A project of mine is almost finished. The final(?) problem seems to be
I cannot get the interrupt working properly. Consider this (extracted)
code:


init
        banksel INTCON                          ; Clear all but Timer1
interrupt-masks
        clrf    INTCON
        clrf    PIE1
        clrf    PIE2
        bsf     PIE1, TMR1IE
        bsf     INTCON, GIE                     ; Enable global interrupts

        banksel T1CON                           ; Setup Timer1
        bsf     T1CON, T1OSCEN                  ; Enable internal oscillator
        bsf     T1CON, TMR1CS                   ; Use external clock
(built-in 32kHz)

        call delay_5_secs

        bsf     T1CON, TMR1ON                   ; Start timer1-oscillator

mainloop:
      goto mainloop                               ; Just for the sake of nothing

isr_code
        bsf     TMR1H, 7                        ; set TMR1H to 0x80

        context_save                            ; save variables/status etc

        bcf     INTCON, INTF                    ; Clear hardware interrupt flag

        btfsc   PIR1, TMR1IF                    ; Did Timer1 overflow?
         call   once_a_sec                      ; Yes, do our timer-stuff

        context_restore                      ; restore variables
        retfie

once_a_sec
       bcf     PIR1, TMR1IF                    ; Reset interrupt flag
       bcf     PORTA, 4                         ; turn off the red LED
       bsf     PORTA, 5                         ; turn on the green led
       return


Expected behaviour: After the PIC is switched on and after a delay of
5 secs (it's there to ensure proper oscillator-startups), the red led
should be turned off and the green turned on.

What's happening: The red LED keeps on being lit, which means that
I've either done the init wrong and the ISR is never called, or the
ISR is wrong.

I am using the internal 32kHz-oscillator in the 16F886-chip. Or,
that's atleast what I want to.

Are there any obvious errors I've done?


-- 
- Rikard - http://bos.hack.org/cv/
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