Ideal general purpose feather processor with lots of IO. 
 
The board is fitted with an ARM Cortex M4 STM32F405 MCU. running at 168MHz with 
1024K Flash
192K RAM. 
 
We have fitted the following on the Feather
HUB75 compatible pin header, although you can use it for whatever you want - this header is buffered for 5V output use. 
3x Serial ports on the Feather Headers
2x I2C on feather Headers
1x UART header with DC supply input on connector
4MByte SPI flash. 
 
Adafruit have recently released a STM32F405 Feather based board as well, here. This will allow our PCB to run the Adafruit CircuitPython, and drive HUB75 displays from python!