We love all our Feathers equally, but this Feather is very special. It's our 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.

The Feather M0's SAMD21 is a very minimal chip for CircuitPython, at the time it was the first board we designed that could use it but chips have gotten better since then. To really have a good experience we recommend a Feather M4

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.

You can also use MakeCode's block-based GUI coding on this board.

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 Circuit Python, 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.

Comes fully assembled and tested, with a USB bootloader that lets you quickly use it with the Arduino IDE or for loading Circuit Python. 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!)

This guide was first published on Mar 31, 2017. It was last updated on Mar 13, 2024.

This page (Overview) was last updated on Mar 08, 2024.

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