Dear Nordic,
I am currently working on a USB project were I am interested in building a USB audio device with two-way volume control, i.e. such that both host and the device can set the volume level. I am trying to base it on your audio_headphone class from the "usbd_audio" example. I have enabled volume control for the feature unit, such that I can send volume levels from host to device. I am however having difficulties sending volume levels from device to host.
Consulting the "USB Device Class Definition for Audio Devices 1.0" Chapter 3.7.1 to 3.7.1.2 I gather that I should add an interrupt endpoint for status returns to the AudioControl Interface, such that I can notify the host that the device status has changed and the volume level should be polled.
My question is therefore: Any suggestions on how I go about expanding your headphones example to support this? I have sadly not have much success de-convoluting your "APP_USBD_AUDIO_GLOBAL_DEF" define, which sets up the Audio class instance.
Best regards,
Taylor
