Renesas RA4C1 Arm Cortex-M33 MCU targets Smart Meters and energy-efficient IoT applications

Renasas RA4C1 microcontroller (MCU) group is based on an 80-MHz Arm Cortex M33 core and designed for utility meters and battery-powered IoT applications. It’s especially suited to devices that require advanced security and segment LCD support, such as smart locks, thermostats, building controls, and industrial user interfaces.

The RA4C1 is very similar to the Renesas RA4L1 MCU designed for HMI applications, but it comes with more RAM (96KB vs 64KB), and being optimized for Smart Meters lacks features like capacitive touch and audio output. The new MCU group still comes with up to 512KB code flash, 8KB data flash, plenty of I/Os, and a low-power consumption down to 168 µA/MHz in active mode, and a standby current of less than 1.79 µA with all SRAM retained.

Renesas RA4C1 specifications:

• MCU core – Arm Cortex-M33 Armv8-M core up to 80 MHz
• Memory – 96 KB SRAM
• Storage
  • 256 KB or 512 KB dual-bank code flash
  • 8 KB data flash (100K P/E cycles)
• Human Machine Interface (HMI) – Segment LCD Controller (SLCDC)
• Peripherals
  • 6x Serial Communications Interfaces (SCI)  with I2C, SPI, LIN, and Smart card interface support
  • IrDA interface
  • 2x I2C, 2x UART, 3x SPI, QSPI
  • CAN Bus with Flexible Data-rate (CAN FD)
  • Analog
    • 12-bit ADC
    • Temperature sensor (TSN)
  • Timers
    • 2x 32-bit PWM timers (GPT32)
    • 4x 16-bit PWM timers (GPT16)
    • 2x Low-power AGT timers
    • Watchdog Timer (WDT), Independent WDT (IWDT)
  • 8-channel DMA
  • 5V-tolerant, open-drain, input pull-up GPIOs
• Clock sources
  • Main clock oscillator @ 1 to 20 MHz
  • Sub-clock oscillator @ 32.768 kHz
  • High-speed on-chip oscillator (HOCO) @ 48/64/80 MHz)
  • Middle-speed on-chip oscillator @ 8 MHz
  • Low-speed on-chip oscillator @ 32.768 kHz
  • IWDT-dedicated on-chip oscillator (15 kHz)
  • Clock trim function for HOCO/MOCO/LOCO
  • PLL, PLL_RTC, Clock out support
•  Security
  • Renesas Secure IP (RSIP-E11A)
    • AES, ECC, SHA-224, SHA-256
    • 128-bit unique ID
  • Arm TrustZone – Flash, SRAM, and peripheral security control
  • Device lifecycle management
  • Up to 3x tamper pins
  • Secure pin multiplexing
• Misc
  • RTC
  • Event Link Controller (ELC)
  • Data Transfer Controller (DTC)
• Power Management
  • Supply Voltage – 1.6V to 3.6V
  • Power-on reset
  • Low Voltage Detection (LVD)
  • Low power modes
• Packages – 100-pin LQFP (14×14 mm) or 64-pin LQFP (10×10 mm), both 0.5mm pitch
• Operating Temperature – -40°C to +125°C

Like all other Renesas microcontrollers, the RA4C1 MCUs are supported by the company’s Flexible Software Package (FSP), providing multiple RTOS, BSP, peripheral drivers, middleware, connectivity, networking, and TrustZone support, as well as reference software to build edge AI, motor control, and cloud solutions. The company also explains that the FSP eases the migration of existing IP to and from either RA6 or RA2 Series devices.

Renesas offers the EK-RA4C1 evaluation kit to quickly get started with development. It is equipped with a 100-pin R7FA4C1BD3CFP MCU with 512KB flash, 96KB SRAM, and provides access to GPIO through three 26-pin headers (unpopulated), Pmod connectors, Arduino Uno R3 headers, MikroBUS, and Grove connectors. The board also features a Segment LCD board interface, pins for current measurements, a 32MB octo-SPI flash, a CAN FD interface, and a SEGGER J-Link on-board programmer and debugger, as well as various buttons and LEDs.  The EK-RA4C1 board ships with a segment LCD board, two USB cables, and mounting hardware.

Renesas also released the Smart 1-Ph E-Meter “Winning Combination”, essentially a smart meter reference design, combining the new RA4C1 Group MCU with an RL78/I1B(I1C) MCU with a 24-bit ΔΣ A/D Converter, and an RL78/G1H Sub-GHz wireless microcontroller with support for proprietary frequency shift keying (FSK) or Wi-SUN protocols, as well as a PLC modem IC and line drivers compliant with G3-PLC and PRIME specifications. The design appears to be initially based on a Renesas RA6M1 microcontroller, and can now be updated with a lower-cost RA4C1 MCU.

Renesas RA4C1 MCUs are supposed to be available now, but I could only find price information for one LQFP-100 part (R7FA4C1BD3CFP#UA0) whose sample price is $10.85 on Mouser, dropping to $5.30 per piece for 1K+ orders. The Renesas RA4C1 Evaluation Board can be purchased for $65.37 from various distributors. The product page has more details and software/hardware documentation, and the press release may have additional information.

Thanks to TLS for the tip.

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