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Visitor II
August 23, 2025
Solved

USB composite CDC+UVC stops receiving data on EP

  • August 23, 2025
  • 1 reply
  • 515 views

Hi

I created a composite USB device with CDC and UVC classes using usbd. The device is detected, camera image streaming works, and data transfer via CDC (virtual serial port) also works. However, after a random time, communication on the CDC data out endpoint stops. Reopening this endpoint solves the problem. The same thing happens with EP0. When I repeatedly open and close the serial port, EP0 stops receiving data after some time. If I stop video streaming, CDC communication is stable.Sometimes I also get an incorrect video frame when data is transmitted via CDC. I'm using FreeRTOS, but running everything in a single thread didn't solve the problem. I have no further ideas what could be wrong.Any ideas?

Artur

    This topic has been closed for replies.
    Best answer by Artur5

    Hi.

    Thanks for your interest. I found the problem. Incorrect FIFO configuration.

    BR

    Artur

    1 reply

    Technical Moderator
    August 25, 2025

    Hi @Artur5 

    Would you share minimum firmware to reproduce the issue?

    Artur5AuthorAnswer
    Visitor II
    August 25, 2025

    Hi.

    Thanks for your interest. I found the problem. Incorrect FIFO configuration.

    BR

    Artur