Arduino UNO R3 User Manual

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)

Arduino UNO R3 Specifications

General

Microcontroller	ATmega328P
Operating Voltage	5V
Input Voltage (recommended)	7-12V
Input Voltage (limit)	6-20V
Digital I/O Pins	14 (of which 6 provide PWM output)
PWM Digital I/O Pins	6
Analog Input Pins	6
DC Current per I/O Pin	20 mA
DC Current for 3.3V Pin	50 mA
Flash Memory	32 KB (ATmega328P) of which 0.5 KB used by bootloader
SRAM	2 KB (ATmega328P)
EEPROM	1 KB (ATmega328P)
Clock Speed	16 MHz
LED_BUILTIN	13
Length	68.6 mm
Width	53.4 mm
Weight	25 g

Summary

The Board

Application Examples

Explains how the Arduino UNO R3 is used for first projects, education, and industry.

Related Products

Lists related Arduino products like Starter Kits and robots.

Ratings

Recommended Operating Conditions

Details the conservative thermal limits for the Arduino UNO R3 board.

Power Consumption

Functional Overview

Board topology

Illustrates the physical layout of the Arduino UNO R3 board components.

Processor

Power Tree

Board Operation

Getting started - IDE

Guides on programming the Arduino UNO via the Desktop IDE and USB connection.

Getting started - Arduino Web Editor

Explains using the Arduino Web Editor for programming, requiring a browser plugin.

Getting started - Arduino IoT Cloud

Details using Arduino IoT Cloud for logging, graphing, and automating with IoT products.

Sample Sketches

Informs where to find example code within the Arduino IDE or website.

Online Resources

Directs users to ProjectHub, Library Reference, and the online store for further exploration.

Board Recovery

Connector Pinouts

JANALOG

Lists and describes analog pins and related functions on the Arduino UNO R3.

JDIGITAL

Lists and describes digital pins and related functions like SPI and I2C.

Mechanical Information

Board Outline & Mounting Holes

Certifications

Declaration of Conformity CE DOC (EU)

States conformity with essential EU Directives for market freedom.

Declaration of Conformity to EU RoHS & REACH 211 01/19/2021

Details compliance with RoHS and REACH regulations regarding hazardous substances.

Conflict Minerals Declaration

FCC Caution

Company Information

Reference Documentation

Revision History