Andy;

I have a customer that did this, but through the FPGA on the board (can you?).
I don't know a whole lot about the project, but I know that they use the part
as a PSP to the PC, a watchdog protocol through the port, and power up/down
functions through the pic.  That customer is STILL chasing errant shut downs in
the design at this point.  It is the last problem with the product!  They
called me in for an opinion and I told them as politely as possible not to
trust the PSP completely.  I too had the same bad experiences with a (64??)
where the PSP interrupts never came.  Wasn't that an erratta in the past?  My
contribution was enlightening them to the use of an emulator to catch fast
problems from inside of the part.  They were unaware that they were using a
sledgehammer (windowed parts).  Their current rev simply exchanges messages
fast enough so that the estimated ten percent of lost messages (as yet
unexplained) are overlooked.  Nothing like using a pickup truck and a chain to
take the watchdog for a walk!

Although I haven't done the ISA to PSP myself, I would seriously reconsider
it.  Or make sure Windblows in on the system and blame the bi-daily crashes on
that!

Chris Eddy
Pioneer Microsystems, Inc.

Andy Kunz wrote:

> As much as I might dislike the idea (bad memories <G>), I'm involved in a
> project which requires that a 40-pin PIC be communicating bi-directionally
> with a PC on the ISA bus.
>
> If anybody has done this _SUCCESSFULLY_ I'd appreciate hearing from you for
> some pointers.  I received some code fragments a while back from somebody,
> but I can't find them and I forget who it was.
>
> Thanks.
>
> Andy
>
>    \-----------------/
>     \     /---\     /
>      \    |   |    /          Andy Kunz
>       \   /---\   /           Montana Design
> /---------+   +---------\     http://www.montanadesign.com
> | /  |----|___|----|  \ |
> \/___|      *      |___\/     Go fast, turn right,
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