Did you see the Adafruit Feather M0 Express board was released this week?  This is a new Feather development board that’s built with the familiar Atmel SAMD21 microprocessor (the same chip in the Arduino Zero and other Feather M0 boards) but has a few nifty additions for CircuitPython.  The most important addition is a tiny 2 megabyte flash chip which can be used to store Python scripts and other data files.  By storing code on an external flash chip it frees up all of the flash memory of the SAMD21 processor for CircuitPython’s firmware–this means more features and support can be added to the CircuitPython firmware.  There’s also a tiny NeoPixel built into the board which can be used by CircuitPython to indicate status, like if it’s ready to automatically run scripts, is writing to flash memory, and more.

In addition to CircuitPython support the Feather M0 Express can be programmed with the Arduino IDE just like other M0 boards.  Be sure to update Adafruit’s boards in Arduino’s board manager to see the new Feather M0 Express board.

Right now CircuitPython is in beta so you need to manually load it on the Feather M0 Express.  Luckily this process is super easy with a new UF2 bootloader which supports dragging and dropping firmware onto the board just like a USB drive.  Check out the documentation for full details on how to load CircuitPython on the Feather M0 Express, but here’s a quick summary:

1. Download the latest CircuitPython Feather M0 Express .uf2 file from the CircuitPython releases page on GitHub. Remember you want the .uf2 file, not the .bin file!
2. Plug the Feather M0 Express board into your computer’s USB port.  Double tap the reset button, you should see the red LED (not the NeoPixel, the small #13 red LED near the USB port) start to pulse indicating it’s in bootloader mode.
3. Notice a new FEATHERBOOT USB drive appears connected to your computer.  This is a special UF2 loading mode for the bootloader, simply drag the .uf2 file downloaded above onto the FEATHERBOOT drive.  The bootloader will recognize the firmware file and start flashing it to the chip (the red LED will start to flash quickly indicating it’s writing the firmware).
   
4. That’s it!  CircuitPython is now loaded on the Feather M0 Express!  You can now connect to the board’s serial REPL, start editing Python code, and have fun exploring CircuitPython!

Check out the Feather M0 Express guide for more details about the board hardware, using it with Arduino, and using it with CircuitPython!