Problems starting debug of F439ZI

[alanb]

Hi,

I sometimes get this error when starting a Debug on an F439ZI

Error in final launch sequence:

Failed to start GDB server

Failed to start GDB server

Error in initializing ST-LINK device.

Reason: (5) Unknown MCU found on target.

Unplugging and replugging the USB to the ST-link fixes it, but it is a bit perplexing. Is there a better way?

[Issamos]

Hello @alanb 

I think that the problem come from the port usb in your PC or the cable you are using.

I suggest you to try to change them.

Best regards.

II

[TDK]

Going into low power modes or changing the function of SWDIO/SWCLK pins can cause debugger connection issues.

Are you using a counterfeit programmer? Is this a custom board?

[alanb]

No, I'm using a genuine Nucleo F439ZI board. But it was connected and powered from a laptop so it is I guess possible that the laptop USB didn't supply enough current. I have added an external power connector to my daughterboard.