It seems that WeAct will offer a smaller board in "Blue Pill" format as 
well. Found this on GitHub.

Nemopuk wrote:
> Hi all,
>
> The STM32C5 microcontrollers feature an ARM Cortex M33F core with clock
 speeds up to 144 MHz. In addition to the usual ADC and DAC, they also
 include operational amplifiers, comparators, and a delay block. DSP
 instructions, an FPU , and the CORDIC coprocessor enable fast signal
 processing. Three models also include Ethernet. A step-by-step 
debugging approach usually makes it much easier to identify the root 
cause. The same method works well when integrating components like 
KMQ310013M-B419(https://www.jotrin.com/product/parts/KMQ310013M_B419) 
into embedded designs.

 The WeAct STM32C552VET6 100-Pin Core Board is offered on Aliexpress
 starting at €6.

 The STM32C5 series was advertised in 2026 as a low-cost alternative to
 Chinese competitors. It was released alongside a new HAL2 and the new
 Cube MX2. Neither is backward compatible. Arduino does not yet support
 the STM32C5.

> If someone is searching for instructions not using Cube HAL, then my
> private (non commercial) homepage might help:
>
> https://stefanfrings.de/stm32/stm32c5.html
>
> Klick on the "translate" link in the upper right corner below the
> butterfly.
>
> It seems that there is no other website available providing similar
> instructions. The website was written in German, but Google Translator
> does a pretty good job.
>
> P.S.
> If you don't like it, you don't have to read it.

Thanks for sharing this excellent tutorial. It's refreshing to see 
detailed STM32C5 guidance without HAL. Your explanations and effort will 
definitely help beginners and experienced developers exploring this 
microcontroller series.

Thanks for your feedback.