Adafruit feather main boards adafruit 2772 the adafruit feather atsamd21g18 basic proto board has all the features of a standard feather board plus a 5 x 8 pad prototyping area the atmel atsamd21g18 is a very interesting chip its the one chosen to power the arduino zero so you know it will be supported by arduino development tools libraries and ides it has a cortex m0 core with 256kbytes of flash memory 32kbytes of ram and runs at 48mhz and 33v dc compared to the atmel 32u4 it has 8