Propix - PIC macros

Macros for Microchip PIC controllers

Most errors in programs written in assembly language are the result of the mistyped labels and conditionals. In any programming languages the use of labels reduces readability. In high level languages the use of labels are considered a bad practice and in most cases it should be avoided. I had a teacher in the university who went so far as to remove the goto instruction from the Pascal compiler we used.

Using our struct.inc macro file assembler programs are made more readable. Files can be compiled with any version of MPASM.

           movlf 20H,fsr
           loop
             clrf indf             ; Clear bank0
             incf fsr,f
           endloop_b fsr,7

Example of clearing bank 0 memory on PIC16F870

; Oscillator frequency
xtal   equ 18432000; Hz
xtime  equ 400000000/(xtal/10) ; ns

; Variables ; 20-7F
cblock 020H
  w0, w1, w2 ; Temporary registers
endc

;--------------
; Wait w*100us
; IN: w
; Registers: -
wait100us
          movwf w1
          loop
            movlf (100000/4/xtime)+1,w0 ; 100 us
            loop
              crwdt
            endloop w0
          endloop w1
          ret

Example of waiting w*100us on a processor running at 18.432 MHz

; Hardware definitions
#define ena portb,0 ; Enable input
#define inp portb,1 ; Data input
#define out portb,2 ; Output

;------------------------------------------------
; Generate pulse width modulated output if ena=1
; Assume ena and inp inputs and out is output
; Registers: -
pwm
          loop
            if_b ena
              if_b inp
                nop
                bsf out
                bcf out
              melse
                bsf out
                nop2
                bcf out
              mendif
            mendif
          endloop_infinite

Example of bit manipulation

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