At 09:47 25/05/98 +0100, you wrote:
>Aaron,
>
>If you get any feedback on this I'd appreciate it if you could pass it on
>to me. I looked at doing this a few years ago, but felt that a uP would not
>be fast enough to do the bus stuff and all the other things I needed to do.
>Maybe I was wrong,and someone on the list knows better. Nec do a gpib chip
>set as do Texas instruments (search their website I don't have the details
>here) For my project we finally used a GPIB to RS232 converter, as it
>turned out that only very few customers needed GPIB.

Hmm, I used a Z80 to perform an entirely software implementation of GPIB.
The whole point of GPIB is that it can be made to run at the speed of the
addressed device suing the handshake lines.

I see no speed problems with inherently using a PIC, unless you want to
perform very fast data transfer.

The speed of the classic GPIB is 1MHz max, so a 4MHz 16C74A with a cycle
time of 1us couldn't quite support the maximum rate in software, but with
double or treble that clock speed you could perform transfers at the
maximum speed of the bus.

You'll need enough I/O pins or use external latches (which would slow
transfers down of course).


Regards

Adrian

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