Arduino® UNO R3
Product Reference Manual
SKU: A000066
Description
The Arduino UNO R3 is the perfect board to get familiar with electronics and coding. This versatile development
board is equipped with the well-known ATmega328P and the ATMega 16U2 Processor.
This board will give you a great first experience within the world of Arduino.
Target areas:
Maker, introduction, industries
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Features
ATMega328P Processor
Memory
AVR CPU at up to 16 MHz
32KB Flash
2KB SRAM
1KB EEPROM
Security
Power On Reset (POR)
Brown Out Detection (BOD)
Peripherals
2x 8-bit Timer/Counter with a dedicated period register and compare channels
1x 16-bit Timer/Counter with a dedicated period register, input capture and compare channels
1x USART with fractional baud rate generator and start-of-frame detection
1x controller/peripheral Serial Peripheral Interface (SPI)
1x Dual mode controller/peripheral I2C
1x Analog Comparator (AC) with a scalable reference input
Watchdog Timer with separate on-chip oscillator
Six PWM channels
Interrupt and wake-up on pin change
ATMega16U2 Processor
8-bit AVR® RISC-based microcontroller
Memory
16 KB ISP Flash
512B EEPROM
512B SRAM
debugWIRE interface for on-chip debugging and programming
Power
2.7-5.5 volts
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CONTENTS
1 The Board 4
1.1 Application Examples 4
1.2 Related Products 4
2 Ratings 5
2.1 Recommended Operating Conditions 5
2.2 Power Consumption 5
3 Functional Overview 5
3.1 Board Topology 5
3.2 Processor 6
3.3 Power Tree 7
4 Board Operation 8
4.1 Getting Started - IDE 8
4.2 Getting Started - Arduino Web Editor 8
4.3 Sample Sketches 8
4.4 Online Resources 8
5 Connector Pinouts 9
5.1 JANALOG 10
5.2 JDIGITAL 10
5.3 Mechanical Information 11
5.4 Board Outline & Mounting Holes 11
6 Certifications 12
6.1 Declaration of Conformity CE DoC (EU) 12
6.2 Declaration of Conformity to EU RoHS & REACH 211 01/19/2021 12
6.3 Conflict Minerals Declaration 13
7 FCC Caution 13
8 Company Information 14
9 Reference Documentation 14
10 Revision History 14
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1 The Board
1.1 Application Examples
The UNO board is the flagship product of Arduino. Regardless if you are new to the world of electronics or will use
the UNO as a tool for education purposes or industry-related tasks, the UNO is likely to meet your needs.
First entry to electronics: If this is your first project within coding and electronics, get started with our most used
and documented board; Arduino UNO. It is equipped with the well-known ATmega328P processor, 14 digital
input/output pins, 6 analog inputs, USB connections, ICSP header and reset button. This board includes everything
you will need for a great first experience with Arduino.
Industry-standard development board: Using the Arduino UNO R3 board in industries, there are a range of
companies using the UNO board as the brain for their PLC’s.
Education purposes: Although the UNO R3 board has been with us for about ten years, it is still widely used for
various education purposes and scientific projects. The board's high standard and top quality performance makes
it a great resource to capture real time from sensors and to trigger complex laboratory equipment to mention a few
examples.
1.2 Related Products
Starter Kit
Arduino UNO R4 Minima
Arduino UNO R4 WiFi
Tinkerkit Braccio Robot
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2 Ratings
2.1 Recommended Operating Conditions
Symbol Description Min Max
Conservative thermal limits for the whole board: -40 °C (-40°F) 85 °C ( 185°F)
NOTE: In extreme temperatures, EEPROM, voltage regulator, and the crystal oscillator, might not
work as expected.
2.2 Power Consumption
Symbol Description Min Typ Max Unit
VINMax Maximum input voltage from VIN pad 6 - 20 V
VUSBMax Maximum input voltage from USB connector - 5.5 V
PMax Maximum Power Consumption - - xx mA
3 Functional Overview
3.1 Board Topology
Top view
Board topology
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Ref. Description Ref. Description
X1 Power jack 2.1x5.5mm U1 SPX1117M3-L-5 Regulator
X2 USB B Connector U3 ATMEGA16U2 Module
PC1 EEE-1EA470WP 25V SMD Capacitor U5 LMV358LIST-A.9 IC
PC2 EEE-1EA470WP 25V SMD Capacitor F1 Chip Capacitor, High Density
D1 CGRA4007-G Rectifier ICSP Pin header connector (through hole 6)
J-ZU4 ATMEGA328P Module ICSP1 Pin header connector (through hole 6)
Y1 ECS-160-20-4X-DU Oscillator
3.2 Processor
The Main Processor is a ATmega328P running at up to 20 MHz. Most of its pins are connected to the external
headers, however some are reserved for internal communication with the USB Bridge coprocessor.
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3.3 Power Tree
Power tree
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4 Board Operation
4.1 Getting Started - IDE
If you want to program your Arduino UNO R3 while offline you need to install the Arduino Desktop IDE [1] To
connect the Arduino UNO to your computer, you’ll need a USB-B cable. This also provides power to the board, as
indicated by the LED.
4.2 Getting Started - Arduino Web Editor
All Arduino boards, including this one, work out-of-the-box on the Arduino Web Editor [2], by just installing a simple
plugin.
The Arduino Web Editor is hosted online, therefore it will always be up-to-date with the latest features and support
for all boards. Follow [3] to start coding on the browser and upload your sketches onto your board.
4.3 Sample Sketches
Sample sketches for the Arduino UNO R3 can be found either in the “Examples” menu in the Arduino IDE or in the
“Documentation” section of the Arduino website [4]
4.4 Online Resources
Now that you have gone through the basics of what you can do with the board you can explore the endless
possibilities it provides by checking exciting projects on Arduino Project Hub [5], the Arduino Library Reference [6]
and the online Arduino store [7] where you will be able to complement your board with sensors, actuators and
more.
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5 Connector Pinouts
Pinout
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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)
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5.3 Mechanical Information
5.4 Board Outline & Mounting Holes
Board outline
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6 Certifications
6.1 Declaration of Conformity CE DoC (EU)
We declare under our sole responsibility that the products above are in conformity with the essential requirements
of the following EU Directives and therefore qualify for free movement within markets comprising the European
Union (EU) and European Economic Area (EEA).
ROHS 2 Directive 2011/65/EU
Conforms to: EN50581:2012
Directive 2014/35/EU. (LVD)
EN 60950-
Conforms to:
1:2006/A11:2009/A1:2010/A12:2011/AC:2011
Directive 2004/40/EC & 2008/46/EC & 2013/35/EU,
EMF
Conforms to: EN 62311:2008
6.2 Declaration of Conformity to EU RoHS & REACH 211 01/19/2021
Arduino boards are in compliance with RoHS 2 Directive 2011/65/EU of the European Parliament and RoHS 3
Directive 2015/863/EU of the Council of 4 June 2015 on the restriction of the use of certain hazardous substances in
electrical and electronic equipment.
Substance Maximum limit (ppm)
Lead (Pb) 1000
Cadmium (Cd) 100
Mercury (Hg) 1000
Hexavalent Chromium (Cr6+) 1000
Poly Brominated Biphenyls (PBB) 1000
Poly Brominated Diphenyl ethers (PBDE) 1000
Bis(2-Ethylhexyl} phthalate (DEHP) 1000
Benzyl butyl phthalate (BBP) 1000
Dibutyl phthalate (DBP) 1000
Diisobutyl phthalate (DIBP) 1000
Exemptions: No exemptions are claimed.
Arduino Boards are fully compliant with the related requirements of European Union Regulation (EC) 1907 /2006
concerning the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). We declare none of
the SVHCs (https://echa.europa.eu/web/guest/candidate-list-table), the Candidate List of Substances of Very High
Concern for authorization currently released by ECHA, is present in all products (and also package) in quantities
totaling in a concentration equal or above 0.1%. To the best of our knowledge, we also declare that our products do
not contain any of the substances listed on the "Authorization List" (Annex XIV of the REACH regulations) and
Substances of Very High Concern (SVHC) in any significant amounts as specified by the Annex XVII of Candidate list
published by ECHA (European Chemical Agency) 1907 /2006/EC.
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6.3 Conflict Minerals Declaration
As a global supplier of electronic and electrical components, Arduino is aware of our obligations with regards to
laws and regulations regarding Conflict Minerals, specifically the Dodd-Frank Wall Street Reform and Consumer
Protection Act, Section 1502. Arduino does not directly source or process conflict minerals such as Tin, Tantalum,
Tungsten, or Gold. Conflict minerals are contained in our products in the form of solder, or as a component in
metal alloys. As part of our reasonable due diligence Arduino has contacted component suppliers within our supply
chain to verify their continued compliance with the regulations. Based on the information received thus far we
declare that our products contain Conflict Minerals sourced from conflict-free areas.
7 FCC Caution
Any Changes or modifications not expressly approved by the party responsible for compliance could void the user’s
authority to operate the equipment.
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1) This device may not cause harmful interference
(2) this device must accept any interference received, including interference that may cause undesired operation.
FCC RF Radiation Exposure Statement:
1. This Transmitter must not be co-located or operating in conjunction with any other antenna or transmitter.
2. This equipment complies with RF radiation exposure limits set forth for an uncontrolled environment.
3. This equipment should be installed and operated with minimum distance 20cm between the radiator &
your body.
English: User manuals for license-exempt radio apparatus shall contain the following or equivalent notice in a
conspicuous location in the user manual or alternatively on the device or both. This device complies with Industry
Canada license-exempt RSS standard(s). Operation is subject to the following two conditions:
(1) this device may not cause interference
(2) this device must accept any interference, including interference that may cause undesired operation of the
device.
French: Le présent appareil est conforme aux CNR d’Industrie Canada applicables aux appareils radio exempts de
licence. L’exploitation est autorisée aux deux conditions suivantes :
(1) l’ appareil nedoit pas produire de brouillage
(2) l’utilisateur de l’appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible
d’en compromettre le fonctionnement.
IC SAR Warning:
English This equipment should be installed and operated with minimum distance 20 cm between the radiator and
your body.
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French: Lors de l’ installation et de l’ exploitation de ce dispositif, la distance entre le radiateur et le corps est d ’au
moins 20 cm.
Important: The operating temperature of the EUT can’t exceed 85℃ and shouldn’t be lower than -40℃.
Hereby, Arduino S.r.l. declares that this product is in compliance with essential requirements and other relevant
provisions of Directive 2014/53/EU. This product is allowed to be used in all EU member states.
8 Company Information
Company name Arduino S.r.l
Company Address Via Andrea Appiani 25 20900 MONZA Italy
9 Reference Documentation
Reference Link
Arduino IDE
https://www.arduino.cc/en/Main/Software
(Desktop)
Arduino IDE (Cloud) https://create.arduino.cc/editor
Cloud IDE Getting https://create.arduino.cc/projecthub/Arduino_Genuino/getting-started-with-arduino-web-
Started editor-4b3e4a
Arduino Website https://www.arduino.cc/
Project Hub https://create.arduino.cc/projecthub?by=part&part_id=11332&sort=trending
Library Reference https://www.arduino.cc/reference/en/
Online Store https://store.arduino.cc/
10 Revision History
Date Revision Changes
26/07/2023 2 General Update
06/2021 1 Datasheet release
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