Arduino Announces the 32-Bit UNO R4

During the 10th Arduino Day, Arduino CEO Fabio Violante introduced the Arduino UNO R4. This new 32-bit board is the first significant upgrade to the venerable R3, which has been around since 2010.

The UNO, or technically the UNO R3, form factor is instantly recognizable. Fortunately for shield compatibility, the UNO R4 continues with the same physical form factor. A Renesas RA4M1 32-bit Arm Cortex-M4 microcontroller (MCU) running at 48 MHz powers the R4. In addition, this chip contains 32 kilobytes of SRAM and 256 kilobytes of flash. All of these basic specs are significant upgrades over the previous UNO.

One more feature maintains the hardware compatibility. The RA4M1 runs at 5 volts! So keeping the UNO pinout combined with MCU operating voltage means this new UNO R4 is compatible with existing hardware.

Early Adopter Program

Libraries and examples written entirely in the Arduino language will probably work out of the box. However, changing to an Arm-based 32-bit processor means some software incompatibilities could exist. For example, libraries optimized for a specific processor or architecture may need an update.

To address this issue, Arduino announced the Early Adopter Program. Anyone developing a library for the Arduino UNO can apply to receive an UNO R4 early… for free! Supporting the community in this way means new users should be able to continue to leverage the existing wealth of shields, tutorials, and code developed for the UNO R3.

Open source library developers can apply for the Early Adopter Program from the UNO R4 preview page.

Two Models

There are two Uno R4 models: Minima and WiFi. The Minima is a cost-effective solution if you do not need wireless connectivity, while the UNO R4 WiFi adds an Espressif ESP32-S3 for Bluetooth and Wi-Fi.

Other key features of the UNO R4 include moving to a USB-C port for power and programming. Like the recently announced Giga, the UNO R4 supports 24 volts on Vin. Also, the UNO R4 adds a 12-bit digital-to-analog (DAC) converter.

Arduino says the board will launch in late May 2023. For additional details, check out the Arduino UNO R4 announcement blog post.