Renesas Targets Smart Home Interfaces with the Ultra-Low-Power 16-bit RL78/L23 Microcontroller

Renesas has announced a new ultra-low-power microcontroller targeting human-machine interfaces in smart home devices: the RL78/L23.

"The Renesas RL78 family of 16-bit microcontrollers has been one of the most successful products since its launch more than 10 years ago, particularly in home appliances," claimed Renesas' vice-president of embedded processing Daryl Khoo of the family into which the new model launches. "I'm pleased to announce the RL78/L23, a new generation of RL78 microcontrollers with rich features, ideally suited for smart home appliances and cost-sensitive IoT [Internet of Things] solutions. With these devices, we aim to provide a better user experience with our intuitive development environment so that customers can get to production faster with confidence, based on market-proven Renesas technologies."

The RL78/L23 has a single 16-bit RL78 microcontroller core running at up to 32MHz, up to 32kB of static RAM (SRAM) and 8kB of data flash plus up to 512kB of dual-bank flash targeting safe over-the-air (OTA) firmware updates. As the specifications may suggest, it's not designed to be a speed demon: the RL78/L23 is optimized for low-power ,with a claimed active current draw of 109µA/MHz and a standby current of 0.365µA with a 1µs wake-up time.

Elsewhere on the chip is a segment LCD controller, which is again optimized for power — with Rensas claiming a reduction in LCD operating current of around 30 per cent compared to the RL78/L1x family, thanks to an offload engine dubbed the Snooze Mode Sequencer (SMS) that can keep the LCD segment display active without waking the CPU. There's a capacitive touch input, an IH timer for three-channel induction heat control, and support for operating voltages of 1.6–5.5VDC and operating temperatures of -40–105°C (-40–221°F).

As is tradition for the company's product launches, Renesas is offering a "Winning Combination" reference design which combines the new RL78/L23 with other parts from the company's catalog to build an induction-based rice cooker — using the microcontroller to drive both the heating block itself and the human-machine interface.

More information on the RL78/L23 is available on the Renesas website; the company has also announced a Fast Prototyping Board with segment LCD panel, and a Capacitive Touch Evaluation System.