Project for an IBM M122 keyboard controller
This is a project that replaces the original part from IBM with a nice modern solution. It features a nRF52840 microcontroller and allows to use the keyboard via USB connector, or via Bluetooth.
The firmware is based on the ZMK project.
Beside the assembled PCB you require:
- A matching IBM Keyboard
- An external LiPO cell - the unit was designed with a LP103048JU 1.500 m Ah cell in mind
- One 8 pin connector for the flat flex coming from the keyboad 5-520315-8 from AMP DigiKey P/N 5-520315-8-ND
- One 20 pin connector for the flat flex coming from the keyboad 7-520355-0 from AMP DigiKey P/N A144436-ND
You need a debug adapter (JLink) with 6 pin Tag-Connect for the initial flash programming of the board
When ordering the pcb from JLC you need to specify
- Via Covering Epoxy Filled & Capped
- Min via hole size 0.2 mm
- Use the nrf-Flash-Tool to flash the bootloader to the nrf52840
- Use drag-and-drop of the uf2 build output to flash the keyboard firmware
Set the zmk project up as described in Toolchain Setup. Go to the zmk base directory, then run cd app west build --board nrf52840_m122 . -- -DZMK_EXTRA_MODULE=(..)/m122_keyboard/zmk-config
The project uses the Adafruit bootloader.