The debugging interface on the Feathers are a little bit harder to get to than the ItsyBitsy and the Metro. They're on the bottom of the board - labeled SWDIO and SWCLK. We'll need to solder a wire to each of them.
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.
Make the following connections between the Feather and a SWD Breakout:
- Feather SWDIO to Breakout SWIO
- Feather SWCLK to Breakout CLK
- Feather 3V to Breakout VRef
- Feather GND to Breakout GND