16F872 and interrupt handling

[Darrel Taylor]

Hi Robson,

This might fill in a few of the blanks...

ADCON1 = %111
DEFINE OSC 4

LED1     VAR PORTB.0
LED2     VAR PORTB.1
RBCpins  VAR BYTE
LastPins VAR BYTE

TRISA = %00110000
TRISB = %11000000 ' RB7 & RB6 as inputs
TRISC = %00000000


OPTION_REG.7 = 0       ; If you want Internal PORTB Pull-ups
PAUSE 10               ; Let weak pull-ups stabilize
LastPins = PORTB       ; save current pin state, 
                       ; and end any mismatch conditions

INTCON.0 = 0           ; Clear RB Port change Int Flag
INTCON.3 = 1           ; Enable RB Port Change Interrupts
                   
ON INTERRUPT GOTO myint

main:
'...
'...
GOTO main

DISABLE
myint:
    RBCpins = PORTB                  ; read PORTB and end the mismatch
    INTCON.0 = 0                     ;  reset RB Port change INT flag
    if RBCpins.7 != LastPins.7 then  ; Pin 7 changed
        LastPins.7 = RBCpins.7
        Toggle LED1
    endif
    
    if RBCpins.6 != LastPins.6 then  ; Pin 6 changed
        LastPins.6 = RBCpins.6
        Toggle LED2
    endif
RESUME
ENABLE