PICers - here's something that really had me stumped for a couple of days.
I wrote code to operate a camera. It configs the OPTION_REG and the INTCON as
shown, then waraps up housekeeping functions and goes to sleep to wait for an
interrupt on RB0 or RB6/RB7 keychange as case may be.

What nearly drove me nuts was the hardware kept self interrupting all the time,
yet the simulator (MPLAB) behaved normally.  ie It went to sleep, stayed
asleep. The protoboard hardware version (4MHz) would get to the sleep instruc
then jump to the ISR. Even if I left GIE cleared. 
I "cured" (?) it by changing the OPTION_REG from b'10000111' to b'00001000'

What I can't figure out is why? When you disable the INTCON (GIE=0), then it
shouldn't make any difference what you have in OPTION_REG? 

Any ideas what's going on? ie are there any restrictions on what you can out
into the option register v/v interrupts?

Debbie

setint:
        BANK_1
        movlw    b'00001000'     ;Original config = '10000111'
                                 ;b7 - RBPU' = 1 => Pull-ups disabled,
                                 ;b6 - INTEDG = 1 => RB0 int. on rising 
                                 ;b5 - TOCS = TMR0 Clock Slct. 
                                 ;b4 - TOSE => Clock edge select
                                 ;b3 - PSA = 1 =>  Prescaler assigned to WDT, 
                                 ;           0 => Prescaler assigned to TMR0
                                 ;b2, b1, b0 : Prescaler Rate Select          
        movwf    OPTION_REG
        BANK_0
        PAGE_0
        movlw    b'00011000'     ;Disable interrupts for now. GIE=0
                                 ;b7 - GIE=0 temporarily
                                 ;b6 - Disable EE write
                                 ;b5 - Disable TMR0 interrupt
                                 ;b4 - Enable RB0 interrupt
                                 ;b3 - Ensable Interrupt on change RB4-7
                                 ;b2 - Clear TMR0 flag = no overflow
                                 ;b1 - Clear RB0 int. flag
                                 ;b0 - Clear RB port Change Int. flag    
        movwf    INTCON        

<..snip..>

call    power_off
        bcf     STATUS_LED
        clrf    flags
        movlw   b'10011000'     ;Now enable the interrupts
        movwf   INTCON
        nop
        sleep                   ;Shut down and wait for an interrupt
        nop
<..snip..>


		
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