USBAudio.cpp

00001 /* Copyright (c) 2010-2011 mbed.org, MIT License
00002 *
00003 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
00004 * and associated documentation files (the "Software"), to deal in the Software without
00005 * restriction, including without limitation the rights to use, copy, modify, merge, publish,
00006 * distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
00007 * Software is furnished to do so, subject to the following conditions:
00008 *
00009 * The above copyright notice and this permission notice shall be included in all copies or
00010 * substantial portions of the Software.
00011 *
00012 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
00013 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00014 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
00015 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00016 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00017 */
00018 
00019 #include "stdint.h"
00020 #include "USBAudio.h"
00021 #include "USBAudio_Types.h"
00022 
00023 
00024 
00025 USBAudio::USBAudio( uint32_t frequency_in, uint8_t channel_nb_in, uint32_t frequency_out, uint8_t channel_nb_out, uint16_t vendor_id, uint16_t product_id, uint16_t product_release ): USBDevice( vendor_id, product_id, product_release )
00026 {
00027     mute = 0;
00028     volCur = 0x0080;
00029     volMin = 0x0000;
00030     volMax = 0x0100;
00031     volRes = 0x0004;
00032     available = false;
00033     FREQ_IN = frequency_in;
00034     FREQ_OUT = frequency_out;
00035     this->channel_nb_in = channel_nb_in;
00036     this->channel_nb_out = channel_nb_out;
00037     // stereo -> *2, mono -> *1
00038     PACKET_SIZE_ISO_IN = ( FREQ_IN / 500 ) * channel_nb_in;
00039     PACKET_SIZE_ISO_OUT = ( FREQ_OUT / 500 ) * channel_nb_out;
00040     // STEREO -> left and right
00041     channel_config_in = ( channel_nb_in == 1 ) ? CHANNEL_M : CHANNEL_L + CHANNEL_R;
00042     channel_config_out = ( channel_nb_out == 1 ) ? CHANNEL_M : CHANNEL_L + CHANNEL_R;
00043     SOF_handler = false;
00044     buf_stream_out = NULL;
00045     buf_stream_in = NULL;
00046     interruptOUT = false;
00047     writeIN = false;
00048     interruptIN = false;
00049     available = false;
00050     volume = 0;
00051     // connect the device
00052     USBDevice::connect();
00053 }
00054 
00055 bool USBAudio::read( uint8_t *buf )
00056 {
00057     buf_stream_in = buf;
00058     SOF_handler = false;
00059 
00060     while ( !available || !SOF_handler );
00061 
00062     available = false;
00063     return true;
00064 }
00065 
00066 bool USBAudio::readNB( uint8_t *buf )
00067 {
00068     buf_stream_in = buf;
00069     SOF_handler = false;
00070 
00071     while ( !SOF_handler );
00072 
00073     if ( available )
00074     {
00075         available = false;
00076         buf_stream_in = NULL;
00077         return true;
00078     }
00079 
00080     return false;
00081 }
00082 
00083 bool USBAudio::readWrite( uint8_t *buf_read, uint8_t *buf_write )
00084 {
00085     buf_stream_in = buf_read;
00086     SOF_handler = false;
00087     writeIN = false;
00088 
00089     if ( interruptIN )
00090     {
00091         USBDevice::writeNB( EP3IN, buf_write, PACKET_SIZE_ISO_OUT, PACKET_SIZE_ISO_OUT );
00092     }
00093     else
00094     {
00095         buf_stream_out = buf_write;
00096     }
00097 
00098     while ( !available );
00099 
00100     if ( interruptIN )
00101     {
00102         while ( !writeIN );
00103     }
00104 
00105     while ( !SOF_handler );
00106 
00107     return true;
00108 }
00109 
00110 
00111 bool USBAudio::write( uint8_t *buf )
00112 {
00113     writeIN = false;
00114     SOF_handler = false;
00115 
00116     if ( interruptIN )
00117     {
00118         USBDevice::writeNB( EP3IN, buf, PACKET_SIZE_ISO_OUT, PACKET_SIZE_ISO_OUT );
00119     }
00120     else
00121     {
00122         buf_stream_out = buf;
00123     }
00124 
00125     while ( !SOF_handler );
00126 
00127     if ( interruptIN )
00128     {
00129         while ( !writeIN );
00130     }
00131 
00132     return true;
00133 }
00134 
00135 
00136 float USBAudio::getVolume()
00137 {
00138     return ( mute ) ? 0.0 : volume;
00139 }
00140 
00141 
00142 bool USBAudio::EP3_OUT_callback()
00143 {
00144     uint32_t size = 0;
00145     interruptOUT = true;
00146 
00147     if ( buf_stream_in != NULL )
00148     {
00149         readEP( EP3OUT, ( uint8_t * )buf_stream_in, &size, PACKET_SIZE_ISO_IN );
00150         available = true;
00151         buf_stream_in = NULL;
00152     }
00153 
00154     readStart( EP3OUT, PACKET_SIZE_ISO_IN );
00155     return false;
00156 }
00157 
00158 
00159 bool USBAudio::EP3_IN_callback()
00160 {
00161     interruptIN = true;
00162     writeIN = true;
00163     return true;
00164 }
00165 
00166 
00167 
00168 // Called in ISR context on each start of frame
00169 void USBAudio::SOF( int frameNumber )
00170 {
00171     uint32_t size = 0;
00172 
00173     if ( !interruptOUT )
00174     {
00175         // read the isochronous endpoint
00176         if ( buf_stream_in != NULL )
00177         {
00178             if ( USBDevice::readEP_NB( EP3OUT, ( uint8_t * )buf_stream_in, &size, PACKET_SIZE_ISO_IN ) )
00179             {
00180                 if ( size )
00181                 {
00182                     available = true;
00183                     readStart( EP3OUT, PACKET_SIZE_ISO_IN );
00184                     buf_stream_in = NULL;
00185                 }
00186             }
00187         }
00188     }
00189 
00190     if ( !interruptIN )
00191     {
00192         // write if needed
00193         if ( buf_stream_out != NULL )
00194         {
00195             USBDevice::writeNB( EP3IN, ( uint8_t * )buf_stream_out, PACKET_SIZE_ISO_OUT, PACKET_SIZE_ISO_OUT );
00196             buf_stream_out = NULL;
00197         }
00198     }
00199 
00200     SOF_handler = true;
00201 }
00202 
00203 
00204 // Called in ISR context
00205 // Set configuration. Return false if the configuration is not supported.
00206 bool USBAudio::USBCallback_setConfiguration( uint8_t configuration )
00207 {
00208     if ( configuration != DEFAULT_CONFIGURATION )
00209     {
00210         return false;
00211     }
00212 
00213     // Configure isochronous endpoint
00214     realiseEndpoint( EP3OUT, PACKET_SIZE_ISO_IN, ISOCHRONOUS );
00215     realiseEndpoint( EP3IN, PACKET_SIZE_ISO_OUT, ISOCHRONOUS );
00216     // activate readings on this endpoint
00217     readStart( EP3OUT, PACKET_SIZE_ISO_IN );
00218     return true;
00219 }
00220 
00221 
00222 // Called in ISR context
00223 // Set alternate setting. Return false if the alternate setting is not supported
00224 bool USBAudio::USBCallback_setInterface( uint16_t interface, uint8_t alternate )
00225 {
00226     if ( interface == 0 && alternate == 0 )
00227     {
00228         return true;
00229     }
00230 
00231     if ( interface == 1 && ( alternate == 0 || alternate == 1 ) )
00232     {
00233         return true;
00234     }
00235 
00236     if ( interface == 2 && ( alternate == 0 || alternate == 1 ) )
00237     {
00238         return true;
00239     }
00240 
00241     return false;
00242 }
00243 
00244 
00245 
00246 // Called in ISR context
00247 // Called by USBDevice on Endpoint0 request
00248 // This is used to handle extensions to standard requests and class specific requests.
00249 // Return true if class handles this request
00250 bool USBAudio::USBCallback_request()
00251 {
00252     bool success = false;
00253     CONTROL_TRANSFER *transfer = getTransferPtr();
00254 
00255     // Process class-specific requests
00256     if ( transfer->setup.bmRequestType.Type == CLASS_TYPE )
00257     {
00258         // Feature Unit: Interface = 0, ID = 2
00259         if ( transfer->setup.wIndex == 0x0200 )
00260         {
00261             // Master Channel
00262             if ( ( transfer->setup.wValue & 0xff ) == 0 )
00263             {
00264                 switch ( transfer->setup.wValue >> 8 )
00265                 {
00266                     case MUTE_CONTROL:
00267                         switch ( transfer->setup.bRequest )
00268                         {
00269                             case REQUEST_GET_CUR:
00270                                 transfer->remaining = 1;
00271                                 transfer->ptr = &mute;
00272                                 transfer->direction = DEVICE_TO_HOST;
00273                                 success = true;
00274                                 break;
00275 
00276                             case REQUEST_SET_CUR:
00277                                 transfer->remaining = 1;
00278                                 transfer->notify = true;
00279                                 transfer->direction = HOST_TO_DEVICE;
00280                                 success = true;
00281                                 break;
00282 
00283                             default:
00284                                 break;
00285                         }
00286 
00287                         break;
00288 
00289                     case VOLUME_CONTROL:
00290                         switch ( transfer->setup.bRequest )
00291                         {
00292                             case REQUEST_GET_CUR:
00293                                 transfer->remaining = 2;
00294                                 transfer->ptr = ( uint8_t * )&volCur;
00295                                 transfer->direction = DEVICE_TO_HOST;
00296                                 success = true;
00297                                 break;
00298 
00299                             case REQUEST_GET_MIN:
00300                                 transfer->remaining = 2;
00301                                 transfer->ptr = ( uint8_t * )&volMin;
00302                                 transfer->direction = DEVICE_TO_HOST;
00303                                 success = true;
00304                                 break;
00305 
00306                             case REQUEST_GET_MAX:
00307                                 transfer->remaining = 2;
00308                                 transfer->ptr = ( uint8_t * )&volMax;
00309                                 transfer->direction = DEVICE_TO_HOST;
00310                                 success = true;
00311                                 break;
00312 
00313                             case REQUEST_GET_RES:
00314                                 transfer->remaining = 2;
00315                                 transfer->ptr = ( uint8_t * )&volRes;
00316                                 transfer->direction = DEVICE_TO_HOST;
00317                                 success = true;
00318                                 break;
00319 
00320                             case REQUEST_SET_CUR:
00321                                 transfer->remaining = 2;
00322                                 transfer->notify = true;
00323                                 transfer->direction = HOST_TO_DEVICE;
00324                                 success = true;
00325                                 break;
00326 
00327                             case REQUEST_SET_MIN:
00328                                 transfer->remaining = 2;
00329                                 transfer->notify = true;
00330                                 transfer->direction = HOST_TO_DEVICE;
00331                                 success = true;
00332                                 break;
00333 
00334                             case REQUEST_SET_MAX:
00335                                 transfer->remaining = 2;
00336                                 transfer->notify = true;
00337                                 transfer->direction = HOST_TO_DEVICE;
00338                                 success = true;
00339                                 break;
00340 
00341                             case REQUEST_SET_RES:
00342                                 transfer->remaining = 2;
00343                                 transfer->notify = true;
00344                                 transfer->direction = HOST_TO_DEVICE;
00345                                 success = true;
00346                                 break;
00347                         }
00348 
00349                         break;
00350 
00351                     default:
00352                         break;
00353                 }
00354             }
00355         }
00356     }
00357 
00358     return success;
00359 }
00360 
00361 
00362 // Called in ISR context when a data OUT stage has been performed
00363 void USBAudio::USBCallback_requestCompleted( uint8_t *buf, uint32_t length )
00364 {
00365     if ( ( length == 1 ) || ( length == 2 ) )
00366     {
00367         uint16_t data = ( length == 1 ) ? *buf : *( ( uint16_t * )buf );
00368         CONTROL_TRANSFER *transfer = getTransferPtr();
00369 
00370         switch ( transfer->setup.wValue >> 8 )
00371         {
00372             case MUTE_CONTROL:
00373                 switch ( transfer->setup.bRequest )
00374                 {
00375                     case REQUEST_SET_CUR:
00376                         mute = data & 0xff;
00377                         updateVol.call();
00378                         break;
00379 
00380                     default:
00381                         break;
00382                 }
00383 
00384                 break;
00385 
00386             case VOLUME_CONTROL:
00387                 switch ( transfer->setup.bRequest )
00388                 {
00389                     case REQUEST_SET_CUR:
00390                         volCur = data;
00391                         volume = ( float )volCur / ( float )volMax;
00392                         updateVol.call();
00393                         break;
00394 
00395                     default:
00396                         break;
00397                 }
00398 
00399                 break;
00400 
00401             default:
00402                 break;
00403         }
00404     }
00405 }
00406 
00407 
00408 
00409 #define TOTAL_DESCRIPTOR_LENGTH ((1 * CONFIGURATION_DESCRIPTOR_LENGTH) \
00410                                  + (5 * INTERFACE_DESCRIPTOR_LENGTH) \
00411                                  + (1 * CONTROL_INTERFACE_DESCRIPTOR_LENGTH + 1) \
00412                                  + (2 * INPUT_TERMINAL_DESCRIPTOR_LENGTH) \
00413                                  + (1 * FEATURE_UNIT_DESCRIPTOR_LENGTH) \
00414                                  + (2 * OUTPUT_TERMINAL_DESCRIPTOR_LENGTH) \
00415                                  + (2 * STREAMING_INTERFACE_DESCRIPTOR_LENGTH) \
00416                                  + (2 * FORMAT_TYPE_I_DESCRIPTOR_LENGTH) \
00417                                  + (2 * (ENDPOINT_DESCRIPTOR_LENGTH + 2)) \
00418                                  + (2 * STREAMING_ENDPOINT_DESCRIPTOR_LENGTH) )
00419 
00420 #define TOTAL_CONTROL_INTF_LENGTH    (CONTROL_INTERFACE_DESCRIPTOR_LENGTH + 1 + \
00421                                       2*INPUT_TERMINAL_DESCRIPTOR_LENGTH     + \
00422                                       FEATURE_UNIT_DESCRIPTOR_LENGTH    + \
00423                                       2*OUTPUT_TERMINAL_DESCRIPTOR_LENGTH)
00424 
00425 uint8_t *USBAudio::configurationDesc()
00426 {
00427     static uint8_t configDescriptor[] =
00428     {
00429         // Configuration 1
00430         CONFIGURATION_DESCRIPTOR_LENGTH,        // bLength
00431         CONFIGURATION_DESCRIPTOR,               // bDescriptorType
00432         LSB( TOTAL_DESCRIPTOR_LENGTH ),         // wTotalLength (LSB)
00433         MSB( TOTAL_DESCRIPTOR_LENGTH ),         // wTotalLength (MSB)
00434         0x03,                                   // bNumInterfaces
00435         DEFAULT_CONFIGURATION,                  // bConfigurationValue
00436         0x00,                                   // iConfiguration
00437         0x80,                                   // bmAttributes
00438         50,                                     // bMaxPower
00439 
00440         // Interface 0, Alternate Setting 0, Audio Control
00441         INTERFACE_DESCRIPTOR_LENGTH,            // bLength
00442         INTERFACE_DESCRIPTOR,                   // bDescriptorType
00443         0x00,                                   // bInterfaceNumber
00444         0x00,                                   // bAlternateSetting
00445         0x00,                                   // bNumEndpoints
00446         AUDIO_CLASS,                            // bInterfaceClass
00447         SUBCLASS_AUDIOCONTROL,                  // bInterfaceSubClass
00448         0x00,                                   // bInterfaceProtocol
00449         0x00,                                   // iInterface
00450 
00451 
00452         // Audio Control Interface
00453         CONTROL_INTERFACE_DESCRIPTOR_LENGTH + 1,// bLength
00454         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00455         CONTROL_HEADER,                         // bDescriptorSubtype
00456         LSB( 0x0100 ),                          // bcdADC (LSB)
00457         MSB( 0x0100 ),                          // bcdADC (MSB)
00458         LSB( TOTAL_CONTROL_INTF_LENGTH ),       // wTotalLength
00459         MSB( TOTAL_CONTROL_INTF_LENGTH ),       // wTotalLength
00460         0x02,                                   // bInCollection
00461         0x01,                                   // baInterfaceNr
00462         0x02,                                   // baInterfaceNr
00463 
00464         // Audio Input Terminal (Speaker)
00465         INPUT_TERMINAL_DESCRIPTOR_LENGTH,       // bLength
00466         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00467         CONTROL_INPUT_TERMINAL,                 // bDescriptorSubtype
00468         0x01,                                   // bTerminalID
00469         LSB( TERMINAL_USB_STREAMING ),          // wTerminalType
00470         MSB( TERMINAL_USB_STREAMING ),          // wTerminalType
00471         0x00,                                   // bAssocTerminal
00472         channel_nb_in,                          // bNrChannels
00473         LSB( channel_config_in ),               // wChannelConfig
00474         MSB( channel_config_in ),               // wChannelConfig
00475         0x00,                                   // iChannelNames
00476         0x00,                                   // iTerminal
00477 
00478         // Audio Feature Unit (Speaker)
00479         FEATURE_UNIT_DESCRIPTOR_LENGTH,         // bLength
00480         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00481         CONTROL_FEATURE_UNIT,                   // bDescriptorSubtype
00482         0x02,                                   // bUnitID
00483         0x01,                                   // bSourceID
00484         0x01,                                   // bControlSize
00485         CONTROL_MUTE |
00486         CONTROL_VOLUME,                         // bmaControls(0)
00487         0x00,                                   // bmaControls(1)
00488         0x00,                                   // iTerminal
00489 
00490         // Audio Output Terminal (Speaker)
00491         OUTPUT_TERMINAL_DESCRIPTOR_LENGTH,      // bLength
00492         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00493         CONTROL_OUTPUT_TERMINAL,                // bDescriptorSubtype
00494         0x03,                                   // bTerminalID
00495         LSB( TERMINAL_SPEAKER ),                // wTerminalType
00496         MSB( TERMINAL_SPEAKER ),                // wTerminalType
00497         0x00,                                   // bAssocTerminal
00498         0x02,                                   // bSourceID
00499         0x00,                                   // iTerminal
00500 
00501 
00502         // Audio Input Terminal (Microphone)
00503         INPUT_TERMINAL_DESCRIPTOR_LENGTH,       // bLength
00504         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00505         CONTROL_INPUT_TERMINAL,                 // bDescriptorSubtype
00506         0x04,                                   // bTerminalID
00507         LSB( TERMINAL_MICROPHONE ),             // wTerminalType
00508         MSB( TERMINAL_MICROPHONE ),             // wTerminalType
00509         0x00,                                   // bAssocTerminal
00510         channel_nb_out,                         // bNrChannels
00511         LSB( channel_config_out ),              // wChannelConfig
00512         MSB( channel_config_out ),              // wChannelConfig
00513         0x00,                                   // iChannelNames
00514         0x00,                                   // iTerminal
00515 
00516         // Audio Output Terminal (Microphone)
00517         OUTPUT_TERMINAL_DESCRIPTOR_LENGTH,      // bLength
00518         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00519         CONTROL_OUTPUT_TERMINAL,                // bDescriptorSubtype
00520         0x05,                                   // bTerminalID
00521         LSB( TERMINAL_USB_STREAMING ),          // wTerminalType
00522         MSB( TERMINAL_USB_STREAMING ),          // wTerminalType
00523         0x00,                                   // bAssocTerminal
00524         0x04,                                   // bSourceID
00525         0x00,                                   // iTerminal
00526 
00527 
00528 
00529 
00530 
00531 
00532         // Interface 1, Alternate Setting 0, Audio Streaming - Zero Bandwith
00533         INTERFACE_DESCRIPTOR_LENGTH,            // bLength
00534         INTERFACE_DESCRIPTOR,                   // bDescriptorType
00535         0x01,                                   // bInterfaceNumber
00536         0x00,                                   // bAlternateSetting
00537         0x00,                                   // bNumEndpoints
00538         AUDIO_CLASS,                            // bInterfaceClass
00539         SUBCLASS_AUDIOSTREAMING,                // bInterfaceSubClass
00540         0x00,                                   // bInterfaceProtocol
00541         0x00,                                   // iInterface
00542 
00543         // Interface 1, Alternate Setting 1, Audio Streaming - Operational
00544         INTERFACE_DESCRIPTOR_LENGTH,            // bLength
00545         INTERFACE_DESCRIPTOR,                   // bDescriptorType
00546         0x01,                                   // bInterfaceNumber
00547         0x01,                                   // bAlternateSetting
00548         0x01,                                   // bNumEndpoints
00549         AUDIO_CLASS,                            // bInterfaceClass
00550         SUBCLASS_AUDIOSTREAMING,                // bInterfaceSubClass
00551         0x00,                                   // bInterfaceProtocol
00552         0x00,                                   // iInterface
00553 
00554         // Audio Streaming Interface
00555         STREAMING_INTERFACE_DESCRIPTOR_LENGTH,  // bLength
00556         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00557         STREAMING_GENERAL,                      // bDescriptorSubtype
00558         0x01,                                   // bTerminalLink
00559         0x00,                                   // bDelay
00560         LSB( FORMAT_PCM ),                      // wFormatTag
00561         MSB( FORMAT_PCM ),                      // wFormatTag
00562 
00563         // Audio Type I Format
00564         FORMAT_TYPE_I_DESCRIPTOR_LENGTH,        // bLength
00565         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00566         STREAMING_FORMAT_TYPE,                  // bDescriptorSubtype
00567         FORMAT_TYPE_I,                          // bFormatType
00568         channel_nb_in,                          // bNrChannels
00569         0x02,                                   // bSubFrameSize
00570         16,                                     // bBitResolution
00571         0x01,                                   // bSamFreqType
00572         LSB( FREQ_IN ),                         // tSamFreq
00573         ( FREQ_IN >> 8 ) & 0xff,                // tSamFreq
00574         ( FREQ_IN >> 16 ) & 0xff,               // tSamFreq
00575 
00576         // Endpoint - Standard Descriptor
00577         ENDPOINT_DESCRIPTOR_LENGTH + 2,         // bLength
00578         ENDPOINT_DESCRIPTOR,                    // bDescriptorType
00579         PHY_TO_DESC( EPISO_OUT ),               // bEndpointAddress
00580         E_ISOCHRONOUS,                          // bmAttributes
00581         LSB( PACKET_SIZE_ISO_IN ),                 // wMaxPacketSize
00582         MSB( PACKET_SIZE_ISO_IN ),                 // wMaxPacketSize
00583         0x01,                                   // bInterval
00584         0x00,                                   // bRefresh
00585         0x00,                                   // bSynchAddress
00586 
00587         // Endpoint - Audio Streaming
00588         STREAMING_ENDPOINT_DESCRIPTOR_LENGTH,   // bLength
00589         ENDPOINT_DESCRIPTOR_TYPE,               // bDescriptorType
00590         ENDPOINT_GENERAL,                       // bDescriptor
00591         0x00,                                   // bmAttributes
00592         0x00,                                   // bLockDelayUnits
00593         LSB( 0x0000 ),                          // wLockDelay
00594         MSB( 0x0000 ),                          // wLockDelay
00595 
00596 
00597 
00598 
00599 
00600 
00601 
00602         // Interface 1, Alternate Setting 0, Audio Streaming - Zero Bandwith
00603         INTERFACE_DESCRIPTOR_LENGTH,            // bLength
00604         INTERFACE_DESCRIPTOR,                   // bDescriptorType
00605         0x02,                                   // bInterfaceNumber
00606         0x00,                                   // bAlternateSetting
00607         0x00,                                   // bNumEndpoints
00608         AUDIO_CLASS,                            // bInterfaceClass
00609         SUBCLASS_AUDIOSTREAMING,                // bInterfaceSubClass
00610         0x00,                                   // bInterfaceProtocol
00611         0x00,                                   // iInterface
00612 
00613         // Interface 1, Alternate Setting 1, Audio Streaming - Operational
00614         INTERFACE_DESCRIPTOR_LENGTH,            // bLength
00615         INTERFACE_DESCRIPTOR,                   // bDescriptorType
00616         0x02,                                   // bInterfaceNumber
00617         0x01,                                   // bAlternateSetting
00618         0x01,                                   // bNumEndpoints
00619         AUDIO_CLASS,                            // bInterfaceClass
00620         SUBCLASS_AUDIOSTREAMING,                // bInterfaceSubClass
00621         0x00,                                   // bInterfaceProtocol
00622         0x00,                                   // iInterface
00623 
00624         // Audio Streaming Interface
00625         STREAMING_INTERFACE_DESCRIPTOR_LENGTH,  // bLength
00626         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00627         SUBCLASS_AUDIOCONTROL,                  // bDescriptorSubtype
00628         0x05,                                   // bTerminalLink (output terminal microphone)
00629         0x01,                                   // bDelay
00630         0x01,                                   // wFormatTag
00631         0x00,                                   // wFormatTag
00632 
00633         // Audio Type I Format
00634         FORMAT_TYPE_I_DESCRIPTOR_LENGTH,        // bLength
00635         INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
00636         SUBCLASS_AUDIOSTREAMING,                // bDescriptorSubtype
00637         FORMAT_TYPE_I,                          // bFormatType
00638         channel_nb_out,                         // bNrChannels
00639         0x02,                                   // bSubFrameSize
00640         0x10,                                   // bBitResolution
00641         0x01,                                   // bSamFreqType
00642         LSB( FREQ_OUT ),                        // tSamFreq
00643         ( FREQ_OUT >> 8 ) & 0xff,               // tSamFreq
00644         ( FREQ_OUT >> 16 ) & 0xff,              // tSamFreq
00645 
00646         // Endpoint - Standard Descriptor
00647         ENDPOINT_DESCRIPTOR_LENGTH + 2,         // bLength
00648         ENDPOINT_DESCRIPTOR,                    // bDescriptorType
00649         PHY_TO_DESC( EPISO_IN ),                // bEndpointAddress
00650         E_ISOCHRONOUS,                          // bmAttributes
00651         LSB( PACKET_SIZE_ISO_OUT ),                 // wMaxPacketSize
00652         MSB( PACKET_SIZE_ISO_OUT ),                 // wMaxPacketSize
00653         0x01,                                   // bInterval
00654         0x00,                                   // bRefresh
00655         0x00,                                   // bSynchAddress
00656 
00657         // Endpoint - Audio Streaming
00658         STREAMING_ENDPOINT_DESCRIPTOR_LENGTH,   // bLength
00659         ENDPOINT_DESCRIPTOR_TYPE,               // bDescriptorType
00660         ENDPOINT_GENERAL,                       // bDescriptor
00661         0x00,                                   // bmAttributes
00662         0x00,                                   // bLockDelayUnits
00663         LSB( 0x0000 ),                          // wLockDelay
00664         MSB( 0x0000 ),                          // wLockDelay
00665 
00666         // Terminator
00667         0                                       // bLength
00668     };
00669     return configDescriptor;
00670 }
00671 
00672 uint8_t *USBAudio::stringIinterfaceDesc()
00673 {
00674     static uint8_t stringIinterfaceDescriptor[] =
00675     {
00676         0x0c,                           //bLength
00677         STRING_DESCRIPTOR,              //bDescriptorType 0x03
00678         'A', 0, 'u', 0, 'd', 0, 'i', 0, 'o', 0 //bString iInterface - Audio
00679     };
00680     return stringIinterfaceDescriptor;
00681 }
00682 
00683 uint8_t *USBAudio::stringIproductDesc()
00684 {
00685     static uint8_t stringIproductDescriptor[] =
00686     {
00687         0x16,                                                       //bLength
00688         STRING_DESCRIPTOR,                                          //bDescriptorType 0x03
00689         'M', 0, 'b', 0, 'e', 0, 'd', 0, ' ', 0, 'A', 0, 'u', 0, 'd', 0, 'i', 0, 'o', 0 //bString iProduct - Mbed Audio
00690     };
00691     return stringIproductDescriptor;
00692 }
00693