A retro computer is no fun without a way to type into it. Happily, the Adafruit Host Feather can be used to convert almost any USB keyboard into a keyboard for the RunCPM emulator.

Start by grabbing the keyboard converter sketch from GitHub:

Now, make the appropriate settings in the Tools menu:

• For board, choose "Adafruit Feather RP2040 USB Host"
• For USB stack choose "Adafruit TinyUSB"

Un-plug the emulator/video feather from your computer and plug the USB Host feather into your computer using a USB cable while holding down the BOOT button. It's important that the correct board is plugged in at this step, so that the correct board is updated! Select "upload sketch".

After the upload is complete, open the serial monitor and plug a compatible USB keyboard into the USB A port on the USB Host Feather. When you type letters on the keyboard, they will be shown on the serial monitor window. The bytes are also being transmitted on the board's RX pin for RunCPM to receive.

Note that due to technical limitations, a keyboard's capslock and numlock LEDs (if present) will not light, but these keys do function in the normal fashion.

The keyboard is set to a QWERTY US English layout and can only be changed by editing the source code and recompiling.