MPU as USB VPC doesn't show up at all anymore.

[GFahl]

I have a Nucleo-144 STM32L4R5ZIT6 board and successfully created a project that sends data over USB as a virtual com port. After a few more modifications and tests the device does not show up anymore on linux (I have not tested it with windows). Reverting back to the known functioning version of my project did not help.

Is there a way for test the MPU to figure out whether it is broken and if so what?

[Pavel A.]

> Is there a way for test the MPU to figure out whether it is broken

Build from scratch and run some examples for needed functionality (USB) on your board. If they won't work, your board likely is the culprit.

-- pa

[Olivier GALLIEN]

Did you try to reinstall ST-Link driver on your Linux system ?

Olivier

[GFahl]

Update:

I tried it out using Windows and got either the error message "Invalid Device Descriptor" or "Device Descriptor Request Failed" in the Windows Device Manager.

After trying out many things I got it to work again. Having the ST-Link plugged in for debugging and as power supply and the MPU USB connector plugged into the same computer. Unplugging the USB connection for the MPU will cause the ST-Link to loose connection to the target. Plugging the MPU USB back in will result in one of the error messages mentioned before. Afterwards unplugging both and plugging both back in will work fine.

> Did you try to reinstall ST-Link driver on your Linux system ?

As far as I know there are no drivers required for Linux systems.