USBD_Audio_CfgAdd

Description

Add an audio class instance into the specified configuration. The audio class instance was previously created by the function USBD_Audio_Add.

Files

usbd_audio.h / usbd_audio.c

Prototype

void  USBD_Audio_CfgAdd (CPU_INT08U   class_nbr,
                         CPU_INT08U   dev_nbr,
                         CPU_INT08U   cfg_nbr,
                         USBD_ERR    *p_err);

Arguments

class_nbr

Class instance number.

dev_nbr

Device number.

cfg_nbr

Configuration index to add audio class instance to.

p_err

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

USBD_ERR_NONE

USBD_ERR_INVALID_ARG

USBD_ERR_ALLOC

USBD_ERR_NULL_PTR

USBD_ERR_DEV_INVALID_NBR

USBD_ERR_DEV_INVALID_STATE

USBD_ERR_CFG_INVALID_NBR

USBD_ERR_IF_ALLOC

USBD_ERR_IF_ALT_ALLOC

USBD_ERR_IF_INVALID_NBR

USBD_ERR_EP_NONE_AVAIL

USBD_ERR_EP_ALLOC

Returned Value

None.

Callers

Application.

Notes / Warnings

If USBD_Audio_CfgAdd() is called several times from the application, it allows to create multiple instances and multiple configurations. For instance, the following architecture could be created:

Audio Class 0 (device number 0)
    |-- Configuration 0
    |-- Configuration 1
Audio Class 1 (device number 1)
    |-- Configuration 0
    |-- Configuration 1
The Configuration Descriptor corresponding to an audio device has the following format:
Configuration Descriptor
|-- Interface Descriptor (AudioControl) [standard]
|-- Header Descriptor [class-specific]
|-- Unit Descriptor(s) [class-specific]
|-- Terminal Descriptor(s) [class-specific]
|-- Endpoint Descriptor (Interrupt IN) - optional [standard]
|-- Interface Descriptor (AudioStreaming) [standard]
|-- AS Interface Descriptor [class-specific]
|-- AS Format Type Descriptor [class-specific]
|-- AS Format-Specific Descriptor(s) [class-specific]
|-- Endpoint Descriptor (Isochronous IN or OUT Data) [standard]
|-- AS Isochronous Audio Data Endpoint Descriptor [class-specific]
|-- Endpoint Descriptor (Isochronous OUT or IN Synch endpoint) [standard]
|-- Interface Descriptor (AudioStreaming) [standard]
|-- ...
|-- Interface Descriptor (AudioStreaming) [standard]
|-- ...

The function USBD_Audio_CfgAdd() only adds the AudioControl interface descriptor. Other standard and class-specific descriptors are added by functions: