Information about the schematics of the PCB for the Logitech-built Philips-branded “Touchpad 22ER9017”, a SNES-looking 4-button joypad. It's quite clearly based off a Gravis gamepad.
It has 2 switches, one to toggle the cursor speed when emulating a pointing device, and one to make the joypad left-handed/upside-down.
The protocol used is a simple serial protocol, with the player telling the joypad when to send data. More information is available in this Technical Info - Pointing Devices document.
| J1 pin | Joypad | Din 8 pin | Cable colour | Reason |
|---|---|---|---|---|
| 1 (top) | GND | 5 | Brown | connects with metal shielding of switches |
| 2 | RXD | 2 | Black | (the only one left ;) |
| 3 | RTS | 7 | Red | connects through R1, a 150kΩ resistor (value used for pull-down in CMOS applications) |
| 4 (bottom) | 5V/VDD | 8 | Orange | connects through all the buttons and switches to an MCU pin) |
The GND, VDD and RTS values were guessed with the reasons indicated, and cross-referenced with this very confusing repair guide and the schematics for joypad pinouts in the SNEStoCDi project.
The only chip on the board is a DIP-16 Motorola XC705K1CP branded
as a Logitech 330078-00 LOGITECH 93.
