CircuitPython is a programming language based on Python, and it is designed to work with low-cost microcontroller boards to make learning and tinkering easier. The Microchip ATSAMD21 is an inexpensive chip with the power to run CircuitPython.

Some SAMD21-based boards, like the Circuit Playground Express, METRO M0 Express, and Feather M0 Express, are designed to work with CircuitPython out of the box. Others, like the Arduino MKRZero, require a little more work.

This guide will show you how to install CircuitPython on a variety of SAMD21-based boards!

The easiest method for installing CircuitPython is through the UF2 bootloader. UF2 is a slick piece of code that runs on your microcontroller, and it allows the board to appear as a drive on your computer. From there, you can simply drag-and-drop the CircuitPython installer! We will need to take the following steps to install CircuitPython on a SAMD21 board:

• Install Arduino and the appropriate board definition
• Download the UF2 bootloader Arduino code for your board
• Upload the UF2 bootloader code to your board from Arduino
• Download the CircuitPython installer for your board
• Copy the CircuitPython installer to your board
• Test it!

Note that you only need to perform these steps once. Once you have installed CircuitPython on your board, you write CircuitPython code for it over and over again!