Microchip Technology Inc PIC12C508-04E-P, PIC12C508-04E-SM, PIC12C508-04I-JW, PIC12C508-04I-P, PIC12C508-04I-SM Datasheet

...

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1997 Microchip Technology Inc. DS40139B-page 1

Devices included in this Data Sheet:

PIC12C508 and PIC12C509 are 8-bit microcontrollers packaged in 8-lead packages. They are based on the Enhanced PIC16C5X family.

High-Performance RISC CPU:

• Only 33 single word instructions to learn

• All instructions are single cycle (1 µ s) except for program branches which are two-cycle

• Operating speed: DC - 4 MHz clock input

DC - 1 µ s instruction cycle

• 12-bit wide instructions

• 8-bit wide data path

• Seven special function hardware registers

• Two-level deep hardware stack

• Direct, indirect and relative addressing modes for data and instructions

• Internal 4 MHz RC oscillator with programmable calibration

• In-circuit serial programming

Peripheral Features:

• 8-bit real time clock/counter (TMR0) with 8-bit programmable prescaler

• Power-On Reset (POR)

• Device Reset Timer (DRT)

• Watchdog Timer (WDT) with its own on-chip RC oscillator for reliable operation

• Programmable code-protection

• Power saving SLEEP mode

• Wake-up from SLEEP on pin change

• Internal weak pull-ups on I/O pins

• Internal pull-up on MCLR

• Selectable oscillator options:

- INTRC: Internal 4 MHz RC oscillator

- EXTRC: External low-cost RC oscillator

- XT: Standard crystal/resonator

- LP: Power saving, low frequency crystal

Device EPROM RAM

PIC12C508 512 x 12 25 PIC12C509 1024 x 12 41

CMOS Tec hnology:

• Low power, high speed CMOS EPROM technology

• Fully static design

• Wide operating voltage range:

- Commercial: 2.5V to 5.5V

- Industrial: 2.5V to 5.5V

- Extended: 3.0V to 5.5V

• Low power consumption

- < 2 mA @ 5V, 4 MHz

- 15 µ A typical @ 3V, 32 KHz

- < 1 µ A typical standby current

Pin Diagram

PDIP, SOIC, Windowed Ceramic Side Brazed

PIC12C508

VSS GP0 GP1 GP2/T0CKI

PIC12C509

GP5/OSC1/CLKIN

GP4/OSC2

GP3/MCLR

/VPP

VDD

PIC12C5XX

8-Pin, 8-Bit CMOS Microcontroller

PIC12C5XX

DS40139B-page 2

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1997 Microchip Technology Inc.

TABLE OF CONTENTS

1.0 General Description...........................................................................................................................................3

2.0 PIC12C5XX Device Varieties ............................................................................................................................5

3.0 Architectural Overview.......................................................................................................................................7

4.0 Memory Organization ......................................................................................................................................11

5.0 I/O Port ............................................................................................................................................................19

6.0 Timer0 Module and TMR0 Register.................................................................................................................21

7.0 Special Features of the CPU...........................................................................................................................25

8.0 Instruction Set Summary .................................................................................................................................37

9.0 Development Support......................................................................................................................................49

10.0 Electrical Characteristics - PIC12C5XX...........................................................................................................53

11.0 DC and AC Characteristics - PIC12C5XX.......................................................................................................61

12.0 Packaging Information.....................................................................................................................................65

PIC12C5XX Product Identification System....................................................................................................................73

To Our Valued Customers

We constantly strive to improve the quality of all our products and documentation. We have spent an exceptional amount of time to ensure that these documents are correct. However, we realize that we may have missed a few things. If you ﬁnd any information that is missing or appears in error, please use the reader response form in the back of this data sheet to inform us. We appreciate your assistance in making this a better document.

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1997 Microchip Technology Inc. DS40139B-page 3

PIC12C5XX

1.0 GENERAL DESCRIPTION

The PIC12C5XX from Microchip Technology is a family of low-cost, high performance, 8-bit, fully static, EPROM/ROM-based CMOS microcontrollers. It employs a RISC architecture with only 33 single word/ single cycle instructions. All instructions are single cycle (1 µ s) except for program branches which take two cycles. The PIC12C5XX delivers performance an order of magnitude higher than its competitors in the same price category. The 12-bit wide instructions are highly symmetrical resulting in 2:1 code compression over other 8-bit microcontrollers in its class. The easy to use and easy to remember instruction set reduces development time signiﬁcantly.

The PIC12C5XX products are equipped with special features that reduce system cost and power requirements. The Power-On Reset (POR) and Device Reset Timer (DRT) eliminate the need for external reset circuitry. There are four oscillator conﬁgurations to choose from, including INTRC internal oscillator mode and the power-saving LP (Low Power) oscillator. Power saving SLEEP mode, Watchdog Timer and code protection features improve system cost, power and reliability.

The PIC12C5XX are available in the cost-effective One-Time-Programmable (OTP) versions which are suitable for production in any volume. The customer can take full advantage of Microchip’s price leadership in OTP microcontrollers while beneﬁting from the O TP’ s ﬂexibility .

The PIC12C5XX products are supported by a full-featured macro assembler, a software simulator, an in-circuit emulator, a ‘C’ compiler, fuzzy logic support tools, a low-cost development programmer, and a full featured programmer. All the tools are supported on IBM



PC and compatible machines.

1.1 Applications

The PIC12C5XX series ﬁts perfectly in applications ranging from personal care appliances and security systems to low-power remote transmitters/receivers. The EPROM technology makes customizing application programs (transmitter codes, appliance settings, receiver frequencies, etc.) extremely fast and convenient. The small footprint packages, for through hole or surface mounting, make this microcontroller series perfect for applications with space limitations. Low-cost, low-power, high performance, ease of use and I/O ﬂexibility make the PIC12C5XX series very versatile even in areas where no microcontroller use has been considered before (e.g., timer functions, replacement of “glue” logic and PLD’s in larger systems, coprocessor applications).

PIC12C5XX

DS40139B-page 4

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1997 Microchip Technology Inc.

TABLE 1-1: PIC12C5XX FAMILY OF DEVICES

PIC12C508

PIC12C509

Clock

Maximum Frequency of Operation (MHz)

4 4

Memory

EPROM Program Memory (x12 words)

512 1024

Data Memory (bytes) 25 41

Peripherals Timer Module(s) TMR0 TMR0

Features

Wake-up from SLEEP on pin change

Yes Yes

I/O Pins 5 5 Input Pins 1 1 Internal Pull-ups Yes Yes Voltage Range (Volts) 2.5-5.5 2.5-5.5 In-Circuit Serial

Programming

Yes Yes

Number of Instructions 33 33 Packages 8-pin DIP,

SOIC

8-pin DIP, SOIC

All PIC12C5XX devices have Power-on Reset, selectable Watchdog Timer, selectable code protect and high I/O current capability. All PIC12C5XX devices use serial programming with data pin GP1 and clock pin GP0.

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1997 Microchip Technology Inc. DS40139B-page 5

PIC12C5XX

2.0 PIC12C5XX DEVICE VARIETIES

A variety of packaging options are available. Depending on application and production requirements, the proper device option can be selected using the information in this section. When placing orders, please use the PIC12C5XX Product Identiﬁcation System at the back of this data sheet to specify the correct part number.

2.1 UV Erasab

le Devices

The UV erasable version, offered in ceramic side brazed package, is optimal for prototype development and pilot programs.

The UV erasable version can be erased and reprogrammed to any of the conﬁguration modes.

Microchip's PICSTART



PLUS and PRO MATE



programmers all support programming of the PIC12C5XX. Third party programmers also are available; ref er to the

Microchip

Third Party Guide

for a list of sources.

2.2 One-Time-Pr

ogrammable (OTP)

Devices

The availability of OTP devices is especially useful for customers who need the ﬂexibility for frequent code updates or small volume applications.

The OTP devices , pac kaged in plastic packages permit the user to program them once. In addition to the program memory, the conﬁguration bits must also be programmed.

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.

2.3 Quic

k-Turnaround-Production (QTP)

Devices

Microchip offers a QTP Programming Service for factory 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 stabilized. The devices are identical to the OTP devices b ut with all EPROM locations and fuse options already programmed by the factory. Certain code and prototype veriﬁcation procedures do apply before production shipments are av ailable . Please contact your local Microchip Technology sales ofﬁce for more details.

2.4 Serializ

ed Quick-Turnaround

Production (SQTP

) De

vices

Microchip offers a unique programming service where a few user-deﬁned locations in each device are programmed with different serial numbers. The serial numbers may be random, pseudo-random or sequential.

Serial programming allows each device to have a unique number which can serve as an entry-code, password or ID number.

PIC12C5XX

DS40139B-page 6

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1997 Microchip Technology Inc.

NOTES:

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1997 Microchip Technology Inc. DS40139B-page 7

PIC12C5XX

3.0 ARCHITECTURAL OVERVIEW

The high performance of the PIC12C5XX family can be attributed to a number of architectural features commonly found in RISC microprocessors. To begin with, the PIC12C5XX uses a Harvard architecture in which program and data are accessed on separate buses. This improves bandwidth over traditional von Neumann architecture where program and data are fetched on the same bus. Separating program and data memory further allows instructions to be sized differently than the 8-bit wide data word. Instruction opcodes are 12-bits wide making it possible to have all single word instructions. A 12-bit wide program memory access bus fetches a 12-bit instruction in a single cycle. A two-stage pipeline overlaps fetch and execution of instructions. Consequently, all instructions (33) execute in a single cycle (1 µ s @ 4MHz) except for program branches.

The PIC12C508 address 512 x 12 of program memory, the PIC12C509 addresses 1K x 12 of program memory. All program memory is internal.

The PIC12C5XX can directly or indirectly address its register ﬁles and data memory. All special function registers including the program counter are mapped in the data memory. The PIC12C5XX has a highly 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 PIC12C5XX simple yet efﬁcient. In addition, the learning curve is reduced signiﬁcantly.

The PIC12C5XX device contains an 8-bit ALU and working register. The ALU is a general purpose arithmetic unit. It performs arithmetic and Boolean functions between data in the working register and any register ﬁle.

The ALU is 8-bits wide and capable of addition, subtraction, shift and logical operations. Unless otherwise mentioned, arithmetic operations are two's complement in nature. In two-operand instructions, typically one operand is the W (working) register. The other operand is either a ﬁle register or an immediate constant. In single operand instructions, the operand is either the W register or a ﬁle register.

The W register is an 8-bit working register used for ALU operations. It is not an addressable register.

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 borr

ow and digit borrow out bit, respectively, in subtraction. See the SUBWF and ADDWF instructions for examples.

A simpliﬁed block diagram is shown in Figure 3-1, with the corresponding device pins described in Table 3-1.

PIC12C5XX

DS40139B-page 8

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1997 Microchip Technology Inc.

FIGURE 3-1: PIC12C5XX BLOCK DIAGRAM

Device Reset

Timer

Power-on

Reset

Watchdog

Timer

EPROM

Program

Memory

Data Bus

Program

Bus

Instruction reg

Program Counter

RAM

File

Registers

Direct Addr

RAM Addr

Addr MUX

Indirect

Addr

FSR reg

STATUS reg

MUX

ALU

W reg

Instruction

Decode &

Control

Timing

Generation

OSC1/CLKIN

OSC2

MCLR

VDD, VSS

Timer0

GPIO

GP4/OSC2

GP3/MCLR/Vpp

GP2/T0CKI

GP1

GP0

5-7

GP5/OSC1/CLKIN

STACK1 STACK2

512 x 12 or

25 x 8 or

1024 x 12

41 x 8

Internal RC

OSC

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1997 Microchip Technology Inc. DS40139B-page 9

PIC12C5XX

TABLE 3-1: PIC12C5XX PINOUT DESCRIPTION

Name

DIP

Pin #

SOIC

Pin #

I/O/P Type

Buffer

Type

Description

GP0 7 7 I/O TTL/ST Bi-directional I/O port/ serial programming data. Can

be software programmed for internal weak pull-up and wake-up from SLEEP on pin change. This buffer is a Schmitt Trigger input when used in serial programming mode.

GP1 6 6 I/O TTL/ST Bi-directional I/O port/ serial programming clock. Can

be software programmed for internal weak pull-up and wake-up from SLEEP on pin change. This buffer is a Schmitt Trigger input when used in serial programming

mode. GP2/T0CKI 5 5 I/O ST Bi-directional I/O port. Can be conﬁgured as T0CKI. GP3/MCLR

4 4 I TTL Input port/master clear (reset) input/programming volt-

age input. When conﬁgured as MCLR

, this pin is an

active low reset to the device. Voltage on MCLR

must not exceed V

during normal device operation. Can be software programmed for internal weak pull-up and wake-up from SLEEP on pin change. Weak pullup always on if conﬁgured as MCLR

GP4/OSC2 3 3 I/O TTL Bi-directional I/O port/oscillator crystal output. Con-

nections to crystal or resonator in crystal oscillator mode (XT and LP modes only, GPIO in other modes).

GP5/OSC1/CLKIN 2 2 I/O TTL/ST Bidirectional IO port/oscillator crystal input/external

clock source input (GPIO in Internal RC mode only, OSC1 in all other oscillator modes). TTL input when GPIO, ST input in external RC oscillator mode.

1 1 P — Positive supply for logic and I/O pins

8 8 P — Ground reference for logic and I/O pins

Legend: I = input, O = output, I/O = input/output, P = power, — = not used, TTL = TTL input, ST = Schmitt Trigger input

PIC12C5XX

DS40139B-page 10

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1997 Microchip Technology Inc.

3.1 Cloc

king Scheme/Instruction Cycle

The clock input (OSC1/CLKIN pin) is internally divided by four to generate four non-overlapping quadrature clocks namely Q1, Q2, Q3 and Q4. Internally, the program counter is incremented every Q1, and the instruction is fetched from program memory and latched into instruction register in Q4. It is decoded and executed during the following Q1 through Q4. The clocks and instruction execution ﬂow is shown in Figure 3-2 and Example 3-1.

3.2 Instruction Flo

w/Pipelining

An Instruction Cycle consists of four Q cycles (Q1, Q2, Q3 and Q4). The instruction fetch and execute are pipelined such that fetch takes one instruction cycle while decode and execute takes another instruction cycle. However, due to the pipelining, each instruction effectively executes in one cycle. If an instruction causes the program counter to change (e.g., GOTO ) then two cycles are required to complete the instruction (Example 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

EXAMPLE 3-1: INSTRUCTION PIPELINE FLOW

Q2 Q3 Q4

OSC1

Q1 Q2 Q3 Q4

PC PC+1 PC+2

Fetch INST (PC)

Execute INST (PC-1) Fetch INST (PC+1)

Execute INST (PC) Fetch INST (PC+2)

Execute INST (PC+1)

Internal

phase clock

All instructions are single cycle, except for any program branches. These take two cycles since the fetch instruction is “ﬂushed” from the pipeline while the new instruction is being fetched and then executed.

1. MOVLW 03H

Fetch 1 Execute 1

2. MOVWF GPIO

Fetch 2 Execute 2

3. CALL SUB_1

Fetch 3 Execute 3

4. BSF GPIO, BIT1

Fetch 4 Flush

Fetch SUB_1 Execute SUB_1

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1997 Microchip Technology Inc. DS40139B-page 11

PIC12C5XX

4.0 MEMORY ORGANIZATION

PIC12C5XX memory is organized into program memory and data memory. For devices with more than 512 bytes of program memory, a paging scheme is used. Program memory pages are accessed using one STATUS register bit. For the PIC12C509 with a data memory register ﬁle of more than 32 registers, a banking scheme is used. Data memory banks are accessed using the File Select Register (FSR).

4.1 Pr

ogram Memory Organization

The PIC12C508 and PIC12C509 each have a 12-bit Program Counter (PC) capable of addressing a 2K x 12 program memory space.

Only the ﬁrst 512 x 12 (0000h-01FFh) for the PIC12C508 and 1K x 12 (0000h-03FFh) for the PIC12C509 are physically implemented. Refer to Figure 4-1. Accessing a location above these boundaries will cause a wrap-around within the ﬁrst 512 x 12 space (PIC12C508) or 1K x 12 space (PIC12C509). The effective reset vector is at 000h, (see Figure 4-1). Location 01FFh (PIC12C508) or location 03FFh (PIC12C509) contains the internal clock oscillator calibration value. This value should never be overwritten.

FIGURE 4-1: PROGRAM MEMORY MAP

AND STACK FOR THE PIC12C5XX

CALL, RETLW

PC<11:0>

Stack Level 1 Stack Level 2

User Memory

Space

0000h

7FFh

01FFh 0200h

On-chip Program

Memory

Reset Vector (note 1)

Note 1: Address 0000h becomes the

effective reset vector. Location 01FFh (PIC12C508) or location 03FFh (PIC12C509) contains the MOVLW XX INTRC oscillator calibration value.

512 Word (PIC12C508)

1024 Word (PIC12C509)

03FFh 0400h

On-chip Program

Memory

PIC12C5XX

DS40139B-page 12

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1997 Microchip Technology Inc.

4.2 Data Memor

y Organization

Data memory is composed of registers, or bytes of RAM. Therefore, data memory for a device is speciﬁed by its register ﬁle. The register ﬁle is divided into two functional groups: special function registers and general purpose registers.

The special function registers include the TMR0 register, the Program Counter (PC), the Status Register, the I/O registers (ports), and the File Select Register (FSR). In addition, special purpose registers are used to control the I/O port conﬁguration and prescaler options.

The general purpose registers are used for data and control information under command of the instructions.

For the PIC12C508, the register ﬁle is composed of 7 special function registers and 25 general purpose registers (Figure 4-2).

For the PIC12C509, the register ﬁle is composed of 7 special function registers, 25 general purpose registers, and 16 general purpose registers that may be addressed using a banking scheme (Figure 4-3).

4.2.1 GENERAL PURPOSE REGISTER FILE The general purpose register ﬁle is accessed either

directly or indirectly through the ﬁle select register FSR (Section 4.7).

FIGURE 4-2: PIC12C508 REGISTER FILE

MAP

File Address

00h 01h 02h 03h 04h 05h 06h 07h

1Fh

INDF

(1)

TMR0

PCL

STATUS

FSR

OSCCAL

GPIO

General Purpose

Registers

Note 1: Not a physical register. See Section 4.7

FIGURE 4-3: PIC12C509 REGISTER FILE MAP

File Address

00h 01h 02h 03h 04h 05h 06h

07h

1Fh

INDF

(1)

TMR0

PCL

STATUS

FSR

OSCCAL

GPIO

0Fh

10h

Bank 0 Bank 1

3Fh

30h

20h

2Fh

General Purpose Registers

Addresses map back to addresses in Bank 0.

Note 1: Not a physical register. See Section 4.7

FSR<6:5> 00 01

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1997 Microchip Technology Inc. DS40139B-page 13

PIC12C5XX

4.2.2 SPECIAL FUNCTION REGISTERS The Special Function Registers (SFRs) are registers

used by the CPU and peripheral functions to control the operation of the device (Table 4-1).

The special registers can be classiﬁed into two sets. The special function registers associated with the “core” functions are described in this section. Those related to the operation of the peripheral features are described in the section for each peripheral feature.

TABLE 4-1: SPECIAL FUNCTION REGISTER (SFR) SUMMARY

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Value on

Power-On

Reset

Value on

CLR and

WDT Reset

Value on Wake-up on Pin Change

N/A TRIS I/O control registers

--11 1111 --11 1111 --11 1111

N/A OPTION

Contains control bits to conﬁgure Timer0, Timer0/WDT prescaler, wake-up on change, and weak pull-ups

1111 1111 1111 1111 1111 1111

00h INDF

Uses contents of FSR to address data memory (not a physical register)

xxxx xxxx uuuu uuuu uuuu uuuu

01h TMR0 8-bit real-time clock/counter

xxxx xxxx uuuu uuuu uuuu uuuu

02h

(1)

PCL Low order 8 bits of PC

1111 1111 1111 1111 1111 1111

03h STATUS GPWUF

—

PA0 T

O PD Z DC C 0001 1xxx 000q quuu 100q quuu

04h

FSR (12C508)

Indirect data memory address pointer

111x xxxx 111u uuuu 111u uuuu

04h

FSR (12C509)

Indirect data memory address pointer

110x xxxx 11uu uuuu 11uu uuuu

05h OSCCAL CAL7 CAL6 CAL5 CAL4 — — — — 0111 ---- uuuu ---- uuuu ---- 06h GPIO — — GP5 GP4 GP3 GP2 GP1 GP0 --xx xxxx --uu uuuu --uu uuuu Legend: Shaded boxes = unimplemented or unused, — = unimplemented, read as '0' (if applicable)

x = unknown, u = unchanged, q = see the tables in Section 7.7 for possible values.

Note 1: The upper byte of the Program Counter is not directly accessible. See Section 4.5

for an explanation of how to access these bits.

PIC12C5XX

DS40139B-page 14  1997 Microchip Technology Inc.

4.3 STATUS Register

This register contains the arithmetic status of the ALU, the RESET status, and the page preselect bit for program memories larger than 512 words.

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. Further more, the T

O and PD bits are not writable. Therefore, the result of an instruction with the STATUS register as destination may be different than intended.

For example, CLRF STATUS will clear the upper three bits and set the Z bit. This leaves the STATUS register as 000u u1uu (where u = unchanged).

It is recommended, therefore, that only BCF, BSF and MOVWF instructions be used to alter the STATUS register because these instructions do not affect the Z, DC or C bits from the STATUS register. For other instructions, which do affect STATUS bits, see Instruction Set Summary.

FIGURE 4-4: STATUS REGISTER (ADDRESS:03h)

R/W-0 R/W-0 R/W-0 R-1 R-1 R/W-x R/W-x R/W-x

GPWUF

—

PA0 TO PD Z DC C R = Readable bit

W = Writable bit

- n = Value at POR reset

bit7 6 5 4 3 2 1 bit0 bit 7: GPWUF: GPIO reset bit

1 = Reset due to wake-up from SLEEP on pin change

0 = After power up or other reset bit 6: Unimplemented bit 5: PA0: Program page preselect bits

1 = Page 1 (200h - 3FFh) - PIC12C509

0 = Page 0 (000h - 1FFh) - PIC12C508 and PIC12C509

Each page is 512 bytes.

Using the PA0 bit as a general purpose read/write bit in devices which do not use it for program

page preselect is not recommended since this may affect upward compatibility with future products. bit 4: TO: Time-out bit

1 = After power-up, CLRWDT instruction, or SLEEP instruction

0 = A WDT time-out occurred bit 3: PD: Power-down bit

1 = After power-up or by the CLRWDT instruction

0 = By execution of the SLEEP instruction bit 2: 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 bit 1: DC: Digit carry/borrow bit (for ADDWF and SUBWF instructions)

ADDWF

1 = A carry from the 4th low order bit of the result occurred

0 = A carry from the 4th low order bit of the result did not occur

SUBWF

1 = A borrow from the 4th low order bit of the result did not occur

0 = A borrow from the 4th low order bit of the result occurred bit 0: C: Carry/borrow bit (for ADDWF, SUBWF and RRF, RLF instructions)

ADDWF SUBWF RRF or RLF

1 = A carry occurred 1 = A borrow did not occur Load bit with LSB or MSB, respectively

0 = A carry did not occur 0 = A borrow occurred

 1997 Microchip Technology Inc. DS40139B-page 15

PIC12C5XX

4.4 OPTION Register

The OPTION register is a 8-bit wide, write-only register which contains various control bits to conﬁgure the Timer0/WDT prescaler and Timer0.

By executing the OPTION instruction, the contents of the W register will be transferred to the OPTION register. A RESET sets the OPTION<7:0> bits.

Note: If TRIS bit is set to ‘0’, the wake-up on

change and pull-up functions are disabled for that pin; i.e., note that TRIS overrides OPTION control of GPPU

and GPWU.

Note: If the T0CS bit is set to ‘1’, GP2 is forced to

be an input even if TRIS GP2 = ‘0’.

FIGURE 4-5: OPTION REGISTER

W-1 W-1 W-1 W-1 W-1 W-1 W-1 W-1

GPWU GPPU T0CS T0SE PSA PS2 PS1 PS0 W = Writable bit

U = Unimplemented bit

- n = Value at POR reset Reference Table 4-1 for other resets.

bit7 6 5 4 3 2 1 bit0

bit 7: GPWU

: Enable wake-up on pin change (GP0, GP1, GP3) 1 = Disabled 0 = Enabled

bit 6: GPPU: Enable weak pull-ups (GP0, GP1, GP3)

1 = Disabled 0 = Enabled

bit 5: T0CS: Timer0 clock source select bit

1 = Transition on T0CKI pin 0 = Transition on internal instruction cycle clock, Fosc/4

bit 4: T0SE: Timer0 source edge select bit

1 = Increment on high to low transition on the T0CKI pin 0 = Increment on low to high transition on the T0CKI pin

bit 3: PSA: Prescaler assignment bit

1 = Prescaler assigned to the WDT 0 = Prescaler assigned to Timer0

bit 2-0: PS2:PS0: Prescaler rate select bits

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

Bit Value Timer0 Rate WDT Rate

PIC12C5XX

DS40139B-page 16  1997 Microchip Technology Inc.

4.5 Program Counter

As a program instruction is executed, the Program Counter (PC) will contain the address of the next program instruction to be executed. The PC value is increased by one every instruction cycle, unless an instruction changes the PC.

For a GOTO instruction, bits 8:0 of the PC are provided by the GOTO instruction word. The PC Latch (PCL) is mapped to PC<7:0>. Bit 5 of the STATUS register provides page information to bit 9 of the PC (Figure 4-

6). For a CALL instruction, or any instruction where the

PCL is the destination, bits 7:0 of the PC again are provided by the instruction word. However, PC<8> does not come from the instruction word, but is always cleared (Figure 4-6).

Instructions where the PCL is the destination, or Modify PCL instructions, include MOVWF PC, ADDWF PC, and BSF PC,5.

FIGURE 4-6: LOADING OF PC

BRANCH INSTRUCTIONS PIC12C508/C509

Note: Because PC<8> is cleared in the CALL

instruction, or any Modify PCL instruction, all subroutine calls or computed jumps are limited to the ﬁrst 256 locations of any program memory page (512 words long).

PA0

STATUS

8 7 0

PCL

910

Instruction Word

7 0

GOTO Instruction

CALL or Modify PCL Instruction

PA0

STATUS

8 7 0

PCL

910

Instruction Word

7 0

Reset to ‘0’

4.5.1 EFFECTS OF RESET The Program Counter is set upon a RESET, which

means that the PC addresses the last location in the last page i.e., the oscillator calibration instruction. After executing MOVLW XX, the PC will roll over to location 00h, and begin executing user code.

The STATUS register page preselect bits are cleared upon a RESET, which means that page 0 is preselected.

Therefore, upon a RESET, a GOTO instruction will automatically cause the program to jump to page 0 until the value of the page bits is altered.

4.6 Stack

PIC12C5XX devices have a 12-bit wide hardware push/pop stack.

A CALL instruction will

push

the current value of stack 1 into stack 2 and then push the current program counter value, incremented by one, into stack level 1. If more than two sequential CALL’s are executed, only the most recent two return addresses are stored.

A RETLW instruction will

pop

the contents of stack level 1 into the program counter and then copy stack level 2 contents into level 1. If more than two sequential RETLW’s are executed, the stack will be filled with the address previously stored in level 2. Note that the W register will be loaded with the literal value speciﬁed in the instruction. This is particularly useful for the implementation of data look-up tables within the program memory.

 1997 Microchip Technology Inc. DS40139B-page 17

PIC12C5XX

4.7 Indirect Data Addressing; INDF and FSR Registers

The INDF register is not a physical register. Addressing INDF actually addresses the register whose address is contained in the FSR register (FSR is a

pointer

). This is indirect addressing.

EXAMPLE 4-1: INDIRECT ADDRESSING

• Register ﬁle 07 contains the value 10h

• Register ﬁle 08 contains the value 0Ah

• Load the value 07 into the FSR register

• A read of the INDF register will return the value

of 10h

• Increment the value of the FSR register by one

(FSR = 08)

• A read of the INDR register now will return the

value of 0Ah.

Reading INDF itself indirectly (FSR = 0) will produce 00h. Writing to the INDF register indirectly results in a no-operation (although STATUS bits may be affected).

A simple program to clear RAM locations 10h-1Fh using indirect addressing is shown in Example 4-2.

EXAMPLE 4-2: HOW TO CLEAR RAM

USING INDIRECT ADDRESSING

movlw 0x10 ;initialize pointer movwf FSR ; to RAM

NEXT clrf INDF ;clear INDF register

incf FSR,F ;inc pointer btfsc FSR,4 ;all done? goto NEXT ;NO, clear next

CONTINUE

: ;YES, continue

The FSR is a 5-bit wide register. It is used in conjunction with the INDF register to indirectly address the data memory area.

The FSR<4:0> bits are used to select data memory addresses 00h to 1Fh.

PIC12C508: Does not use banking. FSR<6:5> are unimplemented and read as '1's.

PIC12C509: Uses FSR<5>. Selects between bank 0 and bank 1. FSR<6> is unimplemented, read as '1’ .

FIGURE 4-7: DIRECT/INDIRECT ADDRESSING

Note 1: For register map detail see Section 4.2. Note 2: PIC12C509 only

bank

location select

bank select

Indirect Addressing

Direct Addressing

Data Memory

(1)

0Fh 10h

Bank 0 Bank 1

(2)

(FSR)

00 01

00h

1Fh 3Fh

(opcode) 04

(FSR)

Addresses map back to addresses in Bank 0.

PIC12C5XX

DS40139B-page 18  1997 Microchip Technology Inc.

NOTES:

 1997 Microchip Technology Inc. DS40139B-page 19

PIC12C5XX

5.0 I/O PORT

As with any other register, the I/O register can be written and read under program control. However, read instructions (e.g., 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 (GP5:GP0). Bits 7 and 6 are unimplemented and read as '0's. 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 wake-up on change. The wake-up on change and weak pull-up functions are not pin selectable. If pin 4 is conﬁgured as MCLR

, weak pullup is always on and wake-up on change for this pin is not enabled.

5.2 TRIS Register

The output driver control register is loaded with the contents of the W register by executing the TRIS f instruction. 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 GP2 which may be controlled by the option register, see Section 4.4.

The TRIS registers are “write-only” and are set (output drivers disabled) upon RESET.

Note: A read of the por ts 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.

5.3 I/O Interfacing

The equivalent circuit for an I/O port pin is shown in Figure 5-1. All port pins, except GP3 which is input only, may be used for both input and output operations. For input operations these ports are nonlatching. Any input must be present until read by an input instruction (e.g., 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.

FIGURE 5-1: EQUIVALENT CIRCUIT

FOR A SINGLE I/O PIN

Note 1: I/O pins have protection diodes to VDD and VSS.

Data Bus

WR Port

TRIS ‘f’

Data

TRIS

RD Port

VSS

VDD

I/O pin

(1)

W Reg

Latch

Reset

TABLE 5-1: SUMMARY OF PORT REGISTERS

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Value on

Power-On

Reset

Value on

MCLR and

WDT Reset

Value on Wake-up on Pin Change

N/A TRIS I/O control registers --11 1111 --11 1111 --11 1111 N/A

OPTION GPWU GPPU T0CS T0SE PSA PS2 PS1 PS0

1111 1111 1111 1111 1111 1111

03H

STATUS

GPWUF — PA0 TO PD Z DC C 0001 1xxx 000q quuu 100q quuu

06h

GPIO

— — GP5 GP4 GP3 GP2 GP1 GP0 --xx xxxx --uu uuuu --uu uuuu

Legend: Shaded cells not used by Port Registers, read as ‘0’, — = unimplemented, read as '0', x = unknown, u = unchanged,

q = see tables in Section 7.7 for possible values.

PIC12C5XX

DS40139B-page 20  1997 Microchip Technology Inc.

5.4 I/O Programming Considerations

5.4.1 BI-DIRECTIONAL I/O PORTS Some instructions operate internally as read followed

by write operations. The BCF and BSF instructions, for example, read the entire port into the CPU, execute the bit operation and re-write the result. Caution must be used when these instructions are applied to a port where one or more pins are used as input/outputs. For example, a BSF oper ation on bit5 of GPIO will cause all eight bits of GPIO to be read into the CPU, bit5 to be set and the GPIO value to be written to the output latches. If another bit of GPIO is used as a bidirectional I/O pin (say 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, overwriting the previous content. As long as the pin stays in the input mode, no problem occurs. However, if bit0 is switched into output mode later on, the content of the data latch may now be unknown.

Example 5-1 shows the effect of two sequential readmodify-write instructions (e.g., BCF, BSF, etc.) on an I/ O port.

A pin actively outputting a high or a low 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.

EXAMPLE 5-1: READ-MODIFY-WRITE

INSTRUCTIONS ON AN I/O PORT

;Initial GPIO Settings ; GPIO<5:3> Inputs ; GPIO<2:0> Outputs ; ; GPIO latch GPIO pins ; ---------- --------- BCF GPIO, 5 ;--01 -ppp --11 pppp BCF GPIO, 4 ;--10 -ppp --11 pppp MOVLW 007h ; TRIS GPIO ;--10 -ppp --11 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).

5.4.2 SUCCESSIVE OPERATIONS ON I/O PORTS

The actual write to an I/O port happens at the end of an instruction cycle, whereas for reading, the data must be valid at the beginning of the instruction cycle (Figure 5-2). Therefore, care must be exercised if a write followed by a read operation is carried out on the same I/O port. The sequence of instructions should allow the pin voltage to stabilize (load dependent) before the next instruction, which causes that ﬁle to be read into the CPU, is executed. Otherwise, the previous state of that pin may be read into the CPU rather than the new state. When in doubt, it is better to separate these instructions with a NOP or another instruction not accessing this I/O port.

FIGURE 5-2: SUCCESSIVE I/O OPERATION

PC PC + 1 PC + 2

PC + 3

Q1 Q2

Instruction

fetched

GP5:GP0

MOVWF GPIO

NOP

Port pin sampled here

NOP

MOVF GPIO,W

Instruction

executed

MOVWF GPIO

(Write to

GPIO)

NOP

MOVF GPIO,W

This example shows a write to GPIO followed by a read from GPIO.

Data setup time = (0.25 TCY – TPD) where: TCY = instruction cycle.

TPD = propagation delay

Therefore, at higher clock frequencies, a write followed by a read may be problematic.

(Read

GPIO)

Port pin written here

 1997 Microchip Technology Inc. DS40139B-page 21

PIC12C5XX

6.0 TIMER0 MODULE AND TMR0 REGISTER

The Timer0 module has the following features:

• 8-bit timer/counter register, TMR0

- Readable and writable

• 8-bit software programmable prescaler

• Internal or external clock select

- Edge select for external clock

Figure 6-1 is a simpliﬁed block diagram of the Timer0 module.

Timer mode is selected by clearing the T0CS bit (OPTION<5>). In timer mode, the Timer0 module will increment every instruction cycle (without prescaler). If TMR0 register is written, the increment is inhibited for the following two cycles (Figure 6-2 and Figure 6-3). The user can work around this by writing an adjusted value to the TMR0 register.

Counter mode is selected by setting the T0CS bit (OPTION<5>). In this mode, Timer0 will increment either on every rising or falling edge of pin T0CKI. The T0SE bit (OPTION<4>) determines the source edge. Clearing the T0SE bit selects the rising edge. Restrictions on the external clock input are discussed in detail in Section 6.1.

The prescaler may be used by either the Timer0 module or the Watchdog Timer, but not both. The prescaler assignment is controlled in software by the control bit PSA (OPTION<3>). Clearing the PSA bit will assign the prescaler to Timer0. 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 6.2 details the operation of the prescaler.

A summary of registers associated with the Timer0 module is found in Table 6-1.

FIGURE 6-1: TIMER0 BLOCK DIAGRAM

Note 1: Bits T0CS, T0SE, PSA, PS2, PS1 and PS0 are located in the OPTION register.

2: The prescaler is shared with the Watchdog Timer (Figure 6-5).

T0CS

(1)

FOSC/4

Programmable

Prescaler

(2)

Sync with

Internal

Clocks

TMR0 reg

PSout

(2 cycle delay)

PSout

Data bus

PSA

(1)

PS2, PS1, PS0

(1)

Sync

T0SE

GP2/T0CKI

PIC12C5XX

DS40139B-page 22  1997 Microchip Technology Inc.

FIGURE 6-2: TIMER0 TIMING: INTERNAL CLOCK/NO PRESCALE

FIGURE 6-3: TIMER0 TIMING: INTERNAL CLOCK/PRESCALE 1:2

TABLE 6-1: REGISTERS ASSOCIATED WITH TIMER0

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Value on

Power-On

Reset

Value on

MCLR and

WDT Reset

Value on Wake-up on Pin Change

01h TMR0 Timer0 - 8-bit real-time clock/counter xxxx xxxx uuuu uuuu

uuuu uuuu

N/A OPTION

GPWU GPPU T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

1111 1111

N/A TRIS I/O control registers --11 1111 --11 1111 --11 1111 Legend: Shaded cells not used by Timer0,

- = unimplemented, x = unknown, u = unchanged,

PC-1

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)

Instruction Fetch

Timer0

PC PC+1 PC+2 PC+3 PC+4 PC+5 PC+6

T0+1 T0+2 NT0 NT0 NT0 NT0+1 NT0+2

MOVWF TMR0

MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W

Write TMR0 executed

Read TMR0 reads NT0

Read TMR0 reads NT0 + 1

Read TMR0 reads NT0 + 2

Instruction Executed

PC-1

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)

Instruction

Fetch

Timer0

PC PC+1 PC+2 PC+3 PC+4 PC+5 PC+6

T0 NT0+1

MOVWF TMR0

MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W

Write TMR0 executed

Read TMR0 reads NT0

Read TMR0 reads NT0 + 1

T0+1

NT0

Instruction Execute

 1997 Microchip Technology Inc. DS40139B-page 23

PIC12C5XX

6.1 Using Timer0 with an External Clock

When an external clock input is used for Timer0, it must meet certain requirements. The external clock requirement is due to internal phase clock (T

OSC)

synchronization. Also, there is a delay in the actual incrementing of Timer0 after synchronization.

6.1.1 EXTERNAL CLOCK SYNCHRONIZATION When no prescaler is used, the external clock input is

the same as the prescaler output. 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 6-4). Therefore, it is necessary for T0CKI to be high for at least 2T

OSC (and a small RC delay of 20 ns)

and low for at least 2T

OSC (and a small RC delay of

20 ns). Refer to the electrical speciﬁcation of the desired device.

When a prescaler is used, the external clock input is divided by the asynchronous ripple counter-type prescaler so that the prescaler output is symmetrical. For the external clock to meet the sampling requirement, the ripple counter must be taken into account. Therefore, it is necessary for T0CKI to have a period of at least 4T

OSC (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 minimum pulse width requirement of 10 ns. Refer to parameters 40, 41 and 42 in the electrical speciﬁcation of the desired device.

6.1.2 TIMER0 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 module is actually incremented. Figure 6-4 shows the delay from the external clock edge to the timer incrementing.

6.1.3 OPTION REGISTER EFFECT ON GP2 TRIS If the option register is set to read TIMER0 from the pin,

the port is forced to an input regardless of the TRIS register setting.

FIGURE 6-4: TIMER0 TIMING WITH EXTERNAL CLOCK

Increment Timer0 (Q4)

External Clock Input or

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Timer0

T0 T0 + 1 T0 + 2

Small pulse misses sampling

External Clock/Prescaler Output After Sampling

(3)

Note 1:

2: 3:

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. External clock if no prescaler selected, Prescaler output otherwise. The arrows indicate the points in time where sampling occurs.

Prescaler Output (2)

(1)

PIC12C5XX

DS40139B-page 24  1997 Microchip Technology Inc.

6.2 Prescaler

An 8-bit counter is available as a prescaler for the Timer0 module, or as a postscaler for the Watchdog Timer (WDT), respectively (Section 7.6). For simplicity, this counter is being referred to as “prescaler” throughout this data sheet. Note that the prescaler may be used by either the Timer0 module or the WDT, but not both. Thus, a prescaler assignment for the Timer0 module means that there is no prescaler for the WDT, and vice-versa.

The PSA and PS2:PS0 bits (OPTION<3:0>) determine prescaler assignment and prescale ratio.

When assigned to the Timer0 module, all instructions writing to the TMR0 register (e.g., 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 WDT. The prescaler is neither readable nor writable. On a RESET, the prescaler contains all '0's.

6.2.1 SWITCHING PRESCALER ASSIGNMENT The prescaler assignment is fully under software control

(i.e., it can be changed “on the ﬂy” during program execution). To avoid an unintended device RESET, the following instruction sequence (Example 6-1) must be executed when changing the prescaler assignment from Timer0 to the WDT.

EXAMPLE 6-1: CHANGING PRESCALER

(TIMER0→WDT)

1.CLRWDT ;Clear WDT

2.CLRF TMR0 ;Clear TMR0 & Prescaler

3.MOVLW '00xx1111’b; ;These 3 lines (5, 6, 7)

4.OPTION ; are required only if ; desired

5.CLRWDT ;PS<2:0> are 000 or 001

6.MOVLW '00xx1xxx’b ;Set Postscaler to

7.OPTION ; desired WDT rate

To change prescaler from the WDT to the Timer0 module, use the sequence shown in Example 6-2. This sequence must be used even if the WDT is disabled. A CLRWDT instruction should be executed before switching the prescaler.

EXAMPLE 6-2: CHANGING PRESCALER

(WDT→TIMER0)

CLRWDT ;Clear WDT and

;prescaler

MOVLW 'xxxx0xxx' ;Select TMR0, new

;prescale value and ;clock source

OPTION

FIGURE 6-5: BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER

TCY ( = Fosc/4)

Sync

Cycles

TMR0 reg

8-bit Prescaler

8 - to - 1MUX

MUX

Watchdog

Timer

PSA

WDT

Time-Out

PS2:PS0

Note: T0CS, T0SE, PSA, PS2:PS0 are bits in the OPTION register.

PSA

WDT Enable bit

Data Bus

PSA

T0CS

M U

U X

T0SE

GP2/T0CKI

 1997 Microchip Technology Inc. DS40139B-page 25

PIC12C5XX

7.0 SPECIAL FEATURES OF THE CPU

What sets a microcontroller apart from other processors are special circuits to deal with the needs of real-time applications. The PIC12C5XX family of microcontrollers has a host of such features intended to maximize system reliability, minimize cost through elimination of external components, provide power saving operating modes and offer code protection. These features are:

• Oscillator selection

• Reset

- Power-On Reset (POR)

- Device Reset Timer (DRT)

- Wake-up from SLEEP on pin change

• Watchdog Timer (WDT)

• SLEEP

• Code protection

• ID locations

• In-circuit Serial Programming

The PIC12C5XX has a Watchdog Timer which can be shut off only through conﬁguration bit WDTE. It runs off of its own RC oscillator for added reliability. If using XT or LP selectable oscillator options, there is always an 18 ms (nominal) delay provided by the Device Reset Timer (DRT), intended to keep the chip in reset until the crystal oscillator is stable. If using INTRC or EXTRC there is an 18 ms delay only on V

DD power-up.

With this timer on-chip, most applications need no external reset circuitry.

The SLEEP mode is designed to offer a very low current power-down mode. The user can wake-up from SLEEP through a change on input pins or through a Watchdog Timer time-out. Several oscillator options are also made available to allow the part to ﬁt the application, including an internal 4 MHz oscillator. The EXTRC oscillator option saves system cost while the LP crystal option saves power. A set of conﬁguration bits are used to select various options.

7.1 Conﬁguration Bits

The PIC12C5XX conﬁguration word consists of 5 bits. Conﬁguration bits can be programmed to select various device conﬁgurations. Two bits are for the selection of the oscillator type, one bit is the Watchdog Timer enable bit, and one bit is the MCLR

enable bit.

One bit is the code protection bit (Figure 7-1).

FIGURE 7-1: CONFIGURATION WORD FOR PIC12C508 OR PIC12C509

— — — — — — — MCLRE CP WDTE FOSC1 FOSC0 Register: CONFIG

Address

(1)

: FFFh

bit11 10 9 8 7 6 5 4 3 2 1 bit0 bit 11-5: Unimplemented bit 4: MCLRE: MCLR

enable bit. 1 = MCLR pin enabled 0 = MCLR tied to VDD, (Internally)

bit 3: CP: Code protection bit.

1 = Code protection off 0 = Code protection on

bit 2: WDTE: Watchdog timer enable bit

1 = WDT enabled 0 = WDT disabled

bit 1-0: FOSC1:FOSC0: Oscillator selection bits

11 = EXTRC - external RC oscillator 10 = INTRC - internal RC oscillator 01 = XT oscillator 00 = LP oscillator

Note 1: Refer to the PIC12C5XX Programming Speciﬁcations to determine how to access the

conﬁguration word. This register is not user addressable during device operation.

PIC12C5XX

DS40139B-page 26  1997 Microchip Technology Inc.

7.2 Oscillator Conﬁgurations

7.2.1 OSCILLATOR TYPES The PIC12C5XX can be operated in four different

oscillator modes. The user can program two conﬁguration bits (FOSC1:FOSC0) to select one of these four modes:

• LP: Low Power Crystal

• XT: Crystal/Resonator

• INTRC: Internal 4 MHz Oscillator

• EXTRC: External Resistor/Capacitor

7.2.2 CRYSTAL OSCILLATOR / CERAMIC RESONATORS

In XT or LP modes, a crystal or ceramic resonator is connected to the GP5/OSC1/CLKIN and GP4/OSC2 pins to establish oscillation (Figure 7-2). The PIC12C5XX oscillator design requires the use of a parallel cut crystal. Use of a series cut crystal may give a frequency out of the crystal manufacturers speciﬁcations. When in XT or LP modes, the device can have an external clock source drive the GP5/ OSC1/CLKIN pin (Figure 7-3).

FIGURE 7-2: CRYSTAL OPERATION (OR

CERAMIC RESONATOR) (XT OR LP OSC CONFIGURATION)

FIGURE 7-3: EXTERNAL CLOCK INPUT

OPERATION (XT OR LP OSC CONFIGURATION)

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 crystal chosen

(approx. value = 10 MΩ).

(1)

XTAL

OSC2

OSC1

(3)

SLEEP

To internal

logic

(2)

PIC12C5XX

Clock from ext. system

OSC1

OSC2

PIC12C5XX

Open

TABLE 7-1: CAPACITOR SELECTION

FOR CERAMIC RESONATORS

- PIC12C5XX

TABLE 7-2: CAPACITOR SELECTION

FOR CRYSTAL OSCILLATOR

- PIC12C5XX

Osc

Type

Resonator

Freq

Cap. RangeC1Cap. Range

XT 4.0 MHz 30 pF 30 pF

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.

Osc

Type

Resonator

Freq

Cap.Range

Cap. Range

LP 32 kHz

(1)

15 pF 15 pF

XT 200 kHz

1 MHz 4 MHz

47-68 pF

15 pF 15 pF

47-68 pF

15 pF 15 pF

Note 1: For V

DD > 4.5V, C1 = C2 ≈ 30 pF is

recommended. These values are for design guidance only. Rs may be required in XT mode to avoid overdriving crystals with low drive level speciﬁcation. Since each crystal has its own characteristics, the user should consult the crystal manufacturer for appropriate values of external components.

 1997 Microchip Technology Inc. DS40139B-page 27

PIC12C5XX

7.2.3 EXTERNAL CRYSTAL OSCILLATOR CIRCUIT

Either a prepackaged oscillator or a simple oscillator circuit with TTL gates can be used as an external crystal oscillator circuit. Prepackaged 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 7-4 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 kΩ resistor 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 7-4: EXTERNAL PARALLEL

RESONANT CRYSTAL OSCILLATOR CIRCUIT

Figure 7-5 shows a series resonant oscillator circuit. This circuit is also designed to use the fundamental frequency of the crystal. The inverter performs a 180degree phase shift in a series resonant oscillator circuit. The 330 Ω resistors provide the negative feedback to bias the inverters in their linear region.

FIGURE 7-5: EXTERNAL SERIES

RESONANT CRYSTAL OSCILLATOR CIRCUIT

20 pF

+5V

20 pF

10k

4.7k

10k

74AS04

XTAL

10k

74AS04

PIC12C5XX

CLKIN

To Other Devices

330

74AS04

PIC12C5XX

CLKIN

To Other Devices

XTAL

330

74AS04

0.1 µF

7.2.4 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.

Figure 7-6 shows how the R/C combination is connected to the PIC12C5XX. For Rext values below

2.2 kΩ, the oscillator operation may become unstable, or stop completely. For very high Rext values (e.g., 1 MΩ) the oscillator becomes sensitive to noise, humidity and leakage. Thus, we recommend keeping Rext between 3 kΩ and 100 kΩ.

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.

The Electrical Speciﬁcations sections show RC frequency variation from part to part due to normal process variation. 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).

Also, see the Electrical Speciﬁcations sections for variation of oscillator frequency due to V

DD for given

Rext/Cext values as well as frequency variation due to operating temperature for given R, C, and V

DD values.

FIGURE 7-6: EXTERNAL RC OSCILLATOR

MODE

VDD

Rext

Cext V

OSC1

Internal clock

PIC12C5XX

DS40139B-page 28  1997 Microchip Technology Inc.

7.2.5 INTERNAL 4 MHz RC OSCILLATOR The internal RC oscillator provides a ﬁxed 4 MHz (nom-

inal) system clock. In addition, a calibration instruction is programmed into

the top of memory which contains the calibration value for the internal RC oscillator. This v alue is prog r ammed as a MOVLW XX instruction where XX is the calibration value, and is placed at the reset vector. This will load the W register with the calibration value upon reset and the PC will then roll over to the users program at address 0x000. The user then has the option of writing the value to the OSCCAL Register (05h) or ignoring it.

OSCCAL, when written to with the calibration value, will “trim” the internal oscillator to remove process variation from the oscillator frequency. The upper 4 bits of the register are used to allow for future, longer bit length calibration schemes. Writing a larger value in this location yields a higher clock speed.

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.

7.3 RESET

The device differentiates between various kinds of reset:

a) Power on reset (POR) b) MCLR

reset during normal operation

c) MCLR

reset during SLEEP d) WDT time-out reset during normal operation e) WDT time-out reset during SLEEP f) Wake-up from SLEEP on pin change

Some registers are not reset in any way; they are unknown on POR and unchanged in any other reset. Most other registers are reset to “reset state” on po weron reset (POR), on MCLR

, WDT or wake-up on pin change reset during normal operation. They are not affected by a WDT reset during SLEEP or MCLR

reset during SLEEP, since these resets are viewed as resumption of normal operation. The exceptions to this are T

O, PD, and GPWUF bits. They are set or cleared differently in different reset situations. These bits are used in software to determine the nature of reset. See Table 7-3 for a full description of reset states of all registers.

TABLE 7-3: RESET CONDITIONS FOR REGISTERS

MCLR

Reset

WDT time-out

Wake-up on Pin Change

W — qqqq xxxx (1) qqqq uuuu (1)

INDF 00h xxxx xxxx uuuu uuuu

TMR0 01h xxxx xxxx uuuu uuuu

PC 02h 1111 1111 1111 1111

STATUS 03h 0001 1xxx ?00? ?uuu (2) FSR (12C508) 04h 111x xxxx 111u uuuu FSR (12C509) 04h 110x xxxx 11uu uuuu

OSCCAL 05h 0111 ---- uuuu ----

GPIO 06h --xx xxxx --uu uuuu

OPTION — 1111 1111 1111 1111

TRIS — --11 1111 --11 1111

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, ? = value depends on condition.

Note 1: Bits <7:4> of W register contain oscillator calibration values due to MOVLW XX instruction at top of memory. Note 2: See Table 7-7 for reset value for speciﬁc conditions

 1997 Microchip Technology Inc. DS40139B-page 29

PIC12C5XX

TABLE 7-4: RESET CONDITION FOR SPECIAL REGISTERS

STATUS Addr: 03h PCL Addr: 02h

Power on reset 0001 1xxx 1111 1111 MCLR

reset during normal operation 000u uuuu 1111 1111

MCLR

reset during SLEEP 0001 0uuuu 1111 1111 WDT reset during SLEEP 0000 0uuu 1111 1111 WDT reset normal operation 0000 1uuu 1111 1111 Wake-up from SLEEP on pin change 1001 0uuu 1111 1111 Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’.

7.3.1 MCLR ENABLE This conﬁguration bit when unprogrammed (left in the

‘1’ state) enables the external MCLR

function. When

programmed, the MCLR

function is tied to the internal

DD, and the pin is assigned to be a GPIO. See

Figure 7-7.

FIGURE 7-7: MCLR SELECT

7.4 P

ower-On Reset (POR)

The PIC12C5XX family incorporates on-chip PowerOn Reset (POR) circuitry which provides an internal chip reset for most power-up situations.

A Power-on Reset pulse is generated on-chip when V

DD rise is detected (in the range of 1.5V - 2.1V). To

take advantage of the internal POR, program the GP3/ MCLR

/VPP pin as MCLR and tie directly to VDD or program the pin as GP3. An internal weak pull-up resistor is implemented using a transistor. Refer to Table 10-6 for the pull-up resistor ranges. This will eliminate external RC components usually needed to create a Pow eron Reset. A maximum rise time for V

DD is speciﬁed.

See Electrical Speciﬁcations for details. 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 parameters are met.

A simpliﬁed block diagram of the on-chip Power-On Reset circuit is shown in Figure 7-8.

GP3/MCLR/VPP

MCLRE

INTERNAL MCLR

WEAK PULL-UP

The Power-On Reset circuit and the Device Reset Timer (Section 7.5) circuit are closely related. On power-up, the reset latch is set and the DRT is reset. The DRT timer begins counting once it detects MCLR to be high. After the time-out period, which is typically 18 ms, it will reset the reset latch and thus end the onchip reset signal.

A power-up example where MCLR

is held low is shown

in Figure 7-9. V

DD is allowed to rise and stabilize

before bringing MCLR

high. The chip will actually

come out of reset T

DRT msec after MCLR goes high.

In Figure 7-10, the on-chip Power-On Reset feature is being used (MCLR

and VDD are tied together or the pin

is programmed to be GP3.). The V

DD is stable before

the start-up timer times out and there is no problem in getting a proper reset. However, Figure 7-11 depicts a problem situation where V

DD rises too slowly. The time

between when the DRT senses that MCLR

is high and

when M

CLR (and VDD) actually reach their full value, is too long. In this situation, when the start-up timer times out, V

DD has not reached the VDD (min) value and the

chip is, therefore, not guaranteed to function correctly. For such situations, we recommend that external RC circuits be used to achieve longer POR delay times (Figure 7-10).

For additional information refer to Application Notes “

Power-Up Considerations”

- AN522 and “

Power-up

Trouble Shooting

” - AN607.

Note: When the device starts normal operation

(exits the reset condition), device operating parameters (voltage, frequency, temperature, etc.) must be meet to ensure operation. If these conditions are not met, the device must be held in reset until the operating conditions are met.

PIC12C5XX

DS40139B-page 30  1997 Microchip Technology Inc.

FIGURE 7-8: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT

S Q

VDD

GP3/MCLR/VPP

Power-Up

Detect

On-Chip

DRT OSC

POR (Power-On Reset)

WDT Time-out

RESET

CHIP RESET

8-bit Asynch

Ripple Counter

(Start-Up Timer)

MCLRE

SLEEP

Pin Change

Wake-up on pin change

 1997 Microchip Technology Inc. DS40139B-page 31

PIC12C5XX

FIGURE 7-9: TIME-OUT SEQUENCE ON POWER-UP (MCLR PULLED LOW)

FIGURE 7-10: TIME-OUT SEQUENCE ON POWER-UP (MCLR

TIED TO VDD): FAST VDD RISE TIME

FIGURE 7-11: TIME-OUT SEQUENCE ON POWER-UP (MCLR

TIED TO VDD): SLOW VDD RISE TIME

VDD

MCLR

INTERNAL POR

DRT TIME-OUT

INTERNAL RESET

TDRT

VDD

MCLR

INTERNAL POR

DRT TIME-OUT

INTERNAL RESET

TDRT

VDD

MCLR

INTERNAL POR

DRT TIME-OUT

INTERNAL RESET

TDRT

When VDD rises slowly, the TDRT time-out expires long before VDD has reached its ﬁnal value. In this example, the chip will reset properly if, and only if, V1 ≥ VDD min.

PIC12C5XX

DS40139B-page 32  1997 Microchip Technology Inc.

7.5 Device Reset Timer (DRT)

In the PIC12C5XX, the DRT runs any time the device is powered up. DRT runs from RESET and varies based on oscillator selection (see Table 7-5.)

The Device Reset Timer (DRT) provides a ﬁxed 18 ms nominal time-out on reset. The DRT operates on an internal RC oscillator. The processor is kept in RESET as long as the DRT is active. The DRT delay allows V

DD to rise above VDD min., and for the oscillator to

stabilize. Oscillator circuits based on crystals or ceramic

resonators require a certain time after power-up to establish a stable oscillation. The on-chip DRT keeps the device in a RESET condition for approximately 18 ms after MCLR

has reached a logic high (VIHMCLR)

level. Thus, programming GP3/MCLR

/VPP as MCLR and using an external RC network connected to the MCLR

input is not required in most cases, allowing for savings in cost-sensitive and/or space restricted applications, as well as allowing the use of the GP3/ MCLR

/VPP pin as a general purpose input. The Device Reset time delay will vary from chip to chip

due to V

DD, temperature, and process variation. See

AC parameters for details. The DRT will also be triggered upon a W atchdog Timer

time-out (only in XT and LP modes). This is particularly impor tant for applications using the WDT to wake from SLEEP mode automatically.

7.6 Watchdog Timer (WDT)

The Watchdog Timer (WDT) is a free running on-chip RC oscillator which does not require any external components. This RC oscillator is separate from the external RC oscillator of the GP5/OSC1/CLKIN pin and the internal 4 MHz oscillator. That means that the WDT will run even if the main processor clock has been stopped, for example, by execution of a SLEEP instruction. During normal operation or SLEEP, a WDT reset or wake-up reset generates a device RESET.

The T

O bit (STATUS<4>) will be cleared upon a

Watchdog Timer reset. The WDT can be permanently disabled by

programming the conﬁguration bit WDTE as a '0' (Section 7.1). Refer to the PIC12C5XX Programming Speciﬁcations to determine how to access the conﬁguration word.

TABLE 7-5: DRT (DEVICE RESET TIMER PERIOD)

Oscillator Conﬁguration POR Reset Subsequent Resets

IntRC & ExtRC 18 ms (typical) 300 µs (typical) XT & LP 18 ms (typical) 18 ms (typical)

 1997 Microchip Technology Inc. DS40139B-page 33

PIC12C5XX

7.6.1 WDT PERIOD The WDT has a nominal time-out period of 18 ms,

(with no prescaler). If a longer time-out period is 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, a time-out period of a nominal 2.3 seconds can be realized. These periods vary with temperature, V

DD and part-to-

part process variations (see DC specs). Under worst case conditions (V

DD = Min., Temperature

= Max., max. WDT prescaler), it may take several seconds before a WDT time-out occurs.

7.6.2 WDT PROGRAMMING CONSIDERATIONS The CLRWDT instruction clears the WDT and the

postscaler, if assigned to the WDT, and prevents it from timing out and generating a device RESET.

The SLEEP instruction resets the WDT and the postscaler, if assigned to the WDT. This gives the maximum SLEEP time before a WDT wake-up reset.

FIGURE 7-12: WATCHDOG TIMER BLOCK DIAGRAM

TABLE 7-6: SUMMARY OF REGISTERS ASSOCIATED WITH THE WATCHDOG TIMER

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Value on

Power-On

Reset

Value on

MCLR and

WDT Reset

Value on Wake-up on Pin Change

N/A OPTION GPWU GPPU T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

1111 1111

Legend: Shaded boxes = Not used by Watchdog Timer, — = unimplemented, read as '0', u = unchanged

From Timer0 Clock Source (Figure 6-5)

To Timer0 (Figure 6-4)

Postscaler

WDT Enable

Conﬁguration Bit

PSA

WDT

Time-out

PS2:PS0

PSA

MUX

8 - to - 1 MUX

Postscaler

M U X

Watchdog

Timer

Note: T0CS, T0SE, PSA, PS2:PS0

are bits in the OPTION register.

PIC12C5XX

DS40139B-page 34  1997 Microchip Technology Inc.

7.7 Time-Out Sequence, Power Down, and Wake-up from SLEEP Status Bits (TO/PD/GPWUF)

The TO, PD, and GPWUF bits in the STATUS register can be tested to determine if a RESET condition has been caused by a power-up condition, a MCLR

Watchdog Timer (WDT) reset, or a MCLR

or WDT

reset.

These STATUS bits are only affected by events listed in Table 7-8.

Table 7-4 lists the reset conditions for the special function registers, while Table 7-3 lists the reset conditions for all the registers.

TABLE 7-7: TO/PD/GPWUF STATUS

AFTER RESET

GPWUF TO PD RESET caused by

0 0 0

WDT wake-up from SLEEP

0 0 1

WDT time-out (not from SLEEP)

0 1 0

MCLR wake-up from SLEEP

0 1 1

Power-up

0 u u

MCLR not during SLEEP

1 1 0

Wake-up from SLEEP on pin change

Legend: Legend: u = unchanged

Note 1: The TO, PD, and GPWUF bits main-

tain their status (u) until a reset occurs. A low-pulse on the MCLR input does not change the TO, PD, and GPWUF status bits.

TABLE 7-8: EVENTS AFFECTING TO/PD

STATUS BITS

Event GPWUF TO PD Remarks

Power-up

0 1 1

WDT Time-out

0 0 u

No effect on PD

SLEEP instruction

u 1 0

CLRWDT instruction

u 1 1

Wake-up from SLEEP on pin change

1 1 0

Legend: u = unchanged A WDT time-out will occur regardless of the status of the TO bit. A SLEEP instruction will be executed, regardless of the status of the PD bit. Table 7-7 reﬂects the status of TO and PD after the corresponding event.

7.8 Reset on Brown-Out

A brown-out is a condition where device power (VDD) dips below its minimum value, b ut not to z ero, and then recovers. The device should be reset in the event of a brown-out.

To reset PIC12C5XX devices when a brown-out occurs, external brown-out protection circuits may be built, as shown in Figure 7-13 and Figure 7-14.

FIGURE 7-13: BROWN-OUT PROTECTION

CIRCUIT 1

FIGURE 7-14: BROWN-OUT PROTECTION

CIRCUIT 2

This circuit will activate reset when VDD goes below Vz +

0.7V (where Vz = Zener voltage). *Refer to Figure 7-7 and Table 10-6 for internal weak pull-

up on MCLR.

33k

10k

40k*

MCLR

PIC12C5XX

VDD

This brown-out circuit is less expensive, although less accurate. Transistor Q1 turns off when V

is below a certain level such that:

*Refer to Figure 7-7 and Table 10-6 for internal weak pull-up on MCLR.

VDD •

R1 + R2

= 0.7V

40k

VDD

MCLR

PIC12C5XX

VDD

 1997 Microchip Technology Inc. DS40139B-page 35

PIC12C5XX

7.9 Power-Down Mode (SLEEP)

A device may be powered down (SLEEP) and later powered up (Wake-up from SLEEP).

7.9.1 SLEEP The Power-Down mode is entered by executing a

SLEEP instruction. If enabled, the Watchdog Timer will be cleared but

keeps running, the T

O bit (STATUS<4>) is set, the PD bit (STATUS<3>) is cleared and the oscillator driver is turned off. The I/O ports maintain the status they had before the SLEEP instruction was executed (driving high, driving low, or hi-impedance).

It should be noted that a RESET generated by a WDT time-out does not drive the MCLR

pin low.

For lowest current consumption while powered down, the T0CKI input should be at V

DD or VSS and the GP3/

MCLR

/VPP pin must be at a logic high level (VIHMC) if

MCLR

is enabled.

7.9.2 WAKE-UP FROM SLEEP The device can wake-up from SLEEP through one of

the following events:

1. An external reset input on GP3/MCLR

/VPP pin,

when conﬁgured as MCLR

2. A Watchdog Timer time-out reset (if WDT was

enabled).

3. A change on input pin GP0, GP1, or GP3/

MCLR

/VPP when wake-up on change is

enabled.

These events cause a device reset. The T

O, PD, and GPWUF bits can be used to determine the cause of device reset. The T

O bit is cleared if a WDT time-out

occurred (and caused wake-up). The PD

bit, which is set on power-up, is cleared when SLEEP is invoked. The GPWUF bit indicates a change in state while in SLEEP at pins GP0, GP1, or GP3 (since the last time there was a ﬁle or bit operation on GP port).

The WDT is cleared when the device wakes from sleep, regardless of the wake-up source.

Caution: Right before entering SLEEP, read the

input pins. When in SLEEP, wake up occurs when the values at the pins change from the state they were in at the last reading. If a wake-up on change occurs and the pins are not read before reentering SLEEP, a wake up will occur immediately even if no pins change while in SLEEP mode.

7.10 Program Veriﬁcation/Code Protection

If the code protection bit has not been programmed, the on-chip program memory can be read out for veriﬁcation purposes.

The ﬁrst 64 locations can be read regardless of the code protection bit setting.

7.11 ID Locations

Four memory locations are designated as ID locations where the user can store checksum or other codeidentiﬁcation numbers. These locations are not accessible during normal execution but are readable and writable during program/verify.

Use only the lower 4 bits of the ID locations and always program the upper 8 bits as '0's.

PIC12C5XX

DS40139B-page 36  1997 Microchip Technology Inc.

7.12 In-Circuit Serial Programming

The PIC12C5XX microcontrollers can be serially programmed while in the end application circuit. This is simply done with two lines for clock and data, and three other lines for power, ground, and the programming voltage. This allows customers to manufacture boards with unprogrammed devices, and then program the microcontroller just before shipping the product. This also allows the most recent ﬁrmware or a custom ﬁrmware to be programmed.

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 becomes the programming clock and GP0 becomes the programming data. Both GP1 and GP0 are Schmitt Trigger inputs in this mode.

After reset, a 6-bit command is then supplied to the device. Depending on the command, 14-bits of program 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 PIC12C5XX Programming Speciﬁcations.

A typical in-circuit serial programming connection is shown in Figure 7-15.

FIGURE 7-15: TYPICAL IN-CIRCUIT SERIAL

PROGRAMMING CONNECTION

External Connector Signals

To Normal Connections

PIC12C5XX

VSS MCLR/VPP

GP1

GP0

+5V

VPP

CLK

Data I/O

VDD

 1997 Microchip Technology Inc. DS40139B-page 37

PIC12C5XX

8.0 INSTRUCTION SET SUMMARY

Each PIC12C5XX instruction is a 12-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 PIC12C5XX instruction set summary in Table 8-2 groups the instructions into byte-oriented, bit-oriented, and literal and control operations. Table 8-1 shows the opcode ﬁeld descriptions.

For byte-oriented instructions, 'f' represents a ﬁle register designator and 'd' represents a destination designator. The ﬁle register designator is used to specify which one of the 32 file registers is to be used by the instruction.

The destination designator speciﬁes where the result of the operation is to be placed. If 'd' is '0', the result is placed in the W register. If 'd' is '1', the result is placed in the ﬁle register speciﬁed in the instruction.

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.

For literal and control operations, 'k' represents an 8 or 9-bit constant or literal value.

TABLE 8-1: OPCODE FIELD

DESCRIPTIONS

Field Description

f Register ﬁle address (0x00 to 0x7F) W Working register (accumulator) b Bit address within an 8-bit ﬁle register k Literal ﬁeld, constant data or label

Don't care location (= 0 or 1) The assembler will generate code with x = 0. It is the recommended form of use for compatibility with all Microchip software tools.

Destination select;

d = 0 (store result in W) d = 1 (store result in ﬁle register 'f')

Default is d = 1

label Label name

TOS Top of Stack

PC Program Counter

WDT Watchdog Timer Counter

Time-Out bit

PD Power-Down bit

dest

Destination, either the W register or the speciﬁed register ﬁle location

[ ]

Options

( )

Contents

→

Assigned to

< >

∈

In the set of

talics

User deﬁned term (font is courier)

All instructions are executed within a single instruction cycle, unless a conditional test is true or the program counter is changed as a result of an instruction. In this case, the execution takes two instruction cycles. One instruction cycle consists of four oscillator periods. Thus, for an oscillator frequency of 4 MHz, the normal instruction execution time is 1 µs. If a conditional test is true or the program counter is changed as a result of an instruction, the instruction execution time is 2 µs.

Figure 8-1 shows the three general formats that the instructions can have. All examples in the ﬁgure use the following format to represent a hexadecimal number:

0xhhh

where 'h' signiﬁes a hexadecimal digit.

FIGURE 8-1: GENERAL FORMAT FOR

INSTRUCTIONS

Byte-oriented ﬁle register operations

11 6 5 4 0

d = 0 for destination W

OPCODE d f (FILE #)

d = 1 for destination f f = 5-bit ﬁle register address

Bit-oriented ﬁle register operations

11 8 7 5 4 0

OPCODE b (BIT #) f (FILE #)

b = 3-bit bit address f = 5-bit ﬁle register address

Literal and control operations (except GOTO)

11 8 7 0

OPCODE k (literal)

k = 8-bit immediate value

Literal and control operations - GOTO instruction

11 9 8 0

OPCODE k (literal)

k = 9-bit immediate value

PIC12C5XX

DS40139B-page 38  1997 Microchip Technology Inc.

TABLE 8-2: INSTRUCTION SET SUMMARY

Mnemonic,

Operands Description Cycles

12-Bit Opcode

Status

Affected NotesMSb LSb

ADDWF ANDWF CLRF CLRW COMF DECF DECFSZ INCF INCFSZ IORWF MOVF MOVWF NOP RLF RRF SUBWF SWAPF XORWF

f,d f,d f – f, d f, d f, d f, d f, d f, d f, d f – f, d f, d f, d f, d f, d

Add W and f AND W with f Clear f Clear W Complement f Decrement f Decrement f, Skip if 0 Increment f Increment f, Skip if 0 Inclusive OR W with f Move f Move W to f No Operation Rotate left f through Carry Rotate right f through Carry Subtract W from f Swap f Exclusive OR W with f

1 1 1 1 1 1

1(2)

1 1 1 1 1 1 1 1 1

0001 0001 0000 0000 0010 0000 0010 0010 0011 0001 0010 0000 0000 0011 0011 0000 0011 0001

11df 01df 011f 0100 01df 11df 11df 10df 11df 00df 00df 001f 0000 01df 00df 10df 10df 10df

ffff ffff ffff 0000 ffff ffff ffff ffff ffff ffff ffff ffff 0000 ffff ffff ffff ffff ffff

C,DC,Z

Z Z Z Z Z

None

Z None None

C C

C,DC,Z

None

1,2,4

2,4

2,4 2,4 2,4 2,4 2,4 2,4 1,4

2,4 2,4

1,2,4

2,4 2,4

BIT-ORIENTED FILE REGISTER OPERATIONS BCF

BSF BTFSC BTFSS

f, b f, b f, b f, b

Bit Clear f Bit Set f Bit Test f, Skip if Clear Bit Test f, Skip if Set

1 1 (2) 1 (2)

0100 0101 0110 0111

bbbf bbbf bbbf bbbf

ffff ffff ffff ffff

None None None None

2,4 2,4

LITERAL AND CONTROL OPERATIONS ANDLW

CALL CLRWDT GOTO IORLW MOVLW OPTION RETLW SLEEP TRIS XORLW

k k k k k k – k – f k

AND literal with W Call subroutine Clear Watchdog Timer Unconditional branch Inclusive OR Literal with W Move Literal to W Load OPTION register Return, place Literal in W Go into standby mode Load TRIS register Exclusive OR Literal to W

1 2 1 2 1 1 1 2 1 1 1

1110 1001 0000 101k 1101 1100 0000 1000 0000 0000 1111

kkkk kkkk 0000 kkkk kkkk kkkk 0000 kkkk 0000 0000 kkkk

kkkk kkkk 0100 kkkk kkkk kkkk 0010 kkkk 0011 0fff kkkk

None

O, PD

None

Z None None None

O, PD

None

Note 1: The 9th bit of the program counter will be forced to a '0' by any instruction that writes to the PC except f or GOTO.

(Section 4.5)

2: When an I/O register is modiﬁed as a function of itself (e.g. MOVF GPIO, 1), the value used will be that value

present on the pins themselves. For example, if the data latch is '1' f or a pin conﬁgured as input and is driv en low by an external device , the data will be written back with a '0'.

3: The instruction TRIS f, where f = 6 causes the contents of the W register to be written to the tristate latches of

GPIO. A '1' forces the pin to a hi-impedance state and disables the output buff ers .

4: If this instruction is executed on the TMR0 register (and, where applicable , d = 1), the prescaler will be cleared

(if assigned to TMR0).

 1997 Microchip Technology Inc. DS40139B-page 39

PIC12C5XX

ADDWF Add W and f

Syntax: [

label

] ADDWF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (W) + (f) → (dest) Status Affected: C, DC, Z Encoding:

0001 11df ffff

Description:

Add the contents of the W register and

in the W register . If 'd' is '1' the result is

stored back in register 'f'

. Words: 1 Cycles: 1 Example:

ADDWF FSR, 0

Before Instruction

W = 0x17 FSR = 0xC2

After Instruction

W = 0xD9 FSR = 0xC2

ANDLW And literal with W

Syntax: [

label

] ANDLW k Operands: 0 ≤ k ≤ 255 Operation: (W).AND. (k) → (W) Status Affected: Z Encoding:

1110 kkkk kkkk

Description:

The contents of the W register are AND’ed with the eight-bit literal 'k'. The result is placed in the W register

. Words: 1 Cycles: 1 Example:

ANDLW 0x5F

Before Instruction

W = 0xA3

After Instruction

W = 0x03

ANDWF AND W with f

Syntax: [

label

] ANDWF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (W) .AND. (f) → (dest) Status Affected: Z Encoding:

0001 01df ffff

Description:

The contents of the W register are

AND’ed 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: 1 Cycles: 1 Example:

ANDWF FSR, 1

Before Instruction

W = 0x17 FSR = 0xC2

After Instruction

W = 0x17 FSR = 0x02

BCF Bit Clear f

Syntax: [

label

] BCF f,b

Operands: 0 ≤ f ≤ 31

0 ≤ b ≤ 7 Operation: 0 → (f<b>) Status Affected: None Encoding:

0100 bbbf ffff

Description:

Bit 'b' in register 'f' is cleared.

Words: 1 Cycles: 1 Example:

BCF FLAG_REG, 7

Before Instruction

FLAG_REG = 0xC7

After Instruction

FLAG_REG = 0x47

PIC12C5XX

DS40139B-page 40  1997 Microchip Technology Inc.

BSF Bit Set f

Syntax: [

label

] BSF f,b

Operands: 0 ≤ f ≤ 31

0 ≤ b ≤ 7 Operation: 1 → (f<b>) Status Affected: None Encoding:

0101 bbbf ffff

Description:

Bit 'b' in register 'f' is set.

Words: 1 Cycles: 1 Example:

BSF FLAG_REG, 7

Before Instruction

FLAG_REG = 0x0A

After Instruction

FLAG_REG = 0x8A

BTFSC Bit Test f, Skip if Clear

Syntax: [

label

] BTFSC f,b

Operands: 0 ≤ f ≤ 31

0 ≤ b ≤ 7 Operation: skip if (f<b>) = 0 Status Affected: None Encoding: 0110

bbbf ffff

Description:

If bit 'b' in register 'f' is 0 then the next

instruction is skipped.

If bit 'b' is 0 then the next instruction

fetched during the current instruction

execution is discarded, and an NOP is

executed instead, making this a 2 cycle

instruction.

Words: 1 Cycles: 1(2) Example:

HERE

FALSE

TRUE

BTFSC GOTO

•

FLAG,1 PROCESS_CODE

Before Instruction

PC = address (HERE)

After Instruction

if FLAG<1> = 0, PC = address (TRUE); if FLAG<1> = 1, PC = address(FALSE)

BTFSS Bit Test f, Skip if Set

Syntax: [

label

] BTFSS f,b

Operands: 0 ≤ f ≤ 31

0 ≤ b < 7 Operation: skip if (f<b>) = 1 Status Affected: None Encoding:

0111 bbbf ffff

Description:

If bit 'b' in register 'f' is '1' then the next

instruction is skipped.

If bit 'b' is '1', then the next instruction

fetched during the current instruction

execution, is discarded and an NOP is

executed instead, making this a 2 cycle

instruction.

Words: 1 Cycles: 1(2) Example:

HERE BTFSS FLAG,1

FALSE GOTO PROCESS_CODE

TRUE •

•

Before Instruction

PC = address (HERE)

After Instruction

If FLAG<1> = 0, PC = address (FALSE); if FLAG<1> = 1, PC = address (TRUE)

 1997 Microchip Technology Inc. DS40139B-page 41

PIC12C5XX

CALL Subroutine Call

Syntax: [

label

] CALL k Operands: 0 ≤ k ≤ 255 Operation: (PC) + 1→ Top of Stack;

k → PC<7:0>; (STATUS<6:5>) → PC<10:9>;

0 → PC<8> Status Affected: None Encoding:

1001 kkkk kkkk

Description:

Subroutine call. First, return address

(PC+1) is pushed onto the stack. The

eight bit immediate address is loaded

into PC bits <7:0>. The upper bits

PC<10:9> are loaded from STA-

TUS<6:5>, PC<8> is cleared. CALL is a

two cycle instruction.

Words: 1 Cycles: 2 Example:

HERE CALL THERE

Before Instruction

PC = address (HERE)

After Instruction

PC = address (THERE) TOS= address (HERE + 1)

CLRF Clear f

Syntax: [

label

] CLRF f Operands: 0 ≤ f ≤ 31 Operation: 00h → (f);

1 → Z Status Affected: Z Encoding:

0000 011f ffff

Description:

The contents of register 'f' are cleared

and the Z bit is set.

Words: 1 Cycles: 1 Example:

CLRF FLAG_REG

Before Instruction

FLAG_REG = 0x5A

After Instruction

FLAG_REG = 0x00 Z = 1

CLRW Clear W

Syntax: [

label

] CLRW Operands: None Operation: 00h → (W);

1 → Z Status Affected: Z Encoding:

0000 0100 0000

Description:

The W register is cleared. Zero bit (Z)

is set.

Words: 1 Cycles: 1 Example:

CLRW

Before Instruction

W = 0x5A

After Instruction

W = 0x00 Z = 1

CLRWDT Clear Watchdog Timer

Syntax: [

label

] CLRWDT Operands: None Operation: 00h → WDT;

0 → WDT prescaler (if assigned); 1 → T

1 → PD Status Affected: TO, PD Encoding:

0000 0000 0100

Description:

The CLRWDT instruction resets the

WDT. It also resets the prescaler, if the

prescaler is assigned to the WDT and

not Timer0. Status bits TO and PD are

set.

Words: 1 Cycles: 1 Example:

CLRWDT

Before Instruction

WDT counter = ?

After Instruction

WDT counter = 0x00 WDT prescale = 0 TO = 1 PD = 1

PIC12C5XX

DS40139B-page 42  1997 Microchip Technology Inc.

COMF Complement f

Syntax: [

label

] COMF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1]

Operation: (f

) → (dest) Status Affected: Z Encoding:

0010 01df ffff

Description:

The contents of register 'f' are complemented. 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: 1 Cycles: 1 Example:

COMF REG1,0

Before Instruction

REG1 = 0x13

After Instruction

REG1 = 0x13 W = 0xEC

DECF Decrement f

Syntax: [

label

] DECF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (f) – 1 → (dest) Status Affected: Z Encoding:

0000 11df ffff

Description:

Decrement register 'f'. If 'd' is 0 the

result is stored in the W register . If 'd' is

1 the result is stored back in register 'f'.

Words: 1 Cycles: 1 Example:

DECF CNT,

Before Instruction

CNT = 0x01 Z = 0

After Instruction

CNT = 0x00 Z = 1

DECFSZ Decrement f, Skip if 0

Syntax: [

label

] DECFSZ f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (f) – 1 → d; skip if result = 0 Status Affected: None Encoding:

0010 11df ffff

Description:

The contents of register 'f' are decre-

mented. If 'd' is 0 the result is placed in

the W register. If 'd' is 1 the result is

placed back in register 'f'.

If the result is 0, the next instruction,

which is already fetched, is discarded

and an NOP is executed instead mak-

ing it a two cycle instruction.

Words: 1 Cycles: 1(2) Example:

HERE DECFSZ CNT, 1

GOTO LOOP

CONTINUE •

•

Before Instruction

PC = address (HERE)

After Instruction

CNT = CNT - 1; if CNT = 0, PC = address (CONTINUE); if CNT ≠ 0, PC = address (HERE+1)

GOTO Unconditional Branch

Syntax: [

label

] GOTO k Operands: 0 ≤ k ≤ 511 Operation: k → PC<8:0>;

STATUS<6:5> → PC<10:9> Status Affected: None Encoding:

101k kkkk kkkk

Description:

GOTO is an unconditional branch. The

9-bit immediate value is loaded into PC

bits <8:0>. The upper bits of PC are

loaded from STATUS<6:5>. GOTO is a

two cycle instruction.

Words: 1 Cycles: 2 Example:

GOTO THERE

After Instruction

PC = address (THERE)

 1997 Microchip Technology Inc. DS40139B-page 43

PIC12C5XX

INCF Increment f

Syntax: [

label

] INCF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (f) + 1 → (dest) Status Affected: Z Encoding:

0010 10df ffff

Description:

The contents of register 'f' are incre-

mented. If 'd' is 0 the result is placed in

the W register. If 'd' is 1 the result is

placed back in register 'f'.

Words: 1 Cycles: 1 Example:

INCF CNT,

Before Instruction

CNT = 0xFF Z = 0

After Instruction

CNT = 0x00 Z = 1

INCFSZ Increment f, Skip if 0

Syntax: [

label

] INCFSZ f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (f) + 1 → (dest), skip if result = 0 Status Affected: None Encoding:

0011 11df ffff

Description:

The contents of register 'f' are incre-

mented. If 'd' is 0 the result is placed in

the W register. If 'd' is 1 the result is

placed back in register 'f'.

If the result is 0, then the next instruc-

tion, which is already fetched, is dis-

carded and an NOP is executed

instead making it a two cycle instruc-

tion.

Words: 1 Cycles: 1(2) Example:

HERE INCFSZ CNT, 1

GOTO LOOP

CONTINUE •

•

Before Instruction

PC = address (HERE)

After Instruction

CNT = CNT + 1; if CNT = 0, PC = address (CONTINUE); if CNT ≠ 0, PC = address (HERE +1)

IORLW Inclusive OR literal with W

Syntax: [

label

] IORLW k Operands: 0 ≤ k ≤ 255 Operation: (W) .OR. (k) → (W) Status Affected: Z Encoding:

1101 kkkk kkkk

Description:

The contents of the W register are OR’ed with the eight bit literal 'k'. The result is placed in the W register.

Words: 1 Cycles: 1 Example:

IORLW 0x35

Before Instruction

W = 0x9A

After Instruction

W = 0xBF Z = 0

IORWF Inclusive OR W with f

Syntax: [

label

] IORWF f,d Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (W).OR. (f) → (dest) Status Affected: Z Encoding:

0001 00df ffff

Description:

Inclusive OR the W register with regis-

ter 'f'. If 'd' is 0 the result is placed in

the W register. If 'd' is 1 the result is

placed back in register 'f'.

Words: 1 Cycles: 1 Example:

IORWF RESULT, 0

Before Instruction

RESULT = 0x13 W = 0x91

After Instruction

RESULT = 0x13 W = 0x93 Z = 0

PIC12C5XX

DS40139B-page 44  1997 Microchip Technology Inc.

MOVF Move f

Syntax: [

label

] MOVF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (f) → (dest) Status Affected: Z Encoding:

0010 00df ffff

Description:

The contents of register 'f' is moved to

destination 'd'. If 'd' is 0, destination is

the W register. If 'd' is 1, the destination

is ﬁle register 'f'. 'd' is 1 is useful to test

a ﬁle register since status ﬂag Z is

affected.

Words: 1 Cycles: 1 Example:

MOVF FSR, 0

After Instruction

W = value in FSR register

MOVLW Move Literal to W

Syntax: [

label

] MOVLW k Operands: 0 ≤ k ≤ 255 Operation: k → (W) Status Affected: None Encoding:

1100 kkkk kkkk

Description:

The eight bit literal 'k' is loaded into the W register. The don’t cares will assemble as 0s.

Words: 1 Cycles: 1 Example:

MOVLW 0x5A

After Instruction

W = 0x5A

MOVWF Move W to f

Syntax: [

label

] MOVWF f Operands: 0 ≤ f ≤ 31 Operation: (W) → (f) Status Affected: None Encoding:

0000 001f ffff

Description:

Move data from the W register to register 'f'

. Words: 1 Cycles: 1 Example:

MOVWF TEMP_REG

Before Instruction

TEMP_REG = 0xFF W = 0x4F

After Instruction

TEMP_REG = 0x4F W = 0x4F

NOP No Operation

Syntax: [

label

] NOP Operands: None Operation: No operation Status Affected: None Encoding:

0000 0000 0000

Description: No operation. Words: 1 Cycles: 1 Example:

NOP

 1997 Microchip Technology Inc. DS40139B-page 45

PIC12C5XX

OPTION Load OPTION Register

Syntax: [

label

] OPTION Operands: None Operation: (W) → OPTION Status Affected: None Encoding:

0000 0000 0010

Description:

The content of the W register is loaded into the OPTION register.

Words: 1 Cycles: 1 Example

OPTION

Before Instruction

W = 0x07

After Instruction

OPTION = 0x07

RETLW Return with Literal in W

Syntax: [

label

] RETLW k Operands: 0 ≤ k ≤ 255 Operation: k → (W);

TOS → PC Status Affected: None Encoding:

1000 kkkk kkkk

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: 1 Cycles: 2 Example:

TABLE

CALL TABLE ;W contains

;table offset

;value.

• ;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

RLF Rotate Left f through Carry

Syntax: [

label

] RLF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: See description below Status Affected: C Encoding:

0011 01df ffff

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 register 'f'.

Words: 1 Cycles: 1 Example:

RLF REG1,0

Before Instruction

REG1 = 1110 0110 C = 0

After Instruction

REG1 = 1110 0110 W = 1100 1100 C = 1

RRF Rotate Right f through Carry

Syntax: [

label

] RRF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: See description below Status Affected: C Encoding:

0011 00df ffff

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 register 'f'.

Words: 1 Cycles: 1 Example:

RRF REG1,0

Before Instruction

REG1 = 1110 0110 C = 0

After Instruction

REG1 = 1110 0110 W = 0111 0011 C = 0

PIC12C5XX

DS40139B-page 46  1997 Microchip Technology Inc.

SLEEP Enter SLEEP Mode

Syntax:

[

label

]

SLEEP Operands: None Operation: 00h → WDT;

0 → WDT prescaler; 1 → T

0 → PD Status Affected: TO, PD, GPWUF Encoding:

0000 0000 0011

Description:

Time-out status bit (TO) is set. The

power down status bit (PD) is cleared.

GPWUF is unaffected.

The WDT and its prescaler are

cleared.

The processor is put into SLEEP mode

with the oscillator stopped. See sec-

tion on SLEEP for more details.

Words: 1 Cycles: 1 Example: SLEEP

SUBWF Subtract W from f

Syntax:

[

label

] SUBWF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (f) – (W) → (dest) Status Affected: C, DC, Z Encoding:

0000 10df ffff

Description:

Subtract (2’s complement method) the

W register from register 'f'. If 'd' is 0 the

result is stored in the W register . If 'd' is

1 the result is stored back in register 'f'.

Words: 1 Cycles: 1 Example 1

SUBWF REG1, 1

Before Instruction

REG1 = 3 W = 2 C = ?

After Instruction

REG1 = 1 W = 2 C = 1 ; result is positive

Example 2:

Before Instruction

REG1 = 2 W = 2 C = ?

After Instruction

REG1 = 0 W = 2 C = 1 ; result is zero

Example 3:

Before Instruction

REG1 = 1 W = 2 C = ?

After Instruction

REG1 = FF W = 2 C = 0 ; result is negative

 1997 Microchip Technology Inc. DS40139B-page 47

PIC12C5XX

SWAPF Swap Nibbles in f

Syntax: [

label

] SWAPF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1]

Operation: (f<3:0>) → (dest<7:4>);

(f<7:4>) → (dest<3:0>) Status Affected: None Encoding:

0011 10df ffff

Description:

The upper and lower nibbles of register

'f' are exchanged. If 'd' is 0 the result is

placed in W register . If 'd' is 1 the result

is placed in register 'f'.

Words: 1 Cycles: 1 Example

SWAPF

REG1, 0

Before Instruction

REG1 = 0xA5

After Instruction

REG1 = 0xA5 W = 0X5A

TRIS Load TRIS Register

Syntax: [

label

] TRIS f

Operands: f =

Operation: (W) → TRIS register f Status Affected: None Encoding:

0000 0000 0fff

Description:

TRIS register 'f' (f = 6) is loaded with the

contents of the W register

Words: 1 Cycles: 1 Example

TRIS GPIO

Before Instruction

W = 0XA5

After Instruction

TRIS = 0XA5

Note: f = 6 for PIC12C5XX only.

XORLW Exclusive OR literal with W

Syntax:

[

label

] XORLW k Operands: 0 ≤ k ≤ 255 Operation: (W) .XOR. k → (W) Status Affected: Z Encoding:

1111 kkkk kkkk

Description:

The contents of the W register are XOR’ed with the eight bit literal 'k'. The result is placed in the W register.

Words: 1 Cycles: 1 Example: XORLW 0xAF

Before Instruction

W = 0xB5

After Instruction

W = 0x1A

XORWF Exclusive OR W with f

Syntax: [

label

] XORWF f,d

Operands: 0 ≤ f ≤ 31

d ∈ [0,1] Operation: (W) .XOR. (f) → (dest) Status Affected: Z Encoding:

0001 10df ffff

Description:

Exclusive OR the contents of the W

result is stored in the W register . If 'd' is

1 the result is stored back in register 'f'.

Words: 1 Cycles: 1 Example XORWF

REG,1

Before Instruction

REG = 0xAF W = 0xB5

After Instruction

REG = 0x1A W = 0xB5

PIC12C5XX

DS40139B-page 48  1997 Microchip Technology Inc.

NOTES:

 1997 Microchip Technology Inc. DS40139B-page 49

PIC12C5XX

9.0 DEVELOPMENT SUPPORT

9.1 Development Tools

The PIC16/17 microcontrollers are supported with a full range of hardware and software development tools:

• PICMASTER/PICMASTER CE Real-Time In-Circuit Emulator

• ICEPIC Low-Cost PIC16C5X and PIC16CXXX In-Circuit Emulator

• PRO MATE



II Universal Programmer

• PICSTART



Plus Entry-Level Prototype

Programmer

• PICDEM-1 Low-Cost Demonstration Board

• PICDEM-2 Low-Cost Demonstration Board

• PICDEM-3 Low-Cost Demonstration Board

• MPASM Assembler

• MPLAB-SIM Software Simulator

• MPLAB-C (C Compiler)

• Fuzzy logic development system (

fuzzy

TECH−MP)

9.2 PICMASTER: High Performance

Universal In-Circuit Emulator with MPLAB IDE

The PICMASTER Universal In-Circuit Emulator is intended to provide the product development engineer with a complete microcontroller design tool set for all microcontrollers in the PIC12C5XX, PIC14C000, PIC16C5X, PIC16CXXX and PIC17CXX families. PICMASTER is supplied with the MPLAB Integrated Development Environment (IDE), which allows editing, “make” and download, and source debugging from a single environment.

Interchangeable target probes allow the system to be easily reconﬁgured for emulation of different processors. The universal architecture of the PICMASTER allows expansion to support all new Microchip microcontrollers.

The PICMASTER Emulator System has been designed as a real-time emulation system with advanced features that are generally found on more expensive development tools. The PC compatible 386 (and higher) machine platform and Microsoft Windows



3.x environment were chosen to best make these fea-

tures available to you, the end user. A CE compliant version of PICMASTER is available for

European Union (EU) countries.

9.3 ICEPIC: Low-cost PIC16CXXX In-Circuit Emulator

ICEPIC is a low-cost in-circuit emulator solution for the Microchip PIC16C5X and PIC16CXXX families of 8-bit OTP microcontrollers.

ICEPIC is designed to operate on PC-compatible machines ranging from 286-AT



through Pentium based machines under Windows 3.x environment. ICEPIC features real time, non-intrusive emulation.

9.4 PRO MATE II: Universal Programmer

The PRO MATE II Universal Programmer is a full-featured programmer capable of operating in stand-alone mode as well as PC-hosted mode.

The PRO MATE II has programmable V

DD and VPP

supplies which allows it to verify programmed memory at V

DD min and VDD max for maximum reliability. It has

an LCD display for displaying error messages, keys to enter commands and a modular detachable socket assembly to support various package types. In standalone mode the PRO MATE II can read, verify or program PIC16C5X, PIC16CXXX, PIC17CXX, PIC14000 and PIC12C5XX devices. It can also set conﬁguration and code-protect bits in this mode.

9.5 PICSTART Plus Entry Level

Development System

The PICSTART programmer is an easy-to-use, lowcost 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 is not recommended for production programming.

PICSTART Plus supports all PIC12C5XX, PIC14000, PIC16C5X, PIC16CXXX and PIC17CXX devices with up to 40 pins. Larger pin count devices such as the PIC16C923 and PIC16C924 may be supported with an adapter socket.

PIC12C5XX

DS40139B-page 50  1997 Microchip Technology Inc.

9.6 PICDEM-1 Low-Cost PIC16/17 Demonstration Board

The PICDEM-1 is a simple board which demonstrates the capabilities of several of Microchip’s microcontrollers. 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 the PICDEM-1 board, on a PRO MATE II or PICSTART-16B programmer, and easily test ﬁrmware. The user can also connect the PICDEM-1 board to the PICMASTER emulator and download the ﬁrmware to the emulator for testing. Additional prototype area is available for the user to build some additional 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.

9.7 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 programmer or PICSTART-16C, and easily test ﬁrmware. The PICMASTER emulator may also be used with the PICDEM-2 board to test ﬁrmware. Additional prototype area has been provided to the user for adding additional hardware and connecting it to the microcontroller socket(s). Some of the features include a RS-232 interface, push-button switches, a potentiometer for simulated analog input, a Serial EEPROM to demonstrate usage of the I

C bus and separate headers for connec-

tion to an LCD module and a keypad.

9.8 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 necessary hardware and software is included to run the basic demonstration programs. The user can program the sample microcontrollers provided with the PICDEM-3 board, on a PRO MATE II programmer or PICSTART Plus with an adapter socket, and easily test ﬁrmware. The PICMASTER emulator may also be used with the PICDEM-3 board to test ﬁrmware. Additional prototype area has been provided to the user for adding hardware and connecting it to the microcontroller socket(s). Some of the f eatures include

an RS-232 interface, push-button switches, a potentiometer 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 segments, that is capable of displaying time, temperature and day of the week. The PICDEM-3 provides an additional RS-232 interface and Windows 3.1 software for showing the demultiplex ed LCD signals on a PC. A simple serial interface allows the user to construct a hardware demultiplexer for the LCD signals.

9.9 MPLAB Integrated Development Environment Software

The MPLAB IDE Software brings an ease of software development previously unseen in the 8-bit microcontroller market. MPLAB is a windows based application which contains:

• A full featured editor

• Three operating modes

- editor

- emulator

- simulator

• A project manager

• Customizable tool bar and key mapping

• A status bar with project information

• Extensive on-line help

MPLAB allows you to:

• Edit your source ﬁles (either assembly or ‘C’)

• One touch assemble (or compile) and download

to PIC16/17 tools (automatically updates all project information)

• Debug using:

- source ﬁles

- absolute listing ﬁle

• Transfer data dynamically via DDE (soon to be

replaced by OLE)

• Run up to four emulators on the same PC

The ability to use MPLAB with Microchip’s simulator allows a consistent platform and the ability to easily switch from the low cost simulator to the full featured emulator with minimal retraining due to development tools.

9.10 Assembler (MPASM)

The MPASM Universal Macro Assembler is a PChosted symbolic assembler. It suppor ts all microcontroller series including the PIC12C5XX, PIC14000, PIC16C5X, PIC16CXXX, and PIC17CXX families.

MPASM offers full featured Macro capabilities, conditional assembly, and several source and listing f ormats. It generates various object code formats to support Microchip's development tools as well as third party programmers.

MPASM allows full symbolic debugging from PICMASTER, Microchip’s Universal Emulator System.

 1997 Microchip Technology Inc. DS40139B-page 51

PIC12C5XX

MPASM has the following f eatures to assist in developing software for speciﬁc use applications.

• Provides translation of Assembler source code to object code for all Microchip microcontrollers.

• Macro assembly capability.

• Produces all the ﬁles (Object, Listing, Symbol, and special) required for symbolic debug with Microchip’s emulator systems.

• Supports Hex (default), Decimal and Octal source and listing formats.

MPASM provides a rich directive language to support programming of the PIC16/17. Directives are helpful in making the development of your assemb le source code shorter and more maintainable.

9.11 Software Simulator (MPLAB-SIM)

The MPLAB-SIM Software Simulator allows code development in a PC host environment. It allows the user to simulate the PIC16/17 series microcontrollers on an instruction level. On any given instruction, the user may examine or modify any of the data areas or provide external stimulus to any of the pins. The input/ output radix can be set by the user and the execution can be performed in; single step , e xecute until break, or in a trace mode.

MPLAB-SIM fully supports symbolic debugging using MPLAB-C and MPASM. The Software Simulator offers the low cost ﬂexibility to develop and debug code outside of the laboratory environment making it an excellent multi-project software development tool.

9.12 C Compiler (MPLAB-C)

The MPLAB-C Code Development System is a complete ‘C’ compiler and integrated development environment for Microchip’s PIC16/17 family of microcontrollers. The compiler provides powerful integration capabilities and ease of use not found with other compilers.

For easier source level debugging, the compiler provides symbol information that is compatible with the MPLAB IDE memory display (PICMASTER emulator software versions 1.13 and later).

9.13 Fuzzy Logic Development System

(

fuzzy

TECH-MP)

fuzzy

TECH-MP fuzzy logic development tool is available in two versions - a low cost introductory version, MP Explorer, for designers to gain a comprehensive working knowledge of fuzzy logic system design; and a full-featured version,

fuzzy

TECH-MP, edition for imple-

menting more complex systems. Both versions include Microchip’s

fuzzy

LAB demonstration board for hands-on experience with fuzzy logic systems implementation.

9.14 MP-DriveWay – Application Code

Generator

MP-DriveWay is an easy-to-use Windows-based Application Code Generator. With MP-DriveWay you can visually conﬁgure all the peripherals in a PIC16/17 device and, with a click of the mouse, generate all the initialization and many functional code modules in C language. The output is fully compatible with Microchip’s MPLAB-C C compiler. The code produced is highly modular and allows easy integration of your own code. MP-DriveWay is intelligent enough to maintain your code through subsequent code generation.

9.15 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.

9.16 KEELOQ Evaluation and Programming Tools

KEELOQ evaluation and programming tools support Microchips HCS Secure Data Products. The HCS evaluation kit includes an LCD display to show changing codes, a decoder to decode transmissions, and a programming interface to program test transmitters.

PIC12C5XX

DS40139B-page 52  1997 Microchip Technology Inc.

TABLE 9-1: DEVELOPMENT TOOLS FROM MICROCHIP

PIC12C5XX PIC14000 PIC16C5X PIC16CXXX PIC16C6X PIC16C7XX PIC16C8X PIC16C9XX PIC17C4X PIC17C75X

24CXX

25CXX

93CXX

HCS200

HCS300

HCS301

Emulator Products

PICMASTER



PICMASTER-CE

In-Circuit Emulator

✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

Available

3Q97

ICEPIC Low-Cost

In-Circuit Emulator

✔ ✔ ✔ ✔ ✔ ✔

Software Tools

MPLAB

Integrated

Development

Environment

✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

MPLAB C

Compiler

✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

fuzzy

TECH



-MP

Explorer/Edition

Fuzzy Logic

Dev. Tool

✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

MP-DriveWay

Applications

Code Generator

✔ ✔ ✔ ✔ ✔ ✔

Total Endurance

Software Model

✔

Programmers

PICSTART



Lite Ultra Low-Cost

Dev. Kit

✔ ✔ ✔ ✔

PICSTART



Plus Low-Cost

Universal Dev. Kit

✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

PRO MATE



Universal

Programmer

✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

KEELOQ



Programmer

✔

Demo Boards

SEEVALDesigners Kit

✔

PICDEM-1

✔ ✔ ✔ ✔

PICDEM-2

✔ ✔

PICDEM-3

✔

KEELOQ



Evaluation Kit

✔

 1997 Microchip Technology Inc. DS40139B-page 53

PIC12C5XX

10.0 ELECTRICAL CHARACTERISTICS - PIC12C5XX

Absolute Maximum Ratings†

Ambient Temperature under bias............................................................................................................ –40˚C to +125˚C

Storage Temperature .............................................................................................................................. –65˚C to +150˚C

Voltage on V

DD with respect to VSS ..................................................................................................................0 to +7.5 V

Voltage on MCLR

with respect to VSS ...............................................................................................................0 to +14 V

Voltage on all other pins with respect to V

SS .................................................................................–0.6 V to (VDD + 0.6 V)

Total Power Dissipation

(1)

.....................................................................................................................................700 mW

Max. Current out of V

SS pin....................................................................................................................................200 mA

Max. Current into V

DD pin.......................................................................................................................................150 mA

Input Clamp Current, I

IK (VI < 0 or VI > VDD).....................................................................................................................±20 mA

Output Clamp Current, I

OK (VO < 0 or VO > VDD).............................................................................................................±20 mA

Max. Output Current sunk by any I/O pin.................................................................................................................25 mA

Max. Output Current sourced by any I/O pin............................................................................................................25 mA

Max. Output Current sourced by I/O port (GPIO)...................................................................................................100 mA

Max. Output Current sunk by I/O port (GPIO ).......................................................................................................100 mA

Note 1: Power Dissipation is calculated as follows: P

DIS = VDD x {IDD - ∑ IOH} + ∑ {(VDD-VOH) x IOH} + ∑(VOL x IOL)

†

NOTICE: Stresses above those listed under "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.

PIC12C5XX

DS40139B-page 54  1997 Microchip Technology Inc.

10.1 DC CHARACTERISTICS: PIC12508/509 (Commercial) PIC12508/509 (Industrial) PIC12508/509 (Extended)

DC Characteristics Power Supply Pins

Standard Operating Conditions (unless otherwise speciﬁed)

Operating Temperature 0°C ≤ TA ≤ +70°C (commercial)

–40°C ≤ T

A ≤ +85°C (industrial)

–40°C ≤ T

A ≤ +125°C (extended)

Characteristic Sym Min

Typ

(1)

Max Units Conditions

Supply Voltage V

DD 2.5

3.0

5.5

VVFOSC = DC to 4 MHz (Commercial/

Industrial) F

OSC = DC to 4 MHz (Extended)

RAM Data Retention Voltage

(2)

VDR 1.5* V Device in SLEEP mode

DD Start Voltage to ensure

Power-on Reset

VPOR VSS V See section on Power-on Reset for details

DD Rise Rate to ensure

Power-on Reset

SVDD 0.05* V/ms See section on Power-on Reset for details

Supply Current

(3)

IDD —

— — — —

1.8

1.8 15 19 19

2.4

2.4 27 35 35

mA mA

µA µA µA

XT and EXTRC options (Note 4) F

OSC = 4 MHz, VDD = 5.5V

INTRC Option F

OSC = 4 MHz, VDD = 5.5V

LP O

PTION, Commercial Temperature

OSC = 32 kHz, VDD = 3.0V, WDT disabled

LP O

PTION, Industrial Temperature

OSC = 32 kHz, VDD = 3.0V, WDT disabled

LP O

PTION, Extended Temperature

OSC = 32 kHz, VDD = 3.0V, WDT disabled

Power-Down Current

(5)

WDT Enabled

WDT Disabled

— — — — — —

4 4 5

0.25

0.25 2

12 14 22

4 5

µA µA µA µA µA µA

DD = 3.0V, Commercial

DD = 3.0V, Industrial

DD = 3.0V, Extended

DD = 3.0V, Commercial

DD = 3.0V, Industrial

DD = 3.0V, Extended

* These parameters are characterized but not tested. Note 1: Data in the Typical (“Typ”) column is based on characterization results at 25°C. This data is for design guid-

ance only and is not tested.

2: This is the limit to which V

DD 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 I

DD measurements in active operation mode are:

OSC1 = external square wave, from rail-to-rail; all I/O pins tristated, pulled to V

ss, T0CKI = VDD, MCLR = VDD; WDT enabled/disabled as speciﬁed.

b) For standby current measurements, the conditions are the same, except that

the device is in SLEEP mode.

4: Does not include current through Rext. The current through the resistor can be estimated by the

formula: I

R = 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 mea-

sured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to V

DD or VSS.

 1997 Microchip Technology Inc. DS40139B-page 55

PIC12C5XX

10.2 DC CHARACTERISTICS: PIC12508/509 (Commercial) PIC12508/509 (Industrial) PIC12508/509 (Extended)

DC Characteristics

All Pins Except

Power Supply Pins

Standard Operating Conditions (unless otherwise speciﬁed)

Operating Temperature 0°C ≤ T

A ≤ +70°C (commercial)

–40°C ≤ T

A ≤ +85°C (industrial)

–40°C ≤ T

A ≤ +125°C (extended)

Operating Voltage V

DD range is described in Section 10.1.

Characteristic Sym Min Typ

(1)

Max Units Conditions

Input Low Voltage

I/O ports

MCLR and GP2 (Schmitt Trigger) OSC1 OSC1

VSS VSS VSS

VSS VSS

0.8

0.15 V

0.15 VDD

0.3 VDD

V V V

V V

Pin at hi-impedance

4.5V < V

DD ≤ 5.5V

Pin at hi-impedance

3.0V < V

DD ≤ 4.5V

EXTRC option only

(4)

XT and LP options

Input High Voltage

I/O ports

MCLR

and GP2 (Schmitt Trigger)

OSC1 (Schmitt Trigger) IPUR

0.25VDD+0.8V

2.0

0.2V

DD+1V

0.85 V

0.85 VDD

0.7 VDD

VDD VDD VDD VDD VDD VDD

V V V V V V

2.5V < V

DD ≤ 4.5V

4.5V < V

DD ≤ 5.5V

(5)

Full VDD range

(5)

EXTRC option only

(4)

XT and LP options

Input Leakage Current

(2,3)

I/O ports MCLR OSC1

–1 20 –3

0.5

130

0.5

250

+5 +3

µA µA

For V

DD ≤ 5.5V

SS ≤ VPIN ≤ VDD,

Pin at hi-impedance V

PIN = VSS + 0.25V

(2)

VPIN = VDD VSS ≤ VPIN ≤ VDD, XT and LP options

Output Low Voltage

I/O ports

Vol

0.6 V I

OL = 8.7 mA, VDD = 4.5V

Output High Voltage

(3,4)

I/O ports

VoH

DD –0.7 V IOH = –5.4 mA, VDD = 4.5V

* These parameters are characterized but not tested. Note 1: Data in the Typical (“Typ”) column is based on characterization results at 25°C. This data is for design guid-

ance only and is not tested.

2: The leakage current on the MCLR

/VPP 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 voltage.

3: Negative current is deﬁned as coming out of the pin. 4: For PIC12C5XX devices, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended that the

PIC12C5XX be driven with external clock in RC mode.

5: The user may use the better of the two speciﬁcations.

PIC12C5XX

DS40139B-page 56  1997 Microchip Technology Inc.

10.3 Timing Parameter Symbology and Load Conditions

The timing parameter symbols have been created following one of the following formats:

1. TppS2ppS

2. TppS

F Frequency T Time Lowercase subscripts (pp) and their meanings:

2 to mc MCLR ck CLKOUT osc oscillator cy cycle time os OSC1 drt device reset timer t0 T0CKI io I/O port wdt watchdog timer Uppercase letters and their meanings:

F Fall P Period H High R Rise I Invalid (Hi-impedance) V Valid L Low Z Hi-impedance

FIGURE 10-1: LOAD CONDITIONS - PIC12C5XX

VSS

L = 50 pF for all pins except OSC2

15 pF for OSC2 in XT, HS or LP

modes when external clock is used to drive OSC1

 1997 Microchip Technology Inc. DS40139B-page 57

PIC12C5XX

10.4 Timing Diagrams and Speciﬁcations FIGURE 10-2: EXTERNAL CLOCK TIMING - PIC12C5XX

TABLE 10-1: EXTERNAL CLOCK TIMING REQUIREMENTS - PIC12C5XX

AC Characteristics Standard Operating Conditions (unless otherwise speciﬁed)

Operating Temperature 0°C ≤ T

A ≤ +70°C (commercial),

–40°C ≤ T

A ≤ +85°C (industrial),

–40°C ≤ T

A ≤ +125°C (extended)

Operating Voltage V

DD range is described in Section 10.1

Parameter

No.

Sym Characteristic Min

Typ

(1)

Max Units Conditions

FOSC

External CLKIN Frequency

(2)

DC — 4 MHz EXTRC osc mode DC — 4 MHz XT osc mode DC — 200 kHz LP osc mode

Oscillator Frequency

(2)

DC — 4 MHz EXTRC osc mode

0.1 — 4 MHz XT osc mode

DC — 200 kHz LP osc mode

1 T

OSC

External CLKIN Period

(2)

250 — — ns EXTRC osc mode 250 — — ns XT osc mode

5 — — ms LP osc mode

Oscillator Period

(2)

250 — — ns EXTRC osc mode 250 — 10,000 ns XT osc mode

5 — — ms LP osc mode

2 Tcy

Instruction Cycle Time

(3)

— 4/FOSC — —

3 TosL, TosH Clock in (OSC1) Low or High Time 50* — — ns XT oscillator

2* — — ms LP oscillator

4 TosR, TosF Clock in (OSC1) Rise or Fall Time — — 25* ns XT oscillator

— — 50* ns LP oscillator

* 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.

2: All speciﬁed values are based on characterization data for that particular oscillator type under standard oper-

ating conditions with the device executing code. Exceeding these speciﬁed limits may result in an unstable oscillator operation and/or higher than expected current consumption. When an external clock input is used, the “max” cycle time limit is “DC” (no clock) for all devices.

3: Instruction cycle period (T

CY) equals four times the input oscillator time base period.

OSC1

Q1 Q2

Q3 Q4 Q1

1 3 3

4 4

PIC12C5XX

DS40139B-page 58  1997 Microchip Technology Inc.

FIGURE 10-3: I/O TIMING - PIC12C5XX

TABLE 10-2: TIMING REQUIREMENTS - PIC12C5XX

AC Characteristics Standard Operating Conditions (unless otherwise speciﬁed)

Operating Temperature 0°C ≤ T

A ≤ +70°C (commercial)

–40°C ≤ T

A ≤ +85°C (industrial)

–40°C ≤ T

A ≤ +125°C (extended)

Operating Voltage V

DD range is described in Section 10.1

Parameter

No. Sym Characteristic Min Typ

(1)

Max Units

TosH2ioV

OSC1↑ (Q1 cycle) to Port out valid

(3)

— — 100* ns

TosH2ioI OSC1↑ (Q2 cycle) to Port input invalid

(I/O in hold time)

TBD — — ns

TioV2osH Port input valid to OSC1↑

(I/O in setup time)

TBD — — ns

TioR

Port output rise time

(3)

— 10 25** ns

TioF

Port output fall time

(3)

— 10 25** ns

* These parameters are characterized but not tested. ** These parameters are design targets and are not tested. No characterization data available at this time.

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. 2: Measurements are taken in EXTRC mode. 3: See Figure 10-1 for loading conditions.

OSC1

I/O Pin

(input)

I/O Pin

(output)

Q2 Q3

20, 21

Old Value

New Value

Note: All tests must be done with speciﬁed capacitive loads (see data sheet) 50 pF on I/O pins and CLKOUT.

 1997 Microchip Technology Inc. DS40139B-page 59

PIC12C5XX

FIGURE 10-4: RESET, WATCHDOG TIMER, AND DEVICE RESET TIMER TIMING - PIC12C5XX

TABLE 10-3: RESET, WATCHDOG TIMER, AND DEVICE RESET TIMER - PIC12C5XX

TABLE 10-4: DRT (DEVICE RESET TIMER PERIOD)

AC Characteristics Standard Operating Conditions (unless otherwise speciﬁed)

Operating Temperature 0°C ≤ T

A ≤ +70°C (commercial)

–40°C ≤ T

A ≤ +85°C (industrial)

–40°C ≤ T

A ≤ +125°C (extended)

Operating Voltage V

DD range is described in Section 10.1

Parameter

No. Sym Characteristic Min Typ

(1)

Max Units Conditions

TmcL MCLR Pulse Width (low) 2000* — — ns VDD = 5 V

Twdt Watchdog Timer Time-out Period

(No Prescaler)

9* 18* 30* ms VDD = 5 V (Commercial)

TDRT Device Reset Timer Period

(2)

9* 18* 30* ms VDD = 5 V (Commercial)

TioZ I/O Hi-impedance from MCLR Low — — 2000* ns

* 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.

Oscillator Conﬁguration POR Reset Subsequent Resets

IntRC & ExtRC 18 ms (typical) 300 µs (typical) XT & LP 18 ms (typical) 18 ms (typical)

VDD

MCLR

Internal

POR

DRT

Timeout

Internal

RESET

Watchdog

Timer

RESET

I/O pin

(Note 1)

Note 1: I/O pins must be taken out of hi-impedance mode by enabling the output drivers in software.

(Note 2)

2: Runs in MCLR or WDT reset only in XT and LP modes.

PIC12C5XX

DS40139B-page 60  1997 Microchip Technology Inc.

FIGURE 10-5: TIMER0 CLOCK TIMINGS - PIC12C5XX

TABLE 10-5: TIMER0 CLOCK REQUIREMENTS - PIC12C5XX

TABLE 10-6: PULL-UP RESISTOR RANGES

AC Characteristics Standard Operating Conditions (unless otherwise speciﬁed)

Operating Temperature 0°C ≤ T

A ≤ +70°C (commercial)

–40°C ≤ T

A ≤ +85°C (industrial)

–40°C ≤ T

A ≤ +125°C (extended)

Operating Voltage V

DD range is described in Section 10.1.

Parameter

No.

Sym Characteristic Min Typ

(1)

Max Units Conditions

40 Tt0H T0CKI High Pulse Width - No Prescaler 0.5 TCY + 20* — — ns

- With Prescaler 10* — — ns

41 Tt0L T0CKI Low Pulse Width - No Prescaler 0.5 TCY + 20* — — ns

- With Prescaler 10* — — ns

42 Tt0P T0CKI Period 20 or TCY + 40*

— — ns Whichever is greater.

N = Prescale Value

(1, 2, 4,..., 256)

* 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.

VDD (Volts) Temperature (°C) Min Typ Max Units

GP0/GP1

2.5 -40 50K 62K 84K Ω 25 63K 73K 84K Ω 85 63K 80K 84K Ω

125 63K 81K 84K Ω

5.5 -40 19K 22K 27K Ω 25 25K 27K 31K Ω 85 28K 33K 40K Ω

125 31K 36K 43K Ω

GP3

2.5 -40 490K 710K 965K Ω 25 610K 890K 1.2M Ω 85 769K 1.1M 1.5M Ω

125 810K 1.2M 1.6M Ω

5.5 -40 310K 410K 510K Ω 25 360K 470K 580K Ω 85 430K 550K 670K Ω

125 465K 585K 715K Ω

* These parameters are characterized but not tested.

T0CKI

40 41

 1997 Microchip Technology Inc. DS40139B-page 61

PIC12C5XX

11.0 DC AND AC CHARACTERISTICS - PIC12C5XX

The graphs and tables provided in this section are for design guidance and are not tested or guaranteed. In some graphs or tables the data presented are outside speciﬁed operating range (e.g., outside speciﬁed V

DD 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 11-1: CALIBRATED INTERNAL RC FREQUENCY RANGE VS. TEMPERATURE (VDD = 5.0V)

(INTERNAL RC IS CALIBRATED TO 25°C, 5.0V)

FIGURE 11-2: CALIBRATED INTERNAL RC FREQUENCY RANGE VS. TEMPERATURE (V

DD = 3.0V)

(INTERNAL RC IS CALIBRATED TO 25°C, 5.0V)

Temperature (°C)

Frequency (MHz)

-40 25 85

3.7

3.95

4.2

125

3.75

3.8

3.85

3.9

4.0

4.05

4.1

4.15

Frequency (MHz)

3.6

4.1

3.7

3.8

3.9

4.0

3.5

Temperature (°C)

-40 25 85

125

PIC12C5XX

DS40139B-page 62  1997 Microchip Technology Inc.

FIGURE 11-3: INTERNAL RC FREQUENCY VS. CALIBRATION VALUE (VDD = 5.5V)

FIGURE 11-4: INTERNAL RC FREQUENCY VS. CALIBRATION VALUE (V

DD = 3.5V)

TABLE 11-1: DYNAMIC I

DD (TYPICAL) - WDT ENABLED, 25°C

Oscillator Frequency VDD = 2.5V VDD = 5.5V

External RC 4 MHz 250 µA* 620 µA* Internal RC 4 MHz 420 µA 1.1 mA XT 4 MHz 251 µA 775 µA LP 32 KHz 7 µA 37 µA *Does not include current through external R&C.

OSCCAL Value (Hex)

Frequency (MHz)

00 10 20 30 40 50 60 70 80 90 A0 B0 C0 D0 E0 F0

3.30

4.05

4.80

3.45

3.60

3.75

3.90

4.20

4.35

4.50

4.65

+125°C

+85°C

+25°C

-40°C

00 10 20 30 40 50 60 70 80 90 A0 B0 C0 D0 E0 F0

OSCCAL Value (Hex)

Frequency (MHz)

3.30

4.05

4.80

3.45

3.60

3.75

3.90

4.20

4.35

4.50

4.65

+125°C

+85°C

+25°C

-40°C

 1997 Microchip Technology Inc. DS40139B-page 63

PIC12C5XX

FIGURE 11-5: WDT TIMER TIME-OUT

PERIOD vs. VDD

2 3 4 5 6 7

DD (Volts)

WDT period (µs)

Max +125°C

Max +85°C

Typ +25°C

MIn –40°C

FIGURE 11-6: SHORT DRT PERIOD VS. VDD

1000

900

800

700

600

500

400

300

200

100

2 3 4 5 6 7

DD (Volts)

WDT period (µs)

Max +125°C

Max +85°C

Typ +25°C

MIn –40°C

PIC12C5XX

DS40139B-page 64  1997 Microchip Technology Inc.

FIGURE 11-7: IOH vs. VOH, VDD = 2.5 V

FIGURE 11-8: IOH vs. VOH, VDD = 5.5 V

500m 1.0 1.5

VOH (Volts)

IOH (mA)

2.0 2.5

-1

-2

-3

-4

-5

-6

-7

Min +125°C

Max –40°C

Typ +25°C

Min +85°C

3.5 4.0 4.5

VOH (Volts)

IOH (mA)

5.0 5.5

-5

-10

-15

-20

-25

-30

Min +125°C

Max –40°C

Typ +25°C

Min +85°C

FIGURE 11-9: IOL vs. VOL, VDD = 2.5 V

FIGURE 11-10: IOL vs. VOL, VDD = 5.5 V

250.0m 500.0m 1.0 V

OL (Volts)

IOL (mA)

Min +85°C

Max –40°C

Typ +25°C

Min +125°C

500.0m 750.0m 1.0 V

OL (Volts)

IOL (mA)

250.0m

Min +85°C

Max –40°C

Typ +25°C

Min +125°C

 1997 Microchip Technology Inc. DS40139B-page 65

PIC12C5XX

12.0 PACKAGING INFORMATION

12.1 Package Marking Information

Legend: MM...M Microchip part number information

XX...X Customer speciﬁc information* AA Year code (last 2 digits of calendar year) BB Week code (week of January 1 is week ‘01’) C Facility code of the plant at which wafer is manufactured

C = Chandler, Arizona, U.S.A.,

S = Tempe, Arizona, U.S.A. D Mask revision number E 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.

MMMMMMMM XXXXXCDE

AABB

8-Lead PDIP (300 mil)

Example

8-Lead SOIC (208 mil)

MMMMMMM AABBCDE

XXXXXXX

8-Lead Windowed Ceramic Side Brazed (300 mil)

MMMMMM

Example

12C508/P 04ISAZ

9625

12C508 9624SAZ

04I/SM

12C508

PIC12C5XX

DS40139B-page 66  1997 Microchip Technology Inc.

12.2 8-Lead Plastic Dual In-line (300 mil)

Package Group: Plastic Dual In-Line (PLA)

Symbol

Millimeters Inches

Min Max Notes Min Max Notes

α 0° 10° 0° 10°

A – 4.064 – 0.160 A1 0.381 – 0.015 – A2 3.048 3.810 0.120 0.150

B 0.355 0.559 0.014 0.022 B1 1.397 1.651 0.055 0.065

C 0.203 0.381 Typical 0.008 0.015 Typical

D 9.017 10.922 0.355 0.430 D1 7.620 7.620 Reference 0.300 0.300 Reference

E 7.620 8.255 0.300 0.325 E1 6.096 7.112 0.240 0.280 e1 2.489 2.591 Typical 0.098 0.102 Typical eA 7.620 7.620 Reference 0.300 0.300 Reference eB 7.874 9.906 0.310 0.390

L 3.048 3.556 0.120 0.140 N 8 8 8 8 S 0.889 – 0.035 –

S1 0.254 – 0.010 –

Pin No. 1 Indicator Area

Base Plane

Seating Plane

 1997 Microchip Technology Inc. DS40139B-page 67

PIC12C5XX

12.3 8-Lead Plastic Surface Mount (SOIC - Medium, 208 mil Body)

Package Group: Plastic SOIC (SM)

Symbol

Millimeters Inches

Min Max Notes Min Max Notes

α 0° 8° 0° 8° A 1.778 2.00 0.070 0.079

A1 0.101 0.249 0.004 0.010

B 0.355 0.483 0.014 0.019 C 0.190 0.249 0.007 0.010 D 5.080 5.334 0.200 0.210 E 5.156 5.411 0.203 0.213

e 1.270 1.270 Reference 0.050 0.050 Reference

H* 7.670 8.103 0.302 0.319

h 0.381 0.762 0.015 0.030 L 0.508 1.016 0.020 0.040

N 14 14 14 14

CP – 0.102 – 0.004

Index Area

Chamfer h x 45°

h x 45°

Seating Plane

Base Plane

PIC12C5XX

DS40139B-page 68  1997 Microchip Technology Inc.

12.4 8-Lead Ceramic Side Brazed Dual In-Line with Window (JW) (300 mil)

Package Group: Ceramic Side Brazed Dual In-Line (CER)

Symbol

Millimeters Inches

Min Max Notes Min Max Notes

α 0° 10° 0° 10° A 3.937 5.030 0.155 0.198

A1 0.635 1.143 0.025 0.045 A2 2.921 3.429 0.115 0.135 A3 1.778 2.413 0.070 0.095

B 0.406 0.508 0.016 0.020

B1 1.371 1.371 Typical 0.054 0.054 Typical

C 0.228 0.305 Typical 0.009 0.012 Typical D 13.004 13.412 0.512 0.528

D1 7.416 7.824 BSC 0.292 0.308 BSC

E 7.569 8.230 0.298 0.324

E1 7.112 7.620 0.280 0.300 e1 2.540 2.540 Typical 0.100 0.100 Typical eA 7.620 7.620 BSC 0.300 0.300 BSC eB 7.620 9.652 0.300 0.380

L 3.302 4.064 0.130 0.160 S 2.540 3.048 0.100 0.120

S1 0.127 — 0.005 —

Pin No. 1 Indicator Area

A3AA2

Base Plane

Seating Plane

 1997 Microchip Technology Inc. DS40139B-page 69

PIC12C5XX

INDEX A

ALU...................................................................................... 7

Applications.......................................................................... 3

Architectural Overview......................................................... 7

Assembler.......................................................................... 50

Block Diagram

On-Chip Reset Circuit................................................ 30

Timer0........................................................................ 21

TMR0/WDT Prescaler................................................ 24

Watchdog Timer......................................................... 33

Brown-Out Protection Circuit ............................................. 34

C Compiler (MP-C) ............................................................ 51

Carry.................................................................................... 7

Clocking Scheme............................................................... 10

Code Protection........................................................... 25, 35

Configuration Bits............................................................... 25

Configuration Word

PIC12C508/509 ......................................................... 25

Development Support........................................................ 49

Development Tools............................................................ 49

Device Varieties................................................................... 5

Digit Carry............................................................................ 7

Features............................................................................... 1

FSR.................................................................................... 17

Fuzzy Logic Dev. System (

fuzzy

TECH-MP).............. 49, 51

I/O Interfacing .................................................................... 19

I/O Ports............................................................................. 19

I/O Programming Considerations....................................... 20

ID Locations................................................................. 25, 35

INDF................................................................................... 17

Indirect Data Addressing.................................................... 17

Instruction Cycle ................................................................ 10

Instruction Flow/Pipelining................................................. 10

Instruction Set Summary.................................................... 38

Internal Weak Pull-ups..................................................15, 19

Loading of PC.................................................................... 16

Memory Organization......................................................... 11

Data Memory .............................................................12

Program Memory....................................................... 11

MPASM Assembler...................................................... 49, 50

MP-C C Compiler............................................................... 51

MPSIM Software Simulator.......................................... 49, 51

One-Time-Programmable (OTP) Devices............................ 5

OPTION Register............................................................... 15

OSC Selection ................................................................... 25

Oscillator Configurations.................................................... 26

Oscillator Types

INTRL..........................................................................26

LP............................................................................... 26

EXT RC...................................................................... 26

XT .............................................................................. 26

Package Marking Information ............................................ 65

Packaging Information....................................................... 65

PC...................................................................................... 16

PICDEM-1 Low-Cost PIC16/17 Demo Board............... 49, 50

PICDEM-2 Low-Cost PIC16CXX Demo Board............. 49, 50

PICDEM-3 Low-Cost PIC16C9XXX Demo Board.............. 50

PICMASTER



RT In-Circuit Emulator ................................... 49

PICSTART Low-Cost Development System....................... 49

Pin Compatible Devices............................................................ 76

POR

Device Reset Timer (DRT)................................... 25, 32

PD............................................................................... 34

Power-On Reset (POR) ..............................................25

TO............................................................................... 34

GPIO................................................................................... 19

Power-Down Mode............................................................. 35

Prescaler ............................................................................ 24

PRO MATE Universal Programmer.................................. 49

Program Counter................................................................ 16

Q cycles.............................................................................. 10

RC Oscillator ...................................................................... 27

Read Modify Write ..............................................................20

PIC12C508/509.......................................................... 12

Registers

Special Function......................................................... 13

Reset.................................................................................. 25

Reset on Brown-Out........................................................... 34

SLEEP.......................................................................... 25, 35

Software Simulator (MPSIM).............................................. 51

Special Features of the CPU.............................................. 25

Special Function Registers................................................. 13

Stack................................................................................... 16

STATUS ............................................................................... 7

STATUS Register............................................................... 14

Timer0

Switching Prescaler Assignment................................ 24

Timer0 ........................................................................ 21

Timer0 (TMR0) Module .............................................. 21

TMR0 with External Clock.......................................... 23

Timing Diagrams and Specifications.................................. 57

Timing Parameter Symbology and Load Conditions.......... 56

TRIS Registers................................................................... 19

Wake-up on Change............................................................19

Wake-up from SLEEP ........................................................ 35

Watchdog Timer (WDT)................................................ 25, 32

Period......................................................................... 33

Programming Considerations..................................... 33

Zero bit ................................................................................. 7

PIC12C5XX

DS40139B-page 70  1997 Microchip Technology Inc.

LIST OF EXAMPLES

Example 3-1: Instruction Pipeline Flow ............................10

Example 4-1: Indirect Addressing.................................... 17

Example 4-2: How To Clear RAM Using Indirect

Addressing................................................. 17

Example 5-1: Read-Modify-Write Instructions on an

I/O Port ...................................................... 20

Example 6-1: Changing Prescaler (Timer0→WDT)......... 24

Example 6-2: Changing Prescaler (WDT→Timer0)......... 24

LIST OF FIGURES

Figure 3-1: PIC12C5XX Block Diagram......................... 8

Figure 3-2: Clock/Instruction Cycle.............................. 10

Figure 4-1: Program Memory Map and Stack for the

PIC12C5XX ............................................... 11

Figure 4-2: PIC12C508 Register File Map................... 12

Figure 4-3: PIC12C509 Register File Map................... 12

Figure 4-4: STATUS Register (Address:03h)............... 14

Figure 4-5: OPTION Register....................................... 15

Figure 4-6: Loading of PC Branch Instructions -

PIC12C508/C509....................................... 16

Figure 4-7: Direct/Indirect Addressing.......................... 17

Figure 5-1: Equivalent Circuit for a Single I/O Pin........ 19

Figure 5-2: Successive I/O Operation.......................... 20

Figure 6-1: Timer0 Block Diagram............................... 21

Figure 6-2: Timer0 Timing: Internal Clock/

No Prescale............................................... 22

Figure 6-3: Timer0 Timing: Internal Clock/

Prescale 1:2............................................... 22

Figure 6-4: Timer0 Timing With External Clock ........... 23

Figure 6-5: Block Diagram of the Timer0/

WDT Prescaler .......................................... 24

Figure 7-1: Configuration Word for PIC12C508 or

PIC12C509................................................ 25

Figure 7-2: Crystal Operation (or Ceramic Resonator)

(XT or LP OSC Configuration)................... 26

Figure 7-3: External Clock Input Operation

(XT or LP OSC Configuration)................... 26

Figure 7-4: External Parallel Resonant Crystal

Oscillator Circuit......................................... 27

Figure 7-5: External Series Resonant Crystal

Oscillator Circuit .........................................27

Figure 7-6: External RC Oscillator Mode ..................... 27

Figure 7-7: MCLR

Select.............................................. 29

Figure 7-8: Simplified Block Diagram of

On-Chip Reset Circuit................................ 30

Figure 7-9: Time-Out Sequence on Power-Up

(MCLR Pulled Low).................................... 31

Figure 7-10: Time-Out Sequence on Power-Up

(MCLR Tied to Vdd): Fast VDD

Rise Time................................................... 31

Figure 7-11: Time-Out Sequence on Power-Up

(MCLR Tied to VDD): Slow VDD

Rise Time................................................... 31

Figure 7-12: Watchdog Timer Block Diagram................ 33

Figure 7-13: Brown-Out Protection Circuit 1.................. 34

Figure 7-14: Brown-Out Protection Circuit 2.................. 34

Figure 7-15: Typical In-Circuit Serial Programming

Connection................................................. 36

Figure 8-1: General Format for Instructions................. 37

Figure 10-1: Load Conditions - PIC12C5XX.................. 56

Figure 10-2: External Clock Timing - PIC12C5XX......... 57

Figure 10-3: I/O Timing - PIC12C5XX............................ 58

Figure 10-4: Reset, Watchdog Timer, and Device

Reset Timer Timing - PIC12C5XX............. 59

Figure 10-5: Timer0 Clock Timings - PIC12C5XX ......... 60

Figure 11-1: Calibrated Internal RC Frequency

Range vs. Temperature (V

DD = 5.0V)

(Internal RC is Calibrated to 25°C, 5.0V) .. 61

Figure 11-2: Calibrated Internal RC Frequency

Range vs. Temperature (VDD = 3.0V) (Internal RC is Calibrated to 25°C, 5.0V) .. 61

Figure 11-3: Internal RC Frequency vs.

Calibration Value (VDD = 5.5V)................... 62

Figure 11-4: Internal RC Frequency vs.

Calibration Value (VDD = 3.5V)................... 62

Figure 11-5: WDT Timer Time-out Period vs. VDD ........ 63

Figure 11-6: Short DRT Period vs. VDD......................... 63

Figure 11-7: IOH vs. VOH, VDD = 2.5 V........................... 64

Figure 11-8: IOH vs. VOH, VDD = 5.5 V........................... 64

Figure 11-9: IOL vs. VOL, VDD = 2.5 V............................ 64

Figure 11-10: IOL vs. VOL, VDD = 5.5 V............................ 64

LIST OF TABLES

Table 1-1: PIC12C5XX Family of Devices.................... 4

Table 3-1: PIC12C5XX Pinout Description................... 9

Table 4-1: Special Function Register Summary......... 13

Table 5-1: Summary of Port Registers ....................... 19

Table 6-1: Registers Associated With Timer0 ............ 22

Table 7-1: Capacitor Selection For Ceramic

Resonators - PIC12C5XX ......................... 26

Table 7-2: Capacitor Selection For Crystal

Oscillator - PIC12C5XX............................. 26

Table 7-3: Reset Conditions For Registers ................ 28

Table 7-4: Reset Condition For Special

Registers................................................... 29

Table 7-5: DRT (Device Reset Timer Period).............. 32

Table 7-6: Summary of Registers Associated

with the Watchdog Timer........................... 33

Table 7-7: TO

/PD/GPWUF Status After Reset........... 34

Table 7-8: Events Affecting TO/PD Status Bits .......... 34

Table 8-1: OPCODE Field Descriptions ..................... 37

Table 8-2: Instruction Set Summary........................... 38

Table 9-1: Development Tools From Microchip.......... 52

Table 10-1: External Clock Timing Requirements -

PIC12C5XX............................................... 57

Table 10-2: Timing Requirements - PIC12C5XX.......... 58

Table 10-3: Reset, Watchdog Timer, and Device

Reset Timer - PIC12C5XX........................ 59

Table 10-4: DRT (Device Reset Timer Period).............. 59

Table 10-5: Timer0 Clock Requirements -

PIC12C5XX............................................... 60

Table 10-6: Pull-up Resistor Ranges............................ 60

Table 11-1: Dynamic IDD (Typical) -

WDT Enabled, 25°C.................................. 62

 1997 Microchip Technology Inc. DS40139B-page 71

PIC12C5XX

ON-LINE SUPPORT

Microchip provides two methods of on-line support. These are the Microchip BBS and the Microchip World Wide Web (WWW) site.

Use Microchip's Bulletin Board Service (BBS) to get current information and help about Microchip products. Microchip provides the BBS communication channel for you to use in extending your technical staff with microcontroller and memory experts.

To provide you with the most responsive service possible, the Microchip systems team monitors the BBS, posts the latest component data and software tool updates, provides technical help and embedded systems insights, and discusses how Microchip products provide project solutions.

The web site, like the BBS, is used by Microchip as a means to make ﬁles and information easily available to customers. To view the site , the user m ust ha ve access to the Internet and a web browser, such as Netscape or Microsoft Explorer. Files are also available for FTP download from our FTP site.

Connecting to the Microchip Internet Web Site

The Microchip web site is available by using your favorite Internet browser to attach to:

www.microchip.com

The ﬁle transfer site is available by using an FTP service to connect to:

ftp.mchip.com/biz/mchip

The web site and ﬁle transfer site provide a v ariety of services. Users may download ﬁles for the latest Development Tools, Data Sheets, Application Notes, User's Guides, Articles and Sample Programs. A variety of Microchip speciﬁc business information is also available, including listings of Microchip sales ofﬁces, distributors and factory representatives. Other data available for consideration is:

• Latest Microchip Press Releases

• Technical Support Section with Frequently Asked Questions

• Design Tips

• Device Errata

• Job Postings

• Microchip Consultant Program Member Listing

• Links to other useful web sites related to Microchip Products

Connecting to the Microchip BBS

Connect worldwide to the Microchip BBS using either the Internet or the CompuServe



communications net-

work.

Internet:

You can telnet or ftp to the Microchip BBS at the address:

mchipbbs.microchip.com

CompuServe Communications Network:

When using the BBS via the Compuserve Network, in most cases, a local call is your only expense . The Microchip BBS connection does not use CompuServe membership services, therefore you do not need CompuServe membership to join Microchip's BBS. There is no charge for connecting to the Microchip BBS.

The procedure to connect will vary slightly from country to country. Please check with your local CompuServe agent for details if you have a problem. CompuServe service allow multiple users various baud rates depending on the local point of access.

The following connect procedure applies in most locations.

1. Set your modem to 8-bit, No parity, and One stop (8N1). This is not the normal CompuServe setting which is 7E1.

2. Dial your local CompuServe access number.

3. Depress the <Enter> key and a garbage string will appear because CompuServe is expecting a 7E1 setting.

4. Type +, depress the <Enter> key and “Host Name:” will appear.

5. Type MCHIPBBS, depress the <Enter> key and you will be connected to the Microchip BBS.

In the United States, to ﬁnd the CompuServe phone number closest to you, set your modem to 7E1 and dial (800) 848-4480 for 300-2400 baud or (800) 331-7166 for 9600-14400 baud connection. After the system responds with “Host Name:”, type NETWORK, depress the <Enter> key and follow CompuServe's directions.

For voice information (or calling from overseas), you may call (614) 723-1550 for your local CompuServe number.

Microchip regularly uses the Microchip BBS to distribute technical information, application notes, source code, errata sheets, bug reports, and interim patches for Microchip systems software products. For each SIG, a moderator monitors, scans, and approves or disapproves ﬁles submitted to the SIG. No executable ﬁles are accepted from the user community in general to limit the spread of computer viruses.

Systems Information and Upgrade Hot Line

The Systems Information and Upgrade Line provides system users a listing of the latest versions of all of Microchip's development systems software products. Plus, this line provides information on how customers can receive any currently available upgrade kits.The Hot Line Numbers are:

1-800-755-2345 for U.S . and most of Canada, and 1-602-786-7302 for the rest of the world.

Trademarks: The Microchip name, logo, PIC, PICSTART, PICMASTER, and are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries.

Flex

ROM, MPLAB, PRO MATE, and

fuzzy

LAB, are trademarks and SQTP is a service mark of Microchip in the U.S.A.

fuzzy

TECH is a registered trademark of Inform Software Corporation. IBM, IBM PC-AT are registered trademarks of International Business Machines Corp. Pentium is a trademark of Intel Corporation. Windows is a trademark and MS-DOS, Microsoft Windows are registered trademarks of Microsoft Corporation. CompuServe is a registered trademark of CompuServe Incorporated.

All other trademarks mentioned herein are the property of their respective companies.

PIC12C5XX

DS40139B-page 72  1997 Microchip Technology Inc.

READER RESPONSE

It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please FAX your comments to the Technical Publications Manager at (602) 786-7578.

Please list the following information, and use this outline to provide us with your comments about this Data Sheet.

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?

5. What deletions from the data sheet could be made without affecting the overall usefulness?

6. Is there any incorrect or misleading information (what and where)?

7. How would you improve this document?

8. How would you improve our software, systems, and silicon products?

To:

Technical Publications Manager

RE: Reader Response

Total Pages Sent

From:

Name Company

Address City / State / ZIP / Country

Telephone: (_______) _________ - _________

Application (optional): Would you like a reply? Y N

Device:

Literature Number:

Questions:

FAX: (______) _________ - _________

DS40139B

PIC12C5XX

 1997 Microchip Technology Inc. Preliminary DS40139B-page 73

PIC12C5XX

PIC12C5XX PRODUCT IDENTIFICATION SYSTEM

Please contact your local sales ofﬁce for exact ordering procedures.

Pattern: Special Requirements

Package: SM = 208 mil SOIC

P = 300 mil PDIP JW = 300 mil Windowed Ceramic Side Brazed

Temperature Range:

- = 0°C to +70°C I = -40°C to +85°C E = -40°C to +125°C

Frequency Range:

04 = 4 MHz

Device PIC12C508

PIC12C509 PIC12C508T (Tape & reel for SOIC only) PIC12C509T (Tape & reel for SOIC only)

PART NO. -XX X /XX XXX

Examples

a) PIC12C508-04/P

Commercial Temp., PDIP Package, 4 MHz, normal V

DD limits

b) PIC12C508-04I/SM

Industrial Temp., SOIC package, 4 MHz, normal V

DD limits

c) PIC12C509-04I/P

Industrial Temp., PDIP package, 4 MHz, normal V

DD limits

Sales and Support

Products supported by a preliminary Data Sheet may possibly have an errata sheet describing minor operational differences and recommended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:

Your local Microchip sales ofﬁce (see below)

The Microchip Corporate Literature Center U.S. FAX: (602) 786-7277 The Microchip’s Bulletin Board, via your local CompuServe number (CompuServe membership NOT required).

Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using. For latest version information and upgrade kits for Microchip Development Tools, please call 1-800-755-2345 or 1-602-786-7302.

PIC12C5XX

DS40139B-page 74 Preliminary  1997 Microchip Technology Inc.

NOTES:

 1997 Microchip Technology Inc. Preliminary DS40139B-page 75

PIC12C5XX

NOTES:

WORLDWIDE SALES & SERVICE

Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip’s products as critical components in life support systems is not authorized except with express written approval by Microchip . No licenses are conveyed, implicitly or otherwise, under an y intellectual property rights. The Microchip logo and name are registered trademarks of Microchip Technology Inc. All rights reserved. All other trademarks mentioned herein are the property of their respective companies.

DS40139B - page 76  1997 Microchip Technology Inc.

AMERICAS

Corporate Ofﬁce

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Technical Support:

602 786-7627

Web:

http://www.microchip.com

Atlanta

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3/24/97

Microchip Technology Inc PIC12C508-04E-P, PIC12C508-04E-SM, PIC12C508-04I-JW, PIC12C508-04I-P, PIC12C508-04I-SM Datasheet

Specifications and Main Features

Frequently Asked Questions

User Manual