Datasheet

At the Feather 32u4's heart is at ATmega32u4 clocked at 8 MHz and at 3.3V logic, a chip setup we've had tons of

experience with as it's the same as the Flora (https://adafru.it/dVl). This chip has 32K of flash and 2K of RAM, with built

in USB so not only does it have a USB-to-Serial program & debug capability built in with no need for an FTDI-like chip, it

can also act like a mouse, keyboard, USB MIDI device, etc.

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