Datasheet

The round pads on the right are for the ATSAMD21G18 (main processor). The rectangular

pads to the left are for the nrf51822 inside the BLE module.

You cannot connect these together to debug both at the same time!

Factory Reset

The (somewhat deceptively labeled) 'Reset' pad on the bottom of the PCB beside SWCLK

and SWDIO is for Factory Reset. Connecting this pad to GND at startup will perform a factory

reset, erasing any config settings and may be useful trying to recover a device in a faulty

state. Be sure to remove the connection to GND after the first power cycle.