There are two programming pads located at the bottom of the Trinket M0:
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 Trinket and the SWD breakout:
- Trinket SWDIO to Breakout SWIO
- Trinket SWCLK to Breakout CLK
- Trinket 3Vo to Breakout VRef
- Trinket GND to Breakout GND