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USB Audio device class on NUCLEO-F446RE

Question asked by Benjamin Brammer on Jun 4, 2017
Latest reply on Jun 6, 2017 by Benjamin Brammer

Hi Guys,

I want to experiment a bit with the USB middleware features from the CubeMX Software. My goal is to output audio from my computer via the NUCLEO board (recognized as an audio device class) and the integrated DAC or via I2S. Sadly I am not checking how this is going to work. I tried to read a lot of application notes (UM1734 on audio class, AM4711 as an example for the SMT32F0 and of course the reference manual) but I don't understand how this is going to work  or what I have to do to make it work.


In UM1734 it is said that I only need the USBD_AUDIO_DataIn() and USBD_AUDIO_DataOut() functions to handle the data transfers. So as I understand the buffer are already implemented right in the USBD_AUDIO_HandleTypeDef , right? So how do I manage to stream the data out to the DAC or I2S? Is there an interrupt generated each time a frame is received from USB (OTG_FS_IRQHandler)? And shall the DAC be triggered after the first received data from USB or - I don't know - after half the buffer size? Does the rest of the USB handle itself or do I have to implement more functions for data reception? As I understood it right only rudimental interface functions are implemented.

I would really appreciate some help here .


best regards