Datasheet

At the Feather M0's heart is an ATSAMD21G18 ARM Cortex M0 processor, clocked at 48 MHz

and at 3.3V logic, the same one used in the new Arduino Zero. This chip has a whopping

256K of FLASH (8x more than the Atmega328 or 32u4) and 32K of RAM (16x as much)! This

chip comes with built in USB so it has USB-to-Serial program & debug capability built in with

no need for an FTDI-like chip.

To make it easy to use for portable projects, we added a connector for any of our 3.7V

Lithium polymer batteries and built in battery charging. You don't need a battery, it will run

just fine straight from the micro USB connector. But, if you do have a battery, you can take it

on the go, then plug in the USB to recharge. The Feather will automatically switch over to

USB power when its available. We also tied the battery thru a divider to an analog pin, so

you can measure and monitor the battery voltage to detect when you need a recharge.