I need to write a multiple (6 at least) cdc devices with hardware flow control within one STM32F403. The data would be processed, then sent modified via one UART. Examples I found are old and hard to follow for new CubeMx generated code.

[Tesla DeLorean]

You need to write it, or you need someone else to write it? Have you implemented this before on another platform?

Perhaps start be determining the pins and U(S)ARTs you're going to use for this on the part you've already selected.

[Uwe Bonnes]

You will run out of USB endpoint. Each CDCACM needs at least one common and two dedicated endpoints.

[RBera.2]

I have implemented USB CDC device on this platform using CubeMx code generator. Used it to drive stepper motors.

I tried multiplying USB descriptor, but it still just showed up as only one CDC device.

[RBera.2]

I do not need it to pass data on different UARTS, just to be able to receive it in a buffer and distinguish from which endpoint it arrived. The goal is to create multiple wireless RS232 ports with full hardware flow support, so the data would be passed via just one UART to a WiFi device to be redistributed where necessary.

All the data can go to/from the same RX/TX buffer provided I implement a way to distinguish from where it came.

For now I am only trying to get it to register as multiple CDC devices.