Scott,

The problem here is that every time you 'RRF PORTA', the entire port it
read, and the first bit is rotated into the C bit.  Rather than rotating the
port each time, you need to read the port into memory first, then rotate
that data.  Example: (sorry for the mixed Parallax & Microchip mnemonics)

    movw  porta
    movf   myvar, w
    rrf       myvar
    btfsc   status, c
    goto    code1
    rrf       myvar
    btfsc   status, c
    goto    code2
    .
    .
    .

Only problem this creates is that any changes in portA during processing are
not recognized until next time through this code.

Mitch Miller
Omaha, NE
mdmiller2@home.com



----- Original Message -----
From: Scott <spamdogg@webbernet.net>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Tuesday, October 19, 1999 8:02 PM
Subject: Polling PortA


> I want to use portA to read two switches for one project and four
> switches for another.  How do I make each bit rotate through the carry
> flag consecutivly.  I have been using the following code, but it only
> reads the first bit. I am using a 16c56
>
>
>              movlw         0x0F
>              tris              PORTA
>              movlw         0x00
>              tris              PORTB
>
> input      bcf              STATUS, C
>              rrf               PORTA, W
>              btfsc            STATUS, C
>              goto             code_1
>              rrf               PORTA, W
>              btfsc            STATUS, C
>              goto             code_2
>              goto             input
>
> I was able to write the rest of this program and simulate it with
> success and I have been stareing at this part for four hours with no
> luck.
>
> Scott