/*
 * @brief Common definitions and declarations for the library USB Audio 1.0 Class driver
 *
 * @note
 * Copyright(C) NXP Semiconductors, 2012
 * Copyright(C) Dean Camera, 2011, 2012
 * All rights reserved.
 *
 * @par
 * Software that is described herein is for illustrative purposes only
 * which provides customers with programming information regarding the
 * LPC products.  This software is supplied "AS IS" without any warranties of
 * any kind, and NXP Semiconductors and its licensor disclaim any and
 * all warranties, express or implied, including all implied warranties of
 * merchantability, fitness for a particular purpose and non-infringement of
 * intellectual property rights.  NXP Semiconductors assumes no responsibility
 * or liability for the use of the software, conveys no license or rights under any
 * patent, copyright, mask work right, or any other intellectual property rights in
 * or to any products. NXP Semiconductors reserves the right to make changes
 * in the software without notification. NXP Semiconductors also makes no
 * representation or warranty that such application will be suitable for the
 * specified use without further testing or modification.
 *
 * @par
 * Permission to use, copy, modify, and distribute this software and its
 * documentation is hereby granted, under NXP Semiconductors' and its
 * licensor's relevant copyrights in the software, without fee, provided that it
 * is used in conjunction with NXP Semiconductors microcontrollers.  This
 * copyright, permission, and disclaimer notice must appear in all copies of
 * this code.
 */

/** @ingroup Group_USBClassAudio
 *  @defgroup Group_USBClassAudioCommon  Common Class Definitions
 *
 *  @section Sec_ModDescription Module Description
 *  Constants, Types and Enum definitions that are common to both Device and Host modes for the USB
 *  Audio 1.0 Class.
 *
 *  @{
 */

#ifndef _AUDIO_CLASS_COMMON_H_
#define _AUDIO_CLASS_COMMON_H_

	/* Includes: */
		#include "../../Core/StdDescriptors.h"

	/* Enable C linkage for C++ Compilers: */
		#if defined(__cplusplus)
			extern "C" {
		#endif

	/* Preprocessor Checks: */
		#if !defined(__INCLUDE_FROM_AUDIO_DRIVER)
			#error Do not include this file directly. Include LPCUSBlib/Drivers/USB.h instead.
		#endif

	/* Macros: */
		/** @name Audio Channel Masks */
		//@{
		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_LEFT_FRONT           (1 << 0)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_RIGHT_FRONT          (1 << 1)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_CENTER_FRONT         (1 << 2)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_LOW_FREQ_ENHANCE     (1 << 3)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_LEFT_SURROUND        (1 << 4)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_RIGHT_SURROUND       (1 << 5)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_LEFT_OF_CENTER       (1 << 6)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_RIGHT_OF_CENTER      (1 << 7)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_SURROUND             (1 << 8)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_SIDE_LEFT            (1 << 9)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_SIDE_RIGHT           (1 << 10)

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_CHANNEL_TOP                  (1 << 11)
		//@}

		/** @name Audio Feature Masks */
		//@{
		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_MUTE                 (1 << 0)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_VOLUME               (1 << 1)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_BASS                 (1 << 2)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_MID                  (1 << 3)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_TREBLE               (1 << 4)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_GRAPHIC_EQUALIZER    (1 << 5)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_AUTOMATIC_GAIN       (1 << 6)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_DELAY                (1 << 7)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_BASS_BOOST           (1 << 8)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define AUDIO_FEATURE_BASS_LOUDNESS        (1 << 9)
		//@}

		/** @name Audio Terminal Types */
		//@{
		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_UNDEFINED           0x0100

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_STREAMING           0x0101

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_VENDOR              0x01FF

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_IN_UNDEFINED        0x0200

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_IN_MIC              0x0201

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_IN_DESKTOP_MIC      0x0202

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_IN_PERSONAL_MIC     0x0203

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_IN_OMNIDIR_MIC      0x0204

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_IN_MIC_ARRAY        0x0205

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_IN_PROCESSING_MIC   0x0206

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_IN_OUT_UNDEFINED    0x0300

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_OUT_SPEAKER         0x0301

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_OUT_HEADPHONES      0x0302

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_OUT_HEAD_MOUNTED    0x0303

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_OUT_DESKTOP         0x0304

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_OUT_ROOM            0x0305

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_OUT_COMMUNICATION   0x0306

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define AUDIO_TERMINAL_OUT_LOWFREQ         0x0307
		//@}

		/** Convenience macro to fill a 24-bit @ref USB_Audio_SampleFreq_t structure with the given sample rate as a 24-bit number.
		 *
		 *  @param freq  Required audio sampling frequency in HZ
		 */
		#define AUDIO_SAMPLE_FREQ(freq)           {.Byte1 = ((uint32_t)freq & 0xFF), .Byte2 = (((uint32_t)freq >> 8) & 0xFF), .Byte3 = (((uint32_t)freq >> 16) & 0xFF)}

		/** Mask for the attributes parameter of an Audio class-specific Endpoint descriptor, indicating that the endpoint
		 *  accepts only filled endpoint packets of audio samples.
		 */
		#define AUDIO_EP_FULL_PACKETS_ONLY        (1 << 7)

		/** Mask for the attributes parameter of an Audio class-specific Endpoint descriptor, indicating that the endpoint
		 *  will accept partially filled endpoint packets of audio samples.
		 */
		#define AUDIO_EP_ACCEPTS_SMALL_PACKETS    (0 << 7)

		/** Mask for the attributes parameter of an Audio class-specific Endpoint descriptor, indicating that the endpoint
		 *  allows for sampling frequency adjustments to be made via control requests directed at the endpoint.
		 */
		#define AUDIO_EP_SAMPLE_FREQ_CONTROL      (1 << 0)

		/** Mask for the attributes parameter of an Audio class-specific Endpoint descriptor, indicating that the endpoint
		 *  allows for pitch adjustments to be made via control requests directed at the endpoint.
		 */
		#define AUDIO_EP_PITCH_CONTROL            (1 << 1)
		
	/* Enums: */
		/** Enum for possible Class, Subclass and Protocol values of device and interface descriptors relating to the Audio
		 *  device class.
		 */
		enum Audio_Descriptor_ClassSubclassProtocol_t
		{
			AUDIO_CSCP_AudioClass                     = 0x01, /**< Descriptor Class value indicating that the device or
			                                                   *   interface belongs to the USB Audio 1.0 class.
			                                                   */
			AUDIO_CSCP_ControlSubclass                = 0x01, /**< Descriptor Subclass value indicating that the device or
			                                                   *   interface belongs to the Audio Control subclass.
			                                                   */
			AUDIO_CSCP_ControlProtocol                = 0x00, /**< Descriptor Protocol value indicating that the device or
			                                                   *   interface belongs to the Audio Control protocol.
			                                                   */
			AUDIO_CSCP_AudioStreamingSubclass         = 0x02, /**< Descriptor Subclass value indicating that the device or
			                                                   *   interface belongs to the MIDI Streaming subclass.
			                                                   */
			AUDIO_CSCP_MIDIStreamingSubclass          = 0x03, /**< Descriptor Subclass value indicating that the device or
			                                                   *   interface belongs to the Audio streaming subclass.
			                                                   */
			AUDIO_CSCP_StreamingProtocol              = 0x00, /**< Descriptor Protocol value indicating that the device or
			                                                   *   interface belongs to the Streaming Audio protocol.
			                                                   */
		};
	
		/** Audio class specific interface description subtypes, for the Audio Control interface. */
		enum Audio_CSInterface_AC_SubTypes_t
		{
			AUDIO_DSUBTYPE_CSInterface_Header         = 0x01, /**< Audio class specific control interface header. */
			AUDIO_DSUBTYPE_CSInterface_InputTerminal  = 0x02, /**< Audio class specific control interface Input Terminal. */
			AUDIO_DSUBTYPE_CSInterface_OutputTerminal = 0x03, /**< Audio class specific control interface Output Terminal. */
			AUDIO_DSUBTYPE_CSInterface_Mixer          = 0x04, /**< Audio class specific control interface Mixer Unit. */
			AUDIO_DSUBTYPE_CSInterface_Selector       = 0x05, /**< Audio class specific control interface Selector Unit. */
			AUDIO_DSUBTYPE_CSInterface_Feature        = 0x06, /**< Audio class specific control interface Feature Unit. */
			AUDIO_DSUBTYPE_CSInterface_Processing     = 0x07, /**< Audio class specific control interface Processing Unit. */
			AUDIO_DSUBTYPE_CSInterface_Extension      = 0x08, /**< Audio class specific control interface Extension Unit. */
		};

		/** Audio class specific interface description subtypes, for the Audio Streaming interface. */
		enum Audio_CSInterface_AS_SubTypes_t
		{
			AUDIO_DSUBTYPE_CSInterface_General        = 0x01, /**< Audio class specific streaming interface general descriptor. */
			AUDIO_DSUBTYPE_CSInterface_FormatType     = 0x02, /**< Audio class specific streaming interface format type descriptor. */
			AUDIO_DSUBTYPE_CSInterface_FormatSpecific = 0x03, /**< Audio class specific streaming interface format information descriptor. */
		};

		/** Audio class specific endpoint description subtypes, for the Audio Streaming interface. */
		enum Audio_CSEndpoint_SubTypes_t
		{
			AUDIO_DSUBTYPE_CSEndpoint_General         = 0x01, /**< Audio class specific endpoint general descriptor. */
		};

		/** Enum for the Audio class specific control requests that can be issued by the USB bus host. */
		enum Audio_ClassRequests_t
		{
			AUDIO_REQ_SetCurrent    = 0x01, /**< Audio class-specific request to set the current value of a parameter within the device. */
			AUDIO_REQ_SetMinimum    = 0x02, /**< Audio class-specific request to set the minimum value of a parameter within the device. */
			AUDIO_REQ_SetMaximum    = 0x03, /**< Audio class-specific request to set the maximum value of a parameter within the device. */
			AUDIO_REQ_SetResolution = 0x04, /**< Audio class-specific request to set the resolution value of a parameter within the device. */
			AUDIO_REQ_SetMemory     = 0x05, /**< Audio class-specific request to set the memory value of a parameter within the device. */
			AUDIO_REQ_GetCurrent    = 0x81, /**< Audio class-specific request to get the current value of a parameter within the device. */
			AUDIO_REQ_GetMinimum    = 0x82, /**< Audio class-specific request to get the minimum value of a parameter within the device. */
			AUDIO_REQ_GetMaximum    = 0x83, /**< Audio class-specific request to get the maximum value of a parameter within the device. */
			AUDIO_REQ_GetResolution = 0x84, /**< Audio class-specific request to get the resolution value of a parameter within the device. */
			AUDIO_REQ_GetMemory     = 0x85, /**< Audio class-specific request to get the memory value of a parameter within the device. */
			AUDIO_REQ_GetStatus     = 0xFF, /**< Audio class-specific request to get the device status. */
		};
		
		/** Enum for Audio class specific Endpoint control modifiers which can be set and retrieved by a USB host, if the corresponding
		 *  endpoint control is indicated to be supported in the Endpoint's Audio-class specific endpoint descriptor.
		 */
		enum Audio_EndpointControls_t
		{
			AUDIO_EPCONTROL_SamplingFreq = 0x01, /**< Sampling frequency adjustment of the endpoint. */
			AUDIO_EPCONTROL_Pitch        = 0x02, /**< Pitch adjustment of the endpoint. */
		};

	/* Type Defines: */
		/** @brief Audio class-specific Input Terminal Descriptor (nxpUSBlib naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_StdDescriptor_InputTerminal_t for the version of this type with standard element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED 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,
			                                  *   must be @ref AUDIO_DSUBTYPE_CSInterface_InputTerminal.
			                                  */

			uint8_t                 TerminalID; /**< ID value of this terminal unit - must be a unique value within the device. */
			uint16_t                TerminalType; /**< Type of terminal, a \c 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; /**< \c 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. */
		} ATTR_PACKED USB_Audio_Descriptor_InputTerminal_t;

		/** @brief Audio class-specific Input Terminal Descriptor (USB-IF naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_Descriptor_InputTerminal_t for the version of this type with non-standard nxpUSBlib specific
		 *       element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			uint8_t  bLength; /**< Size of the descriptor, in bytes. */
			uint8_t  bDescriptorType; /**< Type of the descriptor, either a value in @ref USB_DescriptorTypes_t or a value
			                           *   given by the specific class.
			                           */

			uint8_t  bDescriptorSubtype; /**< Sub type value used to distinguish between audio class-specific descriptors,
			                              *   must be @ref AUDIO_DSUBTYPE_CSInterface_InputTerminal.
			                              */
			uint8_t  bTerminalID; /**< ID value of this terminal unit - must be a unique value within the device. */
			uint16_t wTerminalType; /**< Type of terminal, a \c TERMINAL_* mask. */
			uint8_t  bAssocTerminal; /**< ID of associated output terminal, for physically grouped terminals
			                          *   such as the speaker and microphone of a phone handset.
			                          */
			uint8_t  bNrChannels; /**< Total number of separate audio channels within this interface (right, left, etc.) */
			uint16_t wChannelConfig; /**< \c CHANNEL_* masks indicating what channel layout is supported by this terminal. */

			uint8_t  iChannelNames; /**< Index of a string descriptor describing this channel within the device. */
			uint8_t  iTerminal; /**< Index of a string descriptor describing this descriptor within the device. */
		} ATTR_PACKED USB_Audio_StdDescriptor_InputTerminal_t;

		/** @brief Audio class-specific Output Terminal Descriptor (nxpUSBlib naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_StdDescriptor_OutputTerminal_t for the version of this type with standard element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED 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,
			                                  *   must be @ref AUDIO_DSUBTYPE_CSInterface_OutputTerminal.
			                                  */

			uint8_t                 TerminalID; /**< ID value of this terminal unit - must be a unique value within the device. */
			uint16_t                TerminalType; /**< Type of terminal, a \c 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. */
		} ATTR_PACKED USB_Audio_Descriptor_OutputTerminal_t;

		/** @brief Audio class-specific Output Terminal Descriptor (USB-IF naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_Descriptor_OutputTerminal_t for the version of this type with non-standard nxpUSBlib specific
		 *       element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			uint8_t  bLength; /**< Size of the descriptor, in bytes. */
			uint8_t  bDescriptorType; /**< Sub type value used to distinguish between audio class-specific descriptors,
			                           *   must be @ref AUDIO_DSUBTYPE_CSInterface_OutputTerminal.
			                           */

			uint8_t  bDescriptorSubtype; /**< Sub type value used to distinguish between audio class-specific descriptors,
			                              *   a value from the @ref Audio_CSInterface_AC_SubTypes_t enum.
			                              */
			uint8_t  bTerminalID; /**< ID value of this terminal unit - must be a unique value within the device. */
			uint16_t wTerminalType; /**< Type of terminal, a \c TERMINAL_* mask. */
			uint8_t  bAssocTerminal; /**< ID of associated input terminal, for physically grouped terminals
			                          *   such as the speaker and microphone of a phone handset.
			                          */
			uint8_t  bSourceID; /**< ID value of the unit this terminal's audio is sourced from. */

			uint8_t  iTerminal; /**< Index of a string descriptor describing this descriptor within the device. */
		} ATTR_PACKED USB_Audio_StdDescriptor_OutputTerminal_t;

		/** @brief Audio class-specific Interface Descriptor (nxpUSBlib naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_StdDescriptor_Interface_AC_t for the version of this type with standard element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED 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,
			                                  *   a value from the @ref Audio_CSInterface_AS_SubTypes_t enum.
			                                  */

			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 Streaming interfaces linked to this Audio Control interface (must be 1). */
			uint8_t                 InterfaceNumber; /**< Interface number of the associated Audio Streaming interface. */
		} ATTR_PACKED USB_Audio_Descriptor_Interface_AC_t;

		/** @brief Audio class-specific Interface Descriptor (USB-IF naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_Descriptor_Interface_AC_t for the version of this type with non-standard nxpUSBlib specific
		 *       element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			uint8_t  bLength; /**< Size of the descriptor, in bytes. */
			uint8_t  bDescriptorType; /**< Type of the descriptor, either a value in @ref USB_DescriptorTypes_t or a value
			                           *   given by the specific class.
			                           */

			uint8_t  bDescriptorSubtype;/**< Sub type value used to distinguish between audio class-specific descriptors,
			                             *   a value from the @ref Audio_CSInterface_AS_SubTypes_t enum.
			                             */

			uint16_t bcdADC; /**< Binary coded decimal value, indicating the supported Audio Class specification version. */
			uint16_t wTotalLength; /**< Total length of the Audio class-specific descriptors, including this descriptor. */

			uint8_t  bInCollection; /**< Total number of Audio Streaming interfaces linked to this Audio Control interface (must be 1). */
			uint8_t  bInterfaceNumbers; /**< Interface number of the associated Audio Streaming interface. */
		} ATTR_PACKED USB_Audio_StdDescriptor_Interface_AC_t;

		/** @brief Audio class-specific Feature Unit Descriptor (nxpUSBlib naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_StdDescriptor_FeatureUnit_t for the version of this type with standard element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED 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,
			                                  *   must be @ref AUDIO_DSUBTYPE_CSInterface_Feature.
			                                  */

			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 \c ChannelControls 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. */
		} ATTR_PACKED USB_Audio_Descriptor_FeatureUnit_t;

		/** @brief Audio class-specific Feature Unit Descriptor (USB-IF naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_Descriptor_FeatureUnit_t for the version of this type with non-standard nxpUSBlib specific
		 *       element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			uint8_t bLength; /**< Size of the descriptor, in bytes. */
			uint8_t bDescriptorType; /**< Type of the descriptor, either a value in @ref USB_DescriptorTypes_t or a value
			                          *   given by the specific class.
			                          */

			uint8_t bDescriptorSubtype; /**< Sub type value used to distinguish between audio class-specific descriptors,
			                             *   must be @ref AUDIO_DSUBTYPE_CSInterface_Feature.
			                             */

			uint8_t bUnitID; /**< ID value of this feature unit - must be a unique value within the device. */
			uint8_t bSourceID; /**< Source ID value of the audio source input into this feature unit. */

			uint8_t bControlSize; /**< Size of each element in the \c ChannelControls array. */
			uint8_t bmaControls[3]; /**< Feature masks for the control channel, and each separate audio channel. */

			uint8_t iFeature; /**< Index of a string descriptor describing this descriptor within the device. */
		} ATTR_PACKED USB_Audio_StdDescriptor_FeatureUnit_t;

		/** @brief Audio class-specific Streaming Audio Interface Descriptor (nxpUSBlib naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_StdDescriptor_Interface_AS_t for the version of this type with standard element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED 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,
			                                  *   a value from the @ref Audio_CSInterface_AS_SubTypes_t enum.
			                                  */

			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. */
		} ATTR_PACKED USB_Audio_Descriptor_Interface_AS_t;

		/** @brief Audio class-specific Streaming Audio Interface Descriptor (USB-IF naming conventions).
		 *
		 *  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.
		 *
		 *  @see @ref USB_Audio_Descriptor_Interface_AS_t for the version of this type with non-standard nxpUSBlib specific
		 *       element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			uint8_t  bLength; /**< Size of the descriptor, in bytes. */
			uint8_t  bDescriptorType; /**< Type of the descriptor, either a value in @ref USB_DescriptorTypes_t or a value
			                           *   given by the specific class.
			                           */

			uint8_t  bDescriptorSubtype; /**< Sub type value used to distinguish between audio class-specific descriptors,
			                              *   a value from the @ref Audio_CSInterface_AS_SubTypes_t enum.
			                              */

			uint8_t  bTerminalLink; /**< ID value of the output terminal this descriptor is describing. */

			uint8_t  bDelay; /**< Delay in frames resulting from the complete sample processing from input to output. */
			uint16_t wFormatTag; /**< Format of the audio stream, see Audio Device Formats specification. */
		} ATTR_PACKED USB_Audio_StdDescriptor_Interface_AS_t;

		/** @brief Audio class-specific Format Descriptor (nxpUSBlib naming conventions).
		 *
		 *  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.
		 *
		 *  @note This descriptor <b>must</b> be followed by one or more @ref USB_Audio_SampleFreq_t elements containing
		 *        the continuous or discrete sample frequencies.
		 *
		 *  @see @ref USB_Audio_StdDescriptor_Format_t for the version of this type with standard element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED 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,
			                                  *   must be @ref AUDIO_DSUBTYPE_CSInterface_FormatType.
			                                  */

			uint8_t                 FormatType; /**< Format of the audio stream, see Audio Device Formats specification. */
			uint8_t                 Channels; /**< Total number of discrete channels in the stream. */

			uint8_t                 SubFrameSize; /**< Size in bytes of each channel's sample data in the stream. */
			uint8_t                 BitResolution; /**< Bits of resolution of each channel's samples in the stream. */

			uint8_t                 TotalDiscreteSampleRates; /**< Total number of discrete sample frequencies supported by the device. When
			                                                   *   zero, this must be followed by the lower and upper continuous sampling
			                                                   *   frequencies supported by the device; otherwise, this must be followed
			                                                   *   by the given number of discrete sampling frequencies supported.
			                                                   */
		} ATTR_PACKED USB_Audio_Descriptor_Format_t;

		/** @brief 24-Bit Audio Frequency Structure.
		 *
		 *  Type define for a 24bit audio sample frequency structure. As GCC does not contain a built in 24-bit datatype,
		 *  this this structure is used to build up the value instead. Fill this structure with the @ref AUDIO_SAMPLE_FREQ() macro.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			uint8_t Byte1; /**< Lowest 8 bits of the 24-bit value. */
			uint8_t Byte2; /**< Middle 8 bits of the 24-bit value. */
			uint8_t Byte3; /**< Upper 8 bits of the 24-bit value. */
		} ATTR_PACKED USB_Audio_SampleFreq_t;

		/** @brief Audio class-specific Format Descriptor (USB-IF naming conventions).
		 *
		 *  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.
		 *
		 *  @note This descriptor <b>must</b> be followed by one or more 24-bit integer elements containing the continuous
		 *        or discrete sample frequencies.
		 *
		 *  @see @ref USB_Audio_Descriptor_Format_t for the version of this type with non-standard nxpUSBlib specific
		 *       element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			uint8_t bLength; /**< Size of the descriptor, in bytes. */
			uint8_t bDescriptorType; /**< Sub type value used to distinguish between audio class-specific descriptors,
			                          *   must be @ref AUDIO_DSUBTYPE_CSInterface_FormatType.
			                          */

			uint8_t bDescriptorSubtype;/**< Sub type value used to distinguish between audio class-specific descriptors,
			                            *   a value from the @ref Audio_CSInterface_AS_SubTypes_t enum.
			                            */

			uint8_t bFormatType; /**< Format of the audio stream, see Audio Device Formats specification. */
			uint8_t bNrChannels; /**< Total number of discrete channels in the stream. */

			uint8_t bSubFrameSize; /**< Size in bytes of each channel's sample data in the stream. */
			uint8_t bBitResolution; /**< Bits of resolution of each channel's samples in the stream. */

			uint8_t bSampleFrequencyType; /**< Total number of sample frequencies supported by the device. When
			                               *   zero, this must be followed by the lower and upper continuous sampling
			                               *   frequencies supported by the device; otherwise, this must be followed
			                               *   by the given number of discrete sampling frequencies supported.
			                               */
		} ATTR_PACKED USB_Audio_StdDescriptor_Format_t;

		/** @brief Audio class-specific Streaming Endpoint Descriptor (nxpUSBlib naming conventions).
		 *
		 *  Type define for an Audio class-specific endpoint descriptor. This contains a regular endpoint
		 *  descriptor with a few Audio-class-specific extensions. See the USB Audio specification for more details.
		 *
		 *  @see @ref USB_Audio_StdDescriptor_StreamEndpoint_Std_t for the version of this type with standard element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			USB_Descriptor_Endpoint_t Endpoint; /**< Standard endpoint descriptor describing the audio endpoint. */

			uint8_t                   Refresh; /**< Always set to zero for Audio class devices. */
			uint8_t                   SyncEndpointNumber; /**< Endpoint address to send synchronization information to, if needed (zero otherwise). */
		} ATTR_PACKED USB_Audio_Descriptor_StreamEndpoint_Std_t;

		/** @brief Audio class-specific Streaming Endpoint Descriptor (USB-IF naming conventions).
		 *
		 *  Type define for an Audio class-specific endpoint descriptor. This contains a regular endpoint
		 *  descriptor with a few Audio-class-specific extensions. See the USB Audio specification for more details.
		 *
		 *  @see @ref USB_Audio_Descriptor_StreamEndpoint_Std_t for the version of this type with non-standard nxpUSBlib specific
		 *       element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			uint8_t  bLength; /**< Size of the descriptor, in bytes. */
			uint8_t  bDescriptorType; /**< Type of the descriptor, either a value in @ref USB_DescriptorTypes_t or a
			                           *   value given by the specific class.
			                           */
			uint8_t  bEndpointAddress; /**< Logical address of the endpoint within the device for the current
			                            *   configuration, including direction mask.
			                            */
			uint8_t  bmAttributes; /**< Endpoint attributes, comprised of a mask of the endpoint type (\c EP_TYPE_*)
			                        *   and attributes (\c ENDPOINT_ATTR_*) masks.
			                        */
			uint16_t wMaxPacketSize; /**< Size of the endpoint bank, in bytes. This indicates the maximum packet size
			                          *   that the endpoint can receive at a time.
			                          */
			uint8_t  bInterval; /**< Polling interval in milliseconds for the endpoint if it is an INTERRUPT or
			                     *   ISOCHRONOUS type.
			                     */

			uint8_t  bRefresh; /**< Always set to zero for Audio class devices. */
			uint8_t  bSynchAddress; /**< Endpoint address to send synchronization information to, if needed (zero otherwise). */
		} ATTR_PACKED USB_Audio_StdDescriptor_StreamEndpoint_Std_t;

		/** @brief Audio class-specific Extended Endpoint Descriptor (nxpUSBlib naming conventions).
		 *
		 *  Type define for an Audio class-specific extended endpoint descriptor. This contains extra information
		 *  on the usage of endpoints used to stream audio in and out of the USB Audio device, and follows an Audio
		 *  class-specific extended endpoint descriptor. See the USB Audio specification for more details.
		 *
		 *  @see @ref USB_Audio_StdDescriptor_StreamEndpoint_Spc_t for the version of this type with standard element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED 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,
			                                  *   a value from the @ref Audio_CSEndpoint_SubTypes_t enum.
			                                  */

			uint8_t                 Attributes; /**< Audio class-specific endpoint attributes, such as @ref AUDIO_EP_FULL_PACKETS_ONLY. */

			uint8_t                 LockDelayUnits; /**< Units used for the LockDelay field, see Audio class specification. */
			uint16_t                LockDelay; /**< Time required to internally lock endpoint's internal clock recovery circuitry. */
		} ATTR_PACKED USB_Audio_Descriptor_StreamEndpoint_Spc_t;

		/** @brief Audio class-specific Extended Endpoint Descriptor (USB-IF naming conventions).
		 *
		 *  Type define for an Audio class-specific extended endpoint descriptor. This contains extra information
		 *  on the usage of endpoints used to stream audio in and out of the USB Audio device, and follows an Audio
		 *  class-specific extended endpoint descriptor. See the USB Audio specification for more details.
		 *
		 *  @see @ref USB_Audio_Descriptor_StreamEndpoint_Spc_t for the version of this type with non-standard nxpUSBlib specific
		 *       element names.
		 *
		 *  @note Regardless of CPU architecture, these values should be stored as little endian.
		 */
		typedef ATTR_IAR_PACKED struct
		{
			uint8_t  bLength; /**< Size of the descriptor, in bytes. */
			uint8_t  bDescriptorType; /**< Type of the descriptor, either a value in @ref USB_DescriptorTypes_t or a value
			                           *   given by the specific class.
			                           */

			uint8_t  bDescriptorSubtype; /**< Sub type value used to distinguish between audio class-specific descriptors,
			                              *   a value from the @ref Audio_CSEndpoint_SubTypes_t enum.
			                              */

			uint8_t  bmAttributes; /**< Audio class-specific endpoint attributes, such as @ref AUDIO_EP_FULL_PACKETS_ONLY. */

			uint8_t  bLockDelayUnits; /**< Units used for the LockDelay field, see Audio class specification. */
			uint16_t wLockDelay; /**< Time required to internally lock endpoint's internal clock recovery circuitry. */
		} ATTR_PACKED USB_Audio_StdDescriptor_StreamEndpoint_Spc_t;

	/* Disable C linkage for C++ Compilers: */
		#if defined(__cplusplus)
			}
		#endif
#endif

/** @} */

