Japanese electronics company Renesas has introduced a group of 32bit microcontrollers to enable contactless operation of HVAC, smart meters and smart home appliances.

The RX671 MCUs provide touch sensing and voice recognition capabilities for contactless operation.

The Covid-19 pandemic created health and safety requirements that are transforming how people interact with their devices and environments, increasing the demand for hygienic contactless user interfaces. The RX671 is optimised for contactless applications, integrating a capacitive touch sensing unit that combines sensitivity with noise tolerance and can be used to implement contactless proximity switches.

In addition, the serial sound interface can be used to connect digital microphones that support voice recognition over long distances. Used in combination with voice recognition middleware from Renesas’ RX ecosystem partners, these features enable developers to create contactless operation functions using voice recognition in a short amount of time.

Part of the firm’s RX600 series, the MCUs are built around an RXv3 CPU core operating at 120MHz and integrate flash memory supporting fast read access at a clock speed of 60MHz, for real-time performance with a CoreMark score of 707, and power efficiency at 48.8 CoreMark/mA.

Available in various packages with pin counts from 48 to 145 pins with up to 2Mbyte of flash memory and 384kbyte of SRAM, the single-chip devices are suited to applications that require functionality, power efficiency and compact size, such as HVAC, smart meters and smart home appliances.

For size-constrained devices, one version is available with 2Mbyte of flash memory in a 64-pin TFBGA package measuring 4.5 by 4.5mm.

“I am delighted to announce the RX671, which offers the RXv3 CPU core and new functions while maintaining compatibility with the RX651, currently the most popular MCUs in the RX family,” said Sakae Ito, vice president at Renesas. “RX671will meet the needs of a wide range of customers with its combination of real-time performance, power efficiency, HMI functions, security functions and many package options.”

The RX671 integrates Renesas’ Trusted Secure IP as a part of its built-in hardware security engine, which comprises an encryption engine with AES, RSA, ECC and SHA support, a true random number generator, and an encrypted key management mechanism. Combining these with the dual-bank function and protection function of the on-chip flash memory allows users to implement capabilities such as secure firmware updates and secure boot.

Renesas has also introduced two evaluation boards. A target board makes it easier to evaluate the RX671 without the need for a separate debugger; the Starter Kit+ for RX671 supports detailed evaluation of the MCU’s main functions. Both boards are equipped with connectors to the Wifi Pmod expansion board for evaluation using wireless network connectivity. The combination of the two boards is Free RTOS-certified, allowing users to obtain certified sample programmes from GitHub and try out using the RX671 in coordination with AWS.

Renesas has combined the MCUs with its complementary power devices to create a complete touchless button offering, which can be used to implement hygienic proximity switches on all kinds of devices to prevent viruses or dirt from adhering to the user’s fingers.

The MCUs are available in 64-, 100- and 144-pin LFQFP packages; mass production of the 48-pin HWQFN, 64-pin TFBGA, 100-pin TFLGA and 145-pin TFLGA package products is scheduled to start early next year.