IMO the price of some Chinese cards based on F401, F411, F407 may give rise to doubts about the provenance of the MCUs:
A full F407VE development board for 6€
On Mouser the MCU alone is 6€ (x100)
A minimal F411 board for 3.41 €
https://www.aliexpress.com/item/4000084631884.html?spm=2114.12010615.8148356.1.58b74d8d7QnJlx
On Mouser the MCU alone is 3.80€ (x100)
It seems that there are clones of several STM32s: F030, F031, F051, F101, F103, F107, F405, F407... Have a look at this chinese page: https://www.sekorm.com/news/91323558.html
"In the semiconductor field, although considerable progress has been made in recent years, the basic fact is that the amount of imported chips has been rising every year, exceeding that of strategic materials such as petroleum, reaching more than US$300 billion. Among them, a large number of high-end chips and equipment and materials still need to be imported in large quantities and are restricted. Under these circumstances, many domestic companies are forced to seek alternatives to domestic ICs. On August 4, the State Council issued the "Notice on Several Policies to Promote the High-quality Development of the Integrated Circuit Industry and Software Industry in the New Era", encouraging key integrated circuit design companies and software companies at the national level, which will surely promote the development of local semiconductors again The climax, the road to localization is imperative."
"As of August 2020, Zhongkexin can provide 4 series of 32-bit ARM processors for mass supply products, which can perfectly replace the corresponding models of STMicroelectronics, and have good software and hardware compatibility."
Does this vendor have official license from ST to produce all these MCUs?
