The Arduino Pro Mini is an ultra-compact board based on the ATmega328P available in 3.3V/8MHz and 5V/16MHz variants. It has no USB chip, requiring an external FTDI adapter to program, but is ideal for size-constrained embedded projects.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | GND | Ground | GND |
| 2 | VCC | Power supply | PWR |
| 3 | A6 | Analog input only | ADC |
| 4 | A7 | Analog input only | ADC |
| 5 | RESET | Reset, active low | I/O |
| 6 | VCC | Power supply | PWR |
| 7 | A3 | Analog input 3 | ADC |
| 8 | A2 | Analog input 2 | ADC |
| 9 | A1 | Analog input 1 | ADC |
| 10 | A0 | Analog input 0 | ADC |
| 11 | GND | Ground | GND |
| 12 | D13 | SPI SCK, LED | BUS |
| 13 | D12 | SPI MISO | BUS |
| 14 | D11~ | SPI MOSI, PWM | BUS |
| 15 | D10~ | SPI SS, PWM | BUS |
| 16 | D9~ | Digital I/O, PWM | I/O |
| 17 | D8 | Digital I/O | I/O |
| 18 | D7 | Digital I/O | I/O |
| 19 | D6~ | Digital I/O, PWM | I/O |
| 20 | D5~ | Digital I/O, PWM | I/O |
| 21 | D4 | Digital I/O | I/O |
| 22 | D3~ | Digital I/O, PWM, INT1 | I/O |
| 23 | D2 | Digital I/O, INT0 | I/O |
| 24 | GND | Ground | GND |
| 25 | RESET | Reset | I/O |
| 26 | RX | UART receive | BUS |
| 27 | TX | UART transmit | BUS |
| 28 | VCC | Power supply | PWR |
| 29 | A4/SDA | I2C SDA | BUS |
| 30 | A5/SCL | I2C SCL | BUS |