PIC16FF684-E/P [MICROCHIP]
14-Pin, Flash-Based 8-Bit CMOS Microcontrollers with nanoWatt Technology; 14引脚,基于闪存的8位CMOS微控制器采用纳瓦技术型号: | PIC16FF684-E/P |
厂家: | MICROCHIP |
描述: | 14-Pin, Flash-Based 8-Bit CMOS Microcontrollers with nanoWatt Technology |
文件: | 总192页 (文件大小:3274K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
PIC16F684
Data Sheet
14-Pin, Flash-Based 8-Bit
CMOS Microcontrollers
with nanoWatt Technology
© 2007 Microchip Technology Inc.
DS41202F
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 provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
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OTHERWISE, RELATED TO THE INFORMATION,
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conveyed, implicitly or otherwise, under any Microchip
intellectual property rights.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, KEELOQ, KEELOQ logo, microID, MPLAB, PIC,
PICmicro, PICSTART, PRO MATE, PowerSmart, rfPIC, and
SmartShunt are registered trademarks of Microchip
Technology Incorporated in the U.S.A. and other countries.
AmpLab, FilterLab, Linear Active Thermistor, Migratable
Memory, MXDEV, MXLAB, PS logo, SEEVAL, SmartSensor
and The Embedded Control Solutions Company are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, CodeGuard,
dsPICDEM, dsPICDEM.net, dsPICworks, ECAN,
ECONOMONITOR, FanSense, FlexROM, fuzzyLAB,
In-Circuit Serial Programming, ICSP, ICEPIC, Mindi, MiWi,
MPASM, MPLAB Certified logo, MPLIB, MPLINK, PICkit,
PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal,
PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB,
rfPICDEM, Select Mode, Smart Serial, SmartTel, Total
Endurance, UNI/O, WiperLock and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
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.
© 2007, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received ISO/TS-16949:2002 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona, Gresham, Oregon and Mountain View, California. The
Company’s quality system processes and procedures are for its PIC®
MCUs and dsPIC® DSCs, KEELOQ® code hopping devices, Serial
EEPROMs, microperipherals, nonvolatile memory and analog
products. In addition, Microchip’s quality system for the design and
manufacture of development systems is ISO 9001:2000 certified.
DS41202F-page ii
© 2007 Microchip Technology Inc.
PIC16F684
14-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology
High-Performance RISC CPU:
Low-Power Features:
• Only 35 instructions to learn:
- All single-cycle instructions except branches
• Operating speed:
• Standby Current:
- 50 nA @ 2.0V, typical
• Operating Current:
- DC – 20 MHz oscillator/clock input
- DC – 200 ns instruction cycle
- 11 μA @ 32 kHz, 2.0V, typical
- 220 μA @ 4 MHz, 2.0V, typical
• Interrupt capability
• Watchdog Timer Current:
• 8-level deep hardware stack
• Direct, Indirect and Relative Addressing modes
- 1 μA @ 2.0V, typical
Peripheral Features:
Special Microcontroller Features:
• 12 I/O pins with individual direction control:
• Precision Internal Oscillator:
- High current source/sink for direct LED drive
- Interrupt-on-change pin
- Individually programmable weak pull-ups
- Ultra Low-Power Wake-Up (ULPWU)
- Factory calibrated to ±1%, typical
- Software selectable frequency range of
8 MHz to 125 kHz
- Software tunable
• Analog Comparator module with:
- Two-Speed Start-up mode
- Two analog comparators
- Crystal fail detect for critical applications
- Clock mode switching during operation for
power savings
- Programmable on-chip voltage reference
(CVREF) module (% of VDD)
- Comparator inputs and outputs externally
accessible
• Software Selectable 31 kHz Internal Oscillator
• Power-Saving Sleep mode
• A/D Converter:
• Wide operating voltage range (2.0V-5.5V)
• Industrial and Extended Temperature range
• Power-on Reset (POR)
- 10-bit resolution and 8 channels
• Timer0: 8-bit timer/counter with 8-bit
programmable prescaler
• Power-up Timer (PWRT) and Oscillator Start-up
Timer (OST)
• Enhanced Timer1:
- 16-bit timer/counter with prescaler
- External Timer1 Gate (count enable)
- Option to use OSC1 and OSC2 in LP mode
as Timer1 oscillator if INTOSC mode
selected
• Brown-out Reset (BOR) with software control
option
• Enhanced low-current Watchdog Timer (WDT)
with on-chip oscillator (software selectable
nominal 268 seconds with full prescaler) with
software enable
• Timer2: 8-bit timer/counter with 8-bit period
register, prescaler and postscaler
• Multiplexed Master Clear with pull-up/input pin
• Programmable code protection
• Enhanced Capture, Compare, PWM module:
- 16-bit Capture, max resolution 12.5 ns
- Compare, max resolution 200 ns
- 10-bit PWM with 1, 2 or 4 output channels,
programmable “dead time”, max frequency
20 kHz
• High Endurance Flash/EEPROM cell:
- 100,000 write Flash endurance
- 1,000,000 write EEPROM endurance
- Flash/Data EEPROM retention: > 40 years
• In-Circuit Serial ProgrammingTM (ICSPTM) via two
pins
Program
Memory
Data Memory
10-bit A/D
(ch)
Timers
8/16-bit
Device
I/O
Comparators
Flash
(words)
SRAM
(bytes)
EEPROM
(bytes)
PIC16F684
2048
128
256
12
8
2
2/1
© 2007 Microchip Technology Inc.
DS41202F-page 1
PIC16F684
14-Pin Diagram (PDIP, SOIC, TSSOP)
VDD
RA5/T1CKI/OSC1/CLKIN
RA4/AN3/T1G/OSC2/CLKOUT
RA3/MCLR/VPP
1
2
3
4
5
6
7
VSS
14
13
12
11
10
9
RA0/AN0/C1IN+/ICSPDAT/ULPWU
RA1/AN1/C1IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RC0/AN4/C2IN+
RC5/CCP1/P1A
RC4/C2OUT/P1B
RC1/AN5/C2IN-
RC3/AN7/P1C
RC2/AN6/P1D
8
TABLE 1:
DUAL IN-LINE PIN SUMMARY
I/O
Pin
Analog
Comparators
Timer
CCP
Interrupts Pull-ups
Basic
RA0
13
12
11
AN0
AN1/VREF
AN2
C1IN+
C1IN-
—
—
—
—
—
IOC
IOC
Y
Y
Y
ICSPDAT/ULPWU
RA1
ICSPCLK
—
RA2
C1OUT
T0CKI
INT/IOC
RA3(1)
4
3
—
AN3
—
—
—
—
T1G
T1CKI
—
—
—
IOC
IOC
IOC
—
Y(2)
Y
MCLR/VPP
RA4
RA5
RC0
RC1
RC2
RC3
RC4
RC5
—
OSC2/CLKOUT
2
—
—
Y
OSC1/CLKIN
10
9
AN4
AN5
AN6
AN7
—
C2IN+
C2IN-
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
8
—
P1D
P1C
P1B
CCP1/P1A
—
—
—
7
—
—
—
—
6
C2OUT
—
—
—
—
5
—
—
—
—
1
—
—
—
—
VDD
VSS
—
14
—
—
—
—
—
Note 1: Input only.
2: Only when pin is configured for external MCLR.
DS41202F-page 2
© 2007 Microchip Technology Inc.
PIC16F684
16-Pin Diagram (QFN)
RA5/T1CKI/OSC1/CLKIN
RA0/AN0/C1IN+/ICSPDAT/ULPWU
12
11
10
9
1
2
3
4
RA4/AN3/T1G/OSC2/CLKOUT
RA3/MCLR/VPP
RA1/AN1/C1IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RC0/AN4/C2IN+
PIC16F684
RC5/CCP1/P1A
TABLE 2:
QFN PIN SUMMARY
I/O
Pin
Analog
Comparators
Timers
CCP
Interrupts Pull-ups
Basic
RA0
12
11
10
AN0
AN1/VREF
AN2
C1IN+
C1IN-
—
—
—
—
—
IOC
IOC
Y
Y
Y
ICSPDAT/ULPWU
RA1
ICSPCLK
—
RA2
C1OUT
T0CKI
INT/IOC
RA3(1)
3
2
—
AN3
—
—
—
—
T1G
T1CKI
—
—
—
IOC
IOC
IOC
—
Y(2)
Y
MCLR/VPP
RA4
RA5
RC0
RC1
RC2
RC3
RC4
RC5
—
OSC2/CLKOUT
1
—
—
Y
OSC1/CLKIN
9
AN4
AN5
AN6
AN7
—
C2IN+
C2IN-
—
—
—
—
—
—
—
—
—
—
—
—
8
—
—
—
7
—
P1D
P1C
P1B
—
—
6
—
—
—
—
5
C2OUT
—
—
—
—
4
—
—
—
—
CCP1/P1A
—
—
16
13
—
—
—
—
—
VDD
VSS
—
—
—
—
Note 1: Input only.
2: Only when pin is configured for external MCLR.
© 2007 Microchip Technology Inc.
DS41202F-page 3
PIC16F684
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 5
2.0 Memory Organization................................................................................................................................................................... 7
3.0 Oscillator Module (With Fail-Safe Clock Monitor)....................................................................................................................... 19
4.0 I/O Ports ..................................................................................................................................................................................... 31
5.0 Timer0 Module ........................................................................................................................................................................... 43
6.0 Timer1 Module with Gate Control............................................................................................................................................... 47
7.0 Timer2 Module ........................................................................................................................................................................... 53
8.0 Comparator Module.................................................................................................................................................................... 55
9.0 Analog-to-Digital Converter (ADC) Module ................................................................................................................................ 65
10.0 Data EEPROM Memory ............................................................................................................................................................. 75
11.0 Enhanced Capture/Compare/PWM (With Auto-Shutdown and Dead Band) Module................................................................. 79
12.0 Special Features of the CPU...................................................................................................................................................... 97
13.0 Instruction Set Summary.......................................................................................................................................................... 115
14.0 Development Support............................................................................................................................................................... 125
15.0 Electrical Specifications............................................................................................................................................................ 129
16.0 DC and AC Characteristics Graphs and Tables....................................................................................................................... 151
17.0 Packaging Information.............................................................................................................................................................. 173
Appendix A: Data Sheet Revision History.......................................................................................................................................... 179
Appendix B: Migrating from other PIC® Devices ............................................................................................................................... 179
Index .................................................................................................................................................................................................. 181
The Microchip Web Site..................................................................................................................................................................... 187
Customer Change Notification Service .............................................................................................................................................. 187
Customer Support.............................................................................................................................................................................. 187
Reader Response .............................................................................................................................................................................. 188
Product Identification System............................................................................................................................................................. 189
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DS41202F-page 4
© 2007 Microchip Technology Inc.
PIC16F684
1.0
DEVICE OVERVIEW
The PIC16F684 is covered by this data sheet. It is
available in 14-pin PDIP, SOIC, TSSOP and 16-pin
QFN packages. Figure 1-1 shows a block diagram of
the PIC16F684 device. Table 1-1 shows the pinout
description.
FIGURE 1-1:
PIC16F684 BLOCK DIAGRAM
INT
Configuration
13
8
PORTA
Data Bus
Program Counter
Flash
2k X 14
RA0
RA1
RA2
RA3
RA4
RA5
Program
RAM
128 Bytes
File
Registers
Memory
8-Level Stack
(13-Bit)
Program
Bus
14
RAM Addr
9
Addr MUX
Instruction Reg
PORTC
Indirect
Addr
7
Direct Addr
8
RC0
RC1
RC2
RC3
RC4
RC5
FSR Reg
STATUS Reg
8
3
MUX
Power-up
Timer
Instruction
Decode &
Control
Oscillator
Start-up Timer
ALU
Power-on
Reset
8
Timing
Generation
Watchdog
Timer
OSC1/CLKIN
W Reg
Brown-out
Reset
OSC2/CLKOUT
Internal
Oscillator
Block
P1B P1C P1D
CCP1/P1A
T1G
VDD
VSS
MCLR
T1CKI
Timer0
Timer1
Timer2
ECCP
T0CKI
2 Analog Comparators
and Reference
EEDATA
256 Bytes
Data
Analog-To-Digital Converter
8
EEPROM
EEADDR
VREF
AN0 AN1 AN2 AN3
AN4 AN5 AN6 AN7 C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT
© 2007 Microchip Technology Inc.
DS41202F-page 5
PIC16F684
TABLE 1-1:
PIC16F684 PINOUT DESCRIPTION
Input
Type
Output
Type
Name
Function
Description
RA0/AN0/C1IN+/ICSPDAT/ULPWU
RA1/AN1/C1IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RA0
AN0
TTL
AN
AN
TTL
AN
TTL
AN
AN
AN
ST
CMOS PORTA I/O with prog. pull-up and interrupt-on-change
—
—
A/D Channel 0 input
C1IN+
ICSPDAT
ULPWU
RA1
Comparator 1 non-inverting input
CMOS Serial Programming Data I/O
Ultra Low-Power Wake-Up input
CMOS PORTA I/O with prog. pull-up and interrupt-on-change
—
AN1
—
—
—
—
A/D Channel 1 input
C1IN-
VREF
ICSPCLK
RA2
Comparator 1 inverting input
External Voltage Reference for A/D
Serial Programming Clock
ST
CMOS PORTA I/O with prog. pull-up and interrupt-on-change
AN2
AN
ST
—
—
—
A/D Channel 2 input
Timer0 clock input
External Interrupt
T0CKI
INT
ST
C1OUT
RA3
—
CMOS Comparator 1 output
RA3/MCLR/VPP
TTL
ST
—
—
—
PORTA input with interrupt-on-change
MCLR
VPP
Master Clear w/internal pull-up
Programming voltage
HV
TTL
AN
ST
RA4/AN3/T1G/OSC2/CLKOUT
RA4
CMOS PORTA I/O with prog. pull-up and interrupt-on-change
AN3
—
—
A/D Channel 3 input
T1G
Timer1 gate (count enable)
OSC2
CLKOUT
RA5
—
XTAL Crystal/Resonator
—
CMOS FOSC/4 output
RA5/T1CKI/OSC1/CLKIN
TTL
ST
CMOS PORTA I/O with prog. pull-up and interrupt-on-change
T1CKI
OSC1
CLKIN
RC0
—
—
—
Timer1 clock
XTAL
ST
Crystal/Resonator
External clock input/RC oscillator connection
RC0/AN4/C2IN+
RC1/AN5/C2IN-
RC2/AN6/P1D
RC3/AN7/P1C
RC4/C2OUT/P1B
RC5/CCP1/P1A
TTL
AN
AN
TTL
AN
AN
TTL
AN
—
CMOS PORTC I/O
AN4
—
—
A/D Channel 4 input
Comparator 2 non-inverting input
C2IN+
RC1
CMOS PORTC I/O
AN5
—
—
A/D Channel 5 input
Comparator 2 inverting input
C2IN-
RC2
CMOS PORTC I/O
AN6
—
A/D Channel 6 input
P1D
CMOS PWM output
CMOS PORTC I/O
RC3
TTL
AN
—
AN7
—
A/D Channel 7 input
P1C
CMOS PWM output
CMOS PORTC I/O
CMOS Comparator 2 output
CMOS PWM output
CMOS PORTC I/O
CMOS Capture input/Compare output
CMOS PWM output
RC4
TTL
—
C2OUT
P1B
—
RC5
TTL
ST
CCP1
P1A
—
VDD
VDD
Power
Power
—
—
Positive supply
VSS
VSS
Ground reference
Legend: AN = Analog input or output
CMOS= CMOS compatible input or output HV = High Voltage
ST = Schmitt Trigger input with CMOS levels TTL = TTL compatible input
XTAL = Crystal
DS41202F-page 6
© 2007 Microchip Technology Inc.
PIC16F684
2.2
Data Memory Organization
2.0
2.1
MEMORY ORGANIZATION
Program Memory Organization
The data memory (see Figure 2-2) is partitioned into two
banks, which contain the General Purpose Registers
(GPR) and the Special Function Registers (SFR). The
Special Function Registers are located in the first 32
locations of each bank. Register locations 20h-7Fh in
Bank 0 and A0h-BFh in Bank 1 are General Purpose
Registers, implemented as static RAM. Register
locations F0h-FFh in Bank 1 point to addresses 70h-7Fh
in Bank 0. All other RAM is unimplemented and returns
‘0’ when read. The RP0 bit of the STATUS register is the
bank select bit.
The PIC16F684 has a 13-bit program counter capable
of addressing an 8k x 14 program memory space. Only
the first 2k x 14 (0000h-07FFh) for the PIC16F684 is
physically implemented. Accessing a location above
these boundaries will cause a wrap around within the
first 2k x 14 space. The Reset vector is at 0000h and
the interrupt vector is at 0004h (see Figure 2-1).
FIGURE 2-1:
PROGRAM MEMORY MAP
AND STACK FOR THE
PIC16F684
RP0
0
1
→
→
Bank 0 is selected
Bank 1 is selected
PC<12:0>
13
CALL, RETURN
RETFIE, RETLW
Note:
The IRP and RP1 bits of the STATUS
register are reserved and should always be
maintained as ‘0’s.
Stack Level 1
Stack Level 2
Stack Level 8
Reset Vector
0000h
Interrupt Vector
0004h
0005h
On-chip Program
Memory
07FFh
0800h
Wraps to 0000h-07FFh
1FFFh
© 2007 Microchip Technology Inc.
DS41202F-page 7
PIC16F684
2.2.1
GENERAL PURPOSE REGISTER
FILE
FIGURE 2-2:
DATA MEMORY MAP OF
THE PIC16F684
The register file is organized as 128 x 8 in the
PIC16F684. Each register is accessed, either directly
or indirectly, through the File Select Register (FSR)
(see Section 2.4 “Indirect Addressing, INDF and
FSR Registers”).
File
Address
File
Address
Indirect Addr.(1)
Indirect Addr.(1)
OPTION_REG
PCL
00h
01h
02h
80h
81h
82h
TMR0
PCL
STATUS
FSR
STATUS
FSR
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
0Dh
0Eh
0Fh
10h
11h
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
1Bh
1Ch
1Dh
1Eh
1Fh
20h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
8Dh
8Eh
8Fh
90h
91h
92h
93h
94h
95h
96h
97h
98h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
2.2.2
SPECIAL FUNCTION REGISTERS
The Special Function Registers are registers used by
the CPU and peripheral functions for controlling the
desired operation of the device (see Table 2-1). These
registers are static RAM.
PORTA
TRISA
PORTC
TRISC
The special registers can be classified into two sets:
core and peripheral. The Special Function Registers
associated with the “core” are described in this section.
Those related to the operation of the peripheral features
are described in the section of that peripheral feature.
PCLATH
INTCON
PIR1
PCLATH
INTCON
PIE1
TMR1L
TMR1H
PCON
OSCCON
OSCTUNE
ANSEL
T1CON
TMR2
T2CON
PR2
CCPR1L
CCPR1H
CCP1CON
PWM1CON
ECCPAS
WDTCON
CMCON0
CMCON1
WPUA
IOCA
VRCON
EEDAT
EEADR
EECON1
EECON2(1)
ADRESL
ADRESH
ADCON0
ADCON1
General
9Fh
A0h
Purpose
Registers
32 Bytes
BFh
General
Purpose
Registers
96 Bytes
6Fh
70
F0h
FFh
Accesses 70h-7Fh
Bank 1
7Fh
Bank 0
Unimplemented data memory locations, read as ‘0’.
Note 1: Not a physical register.
DS41202F-page 8
© 2007 Microchip Technology Inc.
PIC16F684
TABLE 2-1:
PIC16F684 SPECIAL FUNCTION REGISTERS SUMMARY BANK 0
Value on
POR, BOR
Addr
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
Bank 0
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
0Dh
0Eh
0Fh
10h
11h
INDF
Addressing this location uses contents of FSR to address data memory (not a physical register)
Timer0 Module’s Register
xxxx xxxx 19, 104
xxxx xxxx 43, 104
0000 0000 19, 104
0001 1xxx 13, 104
xxxx xxxx 19, 104
--x0 x000 31, 104
TMR0
PCL
Program Counter’s (PC) Least Significant Byte
STATUS
IRP(1)
RP1(1)
RP0
TO
PD
Z
DC
RA1
RC1
C
FSR
Indirect Data Memory Address Pointer
PORTA(2)
—
PORTC(2)
—
—
—
RA5
RC5
RA4
RC4
RA3
RC3
RA2
RC2
RA0
RC0
Unimplemented
—
—
—
--xx 0000 40, 104
—
Unimplemented
Unimplemented
—
—
—
—
—
—
PCLATH
INTCON
PIR1
—
—
Write Buffer for upper 5 bits of Program Counter
---0 0000 19, 104
0000 0000 15, 104
GIE
PEIE
ADIF
T0IE
INTE
C2IF
RAIE
C1IF
T0IF
INTF
RAIF
EEIF
CCP1IF
OSFIF
TMR2IF
TMR1IF 0000 0000 17, 104
—
Unimplemented
—
—
TMR1L
TMR1H
T1CON
TMR2
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 47, 104
xxxx xxxx 47, 104
T1GINV
TMR1GE T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
TMR1CS TMR1ON 0000 0000 50, 104
Timer2 Module Register
0000 0000 53, 104
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
1Bh
1Ch
1Dh
1Eh
1Fh
T2CON
CCPR1L
CCPR1H
CCP1CON
PWM1CON
ECCPAS
WDTCON
CMCON0
CMCON1
—
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 54, 104
Capture/Compare/PWM Register 1 Low Byte
Capture/Compare/PWM Register 1 High Byte
XXXX XXXX 80, 104
XXXX XXXX 80, 104
P1M1
P1M0
PDC6
DC1B1
PDC5
DC1B0
PDC4
CCP1M3
PDC3
CCP1M2
PDC2
CCP1M1
PDC1
CCP1M0 0000 0000 79, 104
PRSEN
PDC0
0000 0000 96, 104
ECCPASE ECCPAS2 ECCPAS1 ECCPAS0 PSSAC1
PSSAC0
WDTPS1
CM2
PSSBD1
PSSBD0 0000 0000 93, 104
WDTPS3
C1INV
—
WDTPS2
CIS
WDTPS0 SWDTEN ---0 1000 111, 104
—
C2OUT
—
—
C1OUT
—
—
C2INV
—
CM1
CM0
0000 0000 61, 104
—
—
T1GSS
C2SYNC ---- --10 62, 104
Unimplemented
Unimplemented
Unimplemented
—
—
—
—
—
—
—
—
ADRESH
ADCON0
Most Significant 8 bits of the left shifted A/D result or 2 bits of right shifted result
ADFM VCFG CHS2 CHS1 CHS0 GO/DONE
xxxx xxxx 71, 104
00-0 0000 70, 104
—
ADON
Legend:
Note 1:
2:
– = Unimplemented locations read as ‘0’, u= unchanged, x= unknown, q= value depends on condition, shaded = unimplemented
IRP and RP1 bits are reserved, always maintain these bits clear.
Port pins with analog functions controlled by the ANSEL register will read ‘0’ immediately after a Reset even though the data latches are
either undefined (POR) or unchanged (other Resets).
© 2007 Microchip Technology Inc.
DS41202F-page 9
PIC16F684
TABLE 2-2:
PIC16F684 SPECIAL FUNCTION REGISTERS SUMMARY BANK 1
Value on
POR, BOR
Addr
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
Bank 1
80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
8Dh
8Eh
8Fh
90h
91h
92h
93h
94h
95h
96h
97h
98h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
9Fh
INDF
Addressing this location uses contents of FSR to address data memory (not a physical register)
xxxx xxxx 19, 104
1111 1111 14, 104
0000 0000 19, 104
0001 1xxx 13, 104
xxxx xxxx 19, 104
--11 1111 31, 104
OPTION_REG
PCL
RAPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
Program Counter’s (PC) Least Significant Byte
STATUS
FSR
IRP(1)
RP1(1)
RP0
TO
PD
Z
DC
C
Indirect Data Memory Address Pointer
TRISA
—
—
—
—
TRISA5
TRISC5
TRISA4
TRISC4
TRISA3
TRISC3
TRISA2
TRISC2
TRISA1
TRISC1
TRISA0
TRISC0
Unimplemented
—
—
—
TRISC
—
--11 1111 40, 104
Unimplemented
Unimplemented
—
—
—
—
—
—
PCLATH
INTCON
PIE1
—
—
Write Buffer for upper 5 bits of Program Counter
---0 0000 19, 104
0000 0000 15, 104
GIE
PEIE
ADIE
T0IE
INTE
C2IE
RAIE
C1IE
T0IF
INTF
RAIF
EEIE
CCP1IE
OSFIE
TMR2IE
TMR1IE 0000 0000 16, 104
—
Unimplemented
—
—
—
PCON
OSCCON
OSCTUNE
ANSEL
PR2
—
ULPWUE SBOREN
—
—
POR
LTS
BOR
SCS
--01 --qq 18, 104
-110 x000 20, 104
---0 0000 24, 105
1111 1111 32, 105
1111 1111 53, 105
—
—
IRCF2
—
IRCF1
—
IRCF0
TUN4
ANS4
OSTS(2)
TUN3
ANS3
HTS
TUN2
ANS2
TUN1
ANS1
TUN0
ANS0
ANS7
ANS6
ANS5
Timer2 Module Period Register
Unimplemented
—
—
—
—
—
—
Unimplemented
WPUA(3)
—
—
—
WPUA5
IOCA5
WPUA4
IOCA4
—
WPUA2
IOCA2
WPUA1
IOCA1
WPUA0
IOCA0
--11 -111 33, 105
--00 0000 33, 105
IOCA
—
IOCA3
—
Unimplemented
Unimplemented
VREN
—
—
—
—
—
VRCON
EEDAT
EEADR
EECON1
EECON2
ADRESL
ADCON1
—
VRR
—
VR3
VR2
VR1
EEDAT1
EEADR1
WR
VR0
0-0- 0000 63, 105
EEDAT7
EEADR7
—
EEDAT6
EEADR6
—
EEDAT5
EEDAT4
EEDAT3
EEDAT2
EEADR2
WREN
EEDAT0 0000 0000 75, 105
EEADR0 0000 0000 75, 105
EEADR5 EEADR4 EEADR3
WRERR
—
—
RD
---- x000 76, 105
---- ---- 76, 105
xxxx xxxx 71, 105
-000 ---- 70, 105
EEPROM Control Register 2 (not a physical register)
Least Significant 2 bits of the left shifted result or 8 bits of the right shifted result
ADCS2 ADCS1 ADCS0 —
—
—
—
—
Legend:
Note 1:
– = Unimplemented locations read as ‘0’, u= unchanged, x= unknown, q= value depends on condition, shaded = unimplemented
IRP and RP1 bits are reserved, always maintain these bits clear.
2:
3:
OSTS bit of the OSCCON register reset to ‘0’ with Dual Speed Start-up and LP, HS or XT selected as the oscillator.
RA3 pull-up is enabled when MCLRE is ‘1’ in the Configuration Word register.
DS41202F-page 10
© 2007 Microchip Technology Inc.
PIC16F684
It is recommended, therefore, that only BCF, BSF,
SWAPF and MOVWF instructions are used to alter the
STATUS register, because these instructions do not
affect any Status bits. For other instructions not affect-
ing any Status bits, see Section 13.0 “Instruction Set
Summary”.
2.2.2.1
STATUS Register
The STATUS register, shown in Register 2-1, contains:
• the arithmetic status of the ALU
• the Reset status
• the bank select bits for data memory (SRAM)
The STATUS register can be the destination for any
instruction, like any other register. If the STATUS
register is the destination for an instruction that affects
the Z, DC or C bits, then the write to these three bits is
disabled. These bits are set or cleared according to the
device logic. Furthermore, the TO and PD bits are not
writable. Therefore, the result of an instruction with the
STATUS register as destination may be different than
intended.
Note 1: Bits IRP and RP1 of the STATUS register
are not used by the PIC16F684 and
should be maintained as clear. Use of
these bits is not recommended, since this
may affect upward compatibility with
future products.
2: The C and DC bits operate as a Borrow
and Digit Borrow out bit, respectively, in
subtraction. See the SUBLW and SUBWF
instructions for examples.
For example, CLRF STATUS,will clear the upper three
bits and set the Z bit. This leaves the STATUS register
as ‘000u u1uu’(where u= unchanged).
REGISTER 2-1:
STATUS: STATUS REGISTER
Reserved
IRP
Reserved
RP1
R/W-0
RP0
R-1
TO
R-1
PD
R/W-x
Z
R/W-x
DC
R/W-x
C
bit 7
bit 0
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
bit 7
bit 6
bit 5
IRP: This bit is reserved and should be maintained as ‘0’
RP1: This bit is reserved and should be maintained as ‘0’
RP0: Register Bank Select bit (used for direct addressing)
1= Bank 1 (80h – FFh)
0= Bank 0 (00h – 7Fh)
bit 4
bit 3
bit 2
bit 1
TO: Time-out bit
1= After power-up, CLRWDTinstruction or SLEEPinstruction
0= A WDT time-out occurred
PD: Power-down bit
1= After power-up or by the CLRWDTinstruction
0= By execution of the SLEEPinstruction
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 (ADDWF, ADDLW,SUBLW,SUBWFinstructions), For Borrow, the polarity is
reversed.
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
bit 0
C: Carry/Borrow bit(1) (ADDWF, ADDLW, SUBLW, SUBWF instructions)
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 1: For Borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the sec-
ond operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high-order or low-order bit
of the source register.
© 2007 Microchip Technology Inc.
DS41202F-page 11
PIC16F684
2.2.2.2
OPTION Register
Note:
To achieve a 1:1 prescaler assignment for
Timer0, assign the prescaler to the WDT
by setting PSA bit to ‘1’ of the OPTION
register. See Section 5.1.3 “Software
Programmable Prescaler”.
The OPTION register is a readable and writable register,
which contains various control bits to configure:
• Timer0/WDT prescaler
• External RA2/INT interrupt
• Timer0
• Weak pull-ups on PORTA
REGISTER 2-2:
OPTION_REG: OPTION REGISTER
R/W-1
RAPU
R/W-1
R/W-1
T0CS
R/W-1
T0SE
R/W-1
PSA
R/W-1
PS2
R/W-1
PS1
R/W-1
PS0
INTEDG
bit 7
bit 0
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
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
RAPU: PORTA Pull-up Enable bit
1= PORTA pull-ups are disabled
0= PORTA pull-ups are enabled by individual PORT latch values
INTEDG: Interrupt Edge Select bit
1= Interrupt on rising edge of RA2/INT pin
0= Interrupt on falling edge of RA2/INT pin
T0CS: Timer0 Clock Source Select bit
1= Transition on RA2/T0CKI pin
0= Internal instruction cycle clock (FOSC/4)
T0SE: Timer0 Source Edge Select bit
1= Increment on high-to-low transition on RA2/T0CKI pin
0= Increment on low-to-high transition on RA2/T0CKI pin
PSA: Prescaler Assignment bit
1= Prescaler is assigned to the WDT
0= Prescaler is assigned to the Timer0 module
PS<2:0>: Prescaler Rate Select bits
BIT VALUE TIMER0 RATE WDT RATE
000
001
010
011
100
101
110
111
1 : 2
1 : 1
1 : 4
1 : 2
1 : 8
1 : 4
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
DS41202F-page 12
© 2007 Microchip Technology Inc.
PIC16F684
2.2.2.3
INTCON Register
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, GIE of the INTCON register.
User software should ensure the
appropriate interrupt flag bits are clear
prior to enabling an interrupt.
The INTCON register is a readable and writable
register, which contains the various enable and flag bits
for TMR0 register overflow, PORTA change and
external RA2/INT pin interrupts.
REGISTER 2-3:
INTCON: INTERRUPT CONTROL REGISTER
R/W-0
GIE
R/W-0
PEIE
R/W-0
T0IE
R/W-0
INTE
R/W-0
RAIE
R/W-0
T0IF
R/W-0
INTF
R/W-0
RAIF
bit 7
bit 0
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
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
GIE: Global Interrupt Enable bit
1= Enables all unmasked interrupts
0= Disables all interrupts
PEIE: Peripheral Interrupt Enable bit
1= Enables all unmasked peripheral interrupts
0= Disables all peripheral interrupts
T0IE: Timer0 Overflow Interrupt Enable bit
1= Enables the Timer0 interrupt
0= Disables the Timer0 interrupt
INTE: RA2/INT External Interrupt Enable bit
1= Enables the RA2/INT external interrupt
0= Disables the RA2/INT external interrupt
RAIE: PORTA Change Interrupt Enable bit(1)
1= Enables the PORTA change interrupt
0= Disables the PORTA change interrupt
T0IF: Timer0 Overflow Interrupt Flag bit(2)
1= Timer0 register has overflowed (must be cleared in software)
0= Timer0 register did not overflow
INTF: RA2/INT External Interrupt Flag bit
1= The RA2/INT external interrupt occurred (must be cleared in software)
0= The RA2/INT external interrupt did not occur
RAIF: PORTA Change Interrupt Flag bit
1= When at least one of the PORTA <5:0> pins changed state (must be cleared in software)
0= None of the PORTA <5:0> pins have changed state
Note 1: IOCA register must also be enabled.
2: T0IF bit is set when TMR0 rolls over. TMR0 is unchanged on Reset and should be initialized before
clearing T0IF bit.
© 2007 Microchip Technology Inc.
DS41202F-page 13
PIC16F684
2.2.2.4
PIE1 Register
The PIE1 register contains the peripheral interrupt
enable bits, as shown in Register 2-4.
Note:
Bit PEIE of the INTCON register must be
set to enable any peripheral interrupt.
REGISTER 2-4:
PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
R/W-0
EEIE
R/W-0
ADIE
R/W-0
R/W-0
C2IE
R/W-0
C1IE
R/W-0
OSFIE
R/W-0
R/W-0
CCP1IE
TMR2IE
TMR1IE
bit 7
bit 0
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
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
EEIE: EE Write Complete Interrupt Enable bit
1= Enables the EE write complete interrupt
0= Disables the EE write complete interrupt
ADIE: A/D Converter (ADC) Interrupt Enable bit
1= Enables the ADC interrupt
0= Disables the ADC interrupt
CCP1IE: CCP1 Interrupt Enable bit
1= Enables the CCP1 interrupt
0= Disables the CCP1 interrupt
C2IE: Comparator 2 Interrupt Enable bit
1= Enables the Comparator 2 interrupt
0= Disables the Comparator 2 interrupt
C1IE: Comparator 1 Interrupt Enable bit
1= Enables the Comparator 1 interrupt
0= Disables the Comparator 1 interrupt
OSFIE: Oscillator Fail Interrupt Enable bit
1= Enables the oscillator fail interrupt
0= Disables the oscillator fail interrupt
TMR2IE: Timer2 to PR2 Match Interrupt Enable bit
1= Enables the Timer2 to PR2 match interrupt
0= Disables the Timer2 to PR2 match interrupt
TMR1IE: Timer1 Overflow Interrupt Enable bit
1= Enables the Timer1 overflow interrupt
0= Disables the Timer1 overflow interrupt
DS41202F-page 14
© 2007 Microchip Technology Inc.
PIC16F684
2.2.2.5
PIR1 Register
The PIR1 register contains the peripheral interrupt flag
bits, as shown in Register 2-5.
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, GIE of the INTCON register. User
software should ensure the appropriate
interrupt flag bits are clear prior to enabling
an interrupt.
REGISTER 2-5:
PIR1: PERIPHERAL INTERRUPT REQUEST REGISTER 1
R/W-0
EEIF
R/W-0
ADIF
R/W-0
R/W-0
C2IF
R/W-0
C1IF
R/W-0
OSFIF
R/W-0
R/W-0
CCP1IF
TMR2IF
TMR1IF
bit 7
bit 0
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
bit 7
bit 6
bit 5
EEIF: EEPROM Write Operation Interrupt Flag bit
1= The write operation completed (must be cleared in software)
0= The write operation has not completed or has not been started
ADIF: A/D Interrupt Flag bit
1= A/D conversion complete
0= A/D conversion has not completed or has not been started
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 4
bit 3
bit 2
bit 1
bit 0
C2IF: Comparator 2 Interrupt Flag bit
1= Comparator 2 output has changed (must be cleared in software)
0= Comparator 2 output has not changed
C1IF: Comparator 1 Interrupt Flag bit
1= Comparator 1 output has changed (must be cleared in software)
0= Comparator 1 output has not changed
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
TMR2IF: Timer2 to PR2 Match Interrupt Flag bit
1= Timer2 to PR2 match occurred (must be cleared in software)
0= Timer2 to PR2 match has not occurred
TMR1IF: Timer1 Overflow Interrupt Flag bit
1= Timer1 register overflowed (must be cleared in software)
0= Timer1 has not overflowed
© 2007 Microchip Technology Inc.
DS41202F-page 15
PIC16F684
2.2.2.6
PCON Register
The Power Control (PCON) register (see Table 12-2)
contains flag bits to differentiate between a:
• Power-on Reset (POR)
• Brown-out Reset (BOR)
• Watchdog Timer Reset (WDT)
• External MCLR Reset
The PCON register also controls the Ultra Low-Power
Wake-up and software enable of the BOR.
The PCON register bits are shown in Register 2-6.
REGISTER 2-6:
PCON: POWER CONTROL REGISTER
U-0
—
U-0
—
R/W-0
R/W-1
U-0
—
U-0
—
R/W-0
POR
R/W-x
BOR
ULPWUE
SBOREN
bit 7
bit 0
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
bit 7-6
bit 5
Unimplemented: Read as ‘0’
ULPWUE: Ultra Low-Power Wake-Up Enable bit
1= Ultra Low-Power Wake-up enabled
0= Ultra Low-Power Wake-up disabled
bit 4
SBOREN: Software BOR Enable bit(1)
1= BOR enabled
0= BOR disabled
bit 3-2
bit 1
Unimplemented: Read as ‘0’
POR: Power-on Reset Status bit
1= No Power-on Reset occurred
0= A Power-on Reset occurred (must be set in software after a Power-on Reset occurs)
bit 0
BOR: Brown-out Reset Status bit
1= No Brown-out Reset occurred
0= A Brown-out Reset occurred (must be set in software after a Power-on Reset or Brown-out Reset
occurs)
Note 1: BOREN<1:0> = 01in the Configuration Word register for this bit to control the BOR.
DS41202F-page 16
© 2007 Microchip Technology Inc.
PIC16F684
2.3.2
STACK
2.3
PCL and PCLATH
The PIC16F684 Family has an 8-level x 13-bit wide
hardware stack (see Figure 2-1). The stack space is
not part of either program or data space and the Stack
Pointer is not readable or writable. The PC is PUSHed
onto the stack when a CALLinstruction is executed or
an interrupt causes a branch. The stack is POPed in
The Program Counter (PC) is 13 bits wide. The low byte
comes from the PCL register, which is a readable and
writable register. The high byte (PC<12:8>) is not directly
readable or writable and comes from PCLATH. On any
Reset, the PC is cleared. Figure 2-3 shows the two
situations for the loading of the PC. The upper example
in Figure 2-3 shows how the PC is loaded on a write to
PCL (PCLATH<4:0> → PCH). The lower example in
Figure 2-3 shows how the PC is loaded during a CALLor
GOTOinstruction (PCLATH<4:3> → PCH).
the event of a RETURN,
RETLW or a RETFIE
instruction execution. PCLATH is not affected by a
PUSH or POP operation.
The stack operates as a circular buffer. This means that
after the stack has been PUSHed eight times, the ninth
push overwrites the value that was stored from the first
push. The tenth push overwrites the second push (and
so on).
FIGURE 2-3:
LOADING OF PC IN
DIFFERENT SITUATIONS
PCH
PCL
Instruction with
Note 1: There are no Status bits to indicate stack
12
8
7
0
PCL as
overflow or stack underflow conditions.
Destination
PC
2: There are no instructions/mnemonics
called PUSH or POP. These are actions
that occur from the execution of the
CALL, RETURN, RETLW and RETFIE
instructions or the vectoring to an
interrupt address.
8
PCLATH<4:0>
PCLATH
5
ALU Result
PCH
12 11 10
PC
PCL
8
7
0
GOTO, CALL
2.4
Indirect Addressing, INDF and
FSR Registers
PCLATH<4:3>
PCLATH
11
2
OPCODE <10:0>
The INDF register is not a physical register. Addressing
the INDF register will cause indirect addressing.
Indirect addressing is possible by using the INDF register.
Any instruction using the INDF register actually accesses
data pointed to by the File Select Register (FSR).
Reading INDF itself indirectly will produce 00h. Writing to
the INDF register indirectly results in a no operation
(although Status bits may be affected). An effective 9-bit
address is obtained by concatenating the 8-bit FSR and
the IRP bit of the STATUS register, as shown in
Figure 2-4.
2.3.1
MODIFYING PCL
Executing any instruction with the PCL register as the
destination simultaneously causes the Program
Counter PC<12:8> bits (PCH) to be replaced by the
contents of the PCLATH register. This allows the entire
contents of the program counter to be changed by first
writing the desired upper 5 bits to the PCLATH register.
Then, when the lower 8 bits are written to the PCL
register, all 13 bits of the program counter will change
to the values contained in the PCLATH register and
those being written to the PCL register.
A simple program to clear RAM location 20h-2Fh using
indirect addressing is shown in Example 2-1.
EXAMPLE 2-1:
INDIRECT ADDRESSING
A computed GOTOis accomplished by adding an offset
to the program counter (ADDWF PCL). Care should be
exercised when jumping into a look-up table or
program branch table (computed GOTO) by modifying
the PCL register. Assuming that PCLATH is set to the
table start address, if the table length is greater than
255 instructions or if the lower 8 bits of the memory
address rolls over from 0xFF to 0x00 in the middle of
the table, then PCLATH must be incremented for each
address rollover that occurs between the table
beginning and the target location within the table.
MOVLW
MOVWF
0x20
FSR
;initialize pointer
;to RAM
NEXT
CLRF
INCF
BTFSS
GOTO
INDF
;clear INDF register
FSR, f ;inc pointer
FSR,4
NEXT
;all done?
;no clear next
;yes continue
CONTINUE
For more information refer to Application Note AN556,
“Implementing a Table Read” (DS00556).
© 2007 Microchip Technology Inc.
DS41202F-page 17
PIC16F684
FIGURE 2-4:
DIRECT/INDIRECT ADDRESSING PIC16F684
Direct Addressing
From Opcode
Indirect Addressing
(1)
(1)
7
RP1
RP0
6
0
0
IRP
File Select Register
Bank Select
180h
Location Select
Bank Select
Location Select
00h
00
01
10
11
Data
Memory
NOT USED
7Fh
1FFh
Bank 0
Bank 1
Bank 2
Bank 3
For memory map detail, see Figure 2-2.
Note 1: The RP1 and IRP bits are reserved; always maintain these bits clear.
DS41202F-page 18
© 2007 Microchip Technology Inc.
PIC16F684
The Oscillator module can be configured in one of eight
clock modes.
3.0
3.1
OSCILLATOR MODULE (WITH
FAIL-SAFE CLOCK MONITOR)
1. EC – External clock with I/O on OSC2/CLKOUT.
2. LP – 32 kHz Low-Power Crystal mode.
Overview
3. XT – Medium Gain Crystal or Ceramic Resonator
Oscillator mode.
The Oscillator module has a wide variety of clock
sources and selection features that allow it to be used
in a wide range of applications while maximizing perfor-
mance and minimizing power consumption. Figure 3-1
illustrates a block diagram of the Oscillator module.
4. HS – High Gain Crystal or Ceramic Resonator
mode.
5. RC – External Resistor-Capacitor (RC) with
FOSC/4 output on OSC2/CLKOUT.
Clock sources can be configured from external
oscillators, quartz crystal resonators, ceramic resonators
and Resistor-Capacitor (RC) circuits. In addition, the
system clock source can be configured from one of two
internal oscillators, with a choice of speeds selectable via
software. Additional clock features include:
6. RCIO – External Resistor-Capacitor (RC) with
I/O on OSC2/CLKOUT.
7. INTOSC – Internal oscillator with FOSC/4 output
on OSC2 and I/O on OSC1/CLKIN.
8. INTOSCIO – Internal oscillator with I/O on
OSC1/CLKIN and OSC2/CLKOUT.
• Selectable system clock source between external
or internal via software.
Clock Source modes are configured by the FOSC<2:0>
bits in the Configuration Word register (CONFIG). The
internal clock can be generated from two internal
• Two-Speed Start-up mode, which minimizes
latency between external oscillator start-up and
code execution.
oscillators. The HFINTOSC is
a
calibrated
high-frequency oscillator. The LFINTOSC is an
uncalibrated low-frequency oscillator.
• Fail-Safe Clock Monitor (FSCM) designed to
detect a failure of the external clock source (LP,
XT, HS, EC or RC modes) and switch
automatically to the internal oscillator.
FIGURE 3-1:
PIC® MCU CLOCK SOURCE BLOCK DIAGRAM
FOSC<2:0>
(Configuration Word Register)
External Oscillator
SCS<0>
(OSCCON Register)
OSC2
OSC1
Sleep
LP, XT, HS, RC, RCIO, EC
IRCF<2:0>
(OSCCON Register)
System Clock
(CPU and Peripherals)
8 MHz
111
110
101
INTOSC
Internal Oscillator
4 MHz
2 MHz
1 MHz
HFINTOSC
8 MHz
100
011
010
001
000
500 kHz
250 kHz
125 kHz
31 kHz
LFINTOSC
31 kHz
Power-up Timer (PWRT)
Watchdog Timer (WDT)
Fail-Safe Clock Monitor (FSCM)
© 2007 Microchip Technology Inc.
DS41202F-page 19
PIC16F684
3.2
Oscillator Control
The Oscillator Control (OSCCON) register (Figure 3-1)
controls the system clock and frequency selection
options. The OSCCON register contains the following
bits:
• Frequency selection bits (IRCF)
• Frequency Status bits (HTS, LTS)
• System clock control bits (OSTS, SCS)
REGISTER 3-1:
OSCCON: OSCILLATOR CONTROL REGISTER
U-0
—
R/W-1
IRCF2
R/W-1
IRCF1
R/W-0
IRCF0
R-1
OSTS(1)
R-0
R-0
LTS
R/W-0
SCS
HTS
bit 7
bit 0
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
bit 7
Unimplemented: Read as ‘0’
bit 6-4
IRCF<2:0>: Internal Oscillator Frequency Select bits
111=8 MHz
110=4 MHz (default)
101=2 MHz
100=1 MHz
011=500 kHz
010=250 kHz
001=125 kHz
000=31 kHz (LFINTOSC)
bit 3
bit 2
bit 1
bit 0
OSTS: Oscillator Start-up Time-out Status bit(1)
1= Device is running from the external clock defined by FOSC<2:0> of the CONFIG register
0= Device is running from the internal oscillator (HFINTOSC or LFINTOSC)
HTS: HFINTOSC Status bit (High Frequency – 8 MHz to 125 kHz)
1= HFINTOSC is stable
0= HFINTOSC is not stable
LTS: LFINTOSC Stable bit (Low Frequency – 31 kHz)
1= LFINTOSC is stable
0= LFINTOSC is not stable
SCS: System Clock Select bit
1= Internal oscillator is used for system clock
0= Clock source defined by FOSC<2:0> of the CONFIG register
Note 1: Bit resets to ‘0’ with Two-Speed Start-up and LP, XT or HS selected as the Oscillator mode or Fail-Safe
mode is enabled.
DS41202F-page 20
© 2007 Microchip Technology Inc.
PIC16F684
3.3
Clock Source Modes
3.4
External Clock Modes
Clock Source modes can be classified as external or
internal.
3.4.1 OSCILLATOR START-UP TIMER (OST)
If the Oscillator module is configured for LP, XT or HS
modes, the Oscillator Start-up Timer (OST) counts
1024 oscillations from OSC1. This occurs following a
Power-on Reset (POR) and when the Power-up Timer
(PWRT) has expired (if configured), or a wake-up from
Sleep. During this time, the program counter does not
increment and program execution is suspended. The
OST ensures that the oscillator circuit, using a quartz
crystal resonator or ceramic resonator, has started and
is providing a stable system clock to the Oscillator
module. When switching between clock sources, a
delay is required to allow the new clock to stabilize.
These oscillator delays are shown in Table 3-1.
• External Clock modes rely on external circuitry for
the clock source. Examples are: Oscillator mod-
ules (EC mode), quartz crystal resonators or
ceramic resonators (LP, XT and HS modes) and
Resistor-Capacitor (RC) mode circuits.
• Internal clock sources are contained internally
within the Oscillator module. The Oscillator
module has two internal oscillators: the 8 MHz
High-Frequency Internal Oscillator (HFINTOSC)
and the 31 kHz Low-Frequency Internal Oscillator
(LFINTOSC).
The system clock can be selected between external or
internal clock sources via the System Clock Select
(SCS) bit of the OSCCON register. See Section 3.6
“Clock Switching” for additional information.
In order to minimize latency between external oscillator
start-up and code execution, the Two-Speed Clock
Start-up mode can be selected (see Section 3.7
“Two-Speed Clock Start-up Mode”).
TABLE 3-1:
Switch From
OSCILLATOR DELAY EXAMPLES
Switch To
Frequency
Oscillator Delay
LFINTOSC
HFINTOSC
31 kHz
125 kHz to 8 MHz
DC – 20 MHz
Sleep/POR
Oscillator Warm-Up Delay (TWARM)
Sleep/POR
EC, RC
2 cycles
LFINTOSC (31 kHz)
Sleep/POR
EC, RC
DC – 20 MHz
1 cycle of each
1024 Clock Cycles (OST)
1 μs (approx.)
LP, XT, HS
HFINTOSC
32 kHz to 20 MHz
125 kHz to 8 MHz
LFINTOSC (31 kHz)
3.4.2
EC MODE
FIGURE 3-2:
EXTERNAL CLOCK (EC)
MODE OPERATION
The External Clock (EC) mode allows an externally
generated logic level as the system clock source. When
operating in this mode, an external clock source is
connected to the OSC1 input and the OSC2 is available
for general purpose I/O. Figure 3-2 shows the pin
connections for EC mode.
OSC1/CLKIN
Clock from
Ext. System
PIC® MCU
(1)
I/O
OSC2/CLKOUT
The Oscillator Start-up Timer (OST) is disabled when
EC mode is selected. Therefore, there is no delay in
operation after a Power-on Reset (POR) or wake-up
from Sleep. Because the PIC MCU design is fully static,
stopping the external clock input will have the effect of
halting the device while leaving all data intact. Upon
restarting the external clock, the device will resume
operation as if no time had elapsed.
Note 1: Alternate pin functions are listed in the
Section 1.0 “Device Overview”.
© 2007 Microchip Technology Inc.
DS41202F-page 21
PIC16F684
3.4.3
LP, XT, HS MODES
Note 1: Quartz crystal characteristics vary according
to type, package and manufacturer. The
user should consult the manufacturer data
sheets for specifications and recommended
application.
The LP, XT and HS modes support the use of quartz
crystal resonators or ceramic resonators connected to
OSC1 and OSC2 (Figure 3-3). The mode selects a low,
medium or high gain setting of the internal
inverter-amplifier to support various resonator types
and speed.
2: Always verify oscillator performance over
the VDD and temperature range that is
expected for the application.
LP Oscillator mode selects the lowest gain setting of the
internal inverter-amplifier. LP mode current consumption
is the least of the three modes. This mode is designed to
drive only 32.768 kHz tuning-fork type crystals (watch
crystals).
3: For oscillator design assistance, reference
the following Microchip Applications Notes:
• AN826, “Crystal Oscillator Basics and
Crystal Selection for rfPIC® and PIC®
Devices” (DS00826)
• AN849, “Basic PIC® Oscillator Design”
(DS00849)
• AN943, “Practical PIC® Oscillator
XT Oscillator mode selects the intermediate gain
setting of the internal inverter-amplifier. XT mode
current consumption is the medium of the three modes.
This mode is best suited to drive resonators with a
medium drive level specification.
Analysis and Design” (DS00943)
HS Oscillator mode selects the highest gain setting of the
internal inverter-amplifier. HS mode current consumption
is the highest of the three modes. This mode is best
suited for resonators that require a high drive setting.
• AN949, “Making Your Oscillator Work”
(DS00949)
FIGURE 3-4:
CERAMIC RESONATOR
OPERATION
Figure 3-3 and Figure 3-4 show typical circuits for
quartz crystal and ceramic resonators, respectively.
(XT OR HS MODE)
FIGURE 3-3:
QUARTZ CRYSTAL
OPERATION (LP, XT OR
HS MODE)
PIC® MCU
OSC1/CLKIN
C1
PIC® MCU
To Internal
Logic
OSC1/CLKIN
(3)
(2)
RP
RF
Sleep
C1
To Internal
Logic
Quartz
Crystal
(2)
OSC2/CLKOUT
(1)
C2
RF
Sleep
RS
Ceramic
Resonator
Note 1: A series resistor (RS) may be required for
OSC2/CLKOUT
(1)
C2
RS
ceramic resonators with low drive level.
2: The value of RF varies with the Oscillator mode
selected (typically between 2 MΩ to 10 MΩ).
Note 1: A series resistor (RS) may be required for
quartz crystals with low drive level.
3: An additional parallel feedback resistor (RP)
may be required for proper ceramic resonator
operation.
2: The value of RF varies with the Oscillator mode
selected (typically between 2 MΩ to 10 MΩ).
DS41202F-page 22
© 2007 Microchip Technology Inc.
PIC16F684
3.4.4
EXTERNAL RC MODES
3.5
Internal Clock Modes
The external Resistor-Capacitor (RC) modes support
the use of an external RC circuit. This allows the
designer maximum flexibility in frequency choice while
keeping costs to a minimum when clock accuracy is not
required. There are two modes: RC and RCIO.
The Oscillator module has two independent, internal
oscillators that can be configured or selected as the
system clock source.
1. The HFINTOSC (High-Frequency Internal
Oscillator) is factory calibrated and operates at
8 MHz. The frequency of the HFINTOSC can be
user-adjusted via software using the OSCTUNE
register (Register 3-2).
In RC mode, the RC circuit connects to OSC1.
OSC2/CLKOUT outputs the RC oscillator frequency
divided by 4. This signal may be used to provide a clock
for external circuitry, synchronization, calibration, test
or other application requirements. Figure 3-5 shows
the external RC mode connections.
2. The LFINTOSC (Low-Frequency Internal
Oscillator) is uncalibrated and operates at
31 kHz.
The system clock speed can be selected via software
using the Internal Oscillator Frequency Select bits
IRCF<2:0> of the OSCCON register.
FIGURE 3-5:
EXTERNAL RC MODES
VDD
PIC® MCU
The system clock can be selected between external or
internal clock sources via the System Clock Selection
(SCS) bit of the OSCCON register. See Section 3.6
“Clock Switching” for more information.
REXT
OSC1/CLKIN
Internal
Clock
CEXT
VSS
3.5.1 INTOSC AND INTOSCIO MODES
The INTOSC and INTOSCIO modes configure the
internal oscillators as the system clock source when
the device is programmed using the oscillator selection
or the FOSC<2:0> bits in the Configuration Word
register (CONFIG).
(1)
FOSC/4 or
I/O
OSC2/CLKOUT
(2)
Recommended values: 10 kΩ ≤ REXT ≤ 100 kΩ, <3V
3 kΩ ≤ REXT ≤ 100 kΩ, 3-5V
In INTOSC mode, OSC1/CLKIN is available for general
purpose I/O. OSC2/CLKOUT outputs the selected
internal oscillator frequency divided by 4. The CLKOUT
signal may be used to provide a clock for external
circuitry, synchronization, calibration, test or other
application requirements.
CEXT > 20 pF, 2-5V
Note 1: Alternate pin functions are listed in
Section 1.0 “Device Overview”.
2: Output depends upon RC or RCIO Clock
mode.
In INTOSCIO mode, OSC1/CLKIN and OSC2/CLKOUT
In RCIO mode, the RC circuit is connected to OSC1.
OSC2 becomes an additional general purpose I/O pin.
are available for general purpose I/O.
3.5.2
HFINTOSC
The RC oscillator frequency is a function of the supply
voltage, the resistor (REXT) and capacitor (CEXT) values
and the operating temperature. Other factors affecting
the oscillator frequency are:
The High-Frequency Internal Oscillator (HFINTOSC) is
a factory calibrated 8 MHz internal clock source. The
frequency of the HFINTOSC can be altered via
software using the OSCTUNE register (Register 3-2).
• threshold voltage variation
• component tolerances
• packaging variations in capacitance
The output of the HFINTOSC connects to a postscaler
and multiplexer (see Figure 3-1). One of seven
frequencies can be selected via software using the
IRCF<2:0> bits of the OSCCON register. See
Section 3.5.4 “Frequency Select Bits (IRCF)” for
more information.
The user also needs to take into account variation due
to tolerance of external RC components used.
The HFINTOSC is enabled by selecting any frequency
between 8 MHz and 125 kHz by setting the IRCF<2:0>
bits of the OSCCON register ≠ 000. Then, set the
System Clock Source (SCS) bit of the OSCCON
register to ‘1’ or enable Two-Speed Start-up by setting
the IESO bit in the Configuration Word register
(CONFIG) to ‘1’.
The HF Internal Oscillator (HTS) bit of the OSCCON
register indicates whether the HFINTOSC is stable or not.
© 2007 Microchip Technology Inc.
DS41202F-page 23
PIC16F684
When the OSCTUNE register is modified, the
HFINTOSC frequency will begin shifting to the new
frequency. Code execution continues during this shift.
There is no indication that the shift has occurred.
3.5.2.1
OSCTUNE Register
The HFINTOSC is factory calibrated but can be
adjusted in software by writing to the OSCTUNE
register (Register 3-2).
OSCTUNE does not affect the LFINTOSC frequency.
Operation of features that depend on the LFINTOSC
clock source frequency, such as the Power-up Timer
(PWRT), Watchdog Timer (WDT), Fail-Safe Clock
Monitor (FSCM) and peripherals, are not affected by the
change in frequency.
The default value of the OSCTUNE register is ‘0’. The
value is a 5-bit two’s complement number.
REGISTER 3-2:
OSCTUNE: OSCILLATOR TUNING REGISTER
U-0
—
U-0
—
U-0
—
R/W-0
TUN4
R/W-0
TUN3
R/W-0
TUN2
R/W-0
TUN1
R/W-0
TUN0
bit 7
bit 0
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
bit 7-5
bit 4-0
Unimplemented: Read as ‘0’
TUN<4:0>: Frequency Tuning bits
01111= Maximum frequency
01110=
•
•
•
00001=
00000= Oscillator module is running at the calibrated frequency.
11111=
•
•
•
10000= Minimum frequency
DS41202F-page 24
© 2007 Microchip Technology Inc.
PIC16F684
3.5.3
LFINTOSC
3.5.5
HFINTOSC AND LFINTOSC CLOCK
SWITCH TIMING
The Low-Frequency Internal Oscillator (LFINTOSC) is
an uncalibrated 31 kHz internal clock source.
When switching between the LFINTOSC and the
HFINTOSC, the new oscillator may already be shut
down to save power (see Figure 3-6). If this is the case,
there is a delay after the IRCF<2:0> bits of the
OSCCON register are modified before the frequency
selection takes place. The LTS and HTS bits of the
OSCCON register will reflect the current active status
of the LFINTOSC and HFINTOSC oscillators. The
timing of a frequency selection is as follows:
The output of the LFINTOSC connects to a postscaler
and multiplexer (see Figure 3-1). Select 31 kHz, via
software, using the IRCF<2:0> bits of the OSCCON
register. See Section 3.5.4 “Frequency Select Bits
(IRCF)” for more information. The LFINTOSC is also the
frequency for the Power-up Timer (PWRT), Watchdog
Timer (WDT) and Fail-Safe Clock Monitor (FSCM).
The LFINTOSC is enabled by selecting 31 kHz
(IRCF<2:0> bits of the OSCCON register = 000)as the
system clock source (SCS bit of the OSCCON
register = 1), or when any of the following are enabled:
1. IRCF<2:0> bits of the OSCCON register are
modified.
2. If the new clock is shut down, a clock start-up
delay is started.
• Two-Speed Start-up IESO bit of the Configuration
Word register = 1and IRCF<2:0> bits of the
OSCCON register = 000
3. Clock switch circuitry waits for a falling edge of
the current clock.
4. CLKOUT is held low and the clock switch
circuitry waits for a rising edge in the new clock.
• Power-up Timer (PWRT)
• Watchdog Timer (WDT)
5. CLKOUT is now connected with the new clock.
LTS and HTS bits of the OSCCON register are
updated as required.
• Fail-Safe Clock Monitor (FSCM)
The LF Internal Oscillator (LTS) bit of the OSCCON
register indicates whether the LFINTOSC is stable or
not.
6. Clock switch is complete.
See Figure 3-1 for more details.
3.5.4
FREQUENCY SELECT BITS (IRCF)
If the internal oscillator speed selected is between
8 MHz and 125 kHz, there is no start-up delay before
the new frequency is selected. This is because the old
and new frequencies are derived from the HFINTOSC
via the postscaler and multiplexer.
The output of the 8 MHz HFINTOSC and 31 kHz
LFINTOSC connects to a postscaler and multiplexer
(see Figure 3-1). The Internal Oscillator Frequency
Select bits IRCF<2:0> of the OSCCON register select
the frequency output of the internal oscillators. One of
eight frequencies can be selected via software:
Start-up delay specifications are located in the
oscillator tables of Section 15.0 “Electrical
Specifications”.
• 8 MHz
• 4 MHz (Default after Reset)
• 2 MHz
• 1 MHz
• 500 kHz
• 250 kHz
• 125 kHz
• 31 kHz (LFINTOSC)
Note:
Following any Reset, the IRCF<2:0> bits of
the OSCCON register are set to ‘110’ and
the frequency selection is set to 4 MHz.
The user can modify the IRCF bits to
select a different frequency.
© 2007 Microchip Technology Inc.
DS41202F-page 25
PIC16F684
FIGURE 3-6:
INTERNAL OSCILLATOR SWITCH TIMING
HFINTOSC
LFINTOSC (FSCM and WDT disabled)
HFINTOSC
Start-up Time
2-cycle Sync
Running
LFINTOSC
≠ 0
= 0
IRCF <2:0>
System Clock
HFINTOSC
LFINTOSC (Either FSCM or WDT enabled)
HFINTOSC
2-cycle Sync
Running
LFINTOSC
IRCF <2:0>
≠ 0
= 0
System Clock
LFINTOSC
HFINTOSC
LFINTOSC turns off unless WDT or FSCM is enabled
Running
LFINTOSC
Start-up Time 2-cycle Sync
HFINTOSC
= 0
¼ 0
IRCF <2:0>
System Clock
DS41202F-page 26
© 2007 Microchip Technology Inc.
PIC16F684
When the Oscillator module is configured for LP, XT or
HS modes, the Oscillator Start-up Timer (OST) is
enabled (see Section 3.4.1 “Oscillator Start-up Timer
(OST)”). The OST will suspend program execution until
1024 oscillations are counted. Two-Speed Start-up
mode minimizes the delay in code execution by
operating from the internal oscillator as the OST is
counting. When the OST count reaches 1024 and the
OSTS bit of the OSCCON register is set, program
execution switches to the external oscillator.
3.6
Clock Switching
The system clock source can be switched between
external and internal clock sources via software using
the System Clock Select (SCS) bit of the OSCCON
register.
3.6.1
SYSTEM CLOCK SELECT (SCS) BIT
The System Clock Select (SCS) bit of the OSCCON
register selects the system clock source that is used for
the CPU and peripherals.
3.7.1
TWO-SPEED START-UP MODE
CONFIGURATION
• When the SCS bit of the OSCCON register = 0,
the system clock source is determined by
configuration of the FOSC<2:0> bits in the
Configuration Word register (CONFIG).
Two-Speed Start-up mode is configured by the
following settings:
• When the SCS bit of the OSCCON register = 1,
the system clock source is chosen by the internal
oscillator frequency selected by the IRCF<2:0>
bits of the OSCCON register. After a Reset, the
SCS bit of the OSCCON register is always
cleared.
• IESO (of the Configuration Word register) = 1;
Internal/External Switchover bit (Two-Speed
Start-up mode enabled).
• SCS (of the OSCCON register) = 0.
• FOSC<2:0> bits in the Configuration Word
register (CONFIG) configured for LP, XT or HS
mode.
Note:
Any automatic clock switch, which may
occur from Two-Speed Start-up or Fail-Safe
Clock Monitor, does not update the SCS bit
of the OSCCON register. The user can
monitor the OSTS bit of the OSCCON
register to determine the current system
clock source.
Two-Speed Start-up mode is entered after:
• Power-on Reset (POR) and, if enabled, after
Power-up Timer (PWRT) has expired, or
• Wake-up from Sleep.
If the external clock oscillator is configured to be
anything other than LP, XT or HS mode, then
Two-Speed Start-up is disabled. This is because the
external clock oscillator does not require any
stabilization time after POR or an exit from Sleep.
3.6.2
OSCILLATOR START-UP TIME-OUT
STATUS (OSTS) BIT
The Oscillator Start-up Time-out Status (OSTS) bit of
the OSCCON register indicates whether the system
clock is running from the external clock source, as
defined by the FOSC<2:0> bits in the Configuration
Word register (CONFIG), or from the internal clock
source. In particular, OSTS indicates that the Oscillator
Start-up Timer (OST) has timed out for LP, XT or HS
modes.
3.7.2
TWO-SPEED START-UP
SEQUENCE
1. Wake-up from Power-on Reset or Sleep.
2. Instructions begin execution by the internal
oscillator at the frequency set in the IRCF<2:0>
bits of the OSCCON register.
3. OST enabled to count 1024 clock cycles.
3.7
Two-Speed Clock Start-up Mode
4. OST timed out, wait for falling edge of the
internal oscillator.
Two-Speed Start-up mode provides additional power
savings by minimizing the latency between external
oscillator start-up and code execution. In applications
that make heavy use of the Sleep mode, Two-Speed
Start-up will remove the external oscillator start-up
time from the time spent awake and can reduce the
overall power consumption of the device.
5. OSTS is set.
6. System clock held low until the next falling edge
of new clock (LP, XT or HS mode).
7. System clock is switched to external clock
source.
This mode allows the application to wake-up from
Sleep, perform a few instructions using the INTOSC
as the clock source and go back to Sleep without
waiting for the primary oscillator to become stable.
Note:
Executing a SLEEP instruction will abort
the oscillator start-up time and will cause
the OSTS bit of the OSCCON register to
remain clear.
© 2007 Microchip Technology Inc.
DS41202F-page 27
PIC16F684
3.7.3
CHECKING TWO-SPEED CLOCK
STATUS
Checking the state of the OSTS bit of the OSCCON
register will confirm if the microcontroller is running
from the external clock source, as defined by the
FOSC<2:0> bits in the Configuration Word register
(CONFIG), or the internal oscillator.
FIGURE 3-7:
TWO-SPEED START-UP
HFINTOSC
TOST
OSC1
0
1
1022 1023
OSC2
PC - N
PC + 1
Program Counter
PC
System Clock
DS41202F-page 28
© 2007 Microchip Technology Inc.
PIC16F684
3.8.3
FAIL-SAFE CONDITION CLEARING
3.8
Fail-Safe Clock Monitor
The Fail-Safe condition is cleared after a Reset,
executing a SLEEPinstruction or toggling the SCS bit
of the OSCCON register. When the SCS bit is toggled,
the OST is restarted. While the OST is running, the
device continues to operate from the INTOSC selected
in OSCCON. When the OST times out, the Fail-Safe
condition is cleared and the device will be operating
from the external clock source. The Fail-Safe condition
must be cleared before the OSFIF flag can be cleared.
The Fail-Safe Clock Monitor (FSCM) allows the device
to continue operating should the external oscillator fail.
The FSCM can detect oscillator failure any time after
the Oscillator Start-up Timer (OST) has expired. The
FSCM is enabled by setting the FCMEN bit in the
Configuration Word register (CONFIG). The FSCM is
applicable to all external oscillator modes (LP, XT, HS,
EC, RC and RCIO).
FIGURE 3-8:
FSCM BLOCK DIAGRAM
3.8.4
RESET OR WAKE-UP FROM SLEEP
Clock Monitor
Latch
The FSCM is designed to detect an oscillator failure
after the Oscillator Start-up Timer (OST) has expired.
The OST is used after waking up from Sleep and after
any type of Reset. The OST is not used with the EC or
RC Clock modes so that the FSCM will be active as
soon as the Reset or wake-up has completed. When
the FSCM is enabled, the Two-Speed Start-up is also
enabled. Therefore, the device will always be executing
code while the OST is operating.
External
Clock
S
Q
LFINTOSC
Oscillator
÷ 64
R
Q
31 kHz
(~32 μs)
488 Hz
(~2 ms)
Note:
Due to the wide range of oscillator start-up
times, the Fail-Safe circuit is not active
during oscillator start-up (i.e., after exiting
Reset or Sleep). After an appropriate
amount of time, the user should check the
OSTS bit of the OSCCON register to verify
the oscillator start-up and that the system
Sample Clock
Clock
Failure
Detected
3.8.1
FAIL-SAFE DETECTION
The FSCM module detects a failed oscillator by
comparing the external oscillator to the FSCM sample
clock. The sample clock is generated by dividing the
LFINTOSC by 64. See Figure 3-8. Inside the fail
detector block is a latch. The external clock sets the
latch on each falling edge of the external clock. The
sample clock clears the latch on each rising edge of the
sample clock. A failure is detected when an entire
half-cycle of the sample clock elapses before the
primary clock goes low.
clock
completed.
switchover
has
successfully
3.8.2
FAIL-SAFE OPERATION
When the external clock fails, the FSCM switches the
device clock to an internal clock source and sets the bit
flag OSFIF of the PIR1 register. Setting this flag will
generate an interrupt if the OSFIE bit of the PIE1
register is also set. The device firmware can then take
steps to mitigate the problems that may arise from a
failed clock. The system clock will continue to be
sourced from the internal clock source until the device
firmware successfully restarts the external oscillator
and switches back to external operation.
The internal clock source chosen by the FSCM is
determined by the IRCF<2:0> bits of the OSCCON
register. This allows the internal oscillator to be
configured before a failure occurs.
© 2007 Microchip Technology Inc.
DS41202F-page 29
PIC16F684
FIGURE 3-9:
FSCM TIMING DIAGRAM
Sample Clock
Oscillator
Failure
System
Clock
Output
Clock Monitor Output
(Q)
Failure
Detected
OSCFIF
Test
Test
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.
TABLE 3-2:
SUMMARY OF REGISTERS ASSOCIATED WITH CLOCK SOURCES
Value on
Value on:
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
all other
POR, BOR
(1)
Resets
(2)
CONFIG
CPD
—
CP
IRCF2
—
MCLRE PWRTE
WDTE
OSTS
TUN3
C1IE
FOSC2
HTS
FOSC1
LTS
FOSC0
SCS
—
—
OSCCON
OSCTUNE
PIE1
IRCF1
—
IRCF0
TUN4
C2IE
-110 x000 -110 x000
---0 0000 ---u uuuu
—
TUN2
TUN1
TUN0
EEIE
EEIF
ADIE
ADIF
CCP1IE
CCP1IF
OSFIE TMR2IE TMR1IE 0000 0000 0000 0000
OSFIF TMR2IF TMR1IF 0000 0000 0000 0000
PIR1
C2IF
C1IF
Legend:
x= unknown, u= unchanged, –= unimplemented locations read as ‘0’. Shaded cells are not used by oscillators.
Note 1: Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
2: See Configuration Word register (Register 12-1) for operation of all register bits.
DS41202F-page 30
© 2007 Microchip Technology Inc.
PIC16F684
port pins are read, this value is modified and then
written to the PORT data latch. RA3 reads ‘0’ when
MCLRE = 1.
4.0
I/O PORTS
There are as many as twelve general purpose I/O pins
available. Depending on which peripherals are enabled,
some or all of the pins may not be available as general
purpose I/O. In general, when a peripheral is enabled,
the associated pin may not be used as a general
purpose I/O pin.
The TRISA register controls the direction of the
PORTA 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. I/O pins configured as analog input always read
‘0’.
4.1
PORTA and the TRISA Registers
Note:
The ANSEL and CMCON0 registers must
be initialized to configure an analog
channel as a digital input. Pins configured
as analog inputs will read ‘0’.
PORTA is
a 6-bit wide, bidirectional port. The
corresponding data direction register is TRISA
(Register 4-2). Setting a TRISA bit (= 1) will make the
corresponding PORTA pin an input (i.e., disable the
output driver). Clearing a TRISA bit (= 0) will make the
corresponding PORTA pin an output (i.e., enables output
driver and puts the contents of the output latch on the
selected pin). The exception is RA3, which is input only
and its TRIS bit will always read as ‘1’. Example 4-1
shows how to initialize PORTA.
EXAMPLE 4-1:
INITIALIZING PORTA
BCF
CLRF
STATUS,RP0
PORTA
;Bank 0
;Init PORTA
MOVLW 07h
MOVWF CMCON0
;Set RA<2:0> to
;digital I/O
;Bank 1
;digital I/O
;Set RA<3:2> as inputs
;and set RA<5:4,1:0>
;as outputs
BSF
CLRF
STATUS,RP0
ANSEL
Reading the PORTA register (Register 4-1) reads the
status of the pins, whereas writing to it will write to the
PORT latch. All write operations are read-modify-write
operations. Therefore, a write to a port implies that the
MOVLW 0Ch
MOVWF TRISA
BCF
STATUS,RP0
;Bank 0
REGISTER 4-1:
PORTA: PORTA REGISTER
U-0
—
U-0
—
R/W-x
RA5
R/W-0
RA4
R-x
R/W-0
RA2
R/W-0
RA1
R/W-0
RA0
RA3
bit 7
bit 0
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
bit 7-6
bit 5-0
Unimplemented: Read as ‘0’
RA<5:0>: PORTA I/O Pin bit
1= PORTA pin is > VIH
0= PORTA pin is < VIL
REGISTER 4-2:
TRISA: PORTA TRI-STATE REGISTER
U-0
—
U-0
—
R/W-1
R/W-1
R-1
R/W-1
R/W-1
R/W-1
TRISA5
TRISA4
TRISA3
TRISA2
TRISA1
TRISA0
bit 0
bit 7
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
bit 7-6
bit 5-0
Unimplemented: Read as ‘0’
TRISA<5:0>: PORTA Tri-State Control bit
1= PORTA pin configured as an input (tri-stated)
0= PORTA pin configured as an output
Note 1: TRISA<3> always reads ‘1’.
2: TRISA<5:4> always reads ‘1’ in XT, HS and LP OSC modes.
© 2007 Microchip Technology Inc.
DS41202F-page 31
PIC16F684
4.2.3
INTERRUPT-ON-CHANGE
4.2
Additional Pin Functions
Each of the PORTA pins is individually configurable as
an interrupt-on-change pin. Control bits IOCAx enable
or disable the interrupt function for each pin. Refer to
Register 4-5. The interrupt-on-change is disabled on a
Power-on Reset.
Every PORTA pin on the PIC16F684 has an
interrupt-on-change option and a weak pull-up option.
RA0 has an Ultra Low-Power Wake-up option. The next
three sections describe these functions.
4.2.1
ANSEL REGISTER
For enabled interrupt-on-change pins, the values are
compared with the old value latched on the last read of
PORTA. The ‘mismatch’ outputs of the last read are
OR’d together to set the PORTA Change Interrupt Flag
bit (RAIF) in the INTCON register (Register 2-3).
The ANSEL register is used to configure the Input
mode of an I/O pin to analog. Setting the appropriate
ANSEL bit high will cause all digital reads on the pin to
be read as ‘0’ and allow analog functions on the pin to
operate correctly.
This interrupt can wake the device from Sleep. The
user, in the Interrupt Service Routine, clears the inter-
rupt by:
The state of the ANSEL bits has no affect on digital
output functions. A pin with TRIS clear and ANSEL set
will still operate as a digital output, but the Input mode
will be analog. This can cause unexpected behavior
when executing read-modify-write instructions on the
affected port.
a) Any read or write of PORTA. This will end the
mismatch condition, then,
b) Clear the flag bit RAIF.
A mismatch condition will continue to set flag bit RAIF.
Reading PORTA will end the mismatch condition and
allow flag bit RAIF to be cleared. The latch holding the
last read value is not affected by a MCLR nor
Brown-out Reset. After these resets, the RAIF flag will
continue to be set if a mismatch is present.
4.2.2
WEAK PULL-UPS
Each of the PORTA pins, except RA3, has an
individually configurable internal weak pull-up. Control
bits WPUAx enable or disable each pull-up. Refer to
Register 4-4. Each 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 by the
RAPU bit of the OPTION register). A weak pull-up is
automatically enabled for RA3 when configured as
MCLR and disabled when RA3 is an I/O. There is no
software control of the MCLR pull-up.
Note:
If a change on the I/O pin should occur
when any PORTA operation is being
executed, then the RAIF interrupt flag may
not get set.
REGISTER 4-3:
ANSEL: ANALOG SELECT REGISTER
R/W-1
ANS7
R/W-1
ANS6
R/W-1
ANS5
R/W-1
ANS4
R/W-1
ANS3
R/W-1
ANS2
R/W-1
ANS1
R/W-1
ANS0
bit 7
bit 0
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
bit 7-0
ANS<7:0>: Analog Select bits
Analog select between analog or digital function on pins AN<7:0>, respectively.
1= Analog input. Pin is assigned as analog input(1)
0= Digital I/O. Pin is assigned to port or special function.
.
Note 1: Setting a pin to an analog input automatically disables the digital input circuitry, weak pull-ups and
interrupt-on-change, if available. The corresponding TRIS bit must be set to Input mode in order to allow
external control of the voltage on the pin.
DS41202F-page 32
© 2007 Microchip Technology Inc.
PIC16F684
REGISTER 4-4:
WPUA: WEAK PULL-UP PORTA REGISTER
U-0
—
U-0
—
R/W-1
R/W-1
U-0
—
R/W-1
R/W-1
R/W-1
WPUA5
WPUA4
WPUA2
WPUA1
WPUA0
bit 7
bit 0
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
bit 7-6
bit 5-4
Unimplemented: Read as ‘0’
WPUA<5:4>: Weak Pull-up Control bits
1= Pull-up enabled
0= Pull-up disabled
bit 3
Unimplemented: Read as ‘0’
bit 2-0
WPUA<2:0>: Weak Pull-up Control bits
1= Pull-up enabled
0= Pull-up disabled
Note 1: Global RAPU must be enabled for individual pull-ups to be enabled.
2: The weak pull-up device is automatically disabled if the pin is in Output mode (TRISA = 0).
3: The RA3 pull-up is enabled when configured as MCLR and disabled as an I/O in the Configuration Word.
4: WPUA<5:4> always reads ‘1’ in XT, HS and LP OSC modes.
REGISTER 4-5:
IOCA: INTERRUPT-ON-CHANGE PORTA REGISTER
U-0
—
U-0
—
R/W-0
IOCA5
R/W-0
IOCA4
R/W-0
IOCA3
R/W-0
IOCA2
R/W-0
IOCA1
R/W-0
IOCA0
bit 7
bit 0
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
bit 7-6
bit 5-0
Unimplemented: Read as ‘0’
IOCA<5:0>: Interrupt-on-change PORTA Control bit
1= Interrupt-on-change enabled
0= Interrupt-on-change disabled
Note 1: Global Interrupt Enable (GIE) must be enabled for individual interrupts to be recognized.
2: IOCA<5:4> always reads ‘1’ in XT, HS and LP OSC modes.
© 2007 Microchip Technology Inc.
DS41202F-page 33
PIC16F684
4.2.4
ULTRA LOW-POWER WAKE-UP
The Ultra Low-Power Wake-Up (ULPWU) on RA0
Note:
For more information, refer to AN879,
“Using the Microchip Ultra Low-Power
Wake-Up Module” Application Note
(DS00879).
allows
a
slow falling voltage to generate an
interrupt-on-change on RA0 without excess current
consumption. The mode is selected by setting the
ULPWUE bit of the PCON register. This enables a small
current sink which can be used to discharge a capacitor
on RA0.
EXAMPLE 4-2:
ULTRA LOW-POWER
WAKE-UP INITIALIZATION
To use this feature, the RA0 pin is first configured to output
‘1’ to charge the capacitor. Then interrupt-on-change for
RA0 is enabled, and RA0 is configured as an input. The
ULPWUE bit is set to begin the discharge and a SLEEP
instruction is performed. When the voltage on RA0 drops
below VIL, the device will wake-up and execute the next
instruction. If the GIE bit of the INTCON register is set, the
device will call the interrupt service routine (0004h). See
BANKSELCMCON0
;
MOVLW
MOVWF
H’7’
CMCON0
;Turn off
;comparators
;
;RA0 to digital I/O
;Output high to
;
;charge capacitor
;
;
BANKSELANSEL
BCF
BCF
ANSEL,0
TRISA,0
BANKSELPORTA
BSF
CALL
PORTA,0
CapDelay
Section 4.2.3
“Interrupt-on-Change”
and
BANKSELPCON
Section 12.4.3 “PORTA Interrupt-on-Change” for
more information.
BSF
PCON,ULPWUE ;Enable ULP Wake-up
BSF
IOCA,0
;Select RA0 IOC
;RA0 to input
BSF
TRISA,0
This feature provides a low-power technique for
periodically waking up the device from Sleep. The
time-out is dependent on the discharge time of the RC
circuit on RA0. See Example 4-2 for initializing the Ultra
Low-Power Wake-Up module.
MOVLW
MOVWF
SLEEP
B’10001000’ ;Enable interrupt
INTCON
; and clear flag
;Wait for IOC
The series resistor provides overcurrent protection for
the RA0 pin and can allow for software calibration of
the time-out (see Figure 4-1). A timer can be used to
measure the charge time and discharge time of the
capacitor. The charge time can then be adjusted to
provide the desired interrupt delay. This technique will
compensate for the affects of temperature, voltage and
component accuracy. The Ultra Low-Power Wake-Up
peripheral can also be configured as a simple
Programmable Low Voltage Detect or temperature
sensor.
DS41202F-page 34
© 2007 Microchip Technology Inc.
PIC16F684
4.2.5
PIN DESCRIPTIONS AND
DIAGRAMS
4.2.5.2
RA1/AN1/C1IN-/VREF/ICSPCLK
Figure 4-2 shows the diagram for this pin. The RA1 pin
is configurable to function as one of the following:
Each PORTA pin is multiplexed with other functions.
The pins and their combined functions are briefly
described here. For specific information about
individual functions such as the Comparator or the
ADC, refer to the appropriate section in this data sheet.
• a general purpose I/O
• an analog input for the ADC
• an analog inverting input to the comparator
• a voltage reference input for the ADC
• In-Circuit Serial Programming clock
4.2.5.1
RA0/AN0/C1IN+/ICSPDAT/ULPWU
Figure 4-1 shows the diagram for this pin. The RA0 pin
is configurable to function as one of the following:
• a general purpose I/O
• an analog input for the ADC
• an analog non-inverting input to the comparator
• In-Circuit Serial Programming data
• an analog input for the Ultra Low-Power Wake-Up
FIGURE 4-1:
BLOCK DIAGRAM OF RA0
Analog(1)
Input Mode
VDD
Data Bus
D
Q
Q
Weak
CK
WR
WPUA
RAPU
VDD
RD
WPUA
D
Q
Q
I/O Pin
WR
CK
PORTA
VSS
-
+
VT
D
Q
Q
WR
TRISA
CK
IULP
0
1
RD
TRISA
Analog(1)
Input Mode
VSS
ULPWUE
RD
PORTA
D
Q
Q
Q
D
D
CK
WR
IOCA
Q3
EN
RD
IOCA
Q
EN
Interrupt-on-
Change
RD PORTA
To Comparator
To A/D Converter
Note 1: Comparator mode and ANSEL determines Analog Input mode.
© 2007 Microchip Technology Inc.
DS41202F-page 35
PIC16F684
FIGURE 4-2:
BLOCK DIAGRAM OF RA1
4.2.5.3
RA2/AN2/T0CKI/INT/C1OUT
Figure 4-3 shows the diagram for this pin. The RA2 pin
is configurable to function as one of the following:
Analog(1)
Input Mode
Data Bus
D
Q
Q
VDD
Weak
• a general purpose I/O
WR
CK
• an analog input for the ADC
• the clock input for TMR0
WPUA
RAPU
RD
WPUA
• an external edge triggered interrupt
• a digital output from Comparator 1
VDD
FIGURE 4-3:
BLOCK DIAGRAM OF RA2
D
Q
Q
Analog(1)
Input Mode
WR
PORTA
CK
Data Bus
D
Q
Q
VDD
I/O Pin
WR
WPUA
CK
D
Q
Q
Weak
WR
TRISA
CK
VSS
RAPU
RD
WPUA
Analog(1)
Input Mode
RD
TRISA
C1OUT
Enable
VDD
D
Q
Q
RD
PORTA
WR
PORTA
CK
C1OUT
1
0
D
Q
Q
Q
D
D
CK
WR
IOCA
I/O Pin
D
Q
Q
EN
Q3
WR
TRISA
RD
IOCA
CK
VSS
Q
Analog(1)
Input Mode
RD
TRISA
EN
Interrupt-on-
Change
RD
PORTA
RD PORTA
D
Q
Q
To Comparator
To A/D Converter
Q
Q
D
CK
WR
IOCA
Q3
EN
Note 1: Comparator mode and ANSEL determines Analog
Input mode.
RD
IOCA
D
EN
Interrupt-on-
Change
RD PORTA
To Timer0
To INT
To A/D Converter
Note 1: Analog Input mode is generated by ANSEL.
DS41202F-page 36
© 2007 Microchip Technology Inc.
PIC16F684
4.2.5.4
RA3/MCLR/VPP
4.2.5.5
RA4/AN3/T1G/OSC2/CLKOUT
Figure 4-4 shows the diagram for this pin. The RA3 pin
is configurable to function as one of the following:
Figure 4-5 shows the diagram for this pin. The RA4 pin
is configurable to function as one of the following:
• a general purpose input
• a general purpose I/O
• as Master Clear Reset with weak pull-up
• an analog input for the ADC
• a Timer1 gate (count enable)
• a crystal/resonator connection
• a clock output
FIGURE 4-4:
BLOCK DIAGRAM OF RA3
VDD
MCLRE
Weak
FIGURE 4-5:
BLOCK DIAGRAM OF RA4
Analog(3)
Input Mode
Data Bus
MCLRE
Reset
CLK(1)
Modes
VDD
Input
Pin
Data Bus
D
RD
TRISA
VSS
Q
Q
MCLRE
VSS
WR
CK
Weak
RD
PORTA
WPUA
D
Q
Q
RAPU
RD
WPUA
Q
Q
D
Oscillator
Circuit
CK
WR
IOCA
OSC1
Q3
EN
VDD
CLKOUT
Enable
RD
IOCA
D
FOSC/4
1
0
D
Q
Q
EN
Interrupt-on-
Change
I/O Pin
WR
CK
PORTA
CLKOUT
Enable
RD PORTA
VSS
D
Q
Q
INTOSC/
RC/EC(2)
WR
TRISA
CK
CLKOUT
Enable
RD
TRISA
Analog
Input Mode
RD
PORTA
D
Q
Q
Q
D
D
CK
WR
IOCA
Q3
EN
RD
IOCA
Q
EN
Interrupt-on-
Change
RD PORTA
To T1G
To A/D Converter
Note 1: CLK modes are XT, HS, LP, LPTMR1 and CLKOUT
Enable.
2: With CLKOUT option.
3: Analog Input mode comes from ANSEL.
© 2007 Microchip Technology Inc.
DS41202F-page 37
PIC16F684
4.2.5.6
RA5/T1CKI/OSC1/CLKIN
Figure 4-6 shows the diagram for this pin. The RA5 pin
is configurable to function as one of the following:
• a general purpose I/O
• a Timer1 clock input
• a crystal/resonator connection
• a clock input
FIGURE 4-6:
BLOCK DIAGRAM OF RA5
INTOSC
Mode
TMR1LPEN(1)
VDD
Data Bus
D
Q
Q
WR
CK
Weak
WPUA
RAPU
RD
WPUA
Oscillator
Circuit
OSC2
VDD
D
Q
Q
WR
PORTA
CK
I/O Pin
D
Q
Q
WR
TRISA
CK
VSS
INTOSC
Mode
RD
TRISA
RD
PORTA
D
Q
Q
Q
Q
D
CK
WR
IOCA
Q3
EN
RD
IOCA
D
EN
Interrupt-on-
Change
RD PORTA
To Timer1
Note 1: Timer1 LP Oscillator enabled.
DS41202F-page 38
© 2007 Microchip Technology Inc.
PIC16F684
TABLE 4-1:
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Value on
Value on:
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
all other
POR, BOR
Resets
ANSEL
CMCON0
PCON
ANS7
ANS6
ANS5
ANS4
ANS3
CIS
ANS2
CM2
—
ANS1
CM1
ANS0
CM0
1111 1111
0000 0000
--01 --qq
1111 1111
0000 0000
--0u --uu
C2OUT C1OUT C2INV
C1INV
—
GIE
—
—
PEIE
—
ULPWUE SBOREN
—
POR
BOR
INTCON
IOCA
T0IE
INTE
IOCA4
T0SE
RA4
RAIE
IOCA3
T0IF
IOCA2
INTF
IOCA1
RAIF
IOCA0
0000 0000
--00 0000
0000 0000
--00 0000
IOCA5
OPTION_REG RAPU INTEDG T0CS
PSA
RA3
PS2
RA2
PS1
RA1
PS0
RA0
1111 1111
--x0 x000
1111 1111
--uu uu00
--11 1111
--11 -111
PORTA
TRISA
—
—
—
—
—
—
RA5
TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 --11 1111
WPUA5 WPUA4 WPUA2 WPUA1 WPUA0 --11 -111
WPUA
Legend:
—
x= unknown, u= unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA.
© 2007 Microchip Technology Inc.
DS41202F-page 39
PIC16F684
EXAMPLE 4-3:
BANKSELPORTC
INITIALIZING PORTC
4.3
PORTC
;
PORTC is a general purpose I/O port consisting of 6
bidirectional pins. The pins can be configured for either
digital I/O or analog input to A/D Converter (ADC) or
Comparator. For specific information about individual
functions such as the Enhanced CCP or the ADC, refer
to the appropriate section in this data sheet.
CLRF
MOVLW
MOVWF
BANKSELANSEL
CLRF
PORTC
07h
CMCON0
;Init PORTC
;Set RC<4,1:0> to
;digital I/O
;
;digital I/O
;Set RC<3:2> as inputs
;and set RC<5:4,1:0>
;as outputs
;Bank 0
ANSEL
0Ch
TRISC
MOVLW
MOVWF
Note:
The ANSEL and CMCON0 registers must
be initialized to configure an analog chan-
nel as a digital input. Pins configured as
analog inputs will read ‘0’.
BCF
STATUS,RP0
REGISTER 4-6:
PORTC: PORTC REGISTER
U-0
—
U-0
—
R/W-x
RC5
R/W-x
RC4
R/W-0
RC3
R/W-0
RC2
R/W-0
RC1
R/W-0
RC0
bit 7
bit 0
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
bit 7-6
bit 5-0
Unimplemented: Read as ‘0’
RC<5:0>: PORTC I/O Pin bit
1= PORTC pin is > VIH
0= PORTC pin is < VIL
REGISTER 4-7:
TRISC: PORTC TRI-STATE REGISTER
U-0
—
U-0
—
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
TRISC5
TRISC4
TRISC3
TRISC2
TRISC1
TRISC0
bit 7
bit 0
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
bit 7-6
bit 5-0
Unimplemented: Read as ‘0’
TRISC<5:0>: PORTC Tri-State Control bit
1= PORTC pin configured as an input (tri-stated)
0= PORTC pin configured as an output
DS41202F-page 40
© 2007 Microchip Technology Inc.
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4.3.1
RC0/AN4/C2IN+
4.3.3
RC2/AN6/P1D
The RC0 is configurable to function as one of the
following:
The RC2 is configurable to function as one of the
following:
• a general purpose I/O
• a general purpose I/O
• an analog input for the ADC
• an analog input for the ADC
• a digital output from the Enhanced CCP
• an analog non-inverting input to the comparator
4.3.2
RC1/AN5/C2IN-
4.3.4
RC3/AN7/P1C
The RC1 is configurable to function as one of the
following:
The RC3 is configurable to function as one of the
following:
• a general purpose I/O
• a general purpose I/O
• an analog input for the ADC
• an analog input for the ADC
• a digital output from the Enhanced CCP
• an analog inverting input to the comparator
FIGURE 4-7:
BLOCK DIAGRAM OF RC0
AND RC1
FIGURE 4-8:
BLOCK DIAGRAM OF RC2
AND RC3
Data Bus
Data Bus
CCPOUT
Enable
VDD
VDD
D
Q
Q
D
CK
Q
Q
WR
PORTC
CK
WR
PORTC
CCPOUT
1
0
I/O Pin
I/O Pin
D
Q
Q
D
Q
Q
WR
WR
TRISC
CK
CK
VSS
Analog Input
TRISC
VSS
Analog Input
Mode(1)
Mode(1)
RD
RD
TRISC
TRISC
RD
RD
PORTC
PORTC
To Comparators
To A/D Converter
To A/D Converter
Note 1: Analog Input mode comes from ANSEL.
Note 1: Analog Input mode comes from ANSEL or
Comparator mode.
© 2007 Microchip Technology Inc.
DS41202F-page 41
PIC16F684
4.3.5
RC4/C2OUT/P1B
4.3.6
RC5/CCP1/P1A
The RC4 is configurable to function as one of the
following:
The RC5 is configurable to function as one of the
following:
• a general purpose I/O
• a general purpose I/O
• a digital input/output for the Enhanced CCP
• a digital output from the comparator
• a digital output from the Enhanced CCP
FIGURE 4-10:
BLOCK DIAGRAM OF RC5
PIN
Note:
Enabling both C2OUT and P1B will cause
a conflict on RC4 and create unpredictable
results. Therefore, if C2OUT is enabled,
the ECCP can not be used in Half-Bridge
or Full-Bridge mode and vice-versa.
Data bus
VDD
CCP1OUT
Enable
D
Q
Q
WR
PORTC
CK
FIGURE 4-9:
BLOCK DIAGRAM OF RC4
CCP1OUT
1
0
I/O Pin
C2OUT EN
CCPOUT EN
D
Q
Q
VDD
WR
TRISC
C2OUT EN
C2OUT
CK
VSS
1
CCPOUT EN
CCPOUT
RD
0
TRISC
Data Bus
D
I/O Pin
Q
Q
RD
PORTC
WR
PORTC
CK
VSS
To Enhanced CCP
D
Q
Q
WR
TRISC
CK
RD
TRISC
RD
PORTC
Note 1:
Port/Peripheral Select signals selects between
port data and peripheral output.
TABLE 4-2:
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
ANSEL
ANS7
ANS6
C1OUT
—
ANS5
C2INV
RC5
ANS4
C1INV
RC4
ANS3
CIS
ANS2
CM2
RC2
ANS1
CM1
ANS0
CM0
RC0
1111 1111 1111 1111
0000 0000 0000 0000
--xx 0000 --uu uu00
CMCON0 C2OUT
PORTC
TRISC
—
—
RC3
RC1
—
TRISC5 TRISC4 TRISC3 TRISC2
TRISC1
TRISC0 --11 1111 --11 1111
Legend:
x= unknown, u= unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by PORTC.
DS41202F-page 42
© 2007 Microchip Technology Inc.
PIC16F684
5.1
Timer0 Operation
5.0
TIMER0 MODULE
When used as a timer, the Timer0 module can be used
as either an 8-bit timer or an 8-bit counter.
The Timer0 module is an 8-bit timer/counter with the
following features:
• 8-bit timer/counter register (TMR0)
5.1.1
8-BIT TIMER MODE
• 8-bit prescaler (shared with Watchdog Timer)
• Programmable internal or external clock source
• Programmable external clock edge selection
• Interrupt on overflow
When used as a timer, the Timer0 module will
increment every instruction cycle (without prescaler).
Timer mode is selected by clearing the T0CS bit of the
OPTION register to ‘0’.
Figure 5-1 is a block diagram of the Timer0 module.
When TMR0 is written, the increment is inhibited for
two instruction cycles immediately following the write.
Note:
The value written to the TMR0 register can
be adjusted, in order to account for the two
instruction cycle delay when TMR0 is
written.
5.1.2
8-BIT COUNTER MODE
When used as a counter, the Timer0 module will
increment on every rising or falling edge of the T0CKI
pin. The incrementing edge is determined by the T0SE
bit of the OPTION register. Counter mode is selected by
setting the T0CS bit of the OPTION register to ‘1’.
FIGURE 5-1:
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
FOSC/4
Data Bus
0
1
8
1
Sync 2
TMR0
cycles
T0CKI
pin
0
0
1
Set Flag bit T0IF
on Overflow
T0CS
T0SE
8-bit
Prescaler
PSA
8
PSA
WDTE
3
SWDTEN
1
PS<2:0>
WDT
Time-out
16-bit
Prescaler
0
16
31 kHz
INTOSC
Watchdog
Timer
PSA
WDTPS<3:0>
Note 1: T0SE, T0CS, PSA, PS<2:0> are bits in the OPTION register.
2: SWDTEN and WDTPS<3:0> are bits in the WDTCON register.
3: WDTE bit is in the Configuration Word register.
© 2007 Microchip Technology Inc.
DS41202F-page 43
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When changing the prescaler assignment from the
WDT to the Timer0 module, the following instruction
sequence must be executed (see Example 5-2).
5.1.3
SOFTWARE PROGRAMMABLE
PRESCALER
A single software programmable prescaler is available
for use with either Timer0 or the Watchdog Timer
(WDT), but not both simultaneously. The prescaler
assignment is controlled by the PSA bit of the OPTION
register. To assign the prescaler to Timer0, the PSA bit
must be cleared to a ‘0’.
EXAMPLE 5-2:
CHANGING PRESCALER
(WDT → TIMER0)
CLRWDT
;Clear WDT and
;prescaler
;
BANKSEL OPTION_REG
There are 8 prescaler options for the Timer0 module
ranging from 1:2 to 1:256. The prescale values are
selectable via the PS<2:0> bits of the OPTION register.
In order to have a 1:1 prescaler value for the Timer0
module, the prescaler must be assigned to the WDT
module.
MOVLW
ANDWF
IORLW
MOVWF
b’11110000’ ;Mask TMR0 select and
OPTION_REG,W ; prescaler bits
b’00000011’ ;Set prescale to 1:16
OPTION_REG
;
5.1.4
TIMER0 INTERRUPT
The prescaler is not readable or writable. When
assigned to the Timer0 module, all instructions writing to
the TMR0 register will clear the prescaler.
Timer0 will generate an interrupt when the TMR0
register overflows from FFh to 00h. The T0IF interrupt
flag bit of the INTCON register is set every time the
TMR0 register overflows, regardless of whether or not
the Timer0 interrupt is enabled. The T0IF bit must be
cleared in software. The Timer0 interrupt enable is the
T0IE bit of the INTCON register.
When the prescaler is assigned to WDT, a CLRWDT
instruction will clear the prescaler along with the WDT.
5.1.3.1
Switching Prescaler Between
Timer0 and WDT Modules
Note:
The Timer0 interrupt cannot wake the
processor from Sleep since the timer is
frozen during Sleep.
As a result of having the prescaler assigned to either
Timer0 or the WDT, it is possible to generate an
unintended device Reset when switching prescaler
values. When changing the prescaler assignment from
Timer0 to the WDT module, the instruction sequence
shown in Example 5-1 must be executed.
5.1.5
USING TIMER0 WITH AN
EXTERNAL CLOCK
When Timer0 is in Counter mode, the synchronization
of the T0CKI input and the Timer0 register is accom-
plished by sampling the prescaler output on the Q2 and
Q4 cycles of the internal phase clocks. Therefore, the
high and low periods of the external clock source must
meet the timing requirements as shown in
Section 15.0 “Electrical Specifications”.
EXAMPLE 5-1:
CHANGING PRESCALER
(TIMER0 → WDT)
BANKSEL TMR0
CLRWDT
;
;Clear WDT
;Clear TMR0 and
CLRF
TMR0
;
;
prescaler
BANKSEL OPTION_REG
BSF
OPTION_REG,PSA ;Select WDT
CLRWDT
;
;
MOVLW
ANDWF
IORLW
MOVWF
b’11111000’
OPTION_REG,W
b’00000101’
OPTION_REG
;Mask prescaler
bits
;Set WDT prescaler
to 1:32
;
;
DS41202F-page 44
© 2007 Microchip Technology Inc.
PIC16F684
REGISTER 5-1:
OPTION_REG: OPTION REGISTER
R/W-1
RAPU
R/W-1
R/W-1
T0CS
R/W-1
T0SE
R/W-1
PSA
R/W-1
PS2
R/W-1
PS1
R/W-1
PS0
INTEDG
bit 7
bit 0
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
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
RAPU: PORTA Pull-up Enable bit
1= PORTA pull-ups are disabled
0= PORTA pull-ups are enabled by individual PORT latch values
INTEDG: Interrupt Edge Select bit
1= Interrupt on rising edge of INT pin
0= Interrupt on falling edge of INT pin
T0CS: TMR0 Clock Source Select bit
1= Transition on T0CKI pin
0= Internal instruction cycle clock (FOSC/4)
T0SE: TMR0 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: Prescaler Assignment bit
1= Prescaler is assigned to the WDT
0= Prescaler is assigned to the Timer0 module
PS<2:0>: Prescaler Rate Select bits
BIT VALUE TMR0 RATE
WDT RATE
000
001
010
011
100
101
110
111
1 : 2
1 : 1
1 : 4
1 : 2
1 : 8
1 : 4
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
Note 1: A dedicated 16-bit WDT postscaler is available. See Section 12.6 “Watchdog Timer (WDT)” for more
information.
TABLE 5-1:
Name
SUMMARY OF REGISTERS ASSOCIATED WITH TIMER0
Value on
all other
Resets
Value on:
POR, BOR
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
TMR0
Timer0 Module Register
GIE PEIE T0IE
xxxx xxxx uuuu uuuu
INTCON
INTE
T0SE
RAIE
PSA
T0IF
PS2
INTF
PS1
RAIF 0000 0000 0000 0000
PS0 1111 1111 1111 1111
OPTION_REG RAPU INTEDG T0CS
TRISA
—
—
TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 --11 1111 --11 1111
Legend: – = Unimplemented locations, read as ‘0’, u= unchanged, x= unknown. Shaded cells are not used by the
Timer0 module.
© 2007 Microchip Technology Inc.
DS41202F-page 45
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NOTES:
DS41202F-page 46
© 2007 Microchip Technology Inc.
PIC16F684
6.1
Timer1 Operation
6.0
TIMER1 MODULE WITH GATE
CONTROL
The Timer1 module is a 16-bit incrementing counter
which is accessed through the TMR1H:TMR1L register
pair. Writes to TMR1H or TMR1L directly update the
counter.
The Timer1 module is a 16-bit timer/counter with the
following features:
• 16-bit timer/counter register pair (TMR1H:TMR1L)
• Programmable internal or external clock source
• 3-bit prescaler
When used with an internal clock source, the module is
a timer. When used with an external clock source, the
module can be used as either a timer or counter.
• Optional LP oscillator
• Synchronous or asynchronous operation
6.2
Clock Source Selection
• Timer1 gate (count enable) via comparator or
T1G pin
The TMR1CS bit of the T1CON register is used to select
the clock source. When TMR1CS = 0, the clock source
is FOSC/4. When TMR1CS = 1, the clock source is
supplied externally.
• Interrupt on overflow
• Wake-up on overflow (external clock,
Asynchronous mode only)
• Time base for the Capture/Compare function
• Special Event Trigger (with ECCP)
Clock Source
TMR1CS
• Comparator output synchronization to Timer1
clock
FOSC/4
0
1
T1CKI pin
Figure 6-1 is a block diagram of the Timer1 module.
FIGURE 6-1:
TIMER1 BLOCK DIAGRAM
TMR1GE
T1GINV
TMR1ON
Set flag bit
To C2 Comparator Module
Timer1 Clock
TMR1IF on
Overflow
(1)
TMR1
TMR1H
Synchronized
clock input
0
EN
*
TMR1L
1
Oscillator
T1SYNC
OSC1/T1CKI
1
Synchronize
Prescaler
1, 2, 4, 8
(2)
FOSC/4
Internal
Clock
det
0
OSC2/T1G
2
T1CKPS<1:0>
TMR1CS
1
0
T1OSCEN
C2OUT
FOSC = 100
FOSC = 000
T1GSS
Sleep
*
ST Buffer is low power type when using LP osc, or high speed type when using T1CKI.
Note 1: Timer1 register increments on rising edge.
2: Synchronize does not operate while in Sleep.
© 2007 Microchip Technology Inc.
DS41202F-page 47
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TRISA5 and TRISA4 bits are set when the Timer1
oscillator is enabled. RA5 and RA4 bits read as ‘0’ and
TRISA5 and TRISA4 bits read as ‘1’.
6.2.1
INTERNAL CLOCK SOURCE
When the internal clock source is selected, the
TMR1H:TMR1L register pair will increment on multiples
of FOSC as determined by the Timer1 prescaler.
Note:
The oscillator requires a start-up and
stabilization time before use. Thus,
T1OSCEN should be set and a suitable
delay observed prior to enabling Timer1.
6.2.2
EXTERNAL CLOCK SOURCE
When the external clock source is selected, the Timer1
module may work as a timer or a counter.
6.5
Timer1 Operation in
Asynchronous Counter Mode
When counting, Timer1 is incremented on the rising
edge of the external clock input T1CKI. In addition, the
Counter mode clock can be synchronized to the
microcontroller system clock or run asynchronously.
If control bit T1SYNC of the T1CON register is set, the
external clock input is not synchronized. The timer
increments asynchronously to the internal phase
clocks. If external clock source is selected then the
timer will continue to run during Sleep and can
generate an interrupt on overflow, which will wake-up
the processor. However, special precautions in
software are needed to read/write the timer (see
Section 6.5.1 “Reading and Writing Timer1 in
Asynchronous Counter Mode”).
If an external clock oscillator is needed (and the
microcontroller is using the INTOSC without CLKOUT),
Timer1 can use the LP oscillator as a clock source.
Note:
In Counter mode, a falling edge must be
registered by the counter prior to the first
incrementing rising edge after any one or
more of the following conditions:
• Timer1 enabled after POR reset
• Write to TMR1H or TMR1L
• Timer1 is disabled
Note:
When switching from synchronous to
asynchronous operation, it is possible to
skip an increment. When switching from
asynchronous to synchronous operation,
it is possible to produce an additional
increment.
• Timer1 is disabled (TMR1ON 0) when
T1CKI is high then Timer1 is enabled
(TMR1ON=1) when T1CKI is low.
See Figure 6-2
6.5.1
READING AND WRITING TIMER1 IN
ASYNCHRONOUS COUNTER
MODE
6.3
Timer1 Prescaler
Timer1 has four prescaler options allowing 1, 2, 4 or 8
divisions of the clock input. The T1CKPS bits of the
T1CON register control the prescale counter. The
prescale counter is not directly readable or writable;
however, the prescaler counter is cleared upon a write to
TMR1H or TMR1L.
Reading TMR1H or TMR1L while the timer is running
from an external asynchronous clock will ensure a valid
read (taken care of in hardware). However, the user
should keep in mind that reading the 16-bit timer in two
8-bit values itself, poses certain problems, since the
timer may overflow or carry out of TMR1L to TMR1H
between the reads.
6.4
Timer1 Oscillator
For writes, it is recommended that the user simply stop
the timer and write the desired values. A write
contention may occur by writing to the timer registers,
while the register is incrementing. This may produce an
unpredictable value in the TMR1H:TMR1L register pair.
A low-power 32.768 kHz crystal oscillator is built-in
between pins OSC1 (input) and OSC2 (amplifier
output). The oscillator is enabled by setting the
T1OSCEN control bit of the T1CON register. The
oscillator will continue to run during Sleep.
The Timer1 oscillator is shared with the system LP
oscillator. Thus, Timer1 can use this mode only when
the primary system clock is derived from the internal
oscillator or when the oscillator is in the LP mode. The
user must provide a software time delay to ensure
proper oscillator start-up.
DS41202F-page 48
© 2007 Microchip Technology Inc.
PIC16F684
6.6
Timer1 Gate
6.9
ECCP Capture/Compare Time Base
Timer1 gate source is software configurable to be the
T1G pin or the output of Comparator 2. This allows the
device to directly time external events using T1G or
analog events using Comparator 2. See the CMCON1
register (Register 8-2) for selecting the Timer1 gate
source. This feature can simplify the software for a
Delta-Sigma A/D converter and many other applications.
For more information on Delta-Sigma A/D converters,
see the Microchip web site (www.microchip.com).
The ECCP module uses the TMR1H:TMR1L register
pair as the time base when operating in Capture or
Compare mode.
In Capture mode, the value in the TMR1H:TMR1L
register pair is copied into the CCPR1H:CCPR1L
register pair on a configured event.
In Compare mode, an event is triggered when the value
CCPR1H:CCPR1L register pair matches the value in
the TMR1H:TMR1L register pair. This event can be a
Special Event Trigger.
Note:
TMR1GE bit of the T1CON register must
be set to use either T1G or C2OUT as the
Timer1 gate source. See the CMCON1
register (Register 8-2) for more informa-
tion on selecting the Timer1 gate source.
For more information, see Section 11.0 “Enhanced
Capture/Compare/PWM (With Auto-Shutdown and
Dead Band) Module”.
Timer1 gate can be inverted using the T1GINV bit of
the T1CON register, whether it originates from the T1G
pin or Comparator 2 output. This configures Timer1 to
measure either the active-high or active-low time
between events.
6.10 ECCP Special Event Trigger
When the ECCP is configured to trigger a special
event, the trigger will clear the TMR1H:TMR1L register
pair. This special event does not cause a Timer1
interrupt. The ECCP module may still be configured to
generate a ECCP interrupt.
6.7
Timer1 Interrupt
In this mode of operation, the CCPR1H:CCPR1L
register pair effectively becomes the period register for
Timer1.
The Timer1 register pair (TMR1H:TMR1L) increments
to FFFFh and rolls over to 0000h. When Timer1 rolls
over, the Timer1 interrupt flag bit of the PIR1 register is
set. To enable the interrupt on rollover, you must set
these bits:
Timer1 should be synchronized to the FOSC to utilize
the Special Event Trigger. Asynchronous operation of
Timer1 can cause a Special Event Trigger to be
missed.
• TMR1ON bit or the T1CON register
• TMR1IE bit of the PIE1 register
• PEIE bit of the INTCON register
• GIE bit of the INTCON register
In the event that a write to TMR1H or TMR1L coincides
with a Special Event Trigger from the ECCP, the write
will take precedence.
The interrupt is cleared by clearing the TMR1IF bit in
the Interrupt Service Routine.
For more information, see Section 11.2.4 “Special
Event Trigger”.
Note:
The TMR1H:TTMR1L register pair and the
TMR1IF bit should be cleared before
enabling interrupts.
6.11 Comparator Synchronization
The same clock used to increment Timer1 can also be
used to synchronize the comparator output. This
feature is enabled in the Comparator module.
6.8
Timer1 Operation During Sleep
Timer1 can only operate during Sleep when setup in
Asynchronous Counter mode. In this mode, an external
crystal or clock source can be used to increment the
counter. To set up the timer to wake the device:
When using the comparator for Timer1 gate, the
comparator output should be synchronized to Timer1.
This ensures Timer1 does not miss an increment if the
comparator changes.
• TMR1ON bit of the T1CON register must be set
• TMR1IE bit of the PIE1 register must be set
• PEIE bit of the INTCON register must be set
• T1SYNC bit of the T1CON register
For more information, see Section 8.9 “Synchronizing
Comparator C2 Output to Timer1”.
• TMR1CS bit of the T1CON register
• T1OSCEN bit of the T1CON register (can be set)
The device will wake-up on an overflow and execute
the next instruction. If the GIE bit of the INTCON
register is set, the device will call the Interrupt Service
Routine (0004h).
© 2007 Microchip Technology Inc.
DS41202F-page 49
PIC16F684
FIGURE 6-2:
TIMER1 INCREMENTING EDGE
T1CKI = 1
when TMR1
Enabled
T1CKI = 0
when TMR1
Enabled
Note 1: Arrows indicate counter increments.
2: In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge of the clock.
6.12 Timer1 Control Register
The Timer1 Control register (T1CON), shown in
Register 6-1, is used to control Timer1 and select the
various features of the Timer1 module.
REGISTER 6-1:
T1CON: TIMER 1 CONTROL REGISTER
R/W-0
T1GINV(1)
R/W-0
TMR1GE(2)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
T1CKPS1
T1CKPS0
T1OSCEN
T1SYNC
TMR1CS
TMR1ON
bit 7
bit 0
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
bit 7
bit 6
T1GINV: Timer1 Gate Invert bit(1)
1= Timer1 gate is active high (Timer1 counts when gate is high)
0= Timer1 gate is active low (Timer1 counts when gate is low)
TMR1GE: Timer1 Gate Enable bit(2)
If TMR1ON = 0:
This bit is ignored
If TMR1ON = 1:
1= Timer1 is on if Timer1 gate is not active
0= Timer1 is on
bit 5-4
bit 3
T1CKPS<1:0>: 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
T1OSCEN: LP Oscillator Enable Control bit
If INTOSC without CLKOUT oscillator is active:
1= LP oscillator is enabled for Timer1 clock
0= LP oscillator is off
Else:
This bit is ignored
DS41202F-page 50
© 2007 Microchip Technology Inc.
PIC16F684
REGISTER 6-1:
T1CON: TIMER 1 CONTROL REGISTER (CONTINUED)
bit 2
T1SYNC: Timer1 External Clock Input Synchronization Control bit
TMR1CS = 1:
1= Do not synchronize external clock input
0= Synchronize external clock input
TMR1CS = 0:
This bit is ignored. Timer1 uses the internal clock
bit 1
bit 0
TMR1CS: Timer1 Clock Source Select bit
1= External clock from T1CKI pin (on the rising edge)
0= Internal clock (FOSC/4)
TMR1ON: Timer1 On bit
1= Enables Timer1
0= Stops Timer1
Note 1: T1GINV bit inverts the Timer1 gate logic, regardless of source.
2: TMR1GE bit must be set to use either T1G pin or C2OUT, as selected by the T1GSS bit of the CMCON1
register, as a Timer1 gate source.
TABLE 6-1:
SUMMARY OF REGISTERS ASSOCIATED WITH TIMER1
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
CMCON1
INTCON
PIE1
—
—
—
—
—
—
T1GSS
INTF
C2SYNC
RAIF
---- --10
0000 0000
0000 0000
0000 0000
xxxx xxxx
xxxx xxxx
0000 0000
---- --10
0000 0000
0000 0000
0000 0000
uuuu uuuu
uuuu uuuu
uuuu uuuu
GIE
PEIE
ADIE
ADIF
T0IE
INTE
C2IE
C2IF
RAIE
C1IE
C1IF
T0IF
EEIE
EEIF
CCP1IE
CCP1IF
OSFIE
OSFIF
TMR2IE
TMR2IF
TMR1IE
TMR1IF
PIR1
TMR1H
TMR1L
T1CON
Legend:
Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
T1GINV
TMR1GE T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
TMR1CS
TMR1ON
x= unknown, u= unchanged, —= unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module.
© 2007 Microchip Technology Inc.
DS41202F-page 51
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NOTES:
DS41202F-page 52
© 2007 Microchip Technology Inc.
PIC16F684
The TMR2 and PR2 registers are both fully readable
and writable. On any Reset, the TMR2 register is set to
00h and the PR2 register is set to FFh.
7.0
TIMER2 MODULE
The Timer2 module is an eight-bit timer with the
following features:
Timer2 is turned on by setting the TMR2ON bit in the
T2CON register to a ‘1’. Timer2 is turned off by clearing
the TMR2ON bit to a ‘0’.
• 8-bit timer register (TMR2)
• 8-bit period register (PR2)
• Interrupt on TMR2 match with PR2
• Software programmable prescaler (1:1, 1:4, 1:16)
• Software programmable postscaler (1:1 to 1:16)
The Timer2 prescaler is controlled by the T2CKPS bits
in the T2CON register. The Timer2 postscaler is
controlled by the TOUTPS bits in the T2CON register.
The prescaler and postscaler counters are cleared
when:
See Figure 7-1 for a block diagram of Timer2.
• A write to TMR2 occurs.
• A write to T2CON occurs.
7.1
Timer2 Operation
The clock input to the Timer2 module is the system
instruction clock (FOSC/4). The clock is fed into the
Timer2 prescaler, which has prescale options of 1:1,
1:4 or 1:16. The output of the prescaler is then used to
increment the TMR2 register.
• Any device Reset occurs (Power-on Reset, MCLR
Reset, Watchdog Timer Reset, or Brown-out
Reset).
Note:
TMR2 is not cleared when T2CON is
written.
The values of TMR2 and PR2 are constantly compared
to determine when they match. TMR2 will increment
from 00h until it matches the value in PR2. When a
match occurs, two things happen:
• TMR2 is reset to 00h on the next increment cycle.
• The Timer2 postscaler is incremented
The match output of the Timer2/PR2 comparator is fed
into the Timer2 postscaler. The postscaler has
postscale options of 1:1 to 1:16 inclusive. The output of
the Timer2 postscaler is used to set the TMR2IF
interrupt flag bit in the PIR1 register.
FIGURE 7-1:
TIMER2 BLOCK DIAGRAM
Sets Flag
bit TMR2IF
TMR2
Output
Prescaler
Reset
EQ
TMR2
FOSC/4
1:1, 1:4, 1:16
Postscaler
1:1 to 1:16
2
Comparator
PR2
T2CKPS<1:0>
4
TOUTPS<3:0>
© 2007 Microchip Technology Inc.
DS41202F-page 53
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REGISTER 7-1:
T2CON: TIMER 2 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 7
bit 0
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
bit 7
Unimplemented: Read as ‘0’
bit 6-3
TOUTPS<3:0>: Timer2 Output Postscaler Select bits
0000= 1:1 Postscaler
0001= 1:2 Postscaler
0010= 1:3 Postscaler
0011= 1:4 Postscaler
0100= 1:5 Postscaler
0101= 1:6 Postscaler
0110= 1:7 Postscaler
0111= 1:8 Postscaler
1000= 1:9 Postscaler
1001= 1:10 Postscaler
1010= 1:11 Postscaler
1011= 1:12 Postscaler
1100= 1:13 Postscaler
1101= 1:14 Postscaler
1110= 1:15 Postscaler
1111= 1:16 Postscaler
bit 2
TMR2ON: Timer2 On bit
1= Timer2 is on
0= Timer2 is off
bit 1-0
T2CKPS<1:0>: Timer2 Clock Prescale Select bits
00= Prescaler is 1
01= Prescaler is 4
1x= Prescaler is 16
TABLE 7-1:
SUMMARY OF ASSOCIATED TIMER2 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
PIE1
GIE
EEIE
EEIF
PEIE
ADIE
ADIF
T0IE
INTE
C2IE
C2IF
RAIE
C1IE
C1IF
T0IF
INTF
RAIF
0000 0000
0000 0000
0000 0000
0000 0000
1111 1111
0000 0000
-000 0000
CCP1IE
CCP1IF
OSFIE
OSFIF
TMR2IE
TMR2IF
TMR1IE 0000 0000
TMR1IF 0000 0000
1111 1111
PIR1
PR2
Timer2 Module Period Register
Holding Register for the 8-bit TMR2 Register
TMR2
T2CON
Legend:
0000 0000
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000
x= unknown, u= unchanged, —= unimplemented read as ‘0’. Shaded cells are not used for Timer2 module.
DS41202F-page 54
© 2007 Microchip Technology Inc.
PIC16F684
8.1
Comparator Overview
8.0
COMPARATOR MODULE
A comparator is shown in Figure 8-1 along with the
relationship between the analog input levels and the
digital output. When the analog voltage at VIN+ is less
than the analog voltage at VIN-, the output of the
comparator is a digital low level. When the analog
voltage at VIN+ is greater than the analog voltage at
VIN-, the output of the comparator is a digital high level.
Comparators are used to interface analog circuits to a
digital circuit by comparing two analog voltages and
providing a digital indication of their relative magnitudes.
The comparators are very useful mixed signal building
blocks because they provide analog functionality
independent of the device program execution. The
analog Comparator module includes the following
features:
FIGURE 8-1:
SINGLE COMPARATOR
• Dual comparators
• Multiple comparator configurations
VIN+
VIN-
• Comparator outputs are available internally/
externally
+
Output
–
• Programmable output polarity
• Interrupt-on-change
• Wake-up from Sleep
• Timer1 gate (count enable)
• Output synchronization to Timer1 clock input
• Programmable voltage reference
VIN-
VIN+
Note:
Only Comparator C2 can be linked to
Timer1.
Output
Note:
The black areas of the output of the
comparator represents the uncertainty
due to input offsets and response time.
This device contains two comparators as shown in
Figure 8-2 and Figure 8-3. The comparators are not
independently configurable.
© 2007 Microchip Technology Inc.
DS41202F-page 55
PIC16F684
FIGURE 8-2:
COMPARATOR C1 OUTPUT BLOCK DIAGRAM
C1INV
To C1OUT pin
To Data Bus
C1
D
Q
Q
Q1
EN
RD CMCON0
Set C1IF bit
D
Q3*RD CMCON0
EN
CL
Reset
Note 1: Q1 and Q3 are phases of the four-phase system clock (FOSC).
2: Q1 is held high during Sleep mode.
FIGURE 8-3:
COMPARATOR C2 OUTPUT BLOCK DIAGRAM
C2SYNC
To Timer1 Gate
To C2OUT pin
C2INV
0
1
C2
D
Q
Timer1
clock source
(1)
To Data Bus
Set C2IF bit
D
Q
Q
Q1
EN
RD CMCON0
D
Q3*RD CMCON0
EN
CL
Reset
Note 1: Comparator output is latched on falling edge of Timer1 clock source.
2: Q1 and Q3 are phases of the four-phase system clock (FOSC).
3: Q1 is held high during Sleep mode.
DS41202F-page 56
© 2007 Microchip Technology Inc.
PIC16F684
8.1.1
ANALOG INPUT CONNECTION
CONSIDERATIONS
Note 1: When reading a PORT register, all pins
configured as analog inputs will read as a
‘0’. Pins configured as digital inputs will
convert as an analog input, according to
the input specification.
A simplified circuit for an analog input is shown in
Figure 8-4. Since the analog input pins share their con-
nection with a digital input, they have reverse biased
ESD protection diodes to VDD and VSS. The analog
input, therefore, must be between VSS and VDD. If the
input voltage deviates from this range by more than
0.6V in either direction, one of the diodes is forward
biased and a latch-up may occur.
2: Analog levels on any pin defined as a
digital input, may cause the input buffer to
consume more current than is specified.
A maximum source impedance of 10 kΩ is recommended
for the analog sources. Also, any external component
connected to an analog input pin, such as a capacitor or
a Zener diode, should have very little leakage current to
minimize inaccuracies introduced.
FIGURE 8-4:
ANALOG INPUT MODEL
VDD
VT ≈ 0.6V
RIC
Rs < 10K
To ADC Input
AIN
ILEAKAGE
±500 nA
CPIN
5 pF
VA
VT ≈ 0.6V
Vss
Legend: CPIN
= Input Capacitance
ILEAKAGE = Leakage Current at the pin due to various junctions
RIC
RS
VA
= Interconnect Resistance
= Source Impedance
= Analog Voltage
VT
= Threshold Voltage
© 2007 Microchip Technology Inc.
DS41202F-page 57
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The port pins denoted as “A” will read as a ‘0’
regardless of the state of the I/O pin or the I/O control
TRIS bit. Pins used as analog inputs should also have
the corresponding TRIS bit set to ‘1’ to disable the
digital output driver. Pins denoted as “D” should have
the corresponding TRIS bit set to ‘0’ to enable the
digital output driver.
8.2
Comparator Configuration
There are eight modes of operation for the comparator.
The CM<2:0> bits of the CMCON0 register are used to
select these modes as shown in Figure 8-5. I/O lines
change as a function of the mode and are designated
as follows:
• Analog function (A): digital input buffer is disabled
• Digital function (D): comparator digital output,
overrides port function
• Normal port function (I/O): independent of
comparator
Note:
Comparator interrupts should be disabled
during a Comparator mode change to
prevent unintended interrupts.
FIGURE 8-5:
COMPARATOR I/O OPERATING MODES
Two Independent Comparators
Comparators Reset (POR Default Value)
CM<2:0> = 100
CM<2:0> = 000
A
VIN-
A
A
VIN-
C1IN-
C1IN-
(1)
(1)
Off
C1
C2
C1OUT
C2OUT
C1
C2
VIN+
A
VIN+
C1IN+
C1IN+
A
A
A
A
VIN-
VIN-
C2IN-
C2IN+
C2IN-
C2IN+
Off
VIN+
VIN+
Three Inputs Multiplexed to Two Comparators
One Independent Comparator
CM<2:0> = 001
CM<2:0> = 101
A
I/O
VIN-
C1IN-
C1IN-
CIS = 0 VIN-
(1)
A
CIS = 1
Off
C1
VIN+
I/O
C1IN+
C1OUT
C2OUT
C1
C2
C1IN+
VIN+
A
A
A
A
VIN-
VIN-
C2IN-
C2IN+
C2IN-
C2IN+
C2OUT
C2
VIN+
VIN+
Four Inputs Multiplexed to Two Comparators
CM<2:0> = 010
Two Common Reference Comparators with Outputs
CM<2:0> = 110
A
A
VIN-
C1IN-
C1IN-
CIS = 0
CIS = 1
VIN-
C1OUT
C2OUT
C1
C2
A
VIN+
C1IN+
C1OUT
C2OUT
C1
C2
VIN+
D
C1OUT(pin)
A
A
C2IN-
C2IN+
CIS = 0
CIS = 1
VIN-
A
A
VIN-
C2IN-
C2IN+
VIN+
VIN+
D
C2OUT(pin)
From CVREF Module
Comparators Off (Lowest Power)
CM<2:0> = 111
Two Common Reference Comparators
CM<2:0> = 011
A
I/O
VIN-
VIN-
C1IN-
C1IN-
(1)
C1OUT
C2OUT
Off
C1
C1
VIN+
VIN+
I/O
I/O
C1IN+
C1IN+
A
A
I/O
I/O
VIN-
VIN-
C2IN-
C2IN+
C2IN-
C2IN+
(1)
Off
C2
C2
VIN+
VIN+
Legend: A = Analog Input, ports always reads ‘0’
CIS = Comparator Input Switch (CMCON0<3>)
D = Comparator Digital Output
I/O = Normal port I/O
Note 1: Reads as ‘0’, unless CxINV = 1.
DS41202F-page 58
© 2007 Microchip Technology Inc.
PIC16F684
8.3
Comparator Control
8.4
Comparator Response Time
The CMCON0 register (Register 8-1) provides access
to the following comparator features:
The comparator output is indeterminate for a period of
time after the change of an input source or the selection
of a new reference voltage. This period is referred to as
the response time. The response time of the
comparator differs from the settling time of the voltage
reference. Therefore, both of these times must be
considered when determining the total response time
to a comparator input change. See Comparator and
Voltage Reference specifications of Section 15.0
“Electrical Specifications” for more details.
• Mode selection
• Output state
• Output polarity
• Input switch
8.3.1
COMPARATOR OUTPUT STATE
Each comparator state can always be read internally
via the associated CxOUT bit of the CMCON0 register.
The comparator outputs are directed to the CxOUT
pins when CM<2:0> = 110. When this mode is
selected, the TRIS bits for the associated CxOUT pins
must be cleared to enable the output drivers.
8.5
Comparator Interrupt Operation
The comparator interrupt flag is set whenever there is
a change in the output value of the comparator.
Changes are recognized by means of a mismatch
circuit which consists of two latches and an exclusive-
or gate (see Figure 8-2 and Figure 8-3). One latch is
updated with the comparator output level when the
CMCON0 register is read. This latch retains the value
until the next read of the CMCON0 register or the
occurrence of a reset. The other latch of the mismatch
circuit is updated on every Q1 system clock. A
mismatch condition will occur when a comparator
output change is clocked through the second latch on
the Q1 clock cycle. The mismatch condition will persist,
holding the CxIF bit of the PIR1 register true, until either
the CMCON0 register is read or the comparator output
returns to the previous state.
8.3.2
COMPARATOR OUTPUT POLARITY
Inverting the output of a comparator is functionally
equivalent to swapping the comparator inputs. The
polarity of a comparator output can be inverted by set-
ting the CxINV bits of the CMCON0 register. Clearing
CxINV results in a non-inverted output. A complete
table showing the output state versus input conditions
and the polarity bit is shown in Table 8-1.
TABLE 8-1:
OUTPUT STATE VS. INPUT
CONDITIONS
Input Conditions
CxINV
CxOUT
Note:
A write operation to the CMCON0 register
will also clear the mismatch condition
VIN- > VIN+
VIN- < VIN+
VIN- > VIN+
VIN- < VIN+
0
0
1
1
0
1
1
0
because all writes include
a
read
operation at the beginning of the write
cycle.
Note:
CxOUT refers to both the register bit and
output pin.
Software will need to maintain information about the
status of the comparator output to determine the actual
change that has occurred.
8.3.3
COMPARATOR INPUT SWITCH
The CxIF bit of the PIR1 register is the comparator
interrupt flag. This bit must be reset in software by
clearing it to ‘0’. Since it is also possible to write a ‘1’ to
this register, a simulated interrupt may be initiated.
The inverting input of the comparators may be switched
between two analog pins in the following modes:
• CM<2:0> = 001(Comparator C1 only)
The CxIE bit of the PIE1 register and the PEIE and GIE
bits of the INTCON register must all be set to enable
comparator interrupts. If any of these bits are cleared,
the interrupt is not enabled, although the CxIF bit of the
PIR1 register will still be set if an interrupt condition
occurs.
• CM<2:0> = 010(Comparators C1 and C2)
In the above modes, both pins remain in Analog mode
regardless of which pin is selected as the input. The CIS
bit of the CMCON0 register controls the comparator
input switch.
The user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a) Any read or write of CMCON0. This will end the
mismatch condition.
b) Clear the CxIF interrupt flag.
© 2007 Microchip Technology Inc.
DS41202F-page 59
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A persistent mismatch condition will preclude clearing
the CxIF interrupt flag. Reading CMCON0 will end the
mismatch condition and allow the CxIF bit to be
cleared.
8.6
Operation During Sleep
The comparator, if enabled before entering Sleep mode,
remains active during Sleep. The additional current
consumed by the comparator is shown separately in
Section 15.0 “Electrical Specifications”. If the
comparator is not used to wake the device, power
consumption can be minimized while in Sleep mode by
turning off the comparator. The comparator is turned off
by selecting mode CM<2:0> = 000or CM<2:0> = 111
of the CMCON0 register.
FIGURE 8-6:
COMPARATOR
INTERRUPT TIMING W/O
CMCON0 READ
Q1
Q3
CxIN+
CxOUT
Set CMIF (level)
CMIF
TRT
A change to the comparator output can wake-up the
device from Sleep. To enable the comparator to wake
the device from Sleep, the CxIE bit of the PIE1 register
and the PEIE bit of the INTCON register must be set.
The instruction following the Sleep instruction always
executes following a wake from Sleep. If the GIE bit of
the INTCON register is also set, the device will then
execute the interrupt service routine.
reset by software
FIGURE 8-7:
COMPARATOR
INTERRUPT TIMING WITH
CMCON0 READ
8.7
Effects of a Reset
Q1
A device Reset forces the CMCON0 and CMCON1
registers to their Reset states. This forces the Compar-
ator module to be in the Comparator Reset mode
(CM<2:0> = 000). Thus, all comparator inputs are
analog inputs with the comparator disabled to consume
the smallest current possible.
Q3
CxIN+
CxOUT
Set CMIF (level)
CMIF
TRT
cleared by CMCON0 read
reset by software
Note 1: If a change in the CM1CON0 register
(CxOUT) should occur when a read oper-
ation is being executed (start of the Q2
cycle), then the CxIF Interrupt Flag bit of
the PIR1 register may not get set.
2: When either comparator is first enabled,
bias circuitry in the Comparator module
may cause an invalid output from the
comparator until the bias circuitry is stable.
Allow about 1 μs for bias settling then clear
the mismatch condition and interrupt flags
before enabling comparator interrupts.
DS41202F-page 60
© 2007 Microchip Technology Inc.
PIC16F684
REGISTER 8-1:
CMCON0: COMPARATOR CONFIGURATION REGISTER
R-0
C2OUT
bit 7
R-0
R/W-0
C2INV
R/W-0
C1INV
R/W-0
CIS
R/W-0
CM2
R/W-0
CM1
R/W-0
CM0
C1OUT
bit 0
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
bit 7
C2OUT: Comparator 2 Output bit
When C2INV = 0:
1= C2 VIN+ > C2 VIN-
0= C2 VIN+ < C2 VIN-
When C2INV = 1:
1= C2 VIN+ < C2 VIN-
0= C2 VIN+ > C2 VIN-
bit 6
C1OUT: Comparator 1 Output bit
When C1INV = 0:
1= C1 VIN+ > C1 VIN-
0= C1 VIN+ < C1 VIN-
When C1INV = 1:
1= C1 VIN+ < C1 VIN-
0= C1 VIN+ > C1 VIN-
bit 5
bit 4
bit 3
C2INV: Comparator 2 Output Inversion bit
1= C2 output inverted
0= C2 output not inverted
C1INV: Comparator 1 Output Inversion bit
1= C1 Output inverted
0= C1 Output not inverted
CIS: Comparator Input Switch bit
When CM<2:0> = 010:
1= C1IN+ connects to C1 VIN-
C2IN+ connects to C2 VIN-
0= C1IN- connects to C1 VIN-
C2IN- connects to C2 VIN-
When CM<2:0> = 001:
1= C1IN+ connects to C1 VIN-
0= C1IN- connects to C1 VIN-
bit 2-0
CM<2:0>: Comparator Mode bits (See Figure 8-5)
000= Comparators off. CxIN pins are configured as analog
001= Three inputs multiplexed to two comparators
010= Four inputs multiplexed to two comparators
011= Two common reference comparators
100= Two independent comparators
101= One independent comparator
110= Two common reference comparators with outputs
111= Comparators off. CxIN pins are configured as digital I/O
© 2007 Microchip Technology Inc.
DS41202F-page 61
PIC16F684
8.8
Comparator C2 Gating Timer1
8.9
Synchronizing Comparator C2
Output to Timer1
This feature can be used to time the duration or interval
of analog events. Clearing the T1GSS bit of the
CMCON1 register will enable Timer1 to increment
based on the output of Comparator C2. This requires
that Timer1 is on and gating is enabled. See
Section 6.0 “Timer1 Module with Gate Control” for
details.
The output of Comparator C2 can be synchronized with
Timer1 by setting the C2SYNC bit of the CMCON1
register. When enabled, the comparator output is
latched on the falling edge of the Timer1 clock source.
If a prescaler is used with Timer1, the comparator
output is latched after the prescaling function. To
prevent a race condition, the comparator output is
latched on the falling edge of the Timer1 clock source
and Timer1 increments on the rising edge of its clock
source. Reference the comparator block diagrams
(Figure 8-2 and Figure 8-3) and the Timer1 Block
Diagram (Figure 6-1) for more information.
It is recommended to synchronize Comparator C2 with
Timer1 by setting the C2SYNC bit when the comparator
is used as the Timer1 gate source. This ensures Timer1
does not miss an increment if the comparator changes
during an increment.
REGISTER 8-2:
CMCON1: COMPARATOR CONFIGURATION REGISTER
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
R/W-1
R/W-0
T1GSS
C2SYNC
bit 7
bit 0
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
bit 7-2
bit 1
Unimplemented: Read as ‘0’
T1GSS: Timer1 Gate Source Select bit(1)
1= Timer1 gate source is T1G pin (pin should be configured as digital input)
0= Timer1 gate source is Comparator C2 output
bit 0
C2SYNC: Comparator C2 Output Synchronization bit(2)
1= Output is synchronized with falling edge of Timer1 clock
0= Output is asynchronous
Note 1: Refer to Section 6.6 “Timer1 Gate”.
2: Refer to Figure 8-3.
DS41202F-page 62
© 2007 Microchip Technology Inc.
PIC16F684
EQUATION 8-1:
CVREF OUTPUT VOLTAGE
8.10 Comparator Voltage Reference
VRR = 1 (low range):
CVREF = (VR<3:0>/24) × VDD
VRR = 0 (high range):
CVREF = (VDD/4) +
The comparator voltage reference module provides an
internally generated voltage reference for the compara-
tors. The following features are available:
• Independent from Comparator operation
• Two 16-level voltage ranges
• Output clamped to VSS
(VR<3:0> × VDD/32)
The full range of VSS to VDD cannot be realized due to
the construction of the module. See Figure 8-8.
• Ratiometric with VDD
The VRCON register (Register ) controls the voltage
reference module shown in Figure 8-8.
8.10.3
OUTPUT CLAMPED TO VSS
The CVREF output voltage can be set to Vss with no
power consumption by configuring VRCON as follows:
8.10.1
INDEPENDENT OPERATION
• VREN = 0
The comparator voltage reference is independent of
the comparator configuration. Setting the VREN bit of
the VRCON register will enable the voltage reference.
• VRR = 1
• VR<3:0> = 0000
This allows the comparator to detect a zero-crossing
while not consuming additional CVREF module current.
8.10.2
OUTPUT VOLTAGE SELECTION
The CVREF voltage reference has 2 ranges with 16
voltage levels in each range. Range selection is
controlled by the VRR bit of the VRCON register. The
16 levels are set with the VR<3:0> bits of the VRCON
register.
8.10.4
OUTPUT RATIOMETRIC TO VDD
The comparator voltage reference is VDD derived and
therefore, the CVREF output changes with fluctuations in
VDD. The tested absolute accuracy of the Comparator
Voltage Reference can be found in Section 15.0
“Electrical Specifications”.
The CVREF output voltage is determined by the following
equations:
VRCON: VOLTAGE REFERENCE CONTROL REGISTER
R/W-0
VREN
U-0
—
R/W-0
VRR
U-0
—
R/W-0
VR3
R/W-0
VR2
R/W-0
VR1
R/W-0
VR0
bit 7
bit 0
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
bit 7
VREN: CVREF Enable bit
1= CVREF circuit powered on
0= CVREF circuit powered down, no IDD drain and CVREF = VSS.
bit 6
bit 5
Unimplemented: Read as ‘0’
VRR: CVREF Range Selection bit
1= Low range
0= High range
bit 4
Unimplemented: Read as ‘0’
bit 3-0
VR<3:0>: CVREF Value Selection bits (0 ≤ VR<3:0> ≤ 15)
When VRR = 1: CVREF = (VR<3:0>/24) * VDD
When VRR = 0: CVREF = VDD/4 + (VR<3:0>/32) * VDD
© 2007 Microchip Technology Inc.
DS41202F-page 63
PIC16F684
FIGURE 8-8:
COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
16 Stages
8R
R
R
R
R
VDD
VRR
8R
16-1 Analog
MUX
VREN
15
14
CVREF to
Comparator
Input
2
1
0
(1)
VR<3:0>
VREN
VR<3:0> = 0000
VRR
Note 1: Care should be taken to ensure VREF remains
within the comparator common mode input range.
See Section 15.0 “Electrical Specifications” for
more detail.
TABLE 8-2:
SUMMARY OF REGISTERS ASSOCIATED WITH THE COMPARATOR AND VOLTAGE
REFERENCE MODULES
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
ANSEL
CMCON0
CMCON1
INTCON
PIE1
ANS7
C2OUT
—
ANS6
C1OUT
—
ANS5
C2INV
—
ANS4
C1INV
—
ANS3
CIS
ANS2
CM2
—
ANS1
CM1
ANS0
CM0
1111 1111 1111 1111
0000 0000 0000 0000
---- --10 ---- --10
0000 0000 0000 0000
0000 0000 0000 0000
0000 0000 0000 0000
--x0 x000 --uu uu00
--xx 0000 --uu uu00
--11 1111 --11 1111
--11 1111 --11 1111
0-0- 0000 0-0- 0000
—
T1GSS
INTF
C2SYNC
RAIF
GIE
EEIE
EEIF
—
PEIE
ADIE
ADIF
—
T0IE
INTE
C2IE
C2IF
RA4
RAIE
C1IE
C1IF
RA3
RC3
T0IF
CCP1IE
CCP1IF
RA5
OSFIE TMR2IE
OSFIF TMR2IF
TMR1IE
TMR1IF
RA0
PIR1
PORTA
PORTC
TRISA
RA2
RC2
RA1
RC1
—
—
RC5
RC4
RC0
—
—
TRISA5 TRISA4 TRISA3 TRISA2 TRISA1
TRISC5 TRISC4 TRISC3 TRISC2 TRISC1
TRISA0
TRISC0
VR0
TRISC
—
—
VRCON
VREN
—
VRR
—
VR3
VR2
VR1
Legend:
x= unknown, u= unchanged, -= unimplemented, read as ‘0’. Shaded cells are not used for comparator.
DS41202F-page 64
© 2007 Microchip Technology Inc.
PIC16F684
9.0
ANALOG-TO-DIGITAL
CONVERTER (ADC) MODULE
The Analog-to-Digital Converter (ADC) allows
conversion of an analog input signal to a 10-bit binary
representation of that signal. This device uses analog
inputs, which are multiplexed into a single sample and
hold circuit. The output of the sample and hold is
connected to the input of the converter. The converter
generates a 10-bit binary result via successive
approximation and stores the conversion result into the
ADC result registers (ADRESL and ADRESH).
The ADC voltage reference is software selectable to
either VDD or a voltage applied to the external reference
pins.
The ADC can generate an interrupt upon completion of
a conversion. This interrupt can be used to wake-up the
device from Sleep.
Figure 9-1 shows the block diagram of the ADC.
FIGURE 9-1:
ADC BLOCK DIAGRAM
VDD
VCFG = 0
VCFG = 1
VREF
RA0/AN0
RA1/AN1/VREF
A/D
RA2/AN2
RA4/AN3
RC0/AN4
RC1/AN5
RC2/AN6
RC3/AN7
10
GO/DONE
0= Left Justify
1= Right Justify
ADFM
ADON
10
ADRESH ADRESL
VSS
4
CHS <3:0>
© 2007 Microchip Technology Inc.
DS41202F-page 65
PIC16F684
9.1.4
CONVERSION CLOCK
9.1
ADC Configuration
The source of the conversion clock is software select-
able via the ADCS bits of the ADCON1 register. There
are seven possible clock options:
When configuring and using the ADC the following
functions must be considered:
• Port configuration
• FOSC/2
• Channel selection
• FOSC/4
• ADC voltage reference selection
• ADC conversion clock source
• Interrupt control
• FOSC/8
• FOSC/16
• FOSC/32
• Results formatting
• FOSC/64
9.1.1
PORT CONFIGURATION
• FRC (dedicated internal oscillator)
The ADC can be used to convert both analog and digital
signals. When converting analog signals, the I/O pin
should be configured for analog by setting the associated
TRIS and ANSEL bits. See the corresponding port
section for more information.
The time to complete one bit conversion is defined as
TAD. One full 10-bit conversion requires 11 TAD periods
as shown in Figure 9-3.
For correct conversion, the appropriate TAD specification
must be met. See A/D conversion requirements in
Section 15.0 “Electrical Specifications” for more
information. Table 9-1 gives examples of appropriate
ADC clock selections.
Note:
Analog voltages on any pin that is defined
as a digital input may cause the input
buffer to conduct excess current.
Note:
Unless using the FRC, any changes in the
system clock frequency will change the
ADC clock frequency, which may
adversely affect the ADC result.
9.1.2
CHANNEL SELECTION
The CHS bits of the ADCON0 register determine which
channel is connected to the sample and hold circuit.
When changing channels, a delay is required before
starting the next conversion. Refer to Section 9.2
“ADC Operation” for more information.
9.1.3
ADC VOLTAGE REFERENCE
The VCFG bit of the ADCON0 register provides control
of the positive voltage reference. The positive voltage
reference can be either VDD or an external voltage
source. The negative voltage reference is always
connected to the ground reference.
TABLE 9-1:
ADC CLOCK PERIOD (TAD) VS. DEVICE OPERATING FREQUENCIES (VDD > 3.0V)
ADC Clock Period (TAD)
Device Frequency (FOSC)
ADC Clock Source
ADCS<2:0>
20 MHz
8 MHz
4 MHz
1 MHz
FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/32
FOSC/64
FRC
000
100
001
101
010
110
x11
100 ns(2)
200 ns(2)
400 ns(2)
800 ns(2)
1.6 μs
250 ns(2)
500 ns(2)
1.0 μs(2)
2.0 μs
500 ns(2)
1.0 μs(2)
2.0 μs
2.0 μs
4.0 μs
8.0 μs(3)
16.0 μs(3)
32.0 μs(3)
64.0 μs(3)
2-6 μs(1,4)
4.0 μs
4.0 μs
8.0 μs(3)
16.0 μs(3)
2-6 μs(1,4)
3.2 μs
2-6 μs(1,4)
8.0 μs(3)
2-6 μs(1,4)
Legend: Shaded cells are outside of recommended range.
Note 1: The FRC source has a typical TAD time of 4 μs for VDD > 3.0V.
2: These values violate the minimum required TAD time.
3: For faster conversion times, the selection of another clock source is recommended.
4: When the device frequency is greater than 1 MHz, the FRC clock source is only recommended if the
conversion will be performed during Sleep.
DS41202F-page 66
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 9-2:
ANALOG-TO-DIGITAL CONVERSION TAD CYCLES
TCY to TAD
TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD9 TAD10 TAD11
b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Conversion Starts
Holding Capacitor is Disconnected from Analog Input (typically 100 ns)
Set GO/DONE bit
ADRESH and ADRESL registers are loaded,
GO bit is cleared,
ADIF bit is set,
Holding capacitor is connected to analog input
9.1.5
INTERRUPTS
9.1.6
RESULT FORMATTING
The ADC module allows for the ability to generate an
interrupt upon completion of an analog-to-digital
conversion. The ADC interrupt flag is the ADIF bit in the
PIR1 register. The ADC interrupt enable is the ADIE bit
in the PIE1 register. The ADIF bit must be cleared in
software.
The 10-bit A/D conversion result can be supplied in two
formats, left justified or right justified. The ADFM bit of
the ADCON0 register controls the output format.
Figure 9-4 shows the two output formats.
Note:
The ADIF bit is set at the completion of
every conversion, regardless of whether
or not the ADC interrupt is enabled.
This interrupt can be generated while the device is
operating or while in Sleep. If the device is in Sleep, the
interrupt will wake-up the device. Upon waking from
Sleep, the next instruction following the SLEEP
instruction is always executed. If the user is attempting
to wake-up from Sleep and resume in-line code
execution, the global interrupt must be disabled. If the
global interrupt is enabled, execution will switch to the
interrupt service routine.
Please see Section 9.1.5 “Interrupts” for more
information.
FIGURE 9-3:
10-BIT A/D CONVERSION RESULT FORMAT
ADRESH
ADRESL
LSB
(ADFM = 0)
MSB
bit 7
bit 0
bit 0
bit 7
bit 7
bit 0
10-bit A/D Result
Unimplemented: Read as ‘0’
(ADFM = 1)
MSB
LSB
bit 0
bit 7
Unimplemented: Read as ‘0’
10-bit A/D Result
© 2007 Microchip Technology Inc.
DS41202F-page 67
PIC16F684
9.2.5
SPECIAL EVENT TRIGGER
9.2
ADC Operation
The ECCP Special Event Trigger allows periodic ADC
measurements without software intervention. When
this trigger occurs, the GO/DONE bit is set by hardware
and the Timer1 counter resets to zero.
9.2.1
STARTING A CONVERSION
To enable the ADC module, the ADON bit of the
ADCON0 register must be set to a ‘1’. Setting the
GO/DONE bit of the ADCON0 register to a ‘1’ will start
the analog-to-digital conversion.
Using the Special Event Trigger does not ensure
proper ADC timing. It is the user’s responsibility to
ensure that the ADC timing requirements are met.
Note:
The GO/DONE bit should not be set in the
same instruction that turns on the ADC.
Refer to Section 9.2.6 “A/D Conversion
Procedure”.
See
Section 11.0
“Enhanced
Capture/Com-
pare/PWM (With Auto-Shutdown and Dead Band)
Module” for more information.
9.2.2
COMPLETION OF A CONVERSION
9.2.6
A/D CONVERSION PROCEDURE
When the conversion is complete, the ADC module will:
This is an example procedure for using the ADC to
perform an Analog-to-Digital conversion:
• Clear the GO/DONE bit
• Set the ADIF flag bit
1. Configure Port:
• Disable pin output driver (See TRIS register)
• Configure pin as analog
• Update the ADRESH:ADRESL registers with new
conversion result
2. Configure the ADC module:
• Select ADC conversion clock
• Configure voltage reference
• Select ADC input channel
• Select result format
9.2.3
TERMINATING A CONVERSION
If a conversion must be terminated before completion,
the GO/DONE bit can be cleared in software. The
ADRESH:ADRESL registers will not be updated with
the partially complete analog-to-digital conversion
sample. Instead, the ADRESH:ADRESL register pair
will retain the value of the previous conversion. Addi-
tionally, a 2 TAD delay is required before another acqui-
sition can be initiated. Following this delay, an input
acquisition is automatically started on the selected
channel.
• Turn on ADC module
3. Configure ADC interrupt (optional):
• Clear ADC interrupt flag
• Enable ADC interrupt
• Enable peripheral interrupt
• Enable global interrupt(1)
4. Wait the required acquisition time(2)
Note:
A device Reset forces all registers to their
Reset state. Thus, the ADC module is
turned off and any pending conversion is
terminated.
.
5. Start conversion by setting the GO/DONE bit.
6. Wait for ADC conversion to complete by one of
the following:
9.2.4
ADC OPERATION DURING SLEEP
• Polling the GO/DONE bit
• Waiting for the ADC interrupt (interrupts
enabled)
The ADC module can operate during Sleep. This
requires the ADC clock source to be set to the FRC
option. When the FRC clock source is selected, the
ADC waits one additional instruction before starting the
conversion. This allows the SLEEP instruction to be
executed, which can reduce system noise during the
conversion. If the ADC interrupt is enabled, the device
will wake-up from Sleep when the conversion
completes. If the ADC interrupt is disabled, the ADC
module is turned off after the conversion completes,
although the ADON bit remains set.
7. Read ADC Result
8. Clear the ADC interrupt flag (required if interrupt
is enabled).
Note 1: The global interrupt can be disabled if the
user is attempting to wake-up from Sleep
and resume in-line code execution.
2: See Section 9.3 “A/D Acquisition
Requirements”.
When the ADC clock source is something other than
FRC, a SLEEP instruction causes the present conver-
sion to be aborted and the ADC module is turned off,
although the ADON bit remains set.
DS41202F-page 68
© 2007 Microchip Technology Inc.
PIC16F684
EXAMPLE 9-1:
A/D CONVERSION
;This code block configures the ADC
;for polling, Vdd reference, Frc clock
;and AN0 input.
;
;Conversion start & polling for completion
; are included.
;
BANKSEL
MOVLW
MOVWF
BANKSEL
BSF
BANKSEL
BSF
BANKSEL
MOVLW
MOVWF
CALL
BSF
BTFSC
GOTO
BANKSEL
MOVF
MOVWF
BANKSEL
MOVF
ADCON1
;
B’01110000’ ;ADC Frc clock
ADCON1
TRISA
TRISA,0
ANSEL
ANSEL,0
ADCON0
B’10000001’ ;Right justify,
ADCON0
SampleTime
ADCON0,GO
ADCON0,GO
$-1
;
;
;Set RA0 to input
;
;Set RA0 to analog
;
; Vdd Vref, AN0, On
;Acquisiton delay
;Start conversion
;Is conversion done?
;No, test again
;
;Read upper 2 bits
;store in GPR space
;
ADRESH
ADRESH,W
RESULTHI
ADRESL
ADRESL,W
RESULTLO
;Read lower 8 bits
;Store in GPR space
MOVWF
© 2007 Microchip Technology Inc.
DS41202F-page 69
PIC16F684
9.2.7
ADC REGISTER DEFINITIONS
The following registers are used to control the operation of the ADC.
REGISTER 9-1:
ADCON0: A/D CONTROL REGISTER 0
R/W-0
ADFM
R/W-0
VCFG
U-0
—
R/W-0
CHS2
R/W-0
CHS1
R/W-0
CHS0
R/W-0
R/W-0
ADON
GO/DONE
bit 7
bit 0
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
bit 7
bit 6
ADFM: A/D Conversion Result Format Select bit
1= Right justified
0= Left justified
VCFG: Voltage Reference bit
1= VREF pin
0= VDD
bit 5
Unimplemented: Read as ‘0’
bit 4-2
CHS<2:0>: Analog Channel Select bits
000= AN0
001= AN1
010= AN2
011= AN3
100= AN4
101= AN5
110= AN6
111= AN7
bit 1
bit 0
GO/DONE: A/D Conversion Status bit
1= A/D conversion cycle in progress. Setting this bit starts an A/D conversion cycle.
This bit is automatically cleared by hardware when the A/D conversion has completed.
0= A/D conversion completed/not in progress
ADON: ADC Enable bit
1= ADC is enabled
0= ADC is disabled and consumes no operating current
REGISTER 9-2:
ADCON1: A/D CONTROL REGISTER 1
U-0
—
R/W-0
R/W-0
R/W-0
U-0
—
U-0
—
U-0
—
U-0
—
ADCS2
ADCS1
ADCS0
bit 7
bit 0
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
bit 7
Unimplemented: Read as ‘0’
bit 6-4
ADCS<2:0>: A/D Conversion Clock Select bits
000= FOSC/2
001= FOSC/8
010= FOSC/32
x11= FRC (clock derived from a dedicated internal oscillator = 500 kHz max)
100= FOSC/4
101= FOSC/16
110= FOSC/64
bit 3-0
Unimplemented: Read as ‘0’
DS41202F-page 70
© 2007 Microchip Technology Inc.
PIC16F684
REGISTER 9-3:
ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 0
R/W-x
ADRES9
bit 7
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
ADRES8
ADRES7
ADRES6
ADRES5
ADRES4
ADRES3
ADRES2
bit 0
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
bit 7-0
ADRES<9:2>: ADC Result Register bits
Upper 8 bits of 10-bit conversion result
REGISTER 9-4:
ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 0
R/W-x
ADRES1
bit 7
R/W-x
R/W-x
—
R/W-x
—
R/W-x
—
R/W-x
—
R/W-x
—
R/W-x
—
ADRES0
bit 0
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
bit 7-6
bit 5-0
ADRES<1:0>: ADC Result Register bits
Lower 2 bits of 10-bit conversion result
Reserved: Do not use.
REGISTER 9-5:
ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 1
R/W-x
—
R/W-x
—
R/W-x
—
R/W-x
—
R/W-x
—
R/W-x
—
R/W-x
R/W-x
ADRES9
ADRES8
bit 0
bit 7
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
bit 7-2
bit 1-0
Reserved: Do not use.
ADRES<9:8>: ADC Result Register bits
Upper 2 bits of 10-bit conversion result
REGISTER 9-6:
ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 1
R/W-x
ADRES7
bit 7
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
ADRES6
ADRES5
ADRES4
ADRES3
ADRES2
ADRES1
ADRES0
bit 0
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
bit 7-0
ADRES<7:0>: ADC Result Register bits
Lower 8 bits of 10-bit conversion result
© 2007 Microchip Technology Inc.
DS41202F-page 71
PIC16F684
9.3
A/D Acquisition Requirements
For the ADC 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 9-4. 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), see Figure 9-4.
The maximum recommended impedance for analog
sources is 10 kΩ. As the source impedance is
decreased, the acquisition time may be decreased.
After the analog input channel is selected (or changed),
an A/D acquisition must be done before the conversion
can be started. To calculate the minimum acquisition
time, Equation 9-1 may be used. This equation
assumes that 1/2 LSb error is used (1024 steps for the
ADC). The 1/2 LSb error is the maximum error allowed
for the ADC to meet its specified resolution.
EQUATION 9-1:
ACQUISITION TIME EXAMPLE
Temperature = 50°C and external impedance of 10kΩ 5.0V VDD
Assumptions:
TACQ = Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient
= TAMP + TC + TCOFF
= 5µs + TC + [(Temperature - 25°C)(0.05µs/°C)]
The value for TC can be approximated with the following equations:
1
2047
⎛
⎞
= VCHOLD
-----------
;[1] VCHOLD charged to within 1/2 lsb
VAPPLIED 1 –
⎝
⎠
–TC
---------
⎛
⎞
VAPPLIED 1 – e RC = VCHOLD
;[2] VCHOLD charge response to VAPPLIED
⎜
⎝
⎟
⎠
–Tc
--------
⎛
⎞
1
2047
VAPPLIED 1 – eRC = VAPPLIED 1 –
⎛
⎞
⎠
;combining [1] and [2]
-----------
⎜
⎝
⎟
⎠
⎝
Solving for TC:
TC = –CHOLD(RIC + RSS + RS) ln(1/2047)
= –10pF(1kΩ + 7kΩ + 10kΩ) ln(0.0004885)
= 1.37µs
Therefore:
TACQ = 5µS + 1.37µS + [(50°C- 25°C)(0.05µS/°C)]
= 7.67µS
Note 1: The reference voltage (VREF) has no effect on the equation, since it cancels itself out.
2: The charge holding capacitor (CHOLD) is not discharged after each conversion.
3: The maximum recommended impedance for analog sources is 10 kΩ. This is required to meet the pin
leakage specification.
DS41202F-page 72
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 9-4:
ANALOG INPUT MODEL
VDD
Sampling
Switch
VT = 0.6V
ANx
SS
RIC ≤ 1k
Rss
Rs
CPIN
5 pF
VA
I LEAKAGE
± 500 nA
CHOLD = 10 pF
VSS/VREF-
VT = 0.6V
6V
5V
RSS
VDD 4V
3V
Legend: CPIN
= Input Capacitance
= Threshold Voltage
VT
2V
I LEAKAGE = Leakage current at the pin due to
various junctions
RIC
SS
CHOLD
= Interconnect Resistance
= Sampling Switch
= Sample/Hold Capacitance
5 6 7 8 9 1011
Sampling Switch
(kΩ)
FIGURE 9-5:
ADC TRANSFER FUNCTION
Full-Scale Range
3FFh
3FEh
3FDh
3FCh
3FBh
1 LSB ideal
Full-Scale
Transition
004h
003h
002h
001h
000h
Analog Input Voltage
1 LSB ideal
Zero-Scale
Transition
VDD/VREF+
VSS/VREF-
© 2007 Microchip Technology Inc.
DS41202F-page 73
PIC16F684
TABLE 9-2:
SUMMARY OF ASSOCIATED ADC 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
ADCON0
ADCON1
ANSEL
ADFM
—
VCFG
ADCS2
ANS6
—
CHS2
ADCS0
ANS4
CHS1
—
CHS0
—
GO/DONE ADON 0000 0000 0000 0000
ADCS1
ANS5
—
—
-000 ---- -000 ----
1111 1111 1111 1111
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
0000 0000 0000 0000
ANS7
ANS3
ANS2
ANS1
ANS0
ADRESH A/D Result Register High Byte
ADRESL A/D Result Register Low Byte
INTCON
PIE1
GIE
EEIE
EEIF
—
PEIE
ADIE
ADIF
—
T0IE
CCPIE
CCPIF
RA5
INTE
C2IE
C2IF
RA4
RC4
RAIE
C1IE
C1IF
RA3
T0IF
OSFIE
OSFIF
RA2
INTF
TMR2IE
TMR2IF
RA1
RAIF
TMR1IE 0000 0000 0000 0000
TMR1IF 0000 0000 0000 0000
PIR1
PORTA
PORTC
TRISA
TRISC
Legend:
RA0
RC0
--x0 x000 --uu uuuu
--xx 0000 --uu uuuu
—
—
RC5
RC3
RC2
RC1
—
—
TRISA5 TRISA4 TRISA3 TRISA2
TRISC5 TRISC4 TRISC3 TRISC2
TRISA1
TRISC1
TRISA0 --11 1111 --11 1111
TRISC0 --11 1111 --11 1111
—
—
x= unknown, u= unchanged, —= unimplemented read as ‘0’. Shaded cells are not used for ADC module.
DS41202F-page 74
© 2007 Microchip Technology Inc.
PIC16F684
The EEPROM data memory allows byte read and write.
A byte write automatically erases the location and
writes the new data (erase before write). The EEPROM
data memory is rated for high erase/write cycles. The
write time is controlled by an on-chip timer. The write
time will vary with voltage and temperature as well as
from chip-to-chip. Please refer to AC Specifications in
Section 15.0 “Electrical Specifications” for exact
limits.
10.0 DATA EEPROM MEMORY
The EEPROM data memory is readable and writable
during normal operation (full VDD range). This memory
is not directly mapped in the register file space.
Instead, it is indirectly addressed through the Special
Function Registers. There are four SFRs used to read
and write this memory:
• EECON1
• EECON2 (not a physically implemented register)
When the data memory is code-protected, the CPU
may continue to read and write the data EEPROM
memory. The device programmer can no longer access
the data EEPROM data and will read zeroes.
• EEDAT
• EEADR
EEDAT holds the 8-bit data for read/write, and EEADR
holds the address of the EEPROM location being
accessed. PIC16F684 has 256 bytes of data EEPROM
with an address range from 0h to FFh.
REGISTER 10-1: EEDAT: EEPROM DATA 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
EEDAT7
EEDAT6
EEDAT5
EEDAT4
EEDAT3
EEDAT2
EEDAT1
EEDAT0
bit 7
bit 0
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
bit 7-0
EEDATn: Byte Value to Write To or Read From Data EEPROM bits
REGISTER 10-2: EEADR: EEPROM ADDRESS 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
EEADR7
EEADR6
EEADR5
EEADR4
EEADR3
EEADR2
EEADR1
EEADR0
bit 7
bit 0
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
bit 7-0
EEADR: Specifies One of 256 Locations for EEPROM Read/Write Operation bits
© 2007 Microchip Technology Inc.
DS41202F-page 75
PIC16F684
operation. In these situations, following Reset, the user
can check the WRERR bit, clear it and rewrite the
location. The data and address will be cleared.
Therefore, the EEDAT and EEADR registers will need
to be re-initialized.
10.1 EECON1 and EECON2 Registers
EECON1 is the control register with four low-order bits
physically implemented. The upper four bits are
non-implemented and read as ‘0’s.
Control bits RD and WR initiate read and write,
respectively. These bits cannot be cleared, only set in
software. They are cleared in hardware at completion
of the read or write operation. The inability to clear the
WR bit in software prevents the accidental, premature
termination of a write operation.
Interrupt flag, EEIF bit of the PIR1 register, is set when
write is complete. This bit must be cleared in software.
EECON2 is not a physical register. Reading EECON2
will read all ‘0’s. The EECON2 register is used
exclusively in the data EEPROM write sequence.
Note:
The EECON1, EEDAT and EEADR
registers should not be modified during a
data EEPROM write (WR bit = 1).
The WREN bit, when set, will allow a write operation.
On power-up, the WREN bit is clear. The WRERR bit is
set when a write operation is interrupted by a MCLR
Reset, or a WDT Time-out Reset during normal
REGISTER 10-3: EECON1: EEPROM CONTROL REGISTER
U-0
—
U-0
—
U-0
—
U-0
—
R/W-x
R/W-0
WREN
R/S-0
WR
R/S-0
RD
WRERR
bit 7
bit 0
Legend:
S = Bit can only be set
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
bit 7-4
bit 3
Unimplemented: Read as ‘0’
WRERR: EEPROM Error Flag bit
1= A write operation is prematurely terminated (any MCLR Reset, any WDT Reset during
normal operation or BOR Reset)
0= The write operation completed
bit 2
bit 1
WREN: EEPROM Write Enable bit
1= Allows write cycles
0= Inhibits write to the data EEPROM
WR: Write Control bit
1= Initiates a write cycle (The bit is cleared by hardware once write is complete. The WR bit can only
be set, not cleared, in software.)
0= Write cycle to the data EEPROM is complete
bit 0
RD: Read Control bit
1= Initiates an EEPROM read (Read takes one cycle. RD is cleared in hardware. The RD bit can only
be set, not cleared, in software.)
0= Does not initiate an EEPROM read
DS41202F-page 76
© 2007 Microchip Technology Inc.
PIC16F684
After a write sequence has been initiated, clearing the
WREN bit will not affect this write cycle. The WR bit will
be inhibited from being set unless the WREN bit is set.
10.2 Reading the EEPROM Data
Memory
To read a data memory location, the user must write the
address to the EEADR register and then set control bit
RD of the EECON1 register, as shown in Example 10-1.
The data is available, at the very next cycle, in the
EEDAT register. Therefore, it can be read in the next
instruction. EEDAT holds this value until another read, or
until it is written to by the user (during a write operation).
At the completion of the write cycle, the WR bit is
cleared in hardware and the EE Write Complete
Interrupt Flag bit (EEIF) is set. The user can either
enable this interrupt or poll this bit. The EEIF bit of the
PIR1 register must be cleared by software.
10.4 Write Verify
Depending on the application, good programming
practice may dictate that the value written to the data
EEPROM should be verified (see Example 10-3) to the
desired value to be written.
EXAMPLE 10-1:
DATA EEPROM READ
BANKSEL
MOVLW
MOVWF
BSF
EEADR
;
CONFIG_ADDR;
EEADR
;Address to read
EECON1,RD ;EE Read
MOVF
EEDAT,W
;Move data to W
EXAMPLE 10-3:
WRITE VERIFY
BANKSELEEDAT
;
10.3 Writing to the EEPROM Data
Memory
MOVF
BSF
EEDAT,W
;EEDAT not changed
;from previous write
;YES, Read the
EECON1,RD
;value written
To write an EEPROM data location, the user must first
write the address to the EEADR register and the data
to the EEDAT register. Then the user must follow a
specific sequence to initiate the write for each byte, as
shown in Example 10-2.
XORWF
BTFSS
GOTO
:
EEDAT,W
STATUS,Z
WRITE_ERR
;Is data the same
;No, handle error
;Yes, continue
10.4.1
USING THE DATA EEPROM
high-endurance, byte
EXAMPLE 10-2:
DATA EEPROM WRITE
BANKSEL EECON1
;
The data EEPROM is
a
BSF
EECON1,WREN ;Enable write
addressable array that has been optimized for the
storage of frequently changing information (e.g.,
program variables or other data that are updated often).
When variables in one section change frequently, while
variables in another section do not change, it is possible
to exceed the total number of write cycles to the
EEPROM (specification D124) without exceeding the
BCF
INTCON,GIE
INTCON,GIE
$-2
55h
EECON2
AAh
EECON2
EECON1,WR
INTCON,GIE
;Disable INTs
;See AN576
;
;Unlock write
;
;
;
BTFSC
GOTO
MOVLW
MOVWF
MOVLW
MOVWF
BSF
;Start the write
;Enable INTS
total number of write cycles to
a single byte
BSF
(specifications D120 and D120A). If this is the case,
then a refresh of the array must be performed. For this
reason, variables that change infrequently (such as
constants, IDs, calibration, etc.) should be stored in
Flash program memory.
The write will not initiate if the above sequence is not
exactly followed (write 55h to EECON2, write AAh to
EECON2, then set WR bit) for each byte. We strongly
recommend that interrupts be disabled during this
code segment. A cycle count is executed during the
required sequence. Any number that is not equal to the
required cycles to execute the required sequence will
prevent the data from being written into the EEPROM.
Additionally, the WREN bit in EECON1 must be set to
enable write. This mechanism prevents accidental
writes to data EEPROM due to errant (unexpected)
code execution (i.e., lost programs). The user should
keep the WREN bit clear at all times, except when
updating EEPROM. The WREN bit is not cleared
by hardware.
© 2007 Microchip Technology Inc.
DS41202F-page 77
PIC16F684
10.5 Protection Against Spurious Write
10.6 Data EEPROM Operation During
Code-Protect
There are conditions when the user 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, WREN is cleared. Also, the
Data memory can be code-protected by programming
the CPD bit in the Configuration Word register
(Register 12-1) to ‘0’.
Power-up
Timer
(64 ms
duration)
prevents
When the data memory is code-protected, the CPU is
able to read and write data to the data EEPROM. It is
recommended to code-protect the program memory
when code-protecting data memory. This prevents
anyone from programming zeroes over the existing
code (which will execute as NOPs) to reach an added
routine, programmed in unused program memory,
which outputs the contents of data memory.
Programming unused locations in program memory to
‘0’ will also help prevent data memory code protection
from becoming breached.
EEPROM write.
The write initiate sequence and the WREN bit together
help prevent an accidental write during:
• Brown-out
• Power Glitch
• Software Malfunction
TABLE 10-1: SUMMARY OF ASSOCIATED DATA EEPROM 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
PIR1
GIE
EEIF
EEIE
PEIE
ADIF
ADIE
T0IE
INTE
C2IF
C2IE
RAIE
C1IF
C1IE
T0IF
INTF
RAIF
0000 0000 0000 0000
CCP1IF
CCP1IE
OSFIF
OSFIE
TMR2IF TMR1IF 0000 0000 0000 0000
TMR2IE TMR1IE 0000 0000 0000 0000
PIE1
EEDAT
EEADR
EECON1
EECON2
Legend:
EEDAT7 EEDAT6 EEDAT5 EEDAT4 EEDAT3 EEDAT2 EEDAT1 EEDAT0 0000 0000 0000 0000
EEADR7 EEADR6 EEADR5 EEADR4 EEADR3 EEADR2 EEADR1 EEADR0 0000 0000 0000 0000
—
—
—
—
WRERR
WREN
WR
RD
---- x000 ---- q000
---- ---- ---- ----
(1)
EEPROM Control Register 2
x= unknown, u= unchanged, – = unimplemented read as ‘0’, q= value depends upon condition. Shaded cells are not used by the Data
EEPROM module.
Note 1: EECON2 is not a physical register.
DS41202F-page 78
© 2007 Microchip Technology Inc.
PIC16F684
Table 11-1 shows the timer resources required by the
ECCP module.
11.0 ENHANCED
CAPTURE/COMPARE/PWM
(WITH AUTO-SHUTDOWN AND
DEAD BAND) MODULE
TABLE 11-1: ECCP MODE – TIMER
RESOURCES REQUIRED
The Enhanced Capture/Compare/PWM module is a
peripheral which allows the user to time and control
different events. In Capture mode, the peripheral
allows the timing of the duration of an event. The
Compare mode allows the user to trigger an external
event when a predetermined amount of time has
expired. The PWM mode can generate a Pulse-Width
Modulated signal of varying frequency and duty cycle.
ECCP Mode
Timer Resource
Capture
Compare
PWM
Timer1
Timer1
Timer2
REGISTER 11-1: CCP1CON: ENHANCED CCP1 CONTROL REGISTER
R/W-0
P1M1
R/W-0
P1M0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
CCP1M1
R/W-0
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M0
bit 7
bit 0
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
bit 7-6
P1M<1:0>: PWM Output Configuration bits
If CCP1M<3:2> = 00, 01, 10:
xx= P1A assigned as Capture/Compare input; P1B, P1C, P1D assigned as port pins
If CCP1M<3:2> = 11:
00= Single output; P1A modulated; P1B, P1C, P1D assigned as port pins
01= Full-bridge output forward; P1D modulated; P1A active; P1B, P1C inactive
10= Half-bridge output; P1A, P1B modulated with dead-band control; P1C, P1D assigned as port pins
11= Full-bridge output reverse; P1B modulated; P1C active; P1A, P1D inactive
bit 5-4
DC1B<1:0>: PWM Duty Cycle Least Significant bits
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPR1L.
bit 3-0
CCP1M<3:0>: ECCP Mode Select bits
0000= Capture/Compare/PWM off (resets ECCP module)
0001= Unused (reserved)
0010= Compare mode, toggle output on match (CCP1IF bit is set)
0011= Unused (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, set output on match (CCP1IF bit is set)
1001= Compare mode, clear output on match (CCP1IF bit is set)
1010= Compare mode, generate software interrupt on match (CCP1IF bit is set, CCP1 pin is
unaffected)
1011= Compare mode, trigger special event (CCP1IF bit is set; CCP1 resets TMR1 or TMR2, and starts
an A/D conversion, if the ADC module is enabled)
1100= PWM mode; P1A, P1C active-high; P1B, P1D active-high
1101= PWM mode; P1A, P1C active-high; P1B, P1D active-low
1110= PWM mode; P1A, P1C active-low; P1B, P1D active-high
1111= PWM mode; P1A, P1C active-low; P1B, P1D active-low
© 2007 Microchip Technology Inc.
DS41202F-page 79
PIC16F684
11.1.2
TIMER1 MODE SELECTION
11.1 Capture Mode
Timer1 must be running in Timer mode or Synchronized
Counter mode for the CCP module to use the capture
feature. In Asynchronous Counter mode, the capture
operation may not work.
In Capture mode, CCPR1H:CCPR1L captures the
16-bit value of the TMR1 register when an event occurs
on pin CCP1. An event is defined as one of the
following and is configured by the CCP1M<3:0> bits of
the CCP1CON register:
11.1.3
SOFTWARE INTERRUPT
• Every falling edge
• Every rising edge
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep the
CCP1IE interrupt enable bit of the PIE1 register clear to
avoid false interrupts. Additionally, the user should
clear the CCP1IF interrupt flag bit of the PIR1 register
following any change in operating mode.
• Every 4th rising edge
• Every 16th rising edge
When a capture is made, the Interrupt Request Flag bit
CCP1IF of the PIR1 register is set. The interrupt flag
must be cleared in software. If another capture occurs
before the value in the CCPR1H, CCPR1L register pair
is read, the old captured value is overwritten by the new
captured value (see Figure 11-1).
11.1.4
CCP PRESCALER
There are four prescaler settings specified by the
CCP1M<3:0> bits of the CCP1CON register.
Whenever the CCP module is turned off, or the CCP
module is not in Capture mode, the prescaler counter
is cleared. Any Reset will clear the prescaler counter.
11.1.1
CCP1 PIN CONFIGURATION
In Capture mode, the CCP1 pin should be configured
as an input by setting the associated TRIS control bit.
Switching from one capture prescaler to another does not
clear the prescaler and may generate a false interrupt. To
avoid this unexpected operation, turn the module off by
clearing the CCP1CON register before changing the
prescaler (see Example 11-1).
Note:
If the CCP1 pin is configured as an output,
a write to the port can cause a capture
condition.
FIGURE 11-1:
CAPTURE MODE
OPERATION BLOCK
DIAGRAM
EXAMPLE 11-1:
CHANGING BETWEEN
CAPTURE PRESCALERS
BANKSELCCP1CON
;Set Bank bits to point
;to CCP1CON
;Turn CCP module off
Set Flag bit CCP1IF
(PIR1 register)
Prescaler
÷ 1, 4, 16
CLRF
CCP1CON
MOVLW
NEW_CAPT_PS;Load the W reg with
; the new prescaler
CCP1
pin
CCPR1H
CCPR1L
; move value and CCP ON
Capture
Enable
MOVWF
CCP1CON
;Load CCP1CON with this
; value
and
Edge Detect
TMR1H
TMR1L
CCP1CON<3:0>
System Clock (FOSC)
DS41202F-page 80
© 2007 Microchip Technology Inc.
PIC16F684
11.2.2
TIMER1 MODE SELECTION
11.2 Compare Mode
In Compare mode, Timer1 must be running in either
Timer mode or Synchronized Counter mode. The
compare operation may not work in Asynchronous
Counter mode.
In Compare mode, the 16-bit CCPR1 register value is
constantly compared against the TMR1 register pair
value. When a match occurs, the CCP module may:
• Toggle the CCP1 output
• Set the CCP1 output
11.2.3
SOFTWARE INTERRUPT MODE
• Clear the CCP1 output
When Generate Software Interrupt mode is chosen
(CCP1M<3:0> = 1010), the CCP module does not
assert control of the CCP1 pin (see the CCP1CON
register).
• Generate a Special Event Trigger
• Generate a Software Interrupt
The action on the pin is based on the value of the
CCP1M<3:0> control bits of the CCP1CON register.
11.2.4
SPECIAL EVENT TRIGGER
All Compare modes can generate an interrupt.
When Special Event Trigger mode is chosen
(CCP1M<3:0> = 1011), the CCP module does the
following:
FIGURE 11-2:
COMPARE MODE
OPERATION BLOCK
DIAGRAM
• Resets Timer1
• Starts an ADC conversion if ADC is enabled
CCP1CON<3:0>
Mode Select
The CCP module does not assert control of the CCP1
pin in this mode (see the CCP1CON register).
Set CCP1IF Interrupt Flag
The Special Event Trigger output of the CCP occurs
immediately upon a match between the TMR1H,
TMR1L register pair and the CCPR1H, CCPR1L
register pair. The TMR1H, TMR1L register pair is not
reset until the next rising edge of the Timer1 clock. This
allows the CCPR1H, CCPR1L register pair to
effectively provide a 16-bit programmable period
register for Timer1.
(PIR1)
4
CCP1
Pin
CCPR1H CCPR1L
Comparator
Q
S
R
Output
Logic
Match
TMR1H TMR1L
TRIS
Output Enable
Special Event Trigger
Note 1: The Special Event Trigger from the CCP
module does not set interrupt flag bit
TMR1IF of the PIR1 register.
Special Event Trigger will:
•
•
•
Clear TMR1H and TMR1L registers.
NOT set interrupt flag bit TMR1IF of the PIR1 register.
Set the GO/DONE bit to start the ADC conversion.
2: Removing the match condition by
changing the contents of the CCPR1H
and CCPR1L register pair, between the
clock edge that generates the Special
Event Trigger and the clock edge that
generates the Timer1 Reset, will preclude
the Reset from occurring.
11.2.1
CCP1 PIN CONFIGURATION
The user must configure the CCP1 pin as an output by
clearing the associated TRIS bit.
Note:
Clearing the CCP1CON register will force
the CCP1 compare output latch to the
default low level. This is not the port I/O
data latch.
© 2007 Microchip Technology Inc.
DS41202F-page 81
PIC16F684
The PWM output (Figure 11-4) has a time base
(period) and a time that the output stays high (duty
cycle).
11.3 PWM Mode
The PWM mode generates a Pulse-Width Modulated
signal on the CCP1 pin. The duty cycle, period and
resolution are determined by the following registers:
FIGURE 11-4:
CCP PWM OUTPUT
• PR2
Period
• T2CON
• CCPR1L
• CCP1CON
Pulse Width
TMR2 = PR2
TMR2 = CCPR1L:CCP1CON<5:4>
In Pulse-Width Modulation (PWM) mode, the CCP
module produces up to a 10-bit resolution PWM output
on the CCP1 pin. Since the CCP1 pin is multiplexed
with the PORT data latch, the TRIS for that pin must be
cleared to enable the CCP1 pin output driver.
TMR2 = 0
Note:
Clearing the CCP1CON register will
relinquish CCP1 control of the CCP1 pin.
Figure 11-3 shows a simplified block diagram of PWM
operation.
Figure 11-4 shows a typical waveform of the PWM
signal.
For a step by step procedure on how to set up the CCP
module for PWM operation, see Section 11.3.7
“Setup for PWM Operation”.
FIGURE 11-3:
SIMPLIFIED PWM BLOCK
DIAGRAM
CCP1CON<5:4>
Duty Cycle Registers
CCPR1L
CCPR1H(2) (Slave)
Comparator
CCP1
R
S
Q
(1)
TMR2
TRIS
Comparator
PR2
Clear Timer2,
toggle CCP1 pin and
latch duty cycle
Note 1: The 8-bit timer TMR2 register is concatenated
with the 2-bit internal system clock (FOSC), or
2 bits of the prescaler, to create the 10-bit time
base.
2: In PWM mode, CCPR1H is a read-only register.
DS41202F-page 82
© 2007 Microchip Technology Inc.
PIC16F684
11.3.1
PWM PERIOD
EQUATION 11-2: PULSE WIDTH
The PWM period is specified by the PR2 register of
Timer2. The PWM period can be calculated using the
formula of Equation 11-1.
Pulse Width = (CCPR1L:CCP1CON<5:4>) •
TOSC • (TMR2 Prescale Value)
EQUATION 11-1: PWM PERIOD
EQUATION 11-3: DUTY CYCLE RATIO
PWM Period = [(PR2) + 1] • 4 • TOSC •
(TMR2 Prescale Value)
(CCPR1L:CCP1CON<5:4>)
Duty Cycle Ratio = -----------------------------------------------------------------------
4(PR2 + 1)
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
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.
• TMR2 is cleared
• The CCP1 pin is set. (Exception: If the PWM duty
cycle = 0%, the pin will not be set.)
The 8-bit timer TMR2 register is concatenated with
either the 2-bit internal system clock (FOSC), or 2 bits of
the prescaler, to create the 10-bit time base. The system
clock is used if the Timer2 prescaler is set to 1:1.
• The PWM duty cycle is latched from CCPR1L into
CCPR1H.
Note:
The Timer2 postscaler (see Section 7.1
“Timer2 Operation”) is not used in the
determination of the PWM frequency.
When the 10-bit time base matches the CCPR1H and
2-bit latch, then the CCP1 pin is cleared (see
Figure 11-3).
11.3.2
PWM DUTY CYCLE
11.3.3
PWM RESOLUTION
The PWM duty cycle is specified by writing a 10-bit
value to multiple registers: CCPR1L register and
CCP1<1:0> bits of the CCP1CON register. The
CCPR1L contains the eight MSbs and the CCP1<1:0>
bits of the CCP1CON register contain the two LSbs.
CCPR1L and CCP1<1:0> bits of the CCP1CON
register can be written to at any time. The duty cycle
value is not latched into CCPR1H until after the period
completes (i.e., a match between PR2 and TMR2
registers occurs). While using the PWM, the CCPR1H
register is read-only.
The resolution determines the number of available duty
cycles for a given period. For example, a 10-bit resolution
will result in 1024 discrete duty cycles, whereas an 8-bit
resolution will result in 256 discrete duty cycles.
The maximum PWM resolution is 10 bits when PR2 is
255. The resolution is a function of the PR2 register
value as shown by Equation 11-4.
EQUATION 11-4: PWM RESOLUTION
log[4(PR2 + 1)]
Equation 11-2 is used to calculate the PWM pulse
width.
Resolution = ----------------------------------------- bits
log(2)
Equation 11-3 is used to calculate the PWM duty cycle
ratio.
Note:
If the pulse width value is greater than the
period the assigned PWM pin(s) will
remain unchanged.
TABLE 11-2: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz)
PWM Frequency
1.22 kHz
4.88 kHz
19.53 kHz
78.12 kHz
156.3 kHz
208.3 kHz
Timer Prescale (1, 4, 16)
PR2 Value
16
0xFF
10
4
1
1
0x3F
8
1
0x1F
7
1
0xFF
10
0xFF
10
0x17
6.6
Maximum Resolution (bits)
TABLE 11-3: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 8 MHz)
PWM Frequency
1.22 kHz
4.90 kHz
19.61 kHz
76.92 kHz
153.85 kHz 200.0 kHz
Timer Prescale (1, 4, 16)
PR2 Value
16
0x65
8
4
0x65
8
1
0x65
8
1
0x19
6
1
0x0C
5
1
0x09
5
Maximum Resolution (bits)
© 2007 Microchip Technology Inc.
DS41202F-page 83
PIC16F684
11.3.4
OPERATION IN SLEEP MODE
11.3.7
SETUP FOR PWM OPERATION
In Sleep mode, the TMR2 register will not increment
and the state of the module will not change. If the CCP1
pin is driving a value, it will continue to drive that value.
When the device wakes up, TMR2 will continue from its
previous state.
The following steps should be taken when configuring
the CCP module for PWM operation:
1. Disable the PWM pin (CCP1) output driver by
setting the associated TRIS bit.
2. Set the PWM period by loading the PR2 register.
3. Configure the CCP module for the PWM mode
by loading the CCP1CON register with the
appropriate values.
11.3.5
CHANGES IN SYSTEM CLOCK
FREQUENCY
The PWM frequency is derived from the system clock
frequency. Any changes in the system clock frequency
will result in changes to the PWM frequency. See
Section 3.0 “Oscillator Module (With Fail-Safe
Clock Monitor)” for additional details.
4. Set the PWM duty cycle by loading the CCPR1L
register and CCP1 bits of the CCP1CON register.
5. Configure and start Timer2:
• Clear the TMR2IF interrupt flag bit of the
PIR1 register.
11.3.6
EFFECTS OF RESET
• Set the Timer2 prescale value by loading the
T2CKPS bits of the T2CON register.
Any Reset will force all ports to Input mode and the
CCP registers to their Reset states.
• Enable Timer2 by setting the TMR2ON bit of
the T2CON register.
6. Enable PWM output after a new PWM cycle has
started:
• Wait until Timer2 overflows (TMR2IF bit of
the PIR1 register is set).
• Enable the CCP1 pin output driver by clearing
the associated TRIS bit.
DS41202F-page 84
© 2007 Microchip Technology Inc.
PIC16F684
The PWM outputs are multiplexed with I/O pins and are
designated P1A, P1B, P1C and P1D. The polarity of the
PWM pins is configurable and is selected by setting the
CCP1M bits in the CCP1CON register appropriately.
11.4 PWM (Enhanced Mode)
The Enhanced PWM Mode can generate a PWM signal
on up to four different output pins with up to 10-bits of
resolution. It can do this through four different PWM
output modes:
Table 11-4 shows the pin assignments for each
Enhanced PWM mode.
• Single PWM
Figure 11-5 shows an example of a simplified block
diagram of the Enhanced PWM module.
• Half-Bridge PWM
• Full-Bridge PWM, Forward mode
• Full-Bridge PWM, Reverse mode
Note:
To prevent the generation of an
incomplete waveform when the PWM is
first enabled, the ECCP module waits until
the start of a new PWM period before
generating a PWM signal.
To select an Enhanced PWM mode, the P1M bits of the
CCP1CON register must be set appropriately.
FIGURE 11-5:
EXAMPLE SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODE
CCP1<1:0>
P1M<1:0>
CCP1M<3:0>
4
Duty Cycle Registers
2
CCPR1L
CCP1/P1A
CCP1/P1A
TRIS
TRIS
TRIS
TRIS
CCPR1H (Slave)
Comparator
P1B
P1B
P1C
Output
Controller
R
S
Q
P1C
(1)
TMR2
P1D
P1D
Comparator
PR2
Clear Timer2,
toggle PWM pin and
latch duty cycle
PWM1CON
Note 1: The 8-bit timer TMR2 register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler to create the 10-bit
time base.
Note 1: The TRIS register value for each PWM output must be configured appropriately.
2: Clearing the CCP1CON register will relinquish ECCP control of all PWM output pins.
3: Any pin not used by an Enhanced PWM mode is available for alternate pin functions
TABLE 11-4: EXAMPLE PIN ASSIGNMENTS FOR VARIOUS PWM ENHANCED MODES
ECCP Mode
P1M
CCP1/P1A
P1B
P1C
P1D
Single
00
10
01
11
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
No
No
No
No
Half-Bridge
Full-Bridge, Forward
Full-Bridge, Reverse
Yes
Yes
Yes
Yes
© 2007 Microchip Technology Inc.
DS41202F-page 85
PIC16F684
FIGURE 11-6:
EXAMPLE PWM (ENHANCED MODE) OUTPUT RELATIONSHIPS (ACTIVE-HIGH
STATE)
PR2+1
Pulse
Width
0
Signal
P1M<1:0>
Period
P1A Modulated
(Single Output)
00
10
Delay(1)
Delay(1)
P1A Modulated
P1B Modulated
P1A Active
(Half-Bridge)
P1B Inactive
(Full-Bridge,
Forward)
01
P1C Inactive
P1D Modulated
P1A Inactive
P1B Modulated
P1C Active
(Full-Bridge,
Reverse)
11
P1D Inactive
Relationships:
•
•
•
Period = 4 * TOSC * (PR2 + 1) * (TMR2 Prescale Value)
Pulse Width = TOSC * (CCPR1L<7:0>:CCP1CON<5:4>) * (TMR2 Prescale Value)
Delay = 4 * TOSC * (PWM1CON<6:0>)
Note 1: Dead-band delay is programmed using the PWM1CON register (Section 11.4.6 “Programmable Dead-Band Delay
mode”).
DS41202F-page 86
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 11-7:
EXAMPLE ENHANCED PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE)
PR2+1
Pulse
Width
0
Signal
P1M<1:0>
Period
P1A Modulated
P1A Modulated
P1B Modulated
P1A Active
(Single Output)
00
10
Delay(1)
Delay(1)
(Half-Bridge)
(Full-Bridge,
Forward)
P1B Inactive
P1C Inactive
P1D Modulated
P1A Inactive
P1B Modulated
P1C Active
01
(Full-Bridge,
Reverse)
11
P1D Inactive
Relationships:
•
•
•
Period = 4 * TOSC * (PR2 + 1) * (TMR2 Prescale Value)
Pulse Width = TOSC * (CCPR1L<7:0>:CCP1CON<5:4>) * (TMR2 Prescale Value)
Delay = 4 * TOSC * (PWM1CON<6:0>)
Note 1: Dead-band delay is programmed using the PWM1CON register (Section 11.4.6 “Programmable Dead-Band Delay
mode”).
© 2007 Microchip Technology Inc.
DS41202F-page 87
PIC16F684
Since the P1A and P1B outputs are multiplexed with
the PORT data latches, the associated TRIS bits must
be cleared to configure P1A and P1B as outputs.
11.4.1
HALF-BRIDGE MODE
In Half-Bridge mode, two pins are used as outputs to
drive push-pull loads. The PWM output signal is output
on the CCP1/P1A pin, while the complementary PWM
output signal is output on the P1B pin (see
Figure 11-16). This mode can be used for half-bridge
applications, as shown in Figure 11-17, or for
full-bridge applications, where four power switches are
being modulated with two PWM signals.
FIGURE 11-8:
EXAMPLE OF
HALF-BRIDGE PWM
OUTPUT
Period
Period
Pulse Width
In Half-Bridge mode, the programmable dead-band delay
can be used to prevent shoot-through current in
half-bridge power devices. The value of the PDC<6:0>
bits of the PWM1CON register sets the number of
instruction cycles before the output is driven active. If the
value is greater than the duty cycle, the corresponding
output remains inactive during the entire cycle. See
Section 11.4.6 “Programmable Dead-Band Delay
mode” for more details of the dead-band delay
operations.
(2)
(2)
P1A
td
td
P1B
(1)
(1)
(1)
td = Dead-Band Delay
Note 1: At this time, the TMR2 register is equal to the
PR2 register.
2: Output signals are shown as active-high.
FIGURE 11-9:
EXAMPLE OF HALF-BRIDGE APPLICATIONS
Standard Half-Bridge Circuit (“Push-Pull”)
FET
Driver
+
-
P1A
Load
FET
Driver
+
-
P1B
Half-Bridge Output Driving a Full-Bridge Circuit
V+
FET
Driver
FET
Driver
P1A
Load
FET
FET
Driver
Driver
P1B
DS41202F-page 88
© 2007 Microchip Technology Inc.
PIC16F684
11.4.2
FULL-BRIDGE MODE
In Full-Bridge mode, all four pins are used as outputs.
An example of full-bridge application is shown in
Figure 11-10.
In the Forward mode, pin CCP1/P1A is driven to its active
state, pin P1D is modulated, while P1B and P1C will be
driven to their inactive state as shown in Figure 11-11.
In the Reverse mode, P1C is driven to its active state,
pin P1B is modulated, while P1A and P1D will be driven
to their inactive state as shown Figure 11-11.
P1A, P1B, P1C and P1D outputs are multiplexed with
the PORT data latches. The associated TRIS bits must
be cleared to configure the P1A, P1B, P1C and P1D
pins as outputs.
FIGURE 11-10:
EXAMPLE OF FULL-BRIDGE APPLICATION
V+
QC
QA
FET
Driver
FET
Driver
P1A
P1B
Load
FET
Driver
FET
Driver
P1C
P1D
QD
QB
V-
© 2007 Microchip Technology Inc.
DS41202F-page 89
PIC16F684
FIGURE 11-11:
EXAMPLE OF FULL-BRIDGE PWM OUTPUT
Forward Mode
Period
(2)
P1A
Pulse Width
(2)
P1B
(2)
P1C
(2)
P1D
(1)
(1)
Reverse Mode
Period
Pulse Width
(2)
P1A
(2)
P1B
(2)
P1C
(2)
P1D
(1)
(1)
Note 1: At this time, the TMR2 register is equal to the PR2 register.
2: Output signal is shown as active-high.
DS41202F-page 90
© 2007 Microchip Technology Inc.
PIC16F684
The Full-Bridge mode does not provide dead-band
delay. As one output is modulated at a time, dead-band
delay is generally not required. There is a situation
where dead-band delay is required. This situation
occurs when both of the following conditions are true:
11.4.2.1
Direction Change in Full-Bridge
Mode
In the Full-Bridge mode, the P1M1 bit in the CCP1CON
register allows users to control the forward/reverse
direction. When the application firmware changes this
direction control bit, the module will change to the new
direction on the next PWM cycle.
1. The direction of the PWM output changes when
the duty cycle of the output is at or near 100%.
2. The turn off time of the power switch, including
the power device and driver circuit, is greater
than the turn on time.
A direction change is initiated in software by changing
the P1M1 bit of the CCP1CON register. The following
sequence occurs four Timer2 cycles prior to the end of
the current PWM period:
Figure 11-13 shows an example of the PWM direction
changing from forward to reverse, at a near 100% duty
cycle. In this example, at time t1, the output P1A and
P1D become inactive, while output P1C becomes
active. Since the turn off time of the power devices is
longer than the turn on time, a shoot-through current
will flow through power devices QC and QD (see
Figure 11-10) for the duration of ‘t’. The same
phenomenon will occur to power devices QA and QB
for PWM direction change from reverse to forward.
• The modulated outputs (P1B and P1D) are placed
in their inactive state.
• The associated unmodulated outputs (P1A and
P1C) are switched to drive in the opposite
direction.
• PWM modulation resumes at the beginning of the
next period.
See Figure 11-12 for an illustration of this sequence.
If changing PWM direction at high duty cycle is required
for an application, two possible solutions for eliminating
the shoot-through current are:
1. Reduce PWM duty cycle for one PWM period
before changing directions.
2. Use switch drivers that can drive the switches off
faster than they can drive them on.
Other options to prevent shoot-through current may
exist.
FIGURE 11-12:
EXAMPLE OF PWM DIRECTION CHANGE
(1)
Period
Period
Signal
P1A (Active-High)
P1B (Active-High)
Pulse Width
P1C (Active-High)
P1D (Active-High)
(2)
Pulse Width
Note 1: The direction bit P1M1 of the CCP1CON register is written any time during the PWM cycle.
2: When changing directions, the P1A and P1C signals switch before the end of the current PWM cycle. The
modulated P1B and P1D signals are inactive at this time. The length of this time is four Timer2 counts.
© 2007 Microchip Technology Inc.
DS41202F-page 91
PIC16F684
FIGURE 11-13:
EXAMPLE OF PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE
Forward Period
Reverse Period
t1
P1A
P1B
DC
P1C
P1D
PW
TON
External Switch C
External Switch D
TOFF
Potential
T = TOFF – TON
Shoot-Through Current
Note 1: All signals are shown as active-high.
2: TON is the turn on delay of power switch QC and its driver.
3: TOFF is the turn off delay of power switch QD and its driver.
11.4.3
START-UP CONSIDERATIONS
When any PWM mode is used, the application
hardware must use the proper external pull-up and/or
pull-down resistors on the PWM output pins.
Note:
When the microcontroller is released from
Reset, all of the I/O pins are in the
high-impedance state. The external cir-
cuits must keep the power switch devices
in the OFF state until the microcontroller
drives the I/O pins with the proper signal
levels or activates the PWM output(s).
The CCP1M<1:0> bits of the CCP1CON register allow
the user to choose whether the PWM output signals are
active-high or active-low for each pair of PWM output pins
(P1A/P1C and P1B/P1D). The PWM output polarities
must be selected before the PWM pin output drivers are
enabled. Changing the polarity configuration while the
PWM pin output drivers are enabled is not recommended
since it may result in damage to the application circuits.
The P1A, P1B, P1C and P1D output latches may not be
in the proper states when the PWM module is
initialized. Enabling the PWM pin output drivers at the
same time as the Enhanced PWM modes may cause
damage to the application circuit. The Enhanced PWM
modes must be enabled in the proper Output mode and
complete a full PWM cycle before enabling the PWM
pin output drivers. The completion of a full PWM cycle
is indicated by the TMR2IF bit of the PIR1 register
being set as the second PWM period begins.
DS41202F-page 92
© 2007 Microchip Technology Inc.
PIC16F684
A shutdown condition is indicated by the ECCPASE
(Auto-Shutdown Event Status) bit of the ECCPAS
register. If the bit is a ‘0’, the PWM pins are operating
normally. If the bit is a ‘1’, the PWM outputs are in the
shutdown state.
11.4.4
ENHANCED PWM
AUTO-SHUTDOWN MODE
The PWM mode supports an Auto-Shutdown mode that
will disable the PWM outputs when an external
shutdown event occurs. Auto-Shutdown mode places
the PWM output pins into a predetermined state. This
mode is used to help prevent the PWM from damaging
the application.
When a shutdown event occurs, two things happen:
The ECCPASE bit is set to ‘1’. The ECCPASE will
remain set until cleared in firmware or an auto-restart
occurs (see Section 11.4.5 “Auto-Restart Mode”).
The auto-shutdown sources are selected using the
ECCPASx bits of the ECCPAS register. A shutdown
event may be generated by:
The enabled PWM pins are asynchronously placed in
their shutdown states. The PWM output pins are
grouped into pairs [P1A/P1C] and [P1B/P1D]. The state
of each pin pair is determined by the PSSAC and
PSSBD bits of the ECCPAS register. Each pin pair may
be placed into one of three states:
• A logic ‘0’ on the INT pin
• Comparator 1
• Comparator 2
• Setting the ECCPASE bit in firmware
• Drive logic ‘1’
• Drive logic ‘0’
• Tri-state (high-impedance)
REGISTER 11-2: ECCPAS: ENHANCED CAPTURE/COMPARE/PWM AUTO-SHUTDOWN
CONTROL REGISTER
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
ECCPASE
ECCPAS2
ECCPAS1
ECCPAS0
PSSAC1
PSSAC0
PSSBD1
PSSBD0
bit 7
bit 0
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
bit 7
ECCPASE: ECCP Auto-Shutdown Event Status bit
1= A shutdown event has occurred; ECCP outputs are in shutdown state
0= ECCP outputs are operating
bit 6-4
ECCPAS<2:0>: ECCP Auto-shutdown Source Select bits
000= Auto-Shutdown is disabled
001= Comparator 1 output change
010= Comparator 2 output change
011= Either Comparator 1 or 2 change
100= VIL on INT pin
101= VIL on INT pin or Comparator 1 change
110= VIL on INT pin or Comparator 2 change
111= VIL on INT pin or Comparator 1 or 2 change
bit 3-2
bit 1-0
PSSACn: Pins P1A and P1C Shutdown State Control bits
00= Drive pins P1A and P1C to ‘0’
01= Drive pins P1A and P1C to ‘1’
1x= Pins P1A and P1C tri-state
PSSBDn: Pins P1B and P1D Shutdown State Control bits
00= Drive pins P1B and P1D to ‘0’
01= Drive pins P1B and P1D to ‘1’
1x= Pins P1B and P1D tri-state
© 2007 Microchip Technology Inc.
DS41202F-page 93
PIC16F684
Note 1: The auto-shutdown condition is
a
level-based signal, not an edge-based
signal. As long as the level is present, the
auto-shutdown will persist.
2: Writing to the ECCPASE bit is disabled
while an auto-shutdown condition
persists.
3: Once the auto-shutdown condition has
been removed and the PWM restarted
(either through firmware or auto-restart)
the PWM signal will always restart at the
beginning of the next PWM period.
FIGURE 11-14:
PWM AUTO-SHUTDOWN WITH FIRMWARE RESTART (PRSEN = 0)
PWM Period
Shutdown Event
ECCPASE bit
PWM Activity
Normal PWM
ECCPASE
Cleared by
Firmware
Start of
Shutdown
Shutdown
PWM
PWM Period
Event Occurs Event Clears
Resumes
11.4.5
AUTO-RESTART MODE
The Enhanced PWM can be configured to automati-
cally restart the PWM signal once the auto-shutdown
condition has been removed. Auto-restart is enabled by
setting the PRSEN bit in the PWM1CON register.
If auto-restart is enabled, the ECCPASE bit will remain
set as long as the auto-shutdown condition is active.
When the auto-shutdown condition is removed, the
ECCPASE bit will be cleared via hardware and normal
operation will resume.
FIGURE 11-15:
PWM AUTO-SHUTDOWN WITH AUTO-RESTART ENABLED (PRSEN = 1)
PWM Period
Shutdown Event
ECCPASE bit
PWM Activity
Normal PWM
Start of
PWM Period
Shutdown
Event Occurs Event Clears
Shutdown
PWM
Resumes
DS41202F-page 94
© 2007 Microchip Technology Inc.
PIC16F684
11.4.6
PROGRAMMABLE DEAD-BAND
DELAY MODE
FIGURE 11-16:
EXAMPLE OF
HALF-BRIDGE PWM
OUTPUT
In half-bridge applications where all power switches are
modulated at the PWM frequency, the power switches
normally require more time to turn off than to turn on. If
both the upper and lower power switches are switched
at the same time (one turned on, and the other turned
off), both switches may be on for a short period of time
until one switch completely turns off. During this brief
interval, a very high current (shoot-through current) will
flow through both power switches, shorting the bridge
supply. To avoid this potentially destructive
shoot-through current from flowing during switching,
turning on either of the power switches is normally
delayed to allow the other switch to completely turn off.
Period
Period
Pulse Width
(2)
(2)
P1A
td
td
P1B
(1)
(1)
(1)
td = Dead-Band Delay
Note 1: At this time, the TMR2 register is equal to the
In Half-Bridge mode,
a
digitally programmable
PR2 register.
dead-band delay is available to avoid shoot-through
current from destroying the bridge power switches. The
delay occurs at the signal transition from the non-active
state to the active state. See Section FIGURE 11-17:
“Example of Half-Bridge Applications” for
illustration. The lower seven bits of the associated
PWM1CON register (Register 11-3) sets the delay
period in terms of microcontroller instruction cycles
(TCY or 4 TOSC).
2: Output signals are shown as active-high.
FIGURE 11-17:
EXAMPLE OF HALF-BRIDGE APPLICATIONS
V+
Standard Half-Bridge Circuit (“Push-Pull”)
FET
Driver
+
V
-
P1A
Load
FET
Driver
+
V
-
P1B
V-
© 2007 Microchip Technology Inc.
DS41202F-page 95
PIC16F684
REGISTER 11-3: PWM1CON: ENHANCED PWM CONTROL REGISTER
R/W-0
R/W-0
PDC6
R/W-0
PDC5
R/W-0
PDC4
R/W-0
PDC3
R/W-0
PDC2
R/W-0
PDC1
R/W-0
PDC0
PRSEN
bit 7
bit 0
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
bit 7
PRSEN: PWM Restart Enable bit
1= Upon auto-shutdown, the ECCPASE bit clears automatically once the shutdown event goes
away; the PWM restarts automatically
0= Upon auto-shutdown, ECCPASE must be cleared in software to restart the PWM
bit 6-0
PDC<6:0>: PWM Delay Count bits
PDCn = Number of FOSC/4 (4 * TOSC) cycles between the scheduled time when a PWM signal
should transition active and the actual time it transitions active
Note 1: Bit resets to ‘0’ with Two-Speed Start-up and LP, XT or HS selected as the Oscillator mode or Fail-Safe
mode is enabled.
TABLE 11-5: SUMMARY OF REGISTERS ASSOCIATED WITH CAPTURE, COMPARE AND PWM
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
CCPR1L
CCPR1H
CCP1CON
CMCON0
CMCON1
ECCPAS
INTCON
PIE1
Capture/Compare/PWM Register 1 Low Byte
Capture/Compare/PWM Register 1 High Byte
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
P1M1
C2OUT
—
P1M0
C1OUT
—
DC1B1
C2INV
—
DC1B0
C1INV
—
CCP1M3 CCP1M2 CCP1M1 CCP1M0 0000 0000 0000 0000
CIS
—
CM2
—
CM1
CM0
0000 0000 0000 0000
T1GSS C2SYNC ---- --10 ---- --10
ECCPASE ECCPAS2 ECCPAS1 ECCPAS0 PSSAC1 PSSAC0 PSSBD1 PSSBD0 0000 0000 0000 0000
GIE
EEIE
EEIF
PEIE
ADIE
ADIF
T0IE
INTE
C2IE
C2IF
RAIE
C1IE
C1IF
T0IF
INTF
RAIF
0000 0000 0000 0000
CCP1IE
CCP1IF
OSFIE
OSFIF
TMR2IE TMR1IE 0000 0000 0000 0000
TMR2IF TMR1IF 0000 0000 0000 0000
1111 1111 1111 1111
PIR1
PR2
Timer2 Module Period Register
PDC6 PDC5
PWM1CON PRSEN
PDC4
PDC3
PDC2
PDC1
PDC0
0000 0000 0000 0000
T1GINV TMR1GE T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON
0000 0000 uuuu uuuu
T1CON
T2CON
TMR1L
TMR1H
TMR2
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
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
Timer2 Module Register
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
0000 0000 0000 0000
TRISA
TRISC
—
—
—
—
TRISA5
TRISC5
TRISA4
TRISC4
TRISA3
TRISC3
TRISA2
TRISA1
TRISA0 --11 1111 --11 1111
TRISC2 TRISC1 TRISC0 --11 1111 --11 1111
Legend: -= Unimplemented locations, read as ‘0’, u= unchanged, x= unknown. Shaded cells are not used by the Capture,
Compare and PWM.
DS41202F-page 96
© 2007 Microchip Technology Inc.
PIC16F684
12.1 Configuration Bits
12.0 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 as shown in Register 12-1.
These bits are mapped in program memory location
2007h.
The PIC16F684 has a host of features intended to
maximize system reliability, minimize cost through
elimination of external components, provide power
saving features and offer code protection.
These features are:
Note:
Address 2007h is beyond the user program
memory space. It belongs to the special
• Reset
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
configuration
(2000h-3FFFh), which can be accessed
only during programming. See
“PIC12F6XX/16F6XX Memory Program-
ming Specification” (DS41204) for more
information.
memory
space
• Watchdog Timer (WDT)
• Oscillator selection
• Sleep
• Code protection
• ID Locations
• In-Circuit Serial Programming
The PIC16F684 has two timers that offer necessary
delays on power-up. One is the Oscillator Start-up
Timer (OST), intended to keep the chip in Reset until
the crystal oscillator is stable. The other is the
Power-up Timer (PWRT), which provides a fixed delay
of 64 ms (nominal) on power-up only, designed to keep
the part in Reset while the power supply stabilizes.
There is also circuitry to reset the device if a brown-out
occurs, which can use the Power-up Timer to provide
at least
a
64 ms Reset. With these three
functions-on-chip, most applications need no external
Reset circuitry.
The Sleep mode is designed to offer a very low-current
Power-Down mode. The user can wake-up from Sleep
through:
• External Reset
• Watchdog Timer Wake-up
• An interrupt
Several oscillator options are also made available to
allow the part to fit the application. The INTOSC option
saves system cost while the LP crystal option saves
power. A set of configuration bits are used to select
various options (see Register 12-1).
© 2007 Microchip Technology Inc.
DS41202F-page 97
PIC16F684
REGISTER 12-1: CONFIG: CONFIGURATION WORD REGISTER
—
—
—
—
FCMEN
IESO
BOREN1
FOSC1
BOREN0
bit 8
bit 15
bit 7
CPD
CP
MCLRE
PWRTE
WDTE
FOSC2
FOSC0
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
P = Programmable’
‘0’ = Bit is cleared
U = Unimplemented bit, read as ‘0’
x = Bit is unknown
bit 15-12
bit 11
Unimplemented: Read as ‘1’
FCMEN: Fail-Safe Clock Monitor Enabled bit
1= Fail-Safe Clock Monitor is enabled
0= Fail-Safe Clock Monitor is disabled
bit 10
IESO: Internal External Switchover bit
1= Internal External Switchover mode is enabled
0= Internal External Switchover mode is disabled
(1)
bit 9-8
BOREN<1:0>: Brown-out Reset Selection bits
11= BOR enabled
10= BOR enabled during operation and disabled in Sleep
01= BOR controlled by SBOREN bit of the PCON register
00= BOR disabled
(2)
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
CPD: Data Code Protection bit
1= Data memory code protection is disabled
0= Data memory code protection is enabled
(3)
CP: Code Protection bit
1= Program memory code protection is disabled
0= Program memory code protection is enabled
(4)
MCLRE: RA3/MCLR pin function select bit
1= RA3/MCLR pin function is MCLR
0= RA3/MCLR pin function is digital input, MCLR internally tied to VDD
PWRTE: Power-up Timer Enable bit
1= PWRT disabled
0= PWRT enabled
WDTE: Watchdog Timer Enable bit
1= WDT enabled
0= WDT disabled and can be enabled by SWDTEN bit of the WDTCON register
FOSC<2:0>: Oscillator Selection bits
111= RC oscillator: CLKOUT function on RA4/OSC2/CLKOUT pin, RC on RA5/OSC1/CLKIN
110= RCIO oscillator: I/O function on RA4/OSC2/CLKOUT pin, RC on RA5/OSC1/CLKIN
101= INTOSC oscillator: CLKOUT function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN
100= INTOSCIO oscillator: I/O function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN
011= EC: I/O function on RA4/OSC2/CLKOUT pin, CLKIN on RA5/OSC1/CLKIN
010= HS oscillator: High-speed crystal/resonator on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN
001= XT oscillator: Crystal/resonator on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN
000= LP oscillator: Low-power crystal on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN
Note 1: Enabling Brown-out Reset does not automatically enable Power-up Timer.
2: The entire data EEPROM will be erased when the code protection is turned off.
3: The entire program memory will be erased when the code protection is turned off.
4: When MCLR is asserted in INTOSC or RC mode, the internal clock oscillator is disabled.
DS41202F-page 98
© 2007 Microchip Technology Inc.
PIC16F684
Some registers are not affected in any Reset condition;
their status is unknown on POR and unchanged in any
other Reset. Most other registers are reset to a “Reset
state” on:
12.2 Calibration Bits
Brown-out Reset (BOR), Power-on Reset (POR) and
8 MHz internal oscillator (HFINTOSC) are factory cali-
brated. These calibration values are stored in fuses
located in the Calibration Word (2009h). The Calibra-
tion Word is not erased when using the specified bulk
erase sequence in the “PIC12F6XX/16F6XX Memory
Programming Specification” (DS41244) and thus, does
not require reprogramming.
• Power-on Reset
• MCLR Reset
• MCLR Reset during Sleep
• WDT Reset
• Brown-out Reset (BOR)
WDT wake-up does not cause register resets in the
same manner as a WDT Reset since wake-up is
viewed as the resumption of normal operation. TO and
PD bits are set or cleared differently in different Reset
situations, as indicated in Table 12-2. Software can use
these bits to determine the nature of the Reset. See
Table 12-4 for a full description of Reset states of all
registers.
12.3 Reset
The PIC16F684 differentiates between various kinds of
Reset:
a) Power-on Reset (POR)
b) WDT Reset during normal operation
c) WDT Reset during Sleep
d) MCLR Reset during normal operation
e) MCLR Reset during Sleep
f) Brown-out Reset (BOR)
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 12-1.
The MCLR Reset path has a noise filter to detect and
ignore small pulses. See Section 15.0 “Electrical
Specifications” for pulse-width specifications.
FIGURE 12-1:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
External
Reset
MCLR/VPP pin
SLEEP
WDT
WDT
Module
Time-out
Reset
VDD Rise
Detect
Power-on Reset
VDD
Brown-out(1)
Reset
BOREN
SBOREN
S
OST/PWRT
OST
10-bit Ripple Counter
Chip_Reset
R
Q
OSC1/
CLKI pin
PWRT
11-bit Ripple Counter
LFINTOSC
Enable PWRT
Enable OST
Note 1: Refer to the Configuration Word register (Register 12-1).
© 2007 Microchip Technology Inc.
DS41202F-page 99
PIC16F684
12.3.1
POWER-ON RESET (POR)
FIGURE 12-2:
RECOMMENDED MCLR
CIRCUIT
The on-chip POR circuit holds the chip in Reset until
VDD has reached a high enough level for proper
operation. To take advantage of the POR, simply
connect the MCLR pin through a resistor to VDD. This
will eliminate external RC components usually needed
to create Power-on Reset. A maximum rise time for
VDD is required. See Section 15.0 “Electrical
Specifications” for details. If the BOR is enabled, the
maximum rise time specification does not apply. The
BOR circuitry will keep the device in Reset until VDD
reaches VBOR (see Section 12.3.4 “Brown-Out Reset
(BOR)”).
VDD
PIC®
MCU
R1
1 kΩ (or greater)
R2
MCLR
100 Ω
(needed with capacitor)
SW1
(optional)
C1
0.1 μF
(optional, not critical)
Note:
The POR circuit does not produce an
internal Reset when VDD declines. To
re-enable the POR, VDD must reach Vss
for a minimum of 100 μs.
When the device starts normal operation (exits the
Reset condition), device operating parameters (i.e.,
voltage, frequency, temperature, etc.) must be met to
ensure proper operation. If these conditions are not
met, the device must be held in Reset until the
operating conditions are met.
12.3.3
POWER-UP TIMER (PWRT)
The Power-up Timer provides a fixed 64 ms (nominal)
time-out on power-up only, from POR or Brown-out
Reset. The Power-up Timer operates from the 31 kHz
LFINTOSC oscillator. For more information, see
Section 3.5 “Internal Clock Modes”. The chip is kept
in Reset as long as PWRT is active. The PWRT delay
allows the VDD to rise to an acceptable level. A
Configuration bit, PWRTE, can disable (if set) or enable
(if cleared or programmed) the Power-up Timer. The
Power-up Timer should be enabled when Brown-out
Reset is enabled, although it is not required.
For additional information, refer to Application Note
AN607, “Power-up Trouble Shooting” (DS00607).
12.3.2
MCLR
PIC16F684 has a noise filter in the MCLR Reset path.
The filter will detect and ignore small pulses.
It should be noted that a WDT Reset does not drive
MCLR pin low.
The Power-up Timer delay will varies from chip-to-chip
due to:
Voltages applied to the MCLR pin that exceed its
specification can result in both MCLR Resets and
excessive current beyond the device specification
during the ESD event. For this reason, Microchip
recommends that the MCLR pin no longer be tied
directly to VDD. The use of an RC network, as shown in
Figure 12-2, is suggested.
• VDD variation
• Temperature variation
• Process variation
See DC parameters for details (Section 15.0
“Electrical Specifications”).
An internal MCLR option is enabled by clearing the
MCLRE bit in the Configuration Word register. When
MCLRE = 0, the Reset signal to the chip is generated
internally. When the MCLRE = 1, the RA3/MCLR pin
becomes an external Reset input. In this mode, the
RA3/MCLR pin has a weak pull-up to VDD.
Note:
Voltage spikes below VSS at the MCLR
pin, inducing currents greater than 80 mA,
may cause latch-up. Thus, a series resis-
tor of 50-100 Ω should be used when
applying a “low” level to the MCLR pin,
rather than pulling this pin directly to VSS.
DS41202F-page 100
© 2007 Microchip Technology Inc.
PIC16F684
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 re-initialized. Once VDD
rises above VBOR, the Power-up Timer will execute a
64 ms Reset.
12.3.4
BROWN-OUT RESET (BOR)
The BOREN0 and BOREN1 bits in the Configuration
Word register select one of four BOR modes. Two
modes have been added to allow software or hardware
control of the BOR enable. When BOREN<1:0> = 01,
the SBOREN bit of the PCON register enables/disables
the BOR, allowing it to be controlled in software. By
selecting BOREN<1:0> = 10, the BOR is automatically
disabled in Sleep to conserve power and enabled on
wake-up. In this mode, the SBOREN bit is disabled.
See Register 12-1 for the Configuration Word
definition.
12.3.5
BOR CALIBRATION
The PIC16F684 stores the BOR calibration values in
fuses located in the Calibration Word register (2008h).
The Calibration Word register is not erased when using
the specified bulk erase sequence in the
“PIC12F6XX/16F6XX Memory Programming Specifi-
cation” (DS41204) and thus, does not require
reprogramming.
A brown-out occurs when VDD falls below VBOR for
greater than parameter TBOR (see Section 15.0
“Electrical Specifications”). The brown-out condition
will reset the device. This will occur regardless of VDD
slew rate. A Brown-out Reset may not occur if VDD falls
below VBOR for less than parameter TBOR.
Note:
Address 2008h is beyond the user pro-
gram memory space. It belongs to the
special configuration memory space
(2000h-3FFFh), which can be accessed
only
during
programming.
See
On any Reset (Power-on, Brown-out Reset, Watchdog
Timer, etc.), the chip will remain in Reset until VDD rises
above VBOR (see Figure 12-3). If enabled, the
Power-up Timer will be invoked by the Reset and keep
the chip in Reset an additional 64 ms.
“PIC12F6XX/16F6XX Memory Program-
ming Specification” (DS41204) for more
information.
Note:
The Power-up Timer is enabled by the
PWRTE bit in the Configuration Word
register.
FIGURE 12-3:
BROWN-OUT SITUATIONS
VDD
VBOR
Internal
Reset
(1)
64 ms
VDD
VBOR
Internal
Reset
< 64 ms
(1)
64 ms
VDD
VBOR
Internal
Reset
(1)
64 ms
Note 1: 64 ms delay only if PWRTE bit is programmed to ‘0’.
© 2007 Microchip Technology Inc.
DS41202F-page 101
PIC16F684
12.3.6
TIME-OUT SEQUENCE
12.3.7
POWER CONTROL (PCON)
REGISTER
On power-up, the time-out sequence is as follows:
• PWRT time-out is invoked after POR has expired.
The Power Control register PCON (address 8Eh) has
two Status bits to indicate what type of Reset occurred
last.
• OST is activated after the PWRT time-out has
expired.
Bit 0 is BOR (Brown-out). BOR is unknown on
Power-on Reset. It must then be set by the user and
checked on subsequent Resets to see if BOR = 0,
indicating that a Brown-out has occurred. The BOR
Status bit is a “don’t care” and is not necessarily
predictable if the brown-out circuit is disabled
The total time-out will vary based on oscillator
configuration and PWRTE bit status. For example, in EC
mode with PWRTE bit erased (PWRT disabled), there
will be no time-out at all. Figure 12-4, Figure 12-5 and
Figure 12-6 depict time-out sequences. The device can
execute code from the INTOSC while OST is active by
enabling Two-Speed Start-up or Fail-Safe Monitor (see
Section 3.7.2 “Two-speed Start-up Sequence” and
Section 3.8 “Fail-Safe Clock Monitor”).
(BOREN<1:0>
register).
= 00 in the Configuration Word
Bit 1 is POR (Power-on Reset). It is a ‘0’ on Power-on
Reset and unaffected otherwise. The user must write a
‘1’ to this bit following a Power-on Reset. On a subse-
quent Reset, if POR is ‘0’, it will indicate that a
Power-on Reset has occurred (i.e., VDD may have
gone too low).
Since the time-outs occur from the POR pulse, if MCLR
is kept low long enough, the time-outs will expire. Then,
bringing MCLR high will begin execution immediately
(see Figure 12-5). This is useful for testing purposes or
to synchronize more than one PIC16F684 device
operating in parallel.
For more information, see Section 4.2.4 “Ultra
Low-Power
“Brown-Out Reset (BOR)”.
Wake-up”
and
Section 12.3.4
Table 12-5 shows the Reset conditions for some
special registers, while Table 12-4 shows the Reset
conditions for all the registers.
TABLE 12-1: TIME-OUT IN VARIOUS SITUATIONS
Power-up
Brown-out Reset
Wake-up from
Sleep
Oscillator Configuration
PWRTE = 0
PWRTE = 1
PWRTE = 0
PWRTE = 1
1024 • TOSC
XT, HS, LP
TPWRT + 1024 •
TOSC
1024 • TOSC
TPWRT + 1024 •
TOSC
1024 • TOSC
—
RC, EC, INTOSC
TPWRT
—
TPWRT
—
TABLE 12-2: STATUS/PCON BITS AND THEIR SIGNIFICANCE
POR
BOR
TO
PD
Condition
0
u
u
u
x
0
u
u
1
1
0
0
1
1
u
0
Power-on Reset
Brown-out Reset
WDT Reset
WDT Wake-up
u
u
u
u
u
1
u
0
MCLR Reset during normal operation
MCLR Reset during Sleep
Legend: u= unchanged, x= unknown
TABLE 12-3: SUMMARY OF REGISTERS ASSOCIATED WITH BROWN-OUT RESET
Value on:
Value on
all other
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
POR, BOR
Resets(1)
PCON
—
—
ULPWUE SBOREN
RP0 TO
—
—
Z
POR
DC
BOR --01 --qq --0u --uu
0001 1xxx 000q quuu
STATUS
IRP
RP1
PD
C
Legend: u= unchanged, x= unknown, – = unimplemented bit, reads as ‘0’, q= value depends on condition.
Shaded cells are not used by BOR.
Note 1: Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
DS41202F-page 102
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 12-4:
TIME-OUT SEQUENCE ON POWER-UP (DELAYED MCLR): CASE 1
VDD
MCLR
Internal POR
TPWRT
PWRT Time-out
OST Time-out
Internal Reset
TOST
FIGURE 12-5:
TIME-OUT SEQUENCE ON POWER-UP (DELAYED MCLR): CASE 2
VDD
MCLR
Internal POR
TPWRT
PWRT Time-out
OST Time-out
Internal Reset
TOST
FIGURE 12-6:
TIME-OUT SEQUENCE ON POWER-UP (MCLR WITH VDD)
VDD
MCLR
Internal POR
TPWRT
PWRT Time-out
OST Time-out
Internal Reset
TOST
© 2007 Microchip Technology Inc.
DS41202F-page 103
PIC16F684
TABLE 12-4: INITIALIZATION CONDITION FOR REGISTERS
Wake-up from Sleep through
Interrupt
Wake-up from Sleep through
WDT Time-out
MCLR Reset
Power-on
Register
Address
WDT Reset
Reset
Brown-out Reset(1)
W
—
00h/80h
01h
xxxx xxxx
xxxx xxxx
xxxx xxxx
0000 0000
0001 1xxx
xxxx xxxx
--x0 x000
--xx 0000
---0 0000
0000 0000
0000 0000
xxxx xxxx
xxxx xxxx
0000 0000
0000 0000
-000 0000
xxxx xxxx
xxxx xxxx
0000 0000
0000 0000
0000 0000
---0 1000
0000 0000
---- --10
xxxx xxxx
00-0 0000
1111 1111
--11 1111
--11 1111
0000 0000
--01 --0x
-110 x000
uuuu uuuu
xxxx xxxx
uuuu uuuu
0000 0000
000q quuu(4)
uuuu uuuu
--u0 u000
--uu 0000
---0 0000
0000 0000
0000 0000
uuuu uuuu
uuuu uuuu
uuuu uuuu
0000 0000
-000 0000
uuuu uuuu
uuuu uuuu
0000 0000
0000 0000
0000 0000
---0 1000
0000 0000
---- --10
uuuu uuuu
00-0 0000
1111 1111
--11 1111
--11 1111
0000 0000
--0u --uq(1, 5)
-110 q000
uuuu uuuu
uuuu uuuu
uuuu uuuu
PC + 1(3)
INDF
TMR0
PCL
02h/82h
03h/83h
04h/84h
05h
STATUS
uuuq quuu(4)
uuuu uuuu
--uu uuuu
--uu uuuu
---u uuuu
uuuu uuuu(2)
uuuu uuuu(2)
uuuu uuuu
uuuu uuuu
-uuu uuuu
uuuu uuuu
-uuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
---u uuuu
uuuu uuuu
---- --uu
uuuu uuuu
uu-u uuuu
uuuu uuuu
--uu uuuu
--uu uuuu
uuuu uuuu
--uu --uu
-uuu uuuu
FSR
PORTA(6)
PORTC(6)
PCLATH
INTCON
PIR1
07h
0Ah/8Ah
0Bh/8Bh
0Ch
TMR1L
0Eh
TMR1H
T1CON
TMR2
0Fh
10h
11h
T2CON
CCPR1L
CCPR1H
CCP1CON
PWM1CON
ECCPAS
WDTCON
CMCON0
CMCON1
ADRESH
ADCON0
OPTION_REG
TRISA
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
1Eh
1Fh
81h
85h
TRISC
87h
PIE1
8Ch
PCON
8Eh
OSCCON
8Fh
Legend: u= unchanged, x= unknown, – = unimplemented bit, reads as ‘0’, q= value depends on condition.
Note 1: If VDD goes too low, Power-on Reset will be activated and registers will be affected differently.
2: One or more bits in INTCON and/or PIR1 will be affected (to cause wake-up).
3: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt
vector (0004h).
4: See Table 12-5 for Reset value for specific condition.
5: If Reset was due to brown-out, then bit 0 = 0. All other Resets will cause bit 0 = u.
6: Port pins with analog functions controlled by the ANSEL register will read ‘0’ immediately after a Reset
even though the data latches are either undefined (POR) or unchanged (other Resets).
DS41202F-page 104
© 2007 Microchip Technology Inc.
PIC16F684
TABLE 12-4: INITIALIZATION CONDITION FOR REGISTERS (CONTINUED)
Wake-up from Sleep through
Interrupt
Wake-up from Sleep through
WDT Time-out (Continued)
MCLR Reset
Power-on
Reset
Register
Address
WDT Reset (Continued)
Brown-out Reset(1)
OSCTUNE
ANSEL
PR2
90h
91h
92h
95h
96h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
9Fh
---0 0000
1111 1111
1111 1111
--11 -111
--00 0000
0-0- 0000
0000 0000
0000 0000
---- x000
---- ----
xxxx xxxx
-000 ----
---u uuuu
1111 1111
1111 1111
--11 -111
--00 0000
0-0- 0000
0000 0000
0000 0000
---- q000
---- ----
uuuu uuuu
-000 ----
---u uuuu
uuuu uuuu
1111 1111
uuuu uuuu
--uu uuuu
u-u- uuuu
uuuu uuuu
uuuu uuuu
---- uuuu
---- ----
uuuu uuuu
-uuu ----
WPUA
IOCA
VRCON
EEDAT
EEADR
EECON1
EECON2
ADRESL
ADCON1
Legend: u= unchanged, x= unknown, – = unimplemented bit, reads as ‘0’, q= value depends on condition.
Note 1: If VDD goes too low, Power-on Reset will be activated and registers will be affected differently.
2: One or more bits in INTCON and/or PIR1 will be affected (to cause wake-up).
3: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt
vector (0004h).
4: See Table 12-5 for Reset value for specific condition.
5: If Reset was due to brown-out, then bit 0 = 0. All other Resets will cause bit 0 = u.
6: Port pins with analog functions controlled by the ANSEL register will read ‘0’ immediately after a Reset
even though the data latches are either undefined (POR) or unchanged (other Resets).
TABLE 12-5: INITIALIZATION CONDITION FOR SPECIAL REGISTERS
Program
Counter
Status
Register
PCON
Register
Condition
Power-on Reset
000h
000h
0001 1xxx
000u uuuu
--01 --0x
--0u --uu
MCLR Reset during normal operation
MCLR Reset during Sleep
WDT Reset
000h
000h
0001 0uuu
0000 uuuu
uuu0 0uuu
0001 1uuu
uuu1 0uuu
--0u --uu
--0u --uu
--uu --uu
--01 --u0
--uu --uu
WDT Wake-up
PC + 1
000h
PC + 1(1)
Brown-out Reset
Interrupt Wake-up from Sleep
Legend: u= unchanged, x= unknown, – = unimplemented bit, reads as ‘0’.
Note 1: When the wake-up is due to an interrupt and Global Interrupt Enable bit, GIE, is set, the PC is loaded with
the interrupt vector (0004h) after execution of PC + 1.
© 2007 Microchip Technology Inc.
DS41202F-page 105
PIC16F684
For external interrupt events, such as the INT pin or
PORTA change interrupt, the interrupt latency will be
three or four instruction cycles. The exact latency
depends upon when the interrupt event occurs (see
Figure 12-8). The latency is the same for one or
two-cycle instructions. Once in the Interrupt Service
Routine, the source(s) of the interrupt can be
determined by polling the interrupt flag bits. The
interrupt flag bit(s) must be cleared in software before
re-enabling interrupts to avoid multiple interrupt
requests.
12.4 Interrupts
The PIC16F684 has 11 sources of interrupt:
• External Interrupt RA2/INT
• Timer0 Overflow Interrupt
• PORTA Change Interrupts
• 2 Comparator Interrupts
• A/D Interrupt
• Timer1 Overflow Interrupt
• Timer2 Match Interrupt
• EEPROM Data Write Interrupt
• Fail-Safe Clock Monitor Interrupt
• Enhanced CCP Interrupt
Note 1: Individual interrupt flag bits are set,
regardless of the status of their
corresponding mask bit or the GIE bit.
2: When an instruction that clears the GIE
bit is executed, any interrupts that were
pending for execution in the next cycle
are ignored. The interrupts, which were
ignored, are still pending to be serviced
when the GIE bit is set again.
The Interrupt Control register (INTCON) and Peripheral
Interrupt Request Register 1 (PIR1) record individual
interrupt requests in flag bits. The INTCON register
also has individual and global interrupt enable bits.
The Global Interrupt Enable bit, GIE of the INTCON
register, enables (if set) all unmasked interrupts, or
disables (if cleared) all interrupts. Individual interrupts
can be disabled through their corresponding enable
bits in the INTCON register and PIE1 register. GIE is
cleared on Reset.
For additional information on Timer1, Timer2,
comparators, ADC, data EEPROM or Enhanced CCP
modules, refer to the respective peripheral section.
12.4.1
RA2/INT INTERRUPT
When an interrupt is serviced, the following actions
occur automatically:
The external interrupt on the RA2/INT pin is
edge-triggered; either on the rising edge if the INTEDG
bit of the OPTION register is set, or the falling edge, if
the INTEDG bit is clear. When a valid edge appears on
the RA2/INT pin, the INTF bit of the INTCON register is
set. This interrupt can be disabled by clearing the INTE
control bit of the INTCON register. The INTF bit must
be cleared by software in the Interrupt Service Routine
before re-enabling this interrupt. The RA2/INT interrupt
can wake-up the processor from Sleep, if the INTE bit
was set prior to going into Sleep. See Section 12.7
“Power-Down Mode (Sleep)” for details on Sleep and
Figure 12-10 for timing of wake-up from Sleep through
RA2/INT interrupt.
• The GIE is cleared to disable any further interrupt.
• The return address is pushed onto the stack.
• The PC is loaded with 0004h.
The Return from Interrupt instruction, RETFIE, exits
the interrupt routine, as well as sets the GIE bit, which
re-enables unmasked interrupts.
The following interrupt flags are contained in the
INTCON register:
• INT Pin Interrupt
• PORTA Change Interrupt
• Timer0 Overflow Interrupt
Note:
The ANSEL and CMCON0 registers must
be initialized to configure an analog
channel as a digital input. Pins configured
as analog inputs will read ‘0’ and cannot
generate an interrupt.
The peripheral interrupt flags are contained in the PIR1
register. The corresponding interrupt enable bit is
contained in the PIE1 register.
The following interrupt flags are contained in the PIR1
register:
• EEPROM Data Write Interrupt
• A/D Interrupt
• 2 Comparator Interrupts
• Timer1 Overflow Interrupt
• Timer2 Match Interrupt
• Fail-Safe Clock Monitor Interrupt
• Enhanced CCP Interrupt
DS41202F-page 106
© 2007 Microchip Technology Inc.
PIC16F684
12.4.2
TIMER0 INTERRUPT
12.4.3
PORTA INTERRUPT-ON-CHANGE
An overflow (FFh → 00h) in the TMR0 register will set
the T0IF bit of the INTCON register. The interrupt can
be enabled/disabled by setting/clearing T0IE bit of the
INTCON register. See Section 5.0 “Timer0 Module”
for operation of the Timer0 module.
An input change on PORTA sets the RAIF bit of the
INTCON register. The interrupt can be
enabled/disabled by setting/clearing the RAIE bit of the
INTCON register. Plus, individual pins can be
configured through the IOCA register.
Note:
If a change on the I/O pin should occur
when any PORTA operation is being
executed, then the RAIF interrupt flag may
not get set.
FIGURE 12-7:
INTERRUPT LOGIC
IOC-RA0
IOCA0
IOC-RA1
IOCA1
IOC-RA2
IOCA2
IOC-RA3
IOCA3
IOC-RA4
IOCA4
IOC-RA5
IOCA5
(1)
Wake-up (If in Sleep mode)
T0IF
T0IE
TMR2IF
TMR2IE
INTF
INTE
RAIF
Interrupt to CPU
TMR1IF
TMR1IE
RAIE
C1IF
C1IE
PEIE
GIE
C2IF
C2IE
ADIF
ADIE
EEIF
EEIE
Note 1: Some peripherals depend upon the system clock for
operation. Since the system clock is suspended during Sleep, only
those peripherals which do not depend upon the system clock will wake
the part from Sleep. See Section 12.7.1 “Wake-up from Sleep”.
OSFIF
OSFIE
CCP1IF
CCP1IE
© 2007 Microchip Technology Inc.
DS41202F-page 107
PIC16F684
FIGURE 12-8:
INT PIN INTERRUPT TIMING
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
(3)
CLKOUT
(4)
INT pin
(1)
(1)
(2)
(5)
Interrupt Latency
INTF flag
(INTCON reg.)
GIE bit
(INTCON reg.)
INSTRUCTION FLOW
PC
PC + 1
—
0004h
0005h
PC
Inst (PC)
PC + 1
Instruction
Fetched
Inst (PC + 1)
Inst (0004h)
Inst (0005h)
Inst (0004h)
Instruction
Executed
Dummy Cycle
Dummy Cycle
Inst (PC)
Inst (PC – 1)
Note 1: INTF flag is sampled here (every Q1).
2: Asynchronous interrupt latency = 3-4 TCY. Synchronous latency = 3 TCY, where TCY = instruction cycle time. Latency
is the same whether Inst (PC) is a single cycle or a 2-cycle instruction.
3: CLKOUT is available only in INTOSC and RC Oscillator modes.
4: For minimum width of INT pulse, refer to AC specifications in Section 15.0 “Electrical Specifications”.
5: INTF is enabled to be set any time during the Q4-Q1 cycles.
TABLE 12-6: SUMMARY OF REGISTERS ASSOCIATED WITH INTERRUPTS
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
IOCA
PIR1
GIE
—
PEIE
—
T0IE
INTE
RAIE
T0IF
INTF
RAIF
0000 0000 0000 0000
IOCA5 IOCA4 IOCA3 IOCA2
IOCA1
IOCA0 --00 0000 --00 0000
EEIF
EEIE
ADIF CCP1IF C2IF
ADIE CCP1IE C2IE
C1IF OSFIF TMR2IF TMR1IF 0000 0000 0000 0000
C1IE OSFIE TMR2IE TMR1IE 0000 0000 0000 0000
PIE1
Legend: x= unknown, u= unchanged, – = unimplemented read as ‘0’, q= value depends upon condition.
Shaded cells are not used by the interrupt module.
DS41202F-page 108
© 2007 Microchip Technology Inc.
PIC16F684
12.5 Context Saving During Interrupts
During an interrupt, only the return PC value is saved
on the stack. Typically, users may wish to save key
registers during an interrupt (e.g., W and STATUS
registers). This must be implemented in software.
Temporary
holding
registers
W_TEMP
and
STATUS_TEMP should be placed in the last 16 bytes
of GPR (see Figure 2-2). These 16 locations are
common to all banks and do not require banking. This
makes context save and restore operations simpler.
The code shown in Example 12-1 can be used to:
• Store the W register
• Store the STATUS register
• Execute the ISR code
• Restore the Status (and Bank Select Bit register)
• Restore the W register
Note:
The PIC16F684 does not require saving
the PCLATH. However, if computed
GOTOs are used in both the ISR and the
main code, the PCLATH must be saved
and restored in the ISR.
EXAMPLE 12-1:
SAVING STATUS AND W REGISTERS IN RAM
MOVWF
SWAPF
W_TEMP
STATUS,W
;Copy W to TEMP register
;Swap status to be saved into W
;Swaps are used because they do not affect the status bits
;Save status to bank zero STATUS_TEMP register
MOVWF
:
STATUS_TEMP
:(ISR)
:
;Insert user code here
SWAPF
STATUS_TEMP,W
;Swap STATUS_TEMP register into W
;(sets bank to original state)
;Move W into STATUS register
;Swap W_TEMP
MOVWF
SWAPF
SWAPF
STATUS
W_TEMP,F
W_TEMP,W
;Swap W_TEMP into W
© 2007 Microchip Technology Inc.
DS41202F-page 109
PIC16F684
12.6.2
WDT CONTROL
12.6 Watchdog Timer (WDT)
The WDTE bit is located in the Configuration Word
register. When set, the WDT runs continuously.
The WDT has the following features:
• Operates from the LFINTOSC (31 kHz)
• Contains a 16-bit prescaler
When the WDTE bit in the Configuration Word register
is set, the SWDTEN bit of the WDTCON register has no
effect. If WDTE is clear, then the SWDTEN bit can be
used to enable and disable the WDT. Setting the bit will
enable it and clearing the bit will disable it.
• Shares an 8-bit prescaler with Timer0
• Time-out period is from 1 ms to 268 seconds
• Configuration bit and software controlled
WDT is cleared under certain conditions described in
Table 12-7.
The PSA and PS<2:0> bits of the OPTION register
have the same function as in previous versions of the
PIC16F684
Family
of
microcontrollers.
See
12.6.1
WDT OSCILLATOR
Section 5.0 “Timer0 Module” for more information.
The WDT derives its time base from the 31 kHz
LFINTOSC. The LTS bit of the OSCCON register does
not reflect that the LFINTOSC is enabled.
The value of WDTCON is ‘---0 1000’ on all Resets.
This gives a nominal time base of 17 ms.
Note:
When the Oscillator Start-up Timer (OST)
is invoked, the WDT is held in Reset,
because the WDT Ripple Counter is used
by the OST to perform the oscillator delay
count. When the OST count has expired,
the WDT will begin counting (if enabled).
FIGURE 12-9:
WATCHDOG TIMER BLOCK DIAGRAM
0
1
From Timer0 Clock Source
Prescaler(1)
16-bit WDT Prescaler
8
PSA
PS<2:0>
31 kHz
LFINTOSC Clock
WDTPS<3:0>
To Timer0
1
0
PSA
WDTE from the Configuration Word Register
SWDTEN from WDTCON
WDT Time-out
Note 1: This is the shared Timer0/WDT prescaler. See Section 5.0 “Timer0 Module” for more information.
TABLE 12-7: WDT STATUS
Conditions
WDT
WDTE = 0
CLRWDTCommand
Oscillator Fail Detected
Cleared
Exit Sleep + System Clock = T1OSC, EXTRC, INTRC, EXTCLK
Exit Sleep + System Clock = XT, HS, LP
Cleared until the end of OST
DS41202F-page 110
© 2007 Microchip Technology Inc.
PIC16F684
REGISTER 12-2: WDTCON: WATCHDOG TIMER CONTROL REGISTER
U-0
—
U-0
—
U-0
—
R/W-0
R/W-1
R/W-0
R/W-0
R/W-0
WDTPS3
WDTPS2
WDTPS1
WDTPS0
SWDTEN
bit 7
bit 0
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
bit 7-5
bit 4-1
Unimplemented: Read as ‘0’
WDTPS<3:0>: Watchdog Timer Period Select bits
Bit Value = Prescale Rate
0000 = 1:32
0001 = 1:64
0010 = 1:128
0011 = 1:256
0100 = 1:512 (Reset value)
0101 = 1:1024
0110 = 1:2048
0111 = 1:4096
1000 = 1:8192
1001 = 1:16384
1010 = 1:32768
1011 = 1:65536
1100 = Reserved
1101 = Reserved
1110 = Reserved
1111 = Reserved
bit 0
SWDTEN: Software Enable or Disable the Watchdog Timer(1)
1= WDT is turned on
0= WDT is turned off (Reset value)
Note 1: If WDTE Configuration bit = 1, then WDT is always enabled, irrespective of this control bit. If WDTE
Configuration bit = 0, then it is possible to turn WDT on/off with this control bit.
TABLE 12-8: SUMMARY OF REGISTERS ASSOCIATED WITH WATCHDOG TIMER
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
WDTCON
—
—
—
WDTPS3 WDTPS2 WSTPS1 WDTPS0 SWDTEN ---0 1000 ---0 1000
OPTION_REG RAPU INTEDG T0CS
T0SE
MCLRE PWRTE WDTE
Shaded cells are not used by the Watchdog Timer.
PSA
PS2
PS1
PS0
1111 1111 1111 1111
CONFIG
CPD
CP
FOSC2 FOSC1
FOSC0
—
—
Legend:
Note 1: See Register 12-1 for operation of all Configuration Word register bits.
© 2007 Microchip Technology Inc.
DS41202F-page 111
PIC16F684
When the SLEEPinstruction is being executed, the next
instruction (PC + 1) is prefetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be set (enabled). Wake-up
occurs regardless of the state of the GIE bit. If the GIE
bit is clear (disabled), the device continues execution at
the instruction after the SLEEPinstruction. If the GIE bit
is set (enabled), the device executes the instruction
after the SLEEPinstruction, then branches to the inter-
rupt address (0004h). In cases where the execution of
the instruction following SLEEP is not desirable, the
user should have a NOPafter the SLEEPinstruction.
12.7 Power-Down Mode (Sleep)
The Power-down mode is entered by executing a
SLEEPinstruction.
If the Watchdog Timer is enabled:
• WDT will be cleared but keeps running.
• PD bit in the STATUS register is cleared.
• TO bit is set.
• Oscillator driver is turned off.
• I/O ports maintain the status they had before SLEEP
was executed (driving high, low or high-impedance).
Note:
If the global interrupts are disabled (GIE is
cleared) and any interrupt source has both
its interrupt enable bit and the correspond-
ing interrupt flag bits set, the device will
immediately wake-up from Sleep.
For lowest current consumption in this mode, all I/O pins
should be either at VDD or VSS, with no external circuitry
drawing current from the I/O pin and the comparators
and CVREF should be disabled. I/O pins that are
high-impedance inputs should be pulled high or low
externally to avoid switching currents caused by floating
inputs. The T0CKI input should also be at VDD or VSS for
lowest current consumption. The contribution from
on-chip pull-ups on PORTA should be considered.
The WDT is cleared when the device wakes up from
Sleep, regardless of the source of wake-up.
12.7.2
WAKE-UP USING INTERRUPTS
The MCLR pin must be at a logic high level.
When global interrupts are disabled (GIE cleared) and
any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
Note:
It should be noted that a Reset generated
by a WDT time-out does not drive MCLR
pin low.
• If the interrupt occurs before the execution of a
SLEEPinstruction, the SLEEPinstruction will
complete as a NOP. Therefore, the WDT and WDT
prescaler and postscaler (if enabled) will not be
cleared, the TO bit will not be set and the PD bit
will not be cleared.
12.7.1
WAKE-UP FROM SLEEP
The device can wake-up from Sleep through one of the
following events:
1. External Reset input on MCLR pin.
• If the interrupt occurs during or after the
execution of a SLEEPinstruction, the device will
Immediately wake-up from Sleep. The SLEEP
instruction is executed. Therefore, the WDT and
WDT prescaler and postscaler (if enabled) will be
cleared, the TO bit will be set and the PD bit will
be cleared.
2. Watchdog Timer wake-up (if WDT was
enabled).
3. Interrupt from RA2/INT pin, PORTA change or a
peripheral interrupt.
The first event will cause a device Reset. The two latter
events are considered a continuation of program
execution. The TO and PD bits in the STATUS register
can be used to determine the cause of a device Reset.
The PD bit, which is set on power-up, is cleared when
Sleep is invoked. TO bit is cleared if WDT wake-up
occurred.
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEPinstruction completes. To
determine whether a SLEEPinstruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.
The following peripheral interrupts can wake the device
from Sleep:
To ensure that the WDT is cleared, a CLRWDTinstruction
should be executed before a SLEEP instruction. See
Figure 12-10 for more details.
1. Timer1 interrupt. Timer1 must be operating as
an asynchronous counter.
2. ECCP Capture mode interrupt.
3. A/D conversion (when A/D clock source is FRC).
4. EEPROM write operation completion.
5. Comparator output changes state.
6. Interrupt-on-change.
7. External Interrupt from INT pin.
Other peripherals cannot generate interrupts since
during Sleep, no on-chip clocks are present.
DS41202F-page 112
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 12-10:
WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
CLKOUT(4)
INT pin
(2)
TOST
INTF flag
(INTCON reg.)
Interrupt Latency(3)
GIE bit
(INTCON reg.)
Processor in
Sleep
Instruction Flow
PC
PC
PC + 1
PC + 2
PC + 2
PC + 2
0004h
0005h
Instruction
Fetched
Inst(0004h)
Inst(PC + 1)
Inst(PC + 2)
Inst(0005h)
Inst(PC) = Sleep
Instruction
Executed
Dummy Cycle
Dummy Cycle
Sleep
Inst(PC + 1)
Inst(PC – 1)
Inst(0004h)
Note 1: XT, HS or LP Oscillator mode assumed.
2: TOST = 1024 TOSC (drawing not to scale). This delay does not apply to EC, INTOSC and RC Oscillator modes.
3: GIE = ‘1’ assumed. In this case after wake-up, the processor jumps to 0004h. If GIE = ‘0’, execution will continue in-line.
4: CLKOUT is not available in XT, HS, LP or EC Oscillator modes, but shown here for timing reference.
12.8 Code Protection
If the code protection bit(s) have not been
programmed, the on-chip program memory can be
read out using ICSP™ for verification purposes.
Note:
The entire data EEPROM and Flash pro-
gram memory will be erased when the
code protection is turned off. See the
“PIC12F6XX/16F6XX Memory
Programming Specification” (DS41204)
for more information.
12.9 ID Locations
Four memory locations (2000h-2003h) are designated
as ID locations where the user can store checksum or
other code identification numbers. These locations are
not accessible during normal execution but are
readable and writable during Program/Verify mode.
Only the Least Significant 7 bits of the ID locations are
used.
© 2007 Microchip Technology Inc.
DS41202F-page 113
PIC16F684
12.10 In-Circuit Serial Programming
12.11 In-Circuit Debugger
The PIC16F684 microcontrollers can be serially
programmed while in the end application circuit. This is
simply done with five connections for:
Since in-circuit debugging requires access to three
pins, MPLAB® ICD 2 development with a 14-pin device
is not practical. A special 20-pin PIC16F684 ICD device
is used with MPLAB ICD 2 to provide separate clock,
data and MCLR pins and frees all normally available
pins to the user.
• clock
• data
• power
A special debugging adapter allows the ICD device to
be used in place of a PIC16F684 device. The
debugging adapter is the only source of the ICD device.
• ground
• programming voltage
This allows customers to manufacture boards with
unprogrammed devices and then program the micro-
controller just before shipping the product. This also
allows the most recent firmware or a custom firmware
to be programmed.
When the ICD pin on the PIC16F684 ICD device is held
low, the In-Circuit Debugger functionality is enabled.
This function allows simple debugging functions when
used with MPLAB ICD 2. When the microcontroller has
this feature enabled, some of the resources are not
available for general use. Table 12-9 shows which
features are consumed by the background debugger.
The device is placed into a Program/Verify mode by
holding the RA0 and RA1 pins low, while raising the
MCLR (VPP) pin from VIL to VIHH. See the
“PIC12F6XX/16F6XX
Memory
Programming
TABLE 12-9: DEBUGGER RESOURCES
Specification” (DS41204) for more information. RA0
becomes the programming data and RA1 becomes the
programming clock. Both RA0 and RA1 are Schmitt
Trigger inputs in Program/Verify mode.
Resource
Description
I/O pins
Stack
ICDCLK, ICDDATA
1 level
A typical In-Circuit Serial Programming connection is
shown in Figure 12-11.
Program Memory Address 0h must be NOP
700h-7FFh
For more information, see “MPLAB® ICD 2 In-Circuit
Debugger User’s Guide” (DS51331), available on
Microchip’s web site (www.microchip.com).
FIGURE 12-11:
TYPICAL IN-CIRCUIT
SERIAL PROGRAMMING
CONNECTION
To Normal
FIGURE 12-12:
20-Pin PDIP
20-PIN ICD PINOUT
Connections
External
Connector
Signals
In-Circuit Debug Device
*
PIC16F684
NC
1
2
20
19
18
17
16
15
14
13
12
11
ICDCLK
ICDDATA
+5V
0V
VDD
ICDMCLR/VPP
VSS
VDD
RA5
RA4
3
Vss
RA0
RA1
RA2
VPP
MCLR/VPP/RA3
4
5
RA1
RA0
CLK
6
RA3
RC5
Data I/O
7
RC0
RC1
RC2
NC
RC4
8
9
RC3
ICD
10
*
*
*
To Normal
Connections
* Isolation devices (as required)
DS41202F-page 114
© 2007 Microchip Technology Inc.
PIC16F684
TABLE 13-1: OPCODE FIELD
13.0 INSTRUCTION SET SUMMARY
DESCRIPTIONS
The PIC16F684 instruction set is highly orthogonal and
is comprised of three basic categories:
Field
Description
f
W
b
Register file address (0x00 to 0x7F)
Working register (accumulator)
• Byte-oriented operations
• Bit-oriented operations
• Literal and control operations
Bit address within an 8-bit file register
Literal field, constant data or label
k
Each PIC16 instruction is a 14-bit word divided into an
opcode, which specifies the instruction type and one or
more operands, which further specify the operation of
the instruction. The formats for each of the categories
is presented in Figure 13-1, while the various opcode
fields are summarized in Table 13-1.
x
Don’t care location (= 0or 1).
The assembler will generate code with x = 0.
It is the recommended form of use for
compatibility with all Microchip software tools.
d
Destination select; d = 0: store result in W,
d = 1: store result in file register f.
Default is d = 1.
Table 13-2 lists the instructions recognized by the
MPASMTM assembler.
For byte-oriented instructions, ‘f’ represents a file
register designator and ‘d’ represents a destination
designator. The file register designator specifies which
file register is to be used by the instruction.
PC
TO
C
Program Counter
Time-out bit
Carry bit
DC
Z
Digit carry bit
Zero bit
The destination designator specifies where the result of
the operation is to be placed. If ‘d’ is zero, the result is
placed in the W register. If ‘d’ is one, the result is placed
in the file register specified in the instruction.
PD
Power-down bit
FIGURE 13-1:
GENERAL FORMAT FOR
INSTRUCTIONS
For bit-oriented instructions, ‘b’ represents a bit field
designator, which selects the bit affected by the
operation, while ‘f’ represents the address of the file in
which the bit is located.
Byte-oriented file register operations
13
8
7
6
0
For literal and control operations, ‘k’ represents an
8-bit or 11-bit constant, or literal value.
OPCODE
d
f (FILE #)
d = 0for destination W
d = 1for destination f
f = 7-bit file register address
One instruction cycle consists of four oscillator periods;
for an oscillator frequency of 4 MHz, this gives a
nominal instruction execution time of 1 μs. All
instructions are executed within a single instruction
cycle, unless a conditional test is true, or the program
counter is changed as a result of an instruction. When
this occurs, the execution takes two instruction cycles,
with the second cycle executed as a NOP.
Bit-oriented file register operations
13 10 9
b (BIT #)
7
6
0
OPCODE
f (FILE #)
b = 3-bit bit address
f = 7-bit file register address
All instruction examples use the format ‘0xhh’ to
represent a hexadecimal number, where ‘h’ signifies a
hexadecimal digit.
Literal and control operations
General
13
8
7
0
0
13.1 Read-Modify-Write Operations
OPCODE
k (literal)
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.
k = 8-bit immediate value
CALLand GOTOinstructions only
13 11 10
OPCODE
k = 11-bit immediate value
k (literal)
For example, a CLRF PORTA instruction will read
PORTA, clear all the data bits, then write the result back
to PORTA. This example would have the unintended
consequence of clearing the condition that set the RAIF
flag.
© 2007 Microchip Technology Inc.
DS41202F-page 115
PIC16F684
TABLE 13-2: PIC16F684 INSTRUCTION SET
14-Bit Opcode
Mnemonic,
Description
Operands
Status
Affected
Cycles
Notes
MSb
LSb
BYTE-ORIENTED FILE REGISTER OPERATIONS
ADDWF
ANDWF
CLRF
CLRW
COMF
DECF
f, d
f, d
f
Add W and f
AND W with f
Clear f
Clear W
Complement f
Decrement f
Decrement f, Skip if 0
Increment f
Increment f, Skip if 0
Inclusive OR W with f
Move f
1
1
1
1
1
1
1(2)
1
1(2)
1
1
1
1
1
1
1
1
1
00 0111 dfff ffff C, DC, Z
1, 2
1, 2
2
00 0101 dfff ffff
00 0001 lfff ffff
00 0001 0xxx xxxx
00 1001 dfff ffff
00 0011 dfff ffff
00 1011 dfff ffff
00 1010 dfff ffff
00 1111 dfff ffff
00 0100 dfff ffff
00 1000 dfff ffff
00 0000 lfff ffff
00 0000 0xx0 0000
00 1101 dfff ffff
00 1100 dfff ffff
Z
Z
Z
Z
Z
–
f, d
f, d
f, d
f, d
f, d
f, d
f, d
f
1, 2
1, 2
1, 2, 3
1, 2
1, 2, 3
1, 2
1, 2
DECFSZ
INCF
Z
INCFSZ
IORWF
MOVF
MOVWF
NOP
RLF
RRF
SUBWF
SWAPF
XORWF
Z
Z
Move W to f
No Operation
–
f, d
f, d
f, d
f, d
f, d
Rotate Left f through Carry
Rotate Right f through Carry
Subtract W from f
Swap nibbles in f
Exclusive OR W with f
C
C
1, 2
1, 2
1, 2
1, 2
1, 2
00 0010 dfff ffff C, DC, Z
00 1110 dfff ffff
00 0110 dfff ffff
Z
BIT-ORIENTED FILE REGISTER OPERATIONS
BCF
BSF
BTFSC
BTFSS
f, b
f, b
f, b
f, b
Bit Clear f
Bit Set f
Bit Test f, Skip if Clear
Bit Test f, Skip if Set
1
1
1 (2)
1 (2)
01 00bb bfff ffff
1, 2
1, 2
3
01 01bb bfff ffff
01 10bb bfff ffff
01 11bb bfff ffff
3
LITERAL AND CONTROL OPERATIONS
ADDLW
ANDLW
CALL
CLRWDT
GOTO
IORLW
MOVLW
RETFIE
RETLW
RETURN
SLEEP
SUBLW
XORLW
k
k
k
–
k
k
k
–
k
–
–
k
k
Add literal and W
AND literal with W
Call Subroutine
Clear Watchdog Timer
Go to address
1
1
2
1
2
1
1
2
2
2
1
1
1
11 111x kkkk kkkk C, DC, Z
11 1001 kkkk kkkk
10 0kkk kkkk kkkk
Z
00 0000 0110 0100 TO, PD
10 1kkk kkkk kkkk
Inclusive OR literal with W
Move literal to W
11 1000 kkkk kkkk
11 00xx kkkk kkkk
00 0000 0000 1001
11 01xx kkkk kkkk
00 0000 0000 1000
Z
Return from interrupt
Return with literal in W
Return from Subroutine
Go into Standby mode
Subtract W from literal
Exclusive OR literal with W
00 0000 0110 0011 TO, PD
11 110x kkkk kkkk C, DC, Z
11 1010 kkkk kkkk
Z
Note 1: When an I/O register is modified as a function of itself (e.g., MOVF GPIO, 1), 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 to the Timer0 module.
3: If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second
cycle is executed as a NOP.
DS41202F-page 116
© 2007 Microchip Technology Inc.
PIC16F684
13.2 Instruction Descriptions
BCF
Bit Clear f
ADDLW
Add literal and W
Syntax:
[ label ] BCF f,b
Syntax:
[ label ] ADDLW
0 ≤ k ≤ 255
k
Operands:
0 ≤ f ≤ 127
0 ≤ b ≤ 7
Operands:
Operation:
Status Affected:
Description:
(W) + k → (W)
C, DC, Z
Operation:
0→ (f<b>)
Status Affected:
Description:
None
The contents of the W register
are added to the eight-bit literal ‘k’
and the result is placed in the
W register.
Bit ‘b’ in register ‘f’ is cleared.
BSF
Bit Set f
ADDWF
Add W and f
Syntax:
[ label ] BSF f,b
Syntax:
[ label ] ADDWF f,d
Operands:
0 ≤ f ≤ 127
0 ≤ b ≤ 7
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
1→ (f<b>)
Operation:
(W) + (f) → (destination)
Status Affected:
Description:
None
Status Affected: C, DC, Z
Bit ‘b’ in register ‘f’ is set.
Description:
Add the contents of the W register
with register ‘f’. If ‘d’ is ‘0’, the
result is stored in the W register. If
‘d’ is ‘1’, the result is stored back
in register ‘f’.
BTFSC
Bit Test, Skip if Clear
ANDLW
AND literal with W
Syntax:
[ label ] BTFSC f,b
Syntax:
[ label ] ANDLW
0 ≤ k ≤ 255
k
Operands:
0 ≤ f ≤ 127
0 ≤ b ≤ 7
Operands:
Operation:
Status Affected:
Description:
(W) .AND. (k) → (W)
Operation:
skip if (f<b>) = 0
Z
Status Affected: None
The contents of W register are
AND’ed with the eight-bit literal
‘k’. The result is placed in the W
register.
Description: If bit ‘b’ in register ‘f’ is ‘1’, the next
instruction is executed.
If bit ‘b’, in register ‘f’, is ‘0’, the
next instruction is discarded, and
a NOPis executed instead, making
this a 2-cycle instruction.
ANDWF
AND W with f
Syntax:
[ label ] ANDWF f,d
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(W) .AND. (f) → (destination)
Status Affected:
Description:
Z
AND the W register with register
‘f’. If ‘d’ is ‘0’, the result is stored in
the W register. If ‘d’ is ‘1’, the
result is stored back in register ‘f’.
© 2007 Microchip Technology Inc.
DS41202F-page 117
PIC16F684
CLRWDT
Clear Watchdog Timer
BTFSS
Bit Test f, Skip if Set
Syntax:
[ label ] CLRWDT
Syntax:
[ label ] BTFSS f,b
Operands:
Operation:
None
Operands:
0 ≤ f ≤ 127
0 ≤ b < 7
00h → WDT
0→ WDT prescaler,
1→ TO
Operation:
skip if (f<b>) = 1
Status Affected: None
1→ PD
Description:
If bit ‘b’ in register ‘f’ is ‘0’, the next
instruction is executed.
Status Affected: TO, PD
Description:
CLRWDTinstruction resets the
Watchdog Timer. It also resets the
prescaler of the WDT.
If bit ‘b’ is ‘1’, then the next
instruction is discarded and a NOP
is executed instead, making this a
2-cycle instruction.
Status bits TO and PD are set.
CALL
Call Subroutine
COMF
Complement f
Syntax:
[ label ] CALL k
0 ≤ k ≤ 2047
Syntax:
[ label ] COMF f,d
Operands:
Operation:
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
(PC)+ 1→ TOS,
k → PC<10:0>,
(PCLATH<4:3>) → PC<12:11>
Operation:
(f) → (destination)
Status Affected:
Description:
Z
Status Affected: None
The contents of register ‘f’ are
complemented. If ‘d’ is ‘0’, the
result is stored in W. If ‘d’ is ‘1’,
the result is stored back in
register ‘f’.
Description:
Call Subroutine. First, return
address (PC + 1) is pushed onto
the stack. The eleven-bit
immediate address is loaded into
PC bits <10:0>. The upper bits of
the PC are loaded from PCLATH.
CALLis a two-cycle instruction.
CLRF
Clear f
DECF
Decrement f
Syntax:
[ label ] CLRF
0 ≤ f ≤ 127
f
Syntax:
[ label ] DECF f,d
Operands:
Operation:
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
00h → (f)
1→ Z
Operation:
(f) - 1 → (destination)
Status Affected:
Description:
Z
Status Affected:
Description:
Z
The contents of register ‘f’ are
cleared and the Z bit is set.
Decrement register ‘f’. If ‘d’ is ‘0’,
the result is stored in the W
register. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
CLRW
Clear W
Syntax:
[ label ] CLRW
Operands:
Operation:
None
00h → (W)
1→ Z
Status Affected:
Description:
Z
W register is cleared. Zero bit (Z)
is set.
DS41202F-page 118
© 2007 Microchip Technology Inc.
PIC16F684
DECFSZ
Decrement f, Skip if 0
INCFSZ
Increment f, Skip if 0
Syntax:
[ label ] DECFSZ f,d
Syntax:
[ label ] INCFSZ f,d
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) - 1 → (destination);
skip if result = 0
Operation:
(f) + 1 → (destination),
skip if result = 0
Status Affected: None
Status Affected: None
Description:
The contents of register ‘f’ are
Description:
The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result
is placed in the W register. If ‘d’ is
‘1’, the result is placed back in
register ‘f’.
incremented. If ‘d’ is ‘0’, the result
is placed in the W register. If ‘d’ is
‘1’, the result is placed back in
register ‘f’.
If the result is ‘1’, the next
instruction is executed. If the
result is ‘0’, then a NOPis
executed instead, making it a
2-cycle instruction.
If the result is ‘1’, the next
instruction is executed. If the
result is ‘0’, a NOPis executed
instead, making it a 2-cycle
instruction.
GOTO
Unconditional Branch
IORLW
Inclusive OR literal with W
Syntax:
[ label ] GOTO k
0 ≤ k ≤ 2047
Syntax:
[ label ] IORLW k
0 ≤ k ≤ 255
Operands:
Operation:
Operands:
Operation:
Status Affected:
Description:
k → PC<10:0>
PCLATH<4:3> → PC<12:11>
(W) .OR. k → (W)
Z
Status Affected: None
The contents of the W register are
OR’ed with the eight-bit literal ‘k’.
The result is placed in the
W register.
Description:
GOTOis an unconditional branch.
The eleven-bit immediate value is
loaded into PC bits <10:0>. The
upper bits of PC are loaded from
PCLATH<4:3>. GOTOis a
two-cycle instruction.
IORWF
Inclusive OR W with f
INCF
Increment f
Syntax:
[ label ] IORWF f,d
Syntax:
[ label ] INCF f,d
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(W) .OR. (f) → (destination)
Operation:
(f) + 1 → (destination)
Status Affected:
Description:
Z
Status Affected:
Description:
Z
Inclusive OR the W register with
register ‘f’. If ‘d’ is ‘0’, the result is
placed in the W register. If ‘d’ is
‘1’, the result is placed back in
register ‘f’.
The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result
is placed in the W register. If ‘d’ is
‘1’, the result is placed back in
register ‘f’.
© 2007 Microchip Technology Inc.
DS41202F-page 119
PIC16F684
MOVWF
Move W to f
[ label ] MOVWF
0 ≤ f ≤ 127
(W) → (f)
MOVF
Move f
Syntax:
f
Syntax:
Operands:
[ label ] MOVF f,d
Operands:
Operation:
Status Affected:
Description:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) → (dest)
None
Status Affected:
Description:
Z
Move data from W register to
register ‘f’.
The contents of register f is
moved to a destination dependent
upon the status of d. If d = 0,
destination is W register. If d = 1,
the destination is file register f
itself. d = 1is useful to test a file
register since status flag Z is
affected.
Words:
1
1
Cycles:
Example:
MOVW
F
OPTION
Before Instruction
OPTION = 0xFF
Words:
1
1
W
=
0x4F
After Instruction
Cycles:
Example:
OPTION = 0x4F
W
MOVF
FSR, 0
=
0x4F
After Instruction
W
=
value in FSR
register
Z
=
1
MOVLW
Syntax:
Move literal to W
NOP
No Operation
[ label ] MOVLW k
0 ≤ k ≤ 255
Syntax:
[ label ] NOP
Operands:
Operation:
Operands:
Operation:
Status Affected:
Description:
Words:
None
k → (W)
No operation
Status Affected: None
None
Description:
The eight-bit literal ‘k’ is loaded into
W register. The “don’t cares” will
assemble as ‘0’s.
No operation.
1
Cycles:
1
Words:
1
1
NOP
Example:
Cycles:
Example:
MOVLW
0x5A
After Instruction
W
=
0x5A
DS41202F-page 120
© 2007 Microchip Technology Inc.
PIC16F684
RETFIE
Return from Interrupt
[ label ] RETFIE
None
RETLW
Return with literal in W
Syntax:
Syntax:
[ label ] RETLW k
0 ≤ k ≤ 255
Operands:
Operation:
Operands:
Operation:
TOS → PC,
1→ GIE
k → (W);
TOS → PC
Status Affected:
Description:
None
Status Affected:
Description:
None
Return from Interrupt. Stack is
POPed and Top-of-Stack (TOS) is
loaded in the PC. Interrupts are
enabled by setting Global
Interrupt Enable bit, GIE
The W register is loaded with the
eight bit literal ‘k’. The program
counter is loaded from the top of
the stack (the return address).
This is a two-cycle instruction.
(INTCON<7>). This is a two-cycle
instruction.
Words:
1
2
Cycles:
Example:
Words:
1
CALL TABLE;W contains
table
Cycles:
Example:
2
;offset value
RETFIE
•
•
•
;W now has table value
TABLE
After Interrupt
PC = TOS
GIE =
1
ADDWF PC ;W = offset
RETLW k1 ;Begin table
RETLW k2
;
•
•
•
RETLW kn ; End of table
Before Instruction
W
=
0x07
After Instruction
W
=
value of k8
RETURN
Return from Subroutine
Syntax:
[ label ] RETURN
None
Operands:
Operation:
TOS → PC
Status Affected: None
Description: Return from subroutine. The stack
is POPed and the top of the stack
(TOS) is loaded into the program
counter. This is a two-cycle
instruction.
© 2007 Microchip Technology Inc.
DS41202F-page 121
PIC16F684
RLF
Rotate Left f through Carry
SLEEP
Enter Sleep mode
[ label ] SLEEP
None
Syntax:
Operands:
[ label ]
RLF f,d
Syntax:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
Operation:
00h → WDT,
0→ WDT prescaler,
1→ TO,
Operation:
See description below
C
Status Affected:
Description:
0→ PD
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 the W register.
If ‘d’ is ‘1’, the result is stored
back in register ‘f’.
Status Affected:
Description:
TO, PD
The power-down Status bit, PD is
cleared. Time-out Status bit, TO
is set. Watchdog Timer and its
prescaler are cleared.
The processor is put into Sleep
mode with the oscillator stopped.
C
Register f
Words:
1
1
Cycles:
Example:
RLF
REG1,0
Before Instruction
REG1
C
=
=
1110 0110
0
After Instruction
REG1
W
C
=
=
=
1110 0110
1100 1100
1
SUBLW
Subtract W from literal
RRF
Rotate Right f through Carry
Syntax:
[ label ] SUBLW k
0 ≤ k ≤ 255
Syntax:
[ label ] RRF f,d
Operands:
Operation:
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
k - (W) → (W)
Operation:
See description below
C
Status Affected: C, DC, Z
Status Affected:
Description:
Description: The W register is subtracted (2’s
complement method) from the
eight-bit literal ‘k’. The result is
placed in the W register.
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 the W register.
If ‘d’ is ‘1’, the result is placed
back in register ‘f’.
C = 0
W > k
C = 1
W ≤ k
DC = 0
DC = 1
W<3:0> > k<3:0>
W<3:0> ≤ k<3:0>
C
Register f
DS41202F-page 122
© 2007 Microchip Technology Inc.
PIC16F684
SUBWF
Subtract W from f
XORLW
Exclusive OR literal with W
Syntax:
[ label ] SUBWF f,d
Syntax:
[ label ] XORLW k
0 ≤ k ≤ 255
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
Operation:
Status Affected:
Description:
(W) .XOR. k → (W)
Z
Operation:
(f) - (W) → (destination)
Status Affected: C, DC, Z
The contents of the W register
are XOR’ed with the eight-bit
literal ‘k’. The result is placed in
the W register.
Description:
Subtract (2’s complement method)
W register from register ‘f’. If ‘d’ is
‘0’, the result is stored in the W
register. If ‘d’ is ‘1’, the result is
stored back in register ‘f.
C = 0
W > f
C = 1
W ≤ f
DC = 0
DC = 1
W<3:0> > f<3:0>
W<3:0> ≤ f<3:0>
SWAPF
Swap Nibbles in f
XORWF
Exclusive OR W with f
Syntax:
[ label ] SWAPF f,d
Syntax:
[ label ] XORWF f,d
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f<3:0>) → (destination<7:4>),
(f<7:4>) → (destination<3:0>)
Operation:
(W) .XOR. (f) → (destination)
Status Affected:
Description:
Z
Status Affected: None
Exclusive OR the contents of the
W register with register ‘f’. If ‘d’ is
‘0’, the result is stored in the W
register. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
Description: The upper and lower nibbles of
register ‘f’ are exchanged. If ‘d’ is
‘0’, the result is placed in the W
register. If ‘d’ is ‘1’, the result is
placed in register ‘f’.
© 2007 Microchip Technology Inc.
DS41202F-page 123
PIC16F684
NOTES:
DS41202F-page 124
© 2007 Microchip Technology Inc.
PIC16F684
14.1 MPLAB Integrated Development
Environment Software
14.0 DEVELOPMENT SUPPORT
The PIC® 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®
operating system-based application that contains:
• Integrated Development Environment
- MPLAB® IDE Software
• Assemblers/Compilers/Linkers
- MPASMTM Assembler
• A single graphical interface to all debugging tools
- Simulator
- MPLAB C18 and MPLAB C30 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 ASM30 Assembler/Linker/Library
• Simulators
- MPLAB SIM Software Simulator
• Emulators
• Customizable data windows with direct edit of
contents
- MPLAB ICE 2000 In-Circuit Emulator
- MPLAB REAL ICE™ In-Circuit Emulator
• In-Circuit Debugger
• High-level source code debugging
• Visual device initializer for easy register
initialization
- MPLAB ICD 2
• Mouse over variable inspection
• Device Programmers
• Drag and drop variables from source to watch
windows
- PICSTART® Plus Development Programmer
- MPLAB PM3 Device Programmer
- PICkit™ 2 Development Programmer
• Extensive on-line help
• Integration of select third party tools, such as
HI-TECH Software C Compilers and IAR
C Compilers
• Low-Cost Demonstration and Development
Boards and Evaluation Kits
The MPLAB IDE allows you to:
• Edit your source files (either assembly or C)
• One touch assemble (or compile) and download
to PIC MCU emulator and simulator tools
(automatically updates all project information)
• Debug using:
- Source files (assembly or C)
- 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 increased flexibility
and power.
© 2007 Microchip Technology Inc.
DS41202F-page 125
PIC16F684
14.2 MPASM Assembler
14.5 MPLAB ASM30 Assembler, Linker
and Librarian
The MPASM Assembler is a full-featured, universal
macro assembler for all PIC MCUs.
MPLAB ASM30 Assembler produces relocatable
machine code from symbolic assembly language for
dsPIC30F devices. MPLAB C30 C Compiler uses the
assembler to produce its 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:
The MPASM Assembler generates relocatable object
files for the MPLINK Object Linker, Intel® standard HEX
files, MAP files to detail memory usage and symbol
reference, absolute LST files that contain source lines
and generated machine code and COFF files for
debugging.
The MPASM Assembler features include:
• Integration into MPLAB IDE projects
• Support for the entire dsPIC30F instruction set
• Support for fixed-point and floating-point data
• Command line interface
• User-defined macros to streamline
assembly code
• Rich directive set
• Conditional assembly for multi-purpose
source files
• Flexible macro language
• MPLAB IDE compatibility
• Directives that allow complete control over the
assembly process
14.6 MPLAB SIM Software Simulator
14.3 MPLAB C18 and MPLAB C30
C Compilers
The MPLAB SIM Software Simulator allows code
development in a PC-hosted environment by simulat-
ing the PIC MCUs and dsPIC® DSCs on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a comprehensive stimulus controller. Registers can be
logged to files for further run-time analysis. The trace
buffer and logic analyzer display extend the power of
the simulator to record and track program execution,
actions on I/O, most peripherals and internal registers.
The MPLAB C18 and MPLAB C30 Code Development
Systems are complete ANSI
C
compilers for
Microchip’s PIC18 and PIC24 families of microcontrol-
lers and the dsPIC30 and dsPIC33 family of digital sig-
nal controllers. 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.
The MPLAB SIM Software Simulator fully supports
symbolic debugging using the MPLAB C18 and
MPLAB C30 C Compilers, and the MPASM and
MPLAB ASM30 Assemblers. The software simulator
offers the flexibility to develop and debug code outside
of the hardware laboratory environment, making it an
excellent, economical software development tool.
14.4 MPLINK Object Linker/
MPLIB Object Librarian
The MPLINK Object Linker combines relocatable
objects created by the MPASM Assembler and the
MPLAB C18 C Compiler. It can link relocatable objects
from precompiled libraries, using directives from a
linker script.
The MPLIB Object Librarian manages the creation and
modification of library files of precompiled 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
• Enhanced code maintainability by grouping
related modules together
• Flexible creation of libraries with easy module
listing, replacement, deletion and extraction
DS41202F-page 126
© 2007 Microchip Technology Inc.
PIC16F684
14.7 MPLAB ICE 2000
High-Performance
14.9 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
USB interface. This tool is based on the Flash PIC
MCUs and can be used to develop for these and other
PIC MCUs and dsPIC DSCs. 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 Integrated Development
Environment. This enables a designer to develop and
debug source code by setting breakpoints, single step-
ping and watching variables, and 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 PIC devices.
In-Circuit Emulator
The MPLAB ICE 2000 In-Circuit Emulator is intended
to provide the product development engineer with a
complete microcontroller design tool set for PIC
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.
The MPLAB ICE 2000 is a full-featured emulator
system with enhanced trace, trigger and data monitor-
ing features. Interchangeable processor modules allow
the system to be easily reconfigured for emulation of
different processors. The architecture of the MPLAB
ICE 2000 In-Circuit Emulator allows expansion to
support new PIC 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.
14.10 MPLAB PM3 Device Programmer
The MPLAB PM3 Device Programmer is a universal,
CE compliant device programmer with programmable
voltage verification at VDDMIN and VDDMAX for
maximum reliability. It features a large LCD display
(128 x 64) for menus and error messages and a modu-
lar, detachable socket assembly to support various
package types. The ICSP™ cable assembly is included
as a standard item. In Stand-Alone mode, the MPLAB
PM3 Device Programmer can read, verify and program
PIC devices without a PC connection. It can also set
code protection in this mode. The MPLAB PM3
connects to the host PC via an RS-232 or USB cable.
The MPLAB PM3 has high-speed communications and
optimized algorithms for quick programming of large
memory devices and incorporates an SD/MMC card for
file storage and secure data applications.
14.8 MPLAB REAL ICE In-Circuit
Emulator System
MPLAB REAL ICE In-Circuit Emulator System is
Microchip’s next generation high-speed emulator for
Microchip Flash DSC® and MCU devices. It debugs and
programs PIC® and dsPIC® Flash microcontrollers with
the easy-to-use, powerful graphical user interface of the
MPLAB Integrated Development Environment (IDE),
included with each kit.
The MPLAB REAL ICE probe is connected to the design
engineer’s PC using a high-speed USB 2.0 interface and
is connected to the target with either a connector
compatible with the popular MPLAB ICD 2 system
(RJ11) or with the new high speed, noise tolerant, low-
voltage differential signal (LVDS) interconnection
(CAT5).
MPLAB REAL ICE is field upgradeable through future
firmware downloads in MPLAB IDE. In upcoming
releases of MPLAB IDE, new devices will be supported,
and new features will be added, such as software break-
points and assembly code trace. MPLAB REAL ICE
offers significant advantages over competitive emulators
including low-cost, full-speed emulation, real-time
variable watches, trace analysis, complex breakpoints, a
ruggedized probe interface and long (up to three meters)
interconnection cables.
© 2007 Microchip Technology Inc.
DS41202F-page 127
PIC16F684
14.11 PICSTART Plus Development
Programmer
14.13 Demonstration, Development and
Evaluation Boards
The PICSTART Plus Development Programmer is an
easy-to-use, low-cost, prototype programmer. It
connects 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 PIC devices in DIP packages 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.
A wide variety of demonstration, development and
evaluation boards for various PIC MCUs and dsPIC
DSCs allows quick application development on fully func-
tional systems. Most boards include prototyping areas for
adding custom circuitry and provide application firmware
and source code for examination and modification.
The boards support a variety of features, including LEDs,
temperature sensors, switches, speakers, RS-232
interfaces, LCD displays, potentiometers and additional
EEPROM memory.
The demonstration and development boards can be
used in teaching environments, for prototyping custom
circuits and for learning about various microcontroller
applications.
14.12 PICkit 2 Development Programmer
The PICkit™ 2 Development Programmer is a low-cost
programmer and selected Flash device debugger with
an easy-to-use interface for programming many of
Microchip’s baseline, mid-range and PIC18F families of
Flash memory microcontrollers. The PICkit 2 Starter Kit
includes a prototyping development board, twelve
sequential lessons, software and HI-TECH’s PICC™
Lite C compiler, and is designed to help get up to speed
quickly using PIC® microcontrollers. The kit provides
everything needed to program, evaluate and develop
applications using Microchip’s powerful, mid-range
Flash memory family of microcontrollers.
In addition to the PICDEM™ and dsPICDEM™ demon-
stration/development board series of circuits, Microchip
has a line of evaluation kits and demonstration software
®
for analog filter design, KEELOQ security ICs, CAN,
IrDA®, PowerSmart® battery management, SEEVAL®
evaluation system, Sigma-Delta ADC, flow rate
sensing, plus many more.
Check the Microchip web page (www.microchip.com)
and the latest “Product Selector Guide” (DS00148) for
the complete list of demonstration, development and
evaluation kits.
DS41202F-page 128
© 2007 Microchip Technology Inc.
PIC16F684
15.0 ELECTRICAL SPECIFICATIONS
(†)
Absolute Maximum Ratings
Ambient temperature under bias..........................................................................................................-40° to +125°C
Storage temperature ........................................................................................................................ -65°C to +150°C
Voltage on VDD with respect to VSS ................................................................................................... -0.3V to +6.5V
Voltage on MCLR with respect to Vss ............................................................................................... -0.3V to +13.5V
Voltage on all other pins with respect to VSS ........................................................................... -0.3V to (VDD + 0.3V)
Total power dissipation(1) ............................................................................................................................... 800 mW
Maximum current out of VSS pin ...................................................................................................................... 95 mA
Maximum current into VDD pin ......................................................................................................................... 95 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 PORTA and PORTC (combined) ........................................................................... 90 mA
Maximum current sourced PORTA and PORTC (combined)........................................................................... 90 mA
Note 1: Power dissipation is calculated as follows: PDIS = VDD x {IDD – ∑ IOH} + ∑ {(VDD – VOH) x IOH} + ∑(VOl x IOL).
† 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 above maximum rating conditions for
extended periods may affect device reliability.
© 2007 Microchip Technology Inc.
DS41202F-page 129
PIC16F684
FIGURE 15-1:
PIC16F684 VOLTAGE-FREQUENCY GRAPH,
-40°C ≤ TA ≤ +125°C
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
0
8
10
20
Frequency (MHz)
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.
FIGURE 15-2:
HFINTOSC FREQUENCY ACCURACY OVER DEVICE VDD AND TEMPERATURE
125
85
60
25
0
± 5%
± 2%
± 1%
2.0
2.5
3.0
3.5
4.0
VDD (V)
4.5
5.0
5.5
DS41202F-page 130
© 2007 Microchip Technology Inc.
PIC16F684
15.1 DC Characteristics: PIC16F684-I (Industrial)
PIC16F684-E (Extended)
Standard Operating Conditions (unless otherwise stated)
DC CHARACTERISTICS
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No.
Unit
s
Sym
Characteristic
Min Typ† Max
Conditions
VDD
Supply Voltage
2.0
2.0
3.0
4.5
—
—
—
—
5.5
5.5
5.5
5.5
V
V
V
V
FOSC < = 8 MHz: HFINTOSC, EC
FOSC < = 4 MHz
FOSC < = 10 MHz
D001
D001C
D001D
FOSC < = 20 MHz
D002* VDR
RAM Data Retention
Voltage(1)
1.5
—
—
V
Device in Sleep mode
D003 VPOR
VDD Start Voltage to
ensure internal Power-on
Reset signal
—
VSS
—
V
See Section 12.3.1 “Power-On Reset
(POR)” for details.
D004* SVDD
VDD Rise Rate to ensure
internal Power-on Reset
signal
0.05
—
—
V/ms See Section 12.3.1 “Power-On Reset
(POR)” for details.
*
These parameters are characterized but not tested.
†
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: This is the limit to which VDD can be lowered in Sleep mode without losing RAM data.
© 2007 Microchip Technology Inc.
DS41202F-page 131
PIC16F684
15.2 DC Characteristics: PIC16F684-I (Industrial)
PIC16F684-E (Extended)
Standard Operating Conditions (unless otherwise stated)
DC CHARACTERISTICS
Param
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Conditions
Units
Device Characteristics
Min
Typ†
Max
No.
VDD
Note
D010
Supply Current (IDD)(1, 2)
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
11
18
16
28
μA
μA
μA
μA
μA
μA
μA
μA
mA
μA
μA
μA
μA
μA
mA
μA
μA
μA
μA
μA
mA
μA
μA
mA
μA
μA
mA
mA
mA
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
4.5
5.0
FOSC = 32 kHz
LP Oscillator mode
35
54
D011*
D012
D013*
D014
D015
D016*
D017
D018
D019
140
220
380
260
420
0.8
240
380
550
360
650
1.1
FOSC = 1 MHz
XT Oscillator mode
FOSC = 4 MHz
XT Oscillator mode
130
215
360
220
375
0.65
8
220
360
520
340
550
1.0
FOSC = 1 MHz
EC Oscillator mode
FOSC = 4 MHz
EC Oscillator mode
20
FOSC = 31 kHz
LFINTOSC mode
16
40
31
65
340
500
0.8
450
700
1.2
FOSC = 4 MHz
HFINTOSC mode
410
700
1.30
230
400
0.63
2.6
650
950
1.65
400
680
1.1
FOSC = 8 MHz
HFINTOSC mode
FOSC = 4 MHz
EXTRC mode(3)
3.25
3.35
FOSC = 20 MHz
HS Oscillator mode
2.8
*
These parameters are characterized but not tested.
†
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: 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 disabled.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O
pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have
an impact on the current consumption.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can
be extended by the formula IR = VDD/2REXT (mA) with REXT in kΩ.
DS41202F-page 132
© 2007 Microchip Technology Inc.
PIC16F684
15.3 DC Characteristics: PIC16F684-I (Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
DC CHARACTERISTICS
Conditions
Note
Param
No.
Device Characteristics
Min
Typ†
Max
Units
VDD
D020
Power-down Base
Current(IPD)(2)
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
0.05
0.15
0.35
150
1.0
2.0
3.0
42
1.2
1.5
1.8
500
2.2
4.0
7.0
60
μA
μA
μA
nA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
2.0
3.0
5.0
3.0
2.0
3.0
5.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
3.0
5.0
WDT, BOR, Comparators, VREF and
T1OSC disabled
-40°C ≤ TA ≤ +25°C
WDT Current(1)
D021
D022
D023
BOR Current(1)
85
122
45
32
Comparator Current(1), both
comparators enabled
60
78
120
30
160
36
D024
D025*
D026
D027
CVREF Current(1) (high range)
CVREF Current(1) (low range)
T1OSC Current(1), 32.768 kHz
45
55
75
95
39
47
59
72
98
124
7.0
8.0
12
4.5
5.0
6.0
0.30
0.36
1.6
1.9
A/D Current(1), no conversion in
progress
*
These parameters are characterized but not tested.
†
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: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this
peripheral is enabled. The peripheral Δ current can be determined by subtracting the base IDD or IPD
current from this limit. Max values should be used when calculating total current consumption.
2: 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.
© 2007 Microchip Technology Inc.
DS41202F-page 133
PIC16F684
15.4 DC Characteristics: PIC16F684-E (Extended)
Standard Operating Conditions (unless otherwise stated)
DC CHARACTERISTICS
Operating temperature
-40°C ≤ TA ≤ +125°C for extended
Conditions
Units
Param
No.
Device Characteristics Min
Typ†
Max
VDD
Note
D020E Power-down Base
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
0.05
0.15
0.35
1
9
11
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
2.0
3.0
5.0
2.0
3.0
5.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
2.0
3.0
5.0
3.0
5.0
WDT, BOR, Comparators, VREF and
T1OSC disabled
Current (IPD)(2)
15
D021E
17.5
19
WDT Current(1)
BOR Current(1)
2
3
22
D022E
D023E
42
85
32
60
120
30
45
75
39
59
98
4.5
5
65
127
45
Comparator Current(1), both
comparators enabled
78
160
70
D024E
D025E*
D026E
D027E
CVREF Current(1) (high range)
CVREF Current(1) (low range)
T1OSC Current(1), 32.768 kHz
90
120
91
117
156
25
30
6
40
0.30
0.36
12
A/D Current(1), no conversion in
progress
16
*
These parameters are characterized but not tested.
†
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: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this
peripheral is enabled. The peripheral Δ current can be determined by subtracting the base IDD or IPD
current from this limit. Max values should be used when calculating total current consumption.
2: 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.
DS41202F-page 134
© 2007 Microchip Technology Inc.
PIC16F684
15.5 DC Characteristics: PIC16F684-I (Industrial)
PIC16F684-E (Extended)
Standard Operating Conditions (unless otherwise stated)
DC CHARACTERISTICS
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No.
Sym
Characteristic
Min
Typ†
Max
Units
Conditions
VIL
Input Low Voltage
I/O Port:
D030
D030A
D031
D032
D033
D033A
with TTL buffer
Vss
Vss
Vss
VSS
VSS
VSS
—
—
—
—
—
—
0.8
V
V
V
V
V
V
4.5V ≤ VDD ≤ 5.5V
0.15 VDD
0.2 VDD
0.2 VDD
0.3
2.0V ≤ VDD ≤ 4.5V
2.0V ≤ VDD ≤ 5.5V
with Schmitt Trigger buffer
(1)
MCLR, OSC1 (RC mode)
OSC1 (XT and LP modes)
OSC1 (HS mode)
Input High Voltage
I/O ports:
0.3 VDD
VIH
—
—
—
—
—
—
—
—
D040
with TTL buffer
2.0
0.25 VDD + 0.8
0.8 VDD
0.8 VDD
1.6
VDD
VDD
VDD
VDD
VDD
VDD
VDD
V
V
V
V
V
V
V
4.5V ≤ VDD ≤ 5.5V
2.0V ≤ VDD ≤ 4.5V
2.0V ≤ VDD ≤ 5.5V
D040A
D041
with Schmitt Trigger buffer
MCLR
D042
D043
OSC1 (XT and LP modes)
OSC1 (HS mode)
D043A
D043B
0.7 VDD
0.9 VDD
OSC1 (RC mode)
(Note 1)
(2)
IIL
Input Leakage Current
D060
I/O ports
—
0.1
1
μA VSS ≤ VPIN ≤ VDD,
Pin at high-impedance
(3)
D061
D063
MCLR
—
—
0.1
0.1
5
5
μA VSS ≤ VPIN ≤ VDD
OSC1
μA VSS ≤ VPIN ≤ VDD, XT, HS and
LP oscillator configuration
D070* IPUR
VOL
PORTA Weak Pull-up Current
50
—
250
—
400
0.6
—
μA VDD = 5.0V, VPIN = VSS
(5)
Output Low Voltage
D080
I/O ports
V
V
IOL = 8.5 mA, VDD = 4.5V (Ind.)
IOH = -3.0 mA, VDD = 4.5V (Ind.)
(5)
VOH
Output High Voltage
D090
I/O ports
VDD – 0.7
—
*
These parameters are characterized but not tested.
†
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: In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external
clock in RC mode.
2: Negative current is defined as current sourced by the pin.
3: 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.
4: See Section 10.4.1 “Using the Data EEPROM” for additional information.
5: Including OSC2 in CLKOUT mode.
© 2007 Microchip Technology Inc.
DS41202F-page 135
PIC16F684
15.5 DC Characteristics: PIC16F684-I (Industrial)
PIC16F684-E (Extended) (Continued)
Standard Operating Conditions (unless otherwise stated)
DC CHARACTERISTICS
Param
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Sym
Characteristic
Min
Typ†
Max
Units
Conditions
No.
D100
IULP
Ultra Low-Power Wake-Up
Current
—
200
—
nA See Application Note AN879,
“Using the Microchip Ultra
Low-Power Wake-up Module”
(DS00879)
Capacitive Loading Specs on
Output Pins
D101* COSC2 OSC2 pin
—
—
—
—
15
50
pF In XT, HS and LP modes when
external clock is used to drive
OSC1
D101A* CIO
All I/O pins
pF
Data EEPROM Memory
Byte Endurance
Byte Endurance
VDD for Read/Write
D120
ED
100K
10K
1M
100K
—
—
—
E/W -40°C ≤ TA ≤ +85°C
E/W +85°C ≤ TA ≤ +125°C
D120A ED
D121
VDRW
VMIN
5.5
V
Using EECON1 to read/write
VMIN = Minimum operating
voltage
D122
D123
TDEW
Erase/Write Cycle Time
Characteristic Retention
—
5
6
ms
TRETD
40
—
—
Year Provided no other specifications
are violated
D124
TREF
Number of Total Erase/Write
Cycles before Refresh
1M
10M
—
E/W -40°C ≤ TA ≤ +85°C
(4)
Program Flash Memory
Cell Endurance
D130
EP
10K
1K
100K
10K
—
—
—
E/W -40°C ≤ TA ≤ +85°C
E/W +85°C ≤ TA ≤ +125°C
D130A ED
Cell Endurance
D131
VPR
VDD for Read
VMIN
5.5
V
VMIN = Minimum operating
voltage
D132
D133
D134
VPEW
TPEW
TRETD
VDD for Erase/Write
4.5
—
—
2
5.5
2.5
—
V
Erase/Write cycle time
Characteristic Retention
ms
40
—
Year Provided no other specifications
are violated
*
These parameters are characterized but not tested.
†
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: In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external
clock in RC mode.
2: Negative current is defined as current sourced by the pin.
3: 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.
4: See Section 10.4.1 “Using the Data EEPROM” for additional information.
5: Including OSC2 in CLKOUT mode.
DS41202F-page 136
© 2007 Microchip Technology Inc.
PIC16F684
15.6 Thermal Considerations
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C
Param
Sym
No.
Characteristic
Typ
Units
Conditions
TH01
θJA
Thermal Resistance
Junction to Ambient
69.8
85.0
100.4
46.3
32.5
31.0
31.7
2.6
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C
14-pin PDIP package
14-pin SOIC package
14-pin TSSOP package
16-pin QFN 4x0.9mm package
14-pin PDIP package
TH02
θJC
Thermal Resistance
Junction to Case
14-pin SOIC package
14-pin TSSOP package
16-pin QFN 4x0.9mm package
For derated power calculations
PD = PINTERNAL + PI/O
TH03
TH04
TH05
TJ
Junction Temperature
Power Dissipation
150
—
PD
W
PINTERNAL Internal Power Dissipation
—
W
PINTERNAL = IDD x VDD
(NOTE 1)
TH06
TH07
PI/O
I/O Power Dissipation
Derated Power
—
—
W
W
PI/O = Σ (IOL * VOL) + Σ (IOH * (VDD - VOH))
PDER = (TJ - TA)/θJA
(NOTE 2, 3)
PDER
Note 1: IDD is current to run the chip alone without driving any load on the output pins.
2: TA = Ambient Temperature.
3: Maximum allowable power dissipation is the lower value of either the absolute maximum total power
dissipation or derated power (PDER).
© 2007 Microchip Technology Inc.
DS41202F-page 137
PIC16F684
15.7
Timing Parameter Symbology
The timing parameter symbols have been created with
one of the following formats:
1. TppS2ppS
2. TppS
T
F
Frequency
Lowercase letters (pp) and their meanings:
pp
cc
T
Time
CCP1
CLKOUT
CS
osc
rd
OSC1
RD
ck
cs
di
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
H
I
Fall
P
R
V
Z
Period
High
Rise
Invalid (High-impedance)
Low
Valid
L
High-impedance
FIGURE 15-3:
LOAD CONDITIONS
Load Condition
Pin
CL
VSS
Legend: CL
=
50 pF for all pins
15 pF for OSC2 output
DS41202F-page 138
© 2007 Microchip Technology Inc.
PIC16F684
15.8 AC Characteristics: PIC16F684 (Industrial, Extended)
FIGURE 15-4:
CLOCK TIMING
Q4
Q1
Q2
Q3
Q4
Q1
OSC1/CLKIN
OS02
OS04
OS04
OS03
OSC2/CLKOUT
(LP,XT,HS Modes)
OSC2/CLKOUT
(CLKOUT Mode)
TABLE 15-1: CLOCK OSCILLATOR TIMING REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C
Param
Sym
No.
Characteristic
Min
Typ†
Max
Units
Conditions
(1)
OS01
OS02
OS03
FOSC
TOSC
TCY
External CLKIN Frequency
DC
DC
DC
DC
—
—
—
37
kHz LP Oscillator mode
MHz XT Oscillator mode
MHz HS Oscillator mode
MHz EC Oscillator mode
kHz LP Oscillator mode
MHz XT Oscillator mode
MHz HS Oscillator mode
MHz RC Oscillator mode
4
—
20
—
20
(1)
Oscillator Frequency
32.768
—
—
0.1
1
4
—
20
DC
27
250
50
50
—
—
4
(1)
External CLKIN Period
—
•
μs
ns
ns
ns
μs
ns
ns
ns
ns
μs
ns
ns
ns
ns
ns
LP Oscillator mode
XT Oscillator mode
HS Oscillator mode
EC Oscillator mode
LP Oscillator mode
XT Oscillator mode
HS Oscillator mode
RC Oscillator mode
TCY = 4/FOSC
—
•
—
•
—
•
(1)
Oscillator Period
30.5
—
—
250
50
250
200
2
10,000
—
1,000
—
DC
—
—
—
•
—
(1)
Instruction Cycle Time
TCY
—
OS04* TosH, External CLKIN High,
TosL External CLKIN Low
LP oscillator
100
20
0
—
XT oscillator
—
HS oscillator
OS05* TosR, External CLKIN Rise,
TosF External CLKIN Fall
—
LP oscillator
0
—
•
XT oscillator
0
—
•
HS oscillator
*
These parameters are characterized but not tested.
†
Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and
are not tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. 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 OSC1 pin. When an external clock input is used, the ‘max’ cycle time limit is ‘DC’ (no clock) for all
devices.
© 2007 Microchip Technology Inc.
DS41202F-page 139
PIC16F684
TABLE 15-2: OSCILLATOR PARAMETERS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature
-40°C ≤ TA ≤ +125°C
Param
Sym
No.
Freq
Tolerance
Characteristic
Min
Typ†
Max
Units
TOSC Slowest clock
ms LFINTOSC/64
Conditions
OS06
OS07
OS08
TWARM
Internal Oscillator Switch
—
—
—
2
(3)
when running
TSC
Fail-Safe Sample Clock
—
21
—
—
(1)
Period
HFOSC
Internal Calibrated
HFINTOSC Frequency
1%
2%
7.92
7.84
8.0
8.0
8.08
8.16
MHz VDD = 3.5V, 25°C
(2)
MHz 2.5V ≤ VDD ≤ 5.5V,
0°C ≤ TA ≤ +85°C
5%
—
7.60
15
8.0
31
8.40
45
MHz 2.0V ≤ VDD ≤ 5.5V,
-40°C ≤ TA ≤ +85°C (Ind.),
-40°C ≤ TA ≤ +125°C (Ext.)
OS09*
OS10*
LFOSC
Internal Uncalibrated
LFINTOSC Frequency
kHz
TIOSC
ST
HFINTOSC Oscillator
Wake-up from Sleep
Start-up Time
—
—
—
5.5
3.5
3
12
7
24
14
11
μs
μs
μs
VDD = 2.0V, -40°C to +85°C
VDD = 3.0V, -40°C to +85°C
VDD = 5.0V, -40°C to +85°C
6
*
These parameters are characterized but not tested.
†
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: Instruction cycle period (TCY) equals four times the input oscillator time base period. 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 pin. When an external clock input is used, the ‘max’ cycle time limit is ‘DC’ (no clock)
for all devices.
2: To ensure these oscillator frequency tolerances, VDD and VSS must be capacitively decoupled as close to the
device as possible. 0.1 μF and 0.01 μF values in parallel are recommended.
3: By design.
DS41202F-page 140
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 15-5:
CLKOUT AND I/O TIMING
Cycle
Write
Q4
Fetch
Q1
Read
Q2
Execute
Q3
Fosc
OS12
OS18
OS11
OS20
OS21
CLKOUT
OS19
OS13
OS16
OS17
I/O pin
(Input)
OS14
OS15
I/O pin
(Output)
New Value
Old Value
OS18, OS19
TABLE 15-3: CLKOUT AND I/O TIMING PARAMETERS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C ≤ TA ≤ +125°C
Param
No.
Sym
Characteristic
Min
Typ† Max Units
Conditions
OS11
OS12
OS13
OS14
OS15
OS16
TOSH2CKL FOSC↑ to CLKOUT↓ (1)
TOSH2CKH FOSC↑ to CLKOUT↑ (1)
—
—
—
—
70
72
20
—
ns VDD = 5.0V
—
—
—
50
—
ns VDD = 5.0V
ns
TCKL2IOV
CLKOUT↓ to Port out valid(1)
TIOV2CKH Port input valid before CLKOUT↑(1)
TOSC + 200 ns
ns
TOSH2IOV FOSC↑ (Q1 cycle) to Port out valid
—
70*
—
ns VDD = 5.0V
ns VDD = 5.0V
TOSH2IOI
FOSC↑ (Q2 cycle) to Port input invalid
(I/O in hold time)
50
OS17
OS18
OS19
TIOV2OSH Port input valid to FOSC↑ (Q2 cycle)
20
—
—
ns
(I/O in setup time)
TIOR
TIOF
Port output rise time(2)
—
—
15
40
72
32
ns VDD = 2.0V
VDD = 5.0V
Port output fall time(2)
—
—
28
15
55
30
ns VDD = 2.0V
VDD = 5.0V
OS20* TINP
OS21* TRAP
INT pin input high or low time
25
—
—
—
—
ns
ns
PORTA interrupt-on-change new input
level time
TCY
*
These parameters are characterized but not tested.
Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated.
†
Note 1: Measurements are taken in RC mode where CLKOUT output is 4 x TOSC.
2: Includes OSC2 in CLKOUT mode.
© 2007 Microchip Technology Inc.
DS41202F-page 141
PIC16F684
FIGURE 15-6:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND
POWER-UP TIMER TIMING
VDD
MCLR
30
Internal
POR
33
PWRT
Time-out
32
OSC
Start-Up Time
(1)
Internal Reset
Watchdog Timer
(1)
Reset
31
34
34
I/O pins
Note 1: Asserted low.
FIGURE 15-7:
BROWN-OUT RESET TIMING AND CHARACTERISTICS
VDD
VBOR + VHYST
VBOR
(Device in Brown-out Reset)
(Device not in Brown-out Reset)
37
Reset
(due to BOR)
33*
*
64 ms delay only if PWRTE bit in the Configuration Word register is programmed to ‘0’.
DS41202F-page 142
© 2007 Microchip Technology Inc.
PIC16F684
TABLE 15-4: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET PARAMETERS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C ≤ TA ≤ +125°C
Param
No.
Sym
TMCL
Characteristic
Min
Typ†
Max Units
Conditions
30
MCLR Pulse Width (low)
2
5
—
—
—
—
μs VDD = 5V, -40°C to +85°C
μs VDD = 5V
31
32
TWDT
TOST
Watchdog Timer Time-out
Period (No Prescaler)
10
10
16
16
29
31
ms VDD = 5V, -40°C to +85°C
ms VDD = 5V
Oscillation Start-up Timer
Period(1, 2)
—
1024
—
TOSC (NOTE 3)
33*
34*
TPWRT Power-up Timer Period
40
—
65
—
140
2.0
ms
TIOZ
I/O High-impedance from
MCLR Low or Watchdog Timer
Reset
μs
35
VBOR
VHYST
TBOR
Brown-out Reset Voltage
2.0
—
—
50
—
2.2
—
V
(NOTE 4)
36*
37*
Brown-out Reset Hysteresis
mV
Brown-out Reset Minimum
Detection Period
100
—
μs VDD ≤ VBOR
*
These parameters are characterized but not tested.
†
Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. 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 oper-
ation and/or higher than expected current consumption. All devices are tested to operate at ‘min’ values
with an external clock applied to the OSC1 pin. When an external clock input is used, the ‘max’ cycle time
limit is ‘DC’ (no clock) for all devices.
2: By design.
3: Period of the slower clock.
4: To ensure these voltage tolerances, VDD and VSS must be capacitively decoupled as close to the device as
possible. 0.1 μF and 0.01 μF values in parallel are recommended.
© 2007 Microchip Technology Inc.
DS41202F-page 143
PIC16F684
FIGURE 15-8:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI
40
41
42
T1CKI
45
46
49
47
TMR0 or
TMR1
TABLE 15-5: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature
-40°C ≤ TA ≤ +125°C
Param
Sym
No.
Characteristic
Min
Typ†
Max
Units
Conditions
40*
41*
42*
TT0H
TT0L
TT0P
T0CKI High Pulse Width
No Prescaler
With Prescaler
No Prescaler
With Prescaler
0.5 TCY + 20
—
—
—
—
—
—
—
—
—
—
ns
ns
ns
ns
10
0.5 TCY + 20
10
T0CKI Low Pulse Width
T0CKI Period
Greater of:
20 or TCY + 40
N
ns N = prescale value
(2, 4, ..., 256)
45*
46*
47*
TT1H
TT1L
T1CKI High Synchronous, No Prescaler
0.5 TCY + 20
15
—
—
—
—
ns
ns
Time
Synchronous,
with Prescaler
Asynchronous
30
0.5 TCY + 20
15
—
—
—
—
—
—
ns
ns
ns
T1CKI Low Synchronous, No Prescaler
Time
Synchronous,
with Prescaler
Asynchronous
30
—
—
—
—
ns
TT1P
FT1
T1CKI Input Synchronous
Period
Greater of:
30 or TCY + 40
N
ns N = prescale value
(1, 2, 4, 8)
Asynchronous
60
—
—
—
—
ns
48
Timer1 Oscillator Input Frequency Range
(oscillator enabled by setting bit T1OSCEN)
32.768
kHz
49*
TCKEZTMR1 Delay from External Clock Edge to Timer
Increment
2 TOSC
—
7 TOSC
—
Timers in Sync
mode
*
These parameters are characterized but not tested.
†
Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
DS41202F-page 144
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 15-9:
CAPTURE/COMPARE/PWM TIMINGS (ECCP)
CCP1
(Capture mode)
CC01
CC02
CC03
Note:
Refer to Figure 15-3 for load conditions.
TABLE 15-6: CAPTURE/COMPARE/PWM REQUIREMENTS (ECCP)
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C ≤ TA ≤ +125°C
Param
No.
Sym
Characteristic
Min
Typ† Max Units
Conditions
CC01* TccL
CC02* TccH
CC03* TccP
CCP1 Input Low Time
CCP1 Input High Time
CCP1 Input Period
No Prescaler
0.5TCY + 20
20
—
—
—
—
—
—
—
—
—
—
ns
ns
ns
ns
With Prescaler
No Prescaler
With Prescaler
0.5TCY + 20
20
3TCY + 40
N
ns N = prescale
value (1, 4 or
16)
*
These parameters are characterized but not tested.
†
Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
© 2007 Microchip Technology Inc.
DS41202F-page 145
PIC16F684
TABLE 15-7: COMPARATOR SPECIFICATIONS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C ≤ TA ≤ +125°C
Param
No.
Sym
Characteristics
Min Typ†
Max
Units
Comments
CM01 VOS
CM02 VCM
CM03* CMRR
CM04* TRT
Input Offset Voltage
—
0
5.0
—
10
VDD – 1.5
—
mV (VDD - 1.5)/2
Input Common Mode Voltage
Common Mode Rejection Ratio
Response Time
V
+55
—
—
dB
Falling
Rising
150
200
—
600
ns
ns
μs
(NOTE 1)
—
1000
10
CM05* TMC2COV Comparator Mode Change to
Output Valid
—
*
These parameters are characterized but not tested.
†
Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Response time is measured with one comparator input at (VDD - 1.5)/2 - 100 mV to (VDD - 1.5)/2 + 20 mV.
TABLE 15-8: COMPARATOR VOLTAGE REFERENCE (CVREF) SPECIFICATIONS
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C
Param
Sym
No.
Characteristics
Min
Typ†
Max
Units
Comments
CV01* CLSB
Step Size(2)
Absolute Accuracy
—
—
VDD/24
VDD/32
—
—
V
V
Low Range (VRR = 1)
High Range (VRR = 0)
CV02* CACC
—
—
—
—
1/2
1/2
LSb Low Range (VRR = 1)
LSb High Range (VRR = 0)
CV03* CR
CV04* CST
Unit Resistor Value (R)
Settling Time(1)
—
—
2k
—
—
Ω
μs
10
*
These parameters are characterized but not tested.
†
Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note 1: Settling time measured while VRR = 1and VR<3:0> transitions from ‘0000’ to ‘1111’.
2: See Section 8.10 “Comparator Voltage Reference” for more information.
DS41202F-page 146
© 2007 Microchip Technology Inc.
PIC16F684
TABLE 15-9: PIC16F684 A/D CONVERTER (ADC) CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C
Param
No.
Sym
Characteristic
Min
Typ†
Max
Units
Conditions
AD01 NR
AD02 EIL
AD03 EDL
Resolution
—
—
—
—
10 bits
bit
Integral Error
—
—
1
1
LSb VREF = 5.12V
Differential Error
LSb No missing codes to 10 bits
VREF = 5.12V
AD04 EOFF Offset Error
AD07 EGN Gain Error
AD06 VREF Reference Voltage(3)
—
—
—
—
—
1
1
LSb VREF = 5.12V
LSb VREF = 5.12V
2.2
2.7
—
VDD
V
AD06A
Absolute minimum to ensure 1 LSb
accuracy
AD07 VAIN Full-Scale Range
VSS
—
—
—
VREF
10
V
AD08 ZAIN Recommended
Impedance of Analog
Voltage Source
kΩ
AD09* IREF
VREF Input Current(3)
10
—
—
—
1000
50
μA During VAIN acquisition.
Based on differential of VHOLD to VAIN.
μA During A/D conversion cycle.
*
These parameters are characterized but not tested.
†
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: Total Absolute Error includes integral, differential, offset and gain errors.
2: The A/D conversion result never decreases with an increase in the input voltage and has no missing
codes.
3: ADC VREF is from external VREF or VDD pin, whichever is selected as reference input.
4: When ADC is off, it will not consume any current other than leakage current. The power-down current
specification includes any such leakage from the ADC module.
© 2007 Microchip Technology Inc.
DS41202F-page 147
PIC16F684
TABLE 15-10: PIC16F684 A/D CONVERSION REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C
Param
No.
Sym
Characteristic
A/D Clock Period
Min
Typ†
Max Units
Conditions
AD130* TAD
1.6
3.0
—
—
9.0
9.0
μs TOSC-based, VREF ≥ 3.0V
μs TOSC-based, VREF full range
A/D Internal RC
Oscillator Period
ADCS<1:0> = 11(ADRC mode)
μs At VDD = 2.5V
3.0
1.6
—
6.0
4.0
11
9.0
6.0
—
μs At VDD = 5.0V
AD131 TCNV Conversion Time
(not including
TAD Set GO/DONE bit to new data in A/D
Result register
Acquisition Time)(1)
AD132* TACQ Acquisition Time
11.5
—
—
5
μs
μs
—
AD133* TAMP Amplifier Settling Time
AD134 TGO Q4 to A/D Clock Start
—
—
TOSC/2
—
—
TOSC/2 + TCY
—
—
If the A/D clock source is selected as
RC, a time of TCY is added before the
A/D clock starts. This allows the SLEEP
instruction to be executed.
*
These parameters are characterized but not tested.
†
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: ADRESH and ADRESL registers may be read on the following TCY cycle.
2: See Section 9.3 “A/D Acquisition Requirements” for minimum conditions.
DS41202F-page 148
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 15-10:
PIC16F684 A/D CONVERSION TIMING (NORMAL MODE)
BSF ADCON0, GO
AD134
1 TCY
(1)
(TOSC/2
)
AD131
Q4
AD130
A/D CLK
A/D Data
9
8
7
6
3
2
1
0
NEW_DATA
1 TCY
OLD_DATA
ADRES
ADIF
GO
DONE
Sampling Stopped
AD132
Sample
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the
SLEEPinstruction to be executed.
FIGURE 15-11:
PIC16F684 A/D CONVERSION TIMING (SLEEP MODE)
BSF ADCON0, GO
AD134
Q4
(1)
(TOSC/2 + TCY
)
1 TCY
AD131
AD130
A/D CLK
A/D Data
9
8
7
3
2
1
0
6
NEW_DATA
1 TCY
OLD_DATA
ADRES
ADIF
GO
DONE
Sampling Stopped
AD132
Sample
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the
SLEEPinstruction to be executed.
© 2007 Microchip Technology Inc.
DS41202F-page 149
PIC16F684
NOTES:
DS41202F-page 150
© 2007 Microchip Technology Inc.
PIC16F684
16.0 DC AND AC CHARACTERISTICS GRAPHS AND TABLES
The graphs and tables provided in this section are for design guidance and are not tested.
In some graphs or tables, the data presented are outside specified operating range (i.e., outside specified VDD
range). This is for information only and devices are ensured to operate properly only within the specified range.
Note: The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein are
not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore, outside the warranted range.
“Typical” represents the mean of the distribution at 25°C. “Maximum” or “minimum” represents
(mean + 3σ) or (mean - 3σ) respectively, where σ is a standard deviation, over each temperature range.
FIGURE 16-1:
TYPICAL IDD vs. FOSC OVER VDD (EC MODE)
3.5
Typical: Statistical Mean @25°C
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
5.5V
5.0V
4.0V
3.0V
2.0V
1 MHz
2 MHz
4 MHz
6 MHz
8 MHz
10 MHz 12 MHz 14 MHz 16 MHz 18 MHz 20 MHz
FOSC
© 2007 Microchip Technology Inc.
DS41202F-page 151
PIC16F684
FIGURE 16-2:
MAXIMUM IDD vs. FOSC OVER VDD (EC MODE)
4.0
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
5.5V
5.0V
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
4.0V
3.0V
2.0V
1 MHz
2 MHz
4 MHz
6 MHz
8 MHz
10 MHz 12 MHz 14 MHz 16 MHz 18 MHz 20 MHz
FOSC
FIGURE 16-3:
TYPICAL IDD vs. FOSC OVER VDD (HS MODE)
Typical IDD vs FOSC Over Vdd
4.0
Typical: Statistical Mean @25°C
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
4 MHz
10 MHz
16 MHz
20 MHz
FOSC
DS41202F-page 152
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-4:
MAXIMUM IDD vs. FOSC OVER VDD (HS MODE)
5.0
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
4 MHz
10 MHz
16 MHz
20 MHz
FOSC
FIGURE 16-5:
TYPICAL IDD vs. VDD OVER FOSC (XT MODE)
XT Mode
900
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
800
700
600
500
400
300
200
100
0
4 MHz
1 MHz
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
© 2007 Microchip Technology Inc.
DS41202F-page 153
PIC16F684
FIGURE 16-6:
MAXIMUM IDD vs. VDD OVER FOSC (XT MODE)
1,400
1,200
1,000
800
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
4 MHz
1 MHz
600
400
200
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-7:
TYPICAL IDD vs. VDD OVER FOSC (EXTRC MODE)
800
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
700
600
500
400
300
200
100
0
4 MHz
1 MHz
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
DS41202F-page 154
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-8:
MAXIMUM IDD vs. VDD OEVXETRRCFMOoSdCe(EXTRC MODE)
1,400
1,200
1,000
800
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
4 MHz
1 MHz
600
400
200
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-9:
IDD vs. VDD OVER FOSC (LFINTOSC MODE, 31 kHz)
LFINTOSC Mode, 31KHZ
80
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
70
60
50
40
30
20
10
0
Maximum
Typical
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
© 2007 Microchip Technology Inc.
DS41202F-page 155
PIC16F684
FIGURE 16-10:
IDD vs. VDD OVER FOSC (LP MODE)
70
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
60
50
40
30
20
10
0
32 kHz Maximum
32 kHz Typical
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-11:
TYPICAL IDD vs. FOSC OVER VDD (HFINTOSC MODE)
1,600
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
5.5V
1,400
1,200
1,000
800
5.0V
4.0V
3.0V
2.0V
600
400
200
0
125 kHz
250 kHz
500 kHz
1 MHz
2 MHz
4 MHz
8 MHz
FOSC
DS41202F-page 156
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-12:
MAXIMUM IDD vs. FOSC OVER VDD (HFINTOSC MODE)
HFINTOSC
2,000
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
5.5V
5.0V
1,800
1,600
1,400
1,200
1,000
800
4.0V
3.0V
600
2.0V
400
200
0
125 kHz
250 kHz
500 kHz
1 MHz
2 MHz
4 MHz
8 MHz
FOSC
FIGURE 16-13:
TYPICAL IPD vs. VDD (SLETEyPpiMcaOl DE, ALL PERIPHERALS DISABLED)
0.45
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
© 2007 Microchip Technology Inc.
DS41202F-page 157
PIC16F684
FIGURE 16-14:
MAXIMUM IPD vs. VDD (SLEEP MODE, ALL PERIPHERALS DISABLED)
18.0
Typical: Statistical Mean @25°C
16.0
14.0
12.0
10.0
8.0
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
Max. 125°C
6.0
4.0
Max. 85°C
3.5
2.0
0.0
2.0
2.5
3.0
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-15:
COMPARATOR IPD vs. VDD (BOTH COMPARATORS ENABLED)
180
160
140
120
100
80
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
Maximum
Typical
60
40
20
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
DS41202F-page 158
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-16:
BOR IPD vs. VDD OVER TEMPERATURE
160
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
140
120
100
80
Maximum
Typical
60
40
20
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-17:
TYPICAL WDT IPD vs. VDD OVER TEMPERATURE
Typical
3.0
Typical:StatisticalMean@25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
2.5
2.0
1.5
1.0
0.5
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
© 2007 Microchip Technology Inc.
DS41202F-page 159
PIC16F684
FIGURE 16-18:
MAXIMUM WDT IPD vs. VDD OVER TEMPERATURE
Maximum
25.0
20.0
15.0
10.0
5.0
Max. 125°C
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
Max. 85°C
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-19:
WDT PERIOD vs. VDD OVER TEMPERATURE
30
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
28
26
24
22
20
18
16
14
12
10
Max. (125°C)
Max. (85°C)
Typical
Minimum
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
DS41202F-page 160
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-20:
WDT PERIOD vs. TEMPERVAdTdU=R5EV OVER VDD (5.0V)
30
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
28
26
24
22
20
18
16
14
12
10
Maximum
Typical
Minimum
-40°C
25°C
85°C
125°C
Temperature (°C)
FIGURE 16-21:
CVREF IPD vs. VDD OVERHTigEhMRPaEngReATURE (HIGH RANGE)
140
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
120
100
80
60
40
20
0
Max. 125°C
Max. 85°C
Typical
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
© 2007 Microchip Technology Inc.
DS41202F-page 161
PIC16F684
FIGURE 16-22:
CVREF IPD vs. VDD OVER TEMPERATURE (LOW RANGE)
180
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
160
140
120
100
80
Max. 125°C
Max. 85°C
Typical
60
40
20
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-23:
VOL vs. IOL OVER TEMPERATURE (VDD = 3.0V)
(VDD = 3V, -40×C TO 125×C)
0.8
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Max. 125°C
Max. 85°C
Typical 25°C
Min. -40°C
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
IOL (mA)
DS41202F-page 162
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-24:
VOL vs. IOL OVER TEMPERATURE (VDD = 5.0V)
0.45
Typical: Statistical Mean @25°C
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
Max. 125°C
Max. 85°C
Typ. 25°C
Min. -40°C
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
IOL (mA)
FIGURE 16-25:
VOH vs. IOH OVER TEMPERATURE (VDD = 3.0V)
3.5
3.0
2.5
2.0
1.5
Max. -40°C
Typ. 25°C
Min. 125°C
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
1.0
0.5
0.0
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
-3.5
-4.0
IOH (mA)
© 2007 Microchip Technology Inc.
DS41202F-page 163
PIC16F684
FIGURE 16-26:
VOH vs. IOH OVER TEMPERATURE (VDD = 5.0V)
5.5
5.0
4.5
4.0
Max. -40°C
Typ. 25°C
Min. 125°C
Typical: Statistical Mean @25°C
3.5
3.0
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
-3.5
-4.0
-4.5
-5.0
IOH (mA)
FIGURE 16-27:
TTL INPUT THRESHOLD VIN vs. VDD OVER TEMPERATURE
1.7
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
1.5
1.3
1.1
0.9
0.7
0.5
Max. -40°C
Typ. 25°C
Min. 125°C
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
DS41202F-page 164
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-28:
SCHMITT TRIGGER INPUT THRESHOLD VIN vs. VDD OVER TEMPERATURE
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
VIH Max. 125°C
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
VIH Min. -40°C
VIL Max. -40°C
VIL Min. 125°C
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-29:
T1OSC IPD vs. VDD OVER TEMPERATURE (32 kHz)
45.0
Typical: Statistical Mean @25°C
40.0
35.0
30.0
25.0
20.0
15.0
10.0
5.0
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
Max. 125°C
Max. 85°C
Typ. 25°C
3.5
0.0
2.0
2.5
3.0
4.0
4.5
5.0
5.5
VDD (V)
© 2007 Microchip Technology Inc.
DS41202F-page 165
PIC16F684
FIGURE 16-30:
COMPARATOR RESPONSE TIME (RISING EDGE)
531
806
1000
900
800
700
Max. 125°C
Max. 85°C
VCM = VDD - 1.5V)/2
V+ input = VCM
V- input = Transition from VCM + 100MV to VCM - 20MV
Note:
600
500
400
300
200
100
Typ. 25°C
Min. -40°C
0
2.0
2.5
4.0
5.5
VDD (V)
FIGURE 16-31:
COMPARATOR RESPONSE TIME (FALLING EDGE)
1000
900
800
700
Max. 125°C
Max. 85°C
VCM = VDD - 1.5V)/2
600
500
400
300
200
100
0
Note:
V+ input = VCM
V- input = Transition from VCM - 100MV to VCM + 20MV
Typ. 25°C
Min. -40°C
2.0
2.5
4.0
5.5
VDD (V)
DS41202F-page 166
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-32:
LFINTOSC FREQUENCY vs. VDD OVER TEMPERATURE (31 kHz)
LFINTOSC 31Khz
45,000
40,000
35,000
30,000
25,000
20,000
15,000
10,000
5,000
Max. -40°C
Typ. 25°C
Min. 85°C
Min. 125°C
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-33:
ADC CLOCK PERIOD vs. VDD OVER TEMPERATURE
8
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
125°C
85°C
6
4
2
0
25°C
-40°C
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
© 2007 Microchip Technology Inc.
DS41202F-page 167
PIC16F684
FIGURE 16-34:
TYPICAL HFINTOSC START-UP TIMES vs. VDD OVER TEMPERATURE
16
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
14
85°C
12
25°C
10
-40°C
8
6
4
2
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-35:
MAXIMUM HFINTOSC START-UP TIMES vs. VDD OVER TEMPERATURE
-40C to +85C
25
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
20
15
10
5
85°C
25°C
-40°C
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
DS41202F-page 168
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-36:
MINIMUM HFINTOSC START-UP TIMES vs. VDD OVER TEMPERATURE
10
9
Typical: Statistical Mean @25°C
Maximum: Mean (Worst Case Temp) + 3σ
(-40°C to 125°C)
8
7
85°C
6
25°C
5
-40°C
4
3
2
1
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-37:
TYPICAL HFINTOSC FREQUENCY CHANGE vs. VDD (25°C)
5
4
3
2
1
0
-1
-2
-3
-4
-5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
© 2007 Microchip Technology Inc.
DS41202F-page 169
PIC16F684
FIGURE 16-38:
TYPICAL HFINTOSC FREQUENCY CHANGE OVER DEVICE VDD (85°C)
5
4
3
2
1
0
-1
-2
-3
-4
-5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
FIGURE 16-39:
TYPICAL HFINTOSC FREQUENCY CHANGE vs. VDD (125°C)
5
4
3
2
1
0
-1
-2
-3
-4
-5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
DS41202F-page 170
© 2007 Microchip Technology Inc.
PIC16F684
FIGURE 16-40:
TYPICAL HFINTOSC FREQUENCY CHANGE vs. VDD (-40°C)
5
4
3
2
1
0
-1
-2
-3
-4
-5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
© 2007 Microchip Technology Inc.
DS41202F-page 171
PIC16F684
NOTES:
DS41202F-page 172
© 2007 Microchip Technology Inc.
PIC16F684
17.0 PACKAGING INFORMATION
17.1 Package Marking Information
14-Lead PDIP
Example
Example
XXXXXXXXXXXXXX
XXXXXXXXXXXXXX
PIC16F684
e
3
-I/P
0510017
YYWWNNN
14-Lead SOIC (.150”)
XXXXXXXXXXX
XXXXXXXXXXX
PIC16F684-E
e
3
YYWWNNN
0510017
14-Lead TSSOP
Example
XXXXXXXX
YYWW
XXXX/ST
0510
NNN
017
16-Lead QFN
Example
XXXXXX
XXXXXX
YWWNNN
16F684-I
/ML
510017
e
3
Legend: XX...X Customer-specific information
Y
Year code (last digit of calendar year)
YY
Year code (last 2 digits of calendar year)
WW
NNN
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
e
3
Pb-free JEDEC designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator (
can be found on the outer packaging for this package.
*
)
3
e
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 PIC device marking consists of Microchip part number, year code, week code, and traceability
code. For PIC 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.
© 2007 Microchip Technology Inc.
DS41202F-page 173
PIC16F684
17.2 Package Details
The following sections give the technical details of the packages.
14-Lead Plastic Dual In-Line (P or PD) – 300 mil Body [PDIP]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
N
NOTE 1
E1
3
1
2
D
E
A2
A
L
c
A1
b1
b
e
eB
Units
INCHES
NOM
14
Dimension Limits
MIN
MAX
Number of Pins
Pitch
N
e
.100 BSC
–
Top to Seating Plane
A
–
.210
.195
–
Molded Package Thickness
Base to Seating Plane
Shoulder to Shoulder Width
Molded Package Width
Overall Length
A2
A1
E
.115
.015
.290
.240
.735
.115
.008
.045
.014
–
.130
–
.310
.250
.750
.130
.010
.060
.018
–
.325
.280
.775
.150
.015
.070
.022
.430
E1
D
Tip to Seating Plane
Lead Thickness
L
c
Upper Lead Width
b1
b
Lower Lead Width
Overall Row Spacing §
eB
Notes:
1. Pin 1 visual index feature may vary, but must be located with the hatched area.
2. § Significant Characteristic.
3. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" per side.
4. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Microchip Technology Drawing C04-005B
DS41202F-page 174
© 2007 Microchip Technology Inc.
PIC16F684
14-Lead Plastic Small Outline (SL or OD) – Narrow, 3.90 mm Body [SOIC]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
D
N
E
E1
NOTE 1
1
2
3
e
h
b
α
h
c
φ
A2
A
L
A1
β
L1
Units
MILLIMETERS
Dimension Limits
MIN
NOM
MAX
Number of Pins
Pitch
N
e
14
1.27 BSC
Overall Height
A
–
–
1.75
–
Molded Package Thickness
Standoff §
A2
A1
E
1.25
0.10
–
–
0.25
Overall Width
6.00 BSC
Molded Package Width
Overall Length
E1
D
h
3.90 BSC
8.65 BSC
Chamfer (optional)
Foot Length
0.25
0.40
–
0.50
1.27
L
–
Footprint
L1
φ
1.04 REF
Foot Angle
0°
0.17
0.31
5°
–
–
–
–
–
8°
Lead Thickness
Lead Width
c
0.25
0.51
15°
b
Mold Draft Angle Top
Mold Draft Angle Bottom
α
β
5°
15°
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. § Significant Characteristic.
3. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15 mm per side.
4. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
REF: Reference Dimension, usually without tolerance, for information purposes only.
Microchip Technology Drawing C04-065B
© 2007 Microchip Technology Inc.
DS41202F-page 175
PIC16F684
14-Lead Plastic Thin Shrink Small Outline (ST) – 4.4 mm Body [TSSOP]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
D
N
E
E1
NOTE 1
1
2
e
b
c
φ
A2
A
A1
L
L1
Units
MILLIMETERS
Dimension Limits
MIN
NOM
MAX
Number of Pins
Pitch
N
e
14
0.65 BSC
Overall Height
Molded Package Thickness
Standoff
A
–
–
1.20
1.05
0.15
A2
A1
E
0.80
0.05
1.00
–
Overall Width
Molded Package Width
Molded Package Length
Foot Length
6.40 BSC
E1
D
4.30
4.90
0.45
4.40
4.50
5.10
0.75
5.00
L
0.60
Footprint
L1
φ
1.00 REF
Foot Angle
0°
–
–
–
8°
Lead Thickness
Lead Width
c
0.09
0.20
0.30
b
0.19
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15 mm per side.
3. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
REF: Reference Dimension, usually without tolerance, for information purposes only.
Microchip Technology Drawing C04-087B
DS41202F-page 176
© 2007 Microchip Technology Inc.
PIC16F684
16-Lead Plastic Quad Flat, No Lead Package (ML) – 4x4x0.9 mm Body [QFN]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
D
D2
EXPOSED
PAD
e
E
E2
2
1
2
b
1
K
N
N
NOTE 1
L
TOP VIEW
BOTTOM VIEW
A3
A
A1
Units
MILLIMETERS
Dimension Limits
MIN
NOM
16
MAX
Number of Pins
N
e
Pitch
0.65 BSC
0.90
Overall Height
Standoff
A
0.80
0.00
1.00
0.05
A1
A3
E
0.02
Contact Thickness
Overall Width
Exposed Pad Width
Overall Length
Exposed Pad Length
Contact Width
Contact Length
0.20 REF
4.00 BSC
2.65
E2
D
2.50
2.80
4.00 BSC
2.65
D2
b
2.50
0.25
0.30
0.20
2.80
0.35
0.50
–
0.30
L
0.40
Contact-to-Exposed Pad
K
–
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. Package is saw singulated.
3. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
REF: Reference Dimension, usually without tolerance, for information purposes only.
Microchip Technology Drawing C04-127B
© 2007 Microchip Technology Inc.
DS41202F-page 177
PIC16F684
NOTES:
DS41202F-page 178
© 2007 Microchip Technology Inc.
PIC16F684
APPENDIX A: DATA SHEET
REVISION HISTORY
APPENDIX B: MIGRATING FROM
OTHER PIC®
DEVICES
Revision A
This discusses some of the issues in migrating from
other PIC devices to the PIC16F6XX Family of devices.
This is a new data sheet.
Revision B
B.1
PIC16F676 to PIC16F684
Rewrites of the Oscillator and Special Features of the
CPU Sections. General corrections to Figures and
formatting.
TABLE B-1:
Feature
FEATURE COMPARISON
PIC16F676
PIC16F684
Max Operating
Speed
20 MHz
20 MHz
Revision C
Revision D
Max Program
Memory (Words)
1024
2048
SRAM (bytes)
A/D Resolution
64
128
10-bit
256
Added Characterization Data. Updated Electrical
Specifications. Incorporated Golden Chapter Sections
for the following:
10-bit
128
Data EEPROM
(Bytes)
• Section 3.0 “Oscillator Module (With Fail-Safe
Clock Monitor)”
Timers (8/16-bit)
Oscillator Modes
Brown-out Reset
Internal Pull-ups
1/1
8
2/1
8
• Section 5.0 “Timer0 Module”
• Section 6.0 “Timer1 Module with Gate Control”
• Section 7.0 “Timer2 Module”
Y
Y
RA0/1/2/4/5 RA0/1/2/4/5,
MCLR
• Section 8.0 “Comparator Module”
• Section 9.0 “Analog-to-Digital Converter (ADC)
Module”
Interrupt-on-change RA0/1/2/3/4/5 RA0/1/2/3/4/5
Comparator
ECCP
1
N
N
2
Y
Y
• Section 11.0 “Enhanced Capture/Compare/PWM
(With Auto-Shutdown and Dead Band) Module”
Ultra Low-Power
Wake-Up
Revision E
Extended WDT
N
N
Y
Y
Updated Package Drawings; Replace PICmicro with
PIC.
Software Control
Option of WDT/BOR
INTOSC
Frequencies
4 MHz
N
32 kHz-
8 MHz
Revision F (03/2007)
Replaced Package Drawings (Rev. AM); Replaced
Development Support Section.
Clock Switching
Y
Note: This device has been designed to perform
to the parameters of its data sheet. It has
been tested to an electrical specification
designed to determine its conformance
with these parameters. Due to process
differences in the manufacture of this
device, this device may have different
performance characteristics than its earlier
version. These differences may cause this
device to perform differently in your
application than the earlier version of this
device.
© 2007 Microchip Technology Inc.
DS41202F-page 179
PIC16F684
NOTES:
DS41202F-page 180
© 2007 Microchip Technology Inc.
PIC16F684
INDEX
RA4 Pin ...................................................................... 37
RA5 Pin ...................................................................... 38
RC0 and RC1 Pins ..................................................... 41
RC2 and RC3 Pins ..................................................... 41
RC4 Pin ...................................................................... 42
RC5 Pin ...................................................................... 42
Resonator Operation .................................................. 22
Timer1 ........................................................................ 47
Timer2 ........................................................................ 53
TMR0/WDT Prescaler ................................................ 43
Watchdog Timer (WDT)............................................ 110
Brown-out Reset (BOR).................................................... 101
Associated................................................................ 102
Calibration ................................................................ 101
Specifications ........................................................... 143
Timing and Characteristics....................................... 142
A
A/D
Specifications.................................................... 147, 148
Absolute Maximum Ratings .............................................. 129
AC Characteristics
Industrial and Extended ............................................ 139
Load Conditions........................................................ 138
ADC .................................................................................... 65
Acquisition Requirements ........................................... 72
Associated registers.................................................... 74
Block Diagram............................................................. 65
Calculating Acquisition Time....................................... 72
Channel Selection....................................................... 66
Configuration............................................................... 66
Configuring Interrupt ................................................... 68
Conversion Clock........................................................ 66
Conversion Procedure ................................................ 68
Internal Sampling Switch (RSS) Impedance................ 72
Interrupts..................................................................... 67
Operation .................................................................... 68
Operation During Sleep .............................................. 68
Port Configuration....................................................... 66
Reference Voltage (VREF)........................................... 66
Result Formatting........................................................ 67
Source Impedance...................................................... 72
Special Event Trigger.................................................. 68
Starting an A/D Conversion ........................................ 67
ADCON0 Register............................................................... 70
ADCON1 Register............................................................... 70
ADRESH Register (ADFM = 0)........................................... 71
ADRESH Register (ADFM = 1)........................................... 71
ADRESL Register (ADFM = 0)............................................ 71
ADRESL Register (ADFM = 1)............................................ 71
Analog Input Connection Considerations............................ 57
Analog-to-Digital Converter. See ADC
C
C Compilers
MPLAB C18.............................................................. 126
MPLAB C30.............................................................. 126
Calibration Bits.................................................................... 99
Capture Module. See Enhanced Capture/
Compare/PWM (ECCP)
Capture/Compare/PWM (CCP)
Associated registers w/ Capture/Compare/PWM ....... 96
Capture Mode............................................................. 80
CCP1 Pin Configuration ............................................. 80
Compare Mode........................................................... 81
CCP1 Pin Configuration ..................................... 81
Software Interrupt Mode............................... 80, 81
Special Event Trigger......................................... 81
Timer1 Mode Selection................................. 80, 81
Prescaler .................................................................... 80
PWM Mode................................................................. 82
Duty Cycle .......................................................... 83
Effects of Reset.................................................. 84
Example PWM Frequencies and
ANSEL Register.................................................................. 32
Assembler
MPASM Assembler................................................... 126
Resolutions, 20 MHZ.................................. 83
Example PWM Frequencies and
B
Resolutions, 8 MHz .................................... 83
Operation in Sleep Mode.................................... 84
Setup for Operation ............................................ 84
System Clock Frequency Changes .................... 84
PWM Period ............................................................... 83
Setup for PWM Operation .......................................... 84
CCP1CON (Enhanced) Register ........................................ 79
Clock Sources
External Modes........................................................... 21
EC ...................................................................... 21
HS ...................................................................... 22
LP....................................................................... 22
OST .................................................................... 21
RC ...................................................................... 23
XT....................................................................... 22
Internal Modes............................................................ 23
Frequency Selection........................................... 25
HFINTOSC ......................................................... 23
HFINTOSC/LFINTOSC Switch Timing............... 25
INTOSC.............................................................. 23
INTOSCIO .......................................................... 23
LFINTOSC.......................................................... 25
Clock Switching .................................................................. 27
CMCON0 Register.............................................................. 61
Block Diagrams
(CCP) Capture Mode Operation ................................. 80
ADC ............................................................................ 65
ADC Transfer Function ............................................... 73
Analog Input Model............................................... 57, 73
CCP PWM................................................................... 82
Clock Source............................................................... 19
Comparator 1.............................................................. 56
Comparator 2.............................................................. 56
Comparator Modes ..................................................... 58
Compare ..................................................................... 81
Crystal Operation........................................................ 22
External RC Mode....................................................... 23
Fail-Safe Clock Monitor (FSCM)................................. 29
In-Circuit Serial Programming Connections.............. 114
Interrupt Logic........................................................... 107
MCLR Circuit............................................................. 100
On-Chip Reset Circuit................................................. 99
PIC16F684.................................................................... 5
PWM (Enhanced)........................................................ 85
RA0 Pins..................................................................... 35
RA1 Pins..................................................................... 36
RA2 Pin....................................................................... 36
RA3 Pin....................................................................... 37
© 2007 Microchip Technology Inc.
DS41202F-page 181
PIC16F684
CMCON1 Register ..............................................................62
Code Examples
Reading ...................................................................... 77
Write Verify................................................................. 77
Writing ........................................................................ 77
A/D Conversion...........................................................69
Assigning Prescaler to Timer0 ....................................44
Assigning Prescaler to WDT .......................................44
Changing Between Capture Prescalers......................80
Data EEPROM Read ..................................................77
Data EEPROM Write ..................................................77
Indirect Addressing .....................................................19
Initializing PORTA.......................................................31
Initializing PORTC.......................................................40
Saving Status and W Registers in RAM ...................109
Ultra Low-Power Wake-Up Initialization......................34
Write Verify .................................................................77
Code Protection ................................................................113
Comparator .........................................................................55
C2OUT as T1 Gate .....................................................62
Configurations.............................................................58
Interrupts.....................................................................59
Operation ....................................................................59
Operation During Sleep ..............................................60
Overview .....................................................................55
Response Time...........................................................59
Synchronizing COUT w/Timer1 ..................................62
Comparator Module
Effects of Reset
PWM mode................................................................. 84
Electrical Specifications.................................................... 129
Enhanced Capture/Compare/PWM .................................... 79
Enhanced Capture/Compare/PWM (ECCP)
Enhanced PWM Mode................................................ 85
Auto-Restart ....................................................... 94
Auto-shutdown.................................................... 93
Direction Change in Full-Bridge Output Mode.... 91
Full-Bridge Application........................................ 89
Full-Bridge Mode ................................................ 89
Half-Bridge Application....................................... 88
Half-Bridge Application Examples ...................... 95
Half-Bridge Mode................................................ 88
Output Relationships (Active-High and
Active-Low)................................................ 86
Output Relationships Diagram............................ 87
Programmable Dead-Band Delay....................... 95
Shoot-through Current........................................ 95
Start-up Considerations...................................... 92
Specifications ........................................................... 145
Timer Resources ........................................................ 79
Errata.................................................................................... 4
Associated Registers ..................................................64
Comparator Voltage Reference (CVREF)
F
Response Time...........................................................59
Comparator Voltage Reference (CVREF) ............................63
Effects of a Reset........................................................60
Specifications............................................................146
Comparators
C2OUT as T1 Gate .....................................................49
Effects of a Reset........................................................60
Specifications............................................................146
Compare Module. See Enhanced Capture/
Fail-Safe Clock Monitor ...................................................... 29
Fail-Safe Condition Clearing....................................... 29
Fail-Safe Detection ..................................................... 29
Fail-Safe Operation..................................................... 29
Reset or Wake-up from Sleep .................................... 29
Firmware Instructions ....................................................... 115
Fuses. See Configuration Bits
G
Compare/PWM (ECCP)
General Purpose Register File ............................................. 8
CONFIG Register................................................................98
Configuration Bits................................................................97
CPU Features .....................................................................97
Customer Change Notification Service .............................187
Customer Notification Service...........................................187
Customer Support.............................................................187
I
ID Locations...................................................................... 113
In-Circuit Debugger........................................................... 114
In-Circuit Serial Programming (ICSP)............................... 114
Indirect Addressing, INDF and FSR registers..................... 19
Instruction Format............................................................. 115
Instruction Set................................................................... 115
ADDLW..................................................................... 117
ADDWF..................................................................... 117
ANDLW..................................................................... 117
ANDWF..................................................................... 117
BCF .......................................................................... 117
BSF........................................................................... 117
BTFSC...................................................................... 117
BTFSS ...................................................................... 118
CALL......................................................................... 118
CLRF ........................................................................ 118
CLRW ....................................................................... 118
CLRWDT .................................................................. 118
COMF ....................................................................... 118
DECF........................................................................ 118
DECFSZ ................................................................... 119
GOTO ....................................................................... 119
INCF ......................................................................... 119
INCFSZ..................................................................... 119
IORLW...................................................................... 119
IORWF...................................................................... 119
D
Data EEPROM Memory
Associated Registers ..................................................78
Code Protection .................................................... 75, 78
Data Memory.........................................................................7
DC and AC Characteristics
Graphs and Tables ...................................................151
DC Characteristics
Extended and Industrial ............................................135
Industrial and Extended ............................................131
Development Support .......................................................125
Device Overview ...................................................................5
E
ECCP. See Enhanced Capture/Compare/PWM
ECCPAS Register...............................................................93
EEADR Register .................................................................75
EECON1 Register...............................................................76
EECON2 Register...............................................................76
EEDAT Register..................................................................75
EEPROM Data Memory
Avoiding Spurious Write..............................................78
DS41202F-page 182
© 2007 Microchip Technology Inc.
PIC16F684
MOVF........................................................................ 120
MOVLW .................................................................... 120
MOVWF .................................................................... 120
NOP .......................................................................... 120
RETFIE ..................................................................... 121
RETLW ..................................................................... 121
RETURN................................................................... 121
RLF ........................................................................... 122
RRF........................................................................... 122
SLEEP ...................................................................... 122
SUBLW ..................................................................... 122
SUBWF..................................................................... 123
SWAPF ..................................................................... 123
XORLW..................................................................... 123
XORWF..................................................................... 123
Summary Table......................................................... 116
INTCON Register................................................................ 15
Internal Oscillator Block
HS............................................................................... 19
INTOSC...................................................................... 19
INTOSCIO .................................................................. 19
LFINTOSC.................................................................. 19
LP ............................................................................... 19
RC .............................................................................. 19
RCIO........................................................................... 19
XT............................................................................... 19
Oscillator Parameters ....................................................... 140
Oscillator Specifications.................................................... 139
Oscillator Start-up Timer (OST)
Specifications ........................................................... 143
Oscillator Switching
Fail-Safe Clock Monitor .............................................. 29
Two-Speed Clock Start-up ......................................... 27
OSCTUNE Register............................................................ 24
P
P1A/P1B/P1C/P1D.See Enhanced Capture/
INTOSC
Compare/PWM (ECCP).............................................. 85
Packaging......................................................................... 173
Marking..................................................................... 173
PDIP Details ............................................................. 174
PCL and PCLATH............................................................... 19
Stack........................................................................... 19
PCON Register........................................................... 18, 102
PICSTART Plus Development Programmer..................... 128
PIE1 Register ..................................................................... 16
Pin Diagram
Specifications............................................ 140, 141
Internal Sampling Switch (RSS) Impedance........................ 72
Internet Address................................................................ 187
Interrupts........................................................................... 106
ADC ............................................................................ 68
Associated Registers ................................................ 108
Comparator................................................................. 59
Context Saving.......................................................... 109
Data EEPROM Memory Write .................................... 76
Interrupt-on-Change.................................................... 32
PORTA Interrupt-on-Change .................................... 107
RA2/INT .................................................................... 106
Timer0....................................................................... 107
TMR1 .......................................................................... 49
INTOSC Specifications ............................................. 140, 141
IOCA Register..................................................................... 33
PDIP, SOIC, TSSOP .................................................... 2
QFN.............................................................................. 3
Pinout Descriptions
PIC16F684 ................................................................... 6
PIR1 Register ..................................................................... 17
PORTA ............................................................................... 31
Additional Pin Functions............................................. 32
ANSEL Register ................................................. 32
Interrupt-on-Change ........................................... 32
Ultra Low-Power Wake-Up........................... 32, 34
Weak Pull-up ...................................................... 32
Associated registers ................................................... 39
Pin Descriptions and Diagrams .................................. 35
RA0............................................................................. 35
RA1............................................................................. 35
RA2............................................................................. 36
RA3............................................................................. 37
RA4............................................................................. 37
RA5............................................................................. 38
Specifications ........................................................... 141
PORTA Register................................................................. 31
PORTC ............................................................................... 40
Associated registers ................................................... 42
P1A/P1B/P1C/P1D.See Enhanced Capture/
Compare/PWM (ECCP)...................................... 40
Specifications ........................................................... 141
PORTC Register................................................................. 40
Power-Down Mode (Sleep)............................................... 112
Power-on Reset (POR)..................................................... 100
Power-up Timer (PWRT).................................................. 100
Specifications ........................................................... 143
Precision Internal Oscillator Parameters .......................... 141
Prescaler
L
Load Conditions................................................................ 138
M
MCLR................................................................................ 100
Internal...................................................................... 100
Memory Organization............................................................ 7
Data .............................................................................. 7
Data EEPROM Memory.............................................. 75
Program ........................................................................ 7
Microchip Internet Web Site.............................................. 187
Migrating from other PICmicro Devices ............................ 179
MPLAB ASM30 Assembler, Linker, Librarian ................... 126
MPLAB ICD 2 In-Circuit Debugger ................................... 127
MPLAB ICE 2000 High-Performance Universal
In-Circuit Emulator .................................................... 127
MPLAB Integrated Development Environment Software .. 125
MPLAB PM3 Device Programmer .................................... 127
MPLAB REAL ICE In-Circuit Emulator System................. 127
MPLINK Object Linker/MPLIB Object Librarian ................ 126
O
OPCODE Field Descriptions............................................. 115
OPTION Register.......................................................... 14, 45
OSCCON Register.............................................................. 20
Oscillator
Associated registers.............................................. 30, 51
Oscillator Module ................................................................ 19
EC............................................................................... 19
HFINTOSC.................................................................. 19
Shared WDT/Timer0................................................... 44
Switching Prescaler Assignment ................................ 44
Program Memory.................................................................. 7
Map and Stack.............................................................. 7
© 2007 Microchip Technology Inc.
DS41202F-page 183
PIC16F684
Programming, Device Instructions ....................................115
PWM Mode. See Enhanced Capture/Compare/PWM ........85
PWM1CON Register...........................................................96
Thermal Considerations.................................................... 137
Time-out Sequence .......................................................... 102
Timer0................................................................................. 43
Associated Registers.................................................. 45
External Clock............................................................. 44
Interrupt ...................................................................... 45
Operation.............................................................. 43, 47
Specifications ........................................................... 144
T0CKI ......................................................................... 44
Timer1................................................................................. 47
Associated registers ................................................... 51
Asynchronous Counter Mode ..................................... 48
Reading and Writing........................................... 48
Interrupt ...................................................................... 49
Modes of Operation .................................................... 47
Operation During Sleep .............................................. 49
Oscillator..................................................................... 48
Prescaler .................................................................... 48
Specifications ........................................................... 144
Timer1 Gate
R
Reader Response .............................................................188
Read-Modify-Write Operations..........................................115
Registers
ADCON0 (ADC Control 0) ..........................................70
ADCON1 (ADC Control 1) ..........................................70
ADRESH (ADC Result High) with ADFM = 0).............71
ADRESH (ADC Result High) with ADFM = 1).............71
ADRESL (ADC Result Low) with ADFM = 0)..............71
ADRESL (ADC Result Low) with ADFM = 1)..............71
ANSEL (Analog Select)...............................................32
CCP1CON (Enhanced CCP1 Control)........................79
CMCON0 (Comparator Control 0) ..............................61
CMCON1 (Comparator Control 1) ..............................62
CONFIG (Configuration Word)....................................98
Data Memory Map ........................................................8
ECCPAS (Enhanced CCP Auto-shutdown Control) ...93
EEADR (EEPROM Address) ......................................75
EECON1 (EEPROM Control 1)...................................76
EECON2 (EEPROM Control 2)...................................76
EEDAT (EEPROM Data) ............................................75
INTCON (Interrupt Control).........................................15
IOCA (Interrupt-on-Change PORTA) ..........................33
OPTION_REG (OPTION) ..................................... 14, 45
OSCCON (Oscillator Control) .....................................20
OSCTUNE (Oscillator Tuning)....................................24
PCON (Power Control Register).................................18
PCON (Power Control) .............................................102
PIE1 (Peripheral Interrupt Enable 1)...........................16
PIR1 (Peripheral Interrupt Register 1) ........................17
PORTA........................................................................31
PORTC .......................................................................40
PWM1CON (Enhanced PWM Control) .......................96
Reset Values.............................................................104
Reset Values (Special Registers) .............................105
Special Function Registers ...........................................8
Special Register Summary .........................................11
STATUS......................................................................13
T1CON........................................................................50
T2CON........................................................................54
TRISA (Tri-State PORTA)...........................................31
TRISC (Tri-State PORTC) ..........................................40
VRCON (Voltage Reference Control) .........................63
WDTCON (Watchdog Timer Control)........................111
WPUA (Weak Pull-Up PORTA) ..................................33
Reset...................................................................................99
Revision History ................................................................179
Inverting Gate..................................................... 49
Selecting Source .......................................... 49, 62
Synchronizing COUT w/Timer1.......................... 62
TMR1H Register......................................................... 47
TMR1L Register.......................................................... 47
Timer2
Associated registers ................................................... 54
Timers
Timer1
T1CON ............................................................... 50
Timer2
T2CON ............................................................... 54
Timing Diagrams
A/D Conversion......................................................... 149
A/D Conversion (Sleep Mode).................................. 149
Brown-out Reset (BOR)............................................ 142
Brown-out Reset Situations ...................................... 101
CLKOUT and I/O ...................................................... 141
Clock Timing............................................................. 139
Comparator Output..................................................... 55
Enhanced Capture/Compare/PWM (ECCP)............. 145
Fail-Safe Clock Monitor (FSCM)................................. 30
Full-Bridge PWM Output............................................. 90
Half-Bridge PWM Output ...................................... 88, 95
INT Pin Interrupt ....................................................... 108
Internal Oscillator Switch Timing ................................ 26
PWM Auto-shutdown
Auto-restart Enabled........................................... 94
Firmware Restart................................................ 94
PWM Direction Change .............................................. 91
PWM Direction Change at Near 100% Duty Cycle..... 92
PWM Output (Active-High) ......................................... 86
PWM Output (Active-Low).......................................... 87
Reset, WDT, OST and Power-up Timer................... 142
Time-out Sequence
S
Shoot-through Current ........................................................95
Sleep
Power-Down Mode ...................................................112
Wake-up....................................................................112
Wake-up Using Interrupts .........................................112
Software Simulator (MPLAB SIM).....................................126
Special Event Trigger..........................................................68
Special Function Registers ...................................................8
STATUS Register................................................................13
Case 1 .............................................................. 103
Case 2 .............................................................. 103
Case 3 .............................................................. 103
Timer0 and Timer1 External Clock ........................... 144
Two Speed Start-up.................................................... 28
Wake-up from Interrupt............................................. 113
Timing Parameter Symbology .......................................... 138
TRISA Register................................................................... 31
TRISC Register................................................................... 40
Two-Speed Clock Start-up Mode........................................ 27
T
T1CON Register..................................................................50
T2CON Register..................................................................54
DS41202F-page 184
© 2007 Microchip Technology Inc.
PIC16F684
U
Ultra Low-Power Wake-Up ....................................... 6, 32, 34
V
Voltage Reference. See Comparator Voltage Reference
(CVREF)
Voltage References
Associated Registers .................................................. 64
VREF. SEE ADC Reference Voltage
W
Wake-up Using Interrupts ................................................. 112
Watchdog Timer (WDT) .................................................... 110
Associated Registers ................................................ 111
Clock Source............................................................. 110
Modes ....................................................................... 110
Period........................................................................ 110
Specifications............................................................ 143
WDTCON Register ........................................................... 111
WPUA Register................................................................... 33
WWW Address.................................................................. 187
WWW, On-Line Support ....................................................... 4
© 2007 Microchip Technology Inc.
DS41202F-page 185
PIC16F684
NOTES:
DS41202F-page 186
© 2007 Microchip Technology Inc.
PIC16F684
THE MICROCHIP WEB SITE
CUSTOMER SUPPORT
Microchip provides online support via our WWW site at
www.microchip.com. This web site is used as a means
to make files and information easily available to
customers. Accessible by using your favorite Internet
browser, the web site contains the following
information:
Users of Microchip products can receive assistance
through several channels:
• Distributor or Representative
• Local Sales Office
• Field Application Engineer (FAE)
• Technical Support
• Product Support – Data sheets and errata,
application notes and sample programs, design
resources, user’s guides and hardware support
documents, latest software releases and archived
software
• Development Systems Information Line
Customers
should
contact
their
distributor,
representative or field application engineer (FAE) for
support. Local sales offices are also available to help
customers. A listing of sales offices and locations is
included in the back of this document.
• General Technical Support – Frequently Asked
Questions (FAQ), technical support requests,
online discussion groups, Microchip consultant
program member listing
Technical support is available through the web site
at: http://support.microchip.com
• Business of Microchip – Product selector and
ordering guides, latest Microchip press releases,
listing of seminars and events, listings of
Microchip sales offices, distributors and factory
representatives
CUSTOMER CHANGE NOTIFICATION
SERVICE
Microchip’s customer notification service helps keep
customers current on Microchip products. Subscribers
will receive e-mail notification whenever there are
changes, updates, revisions or errata related to a
specified product family or development tool of interest.
To register, access the Microchip web site at
www.microchip.com, click on Customer Change
Notification and follow the registration instructions.
© 2007 Microchip Technology Inc.
DS41202F-page 187
PIC16F684
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip prod-
uct. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation
can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150.
Please list the following information, and use this outline to provide us with your comments about this document.
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PIC16F684
DS41202F
Literature Number:
Device:
Questions:
1. What are the best features of this document?
2. How does this document meet your hardware and software development needs?
3. Do you find the organization of this document easy to follow? If not, why?
4. What additions to the document do you think would enhance the structure and subject?
5. What deletions from the document could be made without affecting the overall usefulness?
6. Is there any incorrect or misleading information (what and where)?
7. How would you improve this document?
DS41202F-page 188
© 2007 Microchip Technology Inc.
PIC16F684
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)
PIC16F684-E/P 301 = Extended Temp., PDIP
package, 20 MHz, QTP pattern #301
b)
PIC16F684-I/SO
package, 20 MHz
= Industrial Temp., SOIC
Device:
PIC16F684, PIC16F684T(1)
VDD range 2.0V to 5.5V
Temperature
Range:
I
E
=
=
-40°C to +85°C (Industrial)
-40°C to +125°C (Extended)
Package:
ML
P
SL
ST
=
Quad Flat No Leads (QFN)
Plastic DIP
14-lead Small Outline (3.90 mm)
Thin Shrink Small Outline (4.4 mm)
=
=
=
Note 1:
T
=
in tape and reel TSSOP, SOIC and
QFN packages only.
Pattern:
QTP, SQTPSM or ROM Code; Special Requirements
(blank otherwise)
© 2007 Microchip Technology Inc.
DS41202F-page 189
WORLDWIDE SALES AND SERVICE
AMERICAS
ASIA/PACIFIC
ASIA/PACIFIC
EUROPE
Corporate Office
Asia Pacific Office
Suites 3707-14, 37th Floor
Tower 6, The Gateway
Habour City, Kowloon
Hong Kong
Tel: 852-2401-1200
Fax: 852-2401-3431
India - Bangalore
Tel: 91-80-4182-8400
Fax: 91-80-4182-8422
Austria - Wels
Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support:
http://support.microchip.com
Web Address:
www.microchip.com
Denmark - Copenhagen
Tel: 45-4450-2828
Fax: 45-4485-2829
India - New Delhi
Tel: 91-11-4160-8631
Fax: 91-11-4160-8632
France - Paris
Tel: 33-1-69-53-63-20
Fax: 33-1-69-30-90-79
India - Pune
Tel: 91-20-2566-1512
Fax: 91-20-2566-1513
Australia - Sydney
Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
Atlanta
Duluth, GA
Tel: 678-957-9614
Fax: 678-957-1455
Germany - Munich
Tel: 49-89-627-144-0
Fax: 49-89-627-144-44
Japan - Yokohama
Tel: 81-45-471- 6166
Fax: 81-45-471-6122
China - Beijing
Tel: 86-10-8528-2100
Fax: 86-10-8528-2104
Italy - Milan
Tel: 39-0331-742611
Fax: 39-0331-466781
Korea - Gumi
Tel: 82-54-473-4301
Fax: 82-54-473-4302
Boston
China - Chengdu
Tel: 86-28-8665-5511
Fax: 86-28-8665-7889
Westborough, MA
Tel: 774-760-0087
Fax: 774-760-0088
Netherlands - Drunen
Tel: 31-416-690399
Fax: 31-416-690340
Korea - Seoul
China - Fuzhou
Tel: 86-591-8750-3506
Fax: 86-591-8750-3521
Tel: 82-2-554-7200
Fax: 82-2-558-5932 or
82-2-558-5934
Chicago
Itasca, IL
Tel: 630-285-0071
Fax: 630-285-0075
Spain - Madrid
Tel: 34-91-708-08-90
Fax: 34-91-708-08-91
China - Hong Kong SAR
Tel: 852-2401-1200
Fax: 852-2401-3431
Malaysia - Penang
Tel: 60-4-646-8870
Fax: 60-4-646-5086
Dallas
Addison, TX
Tel: 972-818-7423
Fax: 972-818-2924
UK - Wokingham
Tel: 44-118-921-5869
Fax: 44-118-921-5820
China - Qingdao
Tel: 86-532-8502-7355
Fax: 86-532-8502-7205
Philippines - Manila
Tel: 63-2-634-9065
Fax: 63-2-634-9069
Detroit
Farmington Hills, MI
Tel: 248-538-2250
Fax: 248-538-2260
China - Shanghai
Tel: 86-21-5407-5533
Fax: 86-21-5407-5066
Singapore
Tel: 65-6334-8870
Fax: 65-6334-8850
Kokomo
Kokomo, IN
Tel: 765-864-8360
Fax: 765-864-8387
China - Shenyang
Tel: 86-24-2334-2829
Fax: 86-24-2334-2393
Taiwan - Hsin Chu
Tel: 886-3-572-9526
Fax: 886-3-572-6459
China - Shenzhen
Tel: 86-755-8203-2660
Fax: 86-755-8203-1760
Taiwan - Kaohsiung
Tel: 886-7-536-4818
Fax: 886-7-536-4803
Los Angeles
Mission Viejo, CA
Tel: 949-462-9523
Fax: 949-462-9608
China - Shunde
Tel: 86-757-2839-5507
Fax: 86-757-2839-5571
Taiwan - Taipei
Tel: 886-2-2500-6610
Fax: 886-2-2508-0102
Santa Clara
Santa Clara, CA
Tel: 408-961-6444
Fax: 408-961-6445
China - Wuhan
Tel: 86-27-5980-5300
Fax: 86-27-5980-5118
Thailand - Bangkok
Tel: 66-2-694-1351
Fax: 66-2-694-1350
Toronto
Mississauga, Ontario,
Canada
Tel: 905-673-0699
Fax: 905-673-6509
China - Xian
Tel: 86-29-8833-7250
Fax: 86-29-8833-7256
12/08/06
DS41202F-page 190
© 2007 Microchip Technology Inc.
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