STlink Getting Frequently Disconnected when Switching MOSFETs

[GladsonT]

I am developing a PMSM motor controller using STM32F103C8T6. I want to check the variables on live expression while I am running the motor. But as soon as I increase the current draw of motor, the values on the live expression starts to show random values or blank fields. and in the console, it prints "Target is not responding, retrying...". Why might this be happening?

I am having this issue on a custom PCB that I have built. I have made a similar PCB with bigger form factor and this issue is slightly lower in that PCB. What could be the causes of this issue? and what precautions should be taken to prevent this?

[GMA]

Hello @GladsonT,

You can try decreasing the used Baudrate to be less parasite sensitive.
Check with a scope DC supply or USART signals to check your power board impact on control board.

[Uwe Bonnes]

Add more ground connections between target and debugger.