WeAct STM32G4 is a tiny board based on STMicro STM32G4 mixed-signal microcontroller

WeAct STM32G4 is a tiny development board based on a 170 MHz STMicro STM32G4 Arm Cortex-M4F mixed-signal microcontroller with DSP instructions and suitable for applications such as motor control, building automation, lighting, digital power meters, and more.

Two versions of the board are offered one with an STM32G474CEU6 “Hi-resolution line” microcontroller equipped with 128KB RAM and 512KB flash, and the other with the lower-end STM32G431CBU6 “Access Line” MCU with just 32KB RAM and 128KB flash. The board also comes with a USB-C port for power and programming, three buttons, and two 24-pin headers.

WeAct STM32G4 specifications:

• Microcontroller (one or the other)
  • STMicro STM32G431CBU6 – Arm Cortex-M4F MCU @ 170 MHz with DSP instructions, 32KB RAM, 128KB flash, and math accelerator
  • STMicro STM32G474CEU6 – Arm Cortex-M4F MCU @ 170 MHz with DSP instructions, 128KB RAM, 512KB flash, and math accelerator; high-resolution timer and complex waveform builder plus event handler (HRTIM) for digital power conversion useful for the design of digital switched-mode power supplies, lighting, welding equipment, solar and wireless charging
• USB – 1x USB Type-C port for power and programming
• Expansion – 2x 24-pin headers with GPIOs, ADC, DAC, I2C, USART, LPUART, OAmp, CAN Bus, timer outputs, etc…
• Debugging – 4-pin SWD header
• Misc
  • Reset and Boot keys, 1x user key
  • Power LED, 1x user LED
• Power Supply
  • 3.3V to 20V DC input via USB-C port (Note: the STM32G4 MCU supports USB PD)
  • MicrOne ME6216A33XG voltage regulator with 3.3V output
• Dimensions – 36.28 x 28.14 mm

Getting started with the board may be somewhat challenging, and the documentation could be worked on. For instance, WeAct Studio did not provide any pinout diagram, so you’d have to look up the pin functions matching the pin names from the schematics or the silkscreen markings with the information from the datasheet or technical reference manual, the good ol’ way…

WeAct Studio does provide the PDF schematics, the STM32G4 datasheet and TRM, some code samples (Blink, ADC, RTC, MSC, SPI flash), and the WeAct Studio Download Tool (Windows only) to flash the firmware via USB or UART. You’ll find those resources on GitHub for both the value line board and the hi-resolution line board, but most people will need to check the tools and documentation on the STMicro website as well.

Besides their tiny size, the other key benefit of those boards is their price as the WeAct STM32G4 board goes for $2.92 and $5.79 for the STM32G431CBU6 and STM32G474CEU6 models respectively, including GPIO and SWD headers, but not shipping that adds about $1 in my case. For reference, the official STMicro NUCLEO-G491RE board is sold for $15.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.

Support CNX Software! Donate via cryptocurrencies, become a Patron on Patreon, or purchase goods on Amazon or Aliexpress