Stefan,

If I'm not mistaken, the '671 is *not* a 12 bit, but rather a 14 bit
core device.  Therefore, try manipulating the GPIO's actual TRIS
register, instead of trying to use the 'TRIS' instruction.  See if that
doesn't help.

Good Luck,

Chuck Mauro

> -----Original Message-----
> From: Stefan Rousseau [SMTP:stefanr@RRS.CO.ZA]
> Sent: Wednesday, May 06, 1998 7:45 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: PIC 12C671 GPIO control
>
> Hi
>
> This did not solve my GPIO problem.  Does anybody else have any
> advice?
> I am trying a simple application for a 12C671 using MPLAB 3.40.
> Trouble is I cannot seem to get the I/O's to toggle under the
> simulator (no change in the gpio SFR) by
>
> #define         DOUT    GPIO,2  ; SPI port DOUT signal
> ...
>                 bsf     STATUS,RP0        ; set file register bank to
> 1
>                 movwf   OSCCAL            ; update register with
> factory cal value
> movlw   b'11001000'        ;Internal clk,prescaler to wdt
>              movwf   OPTION_REG   ;
>              movlw   b'00001001'        ;
>              movwf   TRISIO               ; port 0, 3 are inputs, rest
> outputs
>
>                 bcf     STATUS,RP0        ; set file register bank to
> 0
>                 bsf     DOUT;
>               bcf     DOUT;
> ...
>
> Could somebody please point out my error to me?
>
> Stefan Rousseau
> stefanr@rrs.co.za
> Technopark
> Stellenbosch
> South Africa
>
>
>
> ----------
> From:  Kalle Pihlajasaari[SMTP:kalle@DEVICE.DATA.CO.ZA]
> Sent:  Wednesday, May 06, 1998 12:29 PM
> Subject:  Re: PIC 12C671 GPIO control
>
> Hi Stefan,
>
> > I am new to PICs so please excuse any blatant ignorance....  I am
> trying =
> > a simple application for a 12C671 using MPLAB 3.40.  Trouble is I
> cannot =
> > seem to get the I/O's to toggle under the simulator (no change in
> the =
> > gpio SFR) by=20
>
> Not sure what the simulator should be doing here but the hardware will
> not work as you have programmed it.
>
> >              movlw   b'00001001'        ;
> >              movwf   TRISIO               ; port 0, 3 are inputs,
> rest =
> > outputs
>
> The 12C671 is almost certainly a 12bit core like the 12C508/9 which I
> have
> used.  They do not use the TRISIO register as a regular register.
>
> You have to use the TRIS instruction.  Best you examine the short
> one page opcode listing to check which special opcodes are supported
> when changing between 12, 14 or 16 bit programming.
>
> Cheers