I'm trying to design a JAMMA adapter for the Arcadia Super Select System and while for the most part it's pretty straight forward there's one little wrinkle -
For the controls instead of the standard setup of having a common ground for all the switches and each action having its own separate signal/+5v wire this setup has the opposite, which is a common +5v shared by all the switches and the actions each having a separate ground. This is all because the Arcadia system uses an Amiga 500 as its main board and like most computers with analog joysticks at the time this is the scheme it's wired for.
The fix is obvious which is to just isolate the control ground, pump the +5 into that and route the grounds on the controls accordingly, but that would mean anyone using it would have to make that mod else risk frying things by dumping voltage into everything that is grounded, I'd rather not leave that even as a possibility, I want the adapter to be totally plug'n'play.
So my question is, does anyone know of a circuit I could build into the adapter to reverse its requirements to the normal JAMMA standard, thus removing the risks of having it want to put +5v in place of the control's ground? Any help will be appreciated.