Arduino chooses 32bit Renesas Coretex-M4 for new Uno

Arduino chooses 32bit Renesas Coretex-M4 for new Uno

Scheduled to appear in late May, Uno R4 will come in two versions: the plain ‘Uno R4 Minima’, and ‘Uno R4 WiFi’ with an Espressif S3 WiFi module that also gives it Bluetooth Low Energy. “We collaborated with Renesas and Espressif,” said Arduino CEO Fabio Violante.

Arduino chooses 32bit Renesas Coretex-M4 for new Uno

This partly obscured photo is the only one Arduino has allowed out so far

“Designed for maximum compatibility, the Uno R4 maintains the same form factor, shield compatibility, and 5V operating voltage as its predecessor,” said Arduino.

The Cortex-M4 runs at 48MHz alongside 32kbyte of ram and 256kbyte of flash. Peripherals include CAN bus, an SPI port and a 12bit DAC. There is also 8kbyte of data flash.

Power can now be supplied at up to 24V, an the main board interface is now USB-C.


For backwards compatibility with existing code examples and tutorials, “significant efforts are being made on the software side. Popular Arduino libraries are being optimised”, said Arduino. “Most existing libraries and examples will work seamlessly on the new board. Support for other Renesas microcontrollers, such as the RL78/G22 and G23, has also been added to the Arduino IDE.”

Arduino chooses 32bit Renesas Coretex-M4 for new UnoRenesas RA4M1 super-set block diagram. 48pin versions do not miss out on many major peripherals, except the LCD segment driver, serial sound interface and asynchronous timers

Some libraries that are optimised for the AVR architecture used in the original Arduinos, such as the Uno R3, may need to be ported to the Renesas architecture. Arduino intends to provide a public list of such libraries, with links to alternatives.

To aid library developers in porting low-level code to the Renesas architecture, there is and early-adopter program (scroll down here).

Arduino Uno 4 web page

Arduino Uno 4 availability updates

Renesas RA4M1 product page