Pinout PAD GPIO Usage 1 SWD - 2 SWC - 3 P0.21 RST 4 VCC - 5 GND - 6 P0.12 SDA 7 P0.05 SCL 8 P0.00 9 P0.04 LED 10 P0.01 11 P0.20 RXD 12 P0.14 TXD 13 P0.16 14 GND - 15 P0.18