PIC12CE673-10E/JM [MICROCHIP]

8-Pin, 8-Bit CMOS Microcontroller with A/D Converter; 8引脚, 8位CMOS微控制器与A / D转换器
PIC12CE673-10E/JM
型号: PIC12CE673-10E/JM
厂家: MICROCHIP    MICROCHIP
描述:

8-Pin, 8-Bit CMOS Microcontroller with A/D Converter
8引脚, 8位CMOS微控制器与A / D转换器

转换器 微控制器
文件: 总129页 (文件大小:1827K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
PIC12C67X  
8-Pin, 8-Bit CMOS Microcontroller with A/D Converter  
and EEPROM Data Memory  
Devices Included in this Data Sheet:  
Pin Diagrams:  
PDIP, SOIC, Windowed CERDIP  
• PIC12C671  
• PIC12C672  
• PIC12CE673  
• PIC12CE674  
VDD  
1
VSS  
8
7
6
5
GP5/OSC1/CLKIN  
GP4/OSC2/AN3/  
CLKOUT  
GP3/MCLR/VPP  
GP0/AN0  
2
3
GP1/AN1/VREF  
GP2/T0CKI/AN2/  
INT  
4
Note: Throughout this data sheet PIC12C67X  
refers to the PIC12C671, PIC12C672,  
PIC12CE673 and PIC12CE674.  
PIC12CE67X refers to PIC12CE673 and  
PIC12CE674.  
PDIP, Windowed CERDIP  
VSS  
VDD  
1
2
3
4
8
7
6
5
High-Performance RISC CPU:  
GP0/AN0  
GP5/OSC1/CLKIN  
GP4/OSC2/AN3/  
CLKOUT  
GP1/AN1/VREF  
GP2/T0CKI/AN2/  
INT  
• Only 35 single word instructions to learn  
GP3/MCLR/VPP  
• All instructions are single cycle (400 ns) except for  
program branches which are two-cycle  
• Operating speed: DC - 10 MHz clock input  
DC - 400 ns instruction cycle  
Special Microcontroller Features:  
• In-Circuit Serial Programming (ICSP™)  
Memory  
• Internal 4 MHz oscillator with programmable calibration  
Device  
Data  
RAM  
Data  
EEPROM  
• Selectable clockout  
• Power-on Reset (POR)  
Program  
• Power-up Timer (PWRT) and Oscillator Start-up  
Timer (OST)  
• Watchdog Timer (WDT) with its own on-chip RC  
oscillator for reliable operation  
• Programmable code protection  
PIC12C671  
PIC12C672  
1024 x 14  
2048 x 14  
128 x 8  
128 x 8  
128 x 8  
128 x 8  
PIC12CE673 1024 x 14  
PIC12CE674 2048 x 14  
16 x 8  
16 x 8  
• 14-bit wide instructions  
• 8-bit wide data path  
• Interrupt capability  
• Special function hardware registers  
• 8-level deep hardware stack  
• Power saving SLEEP mode  
• Interrupt-on-pin change (GP0, GP1, GP3)  
• Internal pull-ups on I/O pins (GP0, GP1, GP3)  
• Internal pull-up on MCLR pin  
• Selectable oscillator options:  
- INTRC: Precision internal 4 MHz oscillator  
- EXTRC: External low-cost RC oscillator  
• Direct, indirect and relative addressing modes for  
data and instructions  
Peripheral Features:  
- XT:  
- HS:  
- LP:  
Standard crystal/resonator  
High speed crystal/resonator  
Power saving, low frequency crystal  
• Four-channel, 8-bit A/D converter  
• 8-bit real time clock/counter (TMR0) with 8-bit  
programmable prescaler  
CMOS Technology:  
• 1,000,000 erase/write cycle EEPROM data  
memory  
• EEPROM data retention > 40 years  
• Low-power, high-speed CMOS EPROM/EEPROM  
technology  
• Fully static design  
• Wide operating voltage range 2.5V to 5.5V  
• Commercial, Industrial and Extended  
temperature ranges  
• Low power consumption  
< 2 mA @ 5V, 4 MHz  
15 µA typical @ 3V, 32 kHz  
< 1 µA typical standby current  
1999 Microchip Technology Inc.  
DS30561B-page 1  
PIC12C67X  
Table of Contents  
1.0 General Description ...................................................................................................................................................................... 3  
2.0 PIC12C67X Device Varieties ........................................................................................................................................................ 5  
3.0 Architectural Overview .................................................................................................................................................................. 7  
4.0 Memory Organization.................................................................................................................................................................. 11  
5.0 I/O Port........................................................................................................................................................................................ 25  
6.0 EEPROM Peripheral Operation .................................................................................................................................................. 33  
7.0 Timer0 Module ............................................................................................................................................................................ 39  
8.0 Analog-to-Digital Converter (A/D) Module................................................................................................................................... 45  
9.0 Special Features of the CPU....................................................................................................................................................... 53  
10.0 Instruction Set Summary............................................................................................................................................................. 69  
11.0 Development Support ................................................................................................................................................................. 83  
12.0 Electrical Specifications .............................................................................................................................................................. 89  
13.0 DC and AC Characteristics....................................................................................................................................................... 109  
14.0 Packaging Information .............................................................................................................................................................. 115  
Appendix A:Compatibility ................................................................................................................................................................... 119  
Appendix B:Code for Accessing EEPROM Data Memory ................................................................................................................. 119  
Index .................................................................................................................................................................................................. 121  
On-Line Support................................................................................................................................................................................. 125  
Reader Response .............................................................................................................................................................................. 126  
PIC12C67X Product Identification System ........................................................................................................................................ 127  
To Our Valued Customers  
Most Current Data Sheet  
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Errata  
An errata sheet may exist for current devices, describing minor operational differences (from the data sheet) and recommended  
workarounds. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revi-  
sion of silicon and revision of document to which it applies.  
To determine if an errata sheet exists for a particular device, please check with one of the following:  
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Corrections to this Data Sheet  
We constantly strive to improve the quality of all our products and documentation. We have spent a great deal of time to ensure  
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We appreciate your assistance in making this a better document.  
DS30561B-page 2  
1999 Microchip Technology Inc.  
PIC12C67X  
A highly reliable Watchdog Timer with its own on-chip  
RC oscillator provides protection against software  
lock-up.  
1.0  
GENERAL DESCRIPTION  
The PIC12C67X devices are low-cost, high-perfor-  
mance, CMOS, fully-static, 8-bit microcontrollers with  
integrated analog-to-digital (A/D) converter and  
EEPROM data memory (EEPROM on PIC12CE67X  
versions only).  
A UV erasable windowed package version is ideal for  
code development, while the cost-effective One-Time-  
Programmable (OTP) version is suitable for production  
in any volume. The customer can take full advantage of  
Microchip’s price leadership in OTP microcontrollers,  
while benefiting from the OTP’s flexibility.  
All PICmicro® microcontrollers employ an advanced  
RISC architecture. The PIC12C67X microcontrollers  
have enhanced core features, eight-level deep stack,  
and multiple internal and external interrupt sources.  
The separate instruction and data buses of the Harvard  
architecture allow a 14-bit wide instruction word with  
the separate 8-bit wide data. The two stage instruction  
pipeline allows all instructions to execute in a single  
cycle, except for program branches, which require two  
cycles. A total of 35 instructions (reduced instruction  
set) are available. Additionally, a large register set gives  
some of the architectural innovations used to achieve a  
very high performance.  
1.1  
Applications  
The PIC12C67X series fits perfectly in applications  
ranging from personal care appliances and security  
systems to low-power remote transmitters/receivers.  
The EPROM technology makes customizing applica-  
tion programs (transmitter codes, appliance settings,  
receiver frequencies, etc.) extremely fast and conve-  
nient, while the EEPROM data memory (PIC12CE67X  
only) technology allows for the changing of calibration  
factors and security codes. The small footprint pack-  
ages, for through hole or surface mounting, make this  
microcontroller series perfect for applications with  
space limitations. Low-cost, low-power, high perfor-  
mance, ease of use and I/O flexibility make the  
PIC12C67X series very versatile even in areas where  
no microcontroller use has been considered before  
(i.e., timer functions, replacement of "glue" logic and  
PLD’s in larger systems, coprocessor applications).  
PIC12C67X microcontrollers typically achieve a 2:1  
code compression and a 4:1 speed improvement over  
other 8-bit microcontrollers in their class.  
The PIC12C67X devices have 128 bytes of RAM, 16  
bytes of EEPROM data memory (PIC12CE67X only), 5  
I/O pins and 1 input pin. In addition a timer/counter is  
available. Also a 4-channel, high-speed, 8-bit A/D is  
provided. The 8-bit resolution is ideally suited for appli-  
cations requiring low-cost analog interface, (i.e.,  
thermostat control, pressure sensing, etc.)  
1.2  
Family and Upward Compatibility  
The PIC12C67X products are compatible with other  
members of the 14-bit PIC16CXXX families.  
The PIC12C67X devices have special features to  
reduce external components, thus reducing cost,  
enhancing system reliability and reducing power con-  
sumption. The Power-On Reset (POR), Power-up  
Timer (PWRT), and Oscillator Start-up Timer (OST)  
eliminate the need for external reset circuitry. There are  
five oscillator configurations to choose from, including  
INTRC precision internal oscillator mode and the  
power-saving LP (Low Power) oscillator mode. Power-  
saving SLEEP mode, Watchdog Timer and code  
protection features improve system cost, power and  
reliability. The SLEEP (power-down) feature provides a  
power-saving mode. The user can wake-up the chip  
from SLEEP through several external and internal  
interrupts and resets.  
1.3  
Development Support  
The PIC12C67X devices are supported by a full-  
featured macro assembler, a software simulator, an in-  
circuit emulator, a low-cost development programmer  
and a full-featured programmer. A “C” compiler and  
fuzzy logic support tools are also available.  
1999 Microchip Technology Inc.  
DS30561B-page 3  
PIC12C67X  
TABLE 1-1:  
PIC12C67X & PIC12CE67X FAMILY OF DEVICES  
PIC12C671 PIC12LC671 PIC12C672 PIC12LC672 PIC12CE673 PIC12LCE673 PIC12CE674 PIC12LCE674  
Maximum  
10  
10  
10  
10  
10  
10  
10  
10  
Frequency  
of Operation  
(MHz)  
Clock  
EPROM  
Program  
Memory  
1024 x 14  
128  
1024 x 14  
128  
2048 x 14  
128  
2048 x 14  
128  
1024 x 14  
128  
1024 x 14  
128  
2048 x 14  
128  
2048 x 14  
128  
Memory  
RAM Data  
Memory  
(bytes)  
EEPROM  
Data Memory  
(bytes)  
16  
16  
16  
16  
Timer  
Module(s)  
TMR0  
4
TMR0  
4
TMR0  
4
TMR0  
4
TMR0  
4
TMR0  
4
TMR0  
4
TMR0  
4
Peripherals  
A/D Con-  
verter (8-bit)  
Channels  
Wake-up  
from SLEEP  
on pin  
Yes  
4
Yes  
4
Yes  
4
Yes  
4
Yes  
4
Yes  
4
Yes  
4
Yes  
4
change  
Interrupt  
Sources  
I/O Pins  
5
5
5
5
5
5
5
5
Features  
Input Pins  
1
1
1
1
1
1
1
1
Internal  
Pull-ups  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
In-Circuit  
Serial  
Programming  
Yes  
35  
Yes  
35  
Yes  
35  
Yes  
35  
Yes  
35  
Yes  
35  
Yes  
35  
Yes  
35  
Number of  
Instructions  
Voltage  
3.0V - 5.5V 2.5V - 5.5V  
3.0V - 5.5V 2.5V - 5.5V  
3.0V - 5.5V 2.5V - 5.5V  
3.0V - 5.5V 2.5V - 5.5V  
Range (Volts)  
Packages  
8-pin DIP,  
JW, SOIC  
8-pin DIP,  
JW, SOIC  
8-pin DIP,  
JW, SOIC  
8-pin DIP,  
JW, SOIC  
8-pin DIP,  
JW  
8-pin DIP,  
JW  
8-pin DIP,  
JW  
8-pin DIP,  
JW  
All PIC12C67X devices have Power-on Reset, selectable Watchdog Timer, selectable code protect and high I/O current capability.  
All PIC12C67X devices use serial programming with data pin GP0 and clock pin GP1.  
DS30561B-page 4  
1999 Microchip Technology Inc.  
PIC12C67X  
2.3  
Quick-Turn-Programming (QTP)  
Devices  
2.0  
PIC12C67X DEVICE VARIETIES  
A variety of frequency ranges and packaging options  
are available. Depending on application and production  
requirements, the proper device option can be selected  
using the information in the PIC12C67X Product Iden-  
tification System section at the end of this data sheet.  
When placing orders, please use that page of the data  
sheet to specify the correct part number.  
Microchip offers a QTP Programming Service for fac-  
tory production orders. This service is made available  
for users who choose not to program a medium to high  
quantity of units and whose code patterns have stabi-  
lized. The devices are identical to the OTP devices, but  
with all EPROM locations and configuration options  
already programmed by the factory. Certain code and  
prototype verification procedures apply before produc-  
tion shipments are available. Please contact your local  
Microchip Technology sales office for more details.  
For example, the PIC12C67X device “type” is indicated  
in the device number:  
1. C, as in PIC12C671. These devices have  
EPROM type memory and operate over the  
standard voltage range.  
2.4  
Serialized Quick-Turn Programming  
(SQTPSM) Devices  
2. LC, as in PIC12LC671. These devices have  
EPROM type memory and operate over an  
extended voltage range.  
Microchip offers a unique programming service where  
a few user-defined locations in each device are pro-  
grammed with different serial numbers. The serial num-  
bers may be random, pseudo-random, or sequential.  
3. CE, as in PIC12CE674. These devices have  
EPROM type memory, EEPROM data memory  
and operate over the standard voltage range.  
Serial programming allows each device to have a  
unique number which can serve as an entry-code,  
password, or ID number.  
4. LCE, as in PIC12LCE674. These devices have  
EPROM type memory, EEPROM data memory  
and operate over an extended voltage range.  
2.1  
UV Erasable Devices  
The UV erasable version, offered in windowed pack-  
age, is optimal for prototype development and pilot pro-  
grams.  
The UV erasable version can be erased and repro-  
grammed to any of the configuration modes.  
Microchip's PICSTART Plus and PRO MATE pro-  
grammers both support the PIC12C67X. Third party  
programmers also are available; refer to the Microchip  
Third Party Guide for a list of sources.  
Note: Please note that erasing the device will  
also erase the pre-programmed internal  
calibration value for the internal oscillator.  
The calibration value must be saved prior  
to erasing the part.  
2.2  
One-Time-Programmable (OTP)  
Devices  
The availability of OTP devices is especially useful for  
customers who need the flexibility for frequent code  
updates and small volume applications.  
The OTP devices, packaged in plastic packages, per-  
mit the user to program them once. In addition to the  
program memory, the configuration bits must also be  
programmed.  
1999 Microchip Technology Inc.  
DS30561B-page 5  
PIC12C67X  
NOTES:  
DS30561B-page 6  
1999 Microchip Technology Inc.  
PIC12C67X  
The PIC12C67X can directly or indirectly address its  
register files or data memory. All special function regis-  
ters, including the program counter, are mapped in the  
data memory. The PIC12C67X has an orthogonal  
(symmetrical) instruction set that makes it possible to  
carry out any operation on any register using any  
addressing mode. This symmetrical nature and lack of  
‘special optimal situations’ make programming with the  
PIC12C67X simple yet efficient. In addition, the learn-  
ing curve is reduced significantly.  
3.0  
ARCHITECTURAL OVERVIEW  
The high performance of the PIC12C67X family can be  
attributed to a number of architectural features com-  
monly found in RISC microprocessors. To begin with,  
the PIC12C67X uses a Harvard architecture, in which  
program and data are accessed from separate memo-  
ries using separate buses. This improves bandwidth  
over traditional von Neumann architecture in which pro-  
gram and data are fetched from the same memory  
using the same bus. Separating program and data  
buses also allow instructions to be sized differently than  
the 8-bit wide data word. Instruction opcodes are 14-  
bits wide making it possible to have all single word  
instructions. A 14-bit wide program memory access  
bus fetches a 14-bit instruction in a single instruction  
cycle. A two-stage pipeline overlaps fetch and execu-  
tion of instructions (Example 3-1). Consequently, all  
instructions (35) execute in a single cycle (400 ns @ 10  
MHz) except for program branches.  
PIC12C67X devices contain an 8-bit ALU and working  
register. The ALU is a general purpose arithmetic unit.  
It performs arithmetic and Boolean functions between  
the data in the working register and any register file.  
The ALU is 8-bits wide and capable of addition, sub-  
traction, shift and logical operations. Unless otherwise  
mentioned, arithmetic operations are two's comple-  
ment in nature. In two-operand instructions, typically  
one operand is the working register (W register). The  
other operand is a file register or an immediate con-  
stant. In single operand instructions, the operand is  
either the W register or a file register.  
The table below lists program memory (EPROM), data  
memory (RAM), and non-volatile memory (EEPROM)  
for each PIC12C67X device.  
The W register is an 8-bit working register used for ALU  
operations. It is not an addressable register.  
EEPROM  
Data  
Memory  
Program RAM Data  
Device  
Memory  
Memory  
Depending on the instruction executed, the ALU may  
affect the values of the Carry (C), Digit Carry (DC), and  
Zero (Z) bits in the STATUS register. The C and DC bits  
operate as a borrow bit and a digit borrow out bit,  
respectively, in subtraction. See the SUBLWand SUBWF  
instructions for examples.  
PIC12C671  
PIC12C672  
PIC12CE673  
PIC12CE674  
1K x 14  
2K x 14  
1K x 14  
2K x 14  
128 x 8  
128 x 8  
128 x 8  
128 x 8  
16x8  
16x8  
1999 Microchip Technology Inc.  
DS30561B-page 7  
PIC12C67X  
FIGURE 3-1: PIC12C67X BLOCK DIAGRAM  
Device  
Program Memory  
Data Memory (RAM)  
Non-Volatile Memory (EEPROM)  
PIC12C671  
PIC12C672  
PIC12CE673  
PIC12CE674  
1K x 14  
2K x 14  
1K x 14  
2K x 14  
128 x 8  
128 x 8  
128 x 8  
128 x 8  
16 x 8  
16 x 8  
13  
8
GPIO  
Data Bus  
Program Counter  
GP0/AN0  
GP1/AN1/VREF  
GP2/T0CKI/AN2/INT  
GP3/MCLR/VPP  
GP4/OSC2/AN3/CLKOUT  
EPROM  
Program  
Memory  
RAM  
8 Level Stack  
(13 bit)  
128 bytes  
File  
Registers  
GP5/OSC1/CLKIN  
Program  
Bus  
14  
RAM Addr (1)  
9
Addr MUX  
Instruction reg  
Indirect  
Addr  
7
Direct Addr  
8
16x8  
EEPROM  
Data  
FSR reg  
PIC12CE673  
PIC12CE674  
Memory  
STATUS reg  
8
3
MUX  
Power-up  
Timer  
Instruction  
Decode &  
Control  
Oscillator  
Start-up Timer  
ALU  
Watchdog  
Timer  
8
Timing  
Generation  
OSC1/CLKIN  
OSC2/CLKOUT  
Power-on  
Reset  
W reg  
Internal  
4 MHz Clock  
Timer0  
MCLR  
VDD, VSS  
A/D  
Note 1: Higher order bits are from the STATUS Register.  
DS30561B-page 8  
1999 Microchip Technology Inc.  
PIC12C67X  
TABLE 3-1:  
Name  
PIC12C67X PINOUT DESCRIPTION  
I/O/P Buffer  
DIP Pin #  
Description  
Type  
Type  
GP0/AN0  
7
6
I/O  
TTL/ST Bi-directional I/O port/serial programming data/analog input 0.  
Can be software programmed for internal weak pull-up and  
interrupt-on-pin change. This buffer is a Schmitt Trigger input  
when used in serial programming mode.  
GP1/AN1/VREF  
I/O  
TTL/ST Bi-directional I/O port/serial programming clock/analog input 1/  
voltage reference. Can be software programmed for internal  
weak pull-up and interrupt-on-pin change. This buffer is a  
Schmitt Trigger input when used in serial programming mode.  
GP2/T0CKI/AN2/INT  
GP3/MCLR/VPP  
5
4
I/O  
I
ST  
Bi-directional I/O port/analog input 2. Can be configured as  
T0CKI or external interrupt.  
TTL/ST Input port/master clear (reset) input/programming voltage  
input. When configured as MCLR, this pin is an active low  
reset to the device. Voltage on MCLR/VPP must not exceed  
VDD during normal device operation. Can be software pro-  
grammed for internal weak pull-up and interrupt-on-pin  
change. Weak pull-up always on if configured as MCLR . This  
buffer is Schmitt Trigger when in MCLR mode.  
GP4/OSC2/AN3/CLKOUT  
GP5/OSC1/CLKIN  
3
2
I/O  
I/O  
TTL  
Bi-directional I/O port/oscillator crystal output/analog input 3.  
Connections to crystal or resonator in crystal oscillator mode  
(HS, XT and LP modes only, GPIO in other modes). In EXTRC  
and INTRC modes, the pin output can be configured to CLK-  
OUT, which has 1/4 the frequency of OSC1 and denotes the  
instruction cycle rate.  
TTL/ST Bi-directional IO port/oscillator crystal input/external clock  
source input (GPIO in INTRC mode only, OSC1 in all other  
oscillator modes). Schmitt trigger input for EXTRC oscillator  
mode.  
VDD  
1
P
Positive supply for logic and I/O pins.  
Ground reference for logic and I/O pins.  
VSS  
8
P
Legend: I = input, O = output, I/O = input/output, P = power, — = not used, TTL = TTL input,  
ST = Schmitt Trigger input.  
1999 Microchip Technology Inc.  
DS30561B-page 9  
PIC12C67X  
3.1  
Clocking Scheme/Instruction Cycle  
3.2  
Instruction Flow/Pipelining  
The clock input (from OSC1) is internally divided by  
four to generate four non-overlapping quadrature  
clocks, namely Q1, Q2, Q3 and Q4. Internally, the pro-  
gram counter (PC) is incremented every Q1, and the  
instruction is fetched from the program memory and  
latched into the instruction register in Q4. The instruc-  
tion is decoded and executed during the following Q1  
through Q4. The clocks and instruction execution flow  
is shown in Figure 3-2.  
An “Instruction Cycle” consists of four Q cycles (Q1,  
Q2, Q3 and Q4). The instruction fetch and execute  
are pipelined such that fetch takes one instruction  
cycle, while decode and execute takes another  
instruction cycle. However, due to the pipelining, each  
instruction effectively executes in one cycle. If an  
instruction causes the program counter to change  
(i.e., GOTO), then two cycles are required to complete  
the instruction (Example 3-1).  
A fetch cycle begins with the program counter (PC)  
incrementing in Q1.  
In the execution cycle, the fetched instruction is  
latched into the “Instruction Register" (IR) in cycle  
Q1. This instruction is then decoded and executed  
during the Q2, Q3, and Q4 cycles. Data memory is  
read during Q2 (operand read) and written during Q4  
(destination write).  
FIGURE 3-2: CLOCK/INSTRUCTION CYCLE  
Q2  
Q3  
Q4  
Q2  
Q3  
Q4  
Q2  
Q3  
Q4  
Q1  
Q1  
Q1  
OSC1  
Q1  
Q2  
Internal  
phase  
clock  
Q3  
Q4  
PC  
PC  
PC+1  
PC+2  
OSC2/CLKOUT  
(EXTRC and  
INTRC modes)  
Fetch INST (PC)  
Execute INST (PC-1)  
Fetch INST (PC+1)  
Execute INST (PC)  
Fetch INST (PC+2)  
Execute INST (PC+1)  
EXAMPLE 3-1: INSTRUCTION PIPELINE FLOW  
TCY0  
TCY1  
TCY2  
TCY3  
TCY4  
TCY5  
1. MOVLW 55h  
2. MOVWF GPIO  
3. CALL SUB_1  
Fetch 1  
Execute 1  
Fetch 2  
Execute 2  
Fetch 3  
Execute 3  
Fetch 4  
4. BSF  
GPIO, BIT3 (Forced NOP)  
Flush  
5. Instruction @ address SUB_1  
Fetch SUB_1 Execute SUB_1  
All instructions are single cycle, except for any program branches. These take two cycles since the fetched  
instruction is “flushed” from the pipeline while the new instruction is being fetched and then executed.  
DS30561B-page 10  
1999 Microchip Technology Inc.  
PIC12C67X  
4.2  
Data Memory Organization  
4.0  
MEMORY ORGANIZATION  
The data memory is partitioned into two banks, which  
contain the General Purpose Registers and the Special  
Function Registers. Bit RP0 is the bank select bit.  
4.1  
Program Memory Organization  
The PIC12C67X has a 13-bit program counter capable  
of addressing an 8K x 14 program memory space.  
RP0 (STATUS<5>) = 1 Bank 1  
RP0 (STATUS<5>) = 0 Bank 0  
For the PIC12C671 and the PIC12CE673, the first 1K x  
14 (0000h-03FFh) is implemented.  
Each Bank extends up to 7Fh (128 bytes). The lower  
locations of each Bank are reserved for the Special  
Function Registers. Above the Special Function Regis-  
ters are General Purpose Registers implemented as  
static RAM. Both Bank 0 and Bank 1 contain Special  
Function Registers. Some "high use" Special Function  
Registers from Bank 0 are mirrored in Bank 1 for code  
reduction and quicker access.  
For the PIC12C672 and the PIC12CE674, the first 2K  
x 14 (0000h-07FFh) is implemented. Accessing a loca-  
tion above the physically implemented address will  
cause a wraparound. The reset vector is at 0000h and  
the interrupt vector is at 0004h.  
FIGURE 4-1: PIC12C67X PROGRAM  
MEMORY MAP AND STACK  
Also note that F0h through FFh on the PIC12C67X is  
mapped into Bank 0 registers 70h-7Fh as common  
RAM.  
PC<12:0>  
CALL, RETURN  
RETFIE, RETLW  
13  
4.2.1  
GENERAL PURPOSE REGISTER FILE  
The register file can be accessed either directly or indi-  
rectly through the File Select Register FSR  
(Section 4.5).  
Stack Level 1  
Stack Level 8  
Reset Vector  
0000h  
Peripheral  
Interrupt Vector  
0004h  
0005h  
On-Chip Program  
Memory  
03FFh  
0400h  
(PIC12C672 and  
PIC12CE674 only)  
07FFh  
0800h  
1FFFh  
1999 Microchip Technology Inc.  
DS30561B-page 11  
PIC12C67X  
4.2.2  
SPECIAL FUNCTION REGISTERS  
FIGURE 4-2: PIC12C67X REGISTER FILE  
MAP  
The Special Function Registers are registers used by  
the CPU and Peripheral Modules for controlling the  
desired operation of the device. These registers are  
implemented as static RAM.  
File  
Address  
File  
Address  
00h  
01h  
02h  
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  
INDF(1)  
TMR0  
PCL  
INDF(1)  
OPTION  
PCL  
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  
The Special Function Registers can be classified into  
two sets (core and peripheral). Those registers associ-  
ated with the “core” functions are described in this sec-  
tion, and those related to the operation of the peripheral  
features are described in the section of that peripheral  
feature.  
STATUS  
FSR  
STATUS  
FSR  
GPIO  
TRIS  
PCLATH  
INTCON  
PIR1  
PCLATH  
INTCON  
PIE1  
PCON  
OSCCAL  
ADRES  
ADCON0  
ADCON1  
A0h  
General  
Purpose  
Register  
BFh  
C0h  
General  
Purpose  
Register  
EFh  
F0h  
70h  
7Fh  
Mapped  
in Bank 0  
FFh  
Bank 0  
Bank 1  
Unimplemented data memory locations, read  
as ’0’.  
Note 1: Not a physical register.  
DS30561B-page 12  
1999 Microchip Technology Inc.  
PIC12C67X  
TABLE 4-1:  
PIC12C67X SPECIAL FUNCTION REGISTER SUMMARY  
Value on  
Power-on  
Reset  
Value on  
all other  
Resets(3)  
Address  
Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
Bank 0  
00h(1)  
01h  
INDF  
TMR0  
PCL  
STATUS  
FSR  
GPIO  
Addressing this location uses contents of FSR to address data memory (not a physical register)  
Timer0 module’s register  
0000 0000 0000 0000  
xxxx xxxx uuuu uuuu  
0000 0000 0000 0000  
0001 1xxx 000q quuu  
xxxx xxxx uuuu uuuu  
11xx xxxx 11uu uuuu  
02h(1)  
03h(1)  
04h(1)  
05h  
Program Counter's (PC) Least Significant Byte  
IRP(4)  
RP1(4)  
RP0  
TO  
PD  
Z
DC  
C
Indirect data memory address pointer  
SCL(5)  
SDA(5)  
GP5  
GP4  
GP3  
GP2  
GP1  
GP0  
06h  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
07h  
08h  
09h  
0Ah(1,2) PCLATH  
T0IE  
Write Buffer for the upper 5 bits of the Program Counter  
---0 0000 ---0 0000  
0000 000x 0000 000u  
-0-- ---- -0-- ----  
0Bh(1)  
0Ch  
0Dh  
0Eh  
0Fh  
10h  
11h  
12h  
13h  
14h  
15h  
16h  
17h  
18h  
19h  
1Ah  
1Bh  
1Ch  
1Dh  
1Eh  
1Fh  
INTCON  
GIE  
PEIE  
ADIF  
INTE  
GPIE  
T0IF  
INTF  
GPIF  
PIR1  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
A/D Result Register  
ADRES  
ADCON0  
xxxx xxxx uuuu uuuu  
0000 0000 0000 0000  
ADCS1  
ADCS0  
reserved  
CHS1  
CHS0  
GO/DONE reserved  
ADON  
Legend: x= unknown, u= unchanged, q= value depends on condition, - = unimplemented read as ’0’.  
Shaded locations are unimplemented, read as ‘0’.  
Note 1: These registers can be addressed from either bank.  
2: The upper byte of the program counter is not directly accessible. PCLATH is a holding register for the PC<12:8> whose con-  
tents are transferred to the upper byte of the program counter.  
3: Other (non power-up) resets include external reset through MCLR and Watchdog Timer Reset.  
4: The IRP and RP1 bits are reserved on the PIC12C67X; always maintain these bits clear.  
5: The SCL (GP7) and SDA (GP6) bits are unimplemented on the PIC12C671/672 and read as ’0’.  
1999 Microchip Technology Inc.  
DS30561B-page 13  
PIC12C67X  
TABLE 4-1:  
PIC12C67X SPECIAL FUNCTION REGISTER SUMMARY (CONT.)  
Value on  
Power-on  
Reset  
Value on  
all other  
Resets(3)  
Address  
Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
Bank 1  
80h(1)  
81h  
INDF  
OPTION  
PCL  
STATUS  
FSR  
TRIS  
Addressing this location uses contents of FSR to address data memory (not a physical register)  
0000 0000 0000 0000  
1111 1111 1111 1111  
0000 0000 0000 0000  
0001 1xxx 000q quuu  
xxxx xxxx uuuu uuuu  
--11 1111 --11 1111  
GPPU  
Program Counter’s (PC) Least Significant Byte  
IRP(4) RP1(4)  
RP0 TO  
Indirect data memory address pointer  
INTEDG  
T0CS  
T0SE  
PSA  
PS2  
PS1  
PS0  
82h(1)  
83h(1)  
84h(1)  
85h  
PD  
Z
DC  
C
GPIO Data Direction Register  
86h  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
87h  
88h  
89h  
8Ah(1,2) PCLATH  
T0IE  
Write Buffer for the upper 5 bits of the PC  
---0 0000 ---0 0000  
0000 000x 0000 000u  
-0-- ---- -0-- ----  
8Bh(1)  
8Ch  
8Dh  
8Eh  
8Fh  
90h  
91h  
92h  
93h  
94h  
95h  
96h  
97h  
98h  
99h  
9Ah  
9Bh  
9Ch  
9Dh  
9Eh  
9Fh  
INTCON  
GIE  
PEIE  
ADIE  
INTE  
GPIE  
T0IF  
INTF  
GPIF  
PIE1  
Unimplemented  
PCON  
POR  
---- --0- ---- --u-  
0111 00-- uuuu uu--  
OSCCAL  
CAL3  
CAL2  
CAL1  
CAL0  
CALFST  
CALSLW  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
Unimplemented  
ADCON1  
PCFG2  
PCFG1  
PCFG0  
---- -000 ---- -000  
Legend: x= unknown, u= unchanged, q= value depends on condition, - = unimplemented read as ’0’.  
Shaded locations are unimplemented, read as ‘0’.  
Note 1: These registers can be addressed from either bank.  
2: The upper byte of the program counter is not directly accessible. PCLATH is a holding register for the PC<12:8> whose con-  
tents are transferred to the upper byte of the program counter.  
3: Other (non power-up) resets include external reset through MCLR and Watchdog Timer Reset.  
4: The IRP and RP1 bits are reserved on the PIC12C67X; always maintain these bits clear.  
5: The SCL (GP7) and SDA (GP6) bits are unimplemented on the PIC12C671/672 and read as ’0’.  
DS30561B-page 14  
1999 Microchip Technology Inc.  
PIC12C67X  
4.2.2.1  
STATUS REGISTER  
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 the Z, C or DC bits from the STATUS Register.  
For other instructions, not affecting any status bits, see  
the "Instruction Set Summary."  
The STATUS Register, shown in Register 4-1, contains  
the arithmetic status of the ALU, the RESET status and  
the bank select bits for data memory.  
The STATUS Register can be the destination for any  
instruction, as with 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 (STATUS<7:6>) are not  
used by the PIC12C67X and should be  
maintained clear. Use of these bits as  
general purpose R/W bits is NOT recom-  
mended, since this may affect upward  
compatibility with future products.  
2: The C and DC bits operate as a borrow  
and digit borrow bit, respectively, in sub-  
traction. See the SUBLW and SUBWF  
instructions for examples.  
For example, CLRF STATUSwill clear the upper three  
bits and set the Z bit. This leaves the STATUS Register  
as 000u u1uu(where u= unchanged).  
REGISTER 4-1:  
STATUS REGISTER (ADDRESS 03h, 83h)  
Reserved Reserved R/W-0  
R-1  
TO  
R-1  
PD  
R/W-x  
Z
R/W-x  
DC  
R/W-x  
C
IRP  
bit7  
RP1  
RP0  
R
= Readable bit  
W = Writable bit  
bit0  
U
= Unimplemented bit,  
read as ‘0’  
- n = Value at POR reset  
bit 7:  
IRP: Register Bank Select bit (used for indirect addressing)  
1= Bank 2, 3 (100h - 1FFh)  
0= Bank 0, 1 (00h - FFh)  
The IRP bit is reserved; always maintain this bit clear.  
bit 6-5: RP<1:0>: Register Bank Select bits (used for direct addressing)  
11= Bank 3 (180h - 1FFh)  
10= Bank 2 (100h - 17Fh)  
01= Bank 1 (80h - FFh)  
00= Bank 0 (00h - 7Fh)  
Each bank is 128 bytes. The RP1 bit is reserved; always maintain this bit clear.  
bit 4:  
bit 3:  
bit 2:  
bit 1:  
bit 0:  
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  
C: Carry/borrow bit (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: 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 or low order bit of  
the source register.  
1999 Microchip Technology Inc.  
DS30561B-page 15  
PIC12C67X  
4.2.2.2  
OPTION REGISTER  
Note: To achieve a 1:1 prescaler assignment for  
the TMR0 register, assign the prescaler to  
the Watchdog Timer by setting bit PSA  
(OPTION<3>).  
The OPTION Register is a readable and writable regis-  
ter, which contains various control bits to configure the  
TMR0/WDT prescaler, the External INT Interrupt,  
TMR0 and the weak pull-ups on GPIO.  
REGISTER 4-2:  
OPTION REGISTER (ADDRESS 81h)  
R/W-1  
GPPU  
R/W-1  
INTEDG  
R/W-1  
T0CS  
R/W-1  
T0SE  
R/W-1  
PSA  
R/W-1  
PS2  
R/W-1  
PS1  
R/W-1  
PS0  
R
= Readable bit  
W = Writable bit  
U
bit7  
bit0  
= Unimplemented bit,  
read as ‘0’  
- n = Value at POR reset  
bit 7:  
bit 6:  
bit 5:  
bit 4:  
bit 3:  
GPPU: Weak Pull-up Enable  
1= Weak pull-ups disabled  
0= Weak pull-ups enabled (GP0, GP1, GP3)  
INTEDG: Interrupt Edge  
1= Interrupt on rising edge of GP2/T0CKI/AN2/INT pin  
0= Interrupt on falling edge of GP2/T0CKI/AN2/INT pin  
T0CS: TMR0 Clock Source Select bit  
1= Transition on GP2/T0CKI/AN2/INT pin  
0= Internal instruction cycle clock (CLKOUT)  
T0SE: TMR0 Source Edge Select bit  
1= Increment on high-to-low transition on GP2/T0CKI/AN2/INT pin  
0= Increment on low-to-high transition on GP2/T0CKI/AN2/INT pin  
PSA: Prescaler Assignment bit  
1= Prescaler is assigned to the WDT  
0= Prescaler is assigned to the Timer0 module  
bit 2-0: PS<2:0>: Prescaler Rate Select bits  
Bit Value  
TMR0 Rate WDT Rate  
000  
001  
010  
011  
100  
101  
110  
111  
1 : 2  
1 : 4  
1 : 8  
1 : 16  
1 : 32  
1 : 64  
1 : 128  
1 : 256  
1 : 1  
1 : 2  
1 : 4  
1 : 8  
1 : 16  
1 : 32  
1 : 64  
1 : 128  
DS30561B-page 16  
1999 Microchip Technology Inc.  
PIC12C67X  
4.2.2.3  
INTCON REGISTER  
Note: Interrupt flag bits get set when an interrupt  
condition occurs, regardless of the state of  
its corresponding enable bit or the global  
enable bit, GIE (INTCON<7>).  
The INTCON Register is a readable and writable regis-  
ter, which contains various enable and flag bits for the  
TMR0 Register overflow, GPIO port change and exter-  
nal GP2/INT pin interrupts.  
REGISTER 4-3:  
INTCON REGISTER (ADDRESS 0Bh, 8Bh)  
R/W-0  
GIE  
R/W-0  
PEIE  
R/W-0  
T0IE  
R/W-0  
INTE  
R/W-0  
GPIE  
R/W-0  
T0IF  
R/W-0  
INTF  
R/W-x  
GPIF  
R
= Readable bit  
W = Writable bit  
bit7  
bit0  
U
= Unimplemented bit,  
read as ‘0’  
- n = Value at POR reset  
bit 7:  
bit 6:  
bit 5:  
bit 4:  
bit 3:  
bit 2:  
bit 1:  
bit 0:  
GIE: Global Interrupt Enable bit  
1= Enables all un-masked interrupts  
0= Disables all interrupts  
PEIE: Peripheral Interrupt Enable bit  
1= Enables all un-masked peripheral interrupts  
0= Disables all peripheral interrupts  
T0IE: TMR0 Overflow Interrupt Enable bit  
1= Enables the TMR0 interrupt  
0= Disables the TMR0 interrupt  
INTE: INT External Interrupt Enable bit  
1= Enables the external interrupt on GP2/INT/T0CKI/AN2 pin  
0= Disables the external interrupt on GP2/INT/T0CKI/AN2 pin  
GPIE: GPIO Interrupt on Change Enable bit  
1= Enables the GPIO Interrupt on Change  
0= Disables the GPIO Interrupt on Change  
T0IF: TMR0 Overflow Interrupt Flag bit  
1= TMR0 register has overflowed (must be cleared in software)  
0= TMR0 register did not overflow  
INTF: INT External Interrupt Flag bit  
1= The external interrupt on GP2/INT/T0CKI/AN2 pin occurred (must be cleared in software)  
0= The external interrupt on GP2/INT/T0CKI/AN2 pin did not occur  
GPIF: GPIO Interrupt on Change Flag bit  
1= GP0, GP1 or GP3 pins changed state (must be cleared in software)  
0= Neither GP0, GP1 nor GP3 pins have changed state  
1999 Microchip Technology Inc.  
DS30561B-page 17  
PIC12C67X  
4.2.2.4  
PIE1 REGISTER  
Note: Bit PEIE (INTCON<6>) must be set to  
This register contains the individual enable bits for the  
Peripheral interrupts.  
enable any peripheral interrupt.  
REGISTER 4-4:  
PIE1 REGISTER (ADDRESS 8Ch)  
U-0  
R/W-0  
ADIE  
U-0  
U-0  
U-0  
U-0  
U-0  
U-0  
R
= Readable bit  
W = Writable bit  
bit7  
bit0  
U
= Unimplemented bit,  
read as ‘0’  
- n = Value at POR reset  
bit 7:  
bit 6:  
Unimplemented: Read as ’0’  
ADIE: A/D Converter Interrupt Enable bit  
1= Enables the A/D interrupt  
0= Disables the A/D interrupt  
bit 5-0: Unimplemented: Read as ’0’  
DS30561B-page 18  
1999 Microchip Technology Inc.  
PIC12C67X  
4.2.2.5  
PIR1 REGISTER  
Note: Interrupt flag bits get set when an interrupt  
condition occurs, regardless of the state of  
its corresponding enable bit or the global  
enable bit, GIE (INTCON<7>). User soft-  
ware should ensure the appropriate inter-  
rupt flag bits are clear prior to enabling an  
interrupt.  
This register contains the individual flag bits for the  
Peripheral interrupts.  
REGISTER 4-5:  
PIR1 REGISTER (ADDRESS 0Ch)  
U-0  
R/W-0  
ADIF  
U-0  
U-0  
U-0  
U-0  
U-0  
U-0  
R
= Readable bit  
W = Writable bit  
bit7  
bit0  
U
= Unimplemented bit,  
read as ‘0’  
- n = Value at POR reset  
bit 7:  
bit 6:  
Unimplemented: Read as ’0’  
ADIF: A/D Converter Interrupt Flag bit  
1= An A/D conversion completed (must be cleared in software)  
0= The A/D conversion is not complete  
bit 5-0: Unimplemented: Read as ’0’  
1999 Microchip Technology Inc.  
DS30561B-page 19  
PIC12C67X  
4.2.2.6  
PCON REGISTER  
The Power Control (PCON) Register contains a flag bit  
to allow differentiation between a Power-on Reset  
(POR), an external MCLR Reset and a WDT Reset.  
REGISTER 4-6:  
PCON REGISTER (ADDRESS 8Eh)  
U-0  
U-0  
U-0  
U-0  
U-0  
U-0  
R/W-0  
U-0  
POR  
R
= Readable bit  
W = Writable bit  
bit7  
bit0  
U
= Unimplemented bit,  
read as ‘0’  
- n = Value at POR reset  
bit 7-2: Unimplemented: Read as ’0’  
bit 1:  
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:  
Unimplemented: Read as ’0’  
DS30561B-page 20  
1999 Microchip Technology Inc.  
PIC12C67X  
4.2.2.7  
OSCCAL REGISTER  
The Oscillator Calibration (OSCCAL) Register is used  
to calibrate the internal 4 MHz oscillator. It contains four  
bits for fine calibration and two other bits to either  
increase or decrease frequency.  
REGISTER 4-7:  
OSCCAL REGISTER (ADDRESS 8Fh)  
R/W-0  
CAL3  
R/W-1  
CAL2  
R/W-1  
CAL1  
R/W-1  
CAL0  
R/W-0  
R/W-0  
U-0  
U-0  
CALFST CALSLW  
R
= Readable bit  
W = Writable bit  
bit7  
bit0  
U
= Unimplemented bit,  
read as ‘0’  
- n = Value at POR reset  
bit 7-4: CAL<3:0>: Fine Calibration  
bit 3:  
CALFST: Calibration Fast  
1= Increase frequency  
0= No change  
bit 2:  
CALSLW: Calibration Slow  
1= Decrease frequency  
0= No change  
bit 1-0: Unimplemented: Read as ’0’  
Note: If CALFST = 1 and CALSLW = 1, CALFST has precedence.  
1999 Microchip Technology Inc.  
DS30561B-page 21  
PIC12C67X  
4.3.2  
STACK  
4.3  
PCL and PCLATH  
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 4-3 shows the  
two situations for the loading of the PC. The upper  
example in the figure shows how the PC is loaded on a  
write to PCL (PCLATH<4:0> PCH). The lower exam-  
ple in the figure shows how the PC is loaded during a  
CALLor GOTOinstruction (PCLATH<4:3> PCH).  
The PIC12C67X family has an 8-level deep x 13-bit  
wide hardware stack. 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 inter-  
rupt causes a branch. The stack is POPed in the event  
of a RETURN, RETLWor a RETFIEinstruction execu-  
tion. PCLATH is not affected by a PUSH or POP oper-  
ation.  
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 4-3: LOADING OF PC IN  
DIFFERENT SITUATIONS  
PCH  
PCL  
12  
8
7
0
Instruction with  
PCL as  
Destination  
Note 1: There are no status bits to indicate stack  
PC  
overflow or stack underflow conditions.  
8
PCLATH<4:0>  
PCLATH  
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 inter-  
rupt address.  
5
ALU result  
PCH  
12 11 10  
PCL  
8
7
0
GOTO, CALL  
PC  
4.4  
Program Memory Paging  
PCLATH<4:3>  
PCLATH  
11  
The PIC12C67X ignores both paging bits  
PCLATH<4:3>, which are used to access program  
memory when more than one page is available. The  
use of PCLATH<4:3> as general purpose read/write  
bits for the PIC12C67X is not recommended since this  
may affect upward compatibility with future products.  
2
Opcode <10:0>  
4.3.1  
COMPUTED GOTO  
A Computed GOTO is accomplished by adding an off-  
set to the program counter (ADDWF PCL). When doing  
a table read using a computed GOTO method, care  
should be exercised if the table location crosses a PCL  
memory boundary (each 256 byte block). Refer to the  
application note “Implementing a Table Read" (AN556).  
DS30561B-page 22  
1999 Microchip Technology Inc.  
PIC12C67X  
4.5  
Indirect Addressing, INDF and FSR  
Registers  
EXAMPLE 4-1: INDIRECT ADDRESSING  
movlw 0x20  
movwf FSR  
;initialize pointer  
;to RAM  
The INDF Register is not a physical register. Address-  
ing the INDF Register will cause indirect addressing.  
NEXT  
clrf  
incf  
INDF  
;clear INDF register  
FSR,F ;inc pointer  
Any instruction using the INDF register actually  
accesses the register pointed to by the File Select Reg-  
ister, FSR. Reading the INDF Register itself indirectly  
(FSR = ’0’) will read 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 Register and the IRP bit  
(STATUS<7>), as shown in Figure 4-4. However, IRP is  
not used in the PIC12C67X.  
btfss FSR,4 ;all done?  
goto  
NEXT  
;no clear next  
;yes continue  
CONTINUE  
:
A simple program to clear RAM locations 20h-2Fh  
using indirect addressing is shown in Example 4-1.  
FIGURE 4-4: DIRECT/INDIRECT ADDRESSING  
Direct Addressing  
Indirect Addressing  
(1)  
(1)  
from opcode  
7
RP1 RP0  
6
0
0
IRP  
FSR register  
bank select  
180h  
location select  
bank select  
location select  
00  
01  
10  
11  
00h  
not used  
Data  
Memory  
7Fh  
1FFh  
Bank 0  
Bank 1 Bank 2  
Bank 3  
For register file map detail see Figure 4-2.  
Note 1: The RP1 and IRP bits are reserved; always maintain these bits clear.  
1999 Microchip Technology Inc.  
DS30561B-page 23  
PIC12C67X  
NOTES:  
DS30561B-page 24  
1999 Microchip Technology Inc.  
PIC12C67X  
5.3  
I/O Interfacing  
5.0  
I/O PORT  
The equivalent circuit for an I/O port pin is shown in  
Figure 5-1 through Figure 5-5. All port pins, except  
GP3, which is input only, may be used for both input  
and output operations. For input operations, these  
ports are non-latching. Any input must be present until  
read by an input instruction (i.e., MOVF GPIO,W). The  
outputs are latched and remain unchanged until the  
output latch is rewritten. To use a port pin as output,  
the corresponding direction control bit in TRIS must be  
cleared (= 0). For use as an input, the corresponding  
TRIS bit must be set. Any I/O pin (except GP3) can be  
programmed individually as input or output.  
As with any other register, the I/O register can be  
written and read under program control. However, read  
instructions (i.e., MOVF GPIO,W) always read the I/O  
pins independent of the pin’s input/output modes. On  
RESET, all I/O ports are defined as input (inputs are at  
hi-impedance), since the I/O control registers are all  
set.  
5.1  
GPIO  
GPIO is an 8-bit I/O register. Only the low order 6 bits  
are used (GP<5:0>). Bits 6 and 7 (SDA and SCL,  
respectively) are used by the EEPROM peripheral on  
the PIC12CE673/674. Refer to Section 6.0 and  
Appendix B for use of SDA and SCL. Please note that  
GP3 is an input only pin. The configuration word can  
set several I/O’s to alternate functions. When acting as  
alternate functions, the pins will read as ‘0’ during port  
read. Pins GP0, GP1 and GP3 can be configured with  
weak pull-ups and also with interrupt-on-change. The  
interrupt on change and weak pull-up functions are not  
pin selectable. If pin 4, (GP3), is configured as MCLR,  
a weak pull-up is always on. Interrupt-on-change for  
this pin is not set and GP3 will read as '0'. Interrupt-on-  
change is enabled by setting bit GPIE, INTCON<3>.  
Note that external oscillator use overrides the GPIO  
functions on GP4 and GP5.  
Port pins GP6 (SDA) and GP7 (SCL) are used for the  
serial EEPROM interface on the PIC12CE673/674.  
These port pins are not available externally on the  
package. Users should avoid writing to pins GP6  
(SDA) and GP7 (SCL) when not communicating with  
the serial EEPROM memory. Please see Section 6.0,  
EEPROM Peripheral Operation, for information on  
serial EEPROM communication.  
Note:  
On a Power-on Reset, GP0, GP1, GP2  
and GP4 are configured as analog inputs  
and read as '0'.  
5.2  
TRIS Register  
This register controls the data direction for GPIO. A '1'  
from a TRIS Register bit puts the corresponding output  
driver in a hi-impedance mode. A '0' puts the contents  
of the output data latch on the selected pins, enabling  
the output buffer. The exceptions are GP3, which is  
input only and its TRIS bit will always read as '1', while  
GP6 and GP7 TRIS bits will read as ’0’.  
Note:  
A read of the ports reads the pins, not the  
output data latches. That is, if an output  
driver on a pin is enabled and driven high,  
but the external system is holding it low, a  
read of the port will indicate that the pin is  
low.  
Upon reset, the TRIS Register is all '1's, making all  
pins inputs.  
TRIS for pins GP4 and GP5 is forced to a ’1’ where  
appropriate. Writes to TRIS <5:4> will have an effect  
in EXTRC and INTRC oscillator modes only. When  
GP4 is configured as CLKOUT, changes to TRIS<4>  
will have no effect.  
1999 Microchip Technology Inc.  
DS30561B-page 25  
PIC12C67X  
FIGURE 5-1: BLOCK DIAGRAM OF GP0/AN0 AND GP1/AN1/VREF PIN  
GPPU  
Data Bus  
D
Q
Q
VDD  
P
VDD  
P
VDD  
WR PORT  
CK  
I/O Pin  
Data Latch  
N
D
Q
Q
VSS  
VSS  
WR TRIS  
CK  
TRIS Latch  
Analog  
Input  
TTL  
Input  
Buffer  
Mode  
RD TRIS  
Q
D
EN  
RD PORT  
(1)  
(1)  
GP0/INT and GP1/INT  
To A/D Converter  
Note 1: Wake-up on pin change interrupts for GP0 and GP1.  
DS30561B-page 26  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 5-2: BLOCK DIAGRAM OF GP2/T0CKI/AN2/INT PIN  
Data Bus  
D
Q
Q
VDD  
P
VDD  
WR PORT  
CK  
I/O Pin  
Data Latch  
N
D
Q
Q
VSS  
VSS  
WR TRIS  
CK  
TRIS Latch  
Analog  
Input  
Mode  
Schmitt Trigger  
Input Buffer  
RD TRIS  
Q
D
EN  
RD PORT  
TMR0 Clock Input  
GP2/INT  
To A/D Converter  
1999 Microchip Technology Inc.  
DS30561B-page 27  
PIC12C67X  
FIGURE 5-3: BLOCK DIAGRAM OF GP3/MCLR/VPP PIN  
VDD  
GPPU  
P
MCLREN  
Input Pin  
VSS  
MCLR  
Schmitt Trigger  
Input Buffer  
Program Mode  
HV Detect  
TTL Input  
Buffer  
Data Bus  
Q
D
EN  
RD PORT  
RD TRIS  
GP3/INT  
VSS  
(1)  
Note 1: Wake-up on pin change interrupt for GP3.  
DS30561B-page 28  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 5-4: BLOCK DIAGRAM OF GP4/OSC2/AN3/CLKOUT PIN  
INTRC or EXTRC w/ CLKOUT  
CLKOUT (FOSC/4)  
1
0
From OSC1 Oscillator  
Data Bus  
Circuit  
D
Q
VDD  
VDD  
WR PORT  
CK  
Q
P
I/O Pin  
Data Latch  
N
VSS  
VSS  
INTRC/  
EXTRC  
D
Q
Q
INTRC or EXTRC  
w/o CLKOUT  
WR TRIS  
CK  
TRIS Latch  
Analog  
Input  
Mode  
TTL  
Input Buffer  
RD TRIS  
Q
D
EN  
RD PORT  
To A/D Converter  
1999 Microchip Technology Inc.  
DS30561B-page 29  
PIC12C67X  
FIGURE 5-5: BLOCK DIAGRAM OF GP5/OSC1/CLKIN PIN  
To OSC2  
Oscillator  
Circuit  
Data Bus  
D
Q
Q
VDD  
VDD  
WR PORT  
EN  
P
Data Latch  
I/O Pin  
N
D
Q
Q
WR TRIS  
VSS  
VSS  
INTRC  
EN  
TRIS Latch  
INTRC  
TTL  
Input Buffer  
RD TRIS  
Q
D
EN  
RD PORT  
DS30561B-page 30  
1999 Microchip Technology Inc.  
PIC12C67X  
TABLE 5-1:  
SUMMARY OF PORT REGISTERS  
Value on  
Power-on  
Reset  
Value on  
all other  
Resets  
Address  
Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2 Bit 1 Bit 0  
85h  
81h  
03h  
05h  
TRIS  
GPIO Data Direction Register  
--11 1111  
1111 1111  
0001 1xxx  
11xx xxxx  
--11 1111  
1111 1111  
000q quuu  
11uu uuuu  
OPTION  
STATUS  
GPIO  
GPPU  
IRP(1)  
INTEDG  
RP1(1)  
T0CS  
RP0  
T0SE  
TO  
PSA  
PD  
PS2  
Z
PS1  
DC  
PS0  
C
(2)  
(2)  
GP5  
GP4  
GP3  
GP2  
GP1 GP0  
SCL  
SDA  
Legend: Shaded cells not used by Port Registers, read as ‘0’, — = unimplemented, read as '0', x= unknown, u= unchanged,  
q = see tables in Section 9.4 for possible values.  
Note 1: The IRP and RP1 bits are reserved on the PIC12C67X; always maintain these bits clear.  
2: The SCL and SDA bits are unimplemented on the PIC12C671 and PIC12C672.  
Example 5-1 shows the effect of two sequential read-  
modify-write instructions on an I/O port.  
5.4  
I/O Programming Considerations  
5.4.1  
BI-DIRECTIONAL I/O PORTS  
EXAMPLE 5-1: READ-MODIFY-WRITE  
INSTRUCTIONS ON AN  
I/O PORT  
Any instruction which writes, operates internally as a  
read followed by a write operation. The BCFand BSF  
instructions, for example, read the register into the  
CPU, execute the bit operation and write the result back  
to the register. Caution must be used when these  
instructions are applied to a port with both inputs and  
outputs defined. For example, a BSFoperation on bit5  
of GPIO will cause all eight bits of GPIO to be read into  
the CPU. Then the BSF operation takes place on bit5  
and GPIO is written to the output latches. If another bit  
of GPIO is used as a bi-directional I/O pin (i.e., bit0) and  
it is defined as an input at this time, the input signal  
present on the pin itself would be read into the CPU and  
rewritten to the data latch of this particular pin, overwrit-  
ing the previous content. As long as the pin stays in the  
input mode, no problem occurs. However, if bit0 is  
switched to an output, the content of the data latch may  
now be unknown.  
;Initial GPIO Settings  
; GPIO<5:3> Inputs  
; GPIO<2:0> Outputs  
;
;
;
GPIO latch GPIO pins  
---------- ----------  
BCF  
BCF  
MOVLW 007h  
TRIS GPIO  
GPIO, 5  
GPIO, 4  
;--01 -ppp  
;--10 -ppp  
;
--11 pppp  
--11 pppp  
;--10 -ppp  
--10 pppp  
;
;Note that the user may have expected the pin  
;values to be --00 pppp. The 2nd BCF caused  
;GP5 to be latched as the pin value (High).  
A pin actively outputting a Low or High should not be  
driven from external devices at the same time in order  
to change the level on this pin (“wired-or”, “wired-and”).  
The resulting high output currents may damage the  
chip.  
Reading the port register reads the values of the port  
pins. Writing to the port register writes the value to the  
port latch. When using read-modify-write instructions  
(i.e., BCF, BSF, etc.) on a port, the value of the port  
pins is read, the desired operation is done to this value,  
and this value is then written to the port latch.  
1999 Microchip Technology Inc.  
DS30561B-page 31  
PIC12C67X  
NOTES:  
DS30561B-page 32  
1999 Microchip Technology Inc.  
PIC12C67X  
6.1  
Bus Characteristics  
6.0  
EEPROM PERIPHERAL  
OPERATION  
The following bus protocol is to be used with the  
EEPROM data memory. In this section, the term “proces-  
sor” is used to denote the portion of the PIC12C67X that  
interfaces to the EEPROM via software.  
The PIC12CE673 and PIC12CE674 each have 16  
bytes of EEPROM data memory. The EEPROM mem-  
ory has an endurance of 1,000,000 erase/write cycles  
and a data retention of greater than 40 years. The  
EEPROM data memory supports a bi-directional 2-wire  
bus and data transmission protocol. These two-wires  
are serial data (SDA) and serial clock (SCL), that are  
mapped to bit6 and bit7, respectively, of the GPIO reg-  
ister (SFR 06h). Unlike the GP0-GP5 that are con-  
nected to the I/O pins, SDA and SCL are only  
connected to the internal EEPROM peripheral. For  
most applications, all that is required is calls to the  
following functions:  
• Data transfer may be initiated only when the bus  
is not busy.  
During data transfer, the data line must remain stable  
whenever the clock line is HIGH. Changes in the data  
line while the clock line is HIGH will be interpreted as a  
START or STOP condition.  
Accordingly, the following bus conditions have been  
defined (Figure 6-3).  
6.1.1  
BUS NOT BUSY (A)  
; Byte_Write: Byte write routine  
Both data and clock lines remain HIGH.  
;
;
;
Inputs:EEPROM Address  
EEPROM Data  
EEADDR  
EEDATA  
6.1.2  
START DATA TRANSFER (B)  
Outputs:  
Return 01 in W if OK, else  
return 00 in W  
A HIGH to LOW transition of the SDA line while the  
clock (SCL) is HIGH determines a START condition. All  
commands must be preceded by a START condition.  
;
; Read_Current: Read EEPROM at address  
currently held by EE device.  
;
;
;
Inputs:NONE  
Outputs:  
6.1.3  
STOP DATA TRANSFER (C)  
EEPROM Data  
EEDATA  
Return 01 in W if OK, else  
return 00 in W  
A LOW to HIGH transition of the SDA line while the  
clock (SCL) is HIGH determines a STOP condition. All  
operations must be ended with a STOP condition.  
;
; Read_Random: Read EEPROM byte at supplied  
address  
;
;
;
6.1.4  
DATA VALID (D)  
Inputs:EEPROM Address  
Outputs: EEPROM Data  
EEADDR  
EEDATA  
The state of the data line represents valid data when,  
after a START condition, the data line is stable for the  
duration of the HIGH period of the clock signal.  
Return 01 in W if OK,  
else return 00 in W  
The code for these functions is available on our web  
site (www.microchip.com). The code will be accessed  
by either including the source code FL67XINC.ASM or  
by linking FLASH67X.ASM. FLASH67X.INC provides  
external definition to the calling program.  
The data on the line must be changed during the LOW  
period of the clock signal. There is one bit of data per  
clock pulse.  
Each data transfer is initiated with a START condition  
and terminated with a STOP condition. The number of  
the data bytes transferred between the START and  
STOP conditions is determined by the available data  
EEPROM space.  
6.0.1  
SERIAL DATA  
SDA is a bi-directional pin used to transfer addresses  
and data into and data out of the device.  
For normal data transfer, SDA is allowed to change only  
during SCL low. Changes during SCL high are  
reserved for indicating the START and STOP condi-  
tions.  
6.0.2  
SERIAL CLOCK  
This SCL signal is used to synchronize the data trans-  
fer from and to the EEPROM.  
1999 Microchip Technology Inc.  
DS30561B-page 33  
PIC12C67X  
6.1.5  
ACKNOWLEDGE  
The device that acknowledges has to pull down the  
SDA line during the acknowledge clock pulse in such a  
way that the SDA line is stable LOW during the HIGH  
period of the acknowledge related clock pulse. Of  
course, setup and hold times must be taken into  
account. The processor must signal an end of data to  
the EEPROM by not generating an acknowledge bit on  
the last byte that has been clocked out of the EEPROM.  
In this case, the EEPROM must leave the data line  
HIGH to enable the processor to generate the STOP  
condition (Figure 6-4).  
The EEPROM, when addressed, will generate an  
acknowledge after the reception of each byte. The pro-  
cessor must generate an extra clock pulse which is  
associated with this acknowledge bit.  
Note: Acknowledge bits are not generated if an  
internal programming cycle is in progress.  
FIGURE 6-1: BLOCK DIAGRAM OF GPIO6 (SDA LINE)  
VDD  
Reset  
To EEPROM SDA  
Pad  
D
P
Write  
GPIO  
CK  
Q
Data Bus  
Output Latch  
Q
D
Schmitt Trigger  
CK  
Input Latch  
ltchpin  
Read  
GPIO  
FIGURE 6-2: BLOCK DIAGRAM OF GPIO7 (SCL LINE)  
VDD  
To EEPROM SCL  
Pad  
D
P
N
Write  
GPIO  
CK  
Q
Data Bus  
Output Latch  
Q
D
Schmitt Trigger  
CK  
ltchpin  
Read  
GPIO  
DS30561B-page 34  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 6-3: DATA TRANSFER SEQUENCE ON THE SERIAL BUS  
(A)  
(B)  
(C)  
(D)  
(C)  
(A)  
SCL  
SDA  
START  
CONDITION  
STOP  
CONDITION  
ADDRESS OR  
ACKNOWLEDGE  
VALID  
DATA  
ALLOWED  
TO CHANGE  
FIGURE 6-4: ACKNOWLEDGE TIMING  
Acknowledge  
Bit  
1
2
3
4
5
6
7
8
9
1
2
3
SCL  
SDA  
Data from transmitter  
Data from transmitter  
Receiver must release the SDA line at this  
point so the Transmitter can continue  
sending data.  
Transmitter must release the SDA line at this point  
allowing the Receiver to pull the SDA line low to  
acknowledge the previous eight bits of data.  
6.2  
Device Addressing  
FIGURE 6-5: CONTROL BYTE FORMAT  
After generating a START condition, the processor  
transmits a control byte consisting of a EEPROM  
address and a Read/Write bit that indicates what type  
of operation is to be performed. The EEPROM address  
consists of a 4-bit device code (1010) followed by three  
don’t care bits.  
Read/Write Bit  
Device Select  
Bits  
Don’t Care  
Bits  
S
1
0
1
0
X
X
X
R/W ACK  
The last bit of the control byte determines the operation  
to be performed. When set to a one, a read operation  
is selected, and when set to a zero, a write operation is  
selected (Figure 6-5). The bus is monitored for its cor-  
responding EEPROM address all the time. It generates  
an acknowledge bit if the EEPROM address was true  
and it is not in a programming mode.  
EEPROM Address  
Start Condition  
Acknowledge Condition  
1999 Microchip Technology Inc.  
DS30561B-page 35  
PIC12C67X  
6.3  
Write Operations  
6.4  
Acknowledge Polling  
Since the EEPROM will not acknowledge during a write  
cycle, this can be used to determine when the cycle is  
complete (this feature can be used to maximize bus  
throughput). Once the stop condition for a write com-  
mand has been issued from the processor, the device  
initiates the internally timed write cycle. ACK polling  
can be initiated immediately. This involves the proces-  
sor sending a start condition followed by the control  
byte for a write command (R/W = 0). If the device is still  
busy with the write cycle, then no ACK will be returned.  
If no ACK is returned, then the start bit and control byte  
must be re-sent. If the cycle is complete, then the  
device will return the ACK and the processor can then  
proceed with the next read or write command. (See  
Figure 6-6 for flow diagram.)  
6.3.1  
BYTE WRITE  
Following the start signal from the processor, the  
device code (4 bits), the don’t care bits (3 bits), and the  
R/W bit (which is a logic low) are placed onto the bus  
by the processor. This indicates to the addressed  
EEPROM that a byte with a word address will follow  
after it has generated an acknowledge bit during the  
ninth clock cycle. Therefore, the next byte transmitted  
by the processor is the word address and will be written  
into the address pointer. Only the lower four address  
bits are used by the device, and the upper four bits are  
don’t cares. If the address byte is acknowledged, the  
processor will then transmit the data word to be written  
into the addressed memory location. The memory  
acknowledges again and the processor generates a  
stop condition. This initiates the internal write cycle,  
and during this time will not generate acknowledge sig-  
nals. After a byte write command, the internal address  
counter will not be incremented and will point to the  
same address location that was just written. If a stop bit  
sequence is transmitted to the device at any point in the  
write command sequence before the entire sequence  
is complete, then the command will abort and no data  
will be written. If more than 8 data bits are transmitted  
before the stop bit sequence is sent, then the device will  
clear the previously loaded byte and begin loading the  
data buffer again. If more than one data byte is trans-  
mitted to the device and a stop bit is sent before a full  
eight data bits have been transmitted, then the write  
command will abort and no data will be written. The  
EEPROM memory employs a VCC threshold detector  
circuit, which disables the internal erase/write logic if  
the VCC is below minimum VDD. Byte write operations  
must be preceded and immediately followed by a bus  
not busy bus cycle where both SDA and SCL are held  
high. (See Figure 6-7 for Byte Write operation.)  
FIGURE 6-6: ACKNOWLEDGE POLLING  
FLOW  
Send  
Write Command  
Send Stop  
Condition to  
Initiate Write Cycle  
Send Start  
Send Control Byte  
with R/W = 0  
Did EEPROM  
NO  
Acknowledge  
(ACK = 0)?  
YES  
Next  
Operation  
FIGURE 6-7: BYTE WRITE  
S
T
A
R
S
T
O
P
CONTROL  
BYTE  
WORD  
ADDRESS  
DATA  
T
SDA LINE  
ACTIVITY  
P
S
1
0
1
0
X
X
X
0
X
X
X
X
A
C
K
A
C
K
A
C
K
X = Don’t Care Bit  
DS30561B-page 36  
1999 Microchip Technology Inc.  
PIC12C67X  
address is sent, the processor generates a start condi-  
tion following the acknowledge. This terminates the  
write operation, but not before the internal address  
pointer is set. Then the processor issues the control  
byte again, but with the R/W bit set to a one. The  
EEPROM will then issue an acknowledge and trans-  
mits the 8-bit data word. The processor will not  
acknowledge the transfer, but does generate a stop  
condition and the EEPROM discontinues transmission  
(Figure 6-9). After this command, the internal address  
counter will point to the address location following the  
one that was just read.  
6.5  
Read Operations  
Read operations are initiated in the same way as write  
operations with the exception that the R/W bit of the  
EEPROM address is set to one. There are three basic  
types of read operations; current address read, random  
read and sequential read.  
6.5.1  
CURRENT ADDRESS READ  
The EEPROM contains an address counter that main-  
tains the address of the last word accessed, internally  
incremented by one. Therefore, if the previous read  
access was to address n, the next current address read  
operation would access data from address n + 1. Upon  
receipt of the EEPROM address with the R/W bit set to  
one, the EEPROM issues an acknowledge and trans-  
mits the 8-bit data word. The processor will not  
acknowledge the transfer, but does generate a stop  
condition and the EEPROM discontinues transmission  
(Figure 6-8).  
6.5.3  
SEQUENTIAL READ  
Sequential reads are initiated in the same way as a ran-  
dom read, except that after the device transmits the first  
data byte, the processor issues an acknowledge as  
opposed to a stop condition in a random read. This  
directs the EEPROM to transmit the next sequentially  
addressed 8-bit word (Figure 6-10).  
6.5.2  
RANDOM READ  
To provide sequential reads, the EEPROM contains an  
internal address pointer, which is incremented by one  
at the completion of each read operation. This address  
pointer allows the entire memory contents to be serially  
read during one operation.  
Random read operations allow the processor to access  
any memory location in a random manner. To perform  
this type of read operation, first the word address must  
be set. This is done by sending the word address to the  
EEPROM as part of a write operation. After the word  
FIGURE 6-8: CURRENT ADDRESS READ  
S
T
A
R
S
T
O
P
CONTROL  
BYTE  
T
SDA LINE  
ACTIVITY  
S 1 0 1 0 X X X 1  
P
A
C
K
N
O
DATA  
A
C
K
X = Don’t Care Bit  
FIGURE 6-9: RANDOM READ  
S
T
A
R
T
S
T
A
R
T
S
T
O
P
CONTROL  
BYTE  
WORD  
ADDRESS (n)  
CONTROL  
BYTE  
X X X X  
P
S 1 0 1 0 X X X 0  
S 1 0 1 0 X X X 1  
SDA LINE  
ACTIVITY  
A
C
K
A
C
K
A
C
K
N
O
DATA (n)  
A
C
K
X = Don’t Care Bit  
FIGURE 6-10: SEQUENTIAL READ  
S
T
O
P
CONTROL  
DATA n  
BYTE  
DATA n + 1  
DATA n + 2  
DATA n + X  
SDA LINE  
ACTIVITY  
P
A
C
K
A
C
K
A
C
K
A
C
K
N
O
A
C
K
1999 Microchip Technology Inc.  
DS30561B-page 37  
PIC12C67X  
NOTES:  
DS30561B-page 38  
1999 Microchip Technology Inc.  
PIC12C67X  
(OPTION<4>). Clearing bit T0SE selects the rising  
edge. Restrictions on the external clock input are dis-  
cussed in detail in Section 7.2.  
7.0  
TIMER0 MODULE  
The Timer0 module timer/counter has the following fea-  
tures:  
The prescaler is mutually exclusively shared between  
the Timer0 module and the Watchdog Timer. The pres-  
caler assignment is controlled in software by control bit  
PSA (OPTION<3>). Clearing bit PSA will assign the  
prescaler to the Timer0 module. The prescaler is not  
readable or writable. When the prescaler is assigned to  
the Timer0 module, prescale values of 1:2, 1:4, ...,  
1:256 are selectable. Section 7.3 details the operation  
of the prescaler.  
• 8-bit timer/counter  
• Readable and writable  
• 8-bit software programmable prescaler  
• Internal or external clock select  
• Interrupt on overflow from FFh to 00h  
• Edge select for external clock  
Figure 7-1 is a simplified block diagram of the Timer0  
module.  
7.1  
Timer0 Interrupt  
Timer mode is selected by clearing bit T0CS  
(OPTION<5>). In timer mode, the Timer0 module will  
increment every instruction cycle (without prescaler). If  
the TMR0 register is written, the increment is inhibited  
for the following two instruction cycles (Figure 7-2 and  
Figure 7-3). The user can work around this by writing  
an adjusted value to the TMR0 register.  
The TMR0 interrupt is generated when the TMR0 reg-  
ister overflows from FFh to 00h. This overflow sets bit  
T0IF (INTCON<2>). The interrupt can be masked by  
clearing bit T0IE (INTCON<5>). Bit T0IF must be  
cleared in software by the Timer0 module interrupt ser-  
vice routine before re-enabling this interrupt. The  
TMR0 interrupt cannot awaken the processor from  
SLEEP, since the timer is shut off during SLEEP. See  
Figure 7-4 for Timer0 interrupt timing.  
Counter mode is selected by setting bit T0CS  
(OPTION<5>). In counter mode, Timer0 will increment  
either on every rising or falling edge of pin RA4/T0CKI.  
The incrementing edge is determined by the bit T0SE  
FIGURE 7-1: TIMER0 BLOCK DIAGRAM  
Data Bus  
FOSC/4  
0
1
8
1
0
Sync with  
Internal  
clocks  
TMR0  
Programmable  
Prescaler  
GP2/TOCKI/  
AN2/INT  
(2 TCY delay)  
TOSE  
3
Set interrupt  
flag bit T0IF  
on overflow  
PS<2:0>  
PSA  
TOCS  
Note 1: TOCS, TOSE, PSA, PS<2:0> (OPTION<5:0>).  
2: The prescaler is shared with Watchdog Timer (refer to Figure 7-6 for detailed block diagram).  
FIGURE 7-2: TIMER0 TIMING: INTERNAL CLOCK/NO PRESCALE  
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4  
PC  
(Program  
Counter)  
PC-1  
PC  
PC+1  
PC+2  
PC+3  
PC+4  
PC+5  
PC+6  
Instruction  
Fetch  
MOVF TMR0,WMOVF TMR0,WMOVF TMR0,WMOVF TMR0,WMOVF TMR0,W  
MOVWF TMR0  
T0  
T0+1  
T0+2  
NT0  
NT0  
NT0  
NT0+1  
NT0+2  
TMR0  
Instruction  
Executed  
Read TMR0  
reads NT0 + 1  
Read TMR0 Read TMR0 Read TMR0  
reads NT0 reads NT0 reads NT0  
Read TMR0  
reads NT0 + 2  
Write TMR0  
executed  
1999 Microchip Technology Inc.  
DS30561B-page 39  
PIC12C67X  
FIGURE 7-3: TIMER0 TIMING: INTERNAL CLOCK/PRESCALE 1:2  
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4  
PC  
(Program  
Counter)  
PC-1  
PC  
PC+1  
PC+2  
PC+3  
PC+4  
PC+5  
PC+6  
MOVF TMR0,WMOVF TMR0,WMOVF TMR0,WMOVF TMR0,WMOVF TMR0,W  
MOVWF TMR0  
Instruction  
Fetch  
T0  
T0+1  
NT0+1  
NT0  
TMR0  
Instruction  
Execute  
Read TMR0  
reads NT0  
Read TMR0 Read TMR0 Read TMR0  
reads NT0 reads NT0 reads NT0  
Read TMR0  
reads NT0 + 1  
Write TMR0  
executed  
FIGURE 7-4: TIMER0 INTERRUPT TIMING  
Q1 Q2 Q3  
Q4  
Q1 Q2 Q3  
Q4  
Q1 Q2 Q3  
Q4  
Q1 Q2 Q3  
Q4  
Q1 Q2 Q3  
Q4  
OSC1  
CLKOUT(3)  
Timer0  
FEh  
FFh  
00h  
01h  
02h  
1
1
T0IF bit  
(INTCON<2>)  
Interrupt Latency(2)  
GIE bit  
(INTCON<7>)  
INSTRUCTION  
FLOW  
PC  
PC  
PC +1  
PC +1  
0004h  
0005h  
Instruction  
fetched  
Inst (PC)  
Inst (PC+1)  
Inst (0004h)  
Inst (0005h)  
Inst (0004h)  
Instruction  
executed  
Inst (PC-1)  
Dummy cycle  
Dummy cycle  
Inst (PC)  
Note 1: Interrupt flag bit T0IF is sampled here (every Q1).  
2: Interrupt latency = 3TCY where TCY = instruction cycle time.  
3: CLKOUT is available only in the INTRC and EXTRC oscillator modes.  
DS30561B-page 40  
1999 Microchip Technology Inc.  
PIC12C67X  
caler, so that the prescaler output is symmetrical. For  
the external clock to meet the sampling requirement,  
the ripple-counter must be taken into account. There-  
fore, it is necessary for T0CKI to have a period of at  
least 4TOSC (and a small RC delay of 40 ns) divided by  
the prescaler value. The only requirement on T0CKI  
high and low time is that they do not violate the mini-  
mum pulse width requirement of 10 ns. Refer to param-  
eters 40, 41 and 42 in the electrical specification of the  
desired device.  
7.2  
Using Timer0 with an External Clock  
When an external clock input is used for Timer0, it must  
meet certain requirements. The requirements ensure  
the external clock can be synchronized with the internal  
phase clock (TOSC). Also, there is a delay in the actual  
incrementing of Timer0 after synchronization.  
7.2.1  
EXTERNAL CLOCK SYNCHRONIZATION  
When no prescaler is used, the external clock input is  
used as the clock source. The synchronization of  
T0CKI with the internal phase clocks is accomplished  
by sampling the prescaler output on the Q2 and Q4  
cycles of the internal phase clocks (Figure 7-5). There-  
fore, it is necessary for T0CKI to be high for at least  
2TOSC (and a small RC delay of 20 ns) and low for at  
least 2TOSC (and a small RC delay of 20 ns). Refer to  
the electrical specification of the desired device.  
7.2.2  
TMR0 INCREMENT DELAY  
Since the prescaler output is synchronized with the  
internal clocks, there is a small delay from the time the  
external clock edge occurs to the time the Timer0 mod-  
ule is actually incremented. Figure 7-5 shows the delay  
from the external clock edge to the timer incrementing.  
When a prescaler is used, the external clock input is  
divided by the asynchronous ripple-counter type pres-  
FIGURE 7-5: TIMER0 TIMING WITH EXTERNAL CLOCK  
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4  
Small pulse  
misses sampling  
External Clock Input or  
Prescaler output(2)  
(1)  
(3)  
External Clock/Prescaler  
Output after sampling  
Increment Timer0 (Q4)  
Timer0  
T0  
T0 + 1  
T0 + 2  
Note 1: Delay from clock input change to Timer0 increment is 3TOSC to 7TOSC. (Duration of Q = TOSC). Therefore, the error  
in measuring the interval between two edges on Timer0 input = ±4TOSC max.  
2: External clock if no prescaler selected; prescaler output otherwise.  
3: The arrows indicate the points in time where sampling occurs.  
1999 Microchip Technology Inc.  
DS30561B-page 41  
PIC12C67X  
The PSA and PS<2:0> bits (OPTION<3:0>) determine  
the prescaler assignment and prescale ratio.  
7.3  
Prescaler  
An 8-bit counter is available as a prescaler for the  
Timer0 module, or as a postscaler for the Watchdog  
Timer, respectively (Figure 7-6). For simplicity, this  
counter is being referred to as “prescaler” throughout  
this data sheet. Note that there is only one prescaler  
available which is mutually exclusively shared between  
the Timer0 module and the Watchdog Timer. Thus, a  
prescaler assignment for the Timer0 module means  
that there is no prescaler for the Watchdog Timer, and  
vice-versa.  
When assigned to the Timer0 module, all instructions  
writing to the TMR0 register (i.e., CLRF 1, MOVWF 1,  
BSF 1,x...., etc.) will clear the prescaler. When  
assigned to WDT, a CLRWDT instruction will clear the  
prescaler along with the Watchdog Timer. The pres-  
caler is not readable or writable.  
FIGURE 7-6: BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER  
Data Bus  
8
CLKOUT (= FOSC/4)  
M
U
X
1
0
0
1
M
U
X
GP2/T0CKI/  
AN2/INT  
SYNC  
2
Cycles  
TMR0 reg  
T0SE  
T0CS  
Set flag bit T0IF  
on Overflow  
PSA  
0
1
8-bit Prescaler  
M
U
X
Watchdog  
Timer  
8
8 - to - 1MUX  
PS<2:0>  
PSA  
1
0
WDT Enable bit  
M U X  
PSA  
WDT  
Time-out  
Note: T0CS, T0SE, PSA, PS<2:0> are (OPTION<5:0>).  
DS30561B-page 42  
1999 Microchip Technology Inc.  
PIC12C67X  
7.3.1  
SWITCHING PRESCALER ASSIGNMENT  
To change prescaler from the WDT to the Timer0 mod-  
ule, use the sequence shown in Example 7-2.  
The prescaler assignment is fully under software con-  
trol, (i.e., it can be changed “on-the-fly” during program  
execution).  
EXAMPLE 7-2: CHANGING PRESCALER  
(WDTTIMER0)  
Note: To avoid an unintended device RESET, the  
following instruction sequence (shown in  
Example 7-1) must be executed when  
changing the prescaler assignment from  
Timer0 to the WDT. This sequence must  
be followed even if the WDT is disabled.  
CLRWDT  
;Clear WDT and  
;prescaler  
STATUS, RP0 ;Bank 1  
b’xxxx0xxx’ ;Select TMR0, new  
;prescale value and  
OPTION_REG ;clock source  
STATUS, RP0 ;Bank 0  
BSF  
MOVLW  
MOVWF  
BCF  
EXAMPLE 7-1: CHANGING PRESCALER  
(TIMER0WDT)  
BCF  
STATUS, RP0 ;Bank 0  
CLRF  
BSF  
TMR0  
;Clear TMR0 & Prescaler  
STATUS, RP0 ;Bank 1  
CLRWDT  
;Clears WDT  
MOVLW b’xxxx1xxx’ ;Select new prescale  
MOVWF OPTION_REG ;value & WDT  
STATUS, RP0 ;Bank 0  
BCF  
TABLE 7-1:  
REGISTERS ASSOCIATED WITH TIMER0  
Value on  
Value on  
POR  
Address Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
all other  
Resets  
01h  
TMR0  
Timer0 module’s register  
xxxx xxxx uuuu uuuu  
0000 000x 0000 000u  
1111 1111 1111 1111  
0Bh/8Bh INTCON  
GIE  
OPTION GPPU INTEDG  
TRIS  
PEIE  
T0IE  
T0CS  
TRIS5  
INTE  
T0SE  
TRIS4  
GPIE  
PSA  
T0IF  
PS2  
INTF  
PS1  
GPIF  
PS0  
81h  
85h  
TRIS3  
TRIS2  
TRIS1  
TRIS0 --11 1111 --11 1111  
Legend: x= unknown, u= unchanged, -= unimplemented locations read as '0'. Shaded cells are not used by Timer0.  
1999 Microchip Technology Inc.  
DS30561B-page 43  
PIC12C67X  
NOTES:  
DS30561B-page 44  
1999 Microchip Technology Inc.  
PIC12C67X  
The ADCON0 Register, shown in Figure 8-1, controls  
the operation of the A/D module. The ADCON1 Regis-  
ter, shown in Figure 8-2, configures the functions of the  
port pins. The port pins can be configured as analog  
inputs (GP1 can also be a voltage reference) or as dig-  
ital I/O.  
8.0  
ANALOG-TO-DIGITAL  
CONVERTER (A/D) MODULE  
The Analog-To-Digital (A/D) converter module has four  
analog inputs.  
The A/D allows conversion of an analog input signal to  
a corresponding 8-bit digital number (refer to Applica-  
tion Note AN546 for use of A/D Converter). The output  
of the sample and hold is the input into the converter,  
which generates the result via successive approxima-  
tion. The analog reference voltage is software select-  
able to either the device’s positive supply voltage (VDD)  
or the voltage level on the GP1/AN1/VREF pin. The A/D  
converter has a unique feature of being able to operate  
while the device is in SLEEP mode.  
Note 1: If the port pins are configured as analog  
inputs (reset condition), reading the port  
(MOVF GPIO,W) results in reading '0's.  
2: Changing ADCON1 Register can cause  
the GPIF and INTF flags to be set in the  
INTCON Register.  
These interrupts  
should be disabled prior to modifying  
ADCON1.  
The A/D module has three registers. These registers  
are:  
• A/D Result Register (ADRES)  
• A/D Control Register 0 (ADCON0)  
• A/D Control Register 1 (ADCON1)  
REGISTER 8-1:  
ADCON0 REGISTER (ADDRESS 1Fh)  
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0  
R/W-0 R/W-0  
R/W-0  
ADCS1 ADCS0 reserved CHS1  
CHS0 GO/DONE reserved ADON  
bit0  
R =Readable bit  
W = Writable bit  
bit7  
U =Unimplemented bit,  
read as ‘0’  
- n = Value at POR reset  
bit 7-6: ADCS<1:0>: A/D Conversion Clock Select bits  
00= FOSC/2  
01= FOSC/8  
10= FOSC/32  
11= FRC (clock derived from an RC oscillation)  
bit 5:  
Reserved  
bit 4-3: CHS<1:0>: Analog Channel Select bits  
00= channel 0, (GP0/AN0)  
01= channel 1, (GP1/AN1)  
10= channel 2, (GP2/AN2)  
11= channel 3, (GP4/AN3)  
bit 2:  
GO/DONE: A/D Conversion Status bit  
If ADON = 1  
1= A/D conversion in progress (setting this bit starts the A/D conversion)  
0= A/D conversion not in progress (this bit is automatically cleared by hardware when the A/D conversion  
is complete)  
bit 1:  
bit 0:  
Reserved  
ADON: A/D on bit  
1= A/D converter module is operating  
0= A/D converter module is shut off and consumes no operating current  
1999 Microchip Technology Inc.  
DS30561B-page 45  
PIC12C67X  
REGISTER 8-2:  
ADCON1 REGISTER (ADDRESS 9Fh)  
U-0  
U-0  
U-0  
U-0  
U-0  
R/W-0  
R/W-0  
R/W-0  
PCFG2  
PCFG1  
PCFG0  
R =Readable bit  
W = Writable bit  
bit7  
bit0  
U =Unimplemented bit,  
read as ‘0’  
- n =Value at POR reset  
bit 7-2: Unimplemented: Read as '0'  
bit 1-0: PCFG<2:0>: A/D Port Configuration Control bits  
PCFG<2:0>  
GP4  
GP2  
GP1  
GP0  
VREF  
000(1)  
001  
010  
011  
100  
101  
110  
111  
A
A
A
A
VDD  
A
D
D
D
D
D
D
A
A
A
D
D
D
D
VREF  
A
A
A
A
A
A
A
D
GP1  
VDD  
GP1  
VDD  
GP1  
VDD  
VDD  
VREF  
A
VREF  
D
D
A = Analog input  
D = Digital I/O  
Note 1: Value on reset.  
2: Any instruction that reads a pin configured as an analog input will read a '0'.  
DS30561B-page 46  
1999 Microchip Technology Inc.  
PIC12C67X  
The ADRES Register contains the result of the A/D  
conversion. When the A/D conversion is complete, the  
result is loaded into the ADRES register, the GO/DONE  
bit (ADCON0<2>) is cleared, and A/D interrupt flag bit  
ADIF (PIE1<6>) is set. The block diagrams of the A/D  
module are shown in Figure 8-1.  
2. Configure A/D interrupt (if desired):  
• Clear ADIF bit  
• Set ADIE bit  
• Set GIE bit  
3. Wait the required acquisition time.  
4. Start conversion:  
After the A/D module has been configured as desired,  
the selected channel must be acquired before the con-  
version is started. The analog input channels must  
have their corresponding TRIS bits selected as an  
input. To determine sample time, see Section 8.1. After  
this acquisition time has elapsed, the A/D conversion  
can be started. The following steps should be followed  
for doing an A/D conversion:  
• Set GO/DONE bit (ADCON0)  
5. Wait for A/D conversion to complete, by either:  
• Polling for the GO/DONE bit to be cleared  
OR  
• Waiting for the A/D interrupt  
6. Read A/D Result Register (ADRES), clear bit  
ADIF if required.  
1. Configure the A/D module:  
7. For the next conversion, go to step 1, step 2 or  
step 3 as required. The A/D conversion time per  
bit is defined as TAD. A minimum wait of 2TAD is  
required before next acquisition starts.  
• Configure analog pins / voltage reference /  
and digital I/O (ADCON1 and TRIS)  
• Select A/D input channel (ADCON0)  
• Select A/D conversion clock (ADCON0)  
Turn on A/D module (ADCON0)  
FIGURE 8-1: A/D BLOCK DIAGRAM  
CHS<1:0>  
11  
GP4/AN3  
VIN  
10  
(Input voltage)  
GP2/AN2  
01  
A/D  
Converter  
GP1/AN1/VREF  
00  
GP0/AN0  
VDD  
VREF  
(Reference  
voltage)  
PCFG<2:0>  
1999 Microchip Technology Inc.  
DS30561B-page 47  
PIC12C67X  
8.1  
A/D Sampling Requirements  
Note 1: The reference voltage (VREF) has no  
effect on the equation, since it cancels  
itself out.  
For the A/D converter to meet its specified accuracy,  
the charge holding capacitor (CHOLD) must be allowed  
to fully charge to the input channel voltage level. The  
analog input model is shown in Figure 8-2. The source  
impedance (RS) and the internal sampling switch (RSS)  
impedance directly affect the time required to charge  
the capacitor CHOLD. The sampling switch (RSS)  
impedance varies over the device voltage (VDD), see  
Figure 8-2. The maximum recommended imped-  
ance for analog sources is 10 k. After the analog  
input channel is selected (changed), this acquisition  
must be done before the conversion can be started.  
2: The charge holding capacitor (CHOLD) is  
not discharged after each conversion.  
3: The maximum recommended impedance  
for analog sources is 10 k. This is  
required to meet the pin leakage specifi-  
cation.  
4: After a conversion has completed, a  
2.0 TAD delay must complete before  
acquisition can begin again. During this  
time, the holding capacitor is not con-  
nected to the selected A/D input channel.  
To calculate the minimum acquisition time, Equation 8-1  
may be used. This equation assumes that 1/2 LSb error  
is used (512 steps for the A/D). The 1/2 LSb error is the  
maximum error allowed for the A/D to meet its specified  
resolution.  
EXAMPLE 8-1: CALCULATING THE  
MINIMUM REQUIRED  
SAMPLE TIME  
EQUATION 8-1:  
A/D MINIMUM CHARGING  
TIME  
TACQ = Internal Amplifier Settling Time +  
Holding Capacitor Charging Time +  
Temperature Coefficient  
(-Tc/CHOLD(RIC + RSS + RS))  
VHOLD = (VREF - (VREF/512)) • (1 - e  
)
or  
TACQ = 5 µs + Tc + [(Temp - 25°C)(0.05 µs/°C)]  
Tc = -(51.2 pF)(1 k+ RSS + RS) ln(1/511)  
TC =  
-CHOLD (RIC + RSS + RS) ln(1/512)  
-51.2 pF (1 k+ 7 k+ 10 k) ln(0.0020)  
-51.2 pF (18 k) ln(0.0020)  
-0.921 µs (-6.2146)  
Example 8-1 shows the calculation of the minimum  
required acquisition time TACQ. This calculation is  
based on the following system assumptions.  
Rs = 10 kΩ  
1/2 LSb error  
5.724 µs  
VDD = 5V Rss = 7 kΩ  
Temp (system max.) = 50°C  
VHOLD = 0 @ t = 0  
TACQ = 5 µs + 5.724 µs + [(50°C - 25°C)(0.05 µs/°C)]  
10.724 µs + 1.25 µs  
11.974 µs  
FIGURE 8-2: ANALOG INPUT MODEL  
VDD  
Sampling  
Switch  
VT = 0.6V  
RAx  
SS  
RIC 1k  
Rss  
Rs  
CHOLD  
= DAC capacitance  
= 51.2 pF  
CPIN  
5 pF  
VA  
I leakage  
± 500 nA  
VT = 0.6V  
VSS  
Legend: CPIN  
VT  
= input capacitance  
= threshold voltage  
6V  
5V  
VDD 4V  
3V  
I leakage = leakage current at the pin due to  
various junctions  
2V  
RIC  
SS  
= interconnect resistance  
= sampling switch  
CHOLD  
= sample/hold capacitance (from DAC)  
5 6 7 8 9 10 11  
Sampling Switch  
( k)  
DS30561B-page 48  
1999 Microchip Technology Inc.  
PIC12C67X  
8.2  
Selecting the A/D Conversion Clock  
8.3  
Configuring Analog Port Pins  
The A/D conversion time per bit is defined as TAD. The  
A/D conversion requires 9.5 TAD per 8-bit conversion.  
The source of the A/D conversion clock is software  
selected. The four possible options for TAD are:  
The ADCON1 and TRIS Registers control the opera-  
tion of the A/D port pins. The port pins that are desired  
as analog inputs must have their corresponding TRIS  
bits set (input). If the TRIS bit is cleared (output), the  
digital output level (VOH or VOL) will be converted.  
• 2TOSC  
The A/D operation is independent of the state of the  
CHS<2:0> bits and the TRIS bits.  
• 8TOSC  
• 32TOSC  
• Internal ADC RC oscillator  
Note 1: When reading the port register, all pins  
configured as analog input channel will  
read as cleared (a low level). Pins config-  
ured as digital inputs, will convert an ana-  
log input. Analog levels on a digitally  
configured input will not affect the conver-  
sion accuracy.  
For correct A/D conversions, the A/D conversion clock  
(TAD) must be selected to ensure a minimum TAD time  
of 1.6 µs. If the minimum TAD time of 1.6 µs can not be  
obtained, TAD should be 8 µs for preferred operation.  
Table 8-1 shows the resultant TAD times derived from  
the device operating frequencies and the A/D clock  
source selected.  
2: Analog levels on any pin that is defined as  
a digital input (including the AN<3:0>  
pins) may cause the input buffer to con-  
sume current that is out of the devices  
specification.  
TABLE 8-1:  
TAD vs. DEVICE OPERATING FREQUENCIES  
Device Frequency  
AD Clock Source (TAD)  
ADCS<1:0>  
Operation  
2TOSC  
4 MHz  
1.25 MHz  
1.6 µs  
333.33 kHz  
500 ns(2)  
00  
01  
10  
11  
6 µs  
24 µs(3)  
96 µs(3)  
2 - 6 µs(1)  
8TOSC  
2.0 µs  
6.4 µs  
25.6 µs(3)  
2 - 6 µs(1,4)  
32TOSC  
8.0 µs  
Internal ADC RC Oscillator(5)  
2 - 6 µs(1,4)  
Note 1: The RC source has a typical TAD time of 4 µs.  
2: These values violate the minimum required TAD time.  
3: For faster conversion times, the selection of another clock source is recommended.  
4: While in RC mode, with device frequency above 1 MHz, conversion accuracy is out of specification.  
5: For extended voltage devices (LC), please refer to Electrical Specifications section.  
1999 Microchip Technology Inc.  
DS30561B-page 49  
PIC12C67X  
Clearing the GO/DONE bit during a conversion will  
abort the current conversion. The ADRES register will  
NOT be updated with the partially completed A/D con-  
version sample. That is, the ADRES register will con-  
tinue to contain the value of the last completed  
conversion (or the last value written to the ADRES reg-  
ister). After the A/D conversion is aborted, a 2TAD wait  
is required before the next acquisition is started. After  
this 2TAD wait, an acquisition is automatically started on  
the selected channel.  
8.4  
A/D Conversions  
Example 8-2 shows how to perform an A/D conversion.  
The GPIO pins are configured as analog inputs. The  
analog reference (VREF) is the device VDD. The A/D  
interrupt is enabled and the A/D conversion clock is  
FRC. The conversion is performed on the GP0 channel.  
Note: The GO/DONE bit should NOT be set in  
the same instruction that turns on the A/D.  
EXAMPLE 8-2: DOING AN A/D CONVERSION  
BSF  
CLRF  
BSF  
STATUS, RP0  
ADCON1  
; Select Page 1  
; Configure A/D inputs  
; Enable A/D interrupts  
; Select Page 0  
; RC Clock, A/D is on, Channel 0 is selected  
;
; Clear A/D interrupt flag bit  
; Enable peripheral interrupts  
; Enable all interrupts  
PIE1,  
ADIE  
BCF  
STATUS, RP0  
0xC1  
ADCON0  
MOVLW  
MOVWF  
BCF  
BSF  
BSF  
PIR1,  
ADIF  
INTCON, PEIE  
INTCON, GIE  
;
;
;
;
Ensure that the required sampling time for the selected input channel has elapsed.  
Then the conversion may be started.  
BSF  
:
ADCON0, GO  
; Start A/D Conversion  
; The ADIF bit will be set and the GO/DONE bit  
:
;
is cleared upon completion of the A/D Conversion.  
DS30561B-page 50  
1999 Microchip Technology Inc.  
PIC12C67X  
8.5  
A/D Operation During Sleep  
8.7  
Effects of a Reset  
The A/D module can operate during SLEEP mode. This  
requires that the A/D clock source be set to RC  
(ADCS<1:0> = 11). When the RC clock source is  
selected, the A/D module waits one instruction cycle  
before starting the conversion. This allows the SLEEP  
instruction to be executed, which eliminates all digital  
switching noise from the conversion. When the conver-  
sion is completed, the GO/DONE bit will be cleared,  
and the result loaded into the ADRES Register. If the  
A/D interrupt is enabled, the device will wake-up from  
SLEEP. If the A/D interrupt is not enabled, the A/D mod-  
ule will then be turned off, although the ADON bit will  
remain set.  
A device reset forces all registers to their reset state.  
This forces the A/D module to be turned off, and any  
conversion is aborted. The value that is in the ADRES  
register is not modified for a Reset. The ADRES regis-  
ter will contain unknown data after a Power-on Reset.  
8.8  
Connection Considerations  
If the input voltage exceeds the rail values (VSS or VDD)  
by greater than 0.2V, then the accuracy of the conver-  
sion is out of specification.  
Note: For the PIC12C67X, care must be taken  
when using the GP4 pin in A/D conversions  
due to its proximity to the OSC1 pin.  
When the A/D clock source is another clock option (not  
RC), a SLEEPinstruction will cause the present conver-  
sion to be aborted and the A/D module to be turned off,  
though the ADON bit will remain set.  
An external RC filter is sometimes added for anti-  
aliasing of the input signal. The R component should be  
selected to ensure that the total source impedance is  
kept under the 10 krecommended specification. Any  
external components connected (via hi-impedance) to  
an analog input pin (capacitor, zener diode, etc.) should  
have very little leakage current at the pin.  
Turning off the A/D places the A/D module in its lowest  
current consumption state.  
Note: For the A/D module to operate in SLEEP,  
the A/D clock source must be set to RC  
(ADCS<1:0> = 11). To perform an A/D  
conversion in SLEEP, the GO/DONE bit  
must be set, followed by the SLEEP  
instruction.  
8.9  
Transfer Function  
The ideal transfer function of the A/D converter is as fol-  
lows: the first transition occurs when the analog input  
voltage (VAIN) is 1 LSb (or Analog VREF / 256)  
(Figure 8-3).  
8.6  
A/D Accuracy/Error  
FIGURE 8-3: A/D TRANSFER FUNCTION  
The overall accuracy of the A/D is less than ± 1 LSb for  
VDD = 5V ± 10% and the analog VREF = VDD. This over-  
all accuracy includes offset error, full scale error, and  
integral error. The A/D converter is monotonic over the  
full VDD range. The resolution and accuracy may be  
less when either the analog reference (VDD) is less than  
5.0V or when the analog reference (VREF) is less than  
VDD.  
FFh  
FEh  
The maximum pin leakage current is specified in the  
Device Data Sheet electrical specification, parameter  
#D060.  
04h  
03h  
02h  
01h  
00h  
In systems where the device frequency is low, use of  
the A/D RC clock is preferred. At moderate to high fre-  
quencies, TAD should be derived from the device oscil-  
lator. TAD must not violate the minimum and should be  
8 µs for preferred operation. This is because TAD,  
when derived from TOSC, is kept away from on-chip  
phase clock transitions. This reduces, to a large extent,  
the effects of digital switching noise. This is not possible  
with the RC derived clock. The loss of accuracy due to  
digital switching noise can be significant if many I/O  
pins are active.  
Analog input voltage  
In systems where the device will enter SLEEP mode  
after the start of the A/D conversion, the RC clock  
source selection is required. In this mode, the digital  
noise from the modules in SLEEP are stopped. This  
method gives high accuracy.  
1999 Microchip Technology Inc.  
DS30561B-page 51  
PIC12C67X  
FIGURE 8-4: FLOWCHART OF A/D OPERATION  
ADON = 0  
Yes  
ADON = 0?  
No  
Acquire  
Selected Channel  
Yes  
GO = 0?  
No  
Yes  
Yes  
Start of A/D  
Conversion Delayed  
1 Instruction Cycle  
Finish Conversion  
SLEEP  
Instruction?  
A/D Clock  
= RC?  
GO = 0  
ADIF = 1  
No  
No  
Yes  
Yes  
Abort Conversion  
GO = 0  
Wake-up  
From Sleep?  
Finish Conversion  
Device in  
SLEEP?  
Wait 2 TAD  
GO = 0  
ADIF = 1  
ADIF = 0  
No  
No  
SLEEP  
Power-down A/D  
Finish Conversion  
Stay in Sleep  
Power-down A/D  
Wait 2 TAD  
GO = 0  
ADIF = 1  
Wait 2 TAD  
TABLE 8-2:  
SUMMARY OF A/D REGISTERS  
Value on  
Power-on  
Reset  
Value on  
all other  
Resets  
Address Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(1)  
0Bh/8Bh INTCON  
GIE  
PEIE  
T0IE  
INTE GPIE  
T0IF  
INTF  
GPIF  
0000 000x 0000 000u  
-0-- ---- -0-- ----  
PIR1  
ADIF  
0Ch  
8Ch  
1Eh  
1Fh  
9Fh  
05h  
85h  
PIE1  
ADIE  
-0-- ---- -0-- ----  
xxxx xxxx uuuu uuuu  
ADRES  
A/D Result Register  
ADCON0  
ADCON1  
ADCS1 ADCS0 reserved CHS1 CHS0 GO/DONE reserved ADON 0000 0000 0000 0000  
PCFG2  
PCFG1 PCFG0 ---- -000 ---- -000  
(2)  
(2)  
11xx xxxx 11uu uuuu  
--11 1111 --11 1111  
GPIO  
TRIS  
SCL  
SDA  
GP5  
GP4  
GP3  
GP2  
GP1  
GP0  
TRIS5 TRIS4 TRIS3  
TRIS2  
TRIS1  
TRIS0  
Legend: x= unknown, u= unchanged, -= unimplemented read as '0'. Shaded cells are not used for A/D conversion.  
Note 1: These registers can be addressed from either bank.  
2: The SCL (GP7) and SDA (GP6) bits are unimplemented on the PIC12C671/672 and read as ’0’.  
DS30561B-page 52  
1999 Microchip Technology Inc.  
PIC12C67X  
the chip in reset until the crystal oscillator is stable. The  
other is the Power-up Timer (PWRT), which provides a  
fixed delay of 72 ms (nominal) on power-up only,  
designed to keep the part in reset while the power sup-  
ply stabilizes. With these two timers on-chip, most  
applications need no external reset circuitry.  
9.0  
SPECIAL FEATURES OF THE  
CPU  
What sets a microcontroller apart from other proces-  
sors are special circuits to deal with the needs of real-  
time applications. The PIC12C67X family has a host of  
such features intended to maximize system reliability,  
minimize cost through elimination of external compo-  
nents, provide power saving operating modes and offer  
code protection. These are:  
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, or  
through an interrupt. Several oscillator options are also  
made available to allow the part to fit the application.  
The INTRC/EXTRC oscillator option saves system  
cost, while the LP crystal option saves power. A set of  
configuration bits are used to select various options.  
• Oscillator selection  
• Reset  
- Power-on Reset (POR)  
- Power-up Timer (PWRT)  
- Oscillator Start-up Timer (OST)  
• Interrupts  
9.1  
Configuration Bits  
The configuration bits can be programmed (read as '0')  
or left unprogrammed (read as '1') to select various  
device configurations. These bits are mapped in pro-  
gram memory location 2007h.  
• Watchdog Timer (WDT)  
• SLEEP  
• Code protection  
• ID locations  
The user will note that address 2007h is beyond the  
user program memory space. In fact, it belongs to the  
special test/configuration memory space (2000h-  
3FFFh), which can be accessed only during  
programming.  
• In-circuit serial programming  
The PIC12C67X has a Watchdog Timer, which can be  
shut off only through configuration bits. It runs off its  
own RC oscillator for added reliability. There are two  
timers that offer necessary delays on power-up. One is  
the Oscillator Start-up Timer (OST), intended to keep  
REGISTER 9-1:  
CONFIGURATION WORD  
CP1 CP0 CP1 CP0 CP1 CP0 MCLRE CP1  
bit13  
CP0 PWRTE WDTE FOSC2 FOSC1 FOSC0  
bit0  
Register: CONFIG  
Address 2007h  
(1)  
bit 13-8, CP<1:0>: Code Protection bit pairs  
6-5: 11= Code protection off  
10= Locations 400h through 7FEh code protected (do not use for PIC12C671 and PIC12CE673)  
01= Locations 200h through 7FEh code protected  
00= All memory is code protected  
bit 7:  
bit 4:  
bit 3:  
MCLRE: Master Clear Reset Enable bit  
1 = Master Clear Enabled  
0 = Master Clear Disabled  
PWRTE: Power-up Timer Enable bit  
1 = PWRT disabled  
0 = PWRT enabled  
WDTE: Watchdog Timer Enable bit  
1 = WDT enabled  
0 = WDT disabled  
bit 2-0: FOSC<2:0>: Oscillator Selection bits  
111= EXTRC, Clockout on OSC2  
110= EXTRC, OSC2 is I/O  
101= INTRC, Clockout on OSC2  
100= INTRC, OSC2 is I/O  
011= Invalid Selection  
010= HS Oscillator  
001= XT Oscillator  
000= LP Oscillator  
Note 1: All of the CP<1:0> pairs have to be given the same value to enable the code protection scheme listed.  
1999 Microchip Technology Inc.  
DS30561B-page 53  
PIC12C67X  
9.2  
Oscillator Configurations  
OSCILLATOR TYPES  
TABLE 9-1:  
CAPACITOR SELECTION  
FOR CERAMIC RESONATORS  
- PIC12C67X  
9.2.1  
The PIC12C67X can be operated in seven different  
oscillator modes. The user can program three  
configuration bits (FOSC<2:0>) to select one of these  
seven modes:  
Osc  
Type  
Resonator Cap. Range Cap. Range  
Freq  
C1  
C2  
XT  
455 kHz  
2.0 MHz  
4.0 MHz  
22-100 pF  
15-68 pF  
15-68 pF  
22-100 pF  
15-68 pF  
15-68 pF  
• LP:  
• HS:  
• XT:  
Low Power Crystal  
High Speed Crystal/Resonator  
Crystal/Resonator  
HS  
4.0 MHz  
8.0 MHz  
10.0 MHz  
15-68 pF  
10-68 pF  
10-22 pF  
15-68 pF  
10-68 pF  
10-22 pF  
• INTRC*: Internal 4 MHz Oscillator  
• EXTRC*: External Resistor/Capacitor  
These values are for design guidance only. Since  
each resonator has its own characteristics, the user  
should consult the resonator manufacturer for  
appropriate values of external components.  
*Can be configured to support CLKOUT  
9.2.2  
CRYSTAL OSCILLATOR / CERAMIC  
RESONATORS  
TABLE 9-2:  
CAPACITOR SELECTION  
FOR CRYSTAL OSCILLATOR  
- PIC12C67X  
In XT, HS or LP modes, a crystal or ceramic resonator  
is connected to the GP5/OSC1/CLKIN and GP4/OSC2  
pins to establish oscillation (Figure 9-1). The  
PIC12C67X oscillator design requires the use of a  
parallel cut crystal. Use of a series cut crystal may give  
Osc  
Type  
Resonator Cap. Range Cap. Range  
Freq  
C1  
C2  
LP  
32 kHz(1)  
100 kHz  
200 kHz  
15 pF  
15-30 pF  
15-30 pF  
15 pF  
30-47 pF  
15-82 pF  
a
frequency out of the crystal manufacturers  
specifications. When in XT, HS or LP modes, the  
device can have an external clock source drive the  
GP5/OSC1/CLKIN pin (Figure 9-2).  
XT  
100 kHz  
200 kHz  
455 kHz  
1 MHz  
2 MHz  
4 MHz  
15-30 pF  
15-30 pF  
15-30 pF  
15-30 pF  
15-30 pF  
15-47 pF  
200-300 pF  
100-200 pF  
15-100 pF  
15-30 pF  
15-30 pF  
15-47 pF  
FIGURE 9-1: CRYSTAL OPERATION  
(OR CERAMIC RESONATOR)  
(XT, HS OR LP OSC  
CONFIGURATION)  
HS  
4 MHz  
8 MHz  
10 MHz  
15-30 pF  
15-30 pF  
15-30 pF  
15-30 pF  
15-30 pF  
15-30 pF  
(1)  
C1  
OSC1  
PIC12C67X  
Note 1: For VDD > 4.5V, C1 = C2 30 pF is  
SLEEP  
recommended.  
XTAL  
(3)  
RF  
To internal  
logic  
These values are for design guidance only. Rs may  
be required in HS mode, as well as XT mode, to  
avoid overdriving crystals with low drive level specifi-  
cation. Since each crystal has its own characteris-  
tics, the user should consult the crystal manufacturer  
for appropriate values of external components.  
OSC2  
(2)  
RS  
(1)  
C2  
Note 1: See Capacitor Selection tables for  
recommended values of C1 and C2.  
2: A series resistor (RS) may be required for AT  
strip cut crystals.  
3: RF varies with the oscillator mode selected  
(approx. value = 10 M).  
FIGURE 9-2: EXTERNAL CLOCK INPUT  
OPERATION (XT, HS OR LP  
OSC CONFIGURATION)  
OSC1  
OSC2  
Clock from  
ext. system  
PIC12C67X  
Open  
DS30561B-page 54  
1999 Microchip Technology Inc.  
PIC12C67X  
9.2.3  
EXTERNAL CRYSTAL OSCILLATOR  
CIRCUIT  
9.2.4  
EXTERNAL RC OSCILLATOR  
For timing insensitive applications, the RC device  
option offers additional cost savings. The RC oscillator  
frequency is a function of the supply voltage, the  
resistor (REXT) and capacitor (CEXT) values, and the  
operating temperature. In addition to this, the oscillator  
frequency will vary from unit to unit due to normal  
process parameter variation. Furthermore, the  
difference in lead frame capacitance between package  
types will also affect the oscillation frequency,  
especially for low CEXT values. The user also needs to  
take into account variation due to tolerance of external  
R and C components used.  
Either a pre-packaged oscillator or a simple oscillator  
circuit with TTL gates can be used as an external  
crystal oscillator circuit. Pre-packaged oscillators  
provide a wide operating range and better stability. A  
well-designed crystal oscillator will provide good  
performance with TTL gates. Two types of crystal  
oscillator circuits can be used; one with parallel  
resonance or one with series resonance.  
Figure 9-3 shows implementation of  
a
parallel  
resonant oscillator circuit. The circuit is designed to  
use the fundamental frequency of the crystal. The  
74AS04 inverter performs the 180-degree phase shift  
that a parallel oscillator requires. The 4.7 kresistor  
provides the negative feedback for stability. The 10 kΩ  
potentiometers bias the 74AS04 in the linear region.  
This circuit could be used for external oscillator  
designs.  
Figure 9-5 shows how the R/C combination is  
connected to the PIC12C67X. For REXT values below  
2.2 k, the oscillator operation may become unstable  
or stop completely. For very high REXT values  
(i.e., 1 M), the oscillator becomes sensitive to noise,  
humidity and leakage. Thus, we recommend keeping  
REXT between 3 kand 100 k.  
FIGURE 9-3: EXTERNAL PARALLEL  
RESONANT CRYSTAL  
Although the oscillator will operate with no external  
capacitor (CEXT = 0 pF), we recommend using values  
above 20 pF for noise and stability reasons. With no or  
small external capacitance, the oscillation frequency  
can vary dramatically due to changes in external  
capacitances, such as PCB trace capacitance or  
package lead frame capacitance.  
OSCILLATOR CIRCUIT  
+5V  
To Other  
Devices  
10k  
74AS04  
PIC12C67X  
4.7k  
74AS04  
CLKIN  
The variation is larger for larger R (since leakage  
current variation will affect RC frequency more for  
large R) and for smaller C (since variation of input  
capacitance will affect RC frequency more).  
10k  
XTAL  
FIGURE 9-5: EXTERNAL RC OSCILLATOR  
MODE  
10k  
VDD  
20 pF  
20 pF  
REXT  
Internal  
clock  
OSC1  
N
Figure 9-4 shows a series resonant oscillator circuit.  
This circuit is also designed to use the fundamental  
frequency of the crystal. The inverter performs a 180-  
degree phase shift in a series resonant oscillator  
circuit. The 330 resistors provide the negative  
feedback to bias the inverters in their linear region.  
CEXT  
VSS  
PIC12C67X  
OSC2/CLKOUT  
FOSC/4  
FIGURE 9-4: EXTERNAL SERIES  
RESONANT CRYSTAL  
OSCILLATOR CIRCUIT  
To Other  
Devices  
330  
330  
74AS04  
74AS04  
74AS04  
PIC12C67X  
CLKIN  
0.1 µF  
XTAL  
1999 Microchip Technology Inc.  
DS30561B-page 55  
PIC12C67X  
9.2.5  
INTERNAL 4 MHz RC OSCILLATOR  
9.3  
Reset  
The PIC12C67X differentiates between various kinds  
of reset:  
The internal RC oscillator provides a fixed 4 MHz (nom-  
inal) system clock at VDD = 5V and 25°C. See  
Section 13.0 for information on variation over voltage  
and temperature.  
• Power-on Reset (POR)  
• MCLR Reset during normal operation  
• MCLR Reset during SLEEP  
• WDT Reset (normal operation)  
In addition, a calibration instruction is programmed into  
the last address of the program memory which contains  
the calibration value for the internal RC oscillator. This  
value is programmed as a RETLW XXinstruction where  
XX is the calibration value. In order to retrieve the cali-  
bration value, issue a CALL YYinstruction where YY is  
the last location in program memory (03FFh for the  
PIC12C671 and the PIC12CE673, 07FFh for the  
PIC12C672 and the PIC12CE674). Control will be  
returned to the user’s program with the calibration  
value loaded into the W register. The program should  
then perform a MOVWF OSCCALinstruction to load the  
value into the internal RC oscillator trim register.  
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 Power-on Reset (POR), MCLR Reset, WDT  
Reset, and MCLR Reset during SLEEP. They are not  
affected by a WDT Wake-up, which is viewed as the  
resumption of normal operation. The TO and PD bits  
are set or cleared differently in different reset situations,  
as indicated in Table 9-5. These bits are used in  
software to determine the nature of the reset. See  
Table 9-6 for a full description of reset states of all  
registers.  
OSCCAL, when written to with the calibration value, will  
“trim” the internal oscillator to remove process variation  
from the oscillator frequency. Bits <7:4>, CAL<3:0> are  
used for fine calibration, while bit 3, CALFST, and bit 2,  
CALSLW, are used for more coarse adjustment. Adjust-  
ing CAL<3:0> from 0000 to 1111 yields a higher clock  
speed. Set CALFST = 1 for greater increase in fre-  
quency or set CALSLW = 1 for greater decrease in fre-  
quency. Note that bits 1 and 0 of OSCCAL are  
unimplemented and should be written as 0 when mod-  
ifying OSCCAL for compatibility with future devices.  
A simplified block diagram of the on-chip reset circuit is  
shown in Figure 9-6.  
The PIC12C67X has a MCLR 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.  
When MCLR is asserted, the state of the OSC1/CLKIN  
and CLKOUT/OSC2 pins are as follows:  
Note: Please note that erasing the device will  
also erase the pre-programmed internal  
calibration value for the internal oscillator.  
The calibration value must be saved prior  
to erasing the part.  
TABLE 9-3:  
CLKIN/CLKOUT PIN STATES  
WHEN MCLR ASSERTED  
Oscillator Mode OSC1/CLKIN Pin OSC2/CLKout Pin  
EXTRC, CLKOUT OSC1 pin is  
on OSC2  
OSC2 pin is driven  
low  
tristated and  
driven by external  
circuit  
9.2.6  
CLKOUT  
The PIC12C67X can be configured to provide a clock  
out signal (CLKOUT) on pin 3 when the configuration  
word address (2007h) is programmed with FOSC2,  
FOSC1, and FOSC0, equal to 101 for INTRC or 111 for  
EXTRC. The oscillator frequency, divided by 4, can be  
used for test purposes or to synchronize other logic.  
EXTRC, OSC2 is OSC1 pin is  
OSC2 pin is  
tristate input  
I/O  
tristated and  
driven by external  
circuit  
INTRC, CLKOUT OSC1 pin is  
OSC2 pin is driven  
low  
on OSC2  
tristate input  
INTRC, OSC2 is  
I/O  
OSC1 pin is  
tristate input  
OSC2 pin is  
tristate input  
DS30561B-page 56  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 9-6: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT  
Weak  
Pull-up  
GP3/MCLR/VPP Pin  
MCLRE  
INTERNAL MCLR  
WDT  
Module  
SLEEP  
WDT Time-out  
VDD rise  
detect  
Power-on Reset  
VDD  
S
OST/PWRT  
OST  
Chip_Reset  
10-bit Ripple-counter  
R
Q
OSC1/  
CLKIN  
Pin  
PWRT  
(1)  
On-chip  
RC OSC  
10-bit Ripple-counter  
Enable PWRT  
Enable OST  
See Table 9-4 for time-out situations.  
Note 1: This is a separate oscillator from the RC oscillator of the CLKIN pin.  
1999 Microchip Technology Inc.  
DS30561B-page 57  
PIC12C67X  
9.4.3  
OSCILLATOR START-UP TIMER (OST)  
9.4  
Power-on Reset (POR), Power-up  
Timer (PWRT) and Oscillator Start-up  
Timer (OST)  
The Oscillator Start-up Timer (OST) provides 1024  
oscillator cycle (from OSC1 input) delay after the  
PWRT delay is over. This ensures that the crystal oscil-  
lator or resonator has started and stabilized.  
9.4.1  
POWER-ON RESET (POR)  
The on-chip POR circuit holds the chip in reset until  
VDD has reached a high enough level for proper opera-  
tion. To take advantage of the POR, just tie the MCLR  
pin through a resistor to VDD. This will eliminate exter-  
nal RC components usually needed to create a Power-  
on Reset. A maximum rise time for VDD is specified.  
See Electrical Specifications for details.  
The OST time-out is invoked only for XT, LP and HS  
modes and only on Power-on Reset or wake-up from  
SLEEP.  
9.4.4  
TIME-OUT SEQUENCE  
On power-up, the Time-out Sequence is as follows:  
first, PWRT time-out is invoked after the POR time  
delay has expired; then, OST is activated. The total  
time-out will vary, based on oscillator configuration and  
the status of the PWRT. For example, in RC mode with  
the PWRT disabled, there will be no time-out at all.  
Figure 9-7, Figure 9-8, and Figure 9-9 depict time-out  
sequences on power-up.  
When the device starts normal operation (exits the  
reset condition), device operating parameters (voltage,  
frequency, temperature, ...) must be met to ensure  
operation. If these conditions are not met, the device  
must be held in reset until the operating conditions are  
met.  
For additional information, refer to Application Note  
AN607, "Power-up Trouble Shooting."  
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  
(Figure 9-9). This is useful for testing purposes or to  
synchronize more than one PIC12C67X device operat-  
ing in parallel.  
9.4.2  
POWER-UP TIMER (PWRT)  
The Power-up Timer provides a fixed 72 ms nominal  
time-out on power-up only, from the POR. The Power-  
up Timer operates on an internal RC oscillator. The  
chip is kept in reset as long as the PWRT is active. The  
PWRT’s time delay allows VDD to rise to an acceptable  
level. A configuration bit is provided to enable/disable  
the PWRT.  
9.4.5  
POWER CONTROL (PCON)/STATUS  
REGISTER  
The Power Control/Status Register, PCON (address  
8Eh), has one bit. See Register 4-6 for register.  
The power-up time delay will vary from chip to chip due  
to VDD, temperature and process variation. See  
Table 11-4.  
Bit1 is POR (Power-on Reset). It is cleared on a Power-  
on Reset and is unaffected otherwise. The user sets  
this bit following a Power-on Reset. On subsequent  
resets, if POR is ‘0’, it will indicate that a Power-on  
Reset must have occurred.  
TABLE 9-4:  
TIME-OUT IN VARIOUS SITUATIONS  
Oscillator Configuration  
Power-up  
Wake-up from SLEEP  
PWRTE = 0 PWRTE = 1  
XT, HS, LP  
72 ms + 1024TOSC  
1024TOSC  
1024TOSC  
INTRC, EXTRC  
72 ms  
TABLE 9-5:  
STATUS/PCON BITS AND THEIR SIGNIFICANCE  
PD  
POR  
TO  
0
0
0
1
1
1
1
1
0
x
0
0
u
1
1
x
0
u
0
u
0
Power-on Reset  
Illegal, TO is set on POR  
Illegal, PD is set on POR  
WDT Reset  
WDT Wake-up  
MCLR Reset during normal operation  
MCLR Reset during SLEEP or interrupt wake-up from SLEEP  
Legend: u= unchanged, x= unknown.  
DS30561B-page 58  
1999 Microchip Technology Inc.  
PIC12C67X  
TABLE 9-6:  
RESET CONDITION FOR SPECIAL REGISTERS  
Program  
Counter  
STATUS  
Register  
PCON  
Register  
Condition  
Power-on Reset  
000h  
0001 1xxx  
000u uuuu  
0001 0uuu  
0000 uuuu  
uuu0 0uuu  
uuu1 0uuu  
---- --0-  
---- --u-  
---- --u-  
---- --u-  
---- --u-  
---- --u-  
MCLR Reset during normal operation  
MCLR Reset during SLEEP  
000h  
000h  
WDT Reset during normal operation  
WDT Wake-up from SLEEP  
000h  
PC + 1  
PC + 1(1)  
Interrupt wake-up from SLEEP  
Legend: u= unchanged, x= unknown, -= unimplemented bit read as ’0’.  
Note 1: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h).  
TABLE 9-7:  
Register  
INITIALIZATION CON\DITIONS FOR ALL REGISTERS  
Power-on Reset  
MCLR Resets  
WDT Reset  
Wake-up via  
WDT or Interrupt  
W
xxxx xxxx  
0000 0000  
xxxx xxxx  
0000 0000  
0001 1xxx  
xxxx xxxx  
11xx xxxx  
uuuu uuuu  
0000 0000  
uuuu uuuu  
0000 0000  
000q quuu(3)  
uuuu uuuu  
11uu uuuu  
uuuu uuuu  
0000 0000  
uuuu uuuu  
PC + 1(2)  
INDF  
TMR0  
PCL  
STATUS  
FSR  
uuuq quuu(3)  
uuuu uuuu  
11uu uuuu  
GPIO  
PIC12CE67X  
GPIO  
--xx xxxx  
--uu uuuu  
--uu uuuu  
PIC12C67X  
PCLATH  
INTCON  
PIR1  
---0 0000  
0000 000x  
-0-- ----  
0000 0000  
1111 1111  
--11 1111  
-0-- ----  
---- --0-  
0111 00--  
---- -000  
---0 0000  
0000 000u  
-0-- ----  
0000 0000  
1111 1111  
--11 1111  
-0-- ----  
---- --u-  
uuuu uu--  
---- -000  
---u uuuu  
uuuu uqqq(1)  
-q-- ----(4)  
uuuu uquu(5)  
uuuu uuuu  
--uu uuuu  
-u-- ----  
---- --u-  
uuuu uu--  
---- -uuu  
ADCON0  
OPTION  
TRIS  
PIE1  
PCON  
OSCCAL  
ADCON1  
Legend:  
u
= unchanged,  
x = unknown, -= unimplemented bit, read as ’0’, q= value depends on condition.  
Note 1: One or more bits in INTCON and PIR1 will be affected (to cause wake-up).  
2: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h).  
3: See Table 9-5 for reset value for specific condition.  
4: If wake-up was due to A/D completing then bit 6 = 1, all other interrupts generating a wake-up will cause bit 6 = u.  
5: If wake-up was due to A/D completing then bit 3 = 0, all other interrupts generating a wake-up will cause bit 3 = u.  
1999 Microchip Technology Inc.  
DS30561B-page 59  
PIC12C67X  
FIGURE 9-7: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1  
VDD  
MCLR  
INTERNAL POR  
TPWRT  
PWRT TIME-OUT  
OST TIME-OUT  
TOST  
INTERNAL RESET  
FIGURE 9-8: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2  
VDD  
MCLR  
INTERNAL POR  
TPWRT  
PWRT TIME-OUT  
TOST  
OST TIME-OUT  
INTERNAL RESET  
FIGURE 9-9: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD)  
VDD  
MCLR  
INTERNAL POR  
TPWRT  
PWRT TIME-OUT  
TOST  
OST TIME-OUT  
INTERNAL RESET  
DS30561B-page 60  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 9-10: EXTERNAL POWER-ON  
RESET CIRCUIT (FOR SLOW  
VDD POWER-UP)  
FIGURE 9-11: EXTERNAL BROWN-OUT  
PROTECTION CIRCUIT 1  
VDD  
VDD  
33k  
VDD  
10k  
D
R
MCLR  
R1  
4.3k  
PIC12C67X  
MCLR  
PIC12C67X  
C
Note 1: This circuit will activate reset when VDD goes  
Note 1: External Power-on Reset circuit is required only  
if VDD power-up slope is too slow. The diode D  
helps discharge the capacitor quickly when VDD  
powers down.  
below (Vz + 0.7V), where Vz = Zener voltage.  
2: Resistors should be adjusted for the character-  
istics of the transistor.  
2: R < 40 kis recommended to make sure that  
voltage drop across R does not violate the  
device’s electrical specification.  
FIGURE 9-12: EXTERNAL BROWN-OUT  
PROTECTION CIRCUIT 2  
3: R1 = 100to 1 kwill limit any current flowing  
into MCLR from external capacitor C, in the  
event of MCLR/VPP pin breakdown due to  
Electrostatic Discharge (ESD) or Electrical  
Overstress (EOS).  
VDD  
VDD  
R1  
Q1  
MCLR  
R2  
4.3k  
PIC12C67X  
Note 1: This brown-out circuit is less expensive,  
albeit less accurate. Transistor Q1 turns off  
when VDD is below a certain level such that:  
R1  
= 0.7V  
VDD •  
R1 + R2  
2: Resistors should be adjusted for the charac-  
teristics of the transistor.  
1999 Microchip Technology Inc.  
DS30561B-page 61  
PIC12C67X  
The “return-from-interrupt” instruction, RETFIE, exits  
the interrupt routine, as well as sets the GIE bit, which  
re-enables interrupts.  
9.5  
Interrupts  
There are four sources of interrupt:  
Interrupt Sources  
The GP2/INT, GPIO port change interrupt and the  
TMR0 overflow interrupt flags are contained in the  
INTCON register.  
TMR0 Overflow Interrupt  
External Interrupt GP2/INT pin  
GPIO Port Change Interrupts (pins GP0, GP1, GP3)  
A/D Interrupt  
The peripheral interrupt flag ADIF, is contained in the  
Special Function Register PIR1. The corresponding  
interrupt enable bit is contained in Special Function  
Register PIE1, and the peripheral interrupt enable bit is  
contained in Special Function Register INTCON.  
The Interrupt Control Register (INTCON) records indi-  
vidual interrupt requests in flag bits. It also has individ-  
ual and global interrupt enable bits.  
When an interrupt is responded to, the GIE bit is  
cleared to disable any further interrupt, the return  
address is pushed onto the stack and the PC is loaded  
with 0004h. 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 repeated interrupts.  
Note: Individual interrupt flag bits are set, regard-  
less of the status of their corresponding  
mask bit or the GIE bit.  
A global interrupt enable bit, GIE (INTCON<7>),  
enables (if set) all un-masked interrupts or disables (if  
cleared) all interrupts. When bit GIE is enabled and an  
interrupt’s flag bit and mask bit are set, the interrupt will  
vector immediately. Individual interrupts can be dis-  
abled through their corresponding enable bits in vari-  
ous registers. Individual interrupt flag bits are set,  
regardless of the status of their corresponding mask bit  
or the GIE bit. The GIE bit is cleared on reset.  
For external interrupt events, such as GPIO change  
interrupt, the interrupt latency will be three or four  
instruction cycles. The exact latency depends on when  
the interrupt event occurs (Figure 9-14). The latency is  
the same for one or two cycle instructions. Individual  
interrupt flag bits are set, regardless of the status of  
their corresponding mask bit or the GIE bit.  
FIGURE 9-13: INTERRUPT LOGIC  
Wake-up  
(If in SLEEP mode)  
T0IF  
T0IE  
INTF  
INTE  
Interrupt to CPU  
GPIF  
GPIE  
PEIE  
ADIF  
ADIE  
GIE  
DS30561B-page 62  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 9-14: 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  
CLKOUT  
3
4
INT pin  
1
1
Interrupt Latency  
INTF flag  
(INTCON<1>)  
5
2
GIE bit  
(INTCON<7>)  
INSTRUCTION FLOW  
PC  
0004h  
PC  
PC+1  
PC+1  
0005h  
Instruction  
Inst (PC+1)  
Inst (0004h)  
Inst (PC)  
Inst (0005h)  
Inst (0004h)  
fetched  
Instruction  
executed  
Dummy Cycle  
Dummy Cycle  
Inst (PC)  
Inst (PC-1)  
Note  
1: INTF flag is sampled here (every Q1).  
2: Interrupt latency = 3-4 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 INTRC and EXTRC oscillator modes.  
4: For minimum width of INT pulse, refer to AC specs.  
5: INTF is enabled to be set anytime during the Q4-Q1 cycles.  
1999 Microchip Technology Inc.  
DS30561B-page 63  
PIC12C67X  
9.5.1  
TMR0 INTERRUPT  
9.6  
Context Saving During Interrupts  
During an interrupt, only the return PC value is saved  
on the stack. Typically, users may wish to save key reg-  
isters during an interrupt (i.e., W register and STATUS  
register). This will have to be implemented in software.  
An overflow (FFh 00h) in the TMR0 register will set  
flag bit T0IF (INTCON<2>). The interrupt can be  
enabled/disabled by setting/clearing enable bit T0IE  
(INTCON<5>) (Section 7.0). The flag bit T0IF  
(INTCON<2>) will be set, regardless of the state of the  
enable bits. If used, this flag must be cleared in software.  
Example 9-1 shows the storing and restoring of the  
STATUS and W registers. The register, W_TEMP, must  
be defined in both banks and must be defined at the  
same offset from the bank base address (i.e., if  
W_TEMP is defined at 0x20 in bank 0, it must also be  
defined at 0xA0 in bank 1).  
9.5.2  
INT INTERRUPT  
External interrupt on GP2/INT pin is edge triggered;  
either rising if bit INTEDG (OPTION<6>) is set, or fall-  
ing, if the INTEDG bit is clear. When a valid edge  
appears on the GP2/INT pin, flag bit INTF  
(INTCON<1>) is set. This interrupt can be disabled by  
clearing enable bit INTE (INTCON<4>). Flag bit INTF  
must be cleared in software in the interrupt service rou-  
tine before re-enabling this interrupt. The INT interrupt  
can wake-up the processor from SLEEP, if bit INTE was  
set prior to going into SLEEP. The status of global inter-  
rupt enable bit GIE decides whether or not the proces-  
sor branches to the interrupt vector following wake-up.  
See Section 9.8 for details on SLEEP mode.  
Example 9-2 shows the saving and restoring of STA-  
TUS and W using RAM locations 0x70 - 0x7F.  
W_TEMP is defined at 0x70 and STATUS_TEMP is  
defined at 0x71.  
The example:  
a) Stores the W register.  
b) Stores the STATUS register in bank 0.  
c) Executes the ISR code.  
d) Restores the STATUS register (and bank select  
bit).  
e) Restores the W register.  
f) Returns from interrupt.  
9.5.3  
GPIO INTCON CHANGE  
An input change on GP3, GP1 or GP0 sets flag bit GPIF  
(INTCON<0>). The interrupt can be enabled/disabled by  
setting/clearing enable bit GPIE (INTCON<3>)  
(Section 5.1) . This flag bit GPIF (INTCON<0>) will be  
set, regardless of the state of the enable bits. If used, this  
flag must be cleared in software.  
EXAMPLE 9-1: SAVING STATUS AND W REGISTERS USING GENERAL PURPOSE RAM  
(0x20 - 0x6F)  
MOVWF  
SWAPF  
BCF  
MOVWF  
:
W_TEMP  
;Copy W to TEMP register, could be bank one or zero  
;Swap status to be saved into W  
;Change to bank zero, regardless of current bank  
;Save status to bank zero STATUS_TEMP register  
STATUS,W  
STATUS,RP0  
STATUS_TEMP  
:(ISR)  
:
SWAPF  
STATUS_TEMP,W  
;Swap STATUS_TEMP register into W  
;(sets bank to original state)  
;Move W into STATUS register  
;Swap W_TEMP  
;Swap W_TEMP into W  
;Return from interrupt  
MOVWF  
SWAPF  
SWAPF  
RETFIE  
STATUS  
W_TEMP,F  
W_TEMP,W  
EXAMPLE 9-2: SAVING STATUS AND W REGISTERS USING SHARED RAM (0x70 - 0x7F)  
MOVWF  
MOVF  
MOVWF  
:
W_TEMP  
STATUS,W  
STATUS_TEMP  
;Copy W to TEMP register (bank independent)  
;Move STATUS register into W  
;Save contents of STATUS register  
:(ISR)  
:
MOVF  
MOVWF  
SWAPF  
SWAPF  
RETFIE  
STATUS_TEMP,W  
STATUS  
W_TEMP,F  
W_TEMP,W  
;Retrieve copy of STATUS register  
;Restore pre-isr STATUS register contents  
;
;Restore pre-isr W register contents  
;Return from interrupt  
DS30561B-page 64  
1999 Microchip Technology Inc.  
PIC12C67X  
The CLRWDT and SLEEP instructions clear the WDT  
and the postscaler, if assigned to the WDT, and prevent  
it from timing out early and generating a premature  
device RESET condition.  
9.7  
Watchdog Timer (WDT)  
The Watchdog Timer is a free running, on-chip RC  
oscillator, which does not require any external compo-  
nents. This RC oscillator is separate from the RC oscil-  
lator of the OSC1/CLKIN pin. That means that the WDT  
will run, even if the clock on the OSC1/CLKIN and  
OSC2/CLKOUT pins of the device has been stopped,  
for example, by execution of a SLEEPinstruction. Dur-  
ing normal operation, a WDT time-out generates a  
device RESET (Watchdog Timer Reset). If the device is  
in SLEEP mode, a WDT time-out causes the device to  
wake-up and continue with normal operation (Watch-  
dog Timer Wake-up). The WDT can be permanently  
disabled by clearing configuration bit WDTE  
(Section 9.1).  
The TO bit in the STATUS register will be cleared upon  
a Watchdog Timer time-out.  
9.7.2  
WDT PROGRAMMING CONSIDERATIONS  
It should also be taken into account that under worst  
case conditions (VDD = Min., Temperature = Max., and  
max. WDT prescaler), it may take several seconds  
before a WDT time-out occurs.  
Note: When the prescaler is assigned to the  
WDT, always execute a CLRWDTinstruction  
before changing the prescale value, other-  
wise a WDT reset may occur.  
9.7.1  
WDT PERIOD  
See Example 7-1 and Example 7-2 for changing pres-  
caler between WDT and Timer0.  
The WDT has a nominal time-out period of 18 ms (with  
no prescaler). The time-out periods vary with tempera-  
DD  
ture, V and process variations from part to part (see  
DC specs). If longer time-out periods are desired, a  
prescaler with a division ratio of up to 1:128 can be  
assigned to the WDT under software control by writing  
to the OPTION register. Thus, time-out periods up to  
2.3 seconds can be realized.  
FIGURE 9-15: WATCHDOG TIMER BLOCK DIAGRAM  
From TMR0 Clock Source  
(Figure 7-5)  
0
Postscaler  
8
M
1
U
WDT Timer  
X
8 - to - 1 MUX  
PS<2:0>  
PSA  
WDT  
Enable Bit  
To TMR0 (Figure 7-5)  
0
1
MUX  
PSA  
WDT  
Time-out  
Note: PSA and PS<2:0> are bits in the OPTION register.  
TABLE 9-8:  
Address  
SUMMARY OF WATCHDOG TIMER REGISTERS  
Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
PWRTE WDTE FOSC2 FOSC1 FOSC0  
T0SE PSA PS2 PS1 PS0  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
Config. bits(1)  
OPTION  
2007h  
81h  
MCLRE  
GPPU  
CP1  
CP0  
INTEDG T0CS  
Legend: Shaded cells are not used by the Watchdog Timer.  
Note 1: See Register 9-1 for operation of these bits. Not all CP0 and CP1 bits are shown.  
1999 Microchip Technology Inc.  
DS30561B-page 65  
PIC12C67X  
Other peripherals can not generate interrupts since  
during SLEEP, no on-chip Q clocks are present.  
9.8  
Power-down Mode (SLEEP)  
Power-down mode is entered by executing a SLEEP  
When the SLEEPinstruction is being executed, the next  
instruction (PC + 1) is pre-fetched. For the device to  
wake-up through an interrupt event, the corresponding  
interrupt enable bit must be set (enabled). Wake-up is  
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 SLEEP instruction and 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.  
instruction.  
If enabled, the Watchdog Timer will be cleared but  
keeps running, the PD bit (STATUS<3>) is cleared, the  
TO (STATUS<4>) bit is set, and the oscillator driver is  
turned off. The I/O ports maintain the status they had,  
before the SLEEP instruction was executed (driving  
high, low or hi-impedance).  
For lowest current consumption in this mode, place all  
I/O pins at either VDD or VSS, ensure no external cir-  
cuitry is drawing current from the I/O pin, power-down  
the A/D, and disable external clocks. Pull all I/O pins  
that are hi-impedance inputs, high or low externally, to  
avoid switching currents caused by floating inputs. The  
T0CKI input, if enabled, should also be at VDD or VSS  
for lowest current consumption. The contribution from  
on-chip pull-ups on GPIO should be considered.  
9.8.2  
WAKE-UP USING INTERRUPTS  
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:  
The MCLR pin, if enabled, must be at a logic high level  
(VIHMC).  
• If the interrupt occurs before the the execution of  
a SLEEPinstruction, the SLEEPinstruction will  
complete as a NOP. Therefore, the WDT and WDT  
postscaler will not be cleared, the TO bit will not  
be set and PD bits will not be cleared.  
9.8.1  
WAKE-UP FROM SLEEP  
The device can wake-up from SLEEP through one of  
the following events:  
• If the interrupt occurs during or after the execu-  
tion of a SLEEPinstruction, the device will imme-  
diately wake-up from sleep . The SLEEP  
instruction will be completely executed before the  
wake-up. Therefore, the WDT and WDT  
postscaler will be cleared, the TO bit will be set  
and the PD bit will be cleared.  
1. External reset input on MCLR pin.  
2. Watchdog Timer Wake-up (if WDT was  
enabled).  
3. GP2/INT interrupt, interrupt GPIO port change  
or some Peripheral Interrupts.  
External MCLR Reset will cause a device reset. All  
other events are considered a continuation of program  
execution and cause a "wake-up". The TO and PD bits  
in the STATUS register can be used to determine the  
cause of device reset. The PD bit, which is set on  
power-up, is cleared when SLEEPis invoked. The TO  
bit is cleared if a WDT time-out occurred (and caused  
wake-up).  
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.  
To ensure that the WDT is cleared, a CLRWDTinstruc-  
tion should be executed before a SLEEPinstruction.  
The following peripheral interrupt can wake the device  
from SLEEP:  
1. A/D conversion (when A/D clock source is RC).  
DS30561B-page 66  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 9-16: 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  
TOST(2)  
CLKOUT(4)  
GPIO pin  
GPIF flag  
(INTCON<0>)  
Interrupt Latency  
(Note 3)  
GIE bit  
(INTCON<7>)  
Processor in  
SLEEP  
INSTRUCTION FLOW  
PC  
PC  
PC+1  
PC+2  
PC+2  
PC + 2  
0004h  
0005h  
Instruction  
Inst(0004h)  
Inst(PC + 1)  
Inst(PC + 2)  
Inst(0005h)  
Inst(PC) = SLEEP  
Inst(PC - 1)  
fetched  
Instruction  
executed  
Dummy cycle  
Dummy cycle  
SLEEP  
Inst(PC + 1)  
Inst(0004h)  
Note 1: XT, HS or LP oscillator mode assumed.  
2: TOST = 1024TOSC (drawing not to scale) This delay will not be there for INTRC and EXTRC osc mode.  
3: GIE = ’1’ assumed. In this case after wake- up, the processor jumps to the interrupt routine. If GIE = ’0’, execution will  
continue in-line.  
4: CLKOUT is not available in XT, HS or LP osc modes, but shown here for timing reference.  
After reset, and if the device is placed into program-  
ming/verify mode, the program counter (PC) is at loca-  
tion 00h. A 6-bit command is then supplied to the  
device. Depending on the command, 14-bits of pro-  
gram data are then supplied to or from the device,  
depending if the command was a load or a read. For  
complete details of serial programming, please refer to  
the PIC12C67X Programming Specifications.  
9.9  
Program Verification/Code Protection  
If the code protection bit(s) have not been pro-  
grammed, the on-chip program memory can be read  
out for verification purposes.  
Note: Microchip does not recommend code pro-  
tecting windowed devices.  
9.10  
ID Locations  
FIGURE 9-17: TYPICAL IN-CIRCUIT SERIAL  
PROGRAMMING  
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 read-  
able and writable during program/verify. It is recom-  
mended that only the 4 least significant bits of the ID  
location are used.  
CONNECTION  
To Normal  
Connections  
External  
Connector  
Signals  
PIC12C67X  
9.11  
In-Circuit Serial Programming  
+5V  
0V  
VDD  
PIC12C67X microcontrollers can be serially pro-  
grammed while in the end application circuit. This is  
simply done with two lines for clock and data, and three  
other lines for power, ground and the programming volt-  
age. 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.  
VSS  
VPP  
MCLR/VPP  
GP1  
GP0  
CLK  
Data I/O  
VDD  
To Normal  
Connections  
The device is placed into a program/verify mode by  
holding the GP1 and GP0 pins low, while raising the  
MCLR (VPP) pin from VIL to VIHH (see programming  
specification). GP1 (clock) becomes the programming  
clock and GP0 (data) becomes the programming data.  
Both GP0 and GP1 are Schmitt Trigger inputs in this  
mode.  
1999 Microchip Technology Inc.  
DS30561B-page 67  
PIC12C67X  
NOTES:  
DS30561B-page 68  
1999 Microchip Technology Inc.  
PIC12C67X  
The instruction set is highly orthogonal and is grouped  
into three basic categories:  
10.0 INSTRUCTION SET SUMMARY  
Each PIC12C67X 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 PIC12C67X instruc-  
tion set summary in Table 10-2 lists byte-oriented, bit-  
oriented, and literal and control operations. Table 10-  
1 shows the opcode field descriptions.  
Byte-oriented operations  
Bit-oriented operations  
Literal and control operations  
All instructions are executed within one single instruc-  
tion cycle, unless a conditional test is true or the pro-  
gram counter is changed as a result of an instruction.  
In this case, the execution takes two instruction cycles  
with the second cycle executed as a NOP. One instruc-  
tion cycle consists of four oscillator periods. Thus, for  
an oscillator frequency of 4 MHz, the normal instruction  
execution time is 1 µs. If a conditional test is true or the  
program counter is changed as a result of an instruc-  
tion, the instruction execution time is 2 µs.  
For byte-oriented instructions, ’f’ represents a file reg-  
ister designator and ’d’ represents a destination desig-  
nator. The file register designator specifies which file  
register is to be used by the instruction.  
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.  
Table 10-2 lists the instructions recognized by the  
MPASM assembler.  
For bit-oriented instructions, ’b’ represents a bit field  
designator which selects the number of the bit affected  
by the operation, while ’f’ represents the number of the  
file in which the bit is located.  
Figure 10-1 shows the three general formats that the  
instructions can have.  
Note: To maintain upward compatibility with  
future PIC12C67X products, do not use the  
OPTIONand TRISinstructions.  
For literal and control operations, ’k’ represents an  
eight or eleven bit constant or literal value.  
All examples use the following format to represent a  
hexadecimal number:  
TABLE 10-1: OPCODE FIELD  
DESCRIPTIONS  
0xhh  
Field  
Description  
where h signifies a hexadecimal digit.  
f
W
b
k
x
Register file address (0x00 to 0x7F)  
Working register (accumulator)  
FIGURE 10-1: GENERAL FORMAT FOR  
INSTRUCTIONS  
Bit address within an 8-bit file register  
Literal field, constant data or label  
Byte-oriented file register operations  
13  
8
7
6
0
0
Don’t care location (= 0 or 1)  
OPCODE  
d
f (FILE #)  
The assembler will generate code with x = 0. It is the  
recommended form of use for compatibility with all  
Microchip software tools.  
d = 0 for destination W  
d = 1 for destination f  
f = 7-bit file register address  
d
Destination select; d = 0: store result in W,  
d = 1: store result in file register f.  
Default is d = 1  
Bit-oriented file register operations  
13 10 9  
7 6  
label Label name  
TOS Top of Stack  
PC Program Counter  
OPCODE  
b (BIT #)  
f (FILE #)  
b = 3-bit bit address  
f = 7-bit file register address  
PCLATH  
Program Counter High Latch  
GIE Global Interrupt Enable bit  
WDT Watchdog Timer/Counter  
TO Time-out bit  
Literal and control operations  
General  
13  
8
7
0
0
OPCODE  
k (literal)  
PD Power-down bit  
dest Destination either the W register or the specified  
k = 8-bit immediate value  
CALLand GOTOinstructions only  
13 11 10  
OPCODE  
k = 11-bit immediate value  
register file location  
[ ] Options  
Contents  
( )  
k (literal)  
Assigned to  
Register bit field  
In the set of  
< >  
User defined term (font is courier)  
italics  
1999 Microchip Technology Inc.  
DS30561B-page 69  
PIC12C67X  
10.1.3 PCL AS SOURCE OR DESTINATION  
10.1  
Special Function Registers as  
Source/Destination  
Read, write or read-modify-write on PCL may have the  
following results:  
The PIC12C67X’s orthogonal instruction set allows  
read and write of all file registers, including special  
function registers. There are some special situations  
the user should be aware of:  
Read PC:  
PCL dest  
Write PCL:  
PCLATH PCH;  
8-bit destination value PCL  
10.1.1 STATUS AS DESTINATION  
Read-Modify-Write: PCLALU operand  
PCLATH PCH;  
If an instruction writes to STATUS, the Z, C and DC bits  
may be set or cleared as a result of the instruction and  
overwrite the original data bits written. For example,  
executing CLRF STATUS will clear register STATUS,  
and then set the Z bit leaving 0000 0100bin the reg-  
ister.  
8-bit result PCL  
Where PCH = program counter high byte (not an  
addressable register), PCLATH = Program counter  
high holding latch, dest = destination, WREG or f.  
10.1.4 BIT MANIPULATION  
10.1.2 TRIS AS DESTINATION  
All bit manipulation instructions are done by first read-  
ing the entire register, operating on the selected bit and  
writing the result back (read-modify-write). The user  
should keep this in mind when operating on special  
function registers, such as ports.  
Bit 3 of the TRIS register always reads as a '1' since  
GP3 is an input only pin. This fact can affect some read-  
modify-write operations on the TRIS register.  
DS30561B-page 70  
1999 Microchip Technology Inc.  
PIC12C67X  
TABLE 10-2: INSTRUCTION SET SUMMARY  
Mnemonic,  
Operands  
Description  
Cycles  
14-Bit Opcode  
Status  
Affected  
Notes  
MSb  
LSb  
BYTE-ORIENTED FILE REGISTER OPERATIONS  
ADDWF  
ANDWF  
CLRF  
CLRW  
COMF  
DECF  
f, d Add W and f  
f, d AND W with f  
1
1
1
1
1
1
1(2)  
1
1(2)  
1
1
1
1
1
1
1
1
1
00  
00  
00  
00  
00  
00  
00  
00  
00  
00  
00  
00  
00  
00  
00  
00  
00  
00  
0111 dfff ffff C,DC,Z  
1,2  
1,2  
2
0101 dfff ffff  
0001 lfff ffff  
0001 0000 0011  
1001 dfff ffff  
0011 dfff ffff  
1011 dfff ffff  
1010 dfff ffff  
1111 dfff ffff  
0100 dfff ffff  
1000 dfff ffff  
0000 lfff ffff  
0000 0xx0 0000  
1101 dfff ffff  
1100 dfff ffff  
Z
Z
Z
Z
Z
f
-
Clear f  
Clear W  
f, d Complement f  
f, d Decrement f  
f, d Decrement f, Skip if 0  
f, d Increment f  
f, d Increment f, Skip if 0  
f, d Inclusive OR W with f  
f, d Move f  
1,2  
1,2  
1,2,3  
1,2  
1,2,3  
1,2  
DECFSZ  
INCF  
Z
INCFSZ  
IORWF  
MOVF  
MOVWF  
NOP  
RLF  
RRF  
SUBWF  
SWAPF  
XORWF  
Z
Z
1,2  
f
-
Move W to f  
No Operation  
f, d Rotate Left f through Carry  
f, d Rotate Right f through Carry  
f, d Subtract W from f  
f, d Swap nibbles in f  
f, d Exclusive OR W with f  
C
C
1,2  
1,2  
1,2  
1,2  
1,2  
0010 dfff ffff C,DC,Z  
1110 dfff ffff  
0110 dfff ffff Z  
BIT-ORIENTED FILE REGISTER OPERATIONS  
BCF  
BSF  
BTFSC  
BTFSS  
f, b Bit Clear f  
f, b Bit Set f  
f, b Bit Test f, Skip if Clear  
f, b Bit Test f, Skip if Set  
1
1
01  
01  
00bb bfff ffff  
01bb bfff ffff  
10bb bfff ffff  
11bb bfff ffff  
1,2  
1,2  
3
1 (2) 01  
1 (2) 01  
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  
11  
10  
00  
10  
11  
11  
00  
11  
00  
00  
11  
11  
111x kkkk kkkk C,DC,Z  
1001 kkkk kkkk  
0kkk kkkk kkkk  
Z
0000 0110 0100 TO,PD  
1kkk kkkk kkkk  
Inclusive OR literal with W  
Move literal to W  
1000 kkkk kkkk  
00xx kkkk kkkk  
0000 0000 1001  
01xx kkkk kkkk  
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  
0000 0110 0011 TO,PD  
110x kkkk kkkk C,DC,Z  
1010 kkkk kkkk  
Z
Note 1: When an I/O register is modified as a function of itself ( i.e., MOVF PORTB, 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 Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is  
executed as a NOP.  
1999 Microchip Technology Inc.  
DS30561B-page 71  
PIC12C67X  
10.2  
Instruction Descriptions  
ADDLW  
Add Literal and W  
[ label ] ADDLW  
0 k 255  
ANDLW  
And Literal with W  
[ label ] ANDLW  
0 k 255  
Syntax:  
k
Syntax:  
k
Operands:  
Operation:  
Status Affected:  
Encoding:  
Description:  
Operands:  
Operation:  
Status Affected:  
Encoding:  
Description:  
(W) + k (W)  
C, DC, Z  
(W) .AND. (k) (W)  
Z
11  
111x  
kkkk  
kkkk  
11  
1001  
kkkk  
kkkk  
The contents of the W register are  
added to the eight bit literal ’k’ and  
the result is placed in the W regis-  
ter.  
The contents of W register are  
AND’ed with the eight bit literal 'k'.  
The result is placed in the W reg-  
ister.  
Words:  
Cycles:  
Example  
1
1
Words:  
Cycles:  
Example  
1
1
ADDLW  
0x15  
ANDLW  
0x5F  
Before Instruction  
Before Instruction  
W
=
0x10  
0x25  
W
=
0xA3  
0x03  
After Instruction  
After Instruction  
W
=
W
=
ADDWF  
Syntax:  
Add W and f  
ANDWF  
Syntax:  
AND W with f  
[ label ] ADDWF f,d  
[ label ] ANDWF f,d  
Operands:  
0 f 127  
Operands:  
0 f 127  
d
[0,1]  
d
[0,1]  
Operation:  
(W) + (f) (dest)  
Operation:  
(W) .AND. (f) (dest)  
Status Affected:  
Encoding:  
C, DC, Z  
Status Affected:  
Encoding:  
Z
00  
0111  
dfff  
ffff  
00  
0101  
dfff  
ffff  
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 reg-  
ister ’f’.  
Description:  
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'.  
Words:  
Cycles:  
Example  
1
1
Words:  
Cycles:  
Example  
1
1
ANDWF  
FSR,  
1
ADDWF  
FSR,  
0
Before Instruction  
Before Instruction  
W
=
0x17  
0xC2  
W
=
0x17  
0xC2  
FSR =  
FSR =  
After Instruction  
After Instruction  
W
=
0x17  
0x02  
W
=
0xD9  
0xC2  
FSR =  
FSR =  
DS30561B-page 72  
1999 Microchip Technology Inc.  
PIC12C67X  
BCF  
Bit Clear f  
BTFSC  
Bit Test, Skip if Clear  
Syntax:  
Operands:  
[ label ] BCF f,b  
Syntax:  
[ label ] BTFSC f,b  
0 f 127  
0 b 7  
Operands:  
0 f 127  
0 b 7  
Operation:  
Status Affected:  
Encoding:  
Description:  
Words:  
0 (f<b>)  
Operation:  
skip if (f<b>) = 0  
None  
None  
Status Affected:  
Encoding:  
01  
00bb  
bfff  
ffff  
01  
10bb  
bfff  
ffff  
Bit ’b’ in register ’f’ is cleared.  
Description:  
If bit ’b’ in register ’f’ is ’0’, then the  
next instruction is skipped.  
If bit ’b’ is ’0’, then the next instruc-  
tion fetched during the current  
instruction execution is discarded,  
and a NOPis executed instead,  
making this a 2 cycle instruction.  
1
1
Cycles:  
BCF  
FLAG_REG, 7  
Example  
Before Instruction  
FLAG_REG = 0xC7  
Words:  
Cycles:  
Example  
1
After Instruction  
1(2)  
FLAG_REG = 0x47  
HERE  
FALSE  
TRUE  
BTFSC  
GOTO  
FLAG,1  
PROCESS_CO  
DE  
Before Instruction  
PC  
=
address HERE  
After Instruction  
if FLAG<1> = 0,  
PC =  
address TRUE  
if FLAG<1>=1,  
PC =  
address FALSE  
BSF  
Bit Set f  
Syntax:  
Operands:  
[ label ] BSF f,b  
0 f 127  
0 b 7  
Operation:  
Status Affected:  
Encoding:  
Description:  
Words:  
1 (f<b>)  
None  
01  
01bb  
bfff  
ffff  
Bit ’b’ in register ’f’ is set.  
1
1
Cycles:  
BSF  
FLAG_REG,  
7
Example  
Before Instruction  
FLAG_REG = 0x0A  
After Instruction  
FLAG_REG = 0x8A  
1999 Microchip Technology Inc.  
DS30561B-page 73  
PIC12C67X  
CLRF  
Clear f  
BTFSS  
Bit Test f, Skip if Set  
Syntax:  
[ label ] CLRF  
0 f 127  
f
Syntax:  
[ label ] BTFSS f,b  
Operands:  
Operation:  
Operands:  
0 f 127  
0 b < 7  
00h (f)  
1 Z  
Operation:  
skip if (f<b>) = 1  
None  
Status Affected:  
Encoding:  
Z
Status Affected:  
Encoding:  
00  
0001  
1fff  
ffff  
01  
11bb  
bfff  
ffff  
Description:  
The contents of register ’f’ are  
cleared and the Z bit is set.  
Description:  
If bit ’b’ in register ’f’ is ’1’, then the  
next instruction is skipped.  
If bit ’b’ is ’1’, then the next instruc-  
tion fetched during the current  
instruction execution, is discarded  
and a NOPis executed instead,  
making this a 2 cycle instruction.  
Words:  
Cycles:  
Example  
1
1
CLRF  
FLAG_REG  
Before Instruction  
FLAG_REG  
After Instruction  
FLAG_REG  
Words:  
Cycles:  
Example  
1
=
0x5A  
1(2)  
=
=
0x00  
1
HERE  
FALSE  
TRUE  
BTFSS  
GOTO  
FLAG,1  
PROCESS_CO  
DE  
Z
Before Instruction  
PC  
=
address HERE  
After Instruction  
if FLAG<1> = 0,  
PC =  
address FALSE  
if FLAG<1> = 1,  
PC =  
address TRUE  
CLRW  
Clear W  
CALL  
Call Subroutine  
[ label ] CALL k  
0 k 2047  
Syntax:  
[ label ] CLRW  
None  
Syntax:  
Operands:  
Operation:  
Operands:  
Operation:  
00h (W)  
1 Z  
(PC)+ 1TOS,  
k PC<10:0>,  
(PCLATH<4:3>) PC<12:11>  
Status Affected:  
Encoding:  
Z
00  
0001  
0000  
0011  
Status Affected:  
Encoding:  
None  
Description:  
W register is cleared. Zero bit (Z)  
is set.  
10  
0kkk  
kkkk  
kkkk  
Description:  
Call Subroutine. First, return  
Words:  
Cycles:  
Example  
1
address (PC+1) is pushed onto  
the stack. The eleven bit immedi-  
ate address is loaded into PC bits  
<10:0>. The upper bits of the PC  
are loaded from PCLATH. CALLis  
a two cycle instruction.  
1
CLRW  
Before Instruction  
W
=
0x5A  
After Instruction  
Words:  
Cycles:  
Example  
1
2
W
Z
=
=
0x00  
1
HERE  
CALL  
THER  
E
Before Instruction  
PC  
=
Address HERE  
After Instruction  
PC  
= Address THERE  
TOS = Address HERE+1  
DS30561B-page 74  
1999 Microchip Technology Inc.  
PIC12C67X  
CLRWDT  
Syntax:  
Clear Watchdog Timer  
[ label ] CLRWDT  
None  
DECF  
Decrement f  
Syntax:  
Operands:  
[ label ] DECF f,d  
Operands:  
Operation:  
0 f 127  
d
[0,1]  
00h WDT  
0 WDT prescaler,  
1 TO  
Operation:  
(f) - 1 (dest)  
Status Affected:  
Encoding:  
Z
1 PD  
00  
0011  
dfff  
ffff  
Status Affected:  
Encoding:  
TO, PD  
Description:  
Decrement register ’f’. If ’d’ is 0,  
the result is stored in the W regis-  
ter. If ’d’ is 1, the result is stored  
back in register ’f’.  
00  
0000  
0110  
0100  
Description:  
CLRWDTinstruction resets the  
Watchdog Timer. It also resets the  
prescaler of the WDT. Status bits  
TO and PD are set.  
Words:  
Cycles:  
Example  
1
1
Words:  
Cycles:  
Example  
1
DECF  
CNT,  
1
1
Before Instruction  
CNT  
CLRWDT  
=
=
0x01  
0
Before Instruction  
Z
WDT counter  
=
=
?
After Instruction  
CNT  
After Instruction  
=
=
0x00  
1
WDT counter  
0x00  
Z
WDT prescaler=  
0
1
1
TO  
PD  
=
=
COMF  
Complement f  
[ label ] COMF f,d  
0 f 127  
DECFSZ  
Syntax:  
Decrement f, Skip if 0  
[ label ] DECFSZ f,d  
0 f 127  
Syntax:  
Operands:  
Operands:  
d
[0,1]  
d
[0,1]  
Operation:  
(f) (dest)  
Operation:  
(f) - 1 (dest); skip if result = 0  
Status Affected:  
Encoding:  
Z
Status Affected:  
Encoding:  
None  
00  
1001  
dfff  
ffff  
00  
1011  
dfff  
ffff  
Description:  
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:  
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 reg-  
ister ’f’.  
If the result is 0, the next instruc-  
tion, which is already fetched, is  
discarded. A NOPis executed  
instead making it a two cycle  
instruction.  
Words:  
Cycles:  
Example  
1
1
COMF  
REG1,0  
Before Instruction  
REG1  
=
0x13  
Words:  
Cycles:  
Example  
1
After Instruction  
REG1  
=
=
0x13  
0xEC  
1(2)  
W
HERE  
DECFSZ  
GOTO  
CNT, 1  
LOOP  
CONTINUE •  
Before Instruction  
PC  
=
address HERE  
After Instruction  
CNT  
if CNT =  
PC  
if CNT ≠  
PC  
=
CNT - 1  
0,  
address CONTINUE  
0,  
=
=
address HERE+1  
1999 Microchip Technology Inc.  
DS30561B-page 75  
PIC12C67X  
GOTO  
Unconditional Branch  
INCFSZ  
Syntax:  
Increment f, Skip if 0  
[ label ] INCFSZ f,d  
0 f 127  
Syntax:  
[ label ] GOTO k  
Operands:  
Operation:  
0 k 2047  
Operands:  
d
[0,1]  
k PC<10:0>  
PCLATH<4:3> PC<12:11>  
Operation:  
(f) + 1 (dest), skip if result = 0  
Status Affected:  
Encoding:  
None  
Status Affected:  
Encoding:  
None  
10  
1kkk  
kkkk  
kkkk  
00  
1111  
dfff  
ffff  
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.  
Description:  
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 reg-  
ister ’f’.  
If the result is 0, the next instruc-  
tion, which is already fetched, is  
discarded. A NOPis executed  
instead making it a two cycle  
instruction.  
Words:  
Cycles:  
Example  
1
2
GOTO THERE  
Words:  
Cycles:  
Example  
1
After Instruction  
1(2)  
PC  
=
Address THERE  
HERE  
INCFSZ  
GOTO  
CNT,  
LOOP  
1
CONTINUE •  
Before Instruction  
PC  
=
address HERE  
After Instruction  
CNT  
if CNT=  
=
CNT + 1  
0,  
PC  
if CNT≠  
=
address CONTINUE  
0,  
PC  
=
address HERE +1  
INCF  
Increment f  
IORLW  
Inclusive OR Literal with W  
[ label ] IORLW k  
0 k 255  
Syntax:  
Operands:  
[ label ] INCF f,d  
Syntax:  
0 f 127  
d
[0,1]  
Operands:  
Operation:  
Status Affected:  
Encoding:  
Description:  
Operation:  
(f) + 1 (dest)  
(W) .OR. k (W)  
Z
Status Affected:  
Encoding:  
Z
00  
1010  
dfff  
ffff  
11  
1000  
kkkk  
kkkk  
Description:  
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 reg-  
ister ’f’.  
The contents of the W register are  
OR’ed with the eight bit literal 'k'.  
The result is placed in the W reg-  
ister.  
Words:  
Cycles:  
Example  
1
1
Words:  
Cycles:  
Example  
1
1
IORLW  
0x35  
INCF  
CNT,  
1
Before Instruction  
Before Instruction  
CNT  
W
=
0x9A  
=
=
0xFF  
0
After Instruction  
Z
W
Z
=
=
0xBF  
1
After Instruction  
CNT  
=
=
0x00  
1
Z
DS30561B-page 76  
1999 Microchip Technology Inc.  
PIC12C67X  
IORWF  
Inclusive OR W with f  
[ label ] IORWF f,d  
0 f 127  
MOVF  
Move f  
Syntax:  
Syntax:  
Operands:  
[ label ] MOVF f,d  
Operands:  
0 f 127  
d
[0,1]  
d
[0,1]  
Operation:  
(W) .OR. (f) (dest)  
Operation:  
(f) (dest)  
Status Affected:  
Encoding:  
Z
Status Affected:  
Encoding:  
Z
00  
0100  
dfff  
ffff  
00  
1000  
dfff  
ffff  
Description:  
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 regis-  
ter ’f’.  
Description:  
The contents of register f are  
moved to a destination dependant  
upon the status of d. If d = 0, des-  
tination is W register. If d = 1, the  
destination is file register f itself.  
d = 1 is useful to test a file register  
since status flag Z is affected.  
Words:  
Cycles:  
Example  
1
1
Words:  
Cycles:  
Example  
1
1
IORWF  
RESULT, 0  
Before Instruction  
MOVF  
FSR,  
0
RESULT =  
0x13  
0x91  
After Instruction  
W
=
W = value in FSR register  
= 1  
After Instruction  
Z
RESULT =  
0x13  
0x93  
1
W
Z
=
=
MOVWF  
Move W to f  
[ label ] MOVWF  
0 f 127  
(W) (f)  
MOVLW  
Move Literal to W  
[ label ] MOVLW k  
0 k 255  
Syntax:  
f
Syntax:  
Operands:  
Operation:  
Status Affected:  
Encoding:  
Description:  
Operands:  
Operation:  
Status Affected:  
Encoding:  
Description:  
k (W)  
None  
None  
00  
0000  
1fff  
ffff  
11  
00xx  
kkkk  
kkkk  
Move data from W register to reg-  
ister 'f'.  
The eight bit literal ’k’ is loaded  
into W register. The don’t cares  
will assemble as 0’s.  
Words:  
Cycles:  
Example  
1
1
Words:  
Cycles:  
Example  
1
1
MOVWF  
OPTION  
Before Instruction  
MOVLW  
0x5A  
OPTION =  
0xFF  
0x4F  
W
=
After Instruction  
After Instruction  
W
=
0x5A  
OPTION =  
0x4F  
0x4F  
W
=
1999 Microchip Technology Inc.  
DS30561B-page 77  
PIC12C67X  
NOP  
No Operation  
RETFIE  
Return from Interrupt  
[ label ] RETFIE  
None  
Syntax:  
[ label ] NOP  
None  
Syntax:  
Operands:  
Operation:  
Status Affected:  
Encoding:  
Description:  
Words:  
Operands:  
Operation:  
No operation  
None  
TOS PC,  
1 GIE  
Status Affected:  
Encoding:  
None  
00  
0000  
0xx0  
0000  
00  
0000  
0000  
1001  
No operation.  
Description:  
Return from Interrupt. Stack is  
POPed and Top of Stack (TOS) is  
loaded in the PC. Interrupts are  
enabled by setting Global Inter-  
rupt Enable bit, GIE  
(INTCON<7>). This is a two cycle  
instruction.  
1
Cycles:  
1
NOP  
Example  
Words:  
Cycles:  
Example  
1
2
RETFIE  
After Interrupt  
PC  
=
TOS  
1
GIE =  
OPTION  
Syntax:  
Load Option Register  
[ label ] OPTION  
None  
RETLW  
Return with Literal in W  
[ label ] RETLW k  
0 k 255  
Syntax:  
Operands:  
Operation:  
Status Affected:  
Encoding:  
Description:  
Operands:  
Operation:  
(W) OPTION  
None  
k (W);  
TOS PC  
Status Affected:  
Encoding:  
None  
00  
0000  
0110  
0010  
11  
01xx  
kkkk  
kkkk  
The contents of the W register are  
loaded in the OPTION register.  
This instruction is supported for  
code compatibility with PIC16C5X  
products. Since OPTION is a read-  
able/writable register, the user can  
directly address it.  
Description:  
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.  
Words:  
Cycles:  
Example  
1
2
Words:  
Cycles:  
Example  
1
1
CALL TABLE;W contains  
table  
To maintain upward compatibility  
with future PIC12C67X products,  
do not use this instruction.  
;offset value  
TABLE  
;W now has table value  
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  
DS30561B-page 78  
1999 Microchip Technology Inc.  
PIC12C67X  
RETURN  
Return from Subroutine  
[ label ] RETURN  
None  
RRF  
Rotate Right f through Carry  
[ label ] RRF f,d  
0 f 127  
Syntax:  
Syntax:  
Operands:  
Operands:  
Operation:  
Status Affected:  
Encoding:  
Description:  
d
[0,1]  
TOS PC  
Operation:  
See description below  
C
None  
Status Affected:  
Encoding:  
00  
0000  
0000  
1000  
00  
1100  
dfff  
ffff  
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.  
Description:  
The contents of register ’f’ are  
rotated one bit to the right through  
the Carry Flag. If ’d’ is 0, the result  
is placed in the W register. If ’d’ is  
1, the result is placed back in reg-  
ister ’f’.  
Words:  
Cycles:  
Example  
1
2
C
Register f  
RETURN  
Words:  
Cycles:  
Example  
1
1
After Interrupt  
PC  
=
TOS  
RRF  
REG1,  
0
Before Instruction  
REG1  
=
=
1110 0110  
0
C
After Instruction  
REG1  
=
=
=
1110 0110  
0111 0011  
0
W
C
RLF  
Rotate Left f through Carry  
SLEEP  
Syntax:  
Operands:  
[ label ]  
RLF f,d  
Syntax:  
[ label ]  
SLEEP  
0 f 127  
Operands:  
Operation:  
None  
d
[0,1]  
00h WDT,  
0 WDT prescaler,  
1 TO,  
Operation:  
See description below  
C
Status Affected:  
Encoding:  
0 PD  
00  
1101  
dfff  
ffff  
Status Affected:  
Encoding:  
TO, PD  
Description:  
The contents of register ’f’ are  
rotated one bit to the left through  
the Carry Flag. If ’d’ is 0, the result  
is placed in the W register. If ’d’ is  
1, the result is stored back in reg-  
ister ’f’.  
00  
0000  
0110  
0011  
Description:  
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:  
Cycles:  
Example  
1
1
Words:  
1
Cycles:  
Example:  
1
RLF  
REG1,0  
SLEEP  
Before Instruction  
REG1  
=
=
1110 0110  
0
C
After Instruction  
REG1  
=
=
=
1110 0110  
1100 1100  
1
W
C
1999 Microchip Technology Inc.  
DS30561B-page 79  
PIC12C67X  
SUBLW  
Subtract W from Literal  
SUBWF  
Subtract W from f  
Syntax:  
[ label ]  
Syntax:  
[ label ]  
SUBLW k  
SUBWF f,d  
Operands:  
Operation:  
0 k 255  
Operands:  
Operation:  
0 f 127  
[0,1]  
d
k - (W) → (W)  
(f) - (W) → (dest)  
Status  
Affected:  
C, DC, Z  
Status  
Affected:  
C, DC, Z  
Encoding:  
11  
110x  
kkkk  
kkkk  
Encoding:  
00  
0010  
dfff  
ffff  
Description:  
The W register is subtracted (2’s  
complement method) from 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 regis-  
ter 'f'.  
Words:  
1
1
Cycles:  
Words:  
1
1
Example 1:  
SUBLW  
0x02  
Cycles:  
Before Instruction  
Example 1:  
SUBWF  
REG1,1  
W
C
=
=
1
?
Before Instruction  
REG1  
W
C
=
=
=
3
2
?
After Instruction  
W
C
=
=
1
1; result is positive  
After Instruction  
Example 2:  
Example 3:  
Before Instruction  
REG1  
W
C
=
=
=
1
2
W
C
=
=
2
?
1; result is positive  
Example 2:  
Before Instruction  
After Instruction  
REG1  
W
C
=
=
=
2
2
?
W
C
=
=
0
1; result is zero  
Before Instruction  
After Instruction  
W
C
=
=
3
?
REG1  
W
C
=
=
=
0
2
After Instruction  
1; result is zero  
W
C
=
=
0xFF  
0; result is nega-  
Example 3:  
Before Instruction  
REG1  
W
C
=
=
=
1
2
?
tive  
After Instruction  
REG1  
W
C
=
=
=
0xFF  
2
0; result is negative  
DS30561B-page 80  
1999 Microchip Technology Inc.  
PIC12C67X  
SWAPF  
Syntax:  
Swap Nibbles in f  
[ label ] SWAPF f,d  
0 f 127  
XORLW  
Exclusive OR Literal with W  
Syntax:  
[ label ]  
XORLW k  
Operands:  
Operands:  
0 k 255  
d
[0,1]  
Operation:  
(W) .XOR. k → (W)  
Operation:  
(f<3:0>) (dest<7:4>),  
(f<7:4>) (dest<3:0>)  
Status Affected:  
Encoding:  
Z
Status Affected:  
Encoding:  
None  
11  
1010 kkkk kkkk  
00  
1110  
dfff  
ffff  
Description:  
The contents of the W register  
are XOR’ed with the eight bit lit-  
eral 'k'. The result is placed in the  
W register.  
Description:  
The upper and lower nibbles of  
register ’f’ are exchanged. If ’d’ is  
0, the result is placed in W regis-  
ter. If ’d’ is 1, the result is placed in  
register ’f’.  
Words:  
1
1
Cycles:  
Example:  
Words:  
Cycles:  
Example  
1
1
XORLW  
0xAF  
Before Instruction  
SWAPF  
REG,  
0
W
=
0xB5  
0x1A  
Before Instruction  
REG1  
After Instruction  
=
0xA5  
W
=
After Instruction  
REG1  
W
=
=
0xA5  
0x5A  
XORWF  
Syntax:  
Exclusive OR W with f  
[ label ] XORWF f,d  
0 f 127  
TRIS  
Load TRIS Register  
Syntax:  
[ label ] TRIS  
f
Operands:  
Operands:  
Operation:  
Status Affected:  
Encoding:  
Description:  
5 f 7  
d
[0,1]  
(W) TRIS register f;  
Operation:  
(W) .XOR. (f) → (dest)  
None  
Status Affected:  
Encoding:  
Z
00  
0000 0110  
0fff  
00  
0110  
dfff  
ffff  
The instruction is supported for  
code compatibility with the  
PIC16C5X products. Since TRIS  
registers are readable and writ-  
able, the user can directly address  
them.  
Description:  
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'.  
Words:  
Cycles:  
Example  
1
1
Words:  
Cycles:  
Example  
1
1
REG  
XORWF  
1
To maintain upward compatibility  
with future PIC12C67X products,  
do not use this instruction.  
Before Instruction  
REG  
W
=
=
0xAF  
0xB5  
After Instruction  
REG  
W
=
=
0x1A  
0xB5  
1999 Microchip Technology Inc.  
DS30561B-page 81  
PIC12C67X  
NOTES:  
DS30561B-page 82  
1999 Microchip Technology Inc.  
PIC12C67X  
MPLAB allows you to:  
11.0 DEVELOPMENT SUPPORT  
The PICmicro® microcontrollers are supported with a  
full range of hardware and software development tools:  
• Edit your source files (either assembly or ‘C’)  
• One touch assemble (or compile) and download  
to PICmicro tools (automatically updates all  
project information)  
• Integrated Development Environment  
- MPLAB® IDE Software  
• Debug using:  
- source files  
• Assemblers/Compilers/Linkers  
- MPASM Assembler  
- absolute listing file  
- object code  
- MPLAB-C17 and MPLAB-C18 C Compilers  
- MPLINK/MPLIB Linker/Librarian  
• Simulators  
The ability to use MPLAB with Microchip’s simulator,  
MPLAB-SIM, allows a consistent platform and the abil-  
ity to easily switch from the cost-effective simulator to  
the full featured emulator with minimal retraining.  
- MPLAB-SIM Software Simulator  
• Emulators  
- MPLAB-ICE Real-Time In-Circuit Emulator  
- PICMASTER®/PICMASTER-CE In-Circuit  
11.2  
MPASM Assembler  
Emulator  
MPASM is a full featured universal macro assembler for  
all PICmicro MCU’s. It can produce absolute code  
directly in the form of HEX files for device program-  
mers, or it can generate relocatable objects for  
MPLINK.  
- ICEPIC™  
• In-Circuit Debugger  
- MPLAB-ICD for PIC16F877  
• Device Programmers  
MPASM has a command line interface and a Windows  
shell and can be used as a standalone application on a  
Windows 3.x or greater system. MPASM generates  
relocatable object files, Intel standard HEX files, MAP  
files to detail memory usage and symbol reference, an  
absolute LST file which contains source lines and gen-  
erated machine code, and a COD file for MPLAB  
debugging.  
- PRO MATE II Universal Programmer  
- PICSTART Plus Entry-Level Prototype  
Programmer  
• Low-Cost Demonstration Boards  
- SIMICE  
- PICDEM-1  
- PICDEM-2  
- PICDEM-3  
MPASM features include:  
- PICDEM-17  
- SEEVAL  
• MPASM and MPLINK are integrated into MPLAB  
projects.  
- KEELOQ  
• MPASM allows user defined macros to be created  
for streamlined assembly.  
11.1  
MPLAB Integrated Development  
Environment Software  
• MPASM allows conditional assembly for multi pur-  
pose source files.  
• MPASM directives allow complete control over the  
assembly process.  
The MPLAB IDE software brings an ease of software  
development previously unseen in the 8-bit microcon-  
troller market. MPLAB is a Windows -based applica-  
tion which contains:  
11.3  
MPLAB-C17 and MPLAB-C18  
C Compilers  
• Multiple functionality  
- editor  
The MPLAB-C17 and MPLAB-C18 Code Development  
Systems are complete ANSI ‘C’ compilers and inte-  
grated development environments for Microchip’s  
PIC17CXXX and PIC18CXXX family of microcontrol-  
lers, respectively. These compilers provide powerful  
integration capabilities and ease of use not found with  
other compilers.  
- simulator  
- programmer (sold separately)  
- emulator (sold separately)  
• A full featured editor  
• A project manager  
• Customizable tool bar and key mapping  
• A status bar  
For easier source level debugging, the compilers pro-  
vide symbol information that is compatible with the  
MPLAB IDE memory display.  
• On-line help  
1999 Microchip Technology Inc.  
DS30561B-page 83  
PIC12C67X  
Interchangeable processor modules allow the system  
to be easily reconfigured for emulation of different pro-  
cessors. The universal architecture of the MPLAB-ICE  
allows expansion to support new PICmicro microcon-  
trollers.  
11.4  
MPLINK/MPLIB Linker/Librarian  
MPLINK is a relocatable linker for MPASM and  
MPLAB-C17 and MPLAB-C18. It can link relocatable  
objects from assembly or C source files along with pre-  
compiled libraries using directives from a linker script.  
The MPLAB-ICE Emulator System has been designed  
as a real-time emulation system with advanced fea-  
tures that are generally found on more expensive devel-  
opment tools. The PC platform and Microsoft® Windows  
3.x/95/98 environment were chosen to best make these  
features available to you, the end user.  
MPLIB is a librarian for pre-compiled code to be used  
with MPLINK. When a routine from a library is called  
from another source file, only the modules that contains  
that routine will be linked in with the application. This  
allows large libraries to be used efficiently in many dif-  
ferent applications. MPLIB manages the creation and  
modification of library files.  
MPLAB-ICE 2000 is a full-featured emulator system  
with enhanced trace, trigger, and data monitoring fea-  
tures. Both systems use the same processor modules  
and will operate across the full operating speed range  
of the PICmicro MCU.  
MPLINK features include:  
• MPLINK works with MPASM and MPLAB-C17  
and MPLAB-C18.  
• MPLINK allows all memory areas to be defined as  
sections to provide link-time flexibility.  
11.7  
PICMASTER/PICMASTER CE  
The PICMASTER system from Microchip Technology is  
a full-featured, professional quality emulator system.  
This flexible in-circuit emulator provides a high-quality,  
universal platform for emulating Microchip 8-bit  
PICmicro microcontrollers (MCUs). PICMASTER sys-  
tems are sold worldwide, with a CE compliant model  
available for European Union (EU) countries.  
MPLIB features include:  
• MPLIB makes linking easier because single librar-  
ies can be included instead of many smaller files.  
• MPLIB helps keep code maintainable by grouping  
related modules together.  
• MPLIB commands allow libraries to be created  
and modules to be added, listed, replaced,  
deleted, or extracted.  
11.8  
ICEPIC  
ICEPIC is a low-cost in-circuit emulation solution for the  
Microchip Technology PIC16C5X, PIC16C6X,  
PIC16C7X, and PIC16CXXX families of 8-bit one-time-  
programmable (OTP) microcontrollers. The modular  
system can support different subsets of PIC16C5X or  
PIC16CXXX products through the use of  
interchangeable personality modules or daughter  
boards. The emulator is capable of emulating without  
target application circuitry being present.  
11.5  
MPLAB-SIM Software Simulator  
The MPLAB-SIM Software Simulator allows code  
development in a PC host environment by simulating  
the PICmicro series microcontrollers on an instruction  
level. On any given instruction, the data areas can be  
examined or modified and stimuli can be applied from  
a file or user-defined key press to any of the pins. The  
execution can be performed in single step, execute until  
break, or trace mode.  
11.9  
MPLAB-ICD In-Circuit Debugger  
MPLAB-SIM fully supports symbolic debugging using  
MPLAB-C17 and MPLAB-C18 and MPASM. The Soft-  
ware Simulator offers the flexibility to develop and  
debug code outside of the laboratory environment mak-  
ing it an excellent multi-project software development  
tool.  
Microchip’s In-Circuit Debugger, MPLAB-ICD, is a pow-  
erful, low-cost run-time development tool. This tool is  
based on the flash PIC16F877 and can be used to  
develop for this and other PICmicro microcontrollers  
from the PIC16CXXX family. MPLAB-ICD utilizes the  
In-Circuit Debugging capability built into the  
PIC16F87X. This feature, along with Microchip’s In-Cir-  
cuit Serial Programming protocol, offers cost-effective  
in-circuit flash programming and debugging from the  
graphical user interface of the MPLAB Integrated  
Development Environment. This enables a designer to  
develop and debug source code by watching variables,  
single-stepping and setting break points. Running at  
full speed enables testing hardware in real-time. The  
MPLAB-ICD is also a programmer for the flash  
PIC16F87X family.  
11.6  
MPLAB-ICE High Performance  
Universal In-Circuit Emulator with  
MPLAB IDE  
The MPLAB-ICE Universal In-Circuit Emulator is  
intended to provide the product development engineer  
with a complete microcontroller design tool set for  
PICmicro microcontrollers (MCUs). Software control of  
MPLAB-ICE is provided by the MPLAB Integrated  
Development Environment (IDE), which allows editing,  
“make” and download, and source debugging from a  
single environment.  
DS30561B-page 84  
1999 Microchip Technology Inc.  
PIC12C67X  
the PICDEM-1 board, on a PRO MATE II or  
PICSTART-Plus programmer, and easily test firm-  
ware. The user can also connect the PICDEM-1  
board to the MPLAB-ICE emulator and download the  
firmware to the emulator for testing. Additional proto-  
type area is available for the user to build some addi-  
tional hardware and connect it to the microcontroller  
socket(s). Some of the features include an RS-232  
interface, a potentiometer for simulated analog input,  
push-button switches and eight LEDs connected to  
PORTB.  
11.10 PRO MATE II Universal Programmer  
The PRO MATE II Universal Programmer is a full-fea-  
tured programmer capable of operating in stand-alone  
mode as well as PC-hosted mode. PRO MATE II is CE  
compliant.  
The PRO MATE II has programmable VDD and VPP  
supplies which allows it to verify programmed memory  
at VDD min and VDD max for maximum reliability. It has  
an LCD display for instructions and error messages,  
keys to enter commands and a modular detachable  
socket assembly to support various package types. In  
stand-alone mode the PRO MATE II can read, verify or  
program PICmicro devices. It can also set code-protect  
bits in this mode.  
11.14 PICDEM-2 Low-Cost PIC16CXX  
Demonstration Board  
The PICDEM-2 is a simple demonstration board that  
supports the PIC16C62, PIC16C64, PIC16C65,  
PIC16C73 and PIC16C74 microcontrollers. All the  
necessary hardware and software is included to  
run the basic demonstration programs. The user  
can program the sample microcontrollers provided  
with the PICDEM-2 board, on a PRO MATE II pro-  
grammer or PICSTART-Plus, and easily test firmware.  
The MPLAB-ICE emulator may also be used with the  
PICDEM-2 board to test firmware. Additional prototype  
area has been provided to the user for adding addi-  
tional hardware and connecting it to the microcontroller  
socket(s). Some of the features include a RS-232 inter-  
face, push-button switches, a potentiometer for simu-  
lated analog input, a Serial EEPROM to demonstrate  
usage of the I2C bus and separate headers for connec-  
tion to an LCD module and a keypad.  
11.11 PICSTART Plus Entry Level  
Development System  
The PICSTART programmer is an easy-to-use, low-  
cost prototype programmer. It connects to the PC via  
one of the COM (RS-232) ports. MPLAB Integrated  
Development Environment software makes using the  
programmer simple and efficient.  
PICSTART Plus supports all PICmicro devices with up  
to 40 pins. Larger pin count devices such as the  
PIC16C92X, and PIC17C76X may be supported with  
an adapter socket. PICSTART Plus is CE compliant.  
11.12 SIMICE Entry-Level  
Hardware Simulator  
SIMICE is an entry-level hardware development sys-  
tem designed to operate in a PC-based environment  
with Microchip’s simulator MPLAB-SIM. Both SIMICE  
and MPLAB-SIM run under Microchip Technology’s  
MPLAB Integrated Development Environment (IDE)  
software. Specifically, SIMICE provides hardware sim-  
ulation for Microchip’s PIC12C5XX, PIC12CE5XX, and  
PIC16C5X families of PICmicro 8-bit microcontrollers.  
SIMICE works in conjunction with MPLAB-SIM to pro-  
vide non-real-time I/O port emulation. SIMICE enables  
a developer to run simulator code for driving the target  
system. In addition, the target system can provide input  
to the simulator code. This capability allows for simple  
and interactive debugging without having to manually  
generate MPLAB-SIM stimulus files. SIMICE is a valu-  
able debugging tool for entry-level system develop-  
ment.  
11.15 PICDEM-3 Low-Cost PIC16CXXX  
Demonstration Board  
The PICDEM-3 is a simple demonstration board that  
supports the PIC16C923 and PIC16C924 in the PLCC  
package. It will also support future 44-pin PLCC  
microcontrollers with a LCD Module. All the neces-  
sary hardware and software is included to run the  
basic demonstration programs. The user can pro-  
gram the sample microcontrollers provided with  
the PICDEM-3 board, on a PRO MATE II program-  
mer or PICSTART Plus with an adapter socket, and  
easily test firmware. The MPLAB-ICE emulator may  
also be used with the PICDEM-3 board to test firm-  
ware. Additional prototype area has been provided to  
the user for adding hardware and connecting it to the  
microcontroller socket(s). Some of the features include  
an RS-232 interface, push-button switches, a potenti-  
ometer for simulated analog input, a thermistor and  
separate headers for connection to an external LCD  
module and a keypad. Also provided on the PICDEM-3  
board is an LCD panel, with 4 commons and 12 seg-  
ments, that is capable of displaying time, temperature  
and day of the week. The PICDEM-3 provides an addi-  
tional RS-232 interface and Windows 3.1 software for  
showing the demultiplexed LCD signals on a PC. A sim-  
ple serial interface allows the user to construct a hard-  
ware demultiplexer for the LCD signals.  
11.13 PICDEM-1 Low-Cost PICmicro  
Demonstration Board  
The PICDEM-1 is a simple board which demonstrates  
the capabilities of several of Microchip’s microcontrol-  
lers. The microcontrollers supported are: PIC16C5X  
(PIC16C54 to PIC16C58A), PIC16C61, PIC16C62X,  
PIC16C71, PIC16C8X, PIC17C42, PIC17C43 and  
PIC17C44. All necessary hardware and software is  
included to run basic demo programs. The users can  
program the sample microcontrollers provided with  
1999 Microchip Technology Inc.  
DS30561B-page 85  
PIC12C67X  
11.16 PICDEM-17  
The PICDEM-17 is an evaluation board that demon-  
strates the capabilities of several Microchip microcon-  
trollers,  
including  
PIC17C752,  
PIC17C756,  
PIC17C762, and PIC17C766. All necessary hardware  
is included to run basic demo programs, which are sup-  
plied on a 3.5-inch disk. A programmed sample is  
included, and the user may erase it and program it with  
the other sample programs using the PRO MATE II or  
PICSTART Plus device programmers and easily debug  
and test the sample code. In addition, PICDEM-17 sup-  
ports down-loading of programs to and executing out of  
external FLASH memory on board. The PICDEM-17 is  
also usable with the MPLAB-ICE or PICMASTER emu-  
lator, and all of the sample programs can be run and  
modified using either emulator. Additionally, a gener-  
ous prototype area is available for user hardware.  
11.17 SEEVAL Evaluation and Programming  
System  
The SEEVAL SEEPROM Designer’s Kit supports all  
Microchip 2-wire and 3-wire Serial EEPROMs. The kit  
includes everything necessary to read, write, erase or  
program special features of any Microchip SEEPROM  
product including Smart Serials and secure serials.  
The Total Endurance Disk is included to aid in trade-  
off analysis and reliability calculations. The total kit can  
significantly reduce time-to-market and result in an  
optimized system.  
11.18 KEELOQ Evaluation and  
Programming Tools  
KEELOQ evaluation and programming tools support  
Microchips HCS Secure Data Products. The HCS eval-  
uation kit includes an LCD display to show changing  
codes, a decoder to decode transmissions, and a pro-  
gramming interface to program test transmitters.  
DS30561B-page 86  
1999 Microchip Technology Inc.  
PIC12C67X  
TABLE 11-1: DEVELOPMENT TOOLS FROM MICROCHIP  
0
2 5 P 1 C M  
X X X C R M F  
X
H C S X X  
X X C 9 3  
C 5 X 2 X /  
C 4 X 2 X /  
2 X X 1 8 C I C P  
X X 7 1 7 C I C P  
X 4 C 7 C 1 P I  
X X 9 1 6 C I C P  
X 8 X 6 1 F C I P  
X 8 C 6 C 1 P I  
X X 7 1 6 C I C P  
X 7 C 6 C 1 P I  
X 2 6 F 6 C 1 P I  
X X C 6 X C 1 P I  
X 6 C 6 C 1 P I  
X 5 C 6 C 1 P I  
0
4 0 1 0 C I P  
X X C 2 X C 1 P I  
l s o o T e w f a t o r S s o t r a l  
E m r u g g b e e u D s r e m m r a g o P r  
s
K l a i t E d v n a s d r a B o o m D e  
1999 Microchip Technology Inc.  
DS30561B-page 87  
PIC12C67X  
NOTES:  
DS30561B-page 88  
1999 Microchip Technology Inc.  
PIC12C67X  
12.0 ELECTRICAL SPECIFICATIONS FOR PIC12C67X  
Absolute Maximum Ratings †  
Ambient temperature under bias...............................................................................................................–40° to +125°C  
Storage temperature ............................................................................................................................. –65°C to +150°C  
Voltage on any pin with respect to VSS (except VDD and MCLR)................................................... –0.3V to (VDD + 0.3V)  
Voltage on VDD with respect to VSS ................................................................................................................ 0 to +7.0V  
Voltage on MCLR with respect to VSS (Note 2)..................................................................................................0 to +14V  
Total power dissipation (Note 1)...........................................................................................................................700 mW  
Maximum current out of VSS pin ...........................................................................................................................200 mA  
Maximum current into VDD pin ..............................................................................................................................150 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 GPIO pins combined...................................................................................................100 mA  
Maximum current sourced by GPIO pins combined..............................................................................................100 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 to maximum rating conditions for  
extended periods may affect device reliability.  
1999 Microchip Technology Inc.  
DS30561B-page 89  
PIC12C67X  
FIGURE 12-1: PIC12C67X VOLTAGE-FREQUENCY GRAPH, -40°C TA < 0°C, +70°C <TA +125°C  
6.0  
5.5  
5.0  
4.5  
VDD  
(Volts)  
4.0  
3.5  
3.0  
2.5  
2.0  
0
4
10  
20  
25  
Frequency (MHz)  
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.  
2: The maximum rated speed of the part limits the permissible combinations of voltage and frequency.  
Please reference the Product Identification System section for the maximum rated speed of the parts.  
FIGURE 12-2: PIC12C67X VOLTAGE-FREQUENCY GRAPH, 0°C TA +70°C  
6.0  
5.5  
5.0  
4.5  
VDD  
(Volts)  
4.0  
3.5  
3.0  
2.5  
0
4
10  
20  
25  
Frequency (MHz)  
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.  
2: The maximum rated speed of the part limits the permissible combinations of voltage and frequency.  
Please reference the Product Identification System section for the maximum rated speed of the parts.  
DS30561B-page 90  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 12-3: PIC12LC67X VOLTAGE-FREQUENCY GRAPH, -40°C TA +85°C  
6.0  
5.5  
5.0  
4.5  
4.0  
3.5  
3.0  
VDD  
(Volts)  
2.5  
2.0  
20  
0
4
10  
25  
Frequency (MHz)  
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.  
2: The maximum rated speed of the part limits the permissible combinations of voltage and frequency.  
Please reference the Product Identification System section for the maximum rated speed of the parts.  
1999 Microchip Technology Inc.  
DS30561B-page 91  
PIC12C67X  
12.1  
DC Characteristics:  
PIC12C671/672 (Commercial, Industrial, Extended)  
PIC12CE673/674 (Commercial, Industrial, Extended)  
Standard Operating Conditions (unless otherwise specified)  
DC CHARACTERISTICS  
Operating Temperature  
0°C TA +70°C (commercial)  
–40°C TA +85°C (industrial)  
–40°C TA +125°C (extended)  
Typ(1)  
Parm  
No.  
Characteristic  
Sym Min  
Max Units  
Conditions  
D001  
D002  
Supply Voltage  
VDD  
VDR  
3.0  
5.5  
V
V
RAM Data Retention  
Voltage(2)  
1.5*  
Device in SLEEP mode  
D003  
D004  
VDD Start Voltage to ensure VPOR  
Power-on Reset  
VSS  
V
See section on Power-on Reset for details  
VDD Rise Rate to ensure  
Power-on Reset  
SVDD 0.05*  
V/ms See section on Power-on Reset for details  
Supply Current(3)  
D010  
IDD  
1.2  
1.2  
2.2  
19  
2.5  
2.5  
8
mA FOSC = 4MHz, VDD = 3.0V  
XT and EXTRC mode (Note 4)  
mA FOSC = 4MHz, VDD = 3.0V  
INTRC mode (Note 6)  
mA FOSC = 10MHz, VDD = 5.5V  
HS mode  
µA FOSC = 32kHz, VDD = 3.0V, WDT disabled  
LP mode, Commercial Temperature  
µA FOSC = 32kHz, VDD = 3.0V, WDT disabled  
LP mode, Industrial Temperature  
µA FOSC = 32kHz, VDD = 3.0V, WDT disabled  
LP mode, Extended Temperature  
D010C  
D010A  
29  
37  
60  
19  
32  
Power-down Current(5)  
Watchdog Timer Current  
D020  
D021  
D021B  
IPD  
0.25  
0.25  
2
0.5  
0.8  
3
6
7
14  
8
9
16  
µA VDD = 3.0V, Commercial, WDT disabled  
µA VDD = 3.0V, Industrial, WDT disabled  
µA VDD = 3.0V, Extended, WDT disabled  
µA VDD = 5.5V, Commercial, WDT disabled  
µA VDD = 5.5V, Industrial, WDT disabled  
µA VDD = 5.5V, Extended, WDT disabled  
D022  
D028  
IWDT  
IEE  
2.2  
2.2  
4
5
6
11  
µA VDD = 3.0V, Commercial  
µA VDD = 3.0V, Industrial  
µA VDD = 3.0V, Extended  
Supply Current(3)  
During read/write to  
EEPROM peripheral  
0.1  
0.2  
mA FOSC = 4MHz, VDD = 5.5V, SCL = 400kHz  
For PIC12CE673/674 only  
*
These parameters are characterized but not tested.  
Note 1: Data in Typical ("Typ") column is based on characterization results at 25°C. This data is for design guidance only and is not  
tested.  
2: This is the limit to which VDD can be lowered in SLEEP mode without losing RAM data.  
3: The supply current is mainly a function of the operating voltage and frequency. Other factors such as bus loading, oscillator  
type, bus rate, internal code execution pattern and temperature also have an impact on the current consumption.  
a) The test conditions for all IDD measurements in active operation mode are:  
OSC1 = external square wave, from rail-to-rail; all I/O pins tristated, pulled to VSS, T0CKI = VDD,  
MCLR = VDD; WDT disabled.  
b) For standby current measurements, the conditions are the same, except that the device is in SLEEP mode.  
4: For EXTRC osc configuration, current through REXT is not included. The current through the resistor can be estimated by the  
formula:  
Ir = VDD/2REXT (mA) with REXT in kOhm.  
5: 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 hi-impedance state and tied to VDD or VSS.  
6: INTRC calibration value is for 4MHz nominal at 5V, 25°C.  
DS30561B-page 92  
1999 Microchip Technology Inc.  
PIC12C67X  
Standard Operating Conditions (unless otherwise specified)  
DC CHARACTERISTICS  
Operating Temperature  
0°C TA +70°C (commercial)  
–40°C TA +85°C (industrial)  
–40°C TA +125°C (extended)  
Typ(1)  
Parm  
No.  
Characteristic  
Sym Min  
Max Units  
Conditions  
LP Oscillator Operating  
Frequency  
INTRC/EXTRC Oscillator  
Operating Frequency  
XT Oscillator Operating  
Frequency  
FOSC  
0
0
200 kHz All temperatures  
4(6)  
4
MHz All temperatures  
MHz All temperatures  
MHz All temperatures  
HS Oscillator Operating  
Frequency  
0
10  
*
These parameters are characterized but not tested.  
Note 1: Data in Typical ("Typ") column is based on characterization results at 25°C. This data is for design guidance only and is not  
tested.  
2: This is the limit to which VDD can be lowered in SLEEP mode without losing RAM data.  
3: The supply current is mainly a function of the operating voltage and frequency. Other factors such as bus loading, oscillator  
type, bus rate, internal code execution pattern, and temperature also have an impact on the current consumption.  
a) The test conditions for all IDD measurements in active operation mode are:  
OSC1 = external square wave, from rail-to-rail; all I/O pins tristated, pulled to VSS, T0CKI = VDD,  
MCLR = VDD; WDT disabled.  
b) For standby current measurements, the conditions are the same, except that the device is in SLEEP mode.  
4: For EXTRC osc configuration, current through REXT is not included. The current through the resistor can be estimated by the  
formula:  
Ir = VDD/2REXT (mA) with REXT in kOhm.  
5: 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 hi-impedance state and tied to VDD or VSS.  
6: INTRC calibration value is for 4MHz nominal at 5V, 25°C.  
1999 Microchip Technology Inc.  
DS30561B-page 93  
PIC12C67X  
12.2  
DC Characteristics:  
PIC12LC671/672 (Commercial, Industrial)  
PIC12LCE673/674 (Commercial, Industrial)  
Standard Operating Conditions (unless otherwise specified)  
Operating temperature 0°C TA +70°C (commercial)  
–40°C TA +85°C (industrial)  
DC CHARACTERISTICS  
Param  
No.  
Characteristic  
Sym Min Typ† Max Units  
Conditions  
D001  
D002  
Supply Voltage  
RAM Data Retention  
Voltage(2)  
VDD  
VDR  
2.5  
5.5  
V
V
1.5*  
VSS  
Device in SLEEP mode  
See section on Power-on Reset for details  
D003  
D004  
VDD Start Voltage to  
ensure Power-on Reset  
VPOR  
V
VDD Rise Rate to ensure SVDD 0.05*  
V/ms See section on Power-on Reset for details  
Power-on Reset  
Supply Current(3)  
D010  
IDD  
0.4  
0.4  
15  
2.1  
2.1  
33  
mA FOSC = 4MHz, VDD = 2.5V  
XT and EXTRC mode (Note 4)  
mA FOSC = 4MHz, VDD = 2.5V  
INTRC mode (Note 6)  
µA FOSC = 32kHz, VDD = 2.5V, WDT disabled  
LP mode, Industrial Temperature  
D010C  
D010A  
Power-down Current(5)  
D020  
D021  
D021B  
IPD  
0.2  
0.2  
5
6
µA VDD = 2.5V, Commercial  
µA VDD = 2.5V, Industrial  
Watchdog Timer Current IWDT  
2.0  
2.0  
4
6
µA VDD = 2.5V, Commercial  
µA VDD = 2.5V, Industrial  
LP Oscillator Operating FOSC  
Frequency  
INTRC/EXTRC Oscillator  
Operating Frequency  
XT Oscillator Operating  
Frequency  
0
0
200 kHz All temperatures  
4(6)  
MHz All temperatures  
MHz All temperatures  
MHz All temperatures  
4
HS Oscillator Operating  
Frequency  
0
10  
*
These parameters are characterized but not tested.  
Note 1: Data in Typical ("Typ") column is based on characterization results at 25°C. This data is for design guidance only and is not  
tested.  
2: This is the limit to which VDD can be lowered in SLEEP mode without losing RAM data.  
3: The supply current is mainly a function of the operating voltage and frequency. Other factors such as bus loading, oscillator  
type, bus rate, internal code execution pattern, and temperature also have an impact on the current consumption.  
a) The test conditions for all IDD measurements in active operation mode are:  
OSC1 = external square wave, from rail-to-rail; all I/O pins tristated, pulled to VSS, T0CKI = VDD,  
MCLR = VDD; WDT disabled.  
b) For standby current measurements, the conditions are the same, except that the device is in SLEEP mode.  
4: For EXTRC osc configuration, current through REXT is not included. The current through the resistor can be estimated by the  
formula:  
Ir = VDD/2REXT (mA) with REXT in kOhm.  
5: 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 hi-impedance state and tied to VDD or VSS.  
6: INTRC calibration value is for 4MHz nominal at 5V, 25°C.  
DS30561B-page 94  
1999 Microchip Technology Inc.  
PIC12C67X  
12.3  
DC CHARACTERISTICS:  
PIC12C671/672 (Commercial, Industrial, Extended)  
PIC12CE673/674 (Commercial, Industrial, Extended)  
Standard Operating Conditions (unless otherwise specified)  
Operating temperature  
0°C TA +70°C (commercial)  
–40°C TA +85°C (industrial)  
–40°C TA +125°C (extended)  
DC CHARACTERISTICS  
Operating voltage VDD range as described in DC spec Section 12.1 and  
Section 12.2.  
Param  
No.  
Characteristic  
Sym  
Min  
Typ† Max Units  
Conditions  
Input Low Voltage  
I/O ports  
VIL  
D030  
D031  
with TTL buffer  
VSS  
VSS  
VSS  
VSS  
0.8V  
V
V
V
V
For 4.5V VDD 5.5V  
0.15VDD  
0.2VDD  
0.2VDD  
otherwise  
with Schmitt Trigger buffer  
D032 MCLR, GP2/T0CKI/AN2/INT  
(in EXTRC mode)  
D033 OSC1 (in EXTRC mode)  
VSS  
VSS  
0.2VDD  
0.3VDD  
Note 1  
Note 1  
D033 OSC1 (in XT, HS, and LP)  
Input High Voltage  
I/O ports  
V
VIH  
D040  
D040A  
D041  
with TTL buffer  
2.0V  
0.25VDD + 0.8V  
0.8VDD  
VDD  
VDD  
VDD  
VDD  
VDD  
VDD  
V
V
V
V
V
V
4.5V VDD 5.5V  
otherwise  
with Schmitt Trigger buffer  
For entire VDD range  
D042 MCLR, GP2/T0CKI/AN2/INT  
D042A OSC1 (XT, HS, and LP)  
D043 OSC1 (in EXTRC mode)  
Input Leakage Current (Notes 2, 3)  
D060 I/O ports  
0.8VDD  
0.7VDD  
Note 1  
0.9VDD  
IIL  
+1  
µA VSS VPIN VDD, Pin at  
hi-impedance  
D061 GP3/MCLR (Note 5)  
D061A GP3 (Note 6)  
D062 GP2/T0CKI  
+30  
+5  
µA VSS VPIN VDD  
µA VSS VPIN VDD  
µA VSS VPIN VDD  
+5  
+5  
D063 OSC1  
µA VSS VPIN VDD, XT, HS, and  
LP osc configuration  
D070 GPIO weak pull-up current (Note 4)  
MCLR pull-up current  
IPUR  
50  
250  
400  
30  
µA VDD = 5V, VPIN = VSS  
µA VDD = 5V, VPIN = VSS  
Output Low Voltage  
D080 I/O ports  
VOL  
0.6  
0.6  
0.6  
0.6  
V
V
V
V
IOL = 8.5 mA, VDD = 4.5V,  
–40°C to +85°C  
D080A  
IOL = 7.0 mA, VDD = 4.5V,  
–40°C to +125°C  
D083 OSC2/CLKOUT  
D083A  
IOL = 1.6 mA, VDD = 4.5V,  
–40°C to +85°C  
IOL = 1.2 mA, VDD = 4.5V,  
–40°C to +125°C  
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: In EXTRC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended that the PIC12C67X  
be driven with external clock in RC mode.  
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent  
normal operating conditions. Higher leakage current may be measured at different input voltages.  
3: Negative current is defined as coming out of the pin.  
4: Does not include GP3. For GP3 see parameters D061 and D061A.  
5: This spec. applies to GP3/MCLR configured as external MCLR and GP3/MCLR configured as input with internal pull-up  
enabled.  
6: This spec. applies when GP3/MCLR is configured as an input with pull-up disabled. The leakage current of the MCLR circuit  
is higher than the standard I/O logic.  
1999 Microchip Technology Inc.  
DS30561B-page 95  
PIC12C67X  
Standard Operating Conditions (unless otherwise specified)  
Operating temperature  
0°C TA +70°C (commercial)  
–40°C TA +85°C (industrial)  
–40°C TA +125°C (extended)  
DC CHARACTERISTICS  
Operating voltage VDD range as described in DC spec Section 12.1 and  
Section 12.2.  
Param  
No.  
Characteristic  
Output High Voltage  
Sym  
Min  
Typ† Max Units  
Conditions  
D090 I/O ports (Note 3)  
VOH  
VDD - 0.7  
VDD - 0.7  
VDD - 0.7  
VDD - 0.7  
V
V
V
V
IOH = -3.0 mA, VDD = 4.5V,  
–40°C to +85°C  
D090A  
IOH = -2.5 mA, VDD = 4.5V,  
–40°C to +125°C  
D092 OSC2/CLKOUT  
D092A  
IOH = 1.3 mA, VDD = 4.5V,  
–40°C to +85°C  
IOH = 1.0 mA, VDD = 4.5V,  
–40°C to +125°C  
Capacitive Loading Specs on  
Output Pins  
D100 OSC2 pin  
COSC2  
15  
50  
pF In XT and LP modes when  
external clock is used to drive  
OSC1.  
D101 All I/O pins  
CIO  
pF  
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: In EXTRC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended that the PIC12C67X  
be driven with external clock in RC mode.  
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent  
normal operating conditions. Higher leakage current may be measured at different input voltages.  
3: Negative current is defined as coming out of the pin.  
4: Does not include GP3. For GP3 see parameters D061 and D061A.  
5: This spec. applies to GP3/MCLR configured as external MCLR and GP3/MCLR configured as input with internal pull-up  
enabled.  
6: This spec. applies when GP3/MCLR is configured as an input with pull-up disabled. The leakage current of the MCLR circuit  
is higher than the standard I/O logic.  
DS30561B-page 96  
1999 Microchip Technology Inc.  
PIC12C67X  
12.4  
DC CHARACTERISTICS:  
PIC12LC671/672 (Commercial, Industrial)  
PIC12LCE673/674 (Commercial, Industrial)  
Standard Operating Conditions (unless otherwise specified)  
Operating temperature  
0°C TA +70°C (commercial)  
–40°C TA +85°C (industrial)  
DC CHARACTERISTICS  
Operating voltage VDD range as described in DC spec Section 12.1 and  
Section 12.2.  
Param  
No.  
Characteristic  
Sym  
Min  
Typ† Max  
Units  
Conditions  
Input Low Voltage  
I/O ports  
VIL  
D030  
with TTL buffer  
VSS  
VSS  
VSS  
VSS  
0.8V  
V
V
V
V
For 4.5V VDD 5.5V  
0.15VDD  
0.2VDD  
0.2VDD  
otherwise  
D031  
D032  
with Schmitt Trigger buffer  
MCLR, GP2/T0CKI/AN2/INT  
(in EXTRC mode)  
D033  
D033  
OSC1 (in EXTRC mode)  
OSC1 (in XT, HS, and LP)  
Input High Voltage  
I/O ports  
VSS  
VSS  
0.2VDD  
0.3VDD  
V
V
Note 1  
Note 1  
VIH  
D040  
D040A  
D041  
D042  
with TTL buffer  
2.0V  
0.25VDD + 0.8V  
0.8VDD  
VDD  
VDD  
VDD  
VDD  
VDD  
VDD  
V
V
V
V
V
V
4.5V VDD 5.5V  
otherwise  
with Schmitt Trigger buffer  
MCLR, GP2/T0CKI/AN2/INT  
For entire VDD range  
0.8VDD  
D042A OSC1 (XT, HS, and LP)  
0.7VDD  
Note 1  
D043  
D060  
D061  
OSC1 (in EXTRC mode)  
Input Leakage Current (Notes 2, 3)  
I/O ports  
0.9VDD  
IIL  
+1  
µA Vss VPIN VDD, Pin at  
hi-impedance  
GP3/MCLR (Note 5)  
+30  
+5  
µA Vss VPIN VDD  
D061A GP3 (Note 6)  
µA Vss VPIN VDD  
µA Vss VPIN VDD  
D062  
D063  
GP2/T0CKI  
OSC1  
+5  
+5  
µA Vss VPIN VDD, XT, HS and  
LP osc configuration  
D070  
GPIO weak pull-up current (Note 4)  
MCLR pull-up current  
Output Low Voltage  
I/O ports  
IPUR  
50  
250  
400  
30  
µA VDD = 5V, VPIN = VSS  
µA VDD = 5V, VPIN = VSS  
D080  
D080A  
D083  
D083A  
VOL  
0.6  
0.6  
0.6  
0.6  
V
V
V
V
IOL = 8.5 mA, VDD = 4.5V,  
–40°C to +85°C  
IOL = 7.0 mA, VDD = 4.5V,  
–40°C to +125°C  
OSC2/CLKOUT  
IOL = TBD, VDD = 4.5V,  
–40°C to +85°C  
IOL = TBD, VDD = 4.5V,  
–40°C to +125°C  
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: In EXTRC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended that the PIC12C67X  
be driven with external clock in RC mode.  
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent nor-  
mal operating conditions. Higher leakage current may be measured at different input voltages.  
3: Negative current is defined as coming out of the pin.  
4: Does not include GP3. For GP3 see parameters D061 and D061A.  
5: This spec. applies to GP3/MCLR configured as external MCLR and GP3/MCLR configured as input with internal pull-up  
enabled.  
6: This spec. applies when GP3/MCLR is configured as an input with pull-up disabled. The leakage current of the MCLR circuit is  
higher than the standard I/O logic.  
1999 Microchip Technology Inc.  
DS30561B-page 97  
PIC12C67X  
Standard Operating Conditions (unless otherwise specified)  
Operating temperature  
0°C TA +70°C (commercial)  
–40°C TA +85°C (industrial)  
DC CHARACTERISTICS  
Operating voltage VDD range as described in DC spec Section 12.1 and  
Section 12.2.  
Param  
No.  
Characteristic  
Sym  
Min  
Typ† Max  
Units  
Conditions  
Output High Voltage  
D090  
I/O ports (Note 3)  
VOH  
VDD - 0.7  
VDD - 0.7  
VDD - 0.7  
VDD - 0.7  
V
V
V
V
IOH = -3.0 mA, VDD = 4.5V,  
–40°C to +85°C  
D090A  
D092  
IOH = -2.5 mA, VDD = 4.5V,  
–40°C to +125°C  
IOH = TBD, VDD = 4.5V,  
–40°C to +85°C  
OSC2/CLKOUT  
D092A  
IOH = TBD, VDD = 4.5V,  
–40°C to +125°C  
Capacitive Loading Specs on  
Output Pins  
D100  
OSC2 pin  
COSC2  
CIO  
15  
50  
pF In XT and LP modes when  
external clock is used to drive  
OSC1.  
pF  
D101  
All I/O pins  
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: In EXTRC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended that the PIC12C67X  
be driven with external clock in RC mode.  
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent nor-  
mal operating conditions. Higher leakage current may be measured at different input voltages.  
3: Negative current is defined as coming out of the pin.  
4: Does not include GP3. For GP3 see parameters D061 and D061A.  
5: This spec. applies to GP3/MCLR configured as external MCLR and GP3/MCLR configured as input with internal pull-up  
enabled.  
6: This spec. applies when GP3/MCLR is configured as an input with pull-up disabled. The leakage current of the MCLR circuit is  
higher than the standard I/O logic.  
DS30561B-page 98  
1999 Microchip Technology Inc.  
PIC12C67X  
12.5  
Timing Parameter Symbology  
The timing parameter symbols have been created following one of the following formats:  
1. TppS2ppS  
3. TCC:ST  
4. Ts  
(I2C specifications only)  
(I2C specifications only)  
2. TppS  
T
F
Frequency  
T
Time  
Lowercase letters (pp) and their meanings:  
pp  
cc  
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 (Hi-impedance)  
Low  
Valid  
L
Hi-impedance  
I2C only  
AA  
output access  
Bus free  
High  
Low  
High  
Low  
BUF  
TCC:ST (I2C specifications only)  
CC  
HD  
ST  
DAT  
STA  
Hold  
SU  
Setup  
DATA input hold  
START condition  
STO  
STOP condition  
FIGURE 12-4: LOAD CONDITIONS  
Load condition 1  
Load condition 2  
VDD/2  
RL  
CL  
CL  
Pin  
Pin  
VSS  
VSS  
RL = 464Ω  
CL = 50 pF for all pins except OSC2  
15 pF for OSC2 output  
1999 Microchip Technology Inc.  
DS30561B-page 99  
PIC12C67X  
12.6  
Timing Diagrams and Specifications  
FIGURE 12-5: EXTERNAL CLOCK TIMING  
Q4  
Q1  
Q2  
Q3  
Q4  
4
Q1  
OSC1  
1
3
4
3
2
CLKOUT  
TABLE 12-1: CLOCK TIMING REQUIREMENTS  
Parameter Sym Characteristic  
No.  
Min Typ†  
Max  
Units Conditions  
FOSC External CLKIN Frequency  
DC  
DC  
DC  
DC  
DC  
.455  
4
4
4
MHz XT and EXTRC osc mode  
MHz HS osc mode (PIC12CE67X-04)  
MHz HS osc mode (PIC12CE67X-10)  
kHz LP osc mode  
(Note 1)  
10  
200  
4
Oscillator Frequency  
(Note 1)  
MHz EXTRC osc mode  
4
MHz XT osc mode  
4
MHz HS osc mode (PIC12CE67X-04)  
MHz HS osc mode (PIC12CE67X-10)  
kHz LP osc mode  
4
10  
200  
5
1
TOSC External CLKIN Period  
250  
250  
100  
5
ns  
ns  
ns  
µs  
ns  
ns  
ns  
ns  
µs  
ns  
ns  
µs  
ns  
ns  
ns  
ns  
XT and EXTRC osc mode  
HS osc mode (PIC12CE67X-04)  
HS osc mode (PIC12CE67X-10)  
LP osc mode  
(Note 1)  
Oscillator Period  
(Note 1)  
250  
250  
250  
100  
5
EXTRC osc mode  
XT osc mode  
10,000  
250  
250  
HS osc mode (PIC12CE67X-04)  
HS osc mode (PIC12CE67X-10)  
LP osc mode  
2
3
TCY Instruction Cycle Time (Note 1) 400  
DC  
TCY = 4/FOSC  
TosL, External Clock in (OSC1) High  
TosH or Low Time  
50  
2.5  
10  
XT oscillator  
LP oscillator  
HS oscillator  
4
TosR, External Clock in (OSC1) Rise  
TosF or Fall Time  
25  
XT oscillator  
50  
LP oscillator  
15  
HS oscillator  
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 exe-  
cuting 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/CLKIN pin.  
When an external clock input is used, the "Max." cycle time limit is "DC" (no clock) for all devices. OSC2 is discon-  
nected (has no loading) for the PIC12C67X.  
DS30561B-page 100  
1999 Microchip Technology Inc.  
PIC12C67X  
TABLE 12-2: CALIBRATED INTERNAL RC FREQUENCIES -PIC12C671, PIC12C672, PIC12CE673,  
PIC12CE674, PIC12LC671,  
PIC12LC672, PIC12LCE673,  
PIC12LCE674  
AC Characteristics  
Standard Operating Conditions (unless otherwise specified)  
Operating Temperature  
0°C TA +70°C (commercial),  
–40°C TA +85°C (industrial),  
–40°C TA +125°C (extended)  
Operating Voltage VDD range is described in Section 10.1  
Parameter  
Sym  
Typ(1)  
Characteristic  
Min*  
Max* Units  
Conditions  
MHz VDD = 5.0V  
MHz VDD = 2.5V  
No.  
Internal Calibrated RC Frequency  
3.65  
4.00  
4.28  
4.31  
Internal Calibrated RC Frequency  
3.55  
4.00  
*
These parameters are characterized but not tested.  
Note 1: Data in the Typical (“Typ”) column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only  
and are not tested.  
1999 Microchip Technology Inc.  
DS30561B-page 101  
PIC12C67X  
FIGURE 12-6: CLKOUT AND I/O TIMING  
Q1  
Q2  
Q3  
Q4  
OSC1  
11  
10  
CLKOUT  
13  
14  
12  
18  
19  
16  
I/O Pin  
(input)  
15  
17  
I/O Pin  
new value  
old value  
(output)  
20, 21  
Note: Refer to Figure 12-4 for load conditions.  
TABLE 12-3: CLKOUT AND I/O TIMING REQUIREMENTS  
Param Sym  
No.  
Characteristic  
Min  
Typ†  
Max  
Units Conditions  
10*  
11*  
12*  
13*  
14*  
15*  
16*  
17*  
18*  
18A*  
TosH2ckL OSC1to CLKOUT↓  
TosH2ckH OSC1to CLKOUT↑  
75  
75  
35  
35  
50  
200  
200  
100  
100  
ns Note 1  
ns Note 1  
ns Note 1  
ns Note 1  
TckR  
TckF  
CLKOUT rise time  
CLKOUT fall time  
TckL2ioV CLKOUT to Port out valid  
0.5TCY + 20 ns Note 1  
TioV2ckH Port in valid before CLKOUT ↑  
TckH2ioI Port in hold after CLKOUT ↑  
TOSC + 200  
ns Note 1  
0
ns Note 1  
TosH2ioV OSC1(Q1 cycle) to Port out valid  
TosH2ioI OSC1(Q2 cycle) to Port PIC12C67X  
150  
ns  
ns  
ns  
100  
200  
input invalid (I/O in hold  
time)  
PIC12LC67X  
19*  
TioV2osH Port input valid to OSC1(I/O in setup  
0
ns  
time)  
20*  
20A*  
21*  
TioR  
TioF  
Port output rise time  
Port output fall time  
PIC12C67X  
PIC12LC67X  
PIC12C67X  
PIC12LC67X  
10  
10  
40  
80  
40  
80  
ns  
ns  
ns  
ns  
ns  
ns  
21A*  
22††*  
23††*  
Tinp  
Trbp  
GP2/INT pin high or low time  
TCY  
TCY  
GP0/GP1/GP3 change INT high or low  
time  
*
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.  
†† These parameters are asynchronous events not related to any internal clock edge.  
Note 1: Measurements are taken in EXTRC and INTRC modes where CLKOUT output is 4 x TOSC.  
DS30561B-page 102  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 12-7: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, AND POWER-UP  
TIMER TIMING  
VDD  
MCLR  
30  
Internal  
POR  
33  
PWRT  
Timeout  
32  
OSC  
Timeout  
Internal  
RESET  
Watchdog  
Timer  
RESET  
36  
34  
31  
34  
I/O Pins  
TABLE 12-4: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER  
Parameter  
No.  
Sym Characteristic  
Min  
Typ†  
Max Units  
Conditions  
30  
TmcL MCLR Pulse Width (low)  
2
µs VDD = 5V, 40°C to +125°C  
ms VDD = 5V, 40°C to +125°C  
31*  
Twdt  
Watchdog Timer Time-out Period  
7
18  
33  
(No Prescaler)  
32  
33*  
34  
Tost  
Oscillation Start-up Timer Period  
28  
1024TOSC  
TOSC = OSC1 period  
Tpwrt Power up Timer Period  
72  
132  
2.1  
ms VDD = 5V, 40°C to +125°C  
µs  
TIOZ I/O Hi-impedance from MCLR  
Low or Watchdog Timer Reset  
*
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.  
1999 Microchip Technology Inc.  
DS30561B-page 103  
PIC12C67X  
FIGURE 12-8: TIMER0 CLOCK TIMINGS  
GP2/T0CKI  
41  
40  
42  
TMR0  
Note: Refer to Figure 12-4 for load conditions.  
TABLE 12-5: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS  
Param  
No.  
Sym  
Characteristic  
Min  
Typ† Max Units  
Conditions  
40*  
41*  
42*  
Tt0H  
T0CKI High Pulse Width No Prescaler  
0.5TCY + 20  
10  
ns  
ns  
ns  
ns  
ns  
ns  
Must also meet  
parameter 42  
With Prescaler  
Tt0L  
Tt0P  
T0CKI Low Pulse Width  
T0CKI Period  
No Prescaler  
With Prescaler  
No Prescaler  
0.5TCY + 20  
10  
Must also meet  
parameter 42  
TCY + 40  
With Prescaler Greater of:  
20 or TCY + 40  
N = prescale  
value (2, 4,...,  
256)  
N
48  
*
TCKE2tmr1 Delay from external clock edge to timer  
increment  
2TOSC  
7Tos  
c
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.  
TABLE 12-6: GPIO PULL-UP RESISTOR RANGES  
VDD (Volts)  
Temperature (°C)  
Min  
Typ  
Max  
Units  
GP0/GP1  
2.5  
–40  
25  
38K  
42K  
42K  
50K  
15K  
18K  
19K  
22K  
42K  
48K  
49K  
55K  
17K  
20K  
22K  
24K  
63K  
63K  
63K  
63K  
20K  
23K  
25K  
28K  
85  
125  
–40  
25  
5.5  
85  
125  
GP3  
2.5  
5.5  
–40  
25  
285K  
343K  
368K  
431K  
247K  
288K  
306K  
351K  
346K  
414K  
457K  
504K  
292K  
341K  
371K  
407K  
417K  
532K  
532K  
593K  
360K  
437K  
448K  
500K  
85  
125  
–40  
25  
85  
125  
*
These parameters are characterized but not tested.  
DS30561B-page 104  
1999 Microchip Technology Inc.  
PIC12C67X  
TABLE 12-7: A/D CONVERTER CHARACTERISTICS:  
PIC12C671/672-04/PIC12CE673/674-04 (COMMERCIAL, INDUSTRIAL, EXTENDED)  
PIC12C671/672-10/PIC12CE673/674-10 (COMMERCIAL, INDUSTRIAL, EXTENDED)  
PIC12LC671/672-04/PIC12LCE673/674-04 (COMMERCIAL, INDUSTRIAL)  
Param Sym Characteristic  
No.  
Min  
Typ†  
Max  
Units  
Conditions  
A01  
A02  
A03  
NR  
EABS Total absolute error  
EIL Integral linearity error  
Resolution  
8-bits  
< ±1  
< ±1  
bit  
VREF = VDD = 5.12V,  
VSS VAIN VREF  
LSb VREF = VDD = 5.12V,  
VSS VAIN VREF  
LSb  
LSb  
LSb  
LSb  
VREF = VDD = 5.12V,  
VSS VAIN VREF  
A04  
A05  
A06  
EDL Differential linearity error  
EFS Full scale error  
< ±1  
< ±1  
< ±1  
VREF = VDD = 5.12V,  
VSS VAIN VREF  
VREF = VDD = 5.12V,  
VSS VAIN VREF  
EOFF Offset error  
VREF = VDD = 5.12V,  
VSS VAIN VREF  
A10  
A20  
Monotonicity  
guaranteed  
(Note 3)  
V
VSS VAIN VREF  
VREF Reference voltage  
VAIN Analog input voltage  
2.5V  
VDD + 0.3  
A25  
A30  
VSS - 0.3  
VREF + 0.3  
V
ZAIN Recommended impedance of  
10.0  
kΩ  
analog voltage source  
A40  
A50  
IAD A/D conversion  
current (VDD)  
PIC12C67X  
180  
90  
µA Average current con-  
sumption when A/D is on.  
(Note 1)  
PIC12LC67X  
µA  
IREF VREF input current (Note 2)  
10  
1000  
µA During VAIN acquisition.  
Based on differential of  
VHOLD to VAIN to charge  
CHOLD, see Section 8.1.  
10  
µA During A/D Conversion  
cycle  
*
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: When A/D is off, it will not consume any current other than minor leakage current. The power-down current spec  
includes any such leakage from the A/D module.  
2: VREF current is from GP1 pin or VDD pin, whichever is selected as reference input.  
3: The A/D conversion result never decreases with an increase in the Input Voltage, and has no missing codes.  
1999 Microchip Technology Inc.  
DS30561B-page 105  
PIC12C67X  
FIGURE 12-9: A/D CONVERSION TIMING  
BSF ADCON0, GO  
1 TCY  
(TOSC/2)(1)  
134  
131  
130  
Q4  
132  
A/D CLK  
7
6
5
4
3
2
1
0
A/D DATA  
NEW_DATA  
DONE  
OLD_DATA  
ADRES  
ADIF  
GO  
SAMPLING STOPPED  
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.  
TABLE 12-8: A/D CONVERSION REQUIREMENTS  
Param Sym Characteristic  
No.  
Min  
Typ†  
Max Units  
Conditions  
130  
TAD  
A/D clock period  
PIC12C67X  
PIC12LC67X  
PIC12C67X  
PIC12LC67X  
1.6  
2.0  
2.0  
3.0  
11  
µs TOSC based, VREF 3.0V  
µs TOSC based, VREF full range  
µs A/D RC Mode  
4.0  
6.0  
6.0  
9.0  
11  
µs A/D RC Mode  
131  
132  
TCNV Conversion time (not including S/H  
TAD  
time) (Note 1)  
TACQ Acquisition time  
Note 2  
5*  
20  
µs  
µs The minimum time is the  
amplifier setting time. This  
may be used if the "new"  
input voltage has not  
changed by more than 1 LSb  
(i.e., 20.0 mV @ 5.12V) from  
the last sampled voltage (as  
stated on CHOLD).  
134  
135  
TGO Q4 to A/D clock start  
TOSC/2 §  
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 exe-  
cuted.  
TSWC Switching from convert sample time 1.5 §  
TAD  
*
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.  
§
This specification ensured by design.  
Note 1: ADRES register may be read on the following TCY cycle.  
2: See Section 8.1 for min. conditions.  
DS30561B-page 106  
1999 Microchip Technology Inc.  
PIC12C67X  
TABLE 12-9: EEPROM MEMORY BUS TIMING REQUIREMENTS - PIC12CE673/674 ONLY.  
AC Characteristics  
Standard Operating Conditions (unless otherwise specified)  
Operating Temperature 0°C TA +70°C, Vcc = 3.0V to 5.5V (commercial)  
–40°C TA +85°C, Vcc = 3.0V to 5.5V (industrial)  
–40°C TA +125°C, Vcc = 4.5V to 5.5V (extended)  
Operating Voltage VDD range is described in Section 12.1  
Parameter  
Symbol  
Min  
Max  
Units  
Conditions  
Clock frequency  
FCLK  
100  
100  
400  
kHz  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
Clock high time  
Clock low time  
THIGH  
TLOW  
TR  
4000  
4000  
600  
ns  
ns  
ns  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
4700  
4700  
1300  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
SDA and SCL rise time  
(Note 1)  
1000  
1000  
300  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
SDA and SCL fall time  
TF  
300  
ns  
ns  
(Note 1)  
START condition hold time  
THD:STA  
4000  
4000  
600  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
START condition setup time  
TSU:STA  
4700  
4700  
600  
ns  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
Data input hold time  
Data input setup time  
THD:DAT  
TSU:DAT  
0
ns  
ns  
(Note 2)  
250  
250  
100  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
STOP condition setup time  
TSU:STO  
TAA  
4000  
4000  
600  
ns  
ns  
ns  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
Output valid from clock  
(Note 2)  
3500  
3500  
900  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
Bus free time: Time the bus must  
be free before a new transmis-  
sion can start  
TBUF  
4700  
4700  
1300  
4.5V Vcc 5.5V (E Temp range)  
3.0V Vcc 4.5V  
4.5V Vcc 5.5V  
Output fall time from VIH  
minimum to VIL maximum  
TOF  
TSP  
TWC  
20+0.1  
CB  
250  
ns  
ns  
(Note 1), CB 100 pF  
Input filter spike suppression  
(SDA and SCL pins)  
50  
(Notes 1, 3)  
Write cycle time  
Endurance  
4
ms  
1M  
cycles 25°C, VCC = 5.0V, Block Mode (Note 4)  
Note 1: Not 100% tested. CB = total capacitance of one bus line in pF.  
2: As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region (min-  
imum 300 ns) of the falling edge of SCL and avoid unintended generation of START or STOP conditions.  
3: The combined TSP and VHYS specifications are due to new Schmitt Trigger inputs which provide improved  
noise spike suppression. This eliminates the need for a TI specification for standard operation.  
4: This parameter is not tested but ensured by characterization. For endurance estimates in a specific applica-  
tion, please consult the Total Endurance Model which can be obtained on Microchip’s website.  
1999 Microchip Technology Inc.  
DS30561B-page 107  
PIC12C67X  
NOTES:  
DS30561B-page 108  
1999 Microchip Technology Inc.  
PIC12C67X  
13.0 DC AND AC CHARACTERISTICS - PIC12C671/PIC12C672/PIC12LC671/  
PIC12LC672/PIC12CE673/PIC12CE674/PIC12LCE673/PIC12LCE674  
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 will operate properly only within the specified range.  
The data presented in this section is a statistical summary of data collected on units from different lots over a period of  
time. “Typical” represents the mean of the distribution while “max” or “min” represents (mean + 3σ) and (mean – 3σ)  
respectively, where σ is standard deviation.  
FIGURE 13-1: CALIBRATED INTERNAL RC  
FREQUENCY RANGE VS.  
FIGURE 13-2: CALIBRATED INTERNAL RC  
FREQUENCY RANGE VS.  
TEMPERATURE (VDD = 5.0V)  
(INTERNAL RC IS  
TEMPERATURE (VDD = 2.5V)  
(INTERNAL RC IS  
CALIBRATED TO 25°C, 5.0V)  
CALIBRATED TO 25°C, 5.0V)  
4.50  
4.40  
4.30  
4.50  
4.40  
4.30  
Max.  
4.20  
4.20  
Max.  
4.10  
4.00  
4.10  
4.00  
3.90  
3.80  
3.70  
3.60  
3.90  
3.80  
Min.  
3.70  
3.60  
3.50  
Min  
.
3.50  
-40  
0
25  
85  
125  
-40  
0
25  
85  
125  
Temperature (Deg.C)  
Temperature (Deg.C)  
1999 Microchip Technology Inc.  
DS30561B-page 109  
PIC12C67X  
TABLE 13-1: DYNAMIC IDD (TYPICAL) - WDT ENABLED, 25°C  
Oscillator  
External RC  
Frequency  
VDD = 2.5V  
VDD = 5.5V  
4 MHz  
4 MHz  
4 MHz  
32 kHz  
400 µA*  
400 µA  
400 µA  
15 µA  
900 µA*  
900 µA  
900 µA  
60 µA  
Internal RC  
XT  
LP  
*Does not include current through external R&C.  
FIGURE 13-3: WDT TIMER TIME-OUT  
FIGURE 13-4: IOH vs. VOH, VDD = 2.5 V  
PERIOD vs. VDD  
-0  
55  
50  
45  
-1  
-2  
-3  
-4  
40  
Min +125°C  
Min +85°C  
-5  
35  
Max +125°C  
-6  
Typ +25°C  
30  
Max +85°C  
-7  
-8  
25  
20  
-9  
Typ +25°C  
Max -40°C  
-10  
15  
.5 .75 1.0 1.25 1.5 1.75 2.0 2.25 2.5  
MIn –40°C  
VOH (Volts)  
10  
0
2.5  
3.5  
4.5  
5.5  
6.5  
VDD (Volts)  
DS30561B-page 110  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 13-5: IOH vs. VOH, VDD = 3.5 V  
FIGURE 13-7: IOL vs. VOL, VDD = 2.5 V  
35  
0
30  
-5  
Max -40°C  
Typ +25°C  
Min +125°C  
25  
20  
-10  
Min +85°C  
Typ +25°C  
-15  
15  
10  
Max -40°C  
Min +85°C  
-20  
Min +125°C  
-25  
1.5  
2.0  
2.5  
3.5  
3.0  
5
0
VOH (Volts)  
0
0.25  
0.5  
0.75  
1.0  
FIGURE 13-6: IOH vs. VOH, VDD = 5.5 V  
VOL (Volts)  
0
FIGURE 13-8: IOL vs. VOL, VDD = 3.5 V  
-5  
-10  
-15  
-20  
45  
Max -40°C  
40  
35  
30  
25  
-25  
-30  
Typ +25°C  
-35  
-40  
20  
15  
3.5  
4.0  
4.5  
5.0  
5.5  
Min +85°C  
VOH (Volts)  
Min +125°C  
10  
0
0
0.25  
0.5  
0.75  
1.0  
VOL (Volts)  
1999 Microchip Technology Inc.  
DS30561B-page 111  
PIC12C67X  
FIGURE 13-9: IOL vs. VOL, VDD = 5.5 V  
FIGURE 13-10: VTH (INPUT THRESHOLD  
VOLTAGE) OF GPIO PINS  
vs. VDD  
55  
1.8  
Max -40°C  
50  
45  
40  
Max (-40 to 125)  
1.6  
1.4  
Typ (25)  
1.2  
35  
30  
Typ +25°C  
Min (-40 to 125)  
1.0  
0.8  
0.6  
0
25  
20  
15  
Min +85°C  
2.5  
3.5  
4.5  
VDD (Volts)  
5.5  
Min +125°C  
10  
0
0
0.25  
0.5  
0.75  
1.0  
VOL (Volts)  
DS30561B-page 112  
1999 Microchip Technology Inc.  
PIC12C67X  
FIGURE 13-11: VIL, VIH OF NMCLR AND T0CKI vs. VDD  
3.5  
VIH Max (-40 to 125)  
VIH Typ (25)  
3.0  
2.5  
VIH Min (-40 to 125)  
2.0  
1.5  
VIL Max (-40 to 125)  
VIL Typ (25)  
VIL Min (-40 to 125)  
1.0  
0.5  
2.5  
3.5  
4.5  
VDD (Volts)  
5.5  
1999 Microchip Technology Inc.  
DS30561B-page 113  
PIC12C67X  
NOTES:  
DS30561B-page 114  
1999 Microchip Technology Inc.  
PIC12C67X  
14.0 PACKAGING INFORMATION  
14.1  
Package Marking Information  
8-Lead PDIP (300 mil)  
Example  
12CE674  
MMMMMMMM  
XXXXXCDE  
04/PSAZ  
AABB  
9925  
8-Lead SOIC (208 mil)  
Example  
MMMMMMM  
XXXXXXX  
AABBCDE  
12C671  
04I/SM  
9924SAZ  
Example  
8-Lead Windowed Ceramic Side Brazed (300 mil)  
JW  
MM  
CE674  
MMMMMM  
Legend: MM...M Microchip part number information  
XX...X Customer specific information*  
AA  
BB  
C
Year code (last 2 digits of calendar year)  
Week code (week of January 1 is week ‘01’)  
Facility code of the plant at which wafer is manufactured  
O = Outside Vendor  
C = 5” Line  
S = 6” Line  
H = 8” Line  
D
E
Mask revision number  
Assembly code of the plant or country of origin in which  
part was assembled  
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 OTP marking consists of Microchip part number, year code, week code, facility code, mask  
rev#, and assembly code. For OTP 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.  
1999 Microchip Technology Inc.  
DS30561B-page 115  
PIC12C67X  
8-Lead Plastic Dual In-line (P) – 300 mil (PDIP)  
E1  
D
2
n
1
α
E
A2  
A
L
c
A1  
β
B1  
B
p
eB  
Units  
INCHES*  
NOM  
MILLIMETERS  
Dimension Limits  
MIN  
MAX  
MIN  
NOM  
8
MAX  
n
p
Number of Pins  
Pitch  
8
.100  
.155  
.130  
2.54  
Top to Seating Plane  
A
.140  
.170  
3.56  
2.92  
3.94  
3.30  
4.32  
Molded Package Thickness  
Base to Seating Plane  
Shoulder to Shoulder Width  
Molded Package Width  
Overall Length  
A2  
A1  
E
.115  
.015  
.300  
.240  
.360  
.125  
.008  
.045  
.014  
.310  
5
.145  
3.68  
0.38  
7.62  
6.10  
9.14  
3.18  
0.20  
1.14  
0.36  
7.87  
5
.313  
.250  
.373  
.130  
.012  
.058  
.018  
.370  
10  
.325  
.260  
.385  
.135  
.015  
.070  
.022  
.430  
15  
7.94  
6.35  
9.46  
3.30  
0.29  
1.46  
0.46  
9.40  
10  
8.26  
6.60  
9.78  
3.43  
0.38  
1.78  
0.56  
10.92  
15  
E1  
D
Tip to Seating Plane  
Lead Thickness  
L
c
Upper Lead Width  
B1  
B
Lower Lead Width  
Overall Row Spacing  
Mold Draft Angle Top  
Mold Draft Angle Bottom  
*Controlling Parameter  
Notes:  
eB  
α
β
5
10  
15  
5
10  
15  
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed  
.010” (0.254mm) per side.  
JEDEC Equivalent: MS-001  
Drawing No. C04-018  
DS30561B-page 116  
1999 Microchip Technology Inc.  
PIC12C67X  
8-Lead Plastic Small Outline (SM) – Medium, 208 mil (SOIC)  
E
E1  
p
D
2
n
1
B
α
c
A2  
A
φ
A1  
L
β
Units  
INCHES*  
NOM  
MILLIMETERS  
NOM  
Dimension Limits  
MIN  
MAX  
MIN  
MAX  
n
p
Number of Pins  
Pitch  
8
8
1.27  
1.97  
1.88  
0.13  
7.95  
5.28  
5.21  
0.64  
4
.050  
.075  
.074  
.005  
.313  
.208  
.205  
.025  
4
Overall Height  
A
.070  
.080  
1.78  
2.03  
Molded Package Thickness  
Standoff  
A2  
A1  
E
.069  
.002  
.300  
.078  
.010  
.325  
.212  
.210  
.030  
8
1.75  
0.05  
7.62  
5.11  
5.13  
0.51  
0
1.98  
0.25  
8.26  
5.38  
5.33  
0.76  
8
Overall Width  
Molded Package Width  
Overall Length  
E1  
D
.201  
.202  
.020  
0
Foot Length  
L
φ
Foot Angle  
c
Lead Thickness  
Lead Width  
.008  
.014  
0
.009  
.017  
12  
.010  
.020  
15  
0.20  
0.36  
0
0.23  
0.43  
12  
0.25  
0.51  
15  
B
α
Mold Draft Angle Top  
Mold Draft Angle Bottom  
*Controlling Parameter  
Notes:  
β
0
12  
15  
0
12  
15  
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed  
.010” (0.254mm) per side.  
Drawing No. C04-056  
1999 Microchip Technology Inc.  
DS30561B-page 117  
PIC12C67X  
8-Lead Ceramic Side Brazed Dual In-line with Window (JW) – 300 mil  
E1  
W
T
D
2
1
n
U
A
A2  
L
A1  
c
B1  
p
eB  
B
Units  
INCHES*  
NOM  
MILLIMETERS  
Dimension Limits  
MIN  
MAX  
MIN  
NOM  
8
MAX  
n
p
Number of Pins  
Pitch  
8
.100  
.165  
.123  
.035  
.290  
.520  
.140  
.010  
.055  
.018  
.310  
.166  
.450  
.270  
2.54  
Top to Seating Plane  
A
.145  
.103  
.025  
.280  
.510  
.130  
.008  
.050  
.016  
.296  
.161  
.440  
.260  
.185  
3.68  
2.62  
4.19  
3.12  
0.89  
7.37  
13.21  
3.56  
0.25  
1.40  
0.46  
7.87  
4.22  
11.43  
6.86  
4.70  
Top of Body to Seating Plane  
Standoff  
A2  
A1  
E1  
D
.143  
.045  
.300  
.530  
.150  
.012  
.060  
.020  
.324  
.171  
.460  
.280  
3.63  
1.14  
7.62  
13.46  
3.81  
0.30  
1.52  
0.51  
8.23  
4.34  
11.68  
7.11  
0.64  
7.11  
12.95  
3.30  
0.20  
1.27  
0.41  
7.52  
4.09  
11.18  
6.60  
Package Width  
Overall Length  
Tip to Seating Plane  
Lead Thickness  
Upper Lead Width  
Lower Lead Width  
Overall Row Spacing  
Window Diameter  
Lid Length  
L
c
B1  
B
eB  
W
T
Lid Width  
U
*Controlling Parameter  
JEDC Equivalent: MS-015  
Drawing No. C04-083  
DS30561B-page 118  
1999 Microchip Technology Inc.  
PIC12C67X  
APPENDIX A:COMPATIBILITY  
APPENDIX B:CODE FOR  
ACCESSING EEPROM  
DATA MEMORY  
To convert code written for PIC16C5X to PIC12C67X,  
the user should take the following steps:  
1. Remove any program memory page select  
Please refer to our web site at www.microchip.com for  
code availability.  
operations (PA2, PA1, PA0 bits) for CALL, GOTO.  
2. Revisit any computed jump operations (write to  
PC or add to PC, etc.) to make sure page bits  
are set properly under the new scheme.  
3. Eliminate any data memory page switching.  
Redefine data variables to reallocate them.  
4. Verify all writes to STATUS, OPTION, and FSR  
registers since these have changed.  
5. Change reset vector to 0000h.  
1999 Microchip Technology Inc.  
DS30561B-page 119  
PIC12C67X  
NOTES:  
DS30561B-page 120  
1999 Microchip Technology Inc.  
PIC12C67X  
INDEX  
C
C bit .................................................................................... 15  
CAL0 bit.............................................................................. 21  
CAL1 bit.............................................................................. 21  
CAL2 bit.............................................................................. 21  
CAL3 bit.............................................................................. 21  
CALFST bit......................................................................... 21  
CALL Instruction ................................................................. 74  
CALSLW bit ........................................................................ 21  
Carry bit ................................................................................ 7  
Clocking Scheme................................................................ 10  
CLRF Instruction................................................................. 74  
CLRW Instruction................................................................ 74  
CLRWDT Instruction........................................................... 75  
Code Examples  
Changing Prescaler (Timer0 to WDT) ........................ 43  
Changing Prescaler (WDT to Timer0) ........................ 43  
Indirect Addressing..................................................... 23  
Code Protection............................................................ 53, 67  
COMF Instruction................................................................ 75  
Computed GOTO................................................................ 22  
Configuration Bits ............................................................... 53  
A
A/D  
Accuracy/Error ............................................................ 51  
ADCON0 Register....................................................... 45  
ADIF bit....................................................................... 47  
Analog Input Model Block Diagram............................. 48  
Analog-to-Digital Converter......................................... 45  
Configuring Analog Port Pins...................................... 49  
Configuring the Interrupt ............................................. 47  
Configuring the Module............................................... 47  
Connection Considerations......................................... 51  
Conversion Clock........................................................ 49  
Conversions................................................................ 50  
Converter Characteristics ......................................... 105  
Delays......................................................................... 48  
Effects of a Reset........................................................ 51  
Equations.................................................................... 48  
Flowchart of A/D Operation......................................... 52  
GO/DONE bit .............................................................. 47  
Internal Sampling Switch (Rss) Impedence................ 48  
Operation During Sleep .............................................. 51  
Sampling Requirements.............................................. 48  
Sampling Time............................................................ 48  
Source Impedence...................................................... 48  
Time Delays................................................................ 48  
Transfer Function........................................................ 51  
Absolute Maximum Ratings ................................................ 89  
ADDLW Instruction ............................................................. 72  
ADDWF Instruction ............................................................. 72  
ADIE bit............................................................................... 18  
ADIF bit............................................................................... 19  
ADRES Register ..................................................... 13, 45, 47  
ALU ....................................................................................... 7  
ANDLW Instruction ............................................................. 72  
ANDWF Instruction ............................................................. 72  
Application Notes  
D
DC and AC Characteristics............................................... 109  
DC bit.................................................................................. 15  
DC Characteristics  
PIC12C671/672, PIC12CE673/674............................ 92  
PIC12LC671/672, PIC12LCE673/674........................ 94  
DECF Instruction ................................................................ 75  
DECFSZ Instruction............................................................ 75  
Development Support..................................................... 3, 83  
Digit Carry bit........................................................................ 7  
Direct Addressing ............................................................... 23  
E
EEPROM Peripheral Operation.......................................... 33  
Electrical Characteristics - PIC12C67X .............................. 89  
Errata.................................................................................... 2  
External Brown-out Protection Circuit................................. 61  
External Power-on Reset Circuit......................................... 61  
AN546......................................................................... 45  
AN556......................................................................... 22  
Architecture  
F
Harvard ......................................................................... 7  
Overview....................................................................... 7  
von Neumann................................................................ 7  
Assembler  
Family of Devices ................................................................. 4  
Features ............................................................................... 1  
FSR Register.......................................................... 13, 14, 23  
MPASM Assembler..................................................... 83  
G
B
General Description.............................................................. 3  
GIE bit................................................................................. 62  
GOTO Instruction................................................................ 76  
GPIF bit .............................................................................. 64  
GPIO............................................................................. 25, 59  
GPIO Register .................................................................... 13  
GPPU bit............................................................................. 16  
BCF Instruction ................................................................... 73  
Bit Manipulation .................................................................. 70  
Block Diagrams  
Analog Input Model..................................................... 48  
On-Chip Reset Circuit................................................. 57  
Timer0......................................................................... 39  
Timer0/WDT Prescaler ............................................... 42  
Watchdog Timer.......................................................... 65  
BSF Instruction ................................................................... 73  
BTFSC Instruction............................................................... 73  
BTFSS Instruction............................................................... 74  
1999 Microchip Technology Inc.  
DS30561B-page 121  
PIC12C67X  
I
K
I/O Interfacing......................................................................25  
I/O Ports..............................................................................25  
I/O Programming Considerations........................................31  
ID Locations ........................................................................53  
INCF Instruction ..................................................................76  
INCFSZ Instruction..............................................................76  
In-Circuit Serial Programming....................................... 53, 67  
INDF Register ............................................................... 14, 23  
Indirect Addressing .............................................................23  
Initialization Conditions for All Registers.............................59  
Instruction Cycle..................................................................10  
Instruction Flow/Pipelining ..................................................10  
Instruction Format ...............................................................69  
Instruction Set  
KeeLoq Evaluation and Programming Tools ................... 86  
L
Loading of PC..................................................................... 22  
M
MCLR............................................................................ 56, 59  
Memory  
Data Memory .............................................................. 11  
Program Memory........................................................ 11  
Register File Map - PIC12CE67X............................... 12  
MOVF Instruction................................................................ 77  
MOVLW Instruction............................................................. 77  
MOVWF Instruction ............................................................ 77  
MPLAB Integrated Development Environment Software.... 83  
ADDLW .......................................................................72  
ADDWF.......................................................................72  
ANDLW .......................................................................72  
ANDWF.......................................................................72  
BCF.............................................................................73  
BSF.............................................................................73  
BTFSC ........................................................................73  
BTFSS ........................................................................74  
CALL ...........................................................................74  
CLRF...........................................................................74  
CLRW .........................................................................74  
CLRWDT.....................................................................75  
COMF .........................................................................75  
DECF ..........................................................................75  
DECFSZ......................................................................75  
GOTO .........................................................................76  
INCF............................................................................76  
INCFSZ.......................................................................76  
IORLW ........................................................................76  
IORWF ........................................................................77  
MOVF..........................................................................77  
MOVLW ......................................................................77  
MOVWF ......................................................................77  
NOP ............................................................................78  
OPTION ......................................................................78  
RETFIE .......................................................................78  
RETLW .......................................................................78  
RETURN .....................................................................79  
RLF .............................................................................79  
RRF.............................................................................79  
SLEEP ........................................................................79  
SUBLW .......................................................................80  
SUBWF.......................................................................80  
SWAPF .......................................................................81  
TRIS............................................................................81  
XORLW.......................................................................81  
XORWF.......................................................................81  
Section ........................................................................69  
INTCON Register................................................................17  
INTEDG bit..........................................................................16  
Internal Sampling Switch (Rss) Impedence ........................48  
Interrupts.............................................................................53  
A/D..............................................................................62  
GP2/INT ......................................................................62  
GPIO Port ...................................................................62  
Section ........................................................................62  
TMR0 ..........................................................................64  
TMR0 Overflow ...........................................................62  
IORLW Instruction...............................................................76  
IORWF Instruction...............................................................77  
IRP bit .................................................................................15  
N
NOP Instruction .................................................................. 78  
O
Opcode ............................................................................... 69  
OPTION Instruction ............................................................ 78  
OPTION Register................................................................ 16  
Orthogonal............................................................................ 7  
OSC selection..................................................................... 53  
OSCCAL Register............................................................... 21  
Oscillator  
EXTRC ....................................................................... 58  
HS............................................................................... 58  
INTRC......................................................................... 58  
LP ............................................................................... 58  
XT ............................................................................... 58  
Oscillator Configurations..................................................... 54  
Oscillator Types  
EXTRC ....................................................................... 54  
HS............................................................................... 54  
INTRC......................................................................... 54  
LP ............................................................................... 54  
XT ............................................................................... 54  
P
Package Marking Information........................................... 115  
Packaging Information...................................................... 115  
Paging, Program Memory................................................... 22  
PCL..................................................................................... 70  
PCL Register .......................................................... 13, 14, 22  
PCLATH.............................................................................. 59  
PCLATH Register ................................................... 13, 14, 22  
PCON Register............................................................. 20, 58  
PD bit............................................................................ 15, 56  
PICDEM-1 Low-Cost PICmicro Demo Board ..................... 85  
PICDEM-2 Low-Cost PIC16CXX Demo Board................... 85  
PICDEM-3 Low-Cost PIC16CXXX Demo Board ................ 85  
PICSTART Plus Entry Level Development System......... 85  
PIE1 Register...................................................................... 18  
Pinout Description - PIC12CE67X........................................ 9  
PIR1 Register ..................................................................... 19  
POP .................................................................................... 22  
POR.................................................................................... 58  
Oscillator Start-up Timer (OST)............................ 53, 58  
Power Control Register (PCON)................................. 58  
Power-on Reset (POR)................................... 53, 58, 59  
Power-up Timer (PWRT)...................................... 53, 58  
Power-Up-Timer (PWRT) ........................................... 58  
Time-out Sequence .................................................... 58  
Time-out Sequence on Power-up............................... 60  
TO............................................................................... 56  
Power.................................................................................. 56  
DS30561B-page 122  
1999 Microchip Technology Inc.  
PIC12C67X  
Power-down Mode (SLEEP)............................................... 66  
Prescaler, Switching Between Timer0 and WDT ................ 43  
PRO MATE II Universal Programmer .............................. 85  
Program Branches................................................................ 7  
Program Memory  
Paging......................................................................... 22  
Program Verification ........................................................... 67  
PS0 bit ................................................................................ 16  
PS1 bit ................................................................................ 16  
PS2 bit ................................................................................ 16  
PSA bit ................................................................................ 16  
PUSH .................................................................................. 22  
T
T0CS bit.............................................................................. 16  
TAD ..................................................................................... 49  
Timer0  
RTCC.......................................................................... 59  
Timers  
Timer0  
Block Diagram.................................................... 39  
External Clock .................................................... 41  
External Clock Timing......................................... 41  
Increment Delay ................................................. 41  
Interrupt .............................................................. 39  
Interrupt Timing .................................................. 40  
Prescaler ............................................................ 42  
Prescaler Block Diagram.................................... 42  
Section ............................................................... 39  
Switching Prescaler Assignment ........................ 43  
Synchronization.................................................. 41  
T0CKI ................................................................. 41  
T0IF .................................................................... 64  
Timing................................................................. 39  
TMR0 Interrupt ................................................... 64  
Timing Diagrams  
A/D Conversion ........................................................ 106  
CLKOUT and I/O ...................................................... 102  
External Clock Timing............................................... 100  
Time-out Sequence .................................................... 60  
Timer0 ........................................................................ 39  
Timer0 Interrupt Timing .............................................. 40  
Timer0 with External Clock......................................... 41  
Wake-up from Sleep via Interrupt............................... 67  
TO bit.................................................................................. 15  
TOSE bit............................................................................. 16  
TRIS Instruction.................................................................. 81  
TRIS Register ......................................................... 14, 25, 31  
Two’s Complement............................................................... 7  
R
RC Oscillator....................................................................... 55  
Read Modify Write .............................................................. 31  
Read-Modify-Write .............................................................. 31  
Register File........................................................................ 11  
Registers  
Map  
PIC12C67X......................................................... 12  
Reset Conditions......................................................... 59  
Reset............................................................................. 53, 56  
Reset Conditions for Special Registers .............................. 59  
RETFIE Instruction.............................................................. 78  
RETLW Instruction.............................................................. 78  
RETURN Instruction ........................................................... 79  
RLF Instruction.................................................................... 79  
RP0 bit .......................................................................... 11, 15  
RP1 bit ................................................................................ 15  
RRF Instruction................................................................... 79  
S
SEEVAL Evaluation and Programming System............... 86  
Services  
One-Time-Programmable (OTP) .................................. 5  
Quick-Turnaround-Production (QTP)............................ 5  
Serialized Quick-Turnaround Production (SQTP)......... 5  
SFR..................................................................................... 70  
SFR As Source/Destination ................................................ 70  
SLEEP .......................................................................... 53, 56  
SLEEP Instruction............................................................... 79  
Software Simulator (MPLAB-SIM) ...................................... 84  
Special Features of the CPU .............................................. 53  
Special Function Register  
PIC12C67X................................................................. 13  
Special Function Registers ................................................. 70  
Special Function Registers, Section ................................... 12  
Stack................................................................................... 22  
Overflows.................................................................... 22  
Underflow.................................................................... 22  
STATUS Register ............................................................... 15  
SUBLW Instruction.............................................................. 80  
SUBWF Instruction ............................................................. 80  
SWAPF Instruction.............................................................. 81  
U
UV Erasable Devices............................................................ 5  
W
W Register  
ALU............................................................................... 7  
Wake-up from SLEEP......................................................... 66  
Watchdog Timer (WDT).................................... 53, 56, 59, 65  
WDT ................................................................................... 59  
Block Diagram ............................................................ 65  
Period ......................................................................... 65  
Programming Considerations..................................... 65  
Timeout....................................................................... 59  
WWW, On-Line Support ....................................................... 2  
X
XORLW Instruction............................................................. 81  
XORWF Instruction............................................................. 81  
Z
Z bit..................................................................................... 15  
Zero bit ................................................................................. 7  
1999 Microchip Technology Inc.  
DS30561B-page 123  
PIC12C67X  
NOTES:  
DS30561B-page 124  
1999 Microchip Technology Inc.  
PIC12C67X  
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1999 Microchip Technology Inc.  
DS30561B-page 125  
PIC12C67X  
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  
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Literature Number:  
DS30561B  
Device:  
PIC12C67X  
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 data sheet easy to follow? If not, why?  
4. What additions to the data sheet do you think would enhance the structure and subject?  
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DS30561B-page 126  
1999 Microchip Technology Inc.  
PIC12C67X  
PIC12C67X PRODUCT IDENTIFICATION SYSTEM  
Examples  
PART NO. -XX X /XX XXX  
Pattern:  
Special Requirements  
a)  
b)  
c)  
d)  
e)  
f)  
PIC12CE673-04/P  
Commercial Temp.,  
PDIP Package, 4 MHz,  
normal VDD limits  
Package:  
P
JW  
SM  
=
=
=
300 mil PDIP  
300 mil Windowed Ceramic Side Brazed  
208 mil SOIC  
PIC12CE673-04I/P  
Industrial Temp., PDIP  
package,4 MHz,normal  
VDD limits  
Temperature  
Range:  
-
=
=
=
0°C to +70°C  
-40°C to +85°C  
-40°C to +125°C  
I
E
Frequency  
Range:  
04  
10  
=
=
4 MHz/200 kHz  
10 MHz  
PIC12CE673-10I/P  
Industrial Temp.,  
PDIP package, 10 MHz,  
normal VDD limits  
Device  
PIC12CE673  
PIC12C671-04/P  
PIC12CE674  
Commercial Temp.,  
PDIP Package, 4 MHz,  
normal VDD limits  
PIC12LCE673  
PIC12LCE674  
PIC12C671  
PIC12C672  
PIC12C671-04I/SM  
Industrial Temp., SOIC  
package,4 MHz,normal  
VDD limits  
PIC12C671T (Tape & reel for SOIC only)  
PIC12C672T (Tape & reel for SOIC only)  
PIC12LC671  
PIC12LC672  
PIC12LC671T (Tape & reel for SOIC only)  
PIC12LC672T (Tape & reel for SOIC only)  
PIC12C671-04I/P  
Industrial Temp.,  
PDIP package, 4 MHz,  
normal VDD limits  
* JW Devices are UV erasable and can be programmed to any device configuration. JW Devices meet the electrical requirement  
of each oscillator type (including LC devices).  
Sales and Support  
Data Sheets  
Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recom-  
mended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:  
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1999 Microchip Technology Inc.  
DS30561B-page 127  
®
Note the following details of the code protection feature on PICmicro MCUs.  
The PICmicro family meets the specifications contained in the Microchip Data Sheet.  
Microchip believes that its family of PICmicro microcontrollers is one of the most secure products 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 knowl-  
edge, require using the PICmicro microcontroller in a manner outside the operating specifications contained in the data sheet.  
The person doing so may be 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 product.  
If you have any further questions about this matter, please contact the local sales office nearest to you.  
Information contained in this publication regarding device  
applications and the like is intended through suggestion only  
and may be superseded by updates. It is your responsibility to  
ensure that your application meets with your specifications.  
No representation or warranty is given and no liability is  
assumed by Microchip Technology Incorporated with respect  
to the accuracy or use of such information, or infringement of  
patents or other intellectual property rights arising from such  
use or otherwise. Use of Microchip’s products as critical com-  
ponents in life support systems is not authorized except with  
express written approval by Microchip. No licenses are con-  
veyed, implicitly or otherwise, under any intellectual property  
rights.  
Trademarks  
The Microchip name and logo, the Microchip logo, FilterLab,  
KEELOQ, microID, MPLAB, PIC, PICmicro, PICMASTER,  
PICSTART, PRO MATE, SEEVAL and The Embedded Control  
Solutions Company are registered trademarks of Microchip Tech-  
nology Incorporated in the U.S.A. and other countries.  
dsPIC, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB,  
In-Circuit Serial Programming, ICSP, ICEPIC, microPort,  
Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM,  
MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select Mode  
and Total Endurance are trademarks of Microchip Technology  
Incorporated in the U.S.A.  
Serialized Quick Turn Programming (SQTP) is a service mark  
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All other trademarks mentioned herein are property of their  
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© 2002, Microchip Technology Incorporated, Printed in the  
U.S.A., All Rights Reserved.  
Printed on recycled paper.  
Microchip received QS-9000 quality system  
certification for its worldwide headquarters,  
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Company’s quality system processes and  
procedures are QS-9000 compliant for its  
PICmicro® 8-bit MCUs, KEELOQ® code hopping  
devices, Serial EEPROMs and microperipheral  
products. In addition, Microchips quality  
system for the design and manufacture of  
development systems is ISO 9001 certified.  
2002 Microchip Technology Inc.  
M
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Tel: 630-285-0071 Fax: 630-285-0075  
Dallas  
4570 Westgrove Drive, Suite 160  
Addison, TX 75001  
Tel: 972-818-7423 Fax: 972-818-2924  
Tel: 886-2-2717-7175 Fax: 886-2-2545-0139  
EUROPE  
Denmark  
Microchip Technology Nordic ApS  
Regus Business Centre  
Lautrup hoj 1-3  
Ballerup DK-2750 Denmark  
Tel: 45 4420 9895 Fax: 45 4420 9910  
Detroit  
Tri-Atria Office Building  
32255 Northwestern Highway, Suite 190  
Farmington Hills, MI 48334  
Tel: 248-538-2250 Fax: 248-538-2260  
Kokomo  
France  
2767 S. Albright Road  
Kokomo, Indiana 46902  
Tel: 765-864-8360 Fax: 765-864-8387  
Los Angeles  
Microchip Technology SARL  
Parc d’Activite du Moulin de Massy  
43 Rue du Saule Trapu  
Batiment A - ler Etage  
91300 Massy, France  
Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79  
18201 Von Karman, Suite 1090  
Irvine, CA 92612  
Tel: 949-263-1888 Fax: 949-263-1338  
Germany  
New York  
150 Motor Parkway, Suite 202  
Hauppauge, NY 11788  
Microchip Technology GmbH  
Gustav-Heinemann Ring 125  
D-81739 Munich, Germany  
Tel: 49-89-627-144 0 Fax: 49-89-627-144-44  
Tel: 631-273-5305 Fax: 631-273-5335  
San Jose  
Hong Kong  
Italy  
Microchip Technology Inc.  
2107 North First Street, Suite 590  
San Jose, CA 95131  
Microchip Technology Hongkong Ltd.  
Unit 901-6, Tower 2, Metroplaza  
223 Hing Fong Road  
Kwai Fong, N.T., Hong Kong  
Tel: 852-2401-1200 Fax: 852-2401-3431  
Microchip Technology SRL  
Centro Direzionale Colleoni  
Palazzo Taurus 1 V. Le Colleoni 1  
20041 Agrate Brianza  
Tel: 408-436-7950 Fax: 408-436-7955  
Toronto  
Milan, Italy  
Tel: 39-039-65791-1 Fax: 39-039-6899883  
6285 Northam Drive, Suite 108  
Mississauga, Ontario L4V 1X5, Canada  
Tel: 905-673-0699 Fax: 905-673-6509  
India  
Microchip Technology Inc.  
India Liaison Office  
United Kingdom  
Arizona Microchip Technology Ltd.  
505 Eskdale Road  
Winnersh Triangle  
Wokingham  
Divyasree Chambers  
1 Floor, Wing A (A3/A4)  
No. 11, O’Shaugnessey Road  
Bangalore, 560 025, India  
Tel: 91-80-2290061 Fax: 91-80-2290062  
Berkshire, England RG41 5TU  
Tel: 44 118 921 5869 Fax: 44-118 921-5820  
01/18/02  
2002 Microchip Technology Inc.  

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