Programming and testing is accomplished via a 10 pin card-edge connector.
The pinout of this connector and mapping to a standard AVR 6-pin ISP is
given in the table below.

|| '''Pin''' || '''Name''' || '''Notes''' || '''ISP''' ||
|| 1 || 3.3V || Regulator output || 2 ||
|| 2 || TxD || UART TX output ||
|| 3 || RxD || UART RX input ||
|| 4 || SCK || SPI programming clock || 3 ||
|| 5 || Reset || CPU Reset || 5 ||
|| 6 || GND || || 6 ||
|| 7 || GND ||
|| 8 || BT+ || Battery voltage sense ||
|| 9 || MISO || SPI programming data out || 1 ||
|| 10 || MOSI || SPI programmming data in || 4 ||