Arduino AVR
Arduino Nano Pinout
The Arduino Nano is the Uno's compact cousin — same ATmega328P, same Arduino IDE compatibility, but laid out as a 30-pin DIP that drops straight into a breadboard. It also adds two extra analog inputs (A6, A7) the Uno doesn't expose.
Specifications
- MCU
- ATmega328P, 16 MHz
- Flash
- 32 KB (2 KB used by bootloader)
- SRAM
- 2 KB
- Digital I/O
- 14 (6 PWM-capable)
- Analog inputs
- 8 (A0–A7, 10-bit ADC)
- Operating voltage
- 5V (7–12V on VIN)
Pin reference
| Pin | Name | Type / functions | Notes |
|---|---|---|---|
| D0 | RX | Digital I/O, UART RX | Used by USB serial. |
| D1 | TX | Digital I/O, UART TX | Used by USB serial. |
| D2 | INT0 | Digital I/O, external interrupt | — |
| D3 | INT1 / PWM | Digital I/O, PWM, interrupt | — |
| D4 | D4 | Digital I/O | — |
| D5 | PWM | Digital I/O, PWM | — |
| D6 | PWM | Digital I/O, PWM | — |
| D7 | D7 | Digital I/O | — |
| D8 | D8 | Digital I/O | — |
| D9 | PWM | Digital I/O, PWM | — |
| D10 | SS / PWM | Digital I/O, SPI SS, PWM | — |
| D11 | MOSI / PWM | Digital I/O, SPI MOSI, PWM | — |
| D12 | MISO | Digital I/O, SPI MISO | — |
| D13 | SCK / LED | Digital I/O, SPI SCK, onboard LED | — |
| A0 | Analog 0 | Analog input / Digital I/O | — |
| A1 | Analog 1 | Analog input / Digital I/O | — |
| A2 | Analog 2 | Analog input / Digital I/O | — |
| A3 | Analog 3 | Analog input / Digital I/O | — |
| A4 | SDA | Analog input / I2C SDA | — |
| A5 | SCL | Analog input / I2C SCL | — |
| A6 | Analog 6 | Analog input only | Cannot be used as digital I/O. |
| A7 | Analog 7 | Analog input only | Cannot be used as digital I/O. |
| AREF | Analog reference | Reference voltage for ADC | — |
| VIN | VIN | Power input, 7–12V | — |
| 5V | 5V output | Regulated 5V, ~500 mA | — |
| 3V3 | 3.3V output | Regulated 3.3V, ~50 mA | — |
| GND | Ground | Power | — |
| RESET | Reset | Pull LOW to reset | — |
Gotchas
- 01A6 and A7 are analog-input ONLY. Calling digitalRead/digitalWrite on them does nothing.
- 02Older Nanos use the CH340 USB-serial chip, which needs a separate driver on macOS and Windows.
- 03The 3.3V rail is generated by the FTDI/CH340 chip and can only supply ~50 mA.
- 04Only D2 and D3 support hardware interrupts.
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