Arduino Uno R4 WiFi

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The Arduino Uno R4 is powered by the Renesas RA4M1 32-bit ARM Cortex-M4 processor, providing a significant boost in processing power, memory, and functionality. The WiFi version comes with an ESP32-S3 WiFi module in addition to the RA4M1, expanding creative opportunities for makers and engineers. The Uno R4 Minima is an affordable option for those who don’t need the additional features.

The Arduino Uno R4 runs at 48 MHz, which provides a 3x increase over the popular Uno R3. Additionally, SRAM has been upgraded from 2 kB to 32 kB, and flash memory from 32 kB to 256 kB to support more complex projects. Responding to community feedback, the USB port is now USB-C, and the maximum power supply voltage has been raised to 24 V with an enhanced thermal design. The board includes a CAN bus and an SPI port, enabling users to reduce wiring and perform parallel tasks by connecting multiple shields. A 12-bit analog DAC is also provided on the board.


Here you will find the technical specifications for the Arduino® UNO R4 WiFi.

Note on ESP header: the ESP32-S3 module on this board operates on 3.3 V. The ESP header located close to the USB-C® connector is 3.3V only and should not be connected to 5 V. This may damage your board.

Note on Qwiic connector: the Qwiic connector on this board is connected to a secondary I2C bus on this board, IIC0. This connector is 3.3 V only, connecting higher voltages may damage your board. To initialize this bus, use Wire1.begin() instead.

Maximum current draw per pin: the UNO R4 series’ maximum current draw per GPIO is 8 mA, which is significantly lower than previous versions. Exceeding this limit may damage your pin / board.

Board Name Arduino® UNO R4 WiFi
SKU ARD-20623
Microcontroller Renesas RA4M1 (Arm® Cortex®-M4)
Radio Module ESP32-S3-MINI-1-N8
USB USB-C® Programming Port
Pins Digital I/O Pins 14
Analog input pins 6
PWM pins 6
External interrupts 2,3
Communication UART Yes, 1x
I2C Yes, 1x
SPI Yes, 1x
CAN Yes 1 CAN Bus
Power Circuit operating voltage 5 V (ESP32-S3 is 3.3 V)
Input voltage (VIN) 6-24 V
DC Current per I/O Pin 8 mA
Clock speed RA4M1 48 MHz
ESP32-S3-MINI-1-N8 up to 240 MHz
Memory RA4M1 256 kB Flash, 32 kB RAM
ESP32-S3-MINI-1-N8 384 kB ROM, 512 kB SRAM
Dimensions Width 68.85 mm
Length 53.34 mm

Arduino Uno R4 WiFi vs. Minima

The Arduino Uno R4 comes in 2 versions (Minima and WiFi) and offers the following new features compared to the Uno R3:

Arduino Uno R4 Minima Arduino Uno R4 WiFi
USB-C connector USB-C connector
RA4M1 from Renesas (Cortex-M4) RA4M1 from Renesas (Cortex-M4)
HID device (emulate a mouse or a keyboard) HID device (emulate a mouse or a keyboard)
Improved power section (up to 24 V through VIN) Improved power section (up to 24 V through VIN)
CAN bus CAN bus
DAC (12 bits) DAC (12 bits)
Op amp Op amp
WiFi/Bluetooth LE
Fully-addressable LED matrix (12×8)
Qwiic I²C connector
RTC (with support for a buffer battery)
Runtime errors diagnostics

Model Comparison

Uno R3 Uno R4 Minima Uno R4 WiFi
Microcontroller Microchip ATmega328P (8-bit AVR RISC) Renesas RA4M1 (32-bit ARM Cortex-M4) Renesas RA4M1 (32-bit ARM Cortex-M4)
Operating Voltage 5 V 5 V 5 V
Input Voltage 6-20 V 6-24 V 6-24 V
Digital I/O Pins 14 14 14
PWM Digital I/O Pins 6 6 6
Analog Input Pins 6 6 6
DC Current per I/O Pin 20 mA 8 mA 8 mA
Clock Speed 16 MHz 48 Mhz 48 Mhz
Flash Memory 32 KB 256 KB 256 KB
SRAM 2 KB 32 KB 32 KB
DAC (12 bit) 1 1
SPI 1 2 2
I²C 1 2 2
CAN 1 1
Op amp 1 1
SWD 1 1
Qwiic I²C connector 1
LED Matrix 12×8 (96 red LEDs)
LED_BUILTIN 13 13 13
Dimensions 68.6 x 53.4 mm 68.9 x 53.4 mm 68.9 x 53.4 mm





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