Posted by Keith O on 9, 2001 at 7:36 PM:
In Reply to: Hacking a Gravis Gamepad Pro USB posted by Dan_Fanatic on 9, 2001 at 5:37 PM:
I hacked a Gravis GamePad Pro (non-usb). It turns out that all the buttons have a common ground except d-pad up and d-pad left. I know this sounds weird but it's true. However, after I had all the buttons programmed in mame, I noticed that the little switch underneath the joystick was set to the GrIP setting (two player mode - I think). Instead of reprogramming my setup, I just kept it in that mode. This may have something to do with why my setup has two grounds. Anyway, I believe the USB version doesn't have to deal with GrIP so you may have only one ground. The only way to know for sure is to just jump right in and start testing the contacts. Good luck!