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Associate II
August 23, 2025
Solved

USB composite CDC+UVC stops receiving data on EP

  • August 23, 2025
  • 1 reply
  • 516 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

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?

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.Best regards,FBL
Artur5AuthorBest answer
Associate II
August 25, 2025

Hi.

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

BR

Artur