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221 lines
9.0 KiB
221 lines
9.0 KiB
/*
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LUFA Library
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Copyright (C) Dean Camera, 2013.
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dean [at] fourwalledcubicle [dot] com
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www.lufa-lib.org
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*/
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/*
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Copyright 2013 Dean Camera (dean [at] fourwalledcubicle [dot] com)
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Permission to use, copy, modify, distribute, and sell this
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software and its documentation for any purpose is hereby granted
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without fee, provided that the above copyright notice appear in
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all copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the name of the author not be used in
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advertising or publicity pertaining to distribution of the
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software without specific, written prior permission.
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The author disclaims all warranties with regard to this
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software, including all implied warranties of merchantability
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and fitness. In no event shall the author be liable for any
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special, indirect or consequential damages or any damages
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whatsoever resulting from loss of use, data or profits, whether
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in an action of contract, negligence or other tortious action,
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arising out of or in connection with the use or performance of
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this software.
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*/
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/** \file
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*
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* USB Device Configuration Descriptor processing routines, to determine the correct pipe configurations
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* needed to communication with an attached USB device. Descriptors are special computer-readable structures
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* which the host requests upon device enumeration, to determine the device's capabilities and functions.
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*/
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#include "ConfigDescriptor.h"
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/** Index of the currently used Audio Streaming Interface within the device. */
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uint8_t StreamingInterfaceIndex = 0;
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/** Alternative Setting of the currently used Audio Streaming Interface within the device. */
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uint8_t StreamingInterfaceAltSetting = 0;
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/** Address of the streaming audio endpoint currently in use within the device. */
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uint8_t StreamingEndpointAddress = 0;
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/** Reads and processes an attached device's descriptors, to determine compatibility and pipe configurations. This
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* routine will read in the entire configuration descriptor, and configure the hosts pipes to correctly communicate
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* with compatible devices.
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*
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* This routine searches for a Streaming Audio interface descriptor containing a valid Isochronous audio endpoint.
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*
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* \return An error code from the \ref AudioHost_GetConfigDescriptorDataCodes_t enum.
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*/
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uint8_t ProcessConfigurationDescriptor(void)
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{
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uint8_t ConfigDescriptorData[512];
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void* CurrConfigLocation = ConfigDescriptorData;
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uint16_t CurrConfigBytesRem;
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USB_Descriptor_Interface_t* AudioControlInterface = NULL;
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USB_Descriptor_Interface_t* AudioStreamingInterface = NULL;
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USB_Descriptor_Endpoint_t* DataOUTEndpoint = NULL;
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/* Retrieve the entire configuration descriptor into the allocated buffer */
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switch (USB_Host_GetDeviceConfigDescriptor(1, &CurrConfigBytesRem, ConfigDescriptorData, sizeof(ConfigDescriptorData)))
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{
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case HOST_GETCONFIG_Successful:
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break;
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case HOST_GETCONFIG_InvalidData:
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return InvalidConfigDataReturned;
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case HOST_GETCONFIG_BuffOverflow:
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return DescriptorTooLarge;
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default:
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return ControlError;
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}
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while (!(DataOUTEndpoint))
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{
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/* See if we've found a likely compatible interface, and if there is an endpoint within that interface */
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if (!(AudioControlInterface) ||
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USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
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DComp_NextAudioInterfaceDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
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{
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/* Check if we haven't found an Audio Control interface yet, or if we have run out of related Audio Streaming interfaces */
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if (!(AudioControlInterface) ||
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USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
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DComp_NextAudioStreamInterface) != DESCRIPTOR_SEARCH_COMP_Found)
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{
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/* Find a new Audio Control interface if the current one doesn't contain a compatible streaming interface */
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if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
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DComp_NextAudioControlInterface) != DESCRIPTOR_SEARCH_COMP_Found)
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{
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/* Descriptor not found, error out */
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return NoCompatibleInterfaceFound;
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}
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/* Save the interface in case we need to refer back to it later */
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AudioControlInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);
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/* Find the next Audio Streaming interface within that Audio Control interface */
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if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
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DComp_NextAudioStreamInterface) != DESCRIPTOR_SEARCH_COMP_Found)
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{
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/* Descriptor not found, error out */
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return NoCompatibleInterfaceFound;
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}
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}
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/* Save the interface in case we need to refer back to it later */
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AudioStreamingInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);
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/* Skip the remainder of the loop as we have not found an endpoint yet */
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continue;
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}
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/* Retrieve the endpoint address from the endpoint descriptor */
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USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Endpoint_t);
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/* Save the endpoint if it is an OUT type endpoint */
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if ((EndpointData->EndpointAddress & ENDPOINT_DIR_MASK) == ENDPOINT_DIR_OUT)
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DataOUTEndpoint = EndpointData;
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}
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StreamingInterfaceIndex = AudioStreamingInterface->InterfaceNumber;
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StreamingInterfaceAltSetting = AudioStreamingInterface->AlternateSetting;
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StreamingEndpointAddress = DataOUTEndpoint->EndpointAddress;
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/* Configure the Audio data OUT pipe */
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Pipe_ConfigurePipe(AUDIO_DATA_OUT_PIPE, EP_TYPE_ISOCHRONOUS, DataOUTEndpoint->EndpointAddress, DataOUTEndpoint->EndpointSize, 2);
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/* Valid data found, return success */
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return SuccessfulConfigRead;
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}
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/** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
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* configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
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* descriptor processing if an incompatible descriptor configuration is found.
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*
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* This comparator searches for the next Interface descriptor of the correct Audio Control Class, Subclass and Protocol values.
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*
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* \return A value from the DSEARCH_Return_ErrorCodes_t enum
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*/
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uint8_t DComp_NextAudioControlInterface(void* CurrentDescriptor)
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{
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USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
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if (Header->Type == DTYPE_Interface)
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{
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USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);
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if ((Interface->Class == AUDIO_CSCP_AudioClass) &&
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(Interface->SubClass == AUDIO_CSCP_ControlSubclass) &&
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(Interface->Protocol == AUDIO_CSCP_ControlProtocol))
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{
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return DESCRIPTOR_SEARCH_Found;
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}
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}
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return DESCRIPTOR_SEARCH_NotFound;
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}
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/** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
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* configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
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* descriptor processing if an incompatible descriptor configuration is found.
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*
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* This comparator searches for the next Interface descriptor of the correct Audio Streaming Class, Subclass and Protocol values.
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*
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* \return A value from the DSEARCH_Return_ErrorCodes_t enum
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*/
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uint8_t DComp_NextAudioStreamInterface(void* CurrentDescriptor)
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{
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USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
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if (Header->Type == DTYPE_Interface)
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{
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USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);
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if ((Interface->Class == AUDIO_CSCP_AudioClass) &&
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(Interface->SubClass == AUDIO_CSCP_AudioStreamingSubclass) &&
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(Interface->Protocol == AUDIO_CSCP_StreamingProtocol))
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{
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return DESCRIPTOR_SEARCH_Found;
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}
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}
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return DESCRIPTOR_SEARCH_NotFound;
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}
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/** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
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* configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
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* descriptor processing if an incompatible descriptor configuration is found.
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*
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* This comparator searches for the next Isochronous Endpoint descriptor within the current interface, aborting the
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* search if another interface descriptor is found before the next endpoint.
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*
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* \return A value from the DSEARCH_Return_ErrorCodes_t enum
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*/
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uint8_t DComp_NextAudioInterfaceDataEndpoint(void* CurrentDescriptor)
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{
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USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
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if (Header->Type == DTYPE_Endpoint)
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{
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USB_Descriptor_Endpoint_t* Endpoint = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Endpoint_t);
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if ((Endpoint->Attributes & EP_TYPE_MASK) == EP_TYPE_ISOCHRONOUS)
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return DESCRIPTOR_SEARCH_Found;
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}
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else if (Header->Type == DTYPE_Interface)
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{
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return DESCRIPTOR_SEARCH_Fail;
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}
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return DESCRIPTOR_SEARCH_NotFound;
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}
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