USB Device Descriptor Request Failed

[KKado.1]

Dear Customer Support

I'm using the USB CDC class (Virtual COM Port) on STM32H7.

When I unplug and plug the USB cable during comport communication, occasionally, the device manager display shows "Unknown USB device (device descriptor request failed)".

If this happens, it will not recover until the device is turned off and on.

Is there a way to solve this problem?

Best Regards,

[Ons KOOLI]

Hi KKado.1,

You may have a look at the STM32CubeH7 Firmware package under directory: \Projects\$Board_Name$\Applications\USB_Device\CDC_Standalone

or you can share with me your .ioc in order to help you, or report the issue internally if necessary.

Best Regards,

Ons.

[KKado.1]

Dear Ons KOOLI:

Thank you for your quick reply.

I attach two .ioc files.

I have added a USB CDC class to an existing project.

(A) is the .ioc file of the existing project, and (B) is the one with USB function added to it.

I generated the source code in the .ioc file in (B) and merged the diffs into the existing source code in (A).

(A)STM32H_240BGA_07.ioc

(B)CDC_VCP3.ioc

I would appreciate if you can comment on that.

Best Regards,

[Ons KOOLI]

Hi KKado.1,

If I well understand, (A) is your original project and you want to add (B) to it. Is this what you want to do ? You want to add CDC to your existing project which already has a specific functionality ?

What I propose for you is the following:

1. Take a look at the existing project in the FW: \Projects\STM32H743I-EVAL\Applications\USB_Device\CDC_Standalone and try to run it successfully and understand it.
2. Generate the project with STM32CubeMX, since you want to work with, and try to align it with the existing project in the FW to have a properly running project.
3. And finally, add this CDC project and integrate it in the original project you are working in.

I hope this is helpful.

Best Regards,

Ons.

[Ons KOOLI]

Hi KKado.1,

Any updates on this question,

Best Regards,

Ons.