WeAct RA4M1 – A small board with plenty of GPIOs that’s software-compatible with the Arduino UNO R4

Last week, we covered the Maker Go RA4M1-R4 development board, an inexpensive “clone” of the Arduino UNO R4 Minima with some small modifications like support for up to 50V DC input and a 3.3V/5V switch for I/Os. But today, I’ve come across a smaller and cheaper Renesas RA4M1 board that’s also software compatible with the Arduino UNO R4. Meet the WeAct RA4M1.

The WeAct RA4M1 is mostly a breakout board for the Renesas R7FA4M1AB3CFM Arm Cortex-M4F microcontroller with two 30-pin GPIO headers, a USB-C port for power and programming, and three buttons. It offers a middle ground between the Arduino UNO R4 Minima and the tiny XIAO RA4M1 USB-C board.

WeAct RA4M1 specifications:

• Microcontroller – Renesas RA4M1 Arm Cortex-M4F MCU @ 48 MHz with 32KB SRAM, 256KB flash
• USB – 1x USB Type-C port for power and programming
• Expansion
  • 2x 30-pin headers with GPIO, VIN, VCC, GND
  • 3.3V or 5V I/O voltage depending on version (also see resistors for 3.3V/5V selection on right side of photo above)
• Debugging – 8-pin SWD/UART 90-degree header
• Misc
  • Reset, MD (bootloader mode), and user (IO13) buttons
  • Power LED, user (IO12) LED
  • 16MHz Crystal
• Power Supply
  • 5V via USB-C port
  • 5V to 12V via Vin pin
• Dimensions – 41.6 x 33.2 mm

Documentation is limited with PDF schematics, “board shape”, 3D STEP file, blink code samples for the Arduino IDE and VS Code (C program), as well as a datasheet and user manual for the RA4M1. But it should not really be an issue since you’ll find plenty of resources on the Renesas and Arduino websites.

The WeAct RA4M1 board can be purchased for $5.85 including shipping if your order is over $10. Note you’ll have to select between the 3.3V IO or 5V IO version. If I change the address to the US, I somehow get a $0.99 “welcome offer” even as a logged-in user, but it’s unclear how this promotion is triggered. The board was launched a few months ago on AliExpress, and some users left feedback and nobody has complained so far…

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