https://github.com/no0ne/ps2x2pico
USB keyboard/mouse to PS/2 interface converter using a Raspberry Pi Pico
https://github.com/no0ne/ps2x2pico
hid keyboard mouse pikvm pio ps2 ps2-keyboard ps2-mouse raspberry-pi-pico rp2040 usb-keyboard usb-mouse
Last synced: about 1 year ago
JSON representation
USB keyboard/mouse to PS/2 interface converter using a Raspberry Pi Pico
- Host: GitHub
- URL: https://github.com/no0ne/ps2x2pico
- Owner: No0ne
- License: mit
- Created: 2022-08-23T17:27:04.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2025-03-04T07:34:29.000Z (over 1 year ago)
- Last Synced: 2025-05-16T11:05:00.131Z (about 1 year ago)
- Topics: hid, keyboard, mouse, pikvm, pio, ps2, ps2-keyboard, ps2-mouse, raspberry-pi-pico, rp2040, usb-keyboard, usb-mouse
- Language: C
- Homepage:
- Size: 21.7 MB
- Stars: 295
- Watchers: 18
- Forks: 44
- Open Issues: 18
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# ps2x2pico
USB keyboard/mouse to PS/2 interface converter using a Raspberry Pi Pico
| | | | |
|-|-|-|-|
Keyboard only (incl. PC-XT) variant: https://github.com/No0ne/ps2pico
There is also an alternative ps2pico firmware for the PC-XT and ps2x2pico hardware: [ps2pico-XT-alt.uf2](https://github.com/No0ne/ps2pico/releases/tag/2.1)
Additional excellent documentation by Ray: https://minuszerodegrees.net/keyboard/ps2x2pico.htm
[PicoMiteVGA](https://geoffg.net/picomitevga.html) variant: https://github.com/No0ne/hid2cdc
[PiKVM](https://pikvm.org) integration:
* https://docs.pikvm.org/pico_hid/
* https://docs.pikvm.org/pico_hid_bridge/
[ITX-Llama](https://www.vogons.org/viewtopic.php?t=93480) integration:
https://github.com/eivindbohler/itxllama
# 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.
⚠️ Please note that some older motherboards have non-resettable fuses rated
under 300mA.
**Check the power consumption of your keyboard/mouse/hub first before plugging
in!**
⚠️ Do not assume wire colors will match cables depicted in photos. Double-check
your pinout with a multimeter.
# PS/2 passthru
If you also want to use a real PS/2 keyboard and mouse together with your USB devices you can mount another level shifter on top of the pico. These two ports work as PS/2 inputs and are passed through to the PS/2 output ports.
* GPIO3 LV1 - keyboard data
* GPIO4 LV2 - keyboard clock
* GPIO5 LV - 3.3V pull-up
* GND - GND
* GPIO6 LV3 - mouse data
* GPIO7 LV4 - mouse clock
Don't forget to wire HV to 5V and your PS/2 sockets to power the connected PS/2 devices.
PS/2 passthru is especially useful with the PiKVM [Pico HID](https://docs.pikvm.org/pico_hid/) or [Pico HID Bridge](https://docs.pikvm.org/pico_hid_bridge/) as you can continue using your existing peripherals.
⚠️ Please note that the [UF2 from PiKVM](https://github.com/pikvm/kvmd/releases) uses different GPIOs due to jumper pins:
* GPIO26 LV1 - keyboard data
* GPIO27 LV2 - keyboard clock
* GPIO16 LV3 - mouse data
* GPIO17 LV4 - mouse clock
Don't forget to wire LV to 3.3V and GND to GND separately as the level shifter does not fit directly on top of the pico.
# Troubleshooting
You can hook up a USB serial adapter to **GPIO0** for additional debugging output. The serial settings are **115200** baud, **8** data bits and **no parity**. You can also use another Pico running the [pico-uart-bridge](https://github.com/Noltari/pico-uart-bridge) for this.
⚠️ If you have a **YD-RP2040** (see silkscreen on back of board if unsure) and
are not using a USB hub with its own power supply, you need to bridge two pads
of the diode pair near the USB-C port as seen here:
# Build
Install needed libraries and tools:
```sh
sudo apt install cmake gcc-arm-none-eabi build-essential pkg-config libusb-1.0-0-dev libusb-1.0-0
```
Get the Raspberry Pi Pico SDK version 1.5.1:
```sh
git clone https://github.com/raspberrypi/pico-sdk
export PICO_SDK_PATH=/path/to/pico-sdk
cd $PICO_SDK_PATH
git checkout 1.5.1
git submodule update --init
```
Update to the latest TinyUSB release 0.17.0:
```sh
cd $PICO_SDK_PATH/lib/tinyusb
git checkout 0.17.0
```
Generate the UF2 file:
```sh
cd /path/to/ps2x2pico
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
* Archive.org links for the dead links in the pages above
* [Main page PS/2 Keyboard Protocol](https://web.archive.org/web/20160414014033if_/http://www.computer-engineering.org/ps2keyboard/)
* [Scan code set 1](https://web.archive.org/web/20160410193756if_/http://www.computer-engineering.org/ps2keyboard/scancodes1.html)
* [Scan code set 2](https://web.archive.org/web/20160414030011if_/http://www.computer-engineering.org/ps2keyboard/scancodes2.html)
* [Scan code set 3](https://web.archive.org/web/20160410184920if_/http://www.computer-engineering.org/ps2keyboard/scancodes3.html)
* [Main page PS/2 Mouse Protocol](https://web.archive.org/web/20160414013310if_/http://www.computer-engineering.org/ps2mouse/)