ProMicro
ProMicro_UART 
USB to Serial, SPI, I2C or JTAG
Documentation 
All files can be found on Github.
Schematic
BoM
Hardware 
Layout
Gerbers
can be found within the Github repository.
USB to Serial, SPI, I2C or JTAG
All files can be found on Github.
can be found within the Github repository.