Renesas RA0L1 low-cost Cortex-M23 MCUs adds capacitive, EMI-resistant touch

Renesas has expanded its low-cost RA0 series of low-cost, low-power Cortex-M23 MCUs with the new RA0L1, the first in the lineup to feature integrated capacitive touch. Designed for low-cost battery-powered applications with responsive touch control, ultra-low current consumption, and fast wake-up.

The RA0L1 combines up to 64KB flash, 16KB SRAM, and a 1.6V–5.5V operating range with peripherals such as a 12-bit ADC, temperature sensor, multiple UART/I2C/SPI interfaces, timers, RTC, and a random number generator. It supports up to 24 capacitive touch channels using Renesas’ self-capacitance technology, a high-accuracy ±1% on-chip oscillator, safety functions, and security features including TRNG and unique ID.

Renesas RA0L1 MCU specifications:

• MCU Core – Arm Cortex-M23 Armv8-M Core up to 32MHz
• Memory and Storage
  • 16KB SRAM with parity
  • Code Flash – Up to 64KB
  • Data Flash – 1KB(1M program/erase cycles)
  • Flash read protection (FRP)
  • 128-bit unique ID
• Human-Machine Interface
  • Capacitive Touch Sensing Unit – up to 24 channels
  • Controlled Current Drive Port(CCD) – up to 8
• Peripherals
  • Serial
    • Serial Array Unit (SAU): up to 5× simplified SPI, 6× simplified I²C, 2× UART, 1× UART with LIN support
    • UARTA × 2
    • I²C Bus (IICA) × 2
  • Up to 44 GPIOs (depending on package, 5V tolerant, open-drain, pull-ups)
  • Analog
    • 12-bit ADC (up to 13 channels)
    • On-chip temperature sensor and Internal reference voltage
  • Timers
    • 16-bit Timer Array Unit (TAU) × 8 channels
    • 32-bit Interval Timer (configurable as 2×16-bit or 4×8-bit)
    • Real-Time Clock (RTC) with calendar, alarms, and 1 Hz output
    • PWM output (up to 7 pins)
  • Clock Sources
    • Main clock oscillator (MOSC) 1 to 20 MHz
    • Sub-clock oscillator (SOSC) (32.768 kHz)
    • High-speed on-chip oscillator (HOCO) (24/32 MHz)
    • Middle-speed on-chip oscillator (MOCO) (4 MHz)
    • Low-speed on-chip oscillator (LOCO) (32.768 kHz)
    • Clock trim function for HOCO/MOCO/LOCO
    • Clock out support
• Safety features
  • SRAM parity check
  • Invalid memory access detection
  • Frequency detection
  • A/D test function
  • Output level detection
  • CRC calculator
  • Register write protection
• Security features
  • 128-bit Unique ID
  • True Random Number Generator (TRNG)
  • Flash access window
  • Flash read protection
• Misc
  • Data Transfer Controller (DTC)
  • Event Link Controller (ELC)
  • Power-on reset
  • Low-voltage detection
  • Low power modes
  • Realtime Clock (RTC)
•  Power
  • Voltage – 1.6V to 5.5V
  • Consumption (Low power modes)
    • Active mode: ~2.9 mA
    • Sleep mode: ~0.92 mA
    • Software Standby mode: 0.25 µA
  • Power-on reset, low voltage detection
• Operating Temperature – -40 °C to +105 °C / -40 °C to +125 °C (depending on part)
• Packages
  • 48-pin LFQFP (7×7 mm, 0.5 mm pitch)
  • 48-pin HWQFN (7×7 mm, 0.5 mm pitch)
  • 32-pin LQFP (7×7 mm, 0.8 mm pitch)
  • 32-pin HWQFN (5×5 mm, 0.5 mm pitch)
  • 24-pin HWQFN (4×4 mm, 0.5 mm pitch)
  • 20-pin LSSOP (4.4×6.5 mm, 0.65 mm pitch)

The RA0L1 MCU family consumes only ~2.9 mA in active mode, ~0.92 mA in sleep mode, and goes as low as 0.25 µA in software standby mode. A high-precision on-chip oscillator (HOCO) provides fast wake-up capability, allowing the device to remain in standby for extended periods and reducing overall current consumption by up to 90% compared to conventional solutions.

The RA0L1 is supported by the Renesas Flexible Software Package (FSP), which provides CMSIS-compliant drivers, peripheral HALs, RTOS integration, and middleware for capacitive touch, communication stacks, and security functions. The device is fully supported in the e² studio IDE with GCC and IAR compiler toolchains, and also integrates with Arm Keil MDK. Additionally, Renesas QE tools can be used for touch and smart configurator for peripheral setup, along with support for FreeRTOS and other embedded operating systems.

The company also designed the FPB-RA0L1 fast prototyping board and RSSK-RA0L1 capacitive touch evaluation board. The FPB-RA0L1 integrates a 48-pin RA0L1 MCU (R7FA0L1074CFL) with an on-board SEGGER J-Link emulator,  through-hole pins, Arduino Uno and Pmod interfaces, and two capacitive touch buttons for HMI evaluation in a compact 56mm x 93mm form factor.

The RSSK-RA0L1 is built around the same RA0L1 MCU with a built-in J-Link emulator, and QE for Capacitive Touch software for GUI-based sensitivity tuning, automatic code generation, and prototyping of touch interfaces such as buttons, sliders, and wheels. It works like an evaluation kit and a reference design for touch-enabled systems.

From the product options page, I see there are a total of 68 MCUs in the series, where the R7FA0L1073CFL is the most powerful and features-rich one with 64KB flash, 16KB SRAM, and a 48-pin package, which costs $2.30 on DigiKey for a single quantity and price drops to $1.16 for a quantity of 5,000. The R7FA0E1073CSC is the least powerful one with 32KB flash, 16KB SRAM, and a compact 20-pin package, but no price is available at this stage. The FPB-RA0L1 development board is available on Mouser for $15.34.

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