On the bottom of the Gemma, there are three small pads used for programming:

Cut and strip two wires.


Solder one of them to the SWDIO pad and the other to the SWCLK pad, making sure that the two wires do not touch. 


After soldering, add a small piece of tape to secure the connection between the wire and the pad.

Then, make the following connections between the Gemma and the SWD breakout:


  • Gemma SWDIO to Breakout SWIO
  • Gemma SWCLK to Breakout CLK
  • Gemma 3Vo to Breakout VRef
  • Gemma GND to Breakout GND


You can use breadboard-friendly Alligator clips to attach the Gemma M0's 3Vo and GND pins to the breakout.

You must also plug in a USB cable to the Gemma to power it during progamming

This guide was first published on Jan 25, 2019. It was last updated on Mar 08, 2024.

This page (Gemma M0 Wiring) was last updated on Mar 08, 2024.

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