Compiling BlueMicro firmware for the nice!nano
Install Arduino IDE Install adafruit NRF boards (preferences -> additional boards manager URL, bottom of the first tab), url: http://adafruit.github.io/arduino-board-index/package_adafruit_index.json
Clone repo: https://github.com/jpconstantineau/BlueMicro_BLE Get python converter script: https://raw.githubusercontent.com/microsoft/uf2/master/utils/uf2conv.py
Copy new keyboard from existing board folder; I used crkbd. . Set up the KEYMAP macro in keyboard_config.h, along with all your device names and such. Set KEYBOARD_SIDE accordingly, also. The hardware_config.h should define your row and column pins; the pins are numbered slightly oddly: for 0.n, the pin number is n, for 1.n, the pin number is 32+n. Refer to pinouts: https://docs.nicekeyboards.com/#/nice!nano/pinout_schematic to get the numbers. Also define MATRIX_ROW_PINS, MATRIX_COL_PINS in hardware_config, and set DIODE_DIRECTION to match your matrix.
Keymap.cpp defines your keymap; worth spending some time there to get it right. Keymap.h I don't think I touched from the project I copied from.
Folder structure should look something like this:
Cd to /build/macOS. Copy hardware_config.h, keyboard_config.h, and keycap.h to /firmware. Change the script build-macos like so:

Then, still from /build/macOS, run: ./build-macos <keyboard folder name>:<layout name, default in my folders above>:config --fqbn adafruit:nrf52:pca10056:softdevice=s140v6. This will run a compiler and build a .hex file. Now we can convert that to a uf2 file for drag-and-drop flashing: python uf2conv.py -f 0xADA52840 -c -o nrf52840_xxaa.uf2 ../../output/atreus_62/atreus_62-default-config.hex (this assumes you have the downloaded MS script in the current folder.
Last: double tap the reset button or short the reset pin to ground twice quickly with the device plugged in to your computer. It should pop up as a drive. Drag the generated uf2 file to the drive, and it should automatically reset. Congratulation, you’ve done it.
