Audio IN over USB on STM32F4

Question

I try to create a simple USB audio interface with audio IN and OUT on a custom board based on an STM32F412 . The audio OUT (from host to target) is working, also with the help of the CubeMX setup for the audio device usb class. But somehow I can't figure out how the opposite way (from target to host) should work.

I see for audio out, AUDIO_PeriodicTC_FS gets called periodically (every 1ms) with the AUDIO_OUT_TC command. It never gets called with AUDIO_IN_TC . I tried to call HAL_PCD_EP_Transmit with some audio data, but the host doesn't get the input...

The descriptor should be right, at least I see both interfaces (in and out) show up on the host.

Is someone experienced in this or can provide some working examples?

Answer 1

Look here . Used and verified. It works. It may need some deeper modification if your chip doesn't have USB OTG

Answer 2

Ive created a simple USB headset on my stm32f4 discovery board. You can check it out, if you're interested:

https://github.com/ancher-bohdan/stm32_usb_interface

It is far from ideal, but it can play music from host and send recorded sound from analog mic to host