ps2x2pico

USB keyboard/mouse to PS/2 interface converter using a Raspberry Pi Pico

Keyboard only variant: https://github.com/No0ne/ps2pico

PC-XT variant: https://github.com/No0ne/ps2pico/tree/xt-version

PiKVM integration: https://docs.pikvm.org/pico_hid/

Usage

• Download ps2x2pico.uf2 from https://github.com/No0ne/ps2x2pico/releases
• Copy ps2x2pico.uf2 to your Pi Pico by pressing BOOTSEL before pluggging in.
• 3.3V/5V conversion is done using a bi-directional level shifter: https://learn.sparkfun.com/tutorials/bi-directional-logic-level-converter-hookup-guide/
• Afterwards connect a USB keyboard and/or mouse using an OTG-adapter and optional USB hub.
• Also works with wireless keyboards and mice with a dedicated USB receiver.

                   _________________
                  |                 |
Pico GPIO11 ______| LV1         HV1 |______ PS/2 keyboard data
Pico GPIO12 ______| LV2         HV2 |______ PS/2 keyboard clock
Pico GPIO13 ______| LV          HV  |______ PS/2 5V + Pico VBUS
Pico    GND ______| GND         GND |______ PS/2 GND
Pico GPIO14 ______| LV3         HV3 |______ PS/2 mouse data
Pico GPIO15 ______| LV4         HV4 |______ PS/2 mouse clock
                  |_________________|

Build

export PICO_SDK_PATH=/path/to/pico-sdk
mkdir build
cd build
cmake ..
make

Resources

• https://github.com/No0ne/ps2pico
• https://wiki.osdev.org/PS/2_Keyboard
• https://wiki.osdev.org/PS/2_Mouse
• https://wiki.osdev.org/Mouse_Input
• https://wiki.osdev.org/%228042%22_PS/2_Controller
• http://www-ug.eecg.toronto.edu/msl/nios_devices/datasheets/PS2%20Keyboard%20Protocol.htm
• http://www-ug.eecg.utoronto.ca/desl/nios_devices_SoC/datasheets/PS2%20Mouse%20Protocol.htm