qmk_firmware/keyboard/onekey
..
Makefile
Makefile.pjrc
Makefile.vusb
README.md
config.h
keymap.c
led.c
matrix.c
usbconfig.h

README.md

Onekey

Just one key keyboard for example. It sends 'a' key if pins PB0 and PB1 are short-circuited.

https://github.com/tmk/tmk_keyboard/issues/56