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Contents

Contents at a Glance

Contents

List of Programs

Introduction

• Background

  What you need

  What you should know

Introducing the PIC’84

• Architecture

  Instruction Set

  A simple PIC’84 program

  Using MPLAB to debug the program

  Pause to reflect

The Instruction Set

• Instruction format

  The STATUS register

  1: Move instructions

  • MOVF f,d (Move f, PIC p58)

    MOVWF f (Move W to f, PIC p58)

    MOVLW k (Move literal to W, PIC p58)

  2: Clear instructions

  • CLRF f (Clear f, PIC p55)

    CLRW (Clear W, PIC p55)

  3: Arithmetic instructions

  • ADDWF f,d (Add W & f, PIC p53)

    SUBWF f,d (Subtract W from f, PIC p61)

    ADDLW k (Add literal & W, PIC p53)

    SUBLW k (Subtract W from literal, PIC p61)

  4: Logical functions

  • ANDWF f,d (AND W with f, PIC p53)

    IORWF f,d (Inclusive OR W with f, PIC p58)

    XORWF f,d (Exclusive OR W with f, PIC p62)

    ANDLW k (AND literal with W, PIC p53)

    IORLW k (Inclusive OR literal with W, PIC p57)

    XORLW k (Exclusive OR literal with W, PIC p62)

    COMF f,d (Complement f, PIC p56)

  5: Decrementing & Incrementing

  • DEC f,d (Decrement f, PIC p56)

    INC f,d (Increment f, PIC 57)

  6: Bit setting & clearing

  • BCF f,b (Bit clear f, PIC p54)

    BSF f,b (Bit set f, PIC p54)

  7: Program control

  • GOTO k (Go to address, PIC p57)

    CALL k (Call subroutine, PIC p55)

    RETURN (Return from subroutine, PIC p60)

    RETLW k (Return with literal in W, PIC p59)

    RETFIE (Return from Interrupt, PIC p59)

  8: Skipping instructions

  • DECFSZ f,d (Decrement f, skip if 0, PIC p56)

    INCFSZ f,d (Increment f, skip if 0, PIC p57)

    BTFSC f,b (Bit test f, skip if clear, PIC p54)

    BTFSS f,b (Bit test f, skip if set, PIC p55)

  9: Rotations & Swap

  • RRF f,d (Rotate right f thru carry, PIC p60)

    RLF f,d (Rotate left f thru carry, PIC p60)

    SWAPF f,d (Swap nybbles in f, PIC p62)

  10: Sleep & Watchdog Timer

  • SLEEP (Sleep, PIC p60)

    CLRWDT (Clear watchdog timer, PIC p56)

  11: Miscellaneous

  • NOP (No operation, PIC p59)

    OPTION (Not recommended)

    TRIS (Not recommended)

  Pause to reflect

Interrupts on the ’84

• What’s an interrupt?

  Types of Interrupt and the INTCON register

  Servicing an Interrupt

Timers on the ’84

• The basic idea

  The TIMER0 module

  Using the timer’s overflow

Using the EEPROM data memory

Appendix: Program listings

List of Programs

Program 1: simple . asm

• • Program 2: moves . asm

    Program 3: clears . asm

    Program 4: arith . asm

    Program 5: inter1.asm

    Program 6: inter2.asm

    Program 7: inter3.asm

    Program 8: time0.asm

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