fio v3
https://learn.sparkfun.com/tutorials/pro-micro--fio-v3-hookup-guide/hardware-overview-fio-v3
http://www.switch-science.com/catalog/1147/
https://learn.sparkfun.com/tutorials/pro-micro--fio-v3-hookup-guide/installing-windows
https://dlnmh9ip6v2uc.cloudfront.net/datasheets/Dev/Arduino/Boards/32U4Note.pdf