Ok, I went and looked at Jon's stuff. I have in fact looked at it before. It seems he has lots of EMC side stuff available there.

For the PIC side I wanted to use the PSP hardware, but I don't think I can. PSP has 3 handshake lines, /CS /RD /WR. As I understand it, EPP port has 4, /WR /DataStrobe /AddressStrobe and Wait.
/WR /DS /AS are inputs to the pic and Wait is output from the PIC. And of course the 8 data lines. /DS and /AS start a transmission as long as wait is low. So it seems to me it would make sense to have /DS & /AS as IOC then do the comm in an ISR. Now I am pretty sure at this point the uP won't be doing anything else while waiting for the PC to start a transfer, at which time data coming in can be sent directly to which ever port it needs to go to and data going out will just be ports reads and send.

I guess this is going to start out as a large I/O card with no smarts to speak of. So maybe just pool the /DS and /AS.

Hmmm... thoughts anyone?