Arduino UNO R4

Arduino has released an official successor to the iconic Arduino UNO R3 board, the most well-known representative of the microcontroller platform and programming environment based on Arduino’s open hardware, has been released. The Arduino UNO R4 is the first major update to the venerable Arduino UNO R3, which has been around since 2010 and has over ten million users.

UNO R4 continues with the same physical form factor and 5 volt signal levels. This means that the new UNO R4 is compatible with existing hardware. Arduino says that most of the existing Arduino-language software libraries should work without modification, but some that are optimized for the AVR may need to be modified.

The biggest change id that Arduino UNO R4 replaces the 8-bit Atmel ATMega328 processor used in the R3 version with a modern 32-bit solution based on Reneasa’s ARM core. The UNO R4 features a 32-bit Renesas RA4M1 Cortex®-M4 processor, which significantly increases processing power, memory and functionality. The Renesas RA4M1 32-bit Arm Cortex-M4 microcontroller (MCU) operates at a 48 MHz clock frequency, so it offers significantly more power than the previous version’s 16 MHz processor. There is also more memory (32 kilobytes of SRAM and 256 kilobytes of flash memory).

The card connections have improved. In response to community feedback, the USB port is now a modern USB-C. In addition, the maximum voltage of the card’s power supply has been increased to 24 V with improved thermal design. In addition, the card offers a 12-bit DA converter, CAN bus support and an SPI port as new features. The built-in ADC in the new chip is has 14 bits resolution.

Arduino UNO R4 comes available at the end of May in two versions, named UNO R4 WiFi and UNO R4 Minima. In the WiFi version (suitable for IoT applications), wireless communication is handled by the Espressif S3 WiFi module in addition to the RA4M1. The UNO R4 Minima has just RA4M1 controller and no wireless communications. The new UNO R4 version will not replace the current R3 version completely and the current UNO R3 version will also be available after release of R4.

Links to more information:

Arduino UNO R4 is a giant leap forward for an open source community of millions


  1. Tomi Engdahl says:

    NEW Arduino UNO Rev4 Board! #newdimensionofmaking, #UNOR4

    00:00 Introduction
    00:32 Unboxing
    00:56 Why the R4?
    01:24 Minima & Wifi
    01:42 What’s the Difference? (Specs)
    02:28 Pins
    03:22 What’s the Same?
    03:47 Footprint
    04:12 Take Aways

  2. Tomi Engdahl says:

    “Overall, the R4 WiFi represents such a significant step forward compared to the venerable R3 that it’s easy to recommend it as a first board for the current generation of makers.”

    Make: Magazine reviews our newly launched 32-bit UNO!

    Reviewed: Arduino UNO R4 WiFi

  3. Tomi Engdahl says:

    Somehow impressive that R3 version cost more than the new R4s

  4. Tomi Engdahl says:

    The wait is over. After being announced back on Arduino Day, the revolutionary 32-bit UNO R4 is now available in two variants: UNO R4 Minima and UNO R4 WiFi! Order yours today and get ready to enter a whole new dimension of making:

  5. Tomi Engdahl says:

    Arduino UNO R4: Nice upgrade or troublemaker?

    After 12 years, the UNO R3 is finally getting an update in the form of two new UNO boards, the Arduino UNO R4 Minima and the Arduino UNO R4 WiFi (that’s how Arduino spells it even if the correct spelling should be hyphenated).

    As an educator working with students ranging from teenagers to 60 years old, I had to order the new boards as soon as they were available to see how the new versions will fit in my classrooms.

    I’ve been using the R3 (and its clones) for several years with total beginners, so that’s the focus of my review: How will they fit in a beginner environment ? What might happen when a total noob starts looking for tutorials? How many migraines will I get because of weird edge cases that newcomers are sometime better at finding than more advanced users ?

    The (ugly) code I wrote for my example are here:

  6. Tomi Engdahl says:

    A simple version of Space Invaders on the new UNO R4 WiFi’s LED matrix!

  7. Tomi Engdahl says:

    The Arm version of David Johnson-Davies’ uLisp now adds support for the new Arduino UNO R4:

  8. Miranda says:

    The Arduino UNO R4 Minima is the first UNO board to have a Renesas RA4M1 32-bit microprocessor. It is quicker, has more memory, Drift Boss and has features such as a DAC, RTC, and HID. The UNO R4 Minima is a 5 V board only.


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