STM32 Nucleo Arduino-compatible headers (CN5 CN6 CN8 CN9) follow the Arduino Uno R3 pinout for shield compatibility, providing analog inputs, digital I/O, SPI, I2C, and UART on standard 2.54mm headers.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | NC | Not connected | I/O |
| 2 | IOREF | 3.3V I/O reference | I/O |
| 3 | RESET | Reset | I/O |
| 4 | 3V3 | 3.3V power | PWR |
| 5 | 5V | 5V power | PWR |
| 6 | GND | Ground | GND |
| 7 | GND | Ground | GND |
| 8 | VIN | Input voltage | PWR |
| A0 | PA0 | ADC channel 0 | ADC |
| A1 | PA1 | ADC channel 1 | ADC |
| A2 | PA4 | ADC channel 2 DAC | ADC |
| A3 | PB0 | ADC channel 3 | ADC |
| A4 | PC1 | ADC SDA | ADC |
| A5 | PC0 | ADC SCL | ADC |