Ultra-low-power MCUs deliver advanced capacitive touch sensing

Renesas Electronics Corp. has expanded its 32-bit RA2 Series microcontrollers (MCUs) with 20 new RA2L1 Group MCUs, increasing the total number of RA devices to 66. Based on the  Arm Cortex-M23 core operating up to 48 MHz, the RA2L1 MCUs with advanced capacitive touch sensing offer low power consumption with flexible power modes for IoT node human machine interface (HMI) applications.

Renesas launched its Renesas Advanced (RA) family of 32-bit Arm Cortex-M MCUs last year, targeting IoT application development. The RA family encompasses the RA2 Series, RA4 Series, RA6 Series and dual-core RA8 series.

The advanced capacitive touch IP in the RA2L1 MCUs provides enhanced operability for a variety of touch and touchless system implementations. Examples cited include support for sensing through acrylic or glass panels more than 10-mm thick, as well as implementation of proximity sensing (hovering) and 3D gestures for hygiene or safety limitations. The RA2L1’s capacitive touch noise tolerance meets the requirements of IEC EN61000-4-3 level 4 (radiated) and EN61000-4-6 level 3 (conducted) to ensure reliable operation with minimal sensing errors.

 The RA2L1 MCUs offer an operating current of 64 μA/MHz and software standby current of 250 nA with less than 5 µs fast wakeup. They use the company’s 110-nm low-power process for active and sleep/standby modes and special power-down modes designed for battery-driven applications. This enables users to minimize power consumption close to the standby levels to extend battery life.

The capacitive touch sensing combined with the ultra-low power make the RA2L1 MCUs suited for home appliance, industrial and building automation, medical and health care, and consumer HMI IoT applications.

In addition, the RA2L1 MCUs come with several integrated features to lower BOM costs, including the capacitive touch sensing, embedded flash memory densities up to 256 KB, SRAM at 32 KB, analog, communications, and timing peripherals. Other features include safety and security functions, including an AES cryptography accelerator, true random number generator (TRNG), and memory protection units that provide the fundamental blocks to develop a secure IoT system.

The RA2L1 family also uses an advanced power and clock gating feature. On-chip peripheral functions include a high precision (1.0%) high-speed oscillator, temperature sensor, and multiple power supply interface ports.

The RA2L1 MCUs are supported by the Flexible Software Package (FSP), which allows re-use of legacy code, and Renesas’ partner ecosystem, which offers out-of-the-box software and hardware building block solutions. The FSP includes FreeRTOS and middleware, offering a premium device-to-cloud option for developers. The RA2L1 MCUs and an evaluation board are available from Renesas’ worldwide distributors.