Joystick PCB Layout
From wiki.gp2x.org
(Looking at top of PCB - the side that the joystick is actually on - not the side it's soldered!)
U COM UL UR R COM COM L DL DR JS D
where
COM = Common U = Up D = Down L = Left R = Right UL = Up Left UR = Up Right DL = Down Left DR = Down Right JS = Joystick Button
All joysticks are pulled to ground on use (ie. Active low).