Altera has published their "ByteBlaster-MV" schematic. It's not very different from the XILINX one, but I use ALTERA's circuit with the ALTERA software. I did, in a moment of madness build a crosspoint switch contained in a DB-25 connector shell, that allows me to move the driving signals between the parallel port connector and the 'HCT244, since that's what both use, but, while it seems to work just fine, I've never taken to using it. It's much easier to use the manufactured units.

If you want to build your own, then refer to,

http://opencollector.org/history/f...aster!.htm


Some of my ALTERA boards have the parallel port adapter built into them just as the DIGILENT boards once had. Note that they no longer do that. They (DIGILENT) rely on a 6-pin cable which they now sell separately from their boards. I rather liked the "old" way. The "old" way, used by DIGILENT, was also capable of supporting the EPP parallel port interface, which makes data transfers between PC's (not PC's running Windows, though) capable of much greater performance.

Good luck!

RE