Back in 2024, Renesas first released the RA0E1, an ultra-low-power Cortex-M23 MCU designed for cost-sensitive applications, followed by the RA0E2, with extended temperature range support (-40°C to +125°C). The company has expanded its lineup with the RA0E3, a stripped-down version of the RA0E1 with less memory, fewer peripherals, and fewer GPIOs, designed for small and budget-focused applications for sensing, motor assist, safety, and basic system control.
The MCU retains the same 32 MHz Arm Cortex-M23 (Armv8-M) core but now comes with 16KB flash and 2KB SRAM. It features an 8-channel 16-bit TAU timer, a 32-bit interval timer, a 10-bit ADC with a temperature sensor, a Data Transfer Controller, and serial interfaces including SPI, I²C, and UART (with LIN support). Additionally, it comes with up to 17 GPIOs, pull-ups, open-drain support, and built-in clock sources. It has an operating voltage range of 1.6V to 5.5V and supports −40°C to +125°C operation in a 20-pin TSSOP package.
Renesas RA0E3 Series specifications:
- MCU Core – Arm Cortex-M23 (Armv8-M architecture) clocked at up to 32 MHz
- Memory and Storage
- 2KB SRAM
- 16KB code flash
- Flash read protection (FRP)
- Peripherals
- Serial
- 1x Serial Array Unit (SAU) with 4x Simplified SPI, Simplified I2C, or UART with LIN-bus support
- 1x I2C bus interface (IICA)
- Up to 17x General Purpose I/O pins (5V tolerance, open drain, input pull-up)
- Analog
- 10-bit A/D Converter (ADC10) with up to 6 channels
- Integrated Temperature Sensor (TSN)
- Timers
- 8x 16-bit Timer Array Unit (TAU) (7x PWM outputs)
- 1x 32-bit interval timer (TML32) configurable as 1x 32-bit, 2x 16-bit, or 4x 8-bit counters
- Serial
- Clock Sources
- 32 MHz high-speed on-chip oscillator (HOCO) with ±1% accuracy
- 32.768 kHz low-speed on-chip oscillator (LOCO)
- Clock trim support
- Clock output/buzzer output pin
- Safety and Security
- Flash area protection, 128-bit unique ID
- ADC self-diagnosis function
- Cyclic Redundancy Check (CRC) calculator
- GPIO read-back level detection
- Register write protection
- Illegal memory access detection
- Debugging – CoreSight MTB-M23, SW-DP debug port
- Misc
- Independent watchdog timer
- Data Transfer Controller (DTC)
- Power
- Voltage – 1.6V to 5.5V
- Consumption (Low power modes)
- Active mode – ~ 2.6 mA at 32 MHz
- Software Standby mode – ~0.2 µA (typ.)
- Power-on reset (POR) and Low Voltage Detection (LVD)
- Operating Temperature – -40 °C to +125 °C
- Package – 20-pin TSSOP (4.4 mm × 6.5 mm, 0.65 mm pitch)
The RA0E3 MCU is supported by the Renesas Flexible Software Package (FSP) and various development tools, including e² studio, CS+, and HAL driver code. The FSP provides a hardware abstraction layer (HAL), peripheral drivers, middleware, and example projects to simplify development. The MCU also supports standard CMSIS-based development, debugging through the CoreSight SWD interface, and programming with the Renesas Flash Programmer, allowing developers to integrate the RA0E3 into existing Arm Cortex-M development workflows.
Reneses mentions that the RA0E3 is designed to add low-cost functionality to existing designs without redesigning the main system architecture. An example they mention is food processors or kitchen mixers, where the MCU can handle tasks like a safety lock mechanism. Instead of using a more capable and expensive main processor for these auxiliary functions, the RA0E3 can act as a dedicated sub-microcontroller. The MCU can often be integrated without additional components, such as external oscillators or voltage-level shifters, helping keep the overall BoM cost low.
The company also designed the FPB-RA0E3 (RTK7FPA0E3S00001BJ) fast prototyping board for evaluation and early firmware development. It features an RA0E3 20-pin MCU with 16KB flash and 2KB SRAM, a built-in SEGGER J-Link emulator circuit, through-holes with access to all MCU pins, and Arduino Uno and Pmod interfaces for easy prototyping and expansion.
At the time of writing, only two SKUs appear to be available. One of them, R7FA0E3034ZSD#VA0, is listed on DigiKey at $0.61 per unit, dropping to $0.26607 when ordering in quantities of 5,016+. The development board sells for $12.19 on Digikey. More details, including the datasheet and user manual, can be found on the product page, along with additional information in the official press release.
Debashis Das is a technical content writer and embedded engineer with over five years of experience in the industry. With expertise in Embedded C, PCB Design, and SEO optimization, he effectively blends difficult technical topics with clear communication
Support CNX Software! Donate via cryptocurrencies, become a Patron on Patreon, or purchase goods on Amazon or Aliexpress. We also use affiliate links in articles to earn commissions if you make a purchase after clicking on those links.
