Arduino A000066, Product Reference Manual, Page: 9 / 13

Arduino® UNO R3
9 / 13 Arduino® UNO R3 / Rev. 01 - 25/11/2021
5.1 JANALOG
Pin Function Type Description
1 NC NC Not connected
2 IOREF IOREF Reference for digital logic V - connected to 5V
3 Reset Reset Reset
4 +3V3 Power +3V3 Power Rail
5 +5V Power +5V Power Rail
6 GND Power Ground
7 GND Power Ground
8 VIN Power Voltage Input
9 A0 Analog/GPIO Analog input 0 /GPIO
10 A1 Analog/GPIO Analog input 1 /GPIO
11 A2 Analog/GPIO Analog input 2 /GPIO
12 A3 Analog/GPIO Analog input 3 /GPIO
13 A4/SDA Analog input/I2C Analog input 4/I2C Data line
14 A5/SCL Analog input/I2C Analog input 5/I2C Clock line
5.2 JDIGITAL
Pin Function Type Description
1 D0 Digital/GPIO Digital pin 0/GPIO
2 D1 Digital/GPIO Digital pin 1/GPIO
3 D2 Digital/GPIO Digital pin 2/GPIO
4 D3 Digital/GPIO Digital pin 3/GPIO
5 D4 Digital/GPIO Digital pin 4/GPIO
6 D5 Digital/GPIO Digital pin 5/GPIO
7 D6 Digital/GPIO Digital pin 6/GPIO
8 D7 Digital/GPIO Digital pin 7/GPIO
9 D8 Digital/GPIO Digital pin 8/GPIO
10 D9 Digital/GPIO Digital pin 9/GPIO
11 SS Digital SPI Chip Select
12 MOSI Digital SPI1 Main Out Secondary In
13 MISO Digital SPI Main In Secondary Out
14 SCK Digital SPI serial clock output
15 GND Power Ground
16 AREF Digital Analog reference voltage
17 A4/SD4 Digital Analog input 4/I2C Data line (duplicated)
18 A5/SD5 Digital Analog input 5/I2C Clock line (duplicated)