| Function | Port | CN3 Pin | - | CN4 Pin | Port | Function |
|---|---|---|---|---|---|---|
| USART1_TX | PA9 | 1 | - | 1 | VIN | - |
| UART1_RX | PA10 | 2 | - | 2 | GND | - |
| - | NRST | 3 | - | 3 | RESET | - |
| nRF905 GND | GND | 4 | - | 4 | +5V | - |
| - | PA12 | 5 | - | 5 | PA2 | DBG_USART_TX |
| - | PB0 | 6 | - | 6 | PA7 | - |
| - | PB7 | 7 | - | 7 | PA6 | nRF905 DR |
| - | PB6 | 8 | - | 8 | PA5 | nRF905 AM |
| - | PB1 | 9 | - | 9 | PA4 | nRF905 CD |
| - | PF0 | 10 | - | 10 | PA3 | nRF905 TRXCE |
| - | PF1 | 11 | - | 11 | PA1 | nRF905 TXE |
| - | PA8 | 12 | - | 12 | PA0 | nRF905 PWR |
| SPI1_CS | PA11 | 13 | - | 13 | AVDD | - |
| SPI1_MOSI | PB5 | 14 | - | 14 | +3V3 | nRF905 VCC |
| SPI1_MISO | PB4 | 15 | - | 15 | PB3 | SPI1_SCK |
