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stm32f4 multi instance usb cdc device

Question asked by mennekes.rolf on Feb 3, 2018

For a USB CDC device application I use STM32CubeF4. It works very well now.
Now I need a second CDC channel, which paralel the 1st CDC transmits a data stream to the host.
How do I create a second USB CDC instance with Cube and how is it used?

I have set the parameter "USBD_MAX_NUM_INTERFACES (Maximum number of supported interfaces)" to 2 in Cube, but this has changed nothing in the generated files except for the "#define USBD_MAX_NUM_INTERFACES 2" in usb_conf.h.
USBD_MAX_NUM_INTERFACES is used only once in the file usbd_ctlreq.c throughout the project.

Is this even possible with Cube / HAL or do I have to venture the new adventure and switch to the ARM middleware library?

There is in the description "The USB Component allows multiple instances of the CDC class."
In the STM Cube documentation I did not find any indication that multi instanc CDCe is supported or not.