On eBay I found some cheap Arduino boards with STM32 microcontrollers.
They have a Cortex M3 with 72 MHz and 64/28 Kbytes of flash memory.
Do you know it I can use them just like "ordinary" STM32 boards? I mean program them via ST Link? If so, do I have to get rid of the bootloader first?
Do you know it I can use them just like "ordinary" STM32 boards? I mean program them via ST Link?
AFAIK, these are "maple mini" clones. Maybe. They don't have an STLink connector, but it should work if you connect up the correct pins. They may or may not include a USB bootloader, but the STM103 they use has a built-in (ROM) serial bootloader.
The boards that the link points to are not Mini Maple clones. They are known as "blue pill" stm32 boards. They are similar to mini maple but not quite the same. They can also be found on Aliexpress for as cheap as $2 US. Like the Maple, they can be programmed with the Arduino IDE once you configure it properly with the files you download from the website mentioned below. They can also be programmed with the standard STM toolset if you are so inclined.
For using them in the Arduino environment, everything you ever wanted to know about them and more can be found on Roger Clarke's excellent site here: stm32dunio
FWIW, the stm32duino website grew out of a thread on this forum that grew to 175+ pages!
Original STM32 thread