| 1 | NC | Not Connected |
| 2 | GND | Ground |
| 3 | EXT_VDD | External power pin |
| 4 | VDD_P3V3 | Internal power pin |
| 5 | EXT_VDD | External power pin |
| 6 | VDD_P3V3 | Internal power pin |
| 7 | P1V8_5V GPIO3 | General purpose I/O pin |
| 8 | P1V8_5V GPIO4 | General purpose I/O pin |
| 9 | P1V8_5V GPIO1 | General purpose I/O pin |
| 10 | P1V8_5V GPIO2 | General purpose I/O pin |
| 11 | P1V8_5V_I2C_SDA | Data pin for I2C interface |
| 12 | P1V8_5V_I2C_SCL | Clock pin for I2C interface |
| 13 | P1V8_5V_UART_S_TX_M_RX | Receiver pin of the UART host device |
| 14 | P1V8_5V_UART_S_RX_M_TX | Transmitter pin of the UART host device |
| 15 | P1V8_5V_SPI_SS | Client Select for SPI. This pin must not connect to anything
else. |
| 16 | P1V8_5V_SPI_MOSI | SPI host out, client in pin |
| 17 | P1V8_5V_SPI_MISO | SPI host in, client out pin |
| 18 | P1V8_5V_SPI_SCK | SPI clock pin |
| 19 | GND | Ground |
| 20 | VDD_P3V3 | Power pin |
