Arduino Uno Rev3 - image 1
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Arduino·Dev Board

Arduino Uno Rev3

The original Arduino UNO — the world's most popular development board with ATmega328P at 16MHz, 32KB flash, 2KB SRAM, 14 digital I/O (6 PWM), 6 analog inputs, USB-B, and 5V operation. The gateway to electronics and programming for millions.

Starting from

$26.50

Compatible Firmware

Specifications

ArchitectureAVR
CPU Cores1
Clock Speed16MHz
Flash32KB
GPIO Level5V
AntennaNo
StorageNo
Dimensions68.6 × 53.4mm
Weight25g

Components

Microchip ATmega328P 8-bit AVR at 16MHz with 32KB flash, 2KB SRAM, 1KB EEPROM, 6 ADC channels, and 6 PWM outputs in removable DIP-28 package.

Bus Interfaces

SPI
SS: D10SCK: D13MISO: D12MOSI: D11
I2C
SCL: A5SDA: A4
UART
RX: D0TX: D1

GPIO Map

D0
UART RX
digital-inputdigital-output
UART
D1
UART TX
digital-inputdigital-output
UART
D2
Digital I/O / INT0
digital-inputdigital-output
D3
PWM / INT1
digital-inputdigital-outputpwm
PWM
D4
Digital I/O
digital-inputdigital-output
D5
PWM
digital-inputdigital-outputpwm
PWM
D6
PWM
digital-inputdigital-outputpwm
PWM
D7
Digital I/O
digital-inputdigital-output
D8
Digital I/O
digital-inputdigital-output
D9
PWM
digital-inputdigital-outputpwm
PWM
D10
PWM / SPI SS
digital-inputdigital-outputpwm
SPI
D11
PWM / SPI MOSI
digital-inputdigital-outputpwm
SPI
D12
SPI MISO
digital-inputdigital-output
SPI
D13
SPI SCK / LED
digital-inputdigital-output
SPI
A0
Analog Input
digital-inputdigital-outputadc
ADC
A1
Analog Input
digital-inputdigital-outputadc
ADC
A2
Analog Input
digital-inputdigital-outputadc
ADC
A3
Analog Input
digital-inputdigital-outputadc
ADC
A4
I2C SDA / Analog
digital-inputdigital-outputadc
I2C
A5
I2C SCL / Analog
digital-inputdigital-outputadc
I2C

Overview

The Arduino Uno Rev3 is the quintessential microcontroller board that introduced millions to electronics and programming. Based on the ATmega328P running at 16MHz with 32KB flash and 2KB SRAM, it defined the Arduino form factor, pinout, and shield ecosystem that remains the standard today.

With 14 digital I/O pins (6 PWM-capable), 6 analog inputs, a 16MHz crystal oscillator, USB-B connection, power jack (7-12V), ICSP header, and reset button, the UNO provides everything needed to get started. Its DIP-package ATmega328P can be removed and replaced, making it forgiving for beginners who might damage the chip.

Despite being superseded by the R4 series, the Uno Rev3 remains in active production and is the most documented, most supported, and most widely-used Arduino board ever made. Virtually every Arduino tutorial, library, and shield was designed for or tested on the UNO, making it the safest choice for learning and maximum compatibility.

Use Cases

2

Resources

Where to Buy

Explore more of the directory — popular use cases, firmware, and specs to browse next.