- /** Type define for an Audio class specific interface descriptor. This follows a regular interface descriptor to
- * supply extra information about the audio device's layout to the host. See the USB Audio specification for more
- * details.
- */
- typedef struct
- {
- USB_Descriptor_Header_t Header; /**< Regular descriptor header containing the descriptor's type and length */
- uint8_t Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
-
- uint16_t ACSpecification; /**< Binary coded decimal value, indicating the supported Audio Class specification version */
- uint16_t TotalLength; /**< Total length of the Audio class specific descriptors, including this descriptor */
-
- uint8_t InCollection; /**< Total number of audio class interfaces within this device */
- uint8_t InterfaceNumbers[1]; /**< Interface numbers of each audio interface */
- } USB_Audio_Interface_AC_t;
-
- /** Type define for an Audio class specific Feature Unit descriptor. This indicates to the host what features
- * are present in the device's audio stream for basic control, such as per-channel volume. See the USB Audio
- * specification for more details.
- */
- typedef struct
- {
- USB_Descriptor_Header_t Header; /**< Regular descriptor header containing the descriptor's type and length */
- uint8_t Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
-
- uint8_t UnitID; /**< ID value of this feature unit - must be a unique value within the device */
- uint8_t SourceID; /**< Source ID value of the audio source input into this feature unit */
-
- uint8_t ControlSize; /**< Size of each element in the ChanelControlls array */
- uint8_t ChannelControls[3]; /**< Feature masks for the control channel, and each separate audio channel */
-
- uint8_t FeatureUnitStrIndex; /**< Index of a string descriptor describing this descriptor within the device */
- } USB_Audio_FeatureUnit_t;
-
- /** Type define for an Audio class specific input terminal descriptor. This indicates to the host that the device
- * contains an input audio source, either from a physical terminal on the device, or a logical terminal (for example,
- * a USB endpoint). See the USB Audio specification for more details.
- */
- typedef struct
- {
- USB_Descriptor_Header_t Header; /**< Regular descriptor header containing the descriptor's type and length */
- uint8_t Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
-
- uint8_t TerminalID; /**< ID value of this terminal unit - must be a unique value within the device */
- uint16_t TerminalType; /**< Type of terminal, a TERMINAL_* mask */
- uint8_t AssociatedOutputTerminal; /**< ID of associated output terminal, for physically grouped terminals
- * such as the speaker and microphone of a phone handset
- */
- uint8_t TotalChannels; /**< Total number of separate audio channels within this interface (right, left, etc.) */
- uint16_t ChannelConfig; /**< CHANNEL_* masks indicating what channel layout is supported by this terminal */
-
- uint8_t ChannelStrIndex; /**< Index of a string descriptor describing this channel within the device */
- uint8_t TerminalStrIndex; /**< Index of a string descriptor describing this descriptor within the device */
- } USB_Audio_InputTerminal_t;
-
- /** Type define for an Audio class specific output terminal descriptor. This indicates to the host that the device
- * contains an output audio sink, either to a physical terminal on the device, or a logical terminal (for example,
- * a USB endpoint). See the USB Audio specification for more details.
- */
- typedef struct
- {
- USB_Descriptor_Header_t Header; /**< Regular descriptor header containing the descriptor's type and length */
- uint8_t Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
-
- uint8_t TerminalID; /**< ID value of this terminal unit - must be a unique value within the device */
- uint16_t TerminalType; /**< Type of terminal, a TERMINAL_* mask */
- uint8_t AssociatedInputTerminal; /**< ID of associated input terminal, for physically grouped terminals
- * such as the speaker and microphone of a phone handset
- */
- uint8_t SourceID; /**< ID value of the unit this terminal's audio is sourced from */
-
- uint8_t TerminalStrIndex; /**< Index of a string descriptor describing this descriptor within the device */
- } USB_Audio_OutputTerminal_t;
-
- /** Type define for an Audio class specific streaming interface descriptor. This indicates to the host
- * how audio streams within the device are formatted. See the USB Audio specification for more details.
- */
- typedef struct
- {
- USB_Descriptor_Header_t Header; /**< Regular descriptor header containing the descriptor's type and length */
- uint8_t Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
-
- uint8_t TerminalLink; /**< ID value of the output terminal this descriptor is describing */
-
- uint8_t FrameDelay; /**< Delay in frames resulting from the complete sample processing from input to output */
- uint16_t AudioFormat; /**< Format of the audio stream, see Audio Device Formats specification */
- } USB_Audio_Interface_AS_t;
-
- /** Type define for a 24bit audio sample frequency structure. GCC does not contain a built in 24bit datatype,
- * this this structure is used to build up the value instead. Fill this structure with the SAMPLE_FREQ() macro.
- */
- typedef struct
- {
- uint16_t LowWord; /**< Low 16 bits of the 24-bit value */
- uint8_t HighByte; /**< Upper 8 bits of the 24-bit value */
- } Audio_SampleFreq_t;
-
- /** Type define for an Audio class specific audio format descriptor. This is used to give the host full details
- * about the number of channels, the sample resolution, acceptable sample frequencies and encoding method used
- * in the device's audio streams. See the USB Audio specification for more details.