It is Adafruit's first Feather that is specifically designed for use with CircuitPython! CircuitPython is our beginner-oriented flavor of MicroPython - and as the name hints at, its a small but full-featured version of the popular Python programming language specifically for use with circuitry and electronics.

Please note: CircuitPython does not come preloaded. See the full guide linked below for instructions on installing it.

That doesn't mean you cant also use it with Arduino IDE! 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.

Here's some handy specs!

Measures 2.0" x 0.9" x 0.28" (51mm x 23mm x 8mm) without headers soldered in
Light as a (large?) feather - 5 grams
ATSAMD21G18 @ 48MHz with 3.3V logic/power
256KB of FLASH + 32KB of RAM
No EEPROM
32.768 KHz crystal for clock generation & RTC
3.3V regulator with 500mA peak current output
USB native support, comes with USB bootloader and serial port debugging
You also get tons of pins - 20 GPIO pins
Hardware Serial, hardware I2C, hardware SPI support
PWM outputs on all pins
6 x 12-bit analog inputs
1 x 10-bit analog ouput (DAC)
Built in 100mA lipoly charger with charging status indicator LED
Pin #13 red LED for general purpose blinking
Power/enable pin
4 mounting holes
Reset button

The Feather M0 Express uses the extra space left over to add a Mini NeoPixel, 2 MB SPI Flash storage and a little prototyping space. You can use the SPI Flash storage like a very tiny hard drive. When used in CircuitPython, the 2 MB flash acts as storage for all your scripts, libraries and files. When used in Arduino, you can read/write files to it, like a little datalogger or SD card, and then with our helper program, access the files over USB.

Easy reprogramming: the Feather M0 comes pre-loaded with the UF2 bootloader, which looks like a USB storage key. Simply drag firmware on to program, no special tools or drivers needed! It can be used to load up CircuitPython, PXT MakeCode or Arduino IDE (it is bossa-compatible)

Comes fully assembled and tested, with the UF2 USB bootloader. We also toss in some header so you can solder it in and plug into a solderless breadboard.

Lipoly battery and USB cable not included (but we do have lots of options in the shop if you'd like!