I am designign an custom PCB, that uses an ATSAMD21G18A-AU as the main Chip. Because it comes from the factory it needs a bootloader or another way to add software, so I need a JTAGICE3 connector or an Cortex Debug Connector. Both are supported, as they are shown in the official documentation of the MCU.

Now I am trying to find the right connector, but cant find anything. I did found the J-Link EDU Mini, but can I use it and if yes, can I then use OpenOCD to connect the MCU to my PC and load code or a boot loader to it?

Finally, where can I find the correct bootloader? Ultimately I want to run MicroPython on it and want it to function similar to a pi pico. So I will need a UF2-Bootloader, I think, but where can I get it and does the MCU support MicroPython?



1 Answer 1


The SWD connector for your PCB should be a 2x5 male header with 0.050" (1.27mm) spacing.

Pinout from JTAGICE3 datasheet: enter image description here

You can then use J-Link EDU Mini with OpenOCD to upload bootloader, application or debugging.

The instructions to upload a UF2 bootloader and use MicroPython are in this Adafruit tutorial.

enter image description here


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