Arduino announces the Uno R4 with a 32-bit ARM CPU


Yesterday Arduino CEO Fabio Violante announced the Arduino Uno R4:

It uses the same form factor as the original ATmega328P-based Arduino Uno (R3), so it will take the same shields. However, it’s based on a Renesas RA4M1 ARM microcontroller running at 48 MHz, with 32 Kbytes of SRAM and 256 Kbytes of flash. Unusually for ARM processors the RA4M1 has 5V I/O pins, which will make it compatible with existing Uno hardware and is perhaps the reason for Arduino choosing this relatively unknown chip.

The RA4M1 is based on an ARM Cortex-M4 core, and with a maximum clock of 48MHz it should be similar in performance to the ATSAMD21 boards. From the photograph the board appears to be based on the 64-pin LQFP variant of the processor, which provides 18 14-bit analogue inputs, one 12-bit DAC output, and three op-amps. It will be interesting to see how the op-amps can be used; perhaps they’ll allow a microphone to be connected directly to an analogue input.

There will be two models of the Arduino Uno R4: Minima and WiFi. The Minima is the lowest cost option, while the Uno R4 WiFi adds an Espressif ESP32-S3 for Bluetooth and Wi-Fi. The board is planned to be available in late May 2023.

At the right price it should be a great board for running uLisp, and I hope to have a version running shortly after the boards are available.