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Description

Add a Mixer Unit to the specified class instance (i.e. audio function).

Files

usbd_audio.h / usbd_audio.c

Prototype

Arguments

class_nbr

Class instance number.

p_mu_cfg

Pointer to the Mixer Unit configuration structure.

p_mu_api

Pointer to the audio codec API associated to this Mixer Unit.

p_err

Pointer to variable that will receive the return error code from this function.

USBD_ERR_NONE 
USBD_ERR_CLASS_INVALID_NBR
USBD_ERR_NULL_PTR 
USBD_ERR_AUDIO_MU_ALLOC
USBD_ERR_ALLOC

Returned Value

Unit ID assigned by audio class, if NO error(s).

0, otherwise

Callers

Application.

Notes / Warnings

  1. This function is enabled by setting the configuration constant USBD_AUDIO_CFG_MAX_NBR_MU to a value different from zero.

  2. Audio 1.0 specification indicates that ID #0 is reserved for undefined ID. Thus it indicates an error.

  3. p_mu_api can be DEF_NULL if the Mixer Unit does NOT support any programmable controls. 
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