Secure, low power, Renesas Arm Cortex-M33 microcontroller

The “RA4M3 Group” was introduced by Renesas Electronics as a new product of the “RA family” Arm core microcomputer and began mass production ( news release ). The “Arm Cortex-M33” that acts as a CPU up to 100MHz is incorporated into the new product. It targets IoT applications such as industrial equipment, equipment for HVAC (Heating Ventilation and Air Conditioning) and meters.

RA4M3 is a subordinate microcomputer product of the “RA6M4 Group”* that incorporates the same CPU cores. The RA6M4 Cortex-M33 will run at 200MHz, the fastest on the market in the RA family. The top speed is 100MHz with this R4M3, which is half the speed, but the power consumption is decreased accordingly. In active mode, the current consumption is 119μA / MHz, which executes the CoreMark algorithm from flash memory. In standby mode, 1.6mA. The standby mode wake-up time is as low as 30 μs, which is said to be “ideal for IoT applications that operate for a long time with intermittent operation” (the company)

The organization claims that its abundant security functions also define the new product. It is compliant with Arm’s “Trust Zone” authentication technology, which is the Cortex-M33 selling point, and also implements the original “Secure Crypto Engine” encryption circuit from Renesas. The Stable Crypto Engine makes several forms of symmetric and asymmetric cryptography simple to accelerate, handle advanced keys, manage the protection life cycle, detect tampering, and maintain resistance to side-channel assaults.

Up to 1 Mbytes of application flash memory, 128 Kbytes of SRAM, 8 Kbytes of data flash memory, and 1 Kbyte of standby SRAM are built into the RA4M3. The flash memory of the program has a dual bank setup and has a swap feature and background operation. This encourages firmware upgrades to be carried out in the background, for instance.

In addition, to boost reliability, SRAM is fitted with parity (error detection) / ECC (error correction) functions. It’s simple to connect additional memory by combining the Quad-SPI and SD card interfaces.


In addition, it can integrate a 12-bit AD converter, a 12-bit DA converter, a capacitive contact sensor unit, etc. The kit (with optional LGA / BGA package) is 64/100/144 pin LQFP. The temperature range for activity is -40 to + 105 ° C. The voltage spectrum for service is 2.7 to 3.6V. With multiple programs, pulses, memory features and packages, there are 7 items. For development, the evaluation kit ‘EK-RA4M3’ is available.