Hi, I am still trying this one (seems it was not posted):

This is probably a newbie question.  I am trying to get to know PICs by playing with the 12C671 using the MPLAB simulator.  I can successfully toggle PORTS 0, 1 and 2, but 4 and 5 still seem stuck (their bits in GPIO do not move).
This is my simple code:

        list      p=12c671            ; list directive to define processor
        #include <p12c671.inc>        ; processor specific variable definitions
        errorlevel  -302              ; suppress message 302 from list file
        __CONFIG   _CP_OFF & _WDT_OFF & _MCLRE_OFF & _PWRTE_OFF & INTRC_OSC_NOCLKOUT ;
                ORG     0x000             ; processor reset vector
                bsf     STATUS,RP0        ; set file register bank to 1 
              movlw   b'11001000'       ; Internal clk,prescaler to wdt
              movwf   OPTION_REG        ;
              movlw   b'00000000'       ;
              movwf   TRISIO            ; all ports but 3 are outputs
              movlw     7                 ;
                 movwf  ADCON1            ; All Ports digital
                 bcf     STATUS,RP0        ; set file register bank to 0
loop
                bsf     GPIO,4            ;
                bcf     GPIO,4            ; toggle gp4
                goto    loop              ;
                end                       ; directive 'end of program' 

I cannot find anything in the datasheet to show up the problem.  Does anybody know if this could be a MPLAB bug?

Stefan Rousseau
stefanr@rrs.co.za
Technopark
Stellenbosch
South Africa