>On Mon, 24 Jun 2002 20:36:16 -0500, Nick Veys wrote:
>>>Nick Veys wrote:
>>This would work only I need individual control of each line. I've used
>>BSF/BCF operations to do bit-banged SPI on a 16F84 before, and
>>that
>>worked just fine, it's hard to believe that I can't simply
>>toggle some
>>lines using those commands!
>
>The difference is that you were probably driving logic inputs
>when you bit banged that serial interface -- a very light load
>-- and the LED's load down the output pin because of the much
>heavier output current. Big difference there!
>
>>Should I use some kind of shadow register, set the bit in there and
>>then move it to PORTA?  Sounds extremely backwards and kludgy.
>
>Actually, it's the PIC's output port structure that's
>backwards and kludgy. ;-)
>
>Actually, it's a 6:1, half dozen the other scenario. There are
>times when being able to read the actual port pin level vs.
>the output register logic level can come in handy. You just
>have to always be aware you are reading the output PIN level,
>not the output register logic level.
>
>Matt Pobursky
>Maximum Performance Systems
>
>P.S. More people have been skewered by this pitfall than
>probably any other in the PIC world. Myself included...

Ok, everything everyone has said is starting to make sense, and you're
right, I was driving logic inputs...  Thanks everyone for the help, no I
just gotta wrap my mind around a good solution to this! :)  Thanks.

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