A few year ago, we covered GigaDevice GD32 MCU based on STM32 Arm Cortex-M3 microcontroller, but with some improvements to the flash and overall performance. So the MCU is not exactly an STM32 clone per se, but it’s pin-to-pin and software compatible.
Now based on a discussion on STM32duino forum, it looks like another company (CKS – 中科芯微) may have made an actual clone of STM32 with CS32, more exactly CS32F103 that is compatible with STM32F103.
CS32 comes with an Arm Cortex-M3 core clocked at 72 MHz, 64 to 128KB flash, and 20 KB RAM. A datasheet and user manual are available but only in Chinese. Several STM32duino members suspect it’s an actual copy of STM32 without modifications. What’s unclear is whether it’s a pirated copy, or a properly licensed one.
CS32F103C8T6 & CS32F103CBT6 parts can be purchased on Aliexpress for $0.80 shipped and up. The datasheet mentions 64KB or 128KB, but some people tested CS32F103C8T6 and confirmed it to have 128KB flash.
The STM32 clones are also making their way into the popular Bluepill development board, as some sellers have already replaced STM32 with CS32, and are selling the CS32 “Bluepill” board with CS32F103C8T6 MCU for $1.48 shipped.
Thanks to Zoobab for the tip.