Nuvoton’s New MCU Balances Low Power Consumption and Speed

While the MCU can run at speeds of up to 72 MHz, its processing architecture and ReRAM technology keep power consumption low.

This week, Nuvoton released a new MCU that combines an efficient processing architecture and unique memory technology to strike a balance between performance and efficiency.

The M2L31 MCU. Screenshot used courtesy of Nuvoton

Nuvoton designed the M2L31 MCU to target low-power applications such as industrial automation and consumer peripheral devices.

The M2L31 Finds the Sweet Spot of Performance and Power

The M2L31 leverages the Arm Cortex-M23 core (Armv8-M architecture) to deliver up to 72 MHz of processing power. It integrates a single-cycle, 32-bit multiplier and a 17-cycle, 32-bit hardware divider.

It also features up to 512 Kbytes of ReRAM and up to 168 Kbytes of SRAM. The chip provides robust peripheral support, including up to 8 UARTs, 4 I2C, 4 SPI/I2S, and 2 USCI interfaces. Other built-in functions include advanced analog interfaces such as a 24-channel, 12-bit ADC, 12-bit DACs, and programmable gain amplifiers. Additionally, the chip's security features include execute-only memory (XOM), a secure bootloader, and hardware cryptographic accelerators.

System block diagram of the M2L31 MCU. Image used courtesy of Nuvoton

Nuvoton engineered the M2L31 microcontroller to maximize energy efficiency without compromising performance. It supports a range of low-power modes tailored to different operational needs, including normal power-down, standby power-down, and deep power-down modes. In deep power-down mode, the chip's current consumption is minimized to less than 0.5 μA. Its power efficiency also extends to its active modes, where normal run operation consumes only 60 μA/MHz at 72 MHz, while idle mode drops to 33 μA/MHz. 

The MCU Leverages ReRAM

One of the M2L31 series' unique features is its use of resistive random-access memory (ReRAM). ReRAM is an advanced non-volatile memory (NVM) technology that stores data by changing the resistance state of its memory cells through an external voltage. Unlike traditional Flash memory, which relies on charge storage, ReRAM operates by creating and dissolving conductive filaments within a dielectric material. 

The operating states of a ReRAM cell. Image used courtesy of Weebit Nano

ReRAM offers fast read and write speeds, often comparable to DRAM, but with the non-volatility characteristic of Flash memory. This means that data stored in ReRAM is retained even when the power is turned off. Its low power consumption makes it a strong choice for battery-powered and energy-sensitive applications since it requires less energy per write operation compared to Flash memory.

ReRAM boasts a simplified write process. Unlike Flash memory, which requires a page erase before writing, ReRAM allows direct writing to individual cells. This speeds up the write process, while the lack of a pre-erase step streamlines memory management and increases overall system efficiency.

According to Nuvoton, the M2L31 MCU leverages the advantages of ReRAM to deliver high-performance and energy-efficient memory solutions. The M2L31 series comes in several variants featuring 64 to 512 Kbytes of ReRAM, offering the dual benefits of fast access times and low power consumption.

Support for Vast Embedded Applications

As embedded applications demand greater processing power, modern MCUs face a challenge. They must achieve the processing performance necessary to support edge applications while also keeping power consumption at a minimum.

The M2L31’s combination of advanced performance, ReRAM integration, and efficient power management makes it a versatile solution for industrial automation, consumer devices, and other demanding applications. As the industry continues to grapple with balancing embedded performance with power consumption, new solutions like the M2L31 are a step in the right direction.