When I wanted to assign a letter for the Saturn controller my first thought was "S", but it turns out Sega already assigned that to the steering wheel (and I wouldn't put it past people to try to make use of the steering wheel in homebrew or hacks if adapters become more common). And the Saturn's letter for its controller is predictably "J", which obviously we can't use for it…
Another issue comes with the keyboard, since "K" nominally means keyboard, but on the Mega Drive in practice it ended up being used to refer to the Ten Key Pad (Mega Anser reports "K" in its device field), which has nothing to do with the Saturn keyboard.
I'd say something about the mouse but Sega straight up reused the packet format, so Saturn and Mega Drive mouses are compatible (lol)
Anyway, does anybody have any suggestions about how we should map support for Saturn peripherals on a Mega Drive? I know most of the ROM header goes ignored in practice and that the device field is one of the worst offenders but keeping it usable as much as possible would be nice. One idea I had was to use lowercase letters but it feels awkward (on the other hand, all of the Saturn peripherals seem to be identified by letters).
For context, list taken from "SEGA SATURN TECHNICAL BULLETIN #40":
- J: controller
- A: mission stick
- M: mouse
- K: keyboard
- S: steering wheel
- T: multitap
- G: lightgun
- C: Saturn-to-Saturn cable
- P: MPEG card
- F: floppy drive
- D: modem
- X: XBAND