Renesas has introduced the RL78/L23, the latest addition to its long-running RL78 family. These 16-bit MCUs are built for situations where power budgets are tight, cost needs to stay low, and a small set of peripherals can make the difference between a basic design and a capable product. They run at 32 MHz, support segment LCDs, and integrate capacitive touch, features aimed squarely at smart home appliances, consumer IoT, and metering systems.
Why 16-bit Still Has a Place
In a market dominated by 32-bit MCUs, there is still room for smaller devices that do the job efficiently. For appliances such as cooktops, rice cookers, or simple meters, the appeal of a 16-bit device is obvious: low power draw, straightforward design, and a lower bill of materials. The RL78/L23 builds on this idea by improving LCD performance, adding smarter power modes, and integrating functions that might otherwise need extra components.
Power Profile and LCD Control
In active use, the device consumes about 109 μA/MHz, dropping to 0.365 μA in standby, with a wake-up time of just 1 μs. A new LCD reference mode (VL4) cuts display power by roughly 30% compared with earlier RL78 devices. The SNOOZE Mode Sequencer can refresh LCD segments without waking the CPU, which helps extend battery life and reduces system-level power consumption.
The voltage range runs from 1.6 V to 5.5 V, so it can run directly from 5 V rails often found in household appliances, removing the need for a separate regulator.
Features That Matter in the Field
The MCU brings together features that directly support HMI designs: capacitive touch, an on-chip temperature sensor, and an IH timer for precise induction heating control. Reliability is handled through dual-bank flash, which makes it possible to push firmware updates over the air while the system keeps running. That is especially useful in metering, where downtime is costly or impractical.
“The RL78 family has been one of our most successful products, particularly in home appliances,” said Daryl Khoo, Vice President of Embedded Processing at Renesas. “The RL78/L23 builds on that legacy with new features suited for smart home and IoT solutions, helping our customers bring reliable products to market more quickly.”
Tools and Development Support
Renesas offers a prototyping board that works with Arduino IDE, along with capacitive touch evaluation kits and software such as Smart Configurator. The RL78/L23 is also part of Renesas’ Winning Combinations portfolio, which pairs it with other devices in ready-made reference designs to help shorten design cycles.
For engineers looking at small, battery-friendly HMI systems, the RL78/L23 shows why 16-bit MCUs are still worth considering. They are not aimed at high-end processing, but where cost, efficiency, and reliability are the priorities, this new group fits naturally.
Learn more and read the original article on www.renesas.com
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