This project was another spinoff of my original psx-to-genesis adapter. The analog signal from the stick is used to activate the dpad signals, just as if you pushed them. This is nice because the earliest psx games like Tomb Raider I or the Arcade Greatest Hits series don't support the analog stick (it wasn't around yet), but using the dpad can hurt the gameplay (dpad Sinistar --yech). There are some companies that make a controller with a dpad almost like an analog stick, but I wanted the real McCoy.
,_ Red wire is 3.5v | Black wire is gnd | V __----__________________________----__ / xxxxxxxx \ / \ / \ | | | | | Right stick Left stick | | x x | / x x x B \ | x A | / _____________________________ \ ( / \ ) \ / \ / \_____/ \_____/ NOTE: back-side of controller board 3.5v 3.5v | | | | / / \___pot_a \___pot_b / 1.1v / 2.8v \ \ | | | | gnd gnd +---+--+---+ dpad_east__1OUT |1 +--+ 14| 3OUT______dpad_north dpad_west__2OUT |2 13| 4OUT______dpad_south 3.5v________VCC |3 12| GND_______gnd 1.7v__ 1.1v___-2In |4 LM339 11| +4In______2.8v ___1.7v psx_A__ \__________+2In |5 10| -4In____________/ ___psx_B |____-1In |6 9| +3In____| 2.8v_____+1In |7 8| -3In______1.1v +----------+ Note: the 1.7v is produced by connecting two 10k resistors between 3.5v and ground How it Works: The player pushes the playstation analog stick all the way right (east) The psx_A voltages rises from 1.6v to 3.5v. Once the psx_A voltage is greater than 2.8v, comparator #1 turns on The 1OUT pins changes from high impedance to grounded The dpad_east voltage changes from 3.5v to 0v The console reads the dpad_east low voltage as someone pushing the button.