What harms STM32

[Maprex]

Hey everybody. I had 3 STM32 F401RE for my robotic project but now I got "no stlink detected" error. Once I turned my computer off with shot down and then on again I couldn't get stm32 to work again, that's why one of them went away, the other one was when I turned the driver on and off while the stm32 was connected to the stepper motor driver and then it went away, i don't remember the other one. My first question is are these stm32s completely broken, can i save them? My second question is if they are completely gone, how can i save my next purchases?

[Peter BENSCH]

What tool is giving this error?
What ST-LINK are you using?
Can you share a photo from back and front of the ST-LINK?

Regards
/Peter

[TDK]

If they were working before, and no longer are, probably the hardware is damaged. Most likely this is due to an overvoltage condition. Especially if it's happening repeatedly.

With motor applications, you should pay attention to inductive loads and ensure you have a flyback diode to prevent overvoltage and backpowering.

https://en.wikipedia.org/wiki/Flyback_diode

[Maprex]

Helle Peter, I am using normal STM32 F401RE and the ST-LINK comes embedded in Nucleo Board. When I jumped in the CubeIDE it gives the error