https://github.com/no0ne/ps2pico

USB keyboard to PS/2 / AT / XT interface converter using a Raspberry Pi Pico
https://github.com/no0ne/ps2pico

at-keyboard hid keyboard pc-at pc-xt pcat pcxt pio ps2 ps2-keyboard raspberry-pi-pico rp2040 usb-keyboard xt-keyboard

Last synced: about 4 hours ago
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USB keyboard to PS/2 / AT / XT interface converter using a Raspberry Pi Pico

• Host: GitHub
• URL: https://github.com/no0ne/ps2pico
• Owner: No0ne
• License: mit
• Created: 2022-07-16T17:40:28.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2024-05-26T08:02:37.000Z (6 months ago)
• Last Synced: 2024-10-30T21:04:03.735Z (14 days ago)
• Topics: at-keyboard, hid, keyboard, pc-at, pc-xt, pcat, pcxt, pio, ps2, ps2-keyboard, raspberry-pi-pico, rp2040, usb-keyboard, xt-keyboard
• Language: C
• Homepage:
• Size: 1020 KB
• Stars: 120
• Watchers: 14
• Forks: 24
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# ps2pico

USB keyboard to PS/2+AT or XT interface converter using a Raspberry Pi Pico

|![hw1](https://raw.githubusercontent.com/No0ne/ps2pico/main/doc/hw1.jpg) |![hw2](https://raw.githubusercontent.com/No0ne/ps2pico/main/doc/hw2.jpg) |![hw3](https://raw.githubusercontent.com/No0ne/ps2pico/main/doc/hw3.jpg) |![hw4](https://raw.githubusercontent.com/No0ne/ps2pico/main/doc/hw4.jpg) |

|-|-|-|-|

Keyboard + Mouse variant: https://github.com/No0ne/ps2x2pico

# Usage

* Download `ps2pico.uf2` or `ps2pico-XT.uf2` from https://github.com/No0ne/ps2pico/releases

* Copy `ps2pico.uf2` or `ps2pico-XT.uf2` to your Pi Pico by pressing BOOTSEL before pluggging in.

* Afterwards connect a USB keyboard using an OTG-adapter and PS/2+AT or XT 5V to Pico VBUS.

* Also works with wireless keyboards with a dedicated USB receiver.

* 3.3V/5V conversion is done with two NPN transistors, two zener diodes and four resistors as shown below:

```

                 PS/2+AT / XT CLOCK

                       |           ____

                       |__________|10k |___________ GPIO 14

            ____       |          |____|     |

GPIO 15 ___|2k2 |____|/  BC547             __|__

           |____|    |\e                    / \  3V6

                       |                     |

                   ____|__GND________________|___

                 PS/2+AT / XT DATA

                       |          ____

                       |_________|10k |____________ GPIO 17

            ____       |         |____|      |

GPIO 16 ___|2k2 |____|/  BC547             __|__

           |____|    |\e                    / \  3V6

                       |                     |

                   ____|__GND________________|___

```

![ps2pico](https://github.com/No0ne/ps2pico/assets/716129/b0133c44-c170-40f4-a3ad-c545aee92532)

# NuXTv2

If you have a [NuXTv2](https://monotech.fwscart.com/NuXT_v20_-_MicroATX_Turbo_XT_-_10MHz_832K_XT-IDE_Multi-IO_SVGA/p6083514_19777986.aspx) you can build an internal version of the ps2pico-XT! Replace U10 with the pico, remove RN13 and add two 4k7 pull-up resistors as shown below:

|![hw5](https://raw.githubusercontent.com/No0ne/ps2pico/main/doc/hw5.jpg) |![hw6](https://raw.githubusercontent.com/No0ne/ps2pico/main/doc/hw6.jpg) |![hw7](https://raw.githubusercontent.com/No0ne/ps2pico/main/doc/hw7.jpg) |

|-|-|-|

# Build

```

export PICO_SDK_PATH=/path/to/pico-sdk

mkdir build

cd build

cmake ..

make

```

# Resources

* https://wiki.osdev.org/PS/2_Keyboard

* https://github.com/Harvie/ps2dev/blob/master/src/ps2dev.cpp

* http://www.lucadavidian.com/2017/11/15/interfacing-ps2-keyboard-to-a-microcontroller/

* https://download.microsoft.com/download/1/6/1/161ba512-40e2-4cc9-843a-923143f3456c/translate.pdf

* https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-XT-Keyboard-Protocol

* https://github.com/AndersBNielsen/pcxtkbd/blob/master/XT_KEYBOARD.ino