Loading source-backed pinouts…
Board overview
Arduino UNO Rev3
Arduino · Classic
Pin search cleared
Filter pins
Showing 25 of 25 pins
Simplified technical illustration. Pin data is source-backed; verify against the linked documentation before wiring.
Hover, tap, or focus a pad to inspect a pin. Use arrow keys to move between pins.
Mapped source · Arduino UNO Rev3 full pinout PDFOfficial- UNO Rev3 and UNO R4 share the classic shield header footprint and 5 V operating voltage, but MCU-specific alternate functions differ.
- SPI is exposed on the ICSP header; D10 through D13 are commonly used with SPI shields.
- A4 and A5 are the default I2C SDA/SCL pins on the UNO-style header.
All 25 pins
| # | Signal | Role | Net | Also / notes |
|---|---|---|---|---|
| Digital | ||||
| 1 | UART | UART | ||
| 2 | UART | UART | ||
| 3 | GPIO | |||
| 4 | PWM | |||
| 5 | GPIO | |||
| 6 | PWM | |||
| 7 | PWM | |||
| 8 | GPIO | |||
| 9 | GPIO | |||
| 10 | PWM | |||
| 11 | SPI | SPI | ||
| 12 | SPI | SPI | ||
| 13 | SPI | SPI | ||
| 14 | SPI | SPI | ||
| Analog / Power | ||||
| 14 | ADC | |||
| 15 | ADC | |||
| 16 | ADC | |||
| 17 | ADC | |||
| 18 | I2C | I2C | ||
| 19 | I2C | I2C | ||
| 20 | Power | 3V3 | ||
| 21 | Power | 5V | ||
| 22 | Ground | GND | ||
| 23 | Power | VIN | ||
| 24 | System | |||