I had an A/D conversion routine for an F876 that was working when I just
polled the go/!done bit.  Then I was reading the midrange manual at it said
I may have less noise if I put the PIC to sleep while the conversion was
taking place.  I changed the routine to do that by putting the PIC to
sleep, enabling the ADC interrupt, and changing the A/D clock to RC, but
the PIC never wakes up until the WDT times out.

The A/D interrupt never happens.  What am I doing wrong?  Do I really get
that much less noise?  Should I just go back to polling?


Get_ADC_Result

        bsf     PIE1, ADIE              ;enable A/D inturrupt
        bsf     INTCON, GIE     ;

DELAY   MOVLW   D'22'           ; 68 cycle delay (20 uS A/D acquistion time)
        MOVWF   COUNTER
        DECFSZ  COUNTER,F
        GOTO    $-1

        bcf     PIR1, ADIF                      ;clear A/D interrupt
        bsf     ADCON0,GO       ;Start A/D conversion
        sleep                                   ; go to sleep to perform AD conversion;



    movf    ADRESH, W  ;save ADC result
        mowf    ADRES

    return