How to implement composite USB profile on STM32WB5mmg?

[nitinh]

Hello,

I am trying to implement two CDC profile on STM32WB55xx controller. Since it has 8 endpoints, theoretically it should be possible. What should be the approach to achieve this?

[FBL]

Hello @nitinh 

To support dual CDC class in single device, you have to add IAD (Interface Association Descriptor) to extend existing configuration descriptor. Then assign unique endpoints and update class handler to manage 2 CDC instances... Implement callback to handle data reception for CDC profiles. You can manage line coding control request ... and test each CDC profile independently with each UART instance.

[nitinh]

Thank you for the response. Do you have an example of this?

[FBL]

Hi  @nitinh 

Currently we don't have a ready to use example developed by ST. You can check on GitHub similar examples.

[Erlkoenig]

Hi @nitinh ,

I have an example for STM32F103 with three CDC profiles. It uses C++ to generated the IAD's.

[nitinh]

Thanks, I'll check it out. I tried adding IADs and modified device descriptor to composite. After that it showed up on Windows Device Manager as two serial devices but I was not able to communicate over them. Also, the manufacturer was shown Microsoft instead of STMicroelctronics. 

[Erlkoenig]

Are you sure you defined the correct endpoints in the descriptor and use them correctly in your firmware? You can check using wireshark that the descriptor is correct, and that data is sent do the correct endpoint.

[nitinh]

I'll try and update.

[FBL]

Hi @nitinh 

Check How to implement a dual CDC ACM USB device using t... - STMicroelectronics Community