - - -1
SDO
SDI
75, 76
MSb IN
74
LSb IN
Note: Refer to Figure 25-4 for load conditions.
TABLE 25-12: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 1)
Param.
Symbol
TscH
TscL
Characteristic
Min
Max Units Conditions
No.
71
SCK input high time
Continuous
Single Byte
Continuous
Single Byte
1.25 TCY + 30
—
—
—
—
ns
(Slave mode)
71A
72
40
1.25 TCY + 30
40
ns (Note 1)
ns
SCK input low time
(Slave mode)
72A
73
ns (Note 1)
TdiV2scH, Setup time of SDI data input to SCK edge
TdiV2scL
100
—
—
—
ns
73A
74
TB2B
Last clock edge of Byte1 to the 1st clock edge
of Byte2
1.5 TCY + 40
ns (Note 2)
TscH2diL, Hold time of SDI data input to SCK edge
TscL2diL
100
—
ns
75
TdoR
SDO data output rise time
PIC18FXX31
PIC18LFXX31
25
45
25
25
45
25
50
100
ns
ns
ns
ns
ns
ns
ns
ns
76
78
TdoF
TscR
SDO data output fall time
—
—
SCK output rise time
(Master mode)
PIC18FXX31
PIC18LFXX31
79
80
TscF
SCK output fall time (Master mode)
—
—
TscH2doV, SDO data output valid after
TscL2doV SCK edge
PIC18FXX31
PIC18LFXX31
81
TdoV2scH, SDO data output setup to SCK edge
TdoV2scL
TCY
—
ns
Note 1: Requires the use of Parameter # 73A.
2: Only if Parameter # 71A and # 72A are used.
DS39616B-page 362
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 25-13:
EXAMPLE SPI SLAVE MODE TIMING (CKE = 0)
SS
70
SCK
(CKP = 0)
83
71
72
78
79
79
SCK
(CKP = 1)
78
80
MSb
LSb
SDO
SDI
bit6 - - - - - -1
bit6 - - - -1
77
75, 76
MSb IN
74
LSb IN
73
Note:
Refer to Figure 25-4 for load conditions.
TABLE 25-13: EXAMPLE SPI MODE REQUIREMENTS (SLAVE MODE TIMING (CKE = 0))
Param
Symbol
Characteristic
Min
Max Units Conditions
No.
70
TssL2scH, SS↓ to SCK↓ or SCK↑ input
TssL2scL
TCY
—
ns
71
TscH
SCK input high time
(Slave mode)
Continuous
Single Byte
Continuous
Single Byte
1.25 TCY + 30
—
—
—
—
—
ns
71A
72
40
1.25 TCY + 30
40
ns (Note 1)
TscL
SCK input low time
(Slave mode)
ns
72A
73
ns (Note 1)
TdiV2scH, Setup time of SDI data input to SCK edge
TdiV2scL
100
ns
73A
74
TB2B
Last clock edge of Byte1 to the first clock edge of Byte2
1.5 TCY + 40
100
—
—
ns (Note 2)
TscH2diL, Hold time of SDI data input to SCK edge
TscL2diL
ns
75
TdoR
SDO data output rise time
PIC18FXX31
PIC18LFXX31
—
25
45
25
50
25
45
25
50
100
—
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
76
77
78
TdoF
SDO data output fall time
—
10
—
TssH2doZ SS↑ to SDO output hi-impedance
TscR
SCK output rise time (Master mode)
PIC18FXX31
PIC18LFXX31
79
80
TscF
SCK output fall time (Master mode)
—
—
TscH2doV, SDO data output valid after SCK edge PIC18FXX31
TscL2doV
PIC18LFXX31
83
TscH2ssH, SS ↑ after SCK edge
TscL2ssH
1.5 TCY + 40
Note 1: Requires the use of Parameter # 73A.
2: Only if Parameter # 71A and # 72A are used.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 363
PIC18F2331/2431/4331/4431
FIGURE 25-14:
EXAMPLE SPI SLAVE MODE TIMING (CKE = 1)
82
SS
70
SCK
83
(CKP = 0)
71
72
SCK
(CKP = 1)
80
MSb
bit6 - - - - - -1
LSb
SDO
SDI
75, 76
77
MSb IN
74
bit6 - - - -1
LSb IN
Note: Refer to Figure 25-4 for load conditions.
TABLE 25-14: EXAMPLE SPI SLAVE MODE REQUIREMENTS (CKE = 1)
Param
Symbol
Characteristic
Min
Max Units Conditions
No.
70
TssL2scH, SS↓ to SCK↓ or SCK↑ input
TssL2scL
—
ns
TCY
71
TscH
TscL
TB2B
SCK input high time
(Slave mode)
Continuous
Single Byte
Continuous
Single Byte
1.25 TCY + 30
—
—
—
—
—
—
ns
71A
72
40
1.25 TCY + 30
40
ns (Note 1)
ns
SCK input low time
(Slave mode)
72A
73A
74
ns (Note 1)
ns (Note 2)
ns
Last clock edge of Byte1 to the first clock edge of Byte2 1.5 TCY + 40
TscH2diL, Hold time of SDI data input to SCK edge
TscL2diL
100
—
75
TdoR
SDO data output rise time
PIC18FXX31
PIC18LFXX31
25
45
25
50
25
45
25
50
100
50
100
—
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
76
77
78
TdoF
SDO data output fall time
—
10
—
—
—
—
—
—
—
TssH2doZ SS↑ to SDO output hi-impedance
TscR
SCK output rise time
(Master mode)
PIC18FXX31
PIC18LFXX31
79
80
TscF
SCK output fall time (Master mode)
TscH2doV, SDO data output valid after SCK PIC18FXX31
TscL2doV edge
PIC18LFXX31
82
83
TssL2doV SDO data output valid after SS↓ PIC18FXX31
edge
PIC18LFXX31
TscH2ssH, SS ↑ after SCK edge
TscL2ssH
1.5 TCY + 40
Note 1: Requires the use of Parameter # 73A.
2: Only if Parameter # 71A and # 72A are used.
DS39616B-page 364
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 25-15:
I2C BUS START/STOP BITS TIMING
SCL
SDA
91
93
90
92
Stop
Condition
Start
Condition
Note: Refer to Figure 25-4 for load conditions.
TABLE 25-15: I2C BUS START/STOP BITS REQUIREMENTS (SLAVE MODE)
Param.
Symbol
Characteristic
Min
Max
Units
Conditions
No.
90
TSU:STA Start condition
Setup time
100 kHz mode
400 kHz mode
100 kHz mode
400 kHz mode
100 kHz mode
400 kHz mode
100 kHz mode
400 kHz mode
4700
600
—
—
—
—
—
—
—
—
ns
Only relevant for repeated
Start condition
91
92
93
THD:STA Start condition
Hold time
4000
600
ns
ns
ns
After this period, the first
clock pulse is generated
TSU:STO Stop condition
Setup time
4700
600
THD:STO Stop condition
Hold time
4000
600
FIGURE 25-16:
I2C BUS DATA TIMING
103
102
100
101
SCL
90
106
107
91
92
SDA
In
110
109
109
SDA
Out
Note: Refer to Figure 25-4 for load conditions.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 365
PIC18F2331/2431/4331/4431
TABLE 25-16: I2C BUS DATA REQUIREMENTS (SLAVE MODE)
Param.
No.
Symbol
Characteristic
100 kHz mode
Min
Max
Units
Conditions
Clock high time
4.0
—
µs
PIC18FXX31 must operate at
a minimum of 1.5 MHz
100
THIGH
400 kHz mode
0.6
—
µs
PIC18FXX31 must operate at
a minimum of 10 MHz
SSP Module
1.5 TCY
4.7
—
—
Clock low time
100 kHz mode
µs
µs
PIC18FXX31 must operate at
a minimum of 1.5 MHz
101
TLOW
400 kHz mode
1.3
—
PIC18FXX31 must operate at
a minimum of 10 MHz
SSP Module
1.5 TCY
—
—
SDA and SCL rise
time
100 kHz mode
400 kHz mode
1000
300
ns
ns
102
103
TR
TF
20 + 0.1 CB
CB is specified to be from
10 to 400 pF
SDA and SCL fall
time
100 kHz mode
400 kHz mode
—
300
300
ns
ns
20 + 0.1 CB
CB is specified to be from
10 to 400 pF
Start condition setup 100 kHz mode
4.7
0.6
4.0
0.6
0
—
—
µs
µs
µs
µs
ns
µs
ns
ns
µs
µs
ns
ns
µs
µs
Only relevant for repeated
Start condition
90
TSU:STA
THD:STA
THD:DAT
TSU:DAT
TSU:STO
TAA
time
400 kHz mode
Start condition hold
time
100 kHz mode
400 kHz mode
100 kHz mode
400 kHz mode
—
After this period, the first clock
pulse is generated
91
—
Data input hold time
—
106
107
92
0
0.9
—
Data input setup time 100 kHz mode
400 kHz mode
250
100
4.7
0.6
—
(Note 2)
—
Stop condition setup 100 kHz mode
—
time
400 kHz mode
—
Output valid from
clock
100 kHz mode
400 kHz mode
100 kHz mode
400 kHz mode
3500
—
(Note 1)
109
110
—
Bus free time
4.7
1.3
—
Time the bus must be free
before a new transmission can
start
TBUF
—
D102
CB
Bus capacitive loading
—
400
pF
Note 1: As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region
(min. 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
2: A Fast mode I2C bus device can be used in a Standard mode I2C bus system, but the requirement
TSU:DAT ≥ 250 ns must then be met. This will automatically be the case if the device does not stretch the
LOW period of the SCL signal. If such a device does stretch the LOW period of the SCL signal, it must out-
put the next data bit to the SDA line.
TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according to the Standard mode I2C bus specification) before
the SCL line is released.
DS39616B-page 366
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 25-17:
SSP I2C BUS START/STOP BITS TIMING WAVEFORMS
SCL
SDA
93
91
90
92
Stop
Condition
Start
Condition
Note: Refer to Figure 25-4 for load conditions.
TABLE 25-17: SSP I2C BUS START/STOP BITS REQUIREMENTS
Param.
Symbol
Characteristic
Min
Max Units
Conditions
No.
90
TSU:STA Start condition
Setup time
100 kHz mode
400 kHz mode
1 MHz mode(1) 2(TOSC)(BRG + 1)
2(TOSC)(BRG + 1)
2(TOSC)(BRG + 1)
—
—
—
—
—
—
—
—
—
—
—
—
ns Only relevant for
repeated Start
condition
91
92
93
THD:STA Start condition
Hold time
100 kHz mode
400 kHz mode
1 MHz mode(1) 2(TOSC)(BRG + 1)
2(TOSC)(BRG + 1)
ns After this period, the
first clock pulse is
generated
2(TOSC)(BRG + 1)
TSU:STO Stop condition
Setup time
100 kHz mode
400 kHz mode
1 MHz mode(1) 2(TOSC)(BRG + 1)
2(TOSC)(BRG + 1)
ns
2(TOSC)(BRG + 1)
THD:STO Stop condition
Hold time
100 kHz mode
400 kHz mode
2(TOSC)(BRG + 1)
ns
2(TOSC)(BRG + 1)
1 MHz mode(1) 2(TOSC)(BRG + 1)
Note 1: Maximum pin capacitance = 10 pF for all I2C pins.
FIGURE 25-18:
SSP I2C BUS DATA TIMING
103
102
100
101
109
SCL
90
106
91
92
107
SDA
In
110
109
SDA
Out
Note: Refer to Figure 25-4 for load conditions.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 367
PIC18F2331/2431/4331/4431
TABLE 25-18: SSP I2C BUS DATA REQUIREMENTS
Param.
Symbol
Characteristic
Min
Max Units
Conditions
No.
100
THIGH
Clock high time 100 kHz mode
400 kHz mode
2(TOSC)(BRG + 1)
2(TOSC)(BRG + 1)
—
—
ms
ms
ms
ms
ms
ms
ns
1 MHz mode(1) 2(TOSC)(BRG + 1)
—
101
102
103
90
TLOW
TR
Clock low time
100 kHz mode
400 kHz mode
2(TOSC)(BRG + 1)
2(TOSC)(BRG + 1)
—
—
1 MHz mode(1) 2(TOSC)(BRG + 1)
—
SDA and SCL
rise time
100 kHz mode
400 kHz mode
1 MHz mode(1)
100 kHz mode
400 kHz mode
1 MHz mode(1)
100 kHz mode
400 kHz mode
—
1000
300
300
300
300
100
—
CB is specified to be from
10 to 400 pF
20 + 0.1 CB
ns
—
—
ns
TF
SDA and SCL
fall time
ns
CB is specified to be from
10 to 400 pF
20 + 0.1 CB
—
ns
ns
TSU:STA Start condition
setup time
2(TOSC)(BRG + 1)
2(TOSC)(BRG + 1)
ms Only relevant for
Repeated Start
—
ms
condition
ms
1 MHz mode(1) 2(TOSC)(BRG + 1)
—
91
THD:STA Start condition
hold time
100 kHz mode
400 kHz mode
2(TOSC)(BRG + 1)
2(TOSC)(BRG + 1)
—
ms After this period, the first
clock pulse is generated
—
ms
1 MHz mode(1) 2(TOSC)(BRG + 1)
—
ms
ns
106
107
92
THD:DAT Data input
hold time
100 kHz mode
400 kHz mode
1 MHz mode(1)
100 kHz mode
400 kHz mode
1 MHz mode(1)
100 kHz mode
400 kHz mode
0
—
0
0.9
—
ms
ns
TBD
250
TSU:DAT Data input
setup time
—
ns
ns
(Note 2)
100
—
TBD
—
ns
TSU:STO Stop condition
setup time
2(TOSC)(BRG + 1)
2(TOSC)(BRG + 1)
—
ms
ms
ms
ns
—
1 MHz mode(1) 2(TOSC)(BRG + 1)
—
109
110
D102
TAA
TBUF
CB
Output validfrom 100 kHz mode
—
3500
1000
—
clock
400 kHz mode
1 MHz mode(1)
100 kHz mode
400 kHz mode
1 MHz mode(1)
—
—
ns
ns
Bus free time
4.7
1.3
TBD
—
—
ms Time the bus must be free
before a new transmission
—
ms
can start
ms
—
Bus capacitive loading
400
pF
Note 1: Maximum pin capacitance = 10 pF for all I2C pins.
2: A Fast mode I2C bus device can be used in a Standard mode I2C bus system, but parameter #107 ≥ 250 ns
must then be met. This will automatically be the case if the device does not stretch the LOW period of the
SCL signal. If such a device does stretch the LOW period of the SCL signal, it must output the next data bit
to the SDA line, parameter #102 + parameter #107 = 1000 + 250 = 1250 ns (for 100 kHz mode) before the
SCL line is released.
DS39616B-page 368
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
FIGURE 25-19:
USART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
RC6/TX/CK
pin
121
121
RC7/RX/DT
pin
120
Note: Refer to Figure 25-4 for load conditions.
122
TABLE 25-19: USART SYNCHRONOUS TRANSMISSION REQUIREMENTS
Param
Symbol
Characteristic
Min
Max
Units
Conditions
No.
120
TckH2dtV SYNC XMIT (MASTER & SLAVE)
Clock high to data out valid
PIC18FXX31
PIC18LFXX31
PIC18FXX31
PIC18LFXX31
PIC18FXX31
PIC18LFXX31
—
—
—
—
—
—
40
100
20
ns
ns
ns
ns
ns
ns
121
122
Tckrf
Tdtrf
Clock out rise time and fall time
(Master mode)
50
Data out rise time and fall time
20
50
FIGURE 25-20:
USART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
RC6/TX/CK
pin
125
RC7/RX/DT
pin
126
Note: Refer to Figure 25-4 for load conditions.
TABLE 25-20: USART SYNCHRONOUS RECEIVE REQUIREMENTS
Param.
Symbol
Characteristic
Min
Max
Units
Conditions
No.
125
TdtV2ckl SYNC RCV (MASTER & SLAVE)
Data hold before CK ↓ (DT hold time)
Data hold after CK ↓ (DT hold time)
10
15
—
—
ns
ns
126
TckL2dtl
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 369
PIC18F2331/2431/4331/4431
TABLE 25-21: A/D CONVERTER CHARACTERISTICS: PIC18F2331/2431/4331/4431 (INDUSTRIAL)
PIC18LF2331/2431/4331/4431 (INDUSTRIAL)
Param
Symbol
Characteristic
Min
Typ
Max
Units
Conditions
No.
Device Supply
AVDD
Analog VDD Supply
VDD-0.3
VSS-0.3
—
VDD+0.3
VSS+0.3
V
V
AVSS
IAD
Analog VSS Supply
Module Current
(during conversion)
500
250
µA
µA
VDD = 5V
VDD = 2.5V
IADO
Module Current Off
1.0
µA
AC Timing Parameters
A10
A11
A12
FTHR
Throughput rate
—
—
200
75
ksps VDD = 5V, single channel
ksps VDD < 3V, single channel
TAD
A/D Clock Period
385
1000
20,000
20,000
ns
VDD = 5V
VDD = 3V
TRC
A/D Internal RC Oscillator Period
500
750
10000
1500
2250
20000
ns
ns
ns
PIC18F parts
PIC18LF parts
AVDD < 3.0V
(1)
A13
A14
A16
TCNV
TACQ
TTC
Conversion Time
12
12
12
TAD
TAD
(2)
(2)
Acquisition Time
2
Conversion start from external
1/4 TCY
1Tcy
Reference Inputs
A20
VREF
Reference voltage for 10-bit
resolution
1.5
1.8
—
—
AVDD-AVSS
AVDD-AVSS
V
V
VDD ≥ 3V
VDD < 3V
(VREF+ - VREF-)
A21
A22
A23
VREFH
VREFL
IREF
Reference voltage High
(AVDD or VREF+)
1.5V
AVSS
—
—
AVDD
V
V
VDD ≥ 3V
Reference voltage Low
(AVSS or VREF-)
VREFH-1.5V
Reference Current
150µA
75µA
VDD = 5V
VDD = 2.5V
Analog Input Characteristics
(3)
A26
A30
VAIN
ZAIN
Input Voltage
AVSS-0.3
—
—
—
AVDD+0.3
2.5
V
Recommended impedance of
analog voltage source
kΩ
A31
ZCHIN
Analog channel input impedance
—
10.0
kΩ
VDD = 3.0 V
DC Performance
A41
A42
NR
EIL
Resolution
10 bits
—
—
Integral Nonlinearity
—
—
—
—
<
<
1
LSb VDD ≥ 3.0V
VREFH ≥ 3.0V
A43
A45
A46
A47
EIL
EOFF
EGA
—
Differential Nonlinearity
Offset error
—
0.5
1
LSb VDD ≥ 3.0V
VREFH ≥ 3.0V
<
1.5
1.5
LSb VDD ≥ 3.0V
VREFH ≥ 3.0V
Gain error
0.5
<
LSb VDD ≥ 3.0V
VREFH ≥ 3.0V
(4)
Monotonicity
guaranteed
—
VDD ≥ 3.0V
VREFH ≥ 3.0V
Note 1: Conversion time does not include acquisition time. See Section 20.0 “10-bit High-Speed Analog-to-Digital Converter
(A/D) Module” for a full discussion of acquisition time requirements.
2: In sequential modes, Tacq should be 12Tad or greater.
3: For VDD < 2.7V and temperature below 0°C, VAIN should be limited to range < VDD/2.
4: The A/D conversion result never decreases with an incraese in the input voltage, and has no missing codes.
DS39616B-page 370
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
26.0 PRELIMINARY DC AND AC
CHARACTERISTICS GRAPHS
AND TABLES
Graphs are not available at this time.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 371
PIC18F2331/2431/4331/4431
NOTES:
DS39616B-page 372
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
27.0 PACKAGING INFORMATION
27.1 Package Marking Information
28-Lead PDIP (Skinny DIP)
Example
XXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
YYWWNNN
PIC18F2331-I/SP
0317017
28-Lead SOIC
Example
XXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXX
PIC18F2431-E/SO
YYWWNNN
0310017
40-Lead PDIP
Example
Example
XXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXX
PIC18F4331-I/P
0312017
YYWWNNN
44-Lead TQFP
PIC18F4431
-I/PT
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
YYWWNNN
0320017
44-Lead QFN
Example
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
YYWWNNN
PIC18F4431
-I/ML
0320017
Legend: XX...X Customer specific information*
Y
Year code (last digit of calendar year)
YY
WW
NNN
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Note: In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line thus limiting the number of available characters
for customer specific information.
*
Standard PICmicro device marking consists of Microchip part number, year code, week code, and
traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check
with your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP
price.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 373
PIC18F2331/2431/4331/4431
27.2 Package Details
The following sections give the technical details of the packages.
28-Lead Skinny Plastic Dual In-line (SP) – 300 mil (PDIP)
E1
D
2
n
1
α
E
A2
L
A
c
B1
β
A1
eB
B
p
Units
INCHES*
NOM
MILLIMETERS
Dimension Limits
MIN
MAX
MIN
NOM
28
MAX
n
p
Number of Pins
Pitch
28
.100
.150
.130
2.54
3.81
3.30
Top to Seating Plane
Molded Package Thickness
Base to Seating Plane
Shoulder to Shoulder Width
Molded Package Width
Overall Length
A
A2
A1
E
.140
.160
3.56
4.06
.125
.015
.300
.275
1.345
.125
.008
.040
.016
.320
.135
3.18
0.38
7.62
6.99
34.16
3.18
0.20
1.02
3.43
.310
.285
1.365
.130
.012
.053
.019
.350
10
.325
.295
1.385
.135
.015
.065
.022
.430
15
7.87
7.24
8.26
7.49
35.18
3.43
0.38
1.65
0.56
10.92
15
E1
D
34.67
3.30
Tip to Seating Plane
Lead Thickness
L
c
0.29
Upper Lead Width
B1
B
1.33
Lower Lead Width
0.41
8.13
5
0.48
8.89
10
Overall Row Spacing
Mold Draft Angle Top
Mold Draft Angle Bottom
§
eB
α
5
β
5
10
15
5
10
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimension D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MO-095
Drawing No. C04-070
DS39616B-page 374
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
28-Lead Plastic Small Outline (SO) – Wide, 300 mil (SOIC)
E
E1
p
D
B
2
1
n
h
α
45°
c
A2
A
φ
β
L
A1
Units
INCHES*
NOM
MILLIMETERS
NOM
Dimension Limits
MIN
MAX
MIN
MAX
n
p
Number of Pins
Pitch
28
28
.050
.099
.091
.008
.407
.295
.704
.020
.033
4
1.27
2.50
2.31
0.20
10.34
7.49
17.87
0.50
0.84
4
Overall Height
A
.093
.104
2.36
2.64
Molded Package Thickness
Standoff
A2
A1
E
.088
.004
.394
.288
.695
.010
.016
0
.094
.012
.420
.299
.712
.029
.050
8
2.24
0.10
10.01
7.32
17.65
0.25
0.41
0
2.39
0.30
10.67
7.59
18.08
0.74
1.27
8
§
Overall Width
Molded Package Width
Overall Length
E1
D
Chamfer Distance
Foot Length
h
L
φ
Foot Angle Top
c
Lead Thickness
Lead Width
.009
.014
0
.011
.017
12
.013
.020
15
0.23
0.36
0
0.28
0.42
12
0.33
0.51
15
B
α
β
Mold Draft Angle Top
Mold Draft Angle Bottom
0
12
15
0
12
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-013
Drawing No. C04-052
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 375
PIC18F2331/2431/4331/4431
40-Lead Plastic Dual In-line (P) – 600 mil (PDIP)
E1
D
2
α
n
1
E
A2
A
L
c
B1
B
β
A1
p
eB
Units
INCHES*
NOM
MILLIMETERS
Dimension Limits
MIN
MAX
MIN
NOM
40
MAX
n
p
Number of Pins
Pitch
40
.100
.175
.150
2.54
Top to Seating Plane
A
.160
.190
.160
4.06
3.56
4.45
3.81
4.83
4.06
Molded Package Thickness
Base to Seating Plane
Shoulder to Shoulder Width
Molded Package Width
Overall Length
A2
A1
E
.140
.015
.595
.530
2.045
.120
.008
.030
.014
.620
5
0.38
15.11
13.46
51.94
3.05
0.20
0.76
0.36
15.75
5
.600
.545
2.058
.130
.012
.050
.018
.650
10
.625
.560
2.065
.135
.015
.070
.022
.680
15
15.24
13.84
52.26
3.30
0.29
1.27
0.46
16.51
10
15.88
14.22
52.45
3.43
0.38
1.78
0.56
17.27
15
E1
D
Tip to Seating Plane
Lead Thickness
L
c
Upper Lead Width
B1
B
Lower Lead Width
Overall Row Spacing
Mold Draft Angle Top
§
eB
α
β
Mold Draft Angle Bottom
* Controlling Parameter
§ Significant Characteristic
5
10
15
5
10
15
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MO-011
Drawing No. C04-016
DS39616B-page 376
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
44-Lead Plastic Thin Quad Flatpack (PT) 10x10x1 mm Body, 1.0/0.10 mm Lead Form (TQFP)
E
E1
#leads=n1
p
D1
D
2
1
B
n
°
CH x 45
α
A
c
φ
β
A1
A2
L
(F)
Units
INCHES
NOM
MILLIMETERS*
Dimension Limits
MIN
MAX
MIN
NOM
44
MAX
n
p
Number of Pins
Pitch
44
.031
11
0.80
11
Pins per Side
Overall Height
n1
A
.039
.037
.002
.018
.043
.039
.004
.024
.039
3.5
.047
1.00
0.95
1.10
1.00
0.10
0.60
1.20
Molded Package Thickness
Standoff
A2
A1
L
(F)
φ
.041
.006
.030
1.05
0.15
0.75
§
0.05
0.45
1.00
0
Foot Length
Footprint (Reference)
Foot Angle
0
.463
.463
.390
.390
.004
.012
.025
5
7
.482
.482
.398
.398
.008
.017
.045
15
3.5
12.00
12.00
10.00
10.00
0.15
0.38
0.89
10
7
12.25
12.25
10.10
10.10
0.20
0.44
1.14
15
Overall Width
E
D
.472
.472
.394
.394
.006
.015
.035
10
11.75
11.75
9.90
9.90
0.09
0.30
0.64
5
Overall Length
Molded Package Width
Molded Package Length
Lead Thickness
E1
D1
c
Lead Width
B
CH
α
Pin 1 Corner Chamfer
Mold Draft Angle Top
Mold Draft Angle Bottom
β
5
10
15
5
10
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D1 and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-026
Drawing No. C04-076
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 377
PIC18F2331/2431/4331/4431
44-Lead Plastic Quad Flat No Lead Package (ML) 8x8 mm Body (QFN)
EXPOSED
E
METAL
PAD
p
D
D2
2
1
B
n
PIN 1
INDEX ON
OPTIONAL PIN 1
INDEX ON
TOP MARKING
E2
L
EXPOSED PAD
TOP VIEW
BOTTOM VIEW
A
A1
A3
Units
INCHES
MILLIMETERS*
NOM
Dimension Limits
MIN
NOM
MAX
MIN
MAX
n
p
Number of Pins
Pitch
44
44
.026 BSC
.035
0.65 BSC
Overall Height
Standoff
A
A1
A3
E
.031
.000
.039
0.80
0.90
0.02
1.00
.001
.002
0
0.05
Base Thickness
Overall Width
Exposed Pad Width
Overall Length
Exposed Pad Length
Lead Width
.010 REF
.315 BSC
.268
0.25 REF
8.00 BSC
6.80
E2
D
.262
.274
6.65
6.95
.315 BSC
.268
8.00 BSC
6.80
D2
B
.262
.012
.014
.274
.013
.018
6.65
0.30
0.35
6.95
0.35
0.45
.013
0.33
Lead Length
L
.016
0.40
*Controlling Parameter
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed .010" (0.254mm) per side.
JEDEC equivalent: M0-220
Drawing No. C04-103
DS39616B-page 378
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
APPENDIX A: REVISION HISTORY
APPENDIX B: DEVICE
DIFFERENCES
Revision A (June 2003)
The differences between the devices listed in this data
sheet are shown in Table B-1.
Original data sheet for PIC18F2331/2431/4331/4431
devices.
Revision B (December 2003)
The Electrical Specifications in Section 25.0 “Electri-
cal Characteristics” have been updated and there
have been minor corrections to the data sheet text.
TABLE B-1:
DEVICE DIFFERENCES
Features
PIC18F2331
PIC18F2431
PIC18F4331
PIC18F4431
Program Memory (Bytes)
Program Memory (Instructions)
Interrupt Sources
4096
2048
22
8192
4096
22
4096
2048
34
8192
4096
34
I/O Ports
Ports A, B, C, D, E Ports A, B, C, D, E Ports A, B, C, D, E Ports A, B, C, D, E
Capture/Compare/PWM Modules
2
1
2
1
2
1
2
1
Enhanced Capture/Compare/
PWM Modules
Parallel Communications (PSP)
10-bit Analog-to-Digital Module
No
No
Yes
Yes
5 input channels
5 input channels
9 input channels
9 input channels
40-pin DIP
44-pin TQFP
44-pin QFN
40-pin DIP
44-pin TQFP
44-pin QFN
28-pin SDIP
28-pin SOIC
28-pin SDIP
28-pin SOIC
Packages
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 379
PIC18F2331/2431/4331/4431
APPENDIX C: CONVERSION
CONSIDERATIONS
APPENDIX D: MIGRATION FROM
BASELINE TO
ENHANCED DEVICES
This appendix discusses the considerations for
converting from previous versions of a device to the
ones listed in this data sheet. Typically, these changes
are due to the differences in the process technology
used. An example of this type of conversion is from a
PIC16C74A to a PIC16C74B.
This section discusses how to migrate from a baseline
device (i.e., PIC16C5X) to an enhanced MCU device
(i.e., PIC18FXXX).
The following are the list of modifications over the
PIC16C5X microcontroller family:
Not Applicable
Not Currently Available
DS39616B-page 380
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
APPENDIX E: MIGRATION FROM
APPENDIX F: MIGRATION FROM
HIGH-END TO
MID-RANGE TO
ENHANCED DEVICES
ENHANCED DEVICES
A detailed discussion of the differences between the
mid-range MCU devices (i.e., PIC16CXXX) and the
enhanced devices (i.e., PIC18FXXX) is provided in
AN716, “Migrating Designs from PIC16C74A/74B to
PIC18F442.” The changes discussed, while device
specific, are generally applicable to all mid-range to
enhanced device migrations.
A detailed discussion of the migration pathway and
differences between the high-end MCU devices (i.e.,
PIC17CXXX) and the enhanced devices (i.e.,
PIC18FXXX) is provided in AN726, “PIC17CXXX to
PIC18FXXX Migration.”
This Application Note is available on Microchip’s web
site; www.Microchip.com.
This Application Note is available on Microchip’s web
site; www.Microchip.com.
2003 Microchip Technology Inc.
Preliminary
DS39616B-page 381
PIC18F2331/2431/4331/4431
NOTES:
DS39616B-page 382
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
INDEX
RC3 Pin ................................................................... 120
RC4 Pin ................................................................... 120
A
A/D ................................................................................... 243
Associated Registers ............................................... 259
Calculating the Minimum Required
Acquisition Time ............................................... 254
Special Event Trigger (CCP) .................................... 154
Absolute Maximum Ratings ............................................. 337
AC (Timing) Characteristics ............................................. 353
Load Conditions for Device
Timing Specifications ....................................... 354
Parameter Symbology ............................................. 353
Temperature and Voltage Specifications ................. 354
Timing Conditions .................................................... 354
Access Bank ...................................................................... 70
ACK Pulse ................................................................ 217, 218
ADDLW ............................................................................ 293
ADDWF ............................................................................ 293
ADDWFC ......................................................................... 294
Analog-to-Digital Converter. See A/D.
RC6 Pin ................................................................... 121
RC7 Pin ................................................................... 122
RD0 Pin ................................................................... 127
RD1 Pin ................................................................... 127
RD2 Pin ................................................................... 126
RD3 Pin ................................................................... 126
RD4 Pin ................................................................... 125
RD5 Pin ................................................................... 125
RD7:RD6 Pins ......................................................... 124
RE2:RE0 Pins .......................................................... 130
RE3 Pin ................................................................... 130
Reads from Flash Program Memory .......................... 79
2
SSP (I C Mode) ....................................................... 217
SSP (SPI Mode) ...................................................... 214
System Clock ............................................................. 27
Table Read Operation ............................................... 75
Table Write Operation ................................................ 76
Table Writes to Flash Program Memory .................... 81
Timer0 in 16-bit Mode .............................................. 134
Timer0 in 8-bit Mode ................................................ 134
Timer1 ..................................................................... 138
Timer1 (16-bit Read/Write Mode) ............................ 138
Timer2 ..................................................................... 144
Timer5 ..................................................................... 146
USART Receive ....................................................... 233
USART Transmit ...................................................... 231
Watchdog Timer ...................................................... 278
BN .................................................................................... 296
BNC ................................................................................. 297
BNN ................................................................................. 297
BNOV ............................................................................... 298
BNZ .................................................................................. 298
BOR. See Brown-out Reset.
BOV ................................................................................. 301
BRA ................................................................................. 299
Break Character (12-bit) Transmit and Receive .............. 236
Brown-out Reset (BOR) ..............................................46, 267
BSF .................................................................................. 299
BTFSC ............................................................................. 300
BTFSS ............................................................................. 300
BTG ................................................................................. 301
BZ .................................................................................... 302
ANDLW ............................................................................ 294
ANDWF ............................................................................ 295
Application Notes
2
AN578 (Use of the SSP Module in the I C
Multi-Master Environment) ............................... 211
Assembler
MPASM Assembler .................................................. 331
Auto-Wake-up on Sync Break Character ......................... 235
B
Bank Select Register (BSR) ............................................... 70
BC .................................................................................... 295
BCF .................................................................................. 296
BF bit ................................................................................ 212
Block Diagrams
Analog Input Model .................................................. 254
Capture Mode Operation ......................................... 153
Compare Mode Operation ....................................... 154
External Power-on Reset Circuit
(Slow VDD Power-up) ......................................... 46
Fail-Safe Clock Monitor ............................................ 281
Generic I/O Port ....................................................... 107
Interrupt Logic ............................................................ 92
Low-Voltage Detect (LVD) ....................................... 262
Low-Voltage Detect (LVD) with External Input ......... 262
On-Chip Reset Circuit ................................................ 45
PIC18F2331/2431 ...................................................... 10
PIC18F4331/4431 ...................................................... 11
PLL ............................................................................. 22
PWM (Standard) ...................................................... 156
RA0 Pin .................................................................... 108
RA1 Pin .................................................................... 108
RA3:RA2 Pins .......................................................... 108
RA4 Pin .................................................................... 109
RA5 Pin .................................................................... 110
RA6 Pin .................................................................... 110
RB3:RB0 Pins .......................................................... 113
RB4 Pin .................................................................... 114
RB5 Pin ............................................................ 115, 121
RB7:RB6 Pins .......................................................... 116
RC0 Pin .................................................................... 118
RC1 Pin .................................................................... 119
RC2 Pin .................................................................... 119
C
C Compilers
MPLAB C17 ............................................................. 332
MPLAB C18 ............................................................. 332
MPLAB C30 ............................................................. 332
CALL ................................................................................ 302
Capture (CCP Module) .................................................... 153
Associated Registers ............................................... 155
CCP Pin Configuration ............................................. 153
CCPR1H:CCPR1L Registers ................................... 153
Software Interrupt .................................................... 153
Timer1 Mode Selection ............................................ 153
Capture/Compare/PWM (CCP) ....................................... 151
Capture Mode. See Capture.
CCP1 ....................................................................... 152
CCPR1H Register ........................................... 152
CCPR1L Register ............................................ 152
2003 Microchip Technology Inc.
DS39616B-page 383
PIC18F2331/2431/4331/4431
CCP2 ........................................................................152
CCPR2H Register ............................................152
CCPR2L Register ............................................152
Compare Mode. See Compare.
Operation During Code-Protect ................................. 88
Protection Against Spurious Write ............................. 87
Reading ..................................................................... 87
Using .......................................................................... 88
Write Verify ................................................................ 87
Writing ........................................................................ 87
Data Memory ..................................................................... 63
General Purpose Registers ....................................... 63
Map for PIC18F2X31/4X31 ........................................ 64
Special Function Registers ........................................ 65
Data/Address Bit (D/A) ..................................................... 212
DAW ................................................................................ 306
DC and AC Characteristics
Graphs and Tables (Preliminary) ............................. 371
DC Characteristics ............................................339, 340, 349
DCFSNZ .......................................................................... 307
DECF ............................................................................... 306
DECFSZ .......................................................................... 307
Demonstration Boards
PICDEM 1 ................................................................ 334
PICDEM 17 .............................................................. 334
PICDEM 18R PIC18C601/801 ................................. 335
PICDEM 2 Plus ........................................................ 334
PICDEM 3 PIC16C92X ............................................ 334
PICDEM 4 ................................................................ 334
PICDEM LIN PIC16C43X ........................................ 335
PICDEM USB PIC16C7X5 ...................................... 335
PICDEM.net Internet/Ethernet ................................. 334
Development Support ...................................................... 331
Device Differences ........................................................... 379
Device Overview .................................................................. 7
Features (table) ........................................................... 9
New Core Features ...................................................... 7
Other Special Features ................................................ 8
Direct Addressing ............................................................... 72
PWM Mode. See PWM.
Timer Resources ......................................................152
CKE bit .............................................................................212
CKP bit .............................................................................213
Clock Sources ....................................................................26
Selection Using OSCCON Register ...........................26
Clocking Scheme/Instruction Cycle ....................................61
CLRF ................................................................................303
CLRWDT ..........................................................................303
Code Examples
16 x 16 Signed Multiply Routine .................................90
16 x 16 Unsigned Multiply Routine .............................90
8 x 8 Signed Multiply Routine .....................................89
8 x 8 Unsigned Multiply Routine .................................89
Changing Between Capture Prescalers ...................153
Computed GOTO Using an Offset Value ...................63
Data EEPROM Read .................................................87
Data EEPROM Refresh Routine ................................88
Data EEPROM Write ..................................................87
Erasing a Flash Program Memory Row .....................80
Fast Register Stack ....................................................60
How to Clear RAM (Bank 1) Using Indirect
Addressing .........................................................71
Implementing a Real-Time Clock Using a
Timer1 Interrupt Service ..................................141
Initializing PORTA ....................................................107
Initializing PORTB ....................................................112
Initializing PORTC ....................................................118
Initializing PORTD ....................................................124
Initializing PORTE ....................................................129
Reading a Flash Program Memory Word ...................79
Saving Status, WREG and
E
BSR Registers in RAM .....................................106
Writing to Flash Program Memory ....................... 82–83
Code Protection ....................................................... 267, 283
COMF ...............................................................................304
Compare (CCP Module) ...................................................154
Associated Registers ...............................................155
CCP Pin Configuration .............................................154
CCPR1 Register .......................................................154
Software Interrupt .....................................................154
Special Event Trigger ...............................................154
Timer1 Mode Selection ............................................154
Computed GOTO ...............................................................63
Configuration Bits .............................................................267
Configuration Register Protection ....................................286
Context Saving During Interrupts .....................................106
Control Registers
Effects of Power Managed Modes on Various
Clock Sources ............................................................ 29
Electrical Characteristics .................................................. 337
Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (USART) ................................ 221
Equations
16 x 16 Signed Multiplication Algorithm ..................... 90
16 x 16 Unsigned Multiplication Algorithm ................. 90
A/D Acquisition Time ............................................... 253
A/D Minimum Charging Time ................................... 253
Errata ................................................................................... 6
Evaluation and Programming Tools ................................. 335
External Clock Input ........................................................... 23
F
Fail-Safe Clock Monitor .............................................267, 281
Interrupts in Power-Managed Modes ....................... 282
POR or Wake from Sleep ........................................ 282
WDT During Oscillator Failure ................................. 281
Fast Register Stack ............................................................ 60
Firmware Instructions ....................................................... 287
Flash Program Memory ..................................................... 75
Associated Registers ................................................. 83
Control Registers ....................................................... 76
Erase Sequence ........................................................ 80
Erasing ....................................................................... 80
Operation During Code-Protect ................................. 83
Reading ..................................................................... 79
TABLAT Register ....................................................... 78
EECON1 and EECON2 ..............................................76
Conversion Considerations ..............................................380
CPFSEQ ..........................................................................304
CPFSGT ...........................................................................305
CPFSLT ...........................................................................305
Crystal Oscillator/Ceramic Resonator ................................21
D
D/A Bit ..............................................................................212
Data EEPROM Code Protection ......................................286
Data EEPROM Memory .....................................................85
Associated Registers .................................................88
EEADR Register ........................................................85
EECON1 and EECON2 Registers .............................85
DS39616B-page 384
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
Table Pointer .............................................................. 78
BZ ............................................................................ 302
CALL ........................................................................ 302
CLRF ....................................................................... 303
CLRWDT ................................................................. 303
COMF ...................................................................... 304
CPFSEQ .................................................................. 304
CPFSGT .................................................................. 305
CPFSLT ................................................................... 305
DAW ........................................................................ 306
DCFSNZ .................................................................. 307
DECF ....................................................................... 306
DECFSZ .................................................................. 307
GOTO ...................................................................... 308
INCF ........................................................................ 308
INCFSZ .................................................................... 309
INFSNZ .................................................................... 309
IORLW ..................................................................... 310
IORWF ..................................................................... 310
LFSR ....................................................................... 311
MOVF ...................................................................... 311
MOVFF .................................................................... 312
MOVLB .................................................................... 312
MOVLW ................................................................... 313
MOVWF ................................................................... 313
MULLW .................................................................... 314
MULWF .................................................................... 314
NEGF ....................................................................... 315
NOP ......................................................................... 315
POP ......................................................................... 316
PUSH ....................................................................... 316
RCALL ..................................................................... 317
RESET ..................................................................... 317
RETFIE .................................................................... 318
RETLW .................................................................... 318
RETURN .................................................................. 319
RLCF ....................................................................... 319
RLNCF ..................................................................... 320
RRCF ....................................................................... 320
RRNCF .................................................................... 321
SETF ....................................................................... 321
SLEEP ..................................................................... 322
SUBFWB ................................................................. 322
SUBLW .................................................................... 323
SUBWF .................................................................... 323
SUBWFB ................................................................. 324
SWAPF .................................................................... 325
TBLRD ..................................................................... 326
TBLWT .................................................................... 327
TSTFSZ ................................................................... 328
XORLW ................................................................... 328
XORWF ................................................................... 329
Summary Table ....................................................... 290
Instructions in Program Memory ........................................ 62
Two-Word Instructions ............................................... 62
INTCON Register
Boundaries Based on Operation ........................ 78
Table Pointer Boundaries .......................................... 78
Table Reads and Table Writes .................................. 75
Unexpected Termination of Write Operation .............. 83
Write Verify ................................................................ 83
Writing to .................................................................... 81
FSCM. See Fail-Safe Clock Monitor.
G
GOTO ............................................................................... 308
H
Hardware Multiplier ............................................................ 89
Introduction ................................................................ 89
Operation ................................................................... 89
Performance Comparison .......................................... 89
HSPLL ................................................................................ 22
I
I/O Ports ........................................................................... 107
I C Mode
2
Addressing ............................................................... 218
Associated Registers ............................................... 220
Master Mode ............................................................ 220
Mode Selection ........................................................ 217
Multi-Master Mode ................................................... 220
Operation ................................................................. 217
Reception ................................................................. 218
Slave Mode
SCL and SDA Pins ........................................... 217
Transmission ............................................................ 219
ID Locations ............................................................. 267, 286
INCF ................................................................................. 308
INCFSZ ............................................................................ 309
In-Circuit Debugger .......................................................... 286
In-Circuit Serial Programming (ICSP) ...................... 267, 286
Indirect Addressing
INDF and FSR Registers ........................................... 71
Operation ................................................................... 71
Indirect Addressing Operation ............................................ 72
Indirect File Operand .......................................................... 63
INFSNZ ............................................................................ 309
Initialization Conditions for all Registers ...................... 48–51
Instruction Cycle ................................................................. 61
Instruction Flow/Pipelining ................................................. 61
Instruction Format ............................................................ 289
Instruction Set .................................................................. 287
ADDLW .................................................................... 293
ADDWF .................................................................... 293
ADDWFC ................................................................. 294
ANDLW .................................................................... 294
ANDWF .................................................................... 295
BC ............................................................................ 295
BCF .......................................................................... 296
BN ............................................................................ 296
BNC ......................................................................... 297
BNN ......................................................................... 297
BNOV ....................................................................... 298
BNZ .......................................................................... 298
BOV ......................................................................... 301
BRA .......................................................................... 299
BSF .......................................................................... 299
BTFSC ..................................................................... 300
BTFSS ..................................................................... 300
BTG .......................................................................... 301
RBIF Bit ................................................................... 112
INTCON Registers ............................................................. 93
2
2
Inter-Integrated Circuit (I C). See I C Mode.
Internal Oscillator Block ..................................................... 24
Adjustment ................................................................. 24
INTIO Modes ............................................................. 24
INTRC Output Frequency .......................................... 24
OSCTUNE Register ................................................... 24
Internal RC Oscillator
Use with WDT .......................................................... 278
2003 Microchip Technology Inc.
DS39616B-page 385
PIC18F2331/2431/4331/4431
Interrupt Sources ..............................................................267
O
Capture Complete (CCP) .........................................153
Opcode Field Descriptions ............................................... 288
OPTION_REG Register
Compare Complete (CCP) .......................................154
Interrupt-on-Change (RB7:RB4) ..............................112
INTn Pin ...................................................................106
PORTB, Interrupt-on-Change ..................................106
TMR0 .......................................................................106
TMR1 Overflow ........................................................137
TMR2 to PR2 Match .................................................144
TMR2 to PR2 Match (PWM) ............................ 143, 156
Interrupts ............................................................................91
Interrupts, Enable Bits
PSA Bit .................................................................... 135
T0CS Bit .................................................................. 135
T0PS2:T0PS0 Bits ................................................... 135
T0SE Bit ................................................................... 135
Oscillator Configuration ...................................................... 21
EC .............................................................................. 21
ECIO .......................................................................... 21
HS .............................................................................. 21
HSPLL ....................................................................... 21
Internal Oscillator Block ............................................. 24
INTIO1 ....................................................................... 21
INTIO2 ....................................................................... 21
LP .............................................................................. 21
RC .............................................................................. 21
RCIO .......................................................................... 21
XT .............................................................................. 21
Oscillator Selection .......................................................... 267
Oscillator Start-up Timer (OST) ....................................29, 46
Oscillator Switching ............................................................ 26
Oscillator Transitions ......................................................... 28
Oscillator, Timer1 ............................................................. 137
CCP1 Enable (CCP1IE Bit) ......................................153
Interrupts, Flag Bits
CCP1 Flag (CCP1IF Bit) ..........................................153
CCP1IF Flag (CCP1IF Bit) .......................................154
Interrupt-on-Change (RB7:RB4) Flag (RBIF Bit) ......112
INTOSC Frequency Drift ....................................................42
INTOSC, INTRC. See Internal Oscillator Block.
IORLW .............................................................................310
IORWF .............................................................................310
IPR Registers ...................................................................102
L
LFSR ................................................................................311
Look-up Tables ..................................................................63
Low-Voltage Detect ..........................................................261
Low-Voltage Detect
Characteristics .........................................................352
Effects of a Reset .....................................................265
Operation .................................................................264
Current Consumption .......................................265
Reference Voltage Set Point ............................265
Operation During Sleep ............................................265
Low-Voltage ICSP Programming .....................................286
LVD. See Low-Voltage Detect.
P
P (Stop) bit ....................................................................... 212
Packaging Information ..................................................... 373
Marking .................................................................... 373
PICkit 1 Flash Starter Kit .................................................. 335
PICSTART Plus Development Programmer .................... 333
PIE Registers ..................................................................... 99
Pin Functions
MCLR/VPP/RE3 ....................................................12, 15
OSC1/CLKI/RA7 ...................................................12, 15
OSC2/CLKO/RA6 .................................................12, 15
RA0/AN0 ...............................................................12, 15
RA1/AN1 ...............................................................12, 15
RA2/AN2/VREF-/CAP1/INDX ................................12, 15
RA3/AN3/VREF+/CAP2/QEA .................................12, 15
RA4/AN4/CAP3/QEB ................................................. 15
RA4/CAP3/QEB ......................................................... 12
RA5/AN5/LVDIN ........................................................ 15
RB0/PWM0 ...........................................................13, 16
RB1/PWM1 ...........................................................13, 16
RB2/PWM2 ...........................................................13, 16
RB3/PWM3 ...........................................................13, 16
RB4/KBI0/PWM5 ....................................................... 16
RB4/PWM5 ................................................................ 13
RB5/KBI1/PWM4/PGM .........................................13, 16
RB6/KBI2/PGC .....................................................13, 16
RB7/KBI3/PGD .....................................................13, 16
RC0/T1OSO/T1CKI ..............................................14, 17
RC1/T1OSI/CCP2/FLTA .......................................14, 17
RC2/CCP1/FLTB ..................................................14, 17
RC3/T0CKI/T5CKI/INT0 .......................................14, 17
RC4/INT1/SDI/SDA ..............................................14, 17
RC5/INT2/SCK/SCL .............................................14, 17
RC6/TX/CK/SS .....................................................14, 17
RC7/RX/DT/SDO ..................................................14, 17
RD0/T0CKI/T5CKI ..................................................... 18
RD1/SDO ................................................................... 18
RD2/SDI/SDA ............................................................ 18
RD3/SCK/SCL ........................................................... 18
RD4/FLTA .................................................................. 18
M
Memory Organization .........................................................57
Data Memory ..............................................................63
Program Memory .......................................................57
Memory Programming Requirements ..............................351
Migration from Baseline to Enhanced Devices ................380
Migration from High-End to Enhanced Devices ...............381
Migration from Mid-Range to Enhanced Devices .............381
MOVF ...............................................................................311
MOVFF .............................................................................312
MOVLB .............................................................................312
MOVLW ............................................................................313
MOVWF ...........................................................................313
MPLAB ASM30 Assembler, Linker, Librarian ..................332
MPLAB ICD 2 In-Circuit Debugger ...................................333
MPLAB ICE 2000 High Performance Universal
In-Circuit Emulator ...................................................333
MPLAB ICE 4000 High Performance Universal I
n-Circuit Emulator ....................................................333
MPLAB Integrated Development
Environment Software ..............................................331
MPLINK Object Linker/MPLIB Object Librarian ...............332
MULLW ............................................................................314
MULWF ............................................................................314
N
NEGF ...............................................................................315
NOP .................................................................................315
DS39616B-page 386
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
RD5/PWM4 ................................................................ 18
Program Counter
PCL Register ............................................................. 60
PCLATH Register ...................................................... 60
PCLATU Register ...................................................... 60
Program Memory
RD6/PWM6 ................................................................ 18
RD7/PWM7 ................................................................ 18
RE0/AN6 .................................................................... 19
RE1/AN7 .................................................................... 19
RE2/AN8 .................................................................... 19
VDD ....................................................................... 14, 19
VSS ....................................................................... 14, 19
Pinout I/O Descriptions
PIC18F2331/2431 ...................................................... 12
PIC18F4331/4431 ...................................................... 15
PIR Registers ..................................................................... 96
PLL Lock Time-out ............................................................. 46
Pointer, FSRn ..................................................................... 71
POP .................................................................................. 316
POR. See Power-on Reset.
Interrupt Vector .......................................................... 57
Map and Stack
PIC18F2331/4331 ............................................. 57
PIC18F2431/4431 ............................................. 57
Reset Vector .............................................................. 57
Program Memory Code Protection .................................. 284
Program Verification ........................................................ 283
Program Verification and Code Protection
Associated Registers ............................................... 283
Programming, Device Instructions ................................... 287
Pulse Width Modulation. See PWM (CCP Module)
and PWM (ECCP Module).
PORTA
Associated Registers ............................................... 111
LATA Register .......................................................... 107
PORTA Register ...................................................... 107
TRISA Register ........................................................ 107
PORTB
Associated Registers ............................................... 117
LATB Register .......................................................... 112
PORTB Register ...................................................... 112
RB7:RB4 Interrupt-on-Change Flag (RBIF Bit) ........ 112
TRISB Register ........................................................ 112
PORTC
Associated Registers ............................................... 123
LATC Register ......................................................... 118
PORTC Register ...................................................... 118
TRISC Register ........................................................ 118
PORTD
PUSH ............................................................................... 316
PUSH and POP Instructions .............................................. 59
PWM (CCP Module) ........................................................ 156
Associated Registers ............................................... 157
CCPR1H:CCPR1L Registers ................................... 156
Duty Cycle ............................................................... 156
Example Frequencies/Resolutions .......................... 157
Period ...................................................................... 156
Set-up for PWM Operation ...................................... 157
TMR2 to PR2 Match .........................................143, 156
Q
Q Clock ............................................................................ 157
QEI Sampling Modes ....................................................... 172
R
R/W bit ..............................................................212, 218, 219
RAM. See Data Memory.
RC Oscillator ...................................................................... 23
RCIO Oscillator Mode ................................................ 23
RCALL ............................................................................. 317
RCON Register
Bit Status During Initialization .................................... 47
Bits and Positions ...................................................... 47
RCSTA Register
SPEN Bit .................................................................. 221
Receive Overflow Indicator Bit (SSPOV) ......................... 213
Register File ....................................................................... 63
Registers
Associated Registers ............................................... 128
LATD Register ......................................................... 124
PORTD Register ...................................................... 124
TRISD Register ........................................................ 124
PORTE
Associated Registers ............................................... 132
LATE Register .......................................................... 129
PORTE Register ...................................................... 129
TRISE Register ........................................................ 129
Postscaler, WDT
Assignment (PSA Bit) .............................................. 135
Rate Select (T0PS2:T0PS0 Bits) ............................. 135
Power-Managed Modes ..................................................... 31
Entering ...................................................................... 32
Idle Modes ................................................................. 33
Run Modes ................................................................. 38
Selecting .................................................................... 31
Sleep Mode ................................................................ 33
Summary (table) ........................................................ 31
Wake from .................................................................. 40
Power-on Reset (POR) .............................................. 46, 267
Oscillator Start-up Timer (OST) ......................... 46, 267
Power-up Timer (PWRT) ................................... 46, 267
Time-out Sequence .................................................... 46
Power-up Delays ................................................................ 29
Power-up Timer (PWRT) .............................................. 29, 46
Prescaler, Capture ........................................................... 153
Prescaler, Timer0 ............................................................. 135
Assignment (PSA Bit) .............................................. 135
Rate Select (T0PS2:T0PS0 Bits) ............................. 135
Prescaler, Timer2 ............................................................. 157
PRO MATE II Universal Device Programmer .................. 333
BAUDCTL (Baud Rate Control) ............................... 224
CCPxCON (Capture/Compare/PWM Control) ......... 151
CONFIG1H (Configuration 1 High) .......................... 268
CONFIG2H (Configuration 2 High) ...................270, 271
CONFIG2L (Configuration 2 Low) ........................... 269
CONFIG3H (Configuration 3 High) .......................... 272
CONFIG4L (Configuration 4 Low) ........................... 273
CONFIG5H (Configuration 5 High) .......................... 274
CONFIG6H (Configuration 6 High) .......................... 275
CONFIG6L (Configuration 6 Low) ........................... 275
CONFIG7H (Configuration 7 High) .......................... 276
CONFIG7L (Configuration 7 Low) ........................... 276
Device ID Register 1 ................................................ 277
Device ID Register 2 ................................................ 277
EECON1 (Data EEPROM Control 1) ....................77, 86
INTCON (Interrupt Control) ........................................ 93
INTCON2 (Interrupt Control 2) ................................... 94
INTCON3 (Interrupt Control 3) ................................... 95
IPR1 (Peripheral Interrupt Priority 1) ....................... 102
IPR2 (Peripheral Interrupt Priority 2) ....................... 103
2003 Microchip Technology Inc.
DS39616B-page 387
PIC18F2331/2431/4331/4431
LVDCON (LVD Control) ...........................................263
OSCCON (Oscillator Control) ....................................28
OSCTUNE (Oscillator Tuning) ...................................25
PIE1 (Peripheral Interrupt Enable 1) ..........................99
PIE2 (Peripheral Interrupt Enable 2) ........................100
PIR1 (Peripheral Interrupt Request (Flag) 1) .............96
PIR2 (Peripheral Interrupt Request (Flag) 2) .............97
RCON (Reset Control) ....................................... 74, 105
RCSTA (Receive Status and Control) ......................223
SSPCON (Sync Serial Port Control) Register ..........213
SSPSTAT (Sync Serial Port Status) Register ..........212
Status .........................................................................73
STKPTR (Stack Pointer) ............................................59
Summary .............................................................. 66–68
T0CON (Timer0 Control) ..........................................133
T1CON (Timer 1 Control) .........................................137
T2CON (Timer 2 Control) .........................................143
TRISE .......................................................................131
TXSTA (Transmit Status and Control) .....................222
WDTCON (Watchdog Timer Control) .......................278
Reset .......................................................................... 45, 317
Resets ..............................................................................267
RETFIE ............................................................................318
RETLW .............................................................................318
RETURN ..........................................................................319
Return Address Stack ........................................................58
Return Stack Pointer (STKPTR) ........................................58
Revision History ...............................................................379
RLCF ................................................................................319
RLNCF .............................................................................320
RRCF ...............................................................................320
RRNCF .............................................................................321
SSPM<3:0> Bits .............................................................. 213
SSPOV Bit ....................................................................... 213
Stack Full/Underflow Resets .............................................. 59
SUBFWB ......................................................................... 322
SUBLW ............................................................................ 323
SUBWF ............................................................................ 323
SUBWFB ......................................................................... 324
SWAPF ............................................................................ 325
Synchronous Serial Port Enable Bit (SSPEN) ................. 213
Synchronous Serial Port Mode Select Bits
(SSPM<3:0>) ........................................................... 213
Synchronous Serial Port. See SSP.
T
TABLAT Register ............................................................... 78
Table Pointer Operations (table) ........................................ 78
Table Reads/Table Writes ................................................. 63
TBLPTR Register ............................................................... 78
TBLRD ............................................................................. 326
TBLWT ............................................................................. 327
Time-out in Various Situations (table) ................................ 47
Timer0 .............................................................................. 133
16-bit Mode Timer Reads and Writes ...................... 135
Associated Registers ............................................... 135
Clock Source Edge Select (T0SE Bit) ..................... 135
Clock Source Select (T0CS Bit) ............................... 135
Interrupt ................................................................... 135
Operation ................................................................. 135
Prescaler. See Prescaler, Timer0.
Switching Prescaler Assignment ............................. 135
Timer1 .............................................................................. 137
16-bit Read/Write Mode ........................................... 140
Associated Registers ............................................... 141
Interrupt ................................................................... 140
Operation ................................................................. 138
Oscillator ...........................................................137, 139
Oscillator Layout Considerations ............................. 139
Overflow Interrupt .................................................... 137
Resetting, Using a Special Event Trigger
Output (CCP) ................................................... 140
Special Event Trigger (CCP) ................................... 154
TMR1H Register ...................................................... 137
TMR1L Register ....................................................... 137
Use as a Real-Time Clock ....................................... 140
Timer2 .............................................................................. 143
Associated Registers ............................................... 144
Operation ................................................................. 143
Postscaler. See Postscaler, Timer2.
PR2 Register ....................................................143, 156
Prescaler. See Prescaler, Timer2.
SSP Clock Shift ................................................143, 144
TMR2 Register ......................................................... 143
TMR2 to PR2 Match Interrupt ...................143, 144, 156
Timer5
S
S (Start) bit .......................................................................212
SCK ..................................................................................211
SCL ..................................................................................217
SDI ...................................................................................211
SDO .................................................................................211
Serial Clock (SCK) Pin .....................................................211
Serial Data In (SDI) Pin ....................................................211
Serial Data Out (SDO) Pin ...............................................211
SETF ................................................................................321
Slave Select (SS) Pin .......................................................211
Sleep ................................................................................322
OSC1 and OSC2 Pin States ......................................29
SMP bit .............................................................................212
Software Simulator (MPLAB SIM) ....................................332
Software Simulator (MPLAB SIM30) ................................332
Special Event Trigger. See Compare (CCP Module).
Special Features of the CPU ............................................267
Special Function Registers ................................................65
Map ............................................................................65
SPI Mode .........................................................................211
Associated Registers ...............................................216
Serial Clock ..............................................................211
Serial Data In ...........................................................211
Serial Data Out .........................................................211
Slave Select .............................................................211
SS ....................................................................................211
SSP
Block Diagram ......................................................... 146
Timing Diagrams
Asynchronous Reception ......................................... 234
Asynchronous Transmission .................................... 231
Asynchronous Transmission (Back to Back) ........... 231
Auto-Wake-up Bit (WUE) During
Normal Operation ............................................ 235
Auto-Wake-up Bit (WUE) During Sleep ................... 235
Brown-out Reset (BOR) ........................................... 358
Capture/Compare/PWM (CCP) ............................... 360
CLKO and I/O .......................................................... 357
Clock, Instruction Cycle ............................................. 61
Overview
TMR2 Output for Clock Shift ............................ 143, 144
2
SSP I C Operation ...........................................................217
Slave Mode ..............................................................217
SSPEN Bit ........................................................................213
DS39616B-page 388
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
2
Example SPI Master Mode (CKE = 0) ..................... 361
I C Bus Data Requirements (Slave Mode) .............. 366
2
Example SPI Master Mode (CKE = 1) ..................... 362
Example SPI Slave Mode (CKE = 0) ....................... 363
Example SPI Slave Mode (CKE = 1) ....................... 364
External Clock (All Modes except PLL) .................... 355
Fail-Safe Clock Monitor ............................................ 282
Master SSP I C Bus Data Requirements ................ 368
2
Master SSP I C Bus Start/Stop Bits
Requirements .................................................. 367
PLL Clock ................................................................ 356
RESET, Watchdog Timer, Oscillator Start-up
Timer, Power-up Timer and Brown-out
Reset Requirements ........................................ 358
Timer0 and Timer1 External Clock Requirements ... 359
USART Synchronous Receive Requirements ......... 369
USART Synchronous Transmission
2
I C Bus Data ............................................................ 365
2
I C Bus Start/Stop Bits ............................................. 365
2
I C Reception (7-bit Address) .................................. 219
2
I C Transmission (7-bit Address) ............................. 219
Low-Voltage Detect .................................................. 264
Low-Voltage Detect Characteristics ......................... 352
Requirements .................................................. 369
Top-of-Stack Access .......................................................... 58
TSTFSZ ........................................................................... 328
Two-Speed Start-up ..................................................267, 279
Two-Word Instructions
2
Master SSP I C Bus Data ........................................ 367
2
Master SSP I C Bus Start/Stop Bits ........................ 367
PWM Output ............................................................ 156
Reset, Watchdog Timer (WDT), Oscillator Start-up
Timer (OST), Power-up Timer (PWRT) ........... 358
Send Break Character Sequence ............................ 236
Slow Rise Time (MCLR Tied to VDD,
Example Cases .......................................................... 62
TXSTA Register
BRGH Bit ................................................................. 225
VDD Rise > TPWRT) ............................................ 55
SPI Mode (Master Mode) ......................................... 215
SPI Mode (Slave Mode with CKE = 0) ..................... 215
SPI Mode (Slave Mode with CKE = 1) ..................... 216
Synchronous Reception (Master Mode, SREN) ...... 239
Synchronous Transmission ...................................... 237
Synchronous Transmission (Through TXEN) .......... 238
Time-out Sequence on POR w/PLL Enabled
(MCLR Tied to VDD) ........................................... 55
Time-out Sequence on Power-up (MCLR Not
Tied to VDD): Case 1 .......................................... 54
Time-out Sequence on Power-up (MCLR Not
U
UA .................................................................................... 212
Update Address bit, UA ................................................... 212
USART
Asynchronous Mode ................................................ 230
12-bit Break Transmit and Receive ................. 236
Associated Registers, Receive ........................ 234
Associated Registers, Transmit ....................... 232
Auto-Wake-up on Sync Break ......................... 235
Receiver .......................................................... 233
Setting up 9-bit Mode with Address Detect ..... 233
Transmitter ...................................................... 230
Baud Rate Generator (BRG) ................................... 225
Associated Registers ....................................... 226
Auto-Baud Rate Detect .................................... 229
Baud Rate Error, Calculating ........................... 225
Baud Rates, Asynchronous Modes ................. 226
High Baud Rate Select (BRGH Bit) ................. 225
Power-Managed Mode Operation ................... 225
Sampling .......................................................... 225
Serial Port Enable (SPEN Bit) ................................. 221
Synchronous Master Mode ...................................... 237
Associated Registers, Reception ..................... 240
Associated Registers, Transmit ....................... 238
Reception ........................................................ 239
Transmission ................................................... 237
Synchronous Slave Mode ........................................ 241
Associated Registers, Receive ........................ 242
Associated Registers, Transmit ....................... 241
Reception ........................................................ 242
Transmission ................................................... 241
Tied to VDD): Case 2 .......................................... 54
Time-out Sequence on Power-up (MCLR
Tied to VDD, VDD Rise < TPWRT) ........................ 54
Timer0 and Timer1 External Clock .......................... 359
Transition for Entry to SEC_IDLE Mode .................... 36
Transition for Entry to SEC_RUN Mode .................... 38
Transition for Entry to Sleep Mode ............................ 34
Transition for Two-Speed Start-up
(INTOSC to HSPLL) ......................................... 280
Transition for Wake from RC_RUN Mode
(RC_RUN to NFP) ............................................. 37
Transition for Wake from SEC_RUN Mode
(Secondary Clock to HSPLL) ............................. 36
Transition for Wake from Sleep (HSPLL) ................... 34
Transition Timing For Wake From PRI_IDLE Mode ... 35
Transition Timing to PRI_IDLE Mode ........................ 35
Transition to RC_IDLE Mode ..................................... 37
Transition to RC_RUN Mode ..................................... 39
USART Synchronous Receive ( Master/Slave) ........ 369
USART SynchronousTransmission
(Master/Slave) .................................................. 369
Timing Diagrams and Specifications ................................ 355
Capture/Compare/PWM Requirements ................... 360
CLKO and I/O Requirements ................................... 357
DC Characteristics - Internal RC Accuracy .............. 356
Example SPI Mode Requirements
W
Watchdog Timer (WDT) ............................................267, 278
Associated Registers ............................................... 279
Control Register ....................................................... 278
During Oscillator Failure .......................................... 281
Programming Considerations .................................. 278
WCOL bit ......................................................................... 213
Write Collision Detect bit (WCOL) ................................... 213
WWW, On-Line Support ...................................................... 6
(Master Mode, CKE = 0) .................................. 361
Example SPI Mode Requirements
(Master Mode, CKE = 1) .................................. 362
Example SPI Mode Requirements
(Slave Mode, CKE = 0) .................................... 363
Example SPI Slave Mode Requirements
(CKE = 1) ......................................................... 364
External Clock Requirements .................................. 355
X
XORLW ............................................................................ 328
XORWF ........................................................................... 329
2003 Microchip Technology Inc.
DS39616B-page 389
PIC18F2331/2431/4331/4431
NOTES:
DS39616B-page 390
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
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SYSTEMS INFORMATION AND
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Connecting to the Microchip Internet
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2003 Microchip Technology Inc.
Preliminary
DS39616B-page 391
PIC18F2331/2431/4331/4431
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PIC18F2331/2431/4331/4431
DS39616B
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DS39616B-page 392
Preliminary
2003 Microchip Technology Inc.
PIC18F2331/2431/4331/4431
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO.
Device
X
/XX
XXX
Examples:
Temperature
Range
Package
Pattern
a) PIC18LF4431-I/P 301 = Industrial temp.,
PDIP package, Extended VDD limits,
QTP pattern #301.
b) PIC18LF2331-I/SO = Industrial temp.,
SOIC package, Extended VDD limits.
c) PIC18F4331-I/P = Industrial temp., PDIP
package, normal VDD limits.
(1)
Device
PIC18F2331/2431/4331/4431
,
(1,2)
PIC18F2331/2431/4331/4431T
;
VDD range 4.2V to 5.5V
(1)
PIC18LF2331/2431/4331/4431
,
(1,2)
PIC18LF2331/2431/4331/44310T
;
VDD range 2.0V to 5.5V
Temperature
Range
I
=
-40°C to +85°C (Industrial)
Note 1: F = Standard Voltage range
LF = Wide Voltage Range
Package
PT = TQFP (Thin Quad Flatpack)
SO = SOIC
2: T = in tape and reel - SOIC
and TQFP packages only.
SP = Skinny Plastic DIP
P
= PDIP
ML = QFN
Pattern
QTP, SQTP, Code or Special Requirements
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Preliminary
DS39616B-page 393
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11/24/03
DS39616B-page 394
Preliminary
2003 Microchip Technology Inc.
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MICROCHIP
PIC18F2331-I/P
28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High-Performance PWM and A/D
MICROCHIP
PIC18F2331-I/PT
28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High-Performance PWM and A/D
MICROCHIP
PIC18F2331-I/SO
28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High-Performance PWM and A/D
MICROCHIP
PIC18F2331-I/SP
28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High-Performance PWM and A/D
MICROCHIP
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