Long time ago some one in this list used to have this problem using 508 instead
of 671.

I spent lots of time on that and  found  this.
when you use 12cxxx  internal clock enabled  Mplab doesn't recognize that
it things that you are using external witch is not what you need.
I do not know if it is bug or not what I think it should see it.

**solution**

in mplab open options / processor setup / hardware then change external to inter
nal.

if it did not work let me know .

Andre Abelian


Dave Mumert wrote:

> Hi all
>
> Can someone explain why the following code does not change GP4 and GP5 in
> the MPLAB SIM?
> I think I may be losing my mind.
>
>         list      p=12c671            ; list directive to define processor
>         #include <p12c671.inc>        ; processor specific variable definition
s
>
>         __CONFIG   _CP_OFF & _WDT_ON & _PWRTE_ON & _INTRC_OSC_NOCLKOUT & _MCLR
E_OFF
>
>         org     0
> main
>         bsf   STATUS,RP0      ; set file register bank to 1
>         clrf    INTCON          ; disable all interupts
>         clrf    PIE1            ; disable peripheral interupts
>         movlw   04H             ;was 04
>         movwf   ADCON1          ; set GP0,GP1 to analog inputs
>         movlw   B'00001011'
>         movwf   GPIO            ; set bit 0, 1, 3 to inputs
>         movlw   B'10001111'
>         movwf   OPTION_REG      ; set Option register
>         btfss   PCON,1          ; have we just powered up
>         bcf   STATUS,RP0      ; set file register bank to 0
> ;
> Main1
>         movlw   00H
>         movwf   GPIO
>         movlw   034H
>         movwf   GPIO
>         goto    Main1
>
>         end
>
> Thanks
>
> Dave Mumert
> dmumert@telusplanet.net