Getting started with MicroPython on the SAMD¶
Using MicroPython is a great way to get the most of your SAMD board. And vice versa, the SAMD chip is a great platform for using MicroPython. This tutorial will guide you through setting up MicroPython, getting a prompt, using the hardware peripherals, and controlling some external components.
Let’s get started!
Requirements¶
The first thing you need is a board with an SAMD chip. The MicroPython software supports the SAMD chip itself and any board should work. The main characteristic of a board is how the GPIO pins are connected to the outside world, and whether it includes a built-in USB-serial converter to make the UART available to your PC.
Names of pins will be given in this tutorial using the board names (“D0”) and it should be straightforward to find which pin this corresponds to on your particular board.
Powering the board¶
If your board has a USB connector on it then most likely it is powered through this when connected to your PC. Otherwise you will need to power it directly. Please refer to the documentation for your board for further details.
Getting the firmware¶
Firmware versions are provided at the MicroPython download page. You can download the most recent MicroPython firmware .uf2 file to load onto your SAMD device. From that download page you have two main choices:
stable firmware builds
daily firmware builds
If you are just starting with MicroPython, the best bet is to go for the stable firmware builds. If you are an advanced, experienced MicroPython SAMD user who would like to follow development closely and help with testing new features, there are daily builds. They run through the same rigid internal test sequence as the stable builds, but the firmware features may change.
Deploying the firmware¶
Once you have the MicroPython firmware you need to load it onto your SAMD device. Most of the boards support the following easy procedure for firmware upload.
Connect the board by an USB-A/USB-Micro cable to your PC.
Push the reset button twice. Then, a drive should pop up at the PC’s file manager. Many boards have a on-board RGB LED, which first lights up red, and then changes it’s colour to green. The timing of the double push is sometimes tricky. So you may have to try to get the proper rhythm.
Copy the .uf2 file to that newly opened drive. A LED on the board may flash a while. When the copy is finished, the board drive will disappear and the RGB led will turn from green to the initial state.
Serial prompt¶
Once you have the firmware on the device you can access the REPL (Python prompt) over USB.
From there you can follow the SAMD tutorial.
Troubleshooting installation problems¶
If you experience problems during flashing or with running firmware immediately after it, here are some troubleshooting recommendations:
Be aware of and try to exclude hardware problems. There are two common problems: bad power source quality, and worn-out/defective Flash ROM. Speaking of power source, not just raw amperage is important, but also low ripple and noise/EMI in general. The most reliable and convenient power source is a USB port.