Renesas' In-House RISC-V Microcontroller Core Hits the Market as the 48MHz Low-Power R9A02G021 MCU

Its first 32-bit microcontroller to feature an in-house RISC-V core, the R9A02G021 ushers in a new future for Renesas.

Gareth Halfacree
28 days agoHW101

Renesas has announced the first general-purpose 32-bit microcontroller family to be built around its in-house RISC-V processor core, the R9A02G021 range — building atop its previous application-specific designs and targeting power-sensitive and cost-conscious designs.

"From our RISC-V purpose built ASSPs [Application-Specific Standard Products] to this new general-purpose MCU [Microcontroller Unit], our goal is to deliver commercially viable products that customers can take to mass production quickly, while demonstrating the benefits for the RISC-V architecture," claims Renesas' Daryl Khoo.

"In addition, customers often face with complex design challenges and trade-offs such as performance, power consumption, memory, or a choice of CPU architecture. The new RISC-V MCU provides an additional degree of choice to customers who want to use products with the open architecture."

Renesas announced its work on an in-house processor core design built around the free and open-source RISC-V instruction set architecture (ISA) back in November 2023, promising silicon early this year — now revealed as the R9A02G021 family. It wasn't the company's first RISC-V part, though: in March 2023 Renesas launched the R9A06G150, an ASSP designed for edge voice workloads using a bought-in AndesCore D25F RISC-V core.

The R9A02G021, the first using Rensas' own core design, features a single 32-bit processor core running at up to 48MHz and delivering a claimed 3.27 CoreMark per megahertz, has 16kB of static RAM of which 4kB has Error Correcting Code (ECC) support, 128kB of code flash memory, and 4kB of data flash. It includes a 12-bit analog-to-digital converter (ADC) and eight-bit digital to analog converter (DAC), UART, SPI, I2C, and a software-configurable array unit (SAU).

Targeting low-power projects, the microcontrollers draw just 162µA/MHz in active mode and 0.3µA in software standby with a 4µS wakeup time. Support is included in Renesas own e² Studio integrated development environment (IDE), along with the IAR Embedded Workbench IDE and I-jet debug probe and Segger's Embedded Studio IDE and J-Link debug probe. To demonstrate its capabilities, Renesas has also shown off a "Winning Combination" reference design for an all-in-one smart pressure cooker.

"Having developed our own CPU core enables Renesas to optimize the implementation, gives full control of the design choices, and secures the IP roadmap for future products," claims Renesas' Giancarlo Parodi of the benefits from its shift to an in-house core design.

"Renesas has historically deep experience in implementing CPUs for microcontrollers. This provides customer assurance on the deployment of commercially viable products, supported by renowned Renesas quality, and eliminates any concerns about proprietary architectures."

More information on the R9A02G021 parts is available on the Renesas website; pricing starts at $2.70 before volume discounts. The company has also announced the FPB-R9A02G021 RISC-V MCU Fast Prototyping Board for rapid development, priced at $17.29.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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