16F1827 ASM Interrupt

[abbtech]

Thanks Darrel that clears up why things were not working as I expected!

Most things are working great now except one very strange thing. The LED that is to be used to indicate this interrupt state (on RB0) works fine when RB3 has initiated the interrupt however when RB2 has initiated the interrupt when I attempt to flash RB0 it somehow turns off RB2 which is the pin that was changed from an input to an output and made high.

In the code shown below I am using the wrong LED (RA6) to indicate the RB2 interrupt condition and everything works fine other than the wrong LED flashing.

I am thinking that there is some strange property that RB0 has but I am very confused why it doesn't mess up when RB3 has initiated the interrupt.

;the following is the interrupt routine 
ASM 
intRoutine

    ;turn off interrupts
    MOVLW   b'00000000'
    MOVWF   INTCON
    
    ;disable all interrupts that were previously enabled
    MOVLB   0x07    ;select BANK 7
    MOVLW   b'00000000'
    MOVWF   IOCBP
    
    ;RB3 is currently an input, change it to an output and make it high
    ;prior to this operation TRISB would be 11111110
    MOVLB   0x01    ;select BANK 1
    MOVLW   b'11110110'
    MOVWF   TRISB

    ;turn on RB3  (doesn't go high)
    MOVLB   0x00    ;select BANK 0
    BSF PORTB,3

    ;turn off detection power (this is working fine)
    BCF PORTA,0
        
    ;check to see what tripped the interrupt 
    ;IOCBF.2 = detection 
    ;IOCBF.3 = lighting 
    MOVLB   0x07    ;select BANK 7
    BTFSS   IOCBF,3
    GOTO    detectionFlash
    GOTO    lightingFlash

lightingFlash
    MOVLB   0x00    ;select BANK 0
    BSF    PORTB,0
    CALL    Delay
    BCF    PORTB,0
    CALL    Delay
    CALL    Delay
    GOTO    lightingFlash
    
detectionFlash
    MOVLB   0x00    ;select BANK 0
    BSF    PORTA,6 ;this is the wrong LED but works properly when this one is selected instead of PORTB,0
    CALL    Delay
    BCF    PORTA,6
    CALL    Delay
    BSF    PORTA,6
    CALL    Delay
    BCF    PORTA,6
    CALL    Delay
    CALL    Delay
    GOTO    detectionFlash   

endASM

[abbtech]

Thanks for the code example cncmachineguy.

I have it working properly now. I am thinking there must be some type of race condition with the way I had it coded. I have added a delay right after B3 was made high and everything works fine. Without the delay B3 goes low as soon as B0 is made high.

Thanks for the help guys!