add alternate DB25 connection(s)

[garlick]

Problem: the ribbon cable from the board to the DB25 connector is bulky and constrains where the board can be deployed

If we can make room, consider adding alternate footprints. The end user could choose which one to populate:

• existing 2.54 pitch dual row header
• a fine pitch header or FPC (which would imply an adapter board at the DB25 end)
• a DB25 footprint for direct mounting on the board (making space for that may be a reach!)

[garlick]

It doesn't really seem feasible to do a DB-25 on board in the normal HAT profile. I tried, but a board-secured DB-25 footprint overlaps with the HAT standoff holes on the long edge. The HAT+ spec allows the board to be any shape but then a custom or topless case would be required.

Edit: also it seems like the weight of the DB25 cable and connector would always be toppling over the little pi, which would be annoying.

As mentioned, the FPC connector would necessitate another board on the DB25 end so that is a bit of a downside for that idea.

I think I'll just close this. @quorten - fee free to reopen if you think we should try harder.