MICROCHIP PIC16C84 Technical data

Download



8-bit CMOS EEPROM Microcontroller

High Performance RISC CPU Features:

•Only 35 single word instructions to learn

•All instructions single cycle (400 ns @ 10 MHz) except for program branches which are two-cycle

•Operating speed:DC - 10 MHz clock input

DC - 400 ns instruction cycle

•14-bit wide instructions

•8-bit wide data path

•1K x 14 EEPROM program memory

•36 x 8 general purpose registers (SRAM)

•64 x 8 on-chip EEPROM data memory

•15 special function hardware registers

•Eight-level deep hardware stack

•Direct, indirect and relative addressing modes

•Four interrupt sources:

-External RB0/INT pin

-TMR0 timer overﬂow

-PORTB<7:4> interrupt on change

-Data EEPROM write complete

•1,000,000 data memory EEPROM ERASE/WRITE cycles

•EEPROM Data Retention > 40 years

Peripheral Features:

•13 I/O pins with individual direction control

•High current sink/source for direct LED drive

-25 mA sink max. per pin

-20 mA source max. per pin

•TMR0: 8-bit timer/counter with 8-bit programmable prescaler

Special Microcontroller Features:

•Power-on Reset (POR)

•Power-up Timer (PWRT)

•Oscillator Start-up Timer (OST)

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

•Code protection

•Power saving SLEEP mode

•Selectable oscillator options

•Serial In-System Programming - via two pins

PIC16C84

Pin Diagram

PDIP, SOIC

RA2 RA3

RA4/T0CKI

MCLR

VSS

RB0/INT

RB1 RB2 RB3

•1 2 3 4 5 6 7 8 9

18 17

PIC16C84

16 15 14 13 12 11 10

CMOS Technology:

•Low-power, high-speed CMOS EEPROM technology

•Fully static design

•Wide operating voltage range:

-Commercial: 2.0V to 6.0V

-Industrial: 2.0V to 6.0V

•Low power consumption:

-< 2 mA typical @ 5V, 4 MHz

-60 µ A typical @ 2V, 32 kHz

-26 µ A typical standby current @ 2V

RA1 RA0 OSC1/CLKIN OSC2/CLKOUT V

RB7 RB6 RB5 RB4

1997 Microchip Technology Inc. DS30445C-page 1



PIC16C84

Table of Contents

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

2.0 PIC16C84 Device Varieties ........................................................................................................................................................... 5

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

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

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

6.0 Timer0 Module and TMR0 Register............................................................................................................................................. 25

7.0 Data EEPROM Memory............................................................................................................................................................... 31

8.0 Special Features of the CPU ....................................................................................................................................................... 35

9.0 Instruction Set Summary.............................................................................................................................................................. 51

10.0 Development Support.................................................................................................................................................................. 67

11.0 Electrical Characteristics for PIC16C84....................................................................................................................................... 71

12.0 DC & AC Characteristics Graphs/Tables for PIC16C84.............................................................................................................. 83

13.0 Packaging Information................................................................................................................................................................. 97

Appendix A: Feature Improvements - From PIC16C5X To PIC16C84............................................................................................ 99

Appendix B: Code Compatibility - from PIC16C5X to PIC16C84.................................................................................................... 99

Appendix C: What’s New In This Data Sheet................................................................................................................................. 100

Appendix D: What’s Changed In This Data Sheet......................................................................................................................... 100

Appendix E: Conversion Considerations - PIC16C84 to PIC16F83/F84 And PIC16CR83/CR84.................................................. 101

Index .................................................................................................................................................................................................. 103

On-Line Support................................................................................................................................................................................. 105

PIC16C84 Product Identification System........................................................................................................................................... 107

Sales and Support.............................................................................................................................................................................. 107

To Our Valued Customers

We constantly strive to improve the quality of all our products and documentation. We have spent a great deal 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.

DS30445C-page 2

1997 Microchip Technology Inc.



PIC16C84

1.0 GENERAL DESCRIPTION

The PIC16C84 is a low-cost, high-performance, CMOS, fully-static, 8-bit microcontroller.

All PIC16/17 microcontrollers employ an advanced RISC architecture. PIC16CXX devices have enhanced core features, eight-le vel deep stack, and multiple internal and external interrupt sources. The separate instruction and data buses of the Harvard architecture allow a 14-bit wide instruction word with a separate 8-bit wide data bus. The two stage instruction pipeline allows all instructions to execute in a single cycle, except for program branches (which require two cycles). A total of 35 instructions (reduced instruction set) are available. Additionally, a large register set is used to achieve a very high performance level.

PIC16CXX microcontrollers typically achieve a 2:1 code compression and up to a 2:1 speed improvement (at 10 MHz) over other 8-bit microcontrollers in their class.

The PIC16C84 has 36 bytes of RAM, 64 bytes of Data EEPROM memory, and 13 I/O pins. A timer/counter is also available.

The PIC16CXX family has special features to reduce external components, thus reducing cost, enhancing system reliability and reducing power consumption. There are four oscillator options, of which the single pin RC oscillator provides a low-cost solution, the LP oscillator minimizes power consumption, XT is a standard crystal, and the HS is for High Speed crystals. The SLEEP (power-down) mode offers power savings. The user can wake the chip from sleep through sev er al external and internal interrupts and resets.

A highly reliable Watchdog Timer with its own on-chip RC oscillator provides protection against software lockup.

The PIC16C84 EEPROM program memory allows the same device package to be used for prototyping and production. In-circuit reprogrammability allows the code to be updated without the device being removed from the end application. This is useful in the development of many applications where the device may not be easily accessible, but the prototypes may require code updates. This is also useful for remote applications where the code may need to be updated (such as rate information).

Table 1-1 lists the features of the PIC16C84. A simpliﬁed block diagram of the PIC16C84 is shown in Figure 3-1.

The PIC16C84 ﬁts perfectly in applications ranging from high speed automotive and appliance motor control to low-power remote sensors, electronic locks, security devices and smart cards. The EEPROM technology makes customization of application programs (transmitter codes, motor speeds, receiver frequencies, security codes, etc.) extremely fast and convenient. The small footprint packages make this microcontroller series perfect for all applications with space limitations. Low cost, low power, high performance, ease of use and I/O ﬂexibility make the PIC16C84 very versatile even in areas where no microcontroller use has been considered before (e.g., timer functions, serial communication, capture and compare, PWM functions and co-processor applications).

The serial in-system programming feature (via two pins) offers ﬂexibility of customizing the product after complete assembly and testing. This feature can be used to serialize a product, store calibration data, or program the device with the current ﬁrmware before shipping.

1.1 F

Those users familiar with the PIC16C5X family of microcontrollers will realize that this is an enhanced version of the PIC16C5X architecture. Please refer to Appendix A for a detailed list of enhancements. Code written for PIC16C5X can be easily ported to the PIC16C84 (Appendix B).

1.2 De

The PIC16CXX family is supported by a full-featured macro assembler, a software simulator, an in-circuit emulator, a low-cost development programmer and a full-featured programmer. A “C” compiler and fuzzy logic support tools are also available.

amily and Upward Compatibility

velopment Support

1997 Microchip Technology Inc. DS30445C-page 3



PIC16C84

TABLE 1-1 PIC16C8X FAMILY OF DEVICES

PIC16F83

Clock

Memory

Peripherals Timer Module(s) TMR0 TMR0 TMR0 TMR0

Features

All PICmicro™ Family devices have P o w er-on Reset, selectable W atchdog Timer , selectable code protect and high I/O current capability. All PIC16C8X Family devices use serial programming with clock pin RB6 and data pin RB7.

Maximum Frequency of Operation (MHz)

Flash Program Memory 512 — 1K — EEPROM Program Memory — — — — ROM Program Memory — 512 — 1K Data Memory (bytes) 36 36 68 68 Data EEPROM (bytes) 64 64 64 64

Interrupt Sources 4 4 4 4 I/O Pins 13 13 13 13 Voltage Range (Volts) 2.0-6.0 2.0-6.0 2.0-6.0 2.0-6.0 Packages 18-pin DIP,

10 10 10 10

SOIC

PIC16CR83 PIC16F84 PIC16CR84

18-pin DIP, SOIC

DS30445C-page 4

1997 Microchip Technology Inc.



2.0 PIC16C84 DEVICE VARIETIES

A variety of frequency ranges and packaging options are available . Depending on application and production requirements the proper device option can be selected using the information in this section. When placing orders, please use the “PIC16C84 Product Identiﬁcation System” at the back of this data sheet to specify the correct part number.

There are two device “types” as indicated in the device number.

1. C , as in PIC16 C 84. These devices have EEPROM program memory and operate over the standard voltage range.

2. LC , as in PIC16 LC 84. These devices have EEPROM program memory and operate over an extended voltage range.

When discussing memory maps and other architectural features, the use of C also implies the LC versions.

PIC16C84

2.1 Electricall

These devices are offered in the lower cost plastic package, even though the device can be erased and reprogrammed. This allows the same device to be used for prototype development and pilot programs as well as production.

A further advantage of the electrically erasable version is that they can be erased and reprogrammed in-circuit, or by device programmers, such as Microchip's PICSTART



Plus or PRO MATE

y Erasable Devices



II programmers.

1997 Microchip Technology Inc. DS30445C-page 5

PIC16C84

NOTES:



DS30445C-page 6

1997 Microchip Technology Inc.



PIC16C84

3.0 ARCHITECTURAL OVERVIEW

The high performance of the PIC16CXX family can be attributed to a number of architectural features commonly found in RISC microprocessors. To begin with, the PIC16CXX uses a Harvard architecture. This architecture has the program and data accessed from separate memories. So the device has a program memory bus and a data memory bus. This improves bandwidth over traditional von Neumann architecture where program and data are fetched from the same memory (accesses over the same bus). Separating program and data memory further allows instructions to be sized differently than the 8-bit wide data word. PIC16CXX opcodes are 14-bits wide, enabling single word instructions. The full 14-bit wide program memory bus fetches a 14-bit instruction in a single cycle. A twostage pipeline overlaps fetch and execution of instructions (Example 3-1). Consequently , all instructions e xecute in a single cycle (400 ns @ 10 MHz) except for program branches.

The PIC16C84 addresses 1K x 14 program memory. All program memory is internal.

PIC16CXX devices can directly or indirectly address its register ﬁles or data memory. All special function registers including the program counter are mapped in the data memory. An orthogonal (symmetrical) instruction set that makes it possible to carry out any operation on any register using any addressing mode. This symmetrical nature and lack of ‘special optimal situations’ make programming with the PIC16CXX simple yet efﬁcient. In addition, the learning curve is reduced signiﬁcantly.

The PIC16C84 has 36 x 8 SRAM and 64 x 8 EEPROM data memory.

PIC16CXX devices contain an 8-bit ALU and working register. The ALU is a general pur pose ar ithmetic 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 working register (W register), and the other operand is 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 borro respectively, in subtraction. See the SUBLW and SUBWF instructions for examples.

A simpliﬁed block diagram for the PIC16C84 is shown in Figure 3-1, its corresponding pin description is shown in Table 3-1.

w and digit borrow out bit,

1997 Microchip Technology Inc. DS30445C-page 7

PIC16C84

FIGURE 3-1: PIC16C84 BLOCK DIAGRAM



EEPROM

Program Memory

1K x 14

Program

Bus 14

Instruction reg

Instruction

Decode &

Control

Timing

Generation

Program Counter

8 Level Stack

Power-up

Timer

Oscillator

Start-up Timer

Power-on

Reset

Watchdog

Timer

(13-bit)

Direct Addr

Data Bus 8

RAM

File Registers

36 x 8

RAM Addr

Addr Mux

FSR reg

STATUS reg

MUX

ALU

W reg

Indirect

Addr

EEPROM Data Memory

EEDATA

TMR0

I/O Ports

EEPROM

Data Memory

64 x 8

EEADR

RA4/T0CKI

RA3:RA0

RB7:RB1

OSC2/CLKOUT

OSC1/CLKIN

MCLR

RB0/INT

VDD, VSS

DS30445C-page 8

1997 Microchip Technology Inc.



PIC16C84

TABLE 3-1 PIC16C8X PINOUT DESCRIPTION

DIP

Pin Name

OSC1/CLKIN 16 16 I ST/CMOS OSC2/CLKOUT 15 15 O — Oscillator crystal output. Connects to crystal or resonator in crys-

MCLR

RA0 17 17 I/O TTL RA1 18 18 I/O TTL RA2 1 1 I/O TTL RA3 2 2 I/O TTL

RA4/T0CKI 3 3 I/O ST Can also be selected to be the clock input to the TMR0 timer/

RB0/INT 6 6 I/O TTL RB0/INT can also be selected as an external interrupt pin. RB1 7 7 I/O TTL RB2 8 8 I/O TTL RB3 9 9 I/O TTL RB4 10 10 I/O TTL Interrupt on change pin. RB5 11 11 I/O TTL Interrupt on change pin. RB6 12 12 I/O TTL/ST RB7 13 13 I/O TTL/ST V

Legend: I= input O = output I/O = Input/Output P = power

Note 1: This buffer is a Schmitt Trigger input when conﬁgured in RC oscillator mode and a CMOS input otherwise.

This buffer is a Schmitt Trigger input when used in serial programming mode.

SOIC

No.

14 14 P — Positive supply for logic and I/O pins.

— = Not used TTL = TTL input ST = Schmitt Trigger input

No.

4 4 I/P ST Master clear (reset) input/programming voltage input. This pin is an

5 5 P — Ground reference for logic and I/O pins.

I/O/P Type

Buffer

Type

(2) (2)

Description

(1)

Oscillator crystal input/external clock source input.

tal oscillator mode. In RC mode , OSC2 pin outputs CLK OUT which has 1/4 the frequency of OSC1, and denotes the instruction cycle rate.

active low reset to the device. PORTA is a bi-directional I/O port.

counter. Output is open drain type.

PORTB is a bi-directional I/O port. PORTB can be software programmed for internal weak pull-up on all inputs.

Interrupt on change pin. Serial programming clock. Interrupt on change pin. Serial programming data.

1997 Microchip Technology Inc. DS30445C-page 9

PIC16C84



3.1 Clocking Scheme/Instruction Cycle

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

FIGURE 3-2: CLOCK/INSTRUCTION CYCLE

Q2 Q3 Q4

OSC1

Q1 Q2 Q3

Q4 PC

OSC2/CLKOUT

(RC mode)

Fetch INST (PC)

Execute INST (PC-1)

Execute INST (PC)

3.2 Instruction Flow/Pipelining

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

Q2 Q3 Q4

PC+1 PC+2

Fetch INST (PC+1)

Q2 Q3 Q4

Fetch INST (PC+2)

Execute INST (PC+1)

Internal phase clock

EXAMPLE 3-1: INSTRUCTION PIPELINE FLOW

1. MOVLW 55h

2. MOVWF PORTB

3. CALL SUB_1

4. BSF PORTA, BIT3

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.

DS30445C-page 10

Fetch 1 Execute 1

Fetch 2 Execute 2

Fetch 3 Execute 3

Fetch 4 Flush

Fetch SUB_1 Execute SUB_1

1997 Microchip Technology Inc.



PIC16C84

4.0 MEMORY ORGANIZATION

There are two memory blocks in the PIC16C84. These are the program memory and the data memory. Each block has its own b us, so that access to each b lock can occur during the same oscillator cycle.

The data memory can further be broken down into the general purpose RAM and the Special Function Registers (SFRs). The operation of the SFRs that control the “core” are described here. The SFRs used to control the peripheral modules are described in the section discussing each individual peripheral module.

The data memory area also contains the data EEPROM memory . This memory is not directly mapped into the data memory, but is indirectly mapped. That is an indirect address pointer speciﬁes the address of the data EEPROM memory to read/write. The 64 bytes of data EEPROM memory have the address range 0h-3Fh. More details on the EEPROM memory can be found in Section 7.0.

4.1 Pr

The PIC16CXX has a 13-bit program counter capable of addressing an 8K x 14 program memory space. For the PIC16C84, only the ﬁrst 1K x 14 (0000h-03FFh) are physically implemented (Figure 4-1). Accessing a location above the physically implemented address will cause a wraparound. For example, locations 20h, 420h, 820h, C20h, 1020h, 1420h, 1820h, and 1C20h will be the same instruction.

The reset vector is at 0000h and the interrupt vector is at 0004h.

ogram Memory Organization

FIGURE 4-1: PROGRAM MEMORY MAP

AND STACK

PC<12:0>

CALL, RETURN RETFIE, RETLW

Stack Level 1

Stack Level 8

Reset Vector

Peripheral Interrupt Vector

Space

User Memory

•

0000h

0004h

3FFh

1FFFh

1997 Microchip Technology Inc. DS30445C-page 11

PIC16C84



4.2 Data Memory Organization

The data memory is partitioned into two areas. The ﬁrst is the Special Function Registers (SFR) area, while the second is the General Purpose Registers (GPR) area. The SFRs control the operation of the device.

Portions of data memory are banked. This is for both the SFR area and the GPR area. The GPR area is banked to allow greater than 116 bytes of general purpose RAM. The banked areas of the SFR are f or the registers that control the peripheral functions. Banking requires the use of control bits for bank selection. These control bits are located in the STATUS Register. Figure 4-2 shows the data memory map organization.

Instructions MOVWF and MOVF can move values from the W register to any location in the register ﬁle (“F”), and vice-versa.

The entire data memory can be accessed either directly using the absolute address of each register ﬁle or indirectly through the File Select Register (FSR) (Section 4.5). Indirect addressing uses the present value of the RP1:RP0 bits for access into the banked areas of data memory.

Data memory is partitioned into two banks which contain the general purpose registers and the special function registers. Bank 0 is selected by clearing the RP0 bit (STATUS<5>). Setting the RP0 bit selects Bank 1. Each Bank extends up to 7Fh (128 bytes). The ﬁrst twelve locations of each Bank are reserved for the Special Function Registers. The remainder are General Purpose Registers implemented as static RAM.

FIGURE 4-2: REGISTER FILE MAP

File Address

00h 01h

02h 03h

04h 05h 06h 07h

08h

09h 0Ah 0Bh

0Ch

2Fh

30h

Indirect addr.

TMR0 OPTION

STATUS

PORTA PORTB

EEDATA

EEADR PCLATH INTCON

General Purpose

registers

(SRAM)

(1)

PCL

FSR

Indirect addr.

PCL

STATUS

FSR TRISA TRISB

EECON1

EECON2

PCLATH INTCON

Mapped

(accesses)

in Bank 0

File Address

(1)

80h 81h

82h 83h

84h 85h 86h 87h

88h 89h

8Ah 8Bh

8Ch

AFh B0h

4.2.1 GENERAL PURPOSE REGISTER FILE All devices have some amount of General Purpose

Register (GPR) area. Each GPR is 8 bits wide and is accessed either directly or indirectly through the FSR (Section 4.5).

The GPR addresses in bank 1 are mapped to addresses in bank 0. As an example, addressing location 0Ch or 8Ch will access the same GPR.

4.2.2 SPECIAL FUNCTION REGISTERS The Special Function Registers (Figure 4-2 and

Table 4-1) are used by the CPU and Peripheral functions to control the device operation. These registers are static RAM.

The special function registers can be classiﬁed into two sets, core and peripheral. Those 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 that speciﬁc feature.

7Fh

Unimplemented data memory location; read as '0'.

Note 1: Not a physical register.

Bank 0

Bank 1

FFh

DS30445C-page 12

1997 Microchip Technology Inc.

TABLE 4-1 REGISTER FILE SUMMARY

PIC16C84



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

Bank 0

00h INDF Uses contents of FSR to address data memory (not a physical register) 01h TMR0 8-bit real-time clock/counter 02h PCL Low order 8 bits of the Program Counter (PC)

OPTION_

REG

(2)

IRP RP1 RP0

— — — RA4/T0CKI RA3 RA2 RA1 RA0 ---x xxxx ---u uuuu

— — — Write buffer for upper 5 bits of the PC

RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0

(2)

IRP RP1 RP0 TO PD Z DC C 0001 1xxx 000q quuu

— — — PORTA data direction register ---1 1111 ---1 1111

Unimplemented location, read as '0' ---- ---- ---- ----

03h STATUS 04h FSR Indirect data memory address pointer 0 05h PORTA 06h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0/INT xxxx xxxx uuuu uuuu 07h Unimplemented location, read as '0' ---- ---- ---- ---08h EEDATA EEPROM data register xxxx xxxx uuuu uuuu 09h EEADR EEPROM address register xxxx xxxx uuuu uuuu

0Ah PCLATH 0Bh INTCON GIE EEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u

80h INDF Uses contents of FSR to address data memory (not a physical register) ---- ---- ---- ----

81h 82h PCL Low order 8 bits of Program Counter (PC) 0000 0000 0000 0000

83h STATUS 84h FSR Indirect data memory address pointer 0 xxxx xxxx uuuu uuuu 85h TRISA 86h TRISB PORTB data direction register 1111 1111 1111 1111

87h 88h EECON1 — — — EEIF WRERR WREN WR RD ---0 x000 ---0 q000

89h EECON2 EEPROM control register 2 (not a physical register) ---- ---- ---- ---0Ah PCLATH — — — Write buffer for upper 5 bits of the PC

0Bh INTCON GIE EEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u

PD Z DC C

(1)

Bank 1

(1)

Value on

Power-on

Reset

---- ---- ---- ---xxxx xxxx uuuu uuuu 0000 0000 0000 0000

0001 1xxx 000q quuu xxxx xxxx uuuu uuuu

---0 0000 ---0 0000

1111 1111 1111 1111

---0 0000 ---0 0000

Value on all

other resets

(Note3)

Legend: x = unknown, u = unchanged. - = unimplemented read as '0', q = value depends on condition. Note 1: The upper byte of the program counter is not directly accessible. PCLATH is a slave register for PC<12:8>. The contents

of PCLATH can be transferred to the upper b yte of the program counter, but the contents of PC<12:8> is nev er transf erred to PCLATH.

2: The T

O and PD status bits in the STATUS register are not affected by a MCLR reset.

3: Other (non power-up) resets include: external reset through MCLR and the Watchdog Timer Reset.

1997 Microchip Technology Inc. DS30445C-page 13

PIC16C84

4.2.2.1 STATUS REGISTER The STATUS register contains the arithmetic status of

the ALU, the RESET status and the bank select bit for data memory.

As with any register, the STATUS register can be the destination for any instruction. If the STA TUS 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 device logic. Furthermore, the T 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).

O and PD bits are not writable.

Only the BCF, BSF, SWAPF and MOVWF instructions should be used to alter the ST ATUS register (T ab le 9-2) because these instructions do not affect any status bit.

Note 1: The IRP and RP1 bits (ST ATUS<7:6>) are

Note 2: The C and DC bits operate as a borro

Note 3: When the STATUS register is the

FIGURE 4-3: STATUS REGISTER (ADDRESS 03h, 83h)

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

IRP RP1 RP0 bit7 bit0

bit 7: IRP: Register Bank Select bit (used for indirect addressing)

0 = Bank 0, 1 (00h - FFh) 1 = Bank 2, 3 (100h - 1FFh) The IRP bit is not used by the PIC16C8X. IRP should be maintained clear.

bit 6-5: RP1:RP0: Register Bank Select bits (used for direct addressing)

00 = Bank 0 (00h - 7Fh) 01 = Bank 1 (80h - FFh) 10 = Bank 2 (100h - 17Fh) 11 = Bank 3 (180h - 1FFh) Each bank is 128 bytes. Only bit RP0 is used by the PIC16C8X. RP1 should be maintained clear.

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/borro

1 = A carry-out from the 4th low order bit of the result occurred 0 = No carry-out from the 4th low order bit of the result

bit 0: C: Carry/borro

1 = A carry-out from the most signiﬁcant bit of the result occurred 0 = No carry-out from the most signiﬁcant bit of the result occurred Note: For borro

the second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high or low order bit of the source register.

w bit (for ADDWF and ADDLW instructions)

TO PD

w bit (for ADDWF and ADDLW instructions) (For borrow the polarity is reversed)

w the polarity is reversed. A subtraction is executed by adding the two’s complement of

Z DC C R = Readable bit

not used by the PIC16C84 and should be programmed as cleared. Use of these bits as general purpose R/W bits is NOT recommended, since this may affect upward compatibility with future products.

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

destination for an instruction that affects the Z, DC or C bits, then the write to these three bits is disabled. The speciﬁed bit(s) will be updated according to device logic

W = Writable bit U = Unimplemented bit, read as ‘0’

- n = Value at POR reset

DS30445C-page 14  1997 Microchip Technology Inc.

4.2.2.2 OPTION_REG REGISTER The OPTION_REG register is a readable and writable

Note: When the prescaler is assigned to

the WDT (PSA = '1'), TMR0 has a 1:1 prescaler assignment.

TMR0, and the weak pull-ups on PORTB.

FIGURE 4-4: OPTION_REG REGISTER (ADDRESS 81h)

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 R = Readable bit

bit7 bit0

bit 7: RBPU: PORTB Pull-up Enable bit

1 = PORTB pull-ups are disabled 0 = PORTB pull-ups are enabled (by individual port latch values)

bit 6: INTEDG: Interrupt Edge Select bit

1 = Interrupt on rising edge of RB0/INT pin 0 = Interrupt on falling edge of RB0/INT pin

bit 5: T0CS: TMR0 Clock Source Select bit

1 = Transition on RA4/T0CKI pin 0 = Internal instruction cycle clock (CLKOUT)

bit 4: T0SE: TMR0 Source Edge Select bit

1 = Increment on high-to-low transition on RA4/T0CKI pin 0 = Increment on low-to-high transition on RA4/T0CKI pin

bit 3: PSA: Prescaler Assignment bit

1 = Prescaler assigned to the WDT 0 = Prescaler assigned to TMR0

bit 2-0: PS2:PS0: Prescaler Rate Select bits

Bit Value TMR0 Rate WDT Rate

000 001 010 011 100 101 110 111

1 : 2 1 : 4 1 : 8 1 : 16 1 : 32 1 : 64 1 : 128 1 : 256

1 : 1 1 : 2 1 : 4 1 : 8 1 : 16 1 : 32 1 : 64 1 : 128

W = Writable bit U = Unimplemented bit,

read as ‘0’

- n = Value at POR reset

PIC16C84

 1997 Microchip Technology Inc. DS30445C-page 15

PIC16C84

4.2.2.3 INTCON REGISTER The INTCON register is a readable and writable

FIGURE 4-5: INTCON REGISTER (ADDRESS 0Bh, 8Bh)

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

GIE EEIE T0IE INTE RBIE T0IF INTF RBIF R = Readable bit

bit7 bit0

bit 7: GIE: Global Interrupt Enable bit

1 = Enables all un-masked interrupts 0 = Disables all interrupts

Note: For the operation of the interrupt structure, please refer to Section 8.5.

bit 6: EEIE: EE Write Complete Interrupt Enable bit

1 = Enables the EE write complete interrupt 0 = Disables the EE write complete interrupt

bit 5: T0IE: TMR0 Overﬂow Interrupt Enable bit

1 = Enables the TMR0 interrupt 0 = Disables the TMR0 interrupt

bit 4: INTE: RB0/INT Interrupt Enable bit

1 = Enables the RB0/INT interrupt 0 = Disables the RB0/INT interrupt

bit 3: RBIE: RB Port Change Interrupt Enable bit

1 = Enables the RB port change interrupt 0 = Disables the RB port change interrupt

bit 2: T0IF: TMR0 overﬂow interrupt ﬂag bit

1 = TMR0 has overﬂowed (must be cleared in software) 0 = TMR0 did not overﬂow

bit 1: INTF: RB0/INT Interrupt Flag bit

1 = The RB0/INT interrupt occurred 0 = The RB0/INT interrupt did not occur

bit 0: RBIF: RB Port Change Interrupt Flag bit

1 = When at least one of the RB7:RB4 pins changed state (must be cleared in software) 0 = None of the RB7:RB4 pins have changed state

Note: Interrupt ﬂag bits get set when an interrupt

condition occurs regardless of the state of its corresponding enable bit or the global enable bit, GIE (INTCON<7>).

W = Writable bit U = Unimplemented bit,

- n = Value at POR reset

read as ‘0’

DS30445C-page 16  1997 Microchip Technology Inc.

PIC16C84

4.3 Program Counter: PCL and PCLATH

The Program Counter (PC) is 13-bits wide. The low byte is the PCL register, which is a readable and writable register. The high byte of the PC (PC<12:8>) is not directly readable nor writable and comes from the PCLATH register . The PCLATH (PC latch high) register is a holding register for PC<12:8>. The contents of PCLATH are transferred to the upper byte of the program counter when the PC is loaded with a new value. This occurs during a CALL, GOTO or a wr ite to PCL. The high bits of PC are loaded from PCLATH as shown in Figure 4-6.

FIGURE 4-6: LOADING OF PC IN

DIFFERENT SITUATIONS

PCH PCL

12 8 7 0

PCLATH<4:0>

PCLATH

PCH PCL

12 11 10 0

8 7

PCLATH<4:3>

PCLATH

4.3.1 COMPUTED GOTO A computed GOT O is accomplished b y adding an offset

to the program counter (ADDWF PCL). When doing a table read using a computed GOTO method, care should be exercised if the table location crosses a PCL memory boundary (each 256 word block). Refer to the application note

“Implementing a Table Read”

INST with PCL as dest

ALU result

GOTO, CALL

Opcode <10:0>

(AN556).

Note: The PIC16C84 ignores the PCLATH<4:3>

bits, which are used for program memory pages 1, 2 and 3 (0800h - 1FFFh). The use of PCLATH<4:3> as general purpose R/W bits is not recommended since this may affect upward compatibility with future products.

4.4 Stack

The PIC16C84 has an 8 deep x 13-bit wide hardware stack (Figure 4-1). The stack space is not part of either program or data space and the stack pointer is not readable or writable.

The entire 13-bit PC is “pushed” onto the stack when a CALL instruction is executed or an interrupt is acknowledged. The stack is “popped” in the ev ent of a RETURN, RETLW or a RETFIE instruction execution. PCLATH is not affected by a push or a pop operation.

Note: There are no instruction mnemonics called

push or pop. These are actions that occur from the execution of the CALL, RETURN, RETLW, and RETFIE instructions, or the vectoring to an interrupt address.

The stack operates as a circular buffer. That is, after the stack has been pushed eight times, the ninth push ov erwrites the value that was stored from the ﬁrst push. The tenth push overwrites the second push (and so on).

If the stack is effectively popped nine times, the PC value is the same as the value from the ﬁrst pop.

Note: There are no status bits to indicate stack

overﬂow or stack underﬂow conditions.

4.3.2 PROGRAM MEMORY PAGING The PIC16C84 has 1K of program memory. The CALL

and GOTO instructions have an 11-bit address range. This 11-bit address range allows a branch within a 2K program memory page size. For future PIC16CXX program memory expansion, there must be another two bits to specify the program memory page. These paging bits come from the PCLATH<4:3> bits (Figure 4-6). When doing a CALL or a GOTO instruction, the user must ensure that these page bits (PCLATH<4:3>) are programmed to the desired program memory page. If a CALL instruction (or interrupt) is executed, the entire 13-bit PC is “pushed” onto the stack (see next section). Therefore, manipulation of the PCLATH<4:3> is not required for the return instructions (which “pops” the PC from the stack).

 1997 Microchip Technology Inc. DS30445C-page 17

PIC16C84

4.5 Indirect 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 05 contains the value 10h

• Register ﬁle 06 contains the value 0Ah

• Load the value 05 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 = 06)

• A read of the INDF 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).

FIGURE 4-7: DIRECT/INDIRECT ADDRESSING

Direct Addressing

RP1 RP0 6

from opcode

0 IRP 7 (FSR) 0

A simple program to clear RAM locations 20h-2Fh using indirect addressing is shown in Example 4-2.

EXAMPLE 4-2: HOW TO CLEAR RAM

USING INDIRECT ADDRESSING

movlw 0x20 ;initialize pointer movwf FSR ; to RAM NEXT clrf INDF ;clear INDF register incf FSR ;inc pointer btfss FSR,4 ;all done? goto NEXT ;NO, clear next CONTINUE : ;YES, continue

An effective 9-bit address is obtained b y concatenating the 8-bit FSR register and the IRP bit (STATUS<7>), as shown in Figure 4-7. However, IRP is not used in the PIC16C84.

Indirect Addressing

bank select location select

Data Memory

00 01 10 11

00h

not used

0Bh 0Ch

Addresses map back

to Bank 0

2Fh 30h

7Fh

Bank 0 Bank 1 Bank 2 Bank 3

bank select location select

00h

not used

7Fh

DS30445C-page 18  1997 Microchip Technology Inc.

PIC16C84

5.0 I/O PORTS

The PIC16C84 has two ports, PORTA and PORTB. Some port pins are multiplexed with an alternate function for other features on the device.

5.1 PORTA and TRISA Registers

PORTA is a 5-bit wide latch. RA4 is a Schmitt Trigger input and an open drain output. All other RA port pins have TTL input levels and full CMOS output drivers. All pins have data direction bits (TRIS registers) which can conﬁgure these pins as output or input.

Setting a TRISA bit (=1) will make the corresponding PORTA pin an input, i.e., put the corresponding output driver in a hi-impedance mode. Clearing a TRISA bit (=0) will make the corresponding PORTA pin an output, i.e., put the contents of the output latch on the selected pin.

Reading the PORTA register reads the status of the pins whereas writing to it will write to the port latch. All write operations are read-modify-write operations. So a write to a port implies that the port pins are ﬁrst read, then this value is modiﬁed and written to the port data latch.

The RA4 pin is multiplexed with the TMR0 clock input.

FIGURE 5-1: BLOCK DIAGRAM OF PINS

RA3:RA0

Data bus

WR Port

WR TRIS

Data Latch

TRIS Latch

RD TRIS

Q D

VDD

VSS

TTL input buffer

I/O pin

EXAMPLE 5-1: INITIALIZING PORTA

CLRF PORTA ; Initialize PORTA by ; setting output ; data latches BSF STATUS, RP0 ; Select Bank 1 MOVLW 0x0F ; Value used to ; initialize data ; direction MOVWF TRISA ; Set RA<3:0> as inputs ; RA4 as outputs ; TRISA<7:5> are always ; read as '0'.

FIGURE 5-2: BLOCK DIAGRAM OF PIN RA4

Data bus

WR PORT

WR TRIS

RD PORT

TMR0 clock input

Note: I/O pin has protection diodes to V

Note: For crystal oscillator conﬁgurations

operating below 500 kHz, the device may generate a spurious internal Q-clock when PORTA<0> switches state. This does not occur with an external clock in RC mode. To avoid this, the RA0 pin should be kept static, i.e. in input/output mode, pin RA0 should not be toggled.

Data Latch

TRIS Latch

RD TRIS

Schmitt Trigger input buffer

Q D

RA4 pin

SS only.

RD PORT

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

 1997 Microchip Technology Inc. DS30445C-page 19

PIC16C84

TABLE 5-1 PORTA FUNCTIONS

Name Bit0 Buffer Type Function

RA0 bit0 TTL Input/output RA1 bit1 TTL Input/output RA2 bit2 TTL Input/output RA3 bit3 TTL Input/output RA4/T0CKI bit4 ST Input/output or external clock input for TMR0.

Output is open drain type.

Legend: TTL = TTL input, ST = Schmitt Trigger input

TABLE 5-2 SUMMARY OF REGISTERS ASSOCIATED WITH PORTA

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

05h PORT A 85h TRISA — — — TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 ---1 1111 ---1 1111

Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are unimplemented, read as '0'

— — — RA4/T0CKI RA3 RA2 RA1 RA0 ---x xxxx ---u uuuu

Value on

Power-on

Reset

Value on all

other resets

DS30445C-page 20  1997 Microchip Technology Inc.

PIC16C84

5.2 PORTB and TRISB Registers

PORTB is an 8-bit wide bi-directional port. The corresponding data direction register is TRISB. A '1' on any bit in the TRISB register puts the corresponding output driver in a hi-impedance mode. A '0' on any bit in the TRISB register puts the contents of the output latch on the selected pin(s).

Each of the PORTB pins have a weak internal pull-up. A single control bit can turn on all the pull-ups. This is done by clearing the RBPU

(OPTION_REG<7>) bit. The weak pull-up is automatically turned off when the port pin is conﬁgured as an output. The pull-ups are disabled on a Power-on Reset.

Four of PORTB’s pins, RB7:RB4, have an interrupt on change feature. Only pins conﬁgured as inputs can cause this interrupt to occur (i.e., any RB7:RB4 pin conﬁgured as an output is excluded from the interrupt on change comparison). The pins value in input mode are compared with the old value latched on the last read of PORTB. The “mismatch” outputs of the pins are OR’ed together to generate the RB port change interrupt.

FIGURE 5-3: BLOCK DIAGRAM OF PINS

RB7:RB4

weak pull-up

I/O

TTL Input Buffer

(2)

RBPU

Data bus

WR Port

WR TRIS

(1)

Data Latch

TRIS Latch

This interrupt can wake the device from SLEEP. The user, in the interrupt service routine, can clear the interrupt in the following manner:

a) Read (or write) PORTB. This will end the mis-

match condition.

b) Clear ﬂag bit RBIF. A mismatch condition will continue to set the RBIF bit.

Reading PORTB will end the mismatch condition, and allow the RBIF bit to be cleared.

This interrupt on mismatch feature, together with software conﬁgurable pull-ups on these four pins allow easy interface to a key pad and make it possible for wake-up on key-depression (see AN552 in the Embedded Control Handbook).

Note 1: If a change on the I/O pin should occur

when a read operation of PORTB is being executed (start of the Q2 cycle), the RBIF interrupt ﬂag bit may not be set.

The interrupt on change feature is recommended for wake-up on key depression operation and operations where PORTB is only used for the interrupt on change feature. Polling of PORTB is not recommended while using the interrupt on change feature.

FIGURE 5-4: BLOCK DIAGRAM OF PINS

RB3:RB0

(1)

RBPU

Data bus

WR Port

WR TRIS

Data Latch

TRIS Latch

weak pull-up

I/O

TTL Input Buffer

(2)

RD TRIS

RD Port

Set RBIF

From other RB7:RB4 pins

Note 1: TRISB = '1' enables weak pull-up

2: I/O pins have diode protection to V

= '0' in the OPTION_REG register).

(if RBPU

Latch

Q D

DD and VSS.

RD Port

RD TRIS

RD Port

RB0/INT

Note 1: TRISB = '1' enables weak pull-up

2: I/O pins have diode protection to V

= '0' in the OPTION_REG register).

(if RBPU

Q D

RD Port

DD and VSS.

 1997 Microchip Technology Inc. DS30445C-page 21

PIC16C84

EXAMPLE 5-1: INITIALIZING PORTB

CLRF PORTB ; Initialize PORTB by ; setting output ; data latches BSF STATUS, RP0 ; Select Bank 1 MOVLW 0xCF ; Value used to ; initialize data ; direction MOVWF TRISB ; Set RB<3:0> as inputs ; RB<5:4> as outputs ; RB<7:6> as inputs

TABLE 5-3 PORTB FUNCTIONS

Name Bit Buffer Type I/O Consistency Function

RB0/INT bit0 TTL Input/output pin or external interrupt input. Internal software

programmable weak pull-up. RB1 bit1 TTL Input/output pin. Internal software programmable weak pull-up. RB2 bit2 TTL Input/output pin. Internal software programmable weak pull-up. RB3 bit3 TTL Input/output pin. Internal software programmable weak pull-up. RB4 bit4 TTL Input/output pin (with interrupt on change). Internal software programma-

ble weak pull-up. RB5 bit5 TTL Input/output pin (with interrupt on change). Internal software programma-

ble weak pull-up.

(1)

RB6 bit6 TTL/ST

RB7 bit7 TTL/ST

Legend: TTL = TTL input, ST = Schmitt Trigger. Note 1: This buffer is a Schmitt Trigger input when used in serial programming mode.

Input/output pin (with interrupt on change). Internal software programma-

ble weak pull-up. Serial programming clock.

(1)

Input/output pin (with interrupt on change). Internal software programma-

ble weak pull-up. Serial programming data.

TABLE 5-4 SUMMARY OF REGISTERS ASSOCIATED WITH PORTB

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

06h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0/INT xxxx xxxx uuuu uuuu 86h TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 1111 1111 1111 1111

81h

Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.

OPTION_

REG

RBPU

INTEDG T0CS T0SE PSA PS2 PS1 PS0

Value on

Power-on

Reset

1111 1111 1111 1111

Value on all

other resets

DS30445C-page 22  1997 Microchip Technology Inc.

PIC16C84

5.3 I/O Programming Considerations

5.3.1 BI-DIRECTIONAL I/O PORTS Any instruction which writes, operates internally as a

read followed by a write operation. The BCF and BSF instructions, for example, read the register into the CPU, ex ecute the bit operation and write the result back to the register. Caution must be used when these instructions are applied to a port with both inputs and outputs deﬁned. For example, a BSF operation on bit5 of PORTB will cause all eight bits of PORTB to be read into the CPU. Then the BSF operation takes place on bit5 and PORTB is written to the output latches. If another bit of PORTB is used as a bi-directional I/O pin (i.e., bit0) and it is deﬁned as an input at this time, the input signal present on the pin itself would be read into the CPU and rewritten to the data latch of this particular pin, 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 is unknown.

Reading the port register, reads the values of the port pins. Writing to the port register writes the value to the port latch. When using read-modify-write instructions (i.e., BCF, BSF , etc.) on a port, the value of the port pins is read, the desired operation is done to this value, and this value is then written to the port latch.

A pin actively outputting a Low or High should not be driven from external devices at the same time in order to change the level on this pin (“wired-or”, “wired-and”). The resulting high output current may damage the chip.

5.3.2 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-

5). Therefore , care must be e x ercised if a write follo wed by a read operation is carried out on the same I/O port. The sequence of instructions should be such that the pin voltage stabilizes (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.

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

EXAMPLE 5-1: READ-MODIFY-WRITE

INSTRUCTIONS ON AN I/O PORT

;Initial PORT settings: PORTB<7:4> Inputs ; PORTB<3:0> Outputs ;PORTB<7:6> have external pull-ups and are ;not connected to other circuitry ; ; PORT latch PORT pins ; ---------- -------- BCF PORTB, 7 ; 01pp ppp 11pp ppp BCF PORTB, 6 ; 10pp ppp 11pp ppp BSF STATUS, RP0 ; BCF TRISB, 7 ; 10pp ppp 11pp ppp BCF TRISB, 6 ; 10pp ppp 10pp ppp ; ;Note that the user may have expected the ;pin values to be 00pp ppp. The 2nd BCF ;caused RB7 to be latched as the pin value ;(high).

FIGURE 5-5: SUCCESSIVE I/O OPERATION

PC + 3

NOP

Note: This example shows a write to PORTB

followed by a read from PORTB. Note that: data setup time = (0.25TCY - TPD) where TCY = instruction cycle

TPD = propagation delay

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

NOP

Q1 Q2

Instruction

fetched

RB7:RB0

Instruction

executed

 1997 Microchip Technology Inc. DS30445C-page 23

MOVWF PORTB

PC PC + 1 PC + 2

write to PORTB

Q1 Q2

MOVF PORTB,W

MOVWF PORTB

write to PORTB

Q1 Q2

Port pin sampled here

TPD

MOVF PORTB,W

PIC16C84

NOTES:

DS30445C-page 24  1997 Microchip Technology Inc.

PIC16C84

6.0 TIMER0 MODULE AND TMR0 REGISTER

The Timer0 module timer/counter has the following features:

• 8-bit timer/counter

• Readable and writable

• 8-bit software programmable prescaler

• Internal or external clock select

• Interrupt on overﬂow from FFh to 00h

• Edge select for external clock

Timer mode is selected by clearing the T0CS bit (OPTION<5>). In timer mode, the Timer0 module (Figure 6-1) will increment every instruction cycle (without prescaler). If the TMR0 register is written, the increment is inhibited for the following two cycles (Figure 6-2 and Figure 6-3). The user can w ork 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 TMR0 will increment either on every rising or falling edge of pin RA4/T0CKI. The incrementing edge is determined by the T0 source

FIGURE 6-1: TMR0 BLOCK DIAGRAM

edge select bit, T0SE (OPTION<4>). Clearing bit T0SE selects the rising edge. Restrictions on the external clock input are discussed in detail in Section 6.2.

The prescaler is shared between the Timer0 Module and the Watchdog Timer. The prescaler assignment is controlled, in software, by control bit PSA (OPTION<3>). Clearing bit PSA will assign the prescaler to the Timer0 Module. The prescaler is not readable or writable. When the prescaler (Section 6.3) is assigned to the Timer0 Module, the prescale value (1:2, 1:4, ..., 1:256) is software selectable.

6.1 TMR0 Interrupt

The TMR0 interrupt is generated when the TMR0 register overﬂows from FFh to 00h. This overﬂow sets the T0IF bit (INTCON<2>). The interrupt can be masked by clearing enable bit T0IE (INTCON<5>). The T0IF bit must be cleared in software by the Timer0 Module interrupt service routine before re-enabling this interrupt. The TMR0 interrupt (Figure 6-4) cannot wake the processor from SLEEP since the timer is shut off during SLEEP.

T0CS

Programmable

Prescaler

PS2, PS1, PS0

PSA

PSout

Sync with

Internal

clocks

(2 cycle delay)

RA4/T0CKI

FOSC/4

T0SE

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

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

FIGURE 6-2: TMR0 TIMING: INTERNAL CLOCK/NO PRESCALER

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 PC+1 PC+2

MOVWF TMR0

T0+1 T0+2 NT0 NT0 NT0

MOVF TMR0,W

Write TMR0 executed

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

Read TMR0 reads NT0

PC+3

Read TMR0 reads NT0

PC+4

Read TMR0 reads NT0

Instruction

Fetch

TMR0

Instruction

Executed

Q1 Q2 Q3 Q4

PC-1

PSout

Data bus

TMR0 register

PC+5 PC+6

NT0+1 NT0+2

Read TMR0 reads NT0 + 1

Read TMR0 reads NT0 + 2

Set bit T0IF on Overﬂow

 1997 Microchip Technology Inc. DS30445C-page 25

PIC16C84

FIGURE 6-3: TMR0 TIMING: INTERNAL CLOCK/PRESCALE 1:2

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

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

MOVWF TMR0

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

T0+1

Write TMR0 executed

PC Instruction

Fetch

TMR0

Instruction Execute

Q1 Q2 Q3 Q4

PC-1

T0 NT0+1

FIGURE 6-4: TMR0 INTERRUPT TIMING

Q2Q1 Q3 Q4Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4

OSC1

(3)

CLKOUT

TMR0 timer

T0IF bit (INTCON<2>)

GIE bit (INTCON<7>)

UCTION FLOW

INSTR

Instruction fetched

FEh

Inst (PC)

FFh 00h 01h 02h

PC +1 PC +1 0004h

Inst (PC+1)

Read TMR0 reads NT0

Interrupt Latency

NT0

(2)

Read TMR0 reads NT0

Inst (0004h) Inst (0005h)

Read TMR0 reads NT0 + 1

0005h

Instruction executed

Inst (PC-1)

Inst (PC)

Inst (0004h)Dummy cycle Dummy cycle

Note 1: T0IF interrupt ﬂag is sampled here (every Q1).

2: Interrupt latency = 3.25Tcy, where Tcy = instruction cycle time. 3: CLKOUT is available only in RC oscillator mode.

4: The timer clock (after the synchronizer circuit) which increments the timer from FFh to 00h immediately sets the T0IF bit.

The TMR0 register will roll over 3 Tosc cycles later.

DS30445C-page 26  1997 Microchip Technology Inc.

PIC16C84

6.2 Using TMR0 with External Clock

When an external clock input is used for TMR0, it must meet certain requirements. The external clock requirement is due to internal phase clock (T synchronization. Also, there is a delay in the actual incrementing of the TMR0 register after synchronization.

6.2.1 EXTERNAL CLOCK SYNCHRONIZATION

When no prescaler is used, the external clock input is the same as the prescaler output. The synchronization of pin RA4/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 6-5). Therefore, it is necessary for T0CKI to be high for at least 2Tosc (plus a small RC delay) and low for at least 2Tosc (plus a small RC delay). Refer to the electrical speciﬁcation of the desired device.

When a prescaler is used, the external clock input is divided by an 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 4Tosc (plus a small RC delay) 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 AC Electrical Speciﬁcations of the desired device.

OSC)

6.2.2 TMR0 INCREMENT DELAY Since the prescaler output is synchronized with the

internal clocks, there is a small delay from the time the external clock edge occurs to the time the Timer0 Module is actually incremented. Figure 6-5 shows the delay from the external clock edge to the timer incrementing.

6.3 Prescaler

An 8-bit counter is available as a prescaler for the Timer0 Module, or as a postscaler for the Watchdog Timer (Figure 6-6). For simplicity, this counter is being referred to as “prescaler” throughout this data sheet. Note that there is only one prescaler available which is mutually exclusive betw een the Timer0 Module and the Watchdog Timer . Thus, a prescaler assignment for the Timer0 Module means that there is no prescaler for the Watchdog Timer , and vice-versa.

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

When assigned to the Timer0 Module, all instructions writing to the Timer0 Module (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 Watchdog Timer. The prescaler is not readable or writable.

FIGURE 6-5: TIMER0 TIMING WITH EXTERNAL CLOCK

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

Note 1:

2: 3:

Ext. Clock Input or

Prescaler Out (Note 2)

Ext. Clock/Prescaler

Output After Sampling

Increment TMR0 (Q4)

TMR0

Delay from clock input change to TMR0 increment is 3Tosc to 7Tosc. (Duration of Q = Tosc). Therefore, the error in measuring the interval between two edges on TMR0 input = ± 4Tosc max. External clock if no prescaler selected, Prescaler output otherwise. The arrows ↑ indicate where sampling occurs. A small clock pulse may be missed by sampling.

T0 T0 + 1 T0 + 2

(Note 3)

 1997 Microchip Technology Inc. DS30445C-page 27

PIC16C84

FIGURE 6-6: BLOCK DIAGRAM OF THE TMR0/WDT PRESCALER

CLKOUT (= Fosc/4)

RA4/T0CKI

Watchdog

Timer

WDT Enable bit

T0SE

Data Bus

U X

T0CS

PSA

8-bit Prescaler

8 - to - 1MUX

time-out

M U X

WDT

PSA

SYNC

Cycles

PS2:PS0

PSA

TMR0 register

Set bit T0IF

on overﬂow

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

DS30445C-page 28  1997 Microchip Technology Inc.

PIC16C84

6.3.1 SWITCHING PRESCALER ASSIGNMENT

The prescaler assignment is fully under software control (i.e., it can be changed “on the ﬂy” during program execution).

Note: To avoid an unintended de vice RESET, the

following instruction sequence (Example 6-1) must be executed when changing the prescaler assignment from

EXAMPLE 6-1: CHANGING PRESCALER

(TIMER0→WDT)

BCF STATUS, RP0 ;Bank 0 CLRF TMR0 ;Clear TMR0 ; and Prescaler BSF STATUS, RP0 ;Bank 1 CLRWDT ;Clears WDT MOVLW b'xxxx1xxx' ;Select new MOVWF OPTION ; prescale value BCF STATUS, RP0 ;Bank 0

Timer0 to the WDT. This sequence m ust be taken even if the WDT is disabled. To change prescaler from the WDT to the Timer0 module use the sequence shown in Example 6-2.

EXAMPLE 6-2: CHANGING PRESCALER

(WDT→TIMER0)

CLRWDT ;Clear WDT and ; prescaler BSF STATUS, RP0 ;Bank 1 MOVLW b'xxxx0xxx' ;Select TMR0, new ; prescale value ’ and clock source MOVWF OPTION ; BCF STATUS, RP0 ;Bank 0

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 all other resets

01h TMR0 Timer0 module’s register xxxx xxxx uuuu uuuu 0Bh INTCON GIE

81h OPTION 85h TRISA — — — TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 ---1 1111 ---1 1111

Legend: x = unknown, u = unchanged. - = unimplemented read as '0'. Shaded cells are not associated with Timer0.

RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

EEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 0000

 1997 Microchip Technology Inc. DS30445C-page 29

PIC16C84

NOTES:

DS30445C-page 30  1997 Microchip Technology Inc.

PIC16C84

7.0 DATA EEPROM MEMORY

The EEPROM data memory is readable and writable during normal operation (full V is not directly mapped in the register ﬁle space. Instead it is indirectly addressed through the Special Function Registers. There are four SFRs used to read and write this memory. These registers are:

• EECON1

• EECON2

• EEDATA

• EEADR

EEDATA holds the 8-bit data for read/write, and EEADR holds the address of the EEPROM location being accessed. PIC16C84 devices have 64 bytes of data EEPROM with an address range from 0h to 3Fh.

The EEPROM data memory allows byte read and write. A byte write automatically erases the location and writes the new data (erase before write). The EEPR OM data memory is rated for high erase/write cycles. The write time is controlled by an on-chip timer. The writetime will vary with voltage and temperature as well as from chip to chip. Please refer to AC speciﬁcations for exact limits.

DD range). This memory

When the device is code protected, the CPU may continue to read and write the data EEPROM memory . The device programmer can no longer access this memory.

7.1 EEADR

The EEADR register can address up to a maximum of 256 bytes of data EEPROM. Only the ﬁrst 64 bytes of data EEPROM are implemented.

The upper two bits are address decoded. This means that these two bits must always be '0' to ensure that the address is in the 64 byte memory space.

FIGURE 7-1: EECON1 REGISTER (ADDRESS 88h)

U U U R/W-0 R/W-x R/W-0 R/S-0 R/S-x

— — — EEIF WRERR WREN WR RD R = Readable bit

bit7 bit0

bit 7:5 Unimplemented: Read as '0' bit 4 EEIF: EEPROM Write Operation Interrupt Flag bit

1 = The write operation completed (must be cleared in software) 0 = The write operation is not complete or has not been started

bit 3 WRERR: EEPROM Error Flag bit

1 = A write operation is prematurely terminated

(any MCLR

0 = The write operation completed

bit 2 WREN: EEPROM Write Enable bit

1 = Allows write cycles 0 = Inhibits write to the data EEPROM

bit 1 WR: Write Control bit

1 = initiates a write cycle. (The bit is cleared by hardware once write is complete. The WR bit can only

be set (not cleared) in software.

0 = Write cycle to the data EEPROM is complete

bit 0 RD: Read Control bit

1 = Initiates an EEPROM read (read takes one cycle. RD is cleared in hardware. The RD bit can only

be set (not cleared) in software).

0 = Does not initiate an EEPROM read

reset or any WDT reset during normal operation)

W = Writable bit S = Settable bit U = Unimplemented bit,

- n = Value at POR reset

read as ‘0’

 1997 Microchip Technology Inc. DS30445C-page 31

PIC16C84

7.2 EECON1 and EECON2 Registers

EECON1 is the control register with ﬁve low order bits physically implemented. The upper-three bits are nonexistent and read as '0's.

Control bits RD and WR initiate read and write, respectively. These bits cannot be cleared, only set, in software. They are cleared in hardware at completion of the read or write operation. The inability to clear the WR bit in software prevents the accidental, premature termination of a write operation.

The WREN bit, when set, will allow a write operation. On power-up, the WREN bit is clear. The WRERR bit is set when a write operation is interrupted by a MCLR reset or a WDT time-out reset during normal operation. In these situations, following reset, the user can check the WRERR bit and rewrite the location. The data and address will be unchanged in the EEDATA and EEADR registers.

Interrupt ﬂag bit EEIF is set when write is complete. It must be cleared in software.

EECON2 is not a physical register. Reading EECON2 will read all '0's. The EECON2 register is used exclusively in the Data EEPROM write sequence.

7.3 Reading the EEPROM Data Memory

To read a data memory location, the user must write the address to the EEADR register and then set control bit RD (EECON1<0>). The data is av ailable , in the v ery next cycle, in the EEDATA register; therefore it can be read in the next instruction. EED AT A will hold this v alue until another read or until it is written to by the user (during a write operation).

EXAMPLE 7-1: DATA EEPROM READ

BCF STATUS, RP0 ; Bank 0 MOVLW CONFIG_ADDR ; MOVWF EEADR ; Address to read BSF STATUS, RP0 ; Bank 1 BSF EECON1, RD ; EE Read BCF STATUS, RP0 ; Bank 0 MOVF EEDATA, W ; W = EEDATA

7.4 Writing to the EEPROM Data Memory

To write an EEPROM data location, the user must ﬁrst write the address to the EEADR register and the data to the EEDATA register. Then the user must follow a speciﬁc sequence to initiate the write for each byte.

EXAMPLE 7-1: DATA EEPROM WRITE

BSF STATUS, RP0 ; Bank 1 BCF INTCON, GIE ; Disable INTs. BSF EECON1, WREN ; Enable Write MOVLW 55h ; MOVWF EECON2 ; Write 55h MOVLW AAh ; MOVWF EECON2 ; Write AAh BSF EECON1,WR ; Set WR bit ; begin write

Required

Sequence

BSF INTCON, GIE ; Enable INTs.

The write will not initiate if the above sequence is not exactly followed (write 55h to EECON2, write AAh to EECON2, then set WR bit) for each byte. We strongly recommend that interrupts be disabled during this code segment.

Additionally, the WREN bit in EECON1 must be set to enable write. This mechanism prevents accidental writes to data EEPROM due to errant (unexpected) code execution (i.e., lost programs). The user should keep the WREN bit clear at all times, except when updating EEPROM. The WREN bit is not cleared by hardware

After a write sequence has been initiated, clearing the WREN bit will not affect this write cycle. The WR bit will be inhibited from being set unless the WREN bit is set.

At the completion of the write cycle, the WR bit is cleared in hardware and the EE Write Complete Interrupt Flag bit (EEIF) is set. The user can either enable this interrupt or poll this bit. EEIF must be cleared by software.

Note: The data EEPROM memory E/W cycle

time may occasionally exceed the 10 ms speciﬁcation (typical). To ensure that the write cycle is complete, use the EE interrupt or poll the WR bit (EECON1<1>). Both these events signify the completion of the write cycle.

DS30445C-page 32  1997 Microchip Technology Inc.

PIC16C84

7.5 Write Verify

Depending on the application, good programming practice may dictate that the value written to the Data EEPROM should be veriﬁed (Example 7-1) to the desired value to be written. This should be used in applications where an EEPROM bit will be stressed near the speciﬁcation limit. The Total Endurance disk will help determine your comfort level.

Generally the EEPROM write failure will be a bit which was written as a '1', but reads back as a '0' (due to leakage off the bit).

EXAMPLE 7-1: WRITE VERIFY

BCF STATUS, RP0 ; Bank 0 : ; Any code can go here : ; MOVF EEDATA, W ; Must be in Bank 0 BSF STATUS, RP0 ; Bank 1 READ BSF EECON1, RD ; YES, Read the ; value written BCF STATUS, RP0 ; Bank 0 ; ; Is the value written (in W reg) and ; read (in EEDATA) the same? ; SUBWF EEDATA, W ; BTFSS STATUS, Z ; Is difference 0? GOTO WRITE_ERR ; NO, Write error : ; YES, Good write : ; Continue program

7.6 Protection Against Spurious Writes

There are conditions when the device may not want to write to the data EEPROM memory. To protect against spurious EEPROM writes, various mechanisms have been built in. On power-up, WREN is cleared. Also, the Pow er-up Timer (72 ms duration) prevents EEPROM write.

The write initiate sequence and the WREN bit together help prevent an accidental write during brown-out, power glitch, or software malfunction.

7.7 Data EEPROM Operation during Code Protect

When the device is code protected, the CPU is able to read and write unscrambled data to the Data EEPROM.

For ROM devices, there are two code protection bits (Section 8.1). One for the ROM program memory and one for the Data EEPROM memory.

7.8 Power Consumption Considerations

Note: It is recommended that the EEADR<7:6>

bits be cleared. When either of these bits is set, the maximum I higher than when both are cleared. The speciﬁcation is 400 µA. With EEADR<7:6> cleared, the maximum is approximately 150 µA.

DD for the device is

TABLE 7-1 REGISTERS/BITS ASSOCIATED WITH DATA EEPROM

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

08h EEDA TA EEPROM data register xxxx xxxx uuuu uuuu 09h EEADR EEPROM address register xxxx xxxx uuuu uuuu 88h EECON1 89h EECON2 EEPROM control register 2 ---- ---- ---- ----

Legend: x = unknown, u = unchanged, - = unimplemented read as '0', q = value depends upon condition. Shaded cells are not

used by Data EEPROM.

— — — EEIF WRERR WREN WR RD ---0 x000 ---0 q000

Value on

Power-on

Reset

Value on all other resets

 1997 Microchip Technology Inc. DS30445C-page 33

PIC16C84

NOTES:

DS30445C-page 34  1997 Microchip Technology Inc.

PIC16C84

8.0 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 PIC16C84 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:

• OSC selection

• Reset

- Power-on Reset (POR)

- Power-up Timer (PWRT)

- Oscillator Start-up Timer (OST)

• Interrupts

• Watchdog Timer (WDT)

• SLEEP

• Code protection

• ID locations

• In-circuit serial programming

The PIC16C84 has a Watchdog Timer which can be shut off only through conﬁguration bits. It runs off its own RC oscillator for added reliability. There are two timers that offer necessary delays on power-up. One is the Oscillator Start-up Timer (OST), intended to keep

the chip in reset until the crystal oscillator is stable. The other is the Pow er-up Timer (PWRT), which provides a ﬁxed delay of 72 ms (nominal) on power-up only. This design keeps the device in reset while the pow er supply stabilizes. With these two timers on-chip, most applications need no external reset circuitry.

SLEEP mode offers a very low current power-down mode. The user can wake-up from SLEEP through external reset, Watchdog Timer time-out or through an interrupt. Several oscillator options are provided to allow the part to ﬁt the application. The RC oscillator option saves system cost while the LP crystal option saves power. A set of conﬁguration bits are used to select the various options.

8.1 Conﬁguration Bits

The conﬁguration bits can be programmed (read as '0') or left unprogrammed (read as '1') to select various device conﬁgurations. These bits are mapped in program memory location 2007h.

Address 2007h is beyond the user program memory space and it belongs to the special test/conﬁguration memory space (2000h - 3FFFh). This space can only be accessed during programming.

To ﬁnd out how to program the PIC16C84, refer to

PIC16C84 EEPROM Memory Programming Speciﬁcation

(DS30189).

FIGURE 8-1: CONFIGURATION WORD

U-1 U-1 U-1 U-1 U-1 U-1 U-1 U-1 U-1 R/P-u R/P-u R/P-u R/P-u R/P-u

— — — — — — — — — CP PWRTE WDTE FOSC1 FOSC0

bit13 bit0

R = Readable bit P = Programmable bit U = Unimplemented bit,

read as ‘1’

- n = Value at POR reset u = unchanged

bit 13:5 Unimplemented: Read as '1' bit 4 CP: Code Protection bit

1 = Code protection off 0 = All memory is code protected

bit 3 PWRTE: Power-up Timer Enable bit

1 = Power-up timer is enabled 0 = Power-up timer is disabled

bit 2 WDTE: Watchdog Timer Enable bit

1 = WDT enabled 0 = WDT disabled

bit 1:0 FOSC1:FOSC0: Oscillator Selection bits

11 =RC oscillator 10 = HS oscillator 01 = XT oscillator 00 = LP oscillator

 1997 Microchip Technology Inc. DS30445C-page 35

PIC16C84

8.2 Oscillator Conﬁgurations

8.2.1 OSCILLATOR TYPES The PIC16C84 can be operated in four different

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

• LP Low Power Crystal

• XT Crystal/Resonator

• HS High Speed Crystal/Resonator

• RC Resistor/Capacitor

8.2.2 CRYSTAL OSCILLATOR / CERAMIC RESONATORS

In XT, LP or HS modes a crystal or ceramic resonator is connected to the OSC1/CLKIN and OSC2/CLKOUT pins to establish oscillation (Figure 8-2).

FIGURE 8-2: CRYSTAL/CERAMIC

RESONATOR OPERATION (HS, XT OR LP OSC CONFIGURATION)

(1)

XTAL

(2)

OSC1

OSC2

(3)

internal logic

SLEEP

PIC16CXX

Note1: See Table 8-1 and Table 8-2 for recom-

mended 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.

The PIC16C84 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 , LP or HS modes , the device can have an external clock source to drive the OSC1/ CLKIN pin (Figure 8-3).

FIGURE 8-3: EXTERNAL CLOCK INPUT

OPERATION (HS, XT OR LP OSC CONFIGURATION)

Clock from ext. system

Open

OSC1

PIC16CXX

OSC2

TABLE 8-1 CAPACITOR SELECTION

FOR CERAMIC RESONATORS

Ranges Tested:

Mode Freq OSC1/C1 OSC2/C2

XT 455 kHz

2.0 MHz

4.0 MHz

HS 8.0 MHz

10.0 MHz

Note: Recommended values of C1 and C2 are identical to

the ranges tested table. Higher capacitance increases the stability of the

oscillator but also increases the start-up time. These values are for design guidance only. Since each resonator has its own characteristics, the user should consult the resonator manufacturer for the appropriate values of external components.

47 - 100 pF

15 - 33 pF 15 - 33 pF

47 - 100 pF

15 - 33 pF 15 - 33 pF

Resonators Tested:

455 kHz Panasonic EFO-A455K04B ± 0.3%

2.0 MHz Murata Erie CSA2.00MG ± 0.5%

4.0 MHz Murata Erie CSA4.00MG ± 0.5%

8.0 MHz Murata Erie CSA8.00MT ± 0.5%

10.0 MHz Murata Erie CSA10.00MTZ ± 0.5%

None of the resonators had built-in capacitors.

TABLE 8-2 CAPACITOR SELECTION

FOR CRYSTAL OSCILLATOR

Mode Freq OSC1/C1 OSC2/C2

LP 32 kHz

200 kHz

XT 100 kHz

2 MHz 4 MHz

HS 4 MHz

10 MHz

Note: Higher capacitance increases the stability of

oscillator but also increases the start-up time. These values are for design guidance only. Rs may be required in HS mode as well as XT mode to avoid overdriving crystals with low drive level speciﬁcation. Since each crystal has its own characteristics, the user should consult the crystal manufacturer for appropriate values of external components.

For VDD > 4.5V, C1 = C2 ≈ 30 pF is recommended.

Crystals Tested:

32.768 kHz Epson C-001R32.768K-A ± 20 PPM 100 kHz Epson C-2 100.00 KC-P ± 20 PPM 200 kHz STD XTL 200.000 KHz ± 20 PPM

1.0 MHz ECS ECS-10-13-2 ± 50 PPM

2.0 MHz ECS ECS-20-S-2 ± 50 PPM

4.0 MHz ECS ECS-40-S-4 ± 50 PPM

10.0 MHz ECS ECS-100-S-4 ± 50 PPM

68 - 100 pF

15 - 33 pF

100 - 150 pF

15 - 33 pF 15 - 33 pF

68 - 100 pF

15 - 33 pF

100 - 150 pF

15 - 33 pF 15 - 33 pF

DS30445C-page 36  1997 Microchip Technology Inc.

PIC16C84

8.2.3 EXTERNAL CRYSTAL OSCILLATOR CIRCUIT

Either a prepackaged oscillator can be used or a simple oscillator circuit with TTL gates can be built. 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 are available; one with series resonance, and one with parallel resonance.

Figure 8-4 shows a parallel resonant oscillator circuit. The circuit is designed to use the fundamental frequency of the crystal. The 74AS04 in verter performs the 180-degree phase shift that a parallel oscillator requires. The 4.7 kΩ resistor provides negative feedback for stability. The 10 kΩ potentiometer biases the 74AS04 in the linear region. This could be used for external oscillator designs.

FIGURE 8-4: EXTERNAL PARALLEL

RESONANT CRYSTAL OSCILLATOR CIRCUIT

+5V

10k

4.7k

74AS04

10k

XTAL

10k

20 pF

Figure 8-5 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. The 330 kΩ resistors provide the negative feedback to bias the inverters in their linear region.

74AS04

To Other Devices

PIC16CXX

CLKIN

FIGURE 8-5: EXTERNAL SERIES

RESONANT CRYSTAL OSCILLATOR CIRCUIT

To Other

74AS04

Devices

PIC16CXX

CLKIN

330 kΩ

74AS04

330 kΩ

74AS04

0.1 µF XTAL

8.2.4 RC OSCILLATOR For timing insensitive applications the RC de vice option

offers additional cost savings. The RC oscillator frequency is a function of the supply voltage, the resistor (Rext) values, 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 also affects the oscillation frequency, especially for low Cext values. The user needs to take into account variation due to tolerance of the external R and C components. Figure 8-6 shows how an R/C combination is connected to the PIC16C84. 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 little or no external capacitance, the oscillation frequency can vary dramatically due to changes in external capacitances, such as PCB trace capacitance or package lead frame capacitance.

See the electrical speciﬁcation section for 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 has a greater affect on RC frequency).

See the electrical speciﬁcation section for variation of oscillator frequency due to V

DD for given Rext/Cext

values as well as frequency variation due to operating temperature.

The oscillator frequency, divided by 4, is available on the OSC2/CLKOUT pin, and can be used for test purposes or to synchronize other logic (see Figure 3-2 for waveform).

FIGURE 8-6: RC OSCILLATOR MODE

VDD

Rext

OSC1

Cext

VSS

Fosc/4

Recommended values: 3 kΩ ≤ Rext ≤ 100 kΩ

OSC2/CLKOUT

Cext > 20pF

Note: When the device oscillator is in RC mode,

do not drive the OSC1 pin with an external clock or you may damage the device.

Internal

clock

PIC16CXX

 1997 Microchip Technology Inc. DS30445C-page 37

PIC16C84

8.3 Reset

Some registers are not affected in any reset condition; their status is unknown on a POR reset and unchanged

The PIC16C84 differentiates between various kinds of reset:

• Power-on Reset (POR)

• MCLR

reset during normal operation reset during SLEEP

• WDT Reset (during normal operation)

• WDT Wake-up (during SLEEP) Figure 8-7 shows a simpliﬁed block diagram of the on-

chip reset circuit. The electrical speciﬁcations state the pulse width requirements for the MCLR

pin.

in any other reset. Most other registers are reset to a “reset state” on POR, MCLR normal operation and on MCLR They are not affected by a WDT reset during SLEEP, since this reset is viewed as the resumption of normal operation.

Table 8-3 gives a description of reset conditions for the program counter (PC) and the STATUS register. Table 8-4 gives a full description of reset states for all registers.

The T

O and PD bits are set or cleared differently in different reset situations (Section 8.7). These bits are used in software to determine the nature of the reset.

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

External

Reset

MCLR

SLEEP

WDT

Time_Out Reset

Power_on_Reset

OST

10-bit Ripple counter

PWRT

10-bit Ripple counter

VDD

OSC1/ CLKIN

Module

OST/PWRT

On-chip

RC OSC

WDT

DD rise

detect

(1)

or WDT reset during

reset during SLEEP.

Chip_Reset

Enable PWRT

Note 1: This is a separate oscillator from the

RC oscillator of the CLKIN pin.

DS30445C-page 38  1997 Microchip Technology Inc.

Enable OST

See Table 8-5

PIC16C84

TABLE 8-3 RESET CONDITION FOR PROGRAM COUNTER AND THE STATUS REGISTER

Condition

Program Counter STATUS Register

Power-on Reset 000h 0001 1xxx

Reset during normal operation 000h 000u uuuu

MCLR

Reset during SLEEP 000h 0001 0uuu

MCLR WDT Reset (during normal operation) 000h 0000 1uuu WDT Wake-up PC + 1 uuu0 0uuu

Interrupt wake-up from SLEEP PC + 1

(1)

uuu1 0uuu

Legend: u = unchanged, x = unknown. Note 1: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector

(0004h).

TABLE 8-4 RESET CONDITIONS FOR ALL REGISTERS

Reset during:

MCLR – normal operation

– SLEEP WDT Reset during normal operation

W — xxxx xxxx uuuu uuuu uuuu uuuu INDF 00h ---- ---- ---- ---- ---- ---TMR0 01h xxxx xxxx uuuu uuuu uuuu uuuu PCL 02h 0000h 0000h PC + 1 STATUS 03h 0001 1xxx 000q quuu

(3)

FSR 04h xxxx xxxx uuuu uuuu uuuu uuuu PORTA 05h ---x xxxx ---u uuuu ---u uuuu PORTB 06h xxxx xxxx uuuu uuuu uuuu uuuu EEDATA 08h xxxx xxxx uuuu uuuu uuuu uuuu EEADR 09h xxxx xxxx uuuu uuuu uuuu uuuu PCLATH 0Ah ---0 0000 ---0 0000 ---u uuuu INTCON 0Bh 0000 000x 0000 000u uuuu uuuu INDF 80h ---- ---- ---- ---- ---- ---OPTION_REG 81h 1111 1111 1111 1111 uuuu uuuu PCL 82h 0000h 0000h PC + 1 STATUS 83h 0001 1xxx 000q quuu

(3)

FSR 84h xxxx xxxx uuuu uuuu uuuu uuuu TRISA 85h ---1 1111 ---1 1111 ---u uuuu TRISB 86h 1111 1111 1111 1111 uuuu uuuu EECON1 88h ---0 x000 ---0 q000 ---0 uuuu EECON2 89h ---- ---- ---- ---- ---- ---PCLATH 8Ah ---0 0000 ---0 0000 ---u uuuu INTCON 8Bh 0000 000x 0000 000u uuuu uuuu Legend: u = unchanged, x = unknown, - = unimplemented bit read as '0',

q = value depends on condition.

Note 1: One or more bits in INTCON will be affected (to cause wake-up).

2: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector

(0004h).

3: Table 8-3 lists the reset value for each speciﬁc condition.

Wake-up from SLEEP: – through interrupt – through WDT time-out

(2)

uuuq quuu

(3)

(1)

(3)

(1)

 1997 Microchip Technology Inc. DS30445C-page 39

PIC16C84

8.4 Power-on Reset (POR)

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

DD rise is detected (in the range of 1.2V - 1.7V). To

take advantage of the POR, just tie the MCLR directly (or through a resistor) to V

DD. This will eliminate

external RC components usually needed to create Power-on Reset. A minimum rise time for V

DD must be

met for this to operate properly. See Electrical Speciﬁcations for details.

When the device starts normal operation (exits the reset condition), device operating parameters (v oltage , frequency, temperature, ...) 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.

For additional information, refer to Application Note AN607,

Power-up Trouble Shooting

The POR circuit does not produce an internal reset when V

DD declines.

8.5 Power-up Timer (PWRT)

The Power-up Timer (PWRT) provides a ﬁxed 72 ms nominal time-out (T Figure 8-10, Figure 8-11 and Figure 8-12). The Powerup Timer operates on an internal RC oscillator. The chip is kept in reset as long as the PWRT is active . The PWRT delay allows the V level (Possible exception shown in Figure 8-12).

A conﬁguration bit, PWRTE, can enable/disable the PWRT (Figure 8-1).

The power-up time delay T chip due to V

DD, temperature, and process variation.

See DC parameters for details.

PWRT) from POR (Figure 8-9,

DD to rise to an acceptable

PWRT will vary from chip to

FIGURE 8-8: EXTERNAL POWER-ON

RESET CIRCUIT (FOR SLOW VDD POWER-UP)

VDD

Note 1: External Pow er-on Reset circuit is required

2: R < 40 kΩ is recommended to make sure

3: R1 = 100Ω to 1 kΩ will limit any current

only if V

DD power-up rate is too slow. The

MCLR

PIC16CXX

diode D helps discharge the capacitor quickly when V

DD powers down.

that voltage drop across R does not exceed

0.2V (max leakage current spec on MCLR pin is 5 µA). A larger v oltage drop will degrade V

ﬂowing into MCLR

IH level on the MCLR pin.

from external capacitor C in the event of an MCLR breakdown due to ESD or EOS.

8.6 Oscillator Start-up Timer (OST)

The Oscillator Start-up Timer (OST) provides a 1024 oscillator cycle delay (from OSC1 input) after the PWRT delay ends (Figure 8-9, Figure 8-10, Figure 811 and Figure 8-12). This ensures the crystal oscillator or resonator has started and stabilized.

The OST time-out (T HS modes and only on Power-on Reset or wake-up from SLEEP.

When V T V

DD rises very slowly, it is possible that the

PWRT time-out and TOST time-out will expire before

DD has reached its ﬁnal value. In this case (Figure 8-

12), an external power-on reset circuit may be necessary (Figure 8-8).

DS30445C-page 40  1997 Microchip Technology Inc.

OST) is invoked only f or XT, LP and

PIC16C84

FIGURE 8-9: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1

VDD

MCLR

INTERNAL POR

TPWRT

PWR

T TIME-OUT

OST TIME-OUT

INTERNAL RESET

FIGURE 8-10: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2

VDD

TOST

MCLR

INTERNAL POR

PWR

T TIME-OUT

OST TIME-OUT

INTERNAL RESET

TPWRT

TOST

 1997 Microchip Technology Inc. DS30445C-page 41

PIC16C84

FIGURE 8-11: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD): FAST VDD RISE TIME

VDD

MCLR

INTERNAL POR

TPWRT

PWRT TIME-OUT

OST TIME-OUT

INTERNAL RESET

FIGURE 8-12: TIME-OUT SEQUENCE ON POWER-UP (MCLR

VDD

MCLR

INTERNAL POR

TPWRT

PWRT TIME-OUT

OST TIME-OUT

INTERNAL RESET

TOST

TIED TO VDD): SLO W VDD RISE TIME

TOST

When VDD rises very slowly, it is possible that the TPWRT time-out and TOST time-out will expire before VDD has reached its ﬁnal value. In this example, the chip will reset properly if, and only if, V1 ≥ VDD min.

DS30445C-page 42  1997 Microchip Technology Inc.

PIC16C84

8.7 Time-out Sequence and Power Down Status Bits (TO/PD)

On power-up (Figure 8-9, Figure 8-10, Figure 8-11 and Figure 8-12) the time-out sequence is as follows: First PWRT time-out is invoked after a POR has expired. Then the OST is activated. The total time-out will vary based on oscillator conﬁguration and PWRTE conﬁguration bit status. For example, in RC mode with the PWRT disabled, there will be no time-out at all.

TABLE 8-5 TIME-OUT IN VARIOUS

SITUATIONS

Oscillator

Conﬁguration

XT, HS, LP 72 ms +

RC 72 ms — —

Since the time-outs occur from the POR reset pulse, if MCLR

is kept low long enough, the time-outs will expire. Then bringing MCLR immediately (Figure 8-9). This is useful for testing purposes or to synchronize more than one PIC16CXX device when operating in parallel.

Table 8-6 sho ws the signiﬁcance of the T T ab le 8-3 lists the reset conditions for some special registers, while Table 8-4 lists the reset conditions for all the registers.

Power-up Wake-up

PWRT

Enabled

1024TOSC

PWRT

Disabled

1024TOSC 1024TOSC

high, execution will begin

from

SLEEP

O and PD bits.

TABLE 8-6 STATUS BITS AND THEIR

SIGNIFICANCE

TO PD Condition

1 1 Power-on Reset 0 x Illegal, T x 0 Illegal, PD is set on POR 0 1 WDT Reset (during normal operation) 0 0 WDT Wake-up 1 1 MCLR 1 0 MCLR

wake-up from SLEEP

O is set on POR

Reset during normal operation Reset during SLEEP or interrupt

8.8 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 PIC16C84 devices when a brown-out occurs, external brown-out protection circuits may be built, as shown in Figure 8-13 and Figure 8-14.

FIGURE 8-13: BROWN-OUT PROTECTION

CIRCUIT 1

VDD

33k

10k

This circuit will activate reset when VDD goes below (Vz + 0.7V) where Vz = Zener voltage.

40k

MCLR

PIC16CXX

FIGURE 8-14: BROWN-OUT PROTECTION

CIRCUIT 2

VDD

MCLR

This brown-out circuit is less expensive, although less accurate. Transistor Q1 turns off when VDD is below a certain level such that:

40k

PIC16CXX

VDD •

 1997 Microchip Technology Inc. DS30445C-page 43

R1 + R2

= 0.7V

PIC16C84

8.9 Interrupts

The PIC16C84 has 4 sources of interrupt:

• External interrupt RB0/INT pin

• TMR0 overﬂow interrupt

• PORTB change interrupts (pins RB7:RB4)

• EEPROM write complete interrupt The interrupt control register (INTCON) records

individual interrupt requests in ﬂag bits. It also contains the individual and global interrupt enable bits.

The global interrupt enable bit, GIE (INTCON<7>) enables (if set) all un-masked interrupts or disables (if cleared) all interrupts. Individual interrupts can be disabled through their corresponding enable bits in INTCON register. Bit GIE is cleared on reset.

The “return from interrupt” instruction, RETFIE, exits interrupt routine as well as sets the GIE bit, which reenable interrupts.

The RB0/INT pin interrupt, the RB port change interrupt and the TMR0 overﬂow interrupt ﬂags are contained in the INTCON register.

When an interrupt is responded to; the GIE bit is cleared to disable any further interrupt, the return address is pushed onto the stack and the PC is loaded with 0004h. For external interrupt events, such as the RB0/INT pin or PORTB change interrupt, the interrupt latency will be three to four instruction cycles. The exact latency depends when the interrupt event occurs (Figure 8-16). The latency is the same for both one and two cycle instructions. Once in the interrupt service routine the source(s) of the interrupt can be determined by polling the interrupt ﬂag bits. The interrupt ﬂag bit(s) must be cleared in software before re-enabling interrupts to avoid inﬁnite interrupt requests.

Note 1: Individual interrupt ﬂag bits are set

regardless of the status of their corresponding mask bit or the GIE bit.

Note 2: If an interrupt occurs while the Global

Interrupt Enable (GIE) bit is being cleared, the GIE bit may unintentionally be re-enabled by the user’s Interrupt Service Routine (the RETFIE instruction). The events that would cause this to occur are:

1. An instruction clears the GIE bit while an interrupt is acknowledged

2. The program branches to the Interrupt vector and executes the Interrupt Service Routine.

3. The Interrupt Service Routine completes with the execution of the RETFIE instruction. This causes the GIE bit to be set (enables interrupts), and the program returns to the instruction after the one which was meant to disable interrupts.

The method to ensure that interrupts are globally disabled is:

1. Ensure that the GIE bit is cleared by the instruction, as shown in the following code:

LOOP BCF INTCON,GIE ;Disable All ; Interrupts BTFSC INTCON,GIE ;All Interrupts ; Disabled? GOTO LOOP ;NO, try again ; Yes, continue ; with program ; flow

DS30445C-page 44  1997 Microchip Technology Inc.

FIGURE 8-15: INTERRUPT LOGIC

PIC16C84

T0IF T0IE

INTF INTE

RBIF RBIE

EEIF EEIE

GIE

FIGURE 8-16: INT PIN INTERRUPT TIMING

Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4

OSC1

CLKOUT

INT pin

INTF ﬂag (INTCON<1>)

GIE bit (INTCON<7>)

INSTR

Instruction fetched

UCTION FLOW

Inst (PC)

PC+1

Inst (PC+1)

Interrupt Latency

PC+1

—

Wake-up (If in SLEEP mode)

Interrupt to CPU

0004h

Inst (0004h)

0005h

Inst (0005h)

Instruction executed

Note

1: INTF ﬂag is sampled here (every Q1). 2: Interrupt latency = 3-4Tcy where Tcy = instruction cycle time.

Latency is the same whether Inst (PC) is a single cycle or a 2-cycle instruction. 3: CLKOUT is available only in RC oscillator mode. 4: For minimum width of INT pulse, refer to AC specs. 5: INTF is enabled to be set anytime during the Q4-Q1 cycles.

Inst (PC-1)

Inst (PC)

Dummy Cycle

Inst (0004h)

 1997 Microchip Technology Inc. DS30445C-page 45

PIC16C84

8.9.1 INT INTERRUPT External interrupt on RB0/INT pin is edge triggered:

either rising if INTEDG bit (OPTION_REG<6>) is set, or falling, if INTEDG bit is clear. When a valid edge appears on the RB0/INT pin, the INTF bit (INTCON<1>) is set. This interrupt can be disabled by clearing control bit INTE (INTCON<4>). Flag bit INTF must be cleared in software via the interrupt service routine before re-enabling this interrupt. The INT interrupt can wake the processor from SLEEP (Section 8.12) only if the INTE bit was set prior to going into SLEEP. The status of the GIE bit decides whether the processor branches to the interrupt vector following wake-up.

8.9.2 TMR0 INTERRUPT An overﬂow (FFh → 00h) in TMR0 will set ﬂag bit T0IF

(INTCON<2>). The interrupt can be enabled/disabled by setting/clearing enable bit T0IE (INTCON<5>) (Section 6.0).

8.9.3 PORT RB INTERRUPT An input change on PORTB<7:4> sets ﬂag bit RBIF

(INTCON<0>). The interrupt can be enabled/disabled by setting/clearing enable bit RBIE (INTCON<3>) (Section 5.2).

8.10 Context Saving During Interrupts

During an interrupt, only the return PC value is saved on the stack. Typically, users wish to save key register values during an interrupt (e.g., W register and STA TUS register). This is implemented in software.

Example 8-1 stores and restores the STATUS and W register’s v alues. The User deﬁned registers, W_TEMP and STATUS_TEMP are the temporary storage locations for the W and STATUS registers values.

Example 8-1 does the following: a) Stores the W register.

b) Stores the STATUS register in STATUS_TEMP. c) Executes the Interrupt Service Routine code. d) Restores the STATUS (and bank select bit)

e) Restores the W register.

Note 1: If a change on an I/O pin should occur

when a read operation of PORTB is being executed (start of the Q2 cycle), the RBIF interrupt ﬂag bit may not get set.

EXAMPLE 8-1: SAVING STATUS AND W REGISTERS IN RAM

PUSH MOVWF W_TEMP ; Copy W to TEMP register, SWAPF STATUS, W ; Swap status to be saved into W MOVWF STATUS_TEMP ; Save status to STATUS_TEMP register ISR : : : ; Interrupt Service Routine : ; should configure Bank as required : ; POP SWAPF STATUS_TEMP, W ; Swap nibbles in STATUS_TEMP register ; and place result into W MOVWF STATUS ; Move W into STATUS register ; (sets bank to original state) SWAPF W_TEMP, F ; Swap nibbles in W_TEMP and place result in W_TEMP SWAPF W_TEMP, W ; Swap nibbles in W_TEMP and place result into W

DS30445C-page 46  1997 Microchip Technology Inc.

PIC16C84

8.11 Watchdog Timer (WDT)

part (see DC specs). If longer time-out periods are desired, a prescaler with a division ratio of up to 1:128

The Watchdog Timer is a free running on-chip RC oscillator which does not require any external components. This RC oscillator is separate from the RC oscillator of the OSC1/CLKIN pin. That means that the WDT will run even if the clock on the OSC1/CLKIN and OSC2/CLKOUT pins of the device has been stopped, for example, by execution of a SLEEP instruction. During normal operation a WDT time-out generates a device RESET. If the device is in SLEEP mode, a WDT Wake-up causes the device to wake-up and continue with normal operation. The WDT can be permanently disabled by programming conﬁguration bit WDTE as a '0' (Section 8.1).

8.11.1 WDT PERIOD The WDT has a nominal time-out period of 18 ms, (with

can be assigned to the WDT under software control by writing to the OPTION_REG register. Thus, time-out periods up to 2.3 seconds can be realized.

The CLRWDT and SLEEP instructions clear the WDT and the postscaler (if assigned to the WDT) and prevent it from timing out and generating a device RESET condition.

The T a WDT time-out.

8.11.2 WDT PROGRAMMING CONSIDERATIONS It should also be taken into account that under worst

case conditions (V WDT prescaler) it may take several seconds before a

WDT time-out occurs. no prescaler). The time-out periods vary with temperature, V

DD and process variations from part to

FIGURE 8-17: WATCHDOG TIMER BLOCK DIAGRAM

From TMR0 Clock Source (Figure 6-6)

O bit in the STATUS register will be cleared upon

DD = Min., Temperature = Max., max.

WDT Timer

WDT

Enable Bit

•

U X

PSA

Postscaler

8 - to -1 MUX

MUX

WDT

Time-out

PS2:PS0

•

To TMR0 (Figure 6-6)

PSA

Note: PSA and PS2:PS0 are bits in the OPTION_REG register.

TABLE 8-7 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

2007h Conﬁg. bits

81h

Legend: x = unknown. Shaded cells are not used by the WDT.

OPTION_ REG

— — — CP PWRTE WDTE FOSC1 FOSC0

RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0

Value on

Power-on

Reset

1111 1111 1111 1111

Value on all

other resets

 1997 Microchip Technology Inc. DS30445C-page 47

PIC16C84

8.12 Power-down Mode (SLEEP)

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

8.12.1 SLEEP The Power-down mode is entered by executing the

SLEEP instruction. If enabled, the Watchdog Timer is cleared (but keeps

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

For the lowest current consumption in SLEEP mode, place all I/O pins at either at V external circuitry drawing current from the I/O pins, and disable external clocks. I/O pins that are hi-impedance inputs should be pulled high or low externally to avoid switching currents caused by ﬂoating inputs. The T0CKI input should also be at V contribution from on-chip pull-ups on PORTB should be considered.

The MCLR It should be noted that a RESET generated by a WDT

time-out does not drive the MCLR

bit (ST ATUS<3>) is cleared, the T O bit

DD or VSS, with no

DD or VSS. The

pin must be at a logic high level (VIHMC).

pin low.

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

the following events:

1. External reset input on MCLR

pin.

2. WDT Wake-up (if WDT was enabled).

3. Interrupt from RB0/INT pin, RB por t change, or data EEPROM write complete.

Peripherals cannot generate interrupts during SLEEP, since no on-chip Q clocks are present.

The ﬁrst event (MCLR

reset) will cause a device reset. The two latter events are considered a continuation of program ex ecution. The T determine the cause of a device reset. The PD

O and PD bits can be used to

bit, which is set on power-up, is cleared when SLEEP is invoked. The T

O bit is cleared if a WDT time-out

occurred (and caused wake-up). While the SLEEP instruction is being executed, the ne xt

instruction (PC + 1) is pre-fetched. For the device to wake-up through an interrupt event, the corresponding interrupt enable bit must be set (enabled). Wake-up occurs regardless of the state of the GIE bit. If the GIE bit is clear (disabled), the device continues e xecution at the instruction after the SLEEP instruction. If the GIE bit is set (enabled), the device executes the instruction after the SLEEP instruction and then branches to the interrupt address (0004h). In cases where the execution of the instruction following SLEEP is not desirable, the user should have a NOP after the SLEEP instruction.

FIGURE 8-18: WAKE-UP FROM SLEEP THROUGH INTERRUPT

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

OSC1

OST(2)

CLKOUT(4)

INT pin

INTF ﬂag (INTCON<1>)

GIE bit (INTCON<7>)

UCTION FLOW

INSTR

Instruction fetched

Instruction executed

Note 1: XT, HS or LP oscillator mode assumed.

2: T 3: GIE = '1' assumed. In this case after wake- up, the processor jumps to the interrupt routine. If GIE = '0', execution will continue in-line. 4: CLKOUT is not available in these osc modes, but shown here for timing reference.

PC PC+1 PC+2

Inst(PC) = SLEEP

Inst(PC - 1)

OST = 1024TOSC (drawing not to scale) This delay will not be there for RC osc mode.

Inst(PC + 1)

SLEEP

Processor in

SLEEP

Interrupt Latency

(Note 2)

PC+2

Inst(PC + 2)

Inst(PC + 1)

Dummy cycle

PC + 2 0004h 0005h

Inst(0004h)

Dummy cycle

Inst(0005h)

Inst(0004h)

DS30445C-page 48  1997 Microchip Technology Inc.

PIC16C84

8.12.3 WAKE-UP USING INTERRUPTS When global interrupts are disabled (GIE cleared) and

any interrupt source has both its interrupt enable bit and interrupt ﬂag bit set, one of the following will occur:

• If the interrupt occurs before the execution of a SLEEP instruction, the SLEEP instruction will complete as a NOP. Therefore, the WDT and WDT postscaler will not be cleared, the T be set and PD

bits will not be cleared.

O bit will not

• If the interrupt occurs during or after the execution of a SLEEP instruction, the device will immediately wake up from sleep . The SLEEP instruction will be completely executed before the wake-up. Therefore, the WDT and WDT postscaler will be cleared, the T and the PD

bit will be cleared.

O bit will be set

Even if the ﬂag bits were checked before executing a SLEEP instruction, it may be possible for ﬂag bits to become set before the SLEEP instruction completes. To determine whether a SLEEP instruction executed, test the PD

bit. If the PD bit is set, the SLEEP instruc-

tion was executed as a NOP. To ensure that the WDT is cleared, a CLR WDT instruc-

tion should be executed before a SLEEP instruction.

8.13 Program Veriﬁcation/Code Protection

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

Note: Microchip does not recommend code pro-

tecting windowed devices..

8.14 ID Locations

Four memory locations (2000h - 2003h) are designated as ID locations to store checksum or other code identiﬁcation numbers. These locations are not accessible during normal execution but are readable and writable only during program/verify. Only the 4 least signiﬁcant bits of ID location are usable.

For ROM devices, these values are submitted along with the ROM code.

8.15 In-Circuit Serial Programming

PIC16C84 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. Customers can manufacture boards with unprogrammed devices, and then program the microcontroller just before shipping the product, allowing the most recent ﬁrmware or custom ﬁrmware to be programmed.

The device is placed into a program/verify mode by holding the RB6 and RB7 pins low, while raising the MCLR

pin from VIL to VIHH (see

Memory Programming Speciﬁcation

PIC16C84 EEPROM

(DS30189)). RB6 becomes the programming clock and RB7 becomes the programming data. Both RB6 and RB7 are Schmitt Trigger inputs in this mode.

After reset, to place the device into programming/verify mode, the program counter (PC) points to location 00h. A 6-bit command is then supplied to the device, 14-bits of program data is then supplied to or from the device, using load or read-type instructions. For complete details of serial programming, please refer to the

cuit Serial Programming Guide

(DS30277).

In-Cir-

For ROM de vices, both the program memory and Data EEPROM memory may be read, but only the Data EEPROM memory may be programmed.

FIGURE 8-19: TYPICAL IN-SYSTEM SERIAL

PROGRAMMING CONNECTION

To Normal

External Connector Signals

+5V

VPP

CLK

Data I/O

Connections

PIC16CXX

V VSS MCLR/VPP

RB6

RB7

VDD

To Normal Connections

 1997 Microchip Technology Inc. DS30445C-page 49

PIC16C84

NOTES:

DS30445C-page 50  1997 Microchip Technology Inc.

PIC16C84

9.0 INSTRUCTION SET SUMMARY

Each PIC16CXX instruction is a 14-bit word divided into an OPCODE which speciﬁes the instruction type and one or more operands which further specify the operation of the instruction. The PIC16CXX instruction set summary in Table 9-2 lists byte-oriented, bit-ori- ented, and literal and control operations. Table 9-1 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 speciﬁes which ﬁle register is to be used by the instruction.

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

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 eight or eleven bit constant or literal value.

TABLE 9-1 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 x 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

d Destination select; d = 0: store result in W,

label Label name

TOS Top of Stack

PC Program Counter

PCLATH

GIE Global Interrupt Enable bit WDT Watchdog Timer/Counter

TO PD Power-down bit

dest Destination either the W register or the speciﬁed

[ ] Options

( )

→

< >

∈

talics

Microchip software tools.

d = 1: store result in ﬁle register f.

Default is d = 1

Program Counter High Latch

Time-out bit

Contents

Assigned to

In the set of

User deﬁned term (font is courier)

The instruction set is highly orthogonal and is grouped into three basic categories:

• Byte-oriented operations

• Bit-oriented operations

• Literal and control operations All instructions are executed within one single instruc-

tion cycle, unless a conditional test is true or the program counter is changed as a result of an instruction. In this case, the execution takes two instruction cycles with the second cycle executed as a NOP. One 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.

Table 9-2 lists the instructions recognized by the MPASM assembler.

Figure 9-1 shows the general formats that the instructions can have.

Note: To maintain upward compatibility with

future PIC16CXX products, do not use

the

OPTION and TRIS instructions.

All examples use the following format to represent a hexadecimal number:

0xhh

where h signiﬁes a hexadecimal digit.

FIGURE 9-1: GENERAL FORMAT FOR

INSTRUCTIONS

Byte-oriented ﬁle register operations

13 8 7 6 0

OPCODE d f (FILE #)

d = 0 for destination W d = 1 for destination f f = 7-bit ﬁle register address

Bit-oriented ﬁle register operations

13 10 9 7 6 0

OPCODE b (BIT #) f (FILE #)

b = 3-bit bit address f = 7-bit ﬁle register address

Literal and control operations

General

13 8 7 0

OPCODE k (literal)

k = 8-bit immediate value

CALL and GOTO instructions only

13 11 10 0

OPCODE k (literal)

k = 11-bit immediate value

 1998 Microchip Technology Inc. DS30445C-page 51

PIC16C84

TABLE 9-2 PIC16CXX INSTRUCTION SET

Mnemonic,

Operands

ADDWF ANDWF

CLRF

CLRW

COMF DECF

DECFSZ

INCF

INCFSZ

IORWF

MOVF

MOVWF

NOP

RLF

RRF SUBWF SWAPF XORWF

BCF

BSF

BTFSC BTFSS

ADDLW ANDLW

CALL

CLRWDT

GOTO

IORLW MOVLW RETFIE RETLW

RETURN

SLEEP SUBLW XORLW

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

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

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

k k k

k k

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

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

to the Timer0 Module.

3: If Program Counter (PC) is modiﬁed or a conditional test is true, the instruction requires two cycles. The second cycle is

executed as a NOP.

Description Cycles 14-Bit Opcode Status

MSb LSb

BYTE-ORIENTED FILE REGISTER OPERATIONS

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 nibbles in f

Exclusive OR W with f

BIT-ORIENTED FILE REGISTER OPERATIONS

Bit Clear f

Bit Set f

Bit Test f, Skip if Clear

Bit Test f, Skip if Set

LITERAL AND CONTROL OPERATIONS

Add literal and W

AND literal with W

Call subroutine

Clear Watchdog Timer

Go to address

Inclusive OR literal with W

Move literal to W

Return from interrupt

Return with literal in W

Return from Subroutine

Go into standby mode

Subtract W from literal

Exclusive OR literal with W

1 1 1 1 1 1

1(2)

1 1 1 1 1 1 1 1 1

1 1 (2) 1 (2)

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

01 01 01 01

11 11 10 00 10 11 11 00 11 00 00 11 11

0111 0101 0001 0001 1001 0011 1011 1010 1111 0100 1000 0000 0000 1101 1100 0010 1110 0110

00bb 01bb 10bb 11bb

111x 1001 0kkk 0000 1kkk 1000 00xx 0000 01xx 0000 0000 110x 1010

dfff dfff lfff 0xxx dfff dfff dfff dfff dfff dfff dfff lfff 0xx0 dfff dfff dfff dfff dfff

bfff bfff bfff bfff

kkkk kkkk kkkk 0110 kkkk kkkk kkkk 0000 kkkk 0000 0110 kkkk kkkk

ffff ffff ffff xxxx ffff ffff ffff ffff ffff ffff ffff ffff 0000 ffff ffff ffff ffff ffff

ffff ffff ffff ffff

kkkk kkkk kkkk 0100 kkkk kkkk kkkk 1001 kkkk 1000 0011 kkkk kkkk

Affected

C,DC,Z

Z Z Z Z Z

Z Z

C C

C,DC,Z

O,PD

TO,PD

C,DC,Z

Notes

1,2 1,2

1,2,3

1,2

1,2,3

1,2 1,2

1,2 1,2 1,2 1,2 1,2

1,2 1,2

3 3

DS30445C-page 52  1998 Microchip Technology Inc.

9.1 Instruction Descriptions

PIC16C84

ADDLW Add Literal and W

label

Syntax: [

] ADDLW k Operands: 0 ≤ k ≤ 255 Operation: (W) + k → (W) Status Affected: C, DC, Z Encoding: Description:

11 111x kkkk kkkk

The contents of the W register are added to the eight bit literal 'k' and the result is placed in the W register

. Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example:

Decode Read

literal 'k'

ADDLW 0x15

Process

data

Write to

Before Instruction

W = 0x10

After Instruction

W = 0x25

ANDLW AND Literal with W

label

Syntax: [

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

11 1001 kkkk kkkk

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

. Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

literal "k"

ANDLW 0x5F

Process

data

Write to

Before Instruction

W = 0xA3

After Instruction

W = 0x03

ADDWF Add W and f

label

Syntax: [

] ADDWF f,d

Operands: 0 ≤ f ≤ 127

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

00 0111 dfff ffff

Add the contents of the W register with

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

stored back in register 'f'

. Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

ADDWF FSR, 0

Process

data

'f'

Write to

destination

Before Instruction

W = 0x17 FSR = 0xC2

After Instruction

W = 0xD9 FSR = 0xC2

ANDWF AND W with f

label

Syntax: [

] ANDWF f,d

Operands: 0 ≤ f ≤ 127

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

00 0101 dfff ffff

AND the W register with register 'f'. If 'd'

is 0 the result is stored in the W regis-

ter. If 'd' is 1 the result is stored back in

. Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

ANDWF FSR, 1

Process

data

'f'

Write to

destination

Before Instruction

W = 0x17 FSR = 0xC2

After Instruction

W = 0x17 FSR = 0x02

 1998 Microchip Technology Inc. DS30445C-page 53

PIC16C84

BCF Bit Clear f

label

Syntax: [

] BCF f,b

Operands: 0 ≤ f ≤ 127

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

01 00bb bfff ffff

Description: Bit 'b' in register 'f' is cleared. Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

BCF FLAG_REG, 7

Process

data

'f'

Write

Before Instruction

FLAG_REG = 0xC7

After Instruction

FLAG_REG = 0x47

BTFSC Bit Test, Skip if Clear

label

Syntax: [

] BTFSC f,b

Operands: 0 ≤ f ≤ 127

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

01 10bb bfff ffff

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

instruction is executed.

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

instruction is discarded, and a NOP is

executed instead, making this a 2TCY

instruction

. Words: 1 Cycles: 1(2) Q Cycle Activity: Q1 Q2 Q3 Q4

Decode Read

Process

data

No-Operat

ion

If Skip: (2nd Cycle)

Q1 Q2 Q3 Q4

No-Operat

No-OperationNo-Opera

ion

tion

No-Operat

ion

BSF Bit Set f

label

Syntax: [

] BSF f,b

Operands: 0 ≤ f ≤ 127

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

01 01bb bfff ffff

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

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

BSF FLAG_REG, 7

Process

data

'f'

Write

Before Instruction

FLAG_REG = 0x0A

After Instruction

FLAG_REG = 0x8A

Example

HERE FALSE TRUE

BTFSC GOTO

•

Before Instruction

PC = address HERE

After Instruction

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

FLAG,1 PROCESS_CODE

DS30445C-page 54  1998 Microchip Technology Inc.

PIC16C84

BTFSS Bit Test f, Skip if Set

label

Syntax: [

] BTFSS f,b

Operands: 0 ≤ f ≤ 127

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

01 11bb bfff ffff

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

instruction is executed.

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

discarded and a NOP is executed

instead, making this a 2TCY instruction.

Words: 1 Cycles: 1(2) Q Cycle Activity: Q1 Q2 Q3 Q4

Decode Read

Process

data

No-Operat

ion

If Skip: (2nd Cycle)

Q1 Q2 Q3 Q4

Example

No-Operat

ion

HERE FALSE TRUE

No-OperationNo-Opera

BTFSC GOTO

•

FLAG,1 PROCESS_CODE

tion

No-Operat

ion

Before Instruction

PC = address HERE

After Instruction

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

CALL Call Subroutine

label

Syntax: [

] CALL k Operands: 0 ≤ k ≤ 2047 Operation: (PC)+ 1→ TOS,

k → PC<10:0>,

(PCLATH<4:3>) → PC<12:11> Status Affected: None Encoding: Description:

10 0kkk kkkk kkkk

Call Subroutine. First, return address

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

eleven bit immediate address is loaded

into PC bits <10:0>. The upper bits of

the PC are loaded from PCLATH. CALL

is a two cycle instruction.

Words: 1 Cycles: 2 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

1st Cycle

2nd Cycle

Decode Read

No-Opera

HERE CALL THERE

tion

literal 'k', Push PC

to Stack

No-Opera

tion

Process

data

No-Opera

tion

Write to

No-Operat

ion

Before Instruction

PC = Address HERE

After Instruction

PC = Address THERE TOS= Address HERE+1

 1998 Microchip Technology Inc. DS30445C-page 55

PIC16C84

CLRF Clear f

label

Syntax: [

] CLRF f Operands: 0 ≤ f ≤ 127 Operation: 00h → (f)

1 → Z Status Affected: Z Encoding: Description:

00 0001 1fff ffff

The contents of register 'f' are cleared

and the Z bit is set.

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

CLRF FLAG_REG

Process

data

'f'

Write

Before Instruction

FLAG_REG = 0x5A

After Instruction

FLAG_REG = 0x00 Z = 1

CLRW Clear W

label

Syntax: [

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

1 → Z Status Affected: Z Encoding: Description:

00 0001 0xxx xxxx

W register is cleared. Zero bit (Z) is

set.

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode No-Opera

CLRW

tion

Process

data

Write to

Before Instruction

W = 0x5A

After Instruction

W = 0x00 Z = 1

CLRWDT Clear Watchdog Timer

label

Syntax: [

] CLRWDT Operands: None Operation: 00h → WDT

0 → WDT prescaler,

1 → T

1 → PD Status Affected: TO, PD Encoding: Description:

00 0000 0110 0100

CLRWDT instruction resets the Watch-

dog Timer. It also resets the prescaler

of the WDT. Status bits TO and PD are

set.

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode No-Opera

CLRWDT

tion

Process

data

Clear WDT

Counter

Before Instruction

WDT counter = ?

After Instruction

WDT counter = 0x00 WDT prescaler= 0

TO = 1 PD = 1

DS30445C-page 56  1998 Microchip Technology Inc.

PIC16C84

COMF Complement f

label

Syntax: [

] COMF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f

) → (destination) Status Affected: Z Encoding: Description:

00 1001 dfff ffff

The contents of register 'f' are complemented. If 'd' is 0 the result is stored in W. If 'd' is 1 the result is stored back in register 'f'.

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

COMF REG1,0

Process

data

'f'

Write to

destination

Before Instruction

REG1 = 0x13

After Instruction

REG1 = 0x13 W = 0xEC

DECF Decrement f

label

Syntax: [

] DECF f,d

Operands: 0 ≤ f ≤ 127

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

00 0011 dfff ffff

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 Q Cycle Activity: Q1 Q2 Q3 Q4

Decode Read

Process

data

'f'

Write to

destination

DECFSZ Decrement f, Skip if 0

label

Syntax: [

] DECFSZ f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) - 1 → (destination);

skip if result = 0 Status Affected: None Encoding: Description:

00 1011 dfff ffff

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 1, the next instruction, is

executed. If the result is 0, then a NOP is

executed instead making it a 2T

tion.

CY instruc-

Words: 1 Cycles: 1(2) Q Cycle Activity: Q1 Q2 Q3 Q4

Decode Read

Process

data

Write to

destination

If Skip: (2nd Cycle)

Q1 Q2 Q3 Q4

Example

No-Operat

No-Opera

ion

HERE DECFSZ CNT, 1 GOTO LOOP CONTINUE •

•

tion

No-Operat

ion

No-Operati

Before Instruction

PC = address HERE

After Instruction

CNT = CNT - 1

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

Example

DECF CNT, 1

Before Instruction

CNT = 0x01 Z = 0

After Instruction

CNT = 0x00 Z = 1

 1998 Microchip Technology Inc. DS30445C-page 57

PIC16C84

GOTO Unconditional Branch

label

Syntax: [

] GOTO k Operands: 0 ≤ k ≤ 2047 Operation: k → PC<10:0>

PCLATH<4:3> → PC<12:11> Status Affected: None Encoding: Description:

10 1kkk kkkk kkkk

GOTO is an unconditional branch. The

eleven bit immediate value is loaded

into PC bits <10:0>. The upper bits of

PC are loaded from PCLATH<4:3>.

GOTO is a two cycle instruction.

Words: 1 Cycles: 2 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

1st Cycle

2nd Cycle

Decode Read

No-Operat

GOTO THERE

ion

literal 'k'

No-Operat

ion

Process

data

No-Opera

tion

Write to

No-Operat

ion

After Instruction

PC = Address THERE

INCF Increment f

label

Syntax: [

] INCF f,d

Operands: 0 ≤ f ≤ 127

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

00 1010 dfff ffff

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 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

INCF CNT, 1

Process

data

'f'

Write to

destination

Before Instruction

CNT = 0xFF Z = 0

After Instruction

CNT = 0x00 Z = 1

DS30445C-page 58  1998 Microchip Technology Inc.

PIC16C84

INCFSZ Increment f, Skip if 0

label

Syntax: [

] INCFSZ f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) + 1 → (destination),

skip if result = 0 Status Affected: None Encoding: Description:

00 1111 dfff ffff

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 1, the next instruction is

executed. If the result is 0, a NOP is exe-

cuted instead making it a 2TCY instruc-

tion

. Words: 1 Cycles: 1(2) Q Cycle Activity: Q1 Q2 Q3 Q4

Decode Read

Process

data

Write to

destination

If Skip: (2nd Cycle)

Q1 Q2 Q3 Q4

No-Operat

No-Opera

ion

tion

No-Opera

tion

No-Operati

IORLW Inclusive OR Literal with W

label

Syntax: [

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

11 1000 kkkk kkkk

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

. Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

literal 'k'

IORLW 0x35

Process

data

Write to

Before Instruction

W = 0x9A

After Instruction

W = 0xBF Z = 1

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

 1998 Microchip Technology Inc. DS30445C-page 59

PIC16C84

IORWF Inclusive OR W with f

label

Syntax: [

] IORWF f,d

Operands: 0 ≤ f ≤ 127

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

00 0100 dfff ffff

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 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

IORWF RESULT, 0

Process

data

'f'

Write to

destination

Before Instruction

RESULT = 0x13 W = 0x91

After Instruction

RESULT = 0x13 W = 0x93 Z = 1

MOVLW Move Literal to W

label

Syntax: [

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

11 00xx kkkk kkkk

The eight bit literal 'k' is loaded into W register

. The don’t cares will assemble

as 0’s.

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

literal 'k'

MOVLW 0x5A

Process

data

Write to

After Instruction

W = 0x5A

MOVF Move f

label

Syntax: [

] MOVF f,d

Operands: 0 ≤ f ≤ 127

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

00 1000 dfff ffff

The contents of register f is moved to a

destination dependant upon the status

of d. If d = 0, destination is W register . If

d = 1, the destination is ﬁle register f

itself. d = 1 is useful to test a ﬁle regis-

ter since status ﬂag Z is affected.

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

MOVF FSR, 0

Process

data

'f'

Write to

destination

After Instruction

W = value in FSR register Z = 1

MOVWF Move W to f

label

Syntax: [

] MOVWF f Operands: 0 ≤ f ≤ 127 Operation: (W) → (f) Status Affected: None Encoding: Description:

00 0000 1fff ffff

Move data from W register to register 'f'

. Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

MOVWF OPTION_REG

Process

data

'f'

Write

Before Instruction

OPTION = 0xFF W = 0x4F

After Instruction

OPTION = 0x4F W = 0x4F

DS30445C-page 60  1998 Microchip Technology Inc.

PIC16C84

NOP No Operation

label

Syntax: [

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

00 0000 0xx0 0000

No operation.

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode No-Opera

NOP

tion

No-Opera

tion

No-Operat

ion

OPTION Load Option Register

Syntax: [

label

] OPTION

Operands: None

Operation: (W) → OPTION Status Affected: None Encoding: Description:

00 0000 0110 0010

The contents of the W register are loaded in the OPTION register. This instruction is supported for code compatibility with PIC16C5X products. Since OPTION is a readable/writable register, the user can directly address it.

Words: 1 Cycles: 1

Example

To maintain upward compatibility

with future PIC16CXX products,

do not use this instruction.

RETFIE Return from Interrupt

label

Syntax: [

] RETFIE Operands: None Operation: TOS → PC,

1 → GIE Status Affected: None Encoding: Description:

00 0000 0000 1001

Return from Interrupt. Stack is POPed

and Top of Stack (TOS) is loaded in the

PC. Interrupts are enabled by setting

Global Interrupt Enable bit, GIE

(INTCON<7>). This is a two cycle

instruction.

Words: 1 Cycles: 2 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

1st Cycle

2nd Cycle

Decode No-Opera

No-Operat

ion

RETFIE

tion

No-Opera

tion

Set the

GIE bit

No-Opera

tion

Pop from the Stack

No-Operat

ion

After Interrupt

PC = TOS GIE = 1

 1998 Microchip Technology Inc. DS30445C-page 61

PIC16C84

RETLW Return with Literal in W

label

Syntax: [

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

TOS → PC Status Affected: None Encoding: Description:

11 01xx kkkk kkkk

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 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

1st Cycle

2nd Cycle

TABLE

Decode Read

No-Operat

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

ion

literal 'k'

No-Opera

tion

No-Opera

tion

No-Opera

tion

Write to W ,

Pop from the Stack

No-Operat

ion

Before Instruction

W = 0x07

After Instruction

W = value of k8

RETURN Return from Subroutine

label

Syntax: [

] RETURN Operands: None Operation: TOS → PC Status Affected: None Encoding: Description:

00 0000 0000 1000

Return from subroutine. The stack is POPed and the top of the stack (TOS) is loaded into the program counter. This is a two cycle instruction.

Words: 1 Cycles: 2 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

1st Cycle

2nd Cycle

Decode No-Opera

No-Operat

RETURN

No-Opera

ion

tion

No-Opera

tion

No-Opera

tion

Pop from the Stack

No-Opera

tion

After Interrupt

PC = TOS

DS30445C-page 62  1998 Microchip Technology Inc.

PIC16C84

RLF Rotate Left f through Carry

label

Syntax: [

] RLF f,d

Operands: 0 ≤ f ≤ 127

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

00 1101 dfff ffff

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 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

RLF REG1,0

Process

data

'f'

Write to

destination

Before Instruction

REG1 = 1110 0110 C = 0

After Instruction

REG1 = 1110 0110 W = 1100 1100 C = 1

RRF Rotate Right f through Carry

label

Syntax: [

] RRF f,d

Operands: 0 ≤ f ≤ 127

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

00 1100 dfff ffff

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 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

RRF REG1,0

Process

data

'f'

Write to

destination

Before Instruction

REG1 = 1110 0110 C = 0

After Instruction

REG1 = 1110 0110 W = 0111 0011 C = 0

 1998 Microchip Technology Inc. DS30445C-page 63

PIC16C84

SLEEP

Syntax: [

label

] SLEEP Operands: None Operation: 00h → WDT,

0 → WDT prescaler,

1 → T

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

00 0000 0110 0011

The power-down status bit, PD is

cleared. Time-out status bit, TO is

set. Watchdog Timer and its prescaler

are cleared.

The processor is put into SLEEP

mode with the oscillator stopped. See

Section 14.8 for more details.

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Decode No-Opera

tion

No-Opera

tion

Go to Sleep

Example: SLEEP

SUBLW Subtract W from Literal

label

Syntax: [

] SUBLW k Operands: 0 ≤ k ≤ 255 Operation: k - (W) → (W) Status Affected: C, DC, Z Encoding: 11 110x kkkk kkkk Description:

The W register is subtracted (2’s complement method) from the eight bit literal 'k'. The result is placed in the W register.

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Decode Read

literal 'k'

Process

data

Write to W

Example 1: SUBLW 0x02

Before Instruction

W = 1 C = ? Z = ?

After Instruction

W = 1 C = 1; result is positive Z = 0

Example 2: Before Instruction

W = 2 C = ? Z = ?

After Instruction

W = 0 C = 1; result is zero Z = 1

Example 3: Before Instruction

W = 3 C = ? Z = ?

After Instruction

W = 0xFF C = 0; result is negative Z = 0

DS30445C-page 64  1998 Microchip Technology Inc.

PIC16C84

SUBWF Subtract W from f

label

Syntax: [

] SUBWF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1] Operation: (f) - (W) → (destination) Status Affected: C, DC, Z Encoding: 00 0010 dfff ffff Description:

Subtract (2’s complement method) W reg-

ister 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 Q Cycle Activity: Q1 Q2 Q3 Q4

Decode Read

Process

data

Write to

destination

Example 1: SUBWF REG1,1

Before Instruction

REG1 = 3 W = 2 C = ? Z = ?

After Instruction

REG1 = 1 W = 2 C = 1; result is positive Z = 0

Example 2: Before Instruction

REG1 = 2 W = 2 C = ? Z = ?

After Instruction

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

Example 3: Before Instruction

REG1 = 1 W = 2 C = ? Z = ?

After Instruction

REG1 = 0xFF W = 2 C = 0; result is negative Z = 0

SWAPF Swap Nibbles in f

label

Syntax: [

] SWAPF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f<3:0>) → (destination<7:4>),

(f<7:4>) → (destination<3:0>)

Status Affected: None

Encoding: 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'.

1110 dfff ffff

Words: 1 Cycles: 1 Q Cycle Activity: Q1 Q2 Q3 Q4

Example

Decode Read

SWAPF REG, 0

Process

data

Write to

destination

Before Instruction

REG1 = 0xA5

After Instruction

REG1 = 0xA5 W = 0x5A

TRIS Load TRIS Register

Syntax: [

label

] TRIS f Operands: 5 ≤ f ≤ 7 Operation: (W) → TRIS register f; Status Affected: None Encoding: Description:

0000 0110 0fff

The instruction is supported for code compatibility with the PIC16C5X products. Since TRIS registers are readable and writable, the user can directly address them.

Words: 1 Cycles: 1

Example

To maintain upward compatibility

with future PIC16CXX products,

do not use this instruction.

 1998 Microchip Technology Inc. DS30445C-page 65

PIC16C84

XORLW Exclusive OR Literal with W

Syntax: [

label

] XORLW k Operands: 0 ≤ k ≤ 255 Operation: (W) .XOR. k → (W) Status Affected: Z Encoding: 11 1010 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 Q Cycle Activity: Q1 Q2 Q3 Q4

Decode Read

literal 'k'

Process

data

Write to

Example: XORLW 0xAF

Before Instruction

W = 0xB5

After Instruction

W = 0x1A

XORWF Exclusive OR W with f

label

Syntax: [

] XORWF f,d

Operands: 0 ≤ f ≤ 127

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

00 0110 dfff ffff

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 Q Cycle Activity: Q1 Q2 Q3 Q4

Decode Read

Example XORWF

'f'

REG 1

Process

data

Write to

destination

Before Instruction

REG = 0xAF W = 0xB5

After Instruction

REG = 0x1A W = 0xB5

DS30445C-page 66  1998 Microchip Technology Inc.

PIC16C84

10.0 DEVELOPMENT SUPPORT

10.1 Development Tools

The PICmicrο microcontrollers are supported with a full range of hardware and software dev elopment tools:



• PICMASTER In-Circuit Emulator

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

• PRO MATE

• PICSTART 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)

10.2 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 SX, 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 availab le for

European Union (EU) countries.

/PICMASTER CE Real-Time



II Universal Programmer



Plus Entry-Level Prototype

10.3 ICEPIC: Low-Cost PICmicro™ In-Circuit Emulator

ICEPIC is a low-cost in-circuit emulator solution for the Microchip PIC12CXXX, PIC16C5X and PIC16CXXX families of 8-bit OTP microcontrollers.

ICEPIC is designed to operate on PC-compatible machines ranging from 286-AT based machines under Windows 3.x environment. ICEPIC features real time, non-intrusive emulation.



through Pentium

10.4 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 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 PIC12CXXX, PIC14C000, PIC16C5X, PIC16CXXX and PIC17CXX devices. It can also set conﬁguration and code-protect bits in this mode.

DD and VPP

10.5 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 PIC12CXXX, PIC14C000, 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.



 1997 Microchip Technology Inc. DS30445A - page 67

PIC16C84

10.6 PICDEM-1 Low-Cost PICmicro 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-Plus 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.

10.7 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-Plus, 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 f eatures include a RS-232 interface, push-button switches, a potentiometer for simulated analog input, a Serial EEPROM to demonstrate usage of the I tion to an LCD module and a keypad.

C bus and separate headers for connec-

10.8 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.

10.9 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 PICmicro 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.

10.10 Assembler (MPASM)

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

MPASM offers full featured Macro capabilities, conditional assembly , and se ver al source and listing formats. 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.

DS30445A - page 68  1997 Microchip Technology Inc.

PIC16C84

MPASM has the follo wing features 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 PICmicro. Directives are helpful in making the development of y our assemble source code shorter and more maintainable.

10.11 Software Simulator (MPLAB-SIM)

The MPLAB-SIM Software Simulator allows code development in a PC host environment. It allows the user to simulate the PICmicro 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 , ex ecute 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.

10.12 C Compiler (MPLAB-C)

10.14 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 PICmicro 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 o wn code. MP-DriveWay is intelligent enough to maintain your code through subsequent code generation.

10.15 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 tradeoff analysis and reliability calculations. The total kit can signiﬁcantly reduce time-to-market and result in an optimized system.

10.16 KEELOQ Evaluation and Programming Tools

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

The MPLAB-C Code Development System is a complete ‘C’ compiler and integrated development environment for Microchip’s PICmicro™ 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.

10.13 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, menting more complex systems.

Both versions include Microchip’s stration board for hands-on experience with fuzzy logic systems implementation.

fuzzy

TECH-MP, edition for imple-

fuzzy

LAB demon-

 1997 Microchip Technology Inc. DS30445A - page 69

PIC16C84

TABLE 10-1: DEVELOPMENT TOOLS FROM MICROCHIP

HCS200

HCS300

HCS301

24CXX

25CXX

93CXX

3Q97

Available

✔

PIC12C5XX PIC14000 PIC16C5X PIC16CXXX PIC16C6X PIC16C7XX PIC16C8X PIC16C9XX PIC17C4X PIC17C75X



✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

✔ ✔ ✔ ✔ ✔ ✔

✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

-MP



TECH

✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

✔ ✔ ✔ ✔ ✔ ✔

✔ ✔

✔ ✔ ✔ ✔

✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔



✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔



✔ ✔ ✔ ✔



Explorer/Edition

Fuzzy Logic

PICMASTER-CE

In-Circuit Emulator

PICMASTER

DS30445A - page 70  1997 Microchip Technology Inc.

ICEPIC Low-Cost

In-Circuit Emulator

MPLAB

Integrated

Development

Emulator Products

Environment

MPLAB C

Compiler

fuzzy

Dev. Tool

MP-DriveWay

Applications

Code Generator

Software Tools

Total Endurance

Software Model

PICSTART

Lite Ultra Low-Cost

Dev. Kit

PICSTART

Plus Low-Cost

Universal Dev. Kit

PRO MATE

KEELOQ

Universal

Programmer

Programmers

SEEVAL

Designers Kit

PICDEM-1

PICDEM-2

PICDEM-3

Demo Boards

KEELOQ

Evaluation Kit

PIC16C84

11.0 ELECTRICAL CHARACTERISTICS FOR PIC16C84

Absolute Maximum Ratings †

Ambient temperature under bias.............................................................................................................-55°C to +125°C

Storage temperature.............................................................................................................................. -65°C to +150°C

Voltage on V Voltage on MCLR Voltage on all other pins with respect to V Total power dissipation Maximum current out of V Maximum current into V Input clamp current, I Output clamp current, I

Maximum output current sunk by any I/O pin..........................................................................................................25 mA

Maximum output current sourced by any I/O pin ....................................................................................................20 mA

Maximum current sunk by PORTA ..........................................................................................................................80 mA

Maximum current sourced by PORTA.....................................................................................................................50 mA

Maximum current sunk by PORTB........................................................................................................................150 mA

Maximum current sourced by PORTB...................................................................................................................100 mA

Note 1: Power dissipation is calculated as follows: Pdis = V Note 2: Voltage spik es below V

† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this speciﬁcation is not implied. Exposure to maximum rating conditions f or extended periods may affect device reliability.

DD with respect to VSS ............................................................................................................ -0.3 to +7.5V

with respect to VSS

(1)

.....................................................................................................................................800 mW

SS pin ...........................................................................................................................150 mA

DD pin..............................................................................................................................100 mA

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

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

a series resistor of 50-100Ω should be used when applying a “low” le vel to the MCLR this pin directly to V

(2)

...................................................................................................... -0.3 to +14V

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

DD x {IDD - ∑ IOH} + ∑ {(VDD-VOH) x IOH} + ∑(VOl x IOL)

SS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up . Thus,

pin rather than pulling

SS.

 1997 Microchip Technology Inc. DS30445C-page 71

PIC16C84

TABLE 11-1 CROSS REFERENCE OF DEVICE SPECS FOR OSCILLATOR CONFIGURATIONS

AND FREQUENCIES OF OPERATION (COMMERCIAL DEVICES)

OSC PIC16C84-04 PIC16C84-10 PIC16LC84-04

RC VDD: 4.0V to 6.0V

IDD: 4.5 mA max. at 5.5V IPD: 100 µA max. at 4.0V WDT dis Freq: 4.0 MHz max.

XT V

HS VDD: 4.5V to 5.5V

The shaded sections indicate oscillator selections which are tested for functionality, but not for MIN/MAX speciﬁcations. It is recommended that the user select the device type that ensures the speciﬁcations required.

DD: 4.0V to 6.0V

IDD: 4.5 mA max. at 5.5V IPD: 100 µA max. at 4.0V WDT dis Freq: 4.0 MHz max.

IDD: 4.5 mA typ. at 5.5V IPD: 40.0 µA typ. at 4.5V WDT dis Freq: 4.0 MHz max.

VDD: 4.0V to 6.0V IDD: 60 µA typ. at 32 kHz, 2.0V IPD: 26 µA typ. at 2.0V WDT dis Freq: 200 kHz max.

VDD: 4.5V to 5.5V IDD: 1.8 mA typ. at 5.5V IPD: 40.0 µA typ. at 4.5V WDT dis Freq: 4.0 MHz max.

VDD: 4.5V to 5.5V IDD: 10 mA max. at 5.5V typ. IPD: 40.0 µA typ. at 4.5V WDT dis Freq: 10 MHz max.

Do not use in LP mode VDD: 2.0V to 6.0V

VDD: 2.0V to 6.0V IDD: 4.5 mA max. at 5.5V IPD: 100 µA max. at 4V WDT dis Freq: 2.0 MHz max.

Do not use in HS mode

IDD: 400 µA max. at 32 kHz, 2.0V IPD: 100 µA max. at 4.0V WDT dis Freq: 200 kHz max.

DS30445C-page 72  1997 Microchip Technology Inc.

11.1 DC CHARACTERISTICS: PIC16C84-04 (Commercial, Industrial)

PIC16C84-10 (Commercial, Industrial)

PIC16C84

DC Characteristics Power Supply Pins

Parame-

ter No.

D001

Sym Characteristic Min Typ† Max Units Conditions

DD Supply Voltage 4.0

D001A D002 V

D003 V

DR RAM Data Retention

POR VDD start voltage to

Voltage

(1)

Standard Operating Conditions (unless otherwise stated)

Operating temperature 0°C ≤ T

-40°C ≤ T

6.0

4.5——

5.5VV

A ≤ +70°C (commercial) A ≤ +85°C (industrial)

XT, RC and LP osc conﬁguration HS osc conﬁguration

1.5* — — V Device in SLEEP mode

— VSS — V See section on Power-on Reset for details ensure internal Power-on Reset signal

D004 S

VDD VDD rise rate to ensure

0.05* — — V/ms See section on Power-on Reset for details internal Power-on Reset signal

D010 D010A

DD Supply Current

(2)

— —

1.8

7.3

4.5 10

RC and XT osc conﬁguration mA mA

FOSC = 4 MHz, VDD = 5.5V F

OSC = 4 MHz, VDD = 5.5V

(4)

(During EEPROM programming)

HS osc conﬁguration (PIC16C84-10)

D013 D020

D021 D021A

PD Power-down Current

(3)

— —

5.0 40

38 38

100 100 100

µA µA µA

OSC = 10 MHz, VDD = 5.5V

VDD = 4.0V, WDT enabled, industrial V

DD = 4.0V, WDT disabled, commercial

DD = 4.0V, WDT disabled, industrial

* These parameters are characterized but not tested. † Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only

and are not tested.

Note 1: This is the limit to which V

DD can be lowered in SLEEP mode without losing RAM data.

2: The supply current is mainly a function of the operating voltage and frequency. Other factors such as I/O pin

loading and switching rate, oscillator type, internal code execution pattern, and temperature also have an impact on current consumption. The test conditions for all I OSC1 = external square wave, from rail to rail; all I/O pins tristated, pulled to V MCLR

= VDD; WDT enabled/disabled as speciﬁed.

DD measurements in active operation mode are:

DD, T0CKI = VDD,

3: The power down current in SLEEP mode does not depend on the oscillator type. Power-down current is

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

DD or VSS.

4: For RC osc conﬁguration, current through Rext is not included. The current through the resistor can be

estimated by the formula I

R = VDD/2Rext (mA) with Rext in kOhm.

 1997 Microchip Technology Inc. DS30445C-page 73

PIC16C84

11.2 DC CHARACTERISTICSPIC16LC84-04 (Commercial, Industrial)

DC Characteristics Power Supply Pins

Parameter

No.

D001 V D002 V

D003 V

Sym Characteristic Min Typ† Max Units Conditions

DD Supply Voltage 2.0 — 6.0 V XT, RC, and LP osc conﬁguration DR RAM Data Retention

POR VDD start voltage to

Voltage

(1)

Standard Operating Conditions (unless otherwise stated)

Operating temperature 0°C ≤ T

-40°C ≤ T

A ≤ +70°C (commercial) A ≤ +85°C (industrial)

1.5 * — — V Device in SLEEP mode

— VSS — V See section on Power-on Reset for details ensure internal Power-on Reset signal

D004 S

VDD VDD rise rate to ensure

0.05* — — V/ms See section on Power-on Reset for details internal Power-on Reset signal

D010 D010A

DD Supply Current

(2)

— —

7.3

RC and XT osc conﬁguration

mA mA

FOSC = 2 MHz, VDD = 5.5V F

OSC = 2 MHz, VDD = 5.5V

(4)

(During EEPROM programming)

LP osc conﬁguration

D014

—

400

µA

OSC = 32 kHz, VDD = 2.0V,

WDT disabled

D020 D021 D021A

PD Power-down Current

(3)

— — —

26 26 26

100 100 100

µA

VDD = 2.0V, WDT enabled, industrial

µA

DD = 2.0V, WDT disabled, commercial

µA

DD = 2.0V, WDT disabled, industrial

* These parameters are characterized but not tested. † Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only

and are not tested.

Note 1: This is the limit to which V

DD can be lowered in SLEEP mode without losing RAM data.

2: The supply current is mainly a function of the operating voltage and frequency. Other factors such as I/O pin

loading and switching rate, oscillator type, internal code execution pattern, and temperature also have an impact on the current consumption. The test conditions for all I OSC1=external square wave, from rail to rail; all I/O pins tristated, pulled to V MCLR

= VDD; WDT enabled/disabled as speciﬁed.

DD measurements in active operation mode are:

DD, T0CKI = VDD,

3: The power down current in SLEEP mode does not depend on the oscillator type. Power-down current is

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

DD or VSS.

4: For RC osc conﬁguration, current through Rext is not included. The current through the resistor can be

estimated by the formula I

R = VDD/2Rext (mA) with Rext in kOhm.

DS30445C-page 74  1997 Microchip Technology Inc.

PIC16C84

11.3 DC CHARACTERISTICS: PIC16C84-04 (Commercial, Industrial) PIC16C84-10 (Commercial, Industrial) PIC16LC84-04 (Commercial, Industrial)

Standard Operating Conditions (unless otherwise stated) DC Characteristics All Pins Except Power Supply Pins

Parameter

No.

Sym Characteristic Min Typ† Max Units Conditions

Input Low Voltage

IL I/O ports

V D030 with TTL buffer V D030A V D031 with Schmitt Trigger buffer VSS — 0.2VDD V entire range D032 MCLR

, RA4/T0CKI, OSC1

(RC mode)

D033 OSC1 (XT, HS and LP modes)

Input High Voltage

IH I/O ports

D040 with TTL buffer 0.36V D040A 0.48V D041 with Schmitt Trigger buffer 0.45VDD — VDD entire range D042 MCLR

, RA4/T0CKI, OSC1

(RC mode) D043 OSC1 (XT, HS and LP modes) D070 I

PURB PORTB weak pull-up current 50* 250* 400* µA VDD = 5V, VPIN = VSS

Input Leakage Current

(2,3)

D060 IIL I/O ports — — ±1 µA Vss ≤ VPIN ≤ VDD,

D061 MCLR

, RA4/T0CKI — — ±5 µA Vss ≤ VPIN ≤ VDD

D063 OSC1/CLKIN — — ±5 µA Vss ≤ VPIN ≤ VDD, XT, HS and LP

Output Low Voltage

D080 V

OL I/O ports — — 0.6 V IOL = 8.5 mA, VDD = 4.5V

D083 OSC2/CLKOUT — — 0.6 V I

(RC osc conﬁguration)

Output High Voltage

D090 V

OH I/O ports

(3)

D093 OSC2/CLKOUT V

(RC osc conﬁguration)

* These parameters are characterized but not tested. † Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only

and are not tested.

Note 1: In RC oscillator conﬁguration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended that the

PIC16C84 be driven with external clock in RC mode.

2: The leakage current on the MCLR

pin is strongly dependent on the applied voltage lev el. The speciﬁed lev els

represent normal operating conditions. Higher leakage current may be measured at different input voltages. 3: Negative current is deﬁned as coming out of the pin. 4: The user may use better of the two specs.

Operating temperature 0°C ≤ T

-40°C ≤ T

Operating voltage V

DD range as described in DC spec

A ≤ +70°C (commercial) A ≤ +85°C (industrial)

Section 11-1 and Section 11.2.

SS — 0.8 V 4.5 ≤ VDD ≤ 5.5V SS — 0.16VDD V entire range

(4)

Vss — 0.2VDD V

(1)

Vss — 0.3VDD V

DD — VDD V 4.5 ≤ VDD ≤ 5.5V DD entire range

(4)

0.85VDD — VDD V

(1)

0.7VDD — VDD V

Pin at hi-impedance

osc conﬁguration

OL = 1.6 mA, VDD = 4.5V

VDD - 0.7 — — V IOH = -3.0 mA, VDD = 4.5V

DD - 0.7 — — V IOH = -1.3 mA, VDD = 4.5V

 1997 Microchip Technology Inc. DS30445C-page 75

PIC16C84

11.4 DC CHARACTERISTICS: PIC16C84-04 (Commercial, Industrial) PIC16C84-10 (Commercial, Industrial) PIC16LC84-04 (Commercial, Industrial)

Standard Operating Conditions (unless otherwise stated) DC Characteristics All Pins Except Power Supply Pins

Parameter

No.

Sym Characteristic Min Typ† Max Units Conditions

Capacitive Loading Specs on Output Pins

D100 C

D101 C

OSC2 OSC2/CLKOUT pin — — 15 pF In XT, HS and LP modes when

IO All I/O pins and OSC2

(RC mode)

Data EEPROM Memory

D120 E D121 V

D122 T

D Endurance 1M 10M DRW VDD for read/write VMIN — 6.0 V VMIN = Minimum operating

DEW Erase/Write cycle time

(1)

Program EEPROM Memory

D130 E D131 V

D132 V D133 T

P Endurance 100 1000 — E/W PR VDD for read VMIN — 6.0 V VMIN = Minimum operating

PEW VDD for erase/write 4.5 — 5.5 V PEW Erase/Write cycle time

(1)

* These parameters are characterized but not tested. † Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only

and are not tested.

Note 1: The user should use interrupts or poll the EEIF or WR bits to ensure the write cycle has completed.

Operating temperature 0°C ≤ T

-40°C ≤ T

Operating voltage V

DD range as described in DC spec Section 11-1

and Section 11.2.

— — 50 pF

—

E/W 25°C at 5V

— 10 20* ms

— 10 — ms

A ≤ +70°C (commercial) A ≤ +85°C (industrial)

external clock is used to drive OSC1.

voltage

DS30445C-page 76  1997 Microchip Technology Inc.

TABLE 11-2 TIMING PARAMETER SYMBOLOGY

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

1. TppS2ppS

2. TppS

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

2 to os,osc OSC1 ck CLKOUT ost oscillator start-up timer cy cycle time pwrt power-up timer io I/O port rbt RBx pins inp INT pin t0 T0CKI mc MCLR Uppercase symbols and their meanings:

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

wdt watchdog timer

PIC16C84

FIGURE 11-1: PARAMETER MEASUREMENT INFORMATION

DD XTAL

0.7 V

0.8 VDD RC

0.3 V

DD XTAL

0.15 V

DD RC

OSC1 Measurement Points I/O Port Measurement Points

(High)

(Low)

All timings are measured between high and low measurement points as indicated in the ﬁgure.

FIGURE 11-2: LOAD CONDITIONS

Load Condition 1 Load Condition 2

VDD/2

RL = 464Ω

L = 50 pF for all pins except OSC2.

15 pF for OSC2 output.

VSS

2.0 VDD (High)

0.2 V

DD (Low)

 1997 Microchip Technology Inc. DS30445C-page 77

PIC16C84

11.5 Timing Diagrams and Speciﬁcations

FIGURE 11-3: EXTERNAL CLOCK TIMING

OSC1

CLKOUT

Q1 Q2

1 3 3 4 4

Q3 Q4 Q1

TABLE 11-3 EXTERNAL CLOCK TIMING REQUIREMENTS

Parameter

No. Sym Characteristic Min Typ† Max Units Conditions

(1)

DC — 2 MHz XT, RC osc PIC16LC84-04 DC — 4 MHz XT, RC osc PIC16C84-04 DC — 10 MHz HS osc PIC16C84-10 DC — 200 kHz LP osc PIC16LC84-04

DC — 2 MHz RC osc PIC16LC84-04 DC — 4 MHz RC osc PIC16C84-04

0.1 — 2 MHz XT osc PIC16LC84-04

0.1 — 4 MHz XT osc PIC16C84-04 1 — 10 MHz HS osc PIC16C84-10

DC — 200 kHz LP osc PIC16LC84-04

500 — — ns XT, RC osc PIC16LC84-04 250 — — ns XT, RC osc PIC16C84-04 100 — — ns HS osc PIC16C84-10

5 — — µs LP osc PIC16LC84-04

500 250

500 — 10,000 ns XT osc PIC16LC84-04 250 — 10,000 ns XT osc PIC16C84-04 100 — 1,000 ns HS osc PIC16C84-10

0.4 4/Fosc DC µs

60 * — — ns XT osc PIC16LC84-04 50 * — — ns XT osc PIC16C84-04

2 * — — µs LP osc PIC16LC84-04

35 * — — ns HS osc PIC16C84-10

50 * — — ns LP osc PIC16LC84-04 15 * — — ns HS osc PIC16C84-10

— —

5 — — µs LP osc PIC16LC84-04

— —

nsnsRC osc PIC16LC84-04

RC osc PIC16C84-04

FOSC External CLKIN Frequency

Oscillator Frequency

1 Tosc External CLKIN Period

Oscillator Period

2 TCY Instruction Cycle Time 3 TosL,

4 TosR,

* These parameters are characterized but not tested. † Data in "Typ" column is at 5.0V, 25˚C unless otherwise stated. These parameters are for design guidance only and are not

tested.

Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All speciﬁed values are based on

characterization data for that particular oscillator type under standard operating conditions with the device ex ecuting code. Exceeding these speciﬁed limits may result in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to operate at "min." values with an external clock applied to the OSC1 pin. When an external clock input is used, the "Max." cycle time limit is "DC" (no clock) for all devices.

Clock in (OSC1) High or Low

TosH

Time

Clock in (OSC1) Rise or Fall Time 25 * — — ns XT osc PIC16C84-04

TosF

(1)

DS30445C-page 78  1997 Microchip Technology Inc.

FIGURE 11-4: CLKOUT AND I/O TIMING

PIC16C84

20, 21

OSC1

CLKOUT

I/O Pin (input)

I/O Pin (output)

old value

Note: All tests must be done with speciﬁed capacitive loads (Figure 11-2) 50 pF on I/O pins and CLKOUT.

TABLE 11-4 CLKOUT AND I/O TIMING REQUIREMENTS

Parameter

No. Sym Characteristic Min Typ† Max Units Conditions

10 TosH2ckL OSC1↑ to CLKOUT↓ PIC16C84 — 15 30 * ns Note 1

10A PIC16LC84 — 15 120 * ns Note 1

11 TosH2ckH OSC1↑ to CLKOUT↑ PIC16C84 — 15 30 * ns Note 1

11A PIC16LC84 — 15 120 * ns Note 1

12 TckR CLKOUT rise time PIC16C84 — 15 30 * ns Note 1

12A PIC16LC84 — 15 100 * ns Note 1

13 TckF CLKOUT fall time PIC16C84 — 15 30 * ns Note 1

13A PIC16LC84 — 15 100 * ns Note 1

14 TckL2ioV CLKOUT ↓ to Port out valid — — 0.5T 15 TioV2ckH Port in valid before PIC16C84 0.30TCY + 30 * — — ns Note 1

CLKOUT ↑ PIC16LC84 0.30TCY + 80 * — — ns Note 1 16 TckH2ioI Port in hold after CLKOUT ↑ 0 * — — ns Note 1 17 TosH2ioV OSC1↑ (Q1 cycle) to PIC16C84 — — 125 * ns

Port out valid PIC16LC84 — — 250 * ns 18 TosH2ioI OSC1↑ (Q2 cycle) to Port input invalid

(I/O in hold time) 19 TioV2osH Port input valid to OSC1↑

(I/O in setup time) 20 TioR Port output rise time PIC16C84 — 10 25 * ns

20A PIC16LC84 — 10 60 * ns

21 TioF Port output fall time PIC16C84 — 10 25 * ns

21A PIC16LC84 — 10 60 * ns

22 Tinp INT pin high PIC16C84 20 * — — ns

22A or low time PIC16LC84 55 * — — ns

23 Trbp RB7:RB4 change INT PIC16C84 20 * — — ns

23A high or low time PIC16LC84 55 * — — ns

* These parameters are characterized but not tested. † Data in "Typ" column is at 5.0V, 25˚C unless otherwise stated. These parameters are for design guidance only and are not

tested.

Note 1: Measurements are taken in RC Mode where CLKOUT output is 4 x TOSC.

Q2 Q3

CY +20 * ns Note 1

TBD — — ns

new value

 1997 Microchip Technology Inc. DS30445C-page 79

PIC16C84

FIGURE 11-5: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP

TIMER TIMING

VDD

MCLR

Internal

POR

PWRT

Time-out

OSC

Time-out

Internal

RESET

Watchdog

Timer

RESET

I/O Pins

TABLE 11-5 RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP

TIMER REQUIREMENTS

Parameter

No.

30 TmcL MCLR Pulse Width (low) 350 *

31 Twdt Watchdog Timer Time-out Period

32 Tost Oscillation Start-up Timer Period — 1024TOSC — ms TOSC = OSC1 period 33 Tpwrt Power-up Timer Period 28 * 72 132 * ms VDD = 5.0V

34 TIOZ I/O Hi-impedance from MCLR Low

* These parameters are characterized but not tested. † Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not

tested.

Sym Characteristic Min Typ† Max Units Conditions

(No Prescaler)

or reset

—

150 *

7 * 18 33 * ms VDD = 5V

— — 100 * ns

—

nsns2.0V ≤ VDD ≤ 3.0V

—

3.0V ≤ VDD ≤ 6.0V

DS30445C-page 80  1997 Microchip Technology Inc.

FIGURE 11-6: TIMER0 CLOCK TIMINGS

RA4/T0CKI

PIC16C84

40 41

TABLE 11-6 TIMER0 CLOCK REQUIREMENTS

Parameter

No.

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

42 Tt0P T0CKI Period TCY + 40 *N— — ns N = prescale value

* These parameters are characterized but not tested. † Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not

Sym Characteristic Min Typ† Max Units Conditions

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

With Prescaler 50 *

tested.

30 *

20 *

————nsns2.0V ≤ VDD ≤ 3.0V

3.0V ≤ VDD ≤ 6.0V

————nsns2.0V ≤ VDD ≤ 3.0V

3.0V ≤ VDD ≤ 6.0V

(2, 4, ..., 256)

 1997 Microchip Technology Inc. DS30445C-page 81

PIC16C84

NOTES:

DS30445C-page 82  1997 Microchip Technology Inc.

PIC16C84

12.0 DC & AC CHARACTERISTICS GRAPHS/TABLES FOR PIC16C84

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 (i.e., outside speciﬁed V

range). This is for information only and devices are guaranteed to 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 and matrix samples. 'Typical' represents the mean of the distribution at 25°C, while 'max' or 'min' represents (mean + 3σ) and (mean - 3σ) respectively, where σ is standard deviation.

FIGURE 12-1: TYPICAL RC OSCILLATOR FREQUENCY vs. TEMPERATURE

FOSC

FOSC (25°C)

1.10

1.08

1.06

1.04

1.02

1.00

0.98

0.96

0.94

0.92

0.90

0.88

Frequency Normalized To +25°C

Rext ≥ 10 kΩ

Cext = 100 pF

VDD = 5.5V

VDD = 3.5V

0 10 20 25 30 40 50 60 70

T(°C)

TABLE 12-1 RC OSCILLATOR FREQUENCIES *

Cext Rext

20 pF 3.3k 4.68 MHz ± 27%

5.1k 3.94 MHz ± 25% 10k 2.34 MHz ± 29%

100k 250.16 kHz ± 33%

100 pF 3.3k 1.49 MHz ± 25%

5.1k 1.12 MHz ± 25% 10k 620.31 kHz ± 30%

100k 90.25 kHz ± 26%

300 pF 3.3k 524.24 kHz ± 28%

5.1k 415.52 kHz ± 30% 10k 270.33 kHz ± 26%

100k 25.37 kHz ± 25%

*Measured in PDIP Packages.The percentage variation indicated here is part to part variation due to nor mal process distribution. The variation indicated is ±3 standard deviation from average value.

 1997 Microchip Technology Inc. DS30445C-page 83

Average

Fosc @ 5V, 25°C

PIC16C84

FIGURE 12-2: TYPICAL RC OSCILLATOR FREQUENCY vs. VDD (Cext = 20 pF)

5.5

5.0

4.5

4.0

3.5

3.0

2.5

FOSC (MHz)

2.0

1.5

1.0

0.5

0.0

2.0 2.5

Rext = 3.3k

Rext = 5k

T = 25°C

Rext = 10k

Rext = 100k

3.0 3.5 4.0 4.5 5.0 5.5 6.0 VDD (Volts)

DS30445C-page 84  1997 Microchip Technology Inc.

PIC16C84

FIGURE 12-3: TYPICAL RC OSCILLATOR FREQUENCY vs. VDD (Cext = 100 pF)

2.2

2.0

1.8 Rext = 3.3k

1.6

1.4

1.2

1.0

FOSC (MHz)

Rext = 5k

0.8

0.6

0.4

0.2

0.0

2.0 2.5

T = 25°C

3.0 3.5 4.0 4.5 5.0 5.5 6.0 VDD (Volts)

Rext = 10k

Rext = 100k

FIGURE 12-4: TYPICAL RC OSCILLATOR FREQUENCY vs. V

1.1

1.0

0.9

0.8 T = 25°C

0.7

Rext = 3.3k

0.6

DD (Cext = 300 pF)

0.5

FOSC (MHz)

0.4

0.3

0.2

0.1

0.0

2.0 2.5

 1997 Microchip Technology Inc. DS30445C-page 85

3.0 3.5 4.0 4.5 5.0 5.5 6.0 VDD (Volts)

Rext = 5k

Rext = 10k

Rext = 100k

PIC16C84

FIGURE 12-5: TYPICAL IPD vs. VDD WATCHDOG DISABLED (25˚C)

IPD (µA)

3.5 4.0 4.5 5.0 5.5

6.03.02.52.0

VDD (Volts)

FIGURE 12-6: TYPICAL IPD vs. VDD WATCHDOG ENABLED (25˚C)

IPD(µA)

3.5 4.0 4.5 5.0 5.5

6.03.02.52.0

VDD (Volts)

DS30445C-page 86  1997 Microchip Technology Inc.

FIGURE 12-7: MAXIMUM IPD vs. VDD WATCHDOG DISABLED

120

100

PIC16C84

Max. Temp. = 85°C

Typ. Temp. = 25°C

Min. Temp. = -40°C

3.5 4.0 4.5 5.0 5.5

VDD (Volts)

IPD(µA)

FIGURE 12-8: MAXIMUM IPD vs. VDD WATCHDOG ENABLED*

120

100

6.03.02.52.0

IPD(µA)

* IPD, with W atchdog Timer enab led, has two components: The leakage current which increases with higher temperature and the operating current of the Watchdog Timer logic which increases with lower temperature. At -40°C, the latter dominates explaining the apparently anomalous behavior.

Max. Temp. = 85°C

Typ. Temp. = 25°C

Min. Temp. = -40°C

3.5 4.0 4.5 5.0 5.5

VDD (Volts)

6.03.02.52.0

 1997 Microchip Technology Inc. DS30445C-page 87

PIC16C84

FIGURE 12-9: VTH (INPUT THRESHOLD VOLTAGE) OF I/O PINS vs. VDD

2.0

1.8 Max (-40°C to +85°C)

1.6

Typ @ 25°C

1.4

1.2

VTH(Volts)

1.0

0.8

0.6

2.5

3.0 3.5 4.0 4.5 5.0 5.5 6.0

VDD (Volts)

Min (-40°C to +85°C)

FIGURE 12-10: VTH (INPUT THRESHOLD VOLTAGE) OF OSC1 INPUT (IN XT, HS, AND LP MODES)

vs. VDD

3.4

3.2

3.0

2.8

2.6

VTH (Volts)

2.4

2.2

Max (-40°C to +85°C)

Typ (25°C)

2.0

1.8

1.6

1.4

1.2

1.0

2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (Volts)

DS30445C-page 88  1997 Microchip Technology Inc.

Min (-40°C to +85°C)

6.0

FIGURE 12-11: VIH, VIL OF MCLR, T0CKI and OSC1 (IN RC MODE) vs. VDD

PIC16C84

VIH, VIL(volts)

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

2.0

VIH, max (-40°C to +85°C)

VIH, typ (25°C)

VIH, min (-40°C to +85°C)

VIL, max (-40°C to +85°C)

VIL, typ (25°C)

VIL, min (-40°C to +85°C)

2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (Volts)

6.0

 1997 Microchip Technology Inc. DS30445C-page 89

PIC16C84

FIGURE 12-12: TYPICAL IDD vs. FREQ (EXT CLOCK, 25˚C)

10,000

1,000

IDD (µA)

6.0V

100

5.5V

5.0V

4.5V

4.0V

3.5V

3.0V

2.5V

2.0V

10k 100k 1M 10M 100M

External Clock Frequency (Hz)

FIGURE 12-13: MAXIMUM IDD vs. FREQ (EXT CLOCK, -40˚ TO +85˚C)

10,000

1,000

6.0V

5.5V

IDD (µA)

5.0V

4.5V

4.0V

100

3.5V

3.0V

2.5V

2.0V

10k 100k 1M 10M 100M

External Clock Frequency (Hz)

DS30445C-page 90  1997 Microchip Technology Inc.

FIGURE 12-14: WDT TIME-OUT PERIOD vs. VDD

Max. 85°C

Max. 70°C

Typ. 25°C

WDT Time-out Period (ms)

Min. -40°C

Min. 0°C

PIC16C84

2.5 3.5 4.0 4.5 5.0

3.02.0

DD (Volts)

FIGURE 12-15: TRANSCONDUCTANCE (gm) OF HS OSCILLATOR vs. VDD

10000

9000 8000 7000

6000

gm(µA/V)

5000 4000 3000

2000

Max @ -40°C

5.5 6.0

Typ @ 25°C

Min @ 85°C

1000

2.0 3.5 3.0 3.5 4.0 4.5

VDD (Volts)

 1997 Microchip Technology Inc. DS30445C-page 91

5.0 5.5

PIC16C84

FIGURE 12-16: TRANSCONDUCTANCE (gm) OF LP OSCILLATOR vs. VDD

250 225 200

gm(µA/V)

175 150 125 100

75 50

2.0 2.5 3.0 3.5 4.0 4.5

Max @ -40°C

VDD (Volts)

FIGURE 12-17: TRANSCONDUCTANCE (gm) OF XT OSCILLATOR vs. VDD

2000 1800 1600 1400 1200

Max @ -40°C

Typ @ 25°C

Min @ 85°C

5.0 5.5

Typ @ 25°C

1000

800

gm(µA/V)

600 400

200

2.0 2.5 3.0 3.5 4.0 4.5

VDD (Volts)

DS30445C-page 92  1997 Microchip Technology Inc.

Min @ 85°C

5.0 5.5

FIGURE 12-18: IOH vs. VOH, VDD = 3V

-2

-4

-6 Min @ 85°C

IOH (mA)

-8

-10

PIC16C84

-12

-14

-16

-18

0.0 0.5 1.0 1.5 2.0 2.5

Max @ -40°C

Typ @ 25°C

FIGURE 12-19: IOH vs. VOH, VDD = 5V

-5

-10

-15

-20

-25

-30

IOH (mA)

-35

Typ @ 25°C

3.0

VOH (Volts)

Min @ 85°C

Max @ -40°C

-40

-45

0.0 0.5 1.0 1.5 2.0 2.5

VOH (Volts)

 1997 Microchip Technology Inc. DS30445C-page 93

3.0

3.5 4.0 4.5 5.0

PIC16C84

FIGURE 12-20: IOL vs. VOL, VDD = 3V

IOL (mA)

Max. -40°C

Typ. 25°C

Min. +85°C

0.0 0.5 1.0 1.5 2.0

FIGURE 12-21: IOL vs. VOL, VDD = 5V

90 80 70

60 50

IOL (mA)

40 30

20 10

0.0 0.5 1.0 1.5 2.0 2.5

OL (Volts)

Max @ -40°C

2.5 3.0

Typ @ 25°C

Min @ +85°C

3.0

VOL (Volts)

DS30445C-page 94  1997 Microchip Technology Inc.

PIC16C84

FIGURE 12-22: MAXIMUM DATA MEMORY ERASE/WRITE CYCLE TIME VS. VDD

DMEM Max. E/W Cycle Time (ms)

2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

VDD (Volts)

Shaded areas are beyond recommended range.

TABLE 12-2 INPUT CAPACITANCE*

Pin Name

18L PDIP 18L SOIC

PORTA 5.0 4.3 PORTB 5.0 4.3

MCLR

17.0 17.0 OSC1/CLKIN 4.0 3.5 OSC2/CLKOUT 4.3 3.5 T0CKI 3.2 2.8

* All capacitance values are typical at 25°C. A part to part variation of ±25% (three standard deviations) should

be taken into account.

Typical Capacitance (pF)

6.51.5 2.0

 1997 Microchip Technology Inc. DS30445C-page 95

PIC16C84

NOTES:

DS30445C-page 96  1997 Microchip Technology Inc.

13.0 PACKAGING INFORMATION

13.1 K04-007 18-Lead Plastic Dual In-line (P) – 300 mil

PIC16C84

Units INCHES* MILLIMETERS Dimension Limits MIN NOM MAX MIN NOM MAX PCB Row Spacing 0.300 7.62 Number of Pins n 18 18 Pitch p 0.100 2.54 Lower Lead Width B 0.013 0.018 0.023 0.33 0.46 0.58 Upper Lead Width Shoulder Radius R 0.000 0.005 0.010 0.00 0.13 0.25 Lead Thickness c 0.005 0.010 0.015 0.13 0.25 0.38 Top to Seating Plane A 0.110 0.155 0.155 2.79 3.94 3.94 Top of Lead to Seating Plane A1 0.075 0.095 0.115 1.91 2.41 2.92 Base to Seating Plane A2 0.000 0.020 0.020 0.00 0.51 0.51 Tip to Seating Plane L 0.125 0.130 0.135 3.18 3.30 3.43 Package Length Molded Package Width Radius to Radius Width E1 0.230 0.250 0.270 5.84 6.35 6.86 Overall Row Spacing eB 0.310 0.349 0.387 7.87 8.85 9.83 Mold Draft Angle Top Mold Draft Angle Bottom

* Controlling Parameter.

†

Dimension “B1” does not include dam-bar protrusions. Dam-bar protrusions shall not exceed

0.003” (0.076 mm) per side or 0.006” (0.152 mm) more than dimension “B1.”

‡

Dimensions “D” and “E” do not include mold ﬂash or protrusions. Mold ﬂash or protrusions shall not exceed 0.010” (0.254 mm) per side or 0.020” (0.508 mm) more than dimensions “D” or “E.”

D E

α β

†

‡ ‡

0.055 0.060 0.065 1.40 1.52 1.65

0.890 0.895 0.900 22.61 22.73 22.86

0.245 0.255 0.265 6.22 6.48 6.73

5 10 15 5 10 15 5 10 15 5 10 15

 1997 Microchip Technology Inc. DS30445C-page 97

PIC16C84

13.2 K04-051 18-Lead Plastic Small Outline (SO) – Wide, 300 mil

2 1

Units Dimension Limits Pitch

Overall Pack. Height Shoulder Height Standoff Molded Package Length Molded Package Width Outside Dimension Chamfer Distance Shoulder Radius Gull Wing Radius Foot Length Foot Angle Radius Centerline Lead Thickness Lower Lead Width Mold Draft Angle Top Mold Draft Angle Bottom

Controlling Parameter.

†

Dimension “B” does not include dam-bar protrusions. Dam-bar protrusions shall not exceed 0.003”

(0.076 mm) per side or 0.006” (0.152 mm) more than dimension “B.”

‡

p nNumber of Pins A A1 A2 D E E1 X R1 R2 L

L1 c B

α β

INCHES*

MIN

0.093

0.048

‡

†

0.004

0.450

0.292

0.394

0.010

0.005

0.011 0

0.010

0.009

0.014 0 0

NOM MAX

0.050

0.099

0.058

0.008

0.456

0.296

0.407

0.020

0.005

0.016

0.015

0.011

0.017

0.104

0.068

0.011

0.462

0.299

0.419

0.029

0.010

0.021

0.020

0.012

0.019 12 12

MILLIMETERS

MIN NOM MAX

2.36

1.22

0.10

11.43

7.42

10.01

0.25

0.13

0.28

15 15

0.25

0.23

0.36 0 0

1.27 1818

2.50

1.47

0.19

11.58

7.51

10.33

0.50

0.13

0.41

4 8

0.38

0.27

0.42 12 12

2.64

1.73

0.28

11.73

7.59

10.64

0.74

0.25

0.53

0.51

0.30

0.48 15 15

DS30445C-page 98  1997 Microchip Technology Inc.

PIC16C84

APPENDIX A: FEATURE

IMPROVEMENTS FROM PIC16C5X TO PIC16C84

The following is the list of feature improvements over the PIC16C5X microcontroller family:

1. Instruction word length is increased to 14 bits. This allows larger page sizes both in program memory (2K now as opposed to 512 before) and the register ﬁle (128 bytes now versus 32 bytes before).

2. A PC latch register (PCLATH) is added to handle program memory paging. PA2, PA1 and P A0 bits are removed from the status register and placed in the option register.

3. Data memor y paging is redeﬁned slightly. The STATUS register is modiﬁed.

4. Four new instructions have been added: RETURN, RETFIE, ADDLW, and SUBLW. Two instructions, TRIS and OPTION, are being phased out although they are kept for compatibility with PIC16C5X.

5. OPTION and TRIS registers are made addressable.

6. Interrupt capability is added. Interrupt vector is at 0004h.

7. Stack size is increased to 8 deep.

8. Reset vector is changed to 0000h.

9. Reset of all registers is revisited. Five different reset (and wake-up) types are recognized. Registers are reset differently.

10. Wake up from SLEEP through interrupt is added.

11. Two separate timers, the Oscillator Start-up Timer (OST) and Power-up Timer (PWRT), are included for more reliable power-up. These timers are invoked selectively to avoid unnecessary delays on power-up and wake-up.

12. PORTB has weak pull-ups and interrupt on change features.

13. T0CKI pin is also a port pin (RA4/T0CKI).

14. FSR is a full 8-bit register.

15. "In system programming" is made possible. The user can program PIC16CXX devices using only ﬁve pins: V (data in/out).

DD, VSS, VPP, RB6 (clock) and RB7

APPENDIX B: CODE COMPATIBILITY

- FROM PIC16C5X TO PIC16C84

To convert code written for PIC16C5X to PIC16C84, the user should take the following steps:

1. Remove any program memory page select operations (PA2, PA1, PA0 bits) for CALL, GOTO .

2. Revisit any computed jump operations (write to PC or add to PC, etc.) to make sure page bits are set properly under the new scheme.

3. Eliminate any data memory page switching. Redeﬁne data variables for reallocation.

4. Verify all writes to STATUS, OPTION, and FSR registers since these have changed.

5. Change reset vector to 0000h.

 1997 Microchip Technology Inc. DS30445C-page 99

PIC16C84

APPENDIX C: WHAT’S NEW IN THIS

DATA SHEET

No new information has been added to this data sheet. For information on upgrade devices from the

PIC16C84, please refer to the PIC16F8X data sheet.

APPENDIX D: WHAT’S CHANGED IN

THIS DATA SHEET

Here’s what’s changed in this data sheet:

1. Some sections have been rearranged for clarity and consistency.

2. Errata information has been included.

DS30445C-page 100  1997 Microchip Technology Inc.

MICROCHIP PIC16C84 Technical data

Specifications and Main Features

Frequently Asked Questions

User Manual

1.0 GENERAL DESCRIPTION

2.0 PIC16C84 DEVICE VARIETIES

3.0 ARCHITECTURAL OVERVIEW

3.1 Clocking Scheme/Instruction Cycle

3.2 Instruction Flow/Pipelining

4.0 MEMORY ORGANIZATION

4.2 Data Memory Organization

4.2.1 GENERAL PURPOSE REGISTER FILE All devices have some amount of General Purpose

4.2.2 SPECIAL FUNCTION REGISTERS The Special Function Registers (Figure 4-2 and

4.3 Program Counter: PCL and PCLATH

4.3.1 COMPUTED GOTO A computed GOT O is accomplished b y adding an offset

4.4 Stack

4.3.2 PROGRAM MEMORY PAGING The PIC16C84 has 1K of program memory. The CALL

5.0 I/O PORTS

5.1 PORTA and TRISA Registers

5.2 PORTB and TRISB Registers

5.3 I/O Programming Considerations

5.3.1 BI-DIRECTIONAL I/O PORTS Any instruction which writes, operates internally as a

5.3.2 SUCCESSIVE OPERATIONS ON I/O PORTS The actual write to an I/O port happens at the end of an

6.1 TMR0 Interrupt

6.2 Using TMR0 with External Clock

6.2.1 EXTERNAL CLOCK SYNCHRONIZATION

6.2.2 TMR0 INCREMENT DELAY Since the prescaler output is synchronized with the

6.3 Prescaler

6.3.1 SWITCHING PRESCALER ASSIGNMENT

7.0 DATA EEPROM MEMORY

7.1 EEADR

7.2 EECON1 and EECON2 Registers

7.3 Reading the EEPROM Data Memory

7.4 Writing to the EEPROM Data Memory

7.5 Write Verify

7.6 Protection Against Spurious Writes

7.8 Power Consumption Considerations

8.2.1 OSCILLATOR TYPES The PIC16C84 can be operated in four different

8.2.4 RC OSCILLATOR For timing insensitive applications the RC de vice option

8.3 Reset

8.4 Power-on Reset (POR)

8.5 Power-up Timer (PWRT)

8.6 Oscillator Start-up Timer (OST)

8.8 Reset on Brown-Out

8.9 Interrupts

8.9.1 INT INTERRUPT External interrupt on RB0/INT pin is edge triggered:

8.9.2 TMR0 INTERRUPT An overﬂow (FFh → 00h) in TMR0 will set ﬂag bit T0IF

8.9.3 PORT RB INTERRUPT An input change on PORTB<7:4> sets ﬂag bit RBIF

8.10 Context Saving During Interrupts

8.11 Watchdog Timer (WDT)

8.11.1 WDT PERIOD The WDT has a nominal time-out period of 18 ms, (with

8.11.2 WDT PROGRAMMING CONSIDERATIONS It should also be taken into account that under worst

8.12 Power-down Mode (SLEEP)

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

SLEEP

8.12.3 WAKE-UP USING INTERRUPTS When global interrupts are disabled (GIE cleared) and

8.14 ID Locations

8.15 In-Circuit Serial Programming

9.0 INSTRUCTION SET SUMMARY

9.1 Instruction Descriptions

10.0 DEVELOPMENT SUPPORT

10.1 Development Tools

10.4 PRO MATE II: Universal Programmer

10.10 Assembler (MPASM)

10.11 Software Simulator (MPLAB-SIM)

10.12 C Compiler (MPLAB-C)

11.0 ELECTRICAL CHARACTERISTICS FOR PIC16C84

13.0 PACKAGING INFORMATION

APPENDIX B: CODE COMPATIBILITY