Audio.h 26.1 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
/*
             LUFA Library
     Copyright (C) Dean Camera, 2009.
              
  dean [at] fourwalledcubicle [dot] com
      www.fourwalledcubicle.com
*/

/*
  Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)

  Permission to use, copy, modify, and distribute this software
  and its documentation for any purpose and without fee is hereby
  granted, provided that the above copyright notice appear in all
  copies and that both that the copyright notice and this
  permission notice and warranty disclaimer appear in supporting
  documentation, and that the name of the author not be used in
  advertising or publicity pertaining to distribution of the
  software without specific, written prior permission.

  The author disclaim all warranties with regard to this
  software, including all implied warranties of merchantability
  and fitness.  In no event shall the author be liable for any
  special, indirect or consequential damages or any damages
  whatsoever resulting from loss of use, data or profits, whether
  in an action of contract, negligence or other tortious action,
  arising out of or in connection with the use or performance of
  this software.
*/

31
32
33
34
35
36
37
38
39
40
41
42
43
44
/** \ingroup Group_USBDeviceClassDrivers
 *  @defgroup Group_USBClassAudioDevice Audio Device Class Driver - LUFA/Drivers/Class/Device/Audio.h
 *
 *  \section Sec_Dependencies Module Source Dependencies
 *  The following files must be built with any user project that uses this module:
 *    - LUFA/Drivers/USB/Class/Device/Audio.c
 *
 *  \section Module Description
 *  Functions, macros, variables, enums and types related to the management of USB Audio Class interfaces
 *  within a USB device.
 *
 *  @{
 */

45
46
47
48
49
50
51
52
#ifndef _AUDIO_CLASS_H_
#define _AUDIO_CLASS_H_

	/* Includes: */
		#include "../../USB.h"

		#include <string.h>

53
54
55
56
57
	/* Enable C linkage for C++ Compilers: */
		#if defined(__cplusplus)
			extern "C" {
		#endif

58
	/* Macros: */
59
60
		/** Descriptor header constant to indicate a Audio class interface descriptor. */
		#define DTYPE_AudioInterface         0x24
61

62
63
		/** Descriptor header constant to indicate a Audio class endpoint descriptor. */
		#define DTYPE_AudioEndpoint          0x25
64

65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
		/** Audio class descriptor subtype value for a Audio class specific header descriptor. */
		#define DSUBTYPE_Header              0x01

		/** Audio class descriptor subtype value for an Output Terminal Audio class specific descriptor. */
		#define DSUBTYPE_InputTerminal       0x02

		/** Audio class descriptor subtype value for an Input Terminal Audio class specific descriptor. */
		#define DSUBTYPE_OutputTerminal      0x03

		/** Audio class descriptor subtype value for a Feature Unit Audio class specific descriptor. */
		#define DSUBTYPE_FeatureUnit         0x06

		/** Audio class descriptor subtype value for a general Audio class specific descriptor. */
		#define DSUBTYPE_General             0x01

		/** Audio class descriptor subtype value for an Audio class specific descriptor indicating the format of an audio stream. */
		#define DSUBTYPE_Format              0x02
		
		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
		#define CHANNEL_LEFT_FRONT           (1 << 0)
85
86

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
87
		#define CHANNEL_RIGHT_FRONT          (1 << 1)
88
89

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
90
		#define CHANNEL_CENTER_FRONT         (1 << 2)
91
92

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
93
		#define CHANNEL_LOW_FREQ_ENHANCE     (1 << 3)
94
95

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
96
		#define CHANNEL_LEFT_SURROUND        (1 << 4)
97
98

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
99
		#define CHANNEL_RIGHT_SURROUND       (1 << 5)
100
101

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
102
		#define CHANNEL_LEFT_OF_CENTER       (1 << 6)
103
104

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
105
		#define CHANNEL_RIGHT_OF_CENTER      (1 << 7)
106
107

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
108
		#define CHANNEL_SURROUND             (1 << 8)
109
110

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
111
		#define CHANNEL_SIDE_LEFT            (1 << 9)
112
113

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
114
		#define CHANNEL_SIDE_RIGHT           (1 << 10)
115
116

		/** Supported channel mask for an Audio class terminal descriptor. See the Audio class specification for more details. */
117
118
119
120
		#define CHANNEL_TOP                  (1 << 11)

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
		#define FEATURE_MUTE                 (1 << 0)
121
122

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
123
		#define FEATURE_VOLUME               (1 << 1)
124
125

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
126
		#define FEATURE_BASS                 (1 << 2)
127
128

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
129
		#define FEATURE_MID                  (1 << 3)
130
131

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
132
		#define FEATURE_TREBLE               (1 << 4)
133
134

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
135
		#define FEATURE_GRAPHIC_EQUALIZER    (1 << 5)
136
137
138
139

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
140
		#define FEATURE_AUTOMATIC_GAIN       (1 << 6)
141
142

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
143
		#define FEATURE_DELAY                (1 << 7)
144
145

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
146
		#define FEATURE_BASS_BOOST           (1 << 8)
147
148

		/** Supported feature mask for an Audio class feature unit descriptor. See the Audio class specification for more details. */
149
150
		#define FEATURE_BASS_LOUDNESS        (1 << 9)

151
		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
152
		#define TERMINAL_UNDEFINED           0x0100
153
154

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
155
		#define TERMINAL_STREAMING           0x0101
156
157

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
158
		#define TERMINAL_VENDOR              0x01FF
159
160

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
161
		#define TERMINAL_IN_UNDEFINED        0x0200
162
163

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
164
		#define TERMINAL_IN_MIC              0x0201
165
166

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
167
		#define TERMINAL_IN_DESKTOP_MIC      0x0202
168
169

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
170
		#define TERMINAL_IN_PERSONAL_MIC     0x0203
171
172

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
173
		#define TERMINAL_IN_OMNIDIR_MIC      0x0204
174
175

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
176
		#define TERMINAL_IN_MIC_ARRAY        0x0205
177
178

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
179
		#define TERMINAL_IN_PROCESSING_MIC   0x0206
180
181

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
182
		#define TERMINAL_IN_OUT_UNDEFINED    0x0300
183
184

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
185
		#define TERMINAL_OUT_SPEAKER         0x0301
186
187

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
188
		#define TERMINAL_OUT_HEADPHONES      0x0302
189
190

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
191
		#define TERMINAL_OUT_HEAD_MOUNTED    0x0303
192
193

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
194
		#define TERMINAL_OUT_DESKTOP         0x0304
195
196

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
197
		#define TERMINAL_OUT_ROOM            0x0305
198
199

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
200
		#define TERMINAL_OUT_COMMUNICATION   0x0306
201
202

		/** Terminal type constant for an Audio class terminal descriptor. See the Audio class specification for more details. */		
203
204
205
206
207
208
		#define TERMINAL_OUT_LOWFREQ         0x0307

		/** Convenience macro, to fill a 24-bit AudioSampleFreq_t structure with the given sample rate as a 24-bit number.
		 *
		 *  \param freq  Required audio sampling frequency in HZ
		 */
209
		#define AUDIO_SAMPLE_FREQ(freq)  {LowWord: ((uint32_t)freq & 0x00FFFF), HighByte: (((uint32_t)freq >> 16) & 0x0000FF)}
210
211
212
213
214
215
216
217
218
219
220
		
		/** 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 EP_ACCEPTS_ONLY_FULL_PACKETS (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 EP_ACCEPTS_SMALL_PACKETS     (0 << 7)
		
221
	/* Type Defines: */
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
		/** Type define for an Audio class specific interface descriptor. This follows a regular interface descriptor to
		 *  supply extra information about the audio device's layout to the host. See the USB Audio specification for more
		 *  details.
		 */
		typedef struct
		{
			USB_Descriptor_Header_t   Header; /**< Regular descriptor header containing the descriptor's type and length */
			uint8_t                   Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */

			uint16_t                  ACSpecification; /**< Binary coded decimal value, indicating the supported Audio Class specification version */
			uint16_t                  TotalLength; /**< Total length of the Audio class specific descriptors, including this descriptor */
			
			uint8_t                   InCollection; /**< Total number of audio class interfaces within this device */
			uint8_t                   InterfaceNumbers[1]; /**< Interface numbers of each audio interface */
		} USB_AudioInterface_AC_t;
		
		/** Type define for an Audio class specific Feature Unit descriptor. This indicates to the host what features
		 *  are present in the device's audio stream for basic control, such as per-channel volume. See the USB Audio
		 *  specification for more details.
		 */
		typedef struct
		{
			USB_Descriptor_Header_t   Header; /**< Regular descriptor header containing the descriptor's type and length */
			uint8_t                   Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
			
			uint8_t                   UnitID; /**< ID value of this feature unit - must be a unique value within the device */
			uint8_t                   SourceID; /**< Source ID value of the audio source input into this feature unit */
			
			uint8_t                   ControlSize; /**< Size of each element in the ChanelControlls array */
			uint8_t                   ChannelControls[3]; /**< Feature masks for the control channel, and each separate audio channel */
			
			uint8_t                   FeatureUnitStrIndex; /**< Index of a string descriptor describing this descriptor within the device */
		} USB_AudioFeatureUnit_t;

		/** Type define for an Audio class specific input terminal descriptor. This indicates to the host that the device
		 *  contains an input audio source, either from a physical terminal on the device, or a logical terminal (for example,
		 *  a USB endpoint). See the USB Audio specification for more details.
		 */
		typedef struct
		{
			USB_Descriptor_Header_t   Header; /**< Regular descriptor header containing the descriptor's type and length */
			uint8_t                   Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
		
			uint8_t                   TerminalID; /**< ID value of this terminal unit - must be a unique value within the device */
			uint16_t                  TerminalType; /**< Type of terminal, a TERMINAL_* mask */
			uint8_t                   AssociatedOutputTerminal; /**< ID of associated output terminal, for physically grouped terminals
			                                                     *   such as the speaker and microphone of a phone handset
			                                                     */
			uint8_t                   TotalChannels; /**< Total number of separate audio channels within this interface (right, left, etc.) */
			uint16_t                  ChannelConfig; /**< CHANNEL_* masks indicating what channel layout is supported by this terminal */
			
			uint8_t                   ChannelStrIndex; /**< Index of a string descriptor describing this channel within the device */
			uint8_t                   TerminalStrIndex; /**< Index of a string descriptor describing this descriptor within the device */
		} USB_AudioInputTerminal_t;

		/** Type define for an Audio class specific output terminal descriptor. This indicates to the host that the device
		 *  contains an output audio sink, either to a physical terminal on the device, or a logical terminal (for example,
		 *  a USB endpoint). See the USB Audio specification for more details.
		 */
		typedef struct
		{
			USB_Descriptor_Header_t   Header; /**< Regular descriptor header containing the descriptor's type and length */
			uint8_t                   Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
		
			uint8_t                   TerminalID; /**< ID value of this terminal unit - must be a unique value within the device */
			uint16_t                  TerminalType; /**< Type of terminal, a TERMINAL_* mask */
			uint8_t                   AssociatedInputTerminal; /**< ID of associated input terminal, for physically grouped terminals
			                                                    *   such as the speaker and microphone of a phone handset
			                                                    */
			uint8_t                   SourceID; /**< ID value of the unit this terminal's audio is sourced from */
			
			uint8_t                   TerminalStrIndex; /**< Index of a string descriptor describing this descriptor within the device */
		} USB_AudioOutputTerminal_t;
		
		/** Type define for an Audio class specific streaming interface descriptor. This indicates to the host
		 *  how audio streams within the device are formatted. See the USB Audio specification for more details.
		 */
		typedef struct
		{
			USB_Descriptor_Header_t   Header; /**< Regular descriptor header containing the descriptor's type and length */
			uint8_t                   Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
			
			uint8_t                   TerminalLink; /**< ID value of the output terminal this descriptor is describing */
			
			uint8_t                   FrameDelay; /**< Delay in frames resulting from the complete sample processing from input to output */
			uint16_t                  AudioFormat; /**< Format of the audio stream, see Audio Device Formats specification */
		} USB_AudioInterface_AS_t;
		
		/** Type define for a 24bit audio sample frequency structure. GCC does not contain a built in 24bit datatype,
		 *  this this structure is used to build up the value instead. Fill this structure with the SAMPLE_FREQ() macro.
		 */
		typedef struct
		{
			uint16_t                  LowWord; /**< Low 16 bits of the 24-bit value */
			uint8_t                   HighByte; /**< Upper 8 bits of the 24-bit value */
		} AudioSampleFreq_t;

		/** Type define for an Audio class specific audio format descriptor. This is used to give the host full details
		 *  about the number of channels, the sample resolution, acceptable sample frequencies and encoding method used
		 *  in the device's audio streams. See the USB Audio specification for more details.
		 */
		typedef struct
		{
			USB_Descriptor_Header_t   Header; /**< Regular descriptor header containing the descriptor's type and length */
			uint8_t                   Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */

			uint8_t                   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                   SampleFrequencyType; /**< Total number of sample frequencies supported by the device */			
			AudioSampleFreq_t         SampleFrequencies[1]; /**< Sample frequencies supported by the device */
		} USB_AudioFormat_t;
		
		/** 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.
		 */
		typedef struct
		{
			USB_Descriptor_Endpoint_t Endpoint; /**< Standard endpoint descriptor describing the audio endpoint */

			uint8_t                   Refresh; /**< Always set to zero */
			uint8_t                   SyncEndpointNumber; /**< Endpoint address to send synchronisation information to, if needed (zero otherwise) */
		} USB_AudioStreamEndpoint_Std_t;
					
		/** 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.
		 */
		typedef struct
		{
			USB_Descriptor_Header_t   Header; /**< Regular descriptor header containing the descriptor's type and length */
			uint8_t                   Subtype; /**< Sub type value used to distinguish between audio class specific descriptors */
			
			uint8_t                   Attributes; /**< Audio class specific endpoint attributes, such as ACCEPTS_SMALL_PACKETS */

			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 */
		} USB_AudioStreamEndpoint_Spc_t;	

364
365
366
367
		/** Type define for an Audio Class interface configuration and state structure. This structure should be used for each Audio
		 *  Class unit within the device, and passed (per-interface) to the Audio Class driver functions so that each Audio interface
		 *  has seperate state and configuration data and can be controlled seperately.
		 */
368
369
		typedef struct
		{
370
			uint8_t  StreamingInterfaceNumber; /**< Index of the Audio Streaming interface within the device this structure controls */
371

372
373
			uint8_t  DataINEndpointNumber; /**< Endpoint number of the incomming Audio Streaming data, if available (zero if unused) */
			uint16_t DataINEndpointSize; /**< Size in bytes of the incomming Audio Streaming data endpoint, if available (zero if unused) */
374

375
376
			uint8_t  DataOUTEndpointNumber; /**< Endpoint number of the outgoing Audio Streaming data, if available (zero if unused) */
			uint16_t DataOUTEndpointSize; /**< Size in bytes of the outgoing Audio Streaming data endpoint, if available (zero if unused) */
377

378
379
380
			bool     InterfaceEnabled; /**< Set and cleared by the class driver to indicate if the host has enabled the streaming endpoints
			                            *   of the Audio Streaming interface
			                            */
381
382
383
		} USB_ClassInfo_Audio_t;
		
	/* Function Prototypes: */
384
385
386
387
388
389
390
391
		/** Configures the endpoints of a given Audio interface, ready for use. This should be linked to the library
		 *  \ref EVENT_USB_ConfigurationChanged() event so that the endpoints are configured when the configuration containing the
		 *  given Audio interface is selected.
		 *
		 *  \param AudioInterfaceInfo  Pointer to a structure containing an Audio Class configuration and state.
		 *
		 *  \return Boolean true if the endpoints were sucessfully configured, false otherwise
		 */
392
		bool USB_Audio_ConfigureEndpoints(USB_ClassInfo_Audio_t* AudioInterfaceInfo);
393
394
395
396
397
398

		/** Processes incomming control requests from the host, that are directed to the given Audio class interface. This should be
		 *  linked to the library \ref EVENT_USB_UnhandledControlPacket() event.
		 *
		 *  \param AudioInterfaceInfo  Pointer to a structure containing an Audio Class configuration and state.
		 */
399
		void USB_Audio_ProcessControlPacket(USB_ClassInfo_Audio_t* AudioInterfaceInfo);
400
401
402
403
404
405

		/** General management task for a given Audio class interface, required for the correct operation of the interface. This should
		 *  be called frequently in the main program loop, before the master USB management task \ref USB_USBTask().
		 *
		 *  \param AudioInterfaceInfo  Pointer to a structure containing an Audio Class configuration and state.
		 */
406
		void USB_Audio_USBTask(USB_ClassInfo_Audio_t* AudioInterfaceInfo);
407
		
408
409
410
411
412
413
414
		/** Reads the next 8-bit audio sample from the current audio interface.
		 *
		 *  \note This should be preceeded immediately by a call to the USB_Audio_IsSampleReceived() function to ensure that
		 *        the correct endpoint is selected and ready for data.
		 *
		 *  \return  Signed 8-bit audio sample from the audio interface
		 */
415
		int8_t USB_Audio_ReadSample8(void);
416
417
418
419
420
421
422
423

		/** Reads the next 16-bit audio sample from the current audio interface.
		 *
		 *  \note This should be preceeded immediately by a call to the USB_Audio_IsSampleReceived() function to ensure that
		 *        the correct endpoint is selected and ready for data.
		 *
		 *  \return  Signed 16-bit audio sample from the audio interface
		 */
424
		int16_t USB_Audio_ReadSample16(void);
425
426
427
428
429
430
431
432

		/** Reads the next 24-bit audio sample from the current audio interface.
		 *
		 *  \note This should be preceeded immediately by a call to the USB_Audio_IsSampleReceived() function to ensure that
		 *        the correct endpoint is selected and ready for data.
		 *
		 *  \return  Signed 24-bit audio sample from the audio interface
		 */
433
		int32_t USB_Audio_ReadSample24(void);
434
435
436
437
438
439
440
441

		/** Writes the next 8-bit audio sample to the current audio interface.
		 *
		 *  \note This should be preceeded immediately by a call to the USB_Audio_IsReadyForNextSample() function to ensure that
		 *        the correct endpoint is selected and ready for data.
		 *
		 *  \param Sample  Signed 8-bit audio sample
		 */
442
		void USB_Audio_WriteSample8(int8_t Sample);
443
444
445
446
447
448
449
450

		/** Writes the next 16-bit audio sample to the current audio interface.
		 *
		 *  \note This should be preceeded immediately by a call to the USB_Audio_IsReadyForNextSample() function to ensure that
		 *        the correct endpoint is selected and ready for data.
		 *
		 *  \param Sample  Signed 16-bit audio sample
		 */
451
		void USB_Audio_WriteSample16(int16_t Sample);
452
453
454
455
456
457
458
459

		/** Writes the next 24-bit audio sample to the current audio interface.
		 *
		 *  \note This should be preceeded immediately by a call to the USB_Audio_IsReadyForNextSample() function to ensure that
		 *        the correct endpoint is selected and ready for data.
		 *
		 *  \param Sample  Signed 24-bit audio sample
		 */
460
		void USB_Audio_WriteSample24(int32_t Sample);
461
462
463
464
465
466
467

		/** Determines if the given audio interface is ready for a sample to be read from it.
		 *
		 *  \param AudioInterfaceInfo  Pointer to a structure containing an Audio Class configuration and state.
		 *
		 *  \return Boolean true if the given Audio interface has a sample to be read, false otherwise
		 */
468
		bool USB_Audio_IsSampleReceived(USB_ClassInfo_Audio_t* AudioInterfaceInfo);
469
470
471
472
473
474
475

		/** Determines if the given audio interface is ready to accept the next sample to be written to it.
		 *
		 *  \param AudioInterfaceInfo  Pointer to a structure containing an Audio Class configuration and state.
		 *
		 *  \return Boolean true if the given Audio interface is ready to accept the next sample, false otherwise
		 */
476
		bool USB_Audio_IsReadyForNextSample(USB_ClassInfo_Audio_t* AudioInterfaceInfo);
477
478
479
480
481
482

	/* Disable C linkage for C++ Compilers: */
		#if defined(__cplusplus)
			}
		#endif
		
483
#endif
484
485

/** @} */