Adafruit Feather M0 Basic Proto - ATSAMD21 Cortex M0

Key Features: ATSAMD21G18 ARM Cortex M0 processor - the same one used in the Arduino Zero 256K of FLASH (8x more than the Atmega328 or 32u4) and 32K of RAM (16x as much) Built in USB so it has USB-to-Serial program & debug capability built in with no need for an FTDI-like chip 3.7V Lithium polymer battery connector and built in battery charging Feather is the new development board from Adafruit, and like its namesake it is thin, light, and lets you fly! We designed Feather to be a new standard for portable microcontroller cores. This is the Feather M0 Basic Proto, it has a bunch of prototyping space built right in.To make it easy to use for portable projects, 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 meas