AudioInput.c 8.68 KB
Newer Older
1
2
/*
             LUFA Library
3
     Copyright (C) Dean Camera, 2011.
4

5
  dean [at] fourwalledcubicle [dot] com
6
           www.lufa-lib.org
7
8
9
*/

/*
10
  Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)
11

12
  Permission to use, copy, modify, distribute, and sell this
13
  software and its documentation for any purpose is hereby granted
14
  without fee, provided that the above copyright notice appear in
15
  all copies and that both that the copyright notice and this
16
17
18
  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
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
  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.
*/

/** \file
 *
 *  Main source file for the AudioInput demo. This file contains the main tasks of
 *  the demo and is responsible for the initial application hardware configuration.
 */

#include "AudioInput.h"

/** LUFA Audio Class driver interface configuration and state information. This structure is
 *  passed to all Audio Class driver functions, so that multiple instances of the same class
 *  within a device can be differentiated from one another.
 */
USB_ClassInfo_Audio_Device_t Microphone_Audio_Interface =
	{
		.Config =
			{
				.StreamingInterfaceNumber = 1,

				.DataINEndpointNumber     = AUDIO_STREAM_EPNUM,
				.DataINEndpointSize       = AUDIO_STREAM_EPSIZE,
			},
	};

54
/** Current audio sampling frequency of the streaming audio endpoint. */
55
static uint32_t CurrentAudioSampleFrequency = 48000;
56

57

58
59
60
61
62
63
64
65
66
/** Main program entry point. This routine contains the overall program flow, including initial
 *  setup of all components and the main program loop.
 */
int main(void)
{
	SetupHardware();

	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
	sei();
67

68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
	for (;;)
	{
		Audio_Device_USBTask(&Microphone_Audio_Interface);
		USB_USBTask();
	}
}

/** Configures the board hardware and chip peripherals for the demo's functionality. */
void SetupHardware(void)
{
	/* Disable watchdog if enabled by bootloader/fuses */
	MCUSR &= ~(1 << WDRF);
	wdt_disable();

	/* Disable clock division */
	clock_prescale_set(clock_div_1);
84

85
86
	/* Hardware Initialization */
	LEDs_Init();
87
	Buttons_Init();
88
89
	ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32);
	ADC_SetupChannel(MIC_IN_ADC_CHANNEL);
90
	USB_Init();
91

92
93
94
95
	/* Start the ADC conversion in free running mode */
	ADC_StartReading(ADC_REFERENCE_AVCC | ADC_RIGHT_ADJUSTED | MIC_IN_ADC_MUX_MASK);
}

96
97
/** ISR to handle the reloading of the data endpoint with the next sample. */
ISR(TIMER0_COMPA_vect, ISR_BLOCK)
98
{
99
100
	uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint();

101
	/* Check that the USB bus is ready for the next sample to write */
102
	if (Audio_Device_IsReadyForNextSample(&Microphone_Audio_Interface))
103
	{
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
		int16_t AudioSample;

		#if defined(USE_TEST_TONE)
			static uint8_t SquareWaveSampleCount;
			static int16_t CurrentWaveValue;
			
			/* In test tone mode, generate a square wave at 1/256 of the sample rate */
			if (SquareWaveSampleCount++ == 0xFF)
			  CurrentWaveValue ^= 0x8000;
			
			/* Only generate audio if the board button is being pressed */
			AudioSample = (Buttons_GetStatus() & BUTTONS_BUTTON1) ? CurrentWaveValue : 0;
		#else
			/* Audio sample is ADC value scaled to fit the entire range */
			AudioSample = ((SAMPLE_MAX_RANGE / ADC_MAX_RANGE) * ADC_GetResult());

			#if defined(MICROPHONE_BIASED_TO_HALF_RAIL)
			/* Microphone is biased to half rail voltage, subtract the bias from the sample value */
			AudioSample -= (SAMPLE_MAX_RANGE / 2);
			#endif
124
		#endif
125
		
126
127
		Audio_Device_WriteSample16(&Microphone_Audio_Interface, AudioSample);
	}
128
129

	Endpoint_SelectEndpoint(PrevEndpoint);
130
131
132
133
134
135
136
137
}

/** Event handler for the library USB Connection event. */
void EVENT_USB_Device_Connect(void)
{
	LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);

	/* Sample reload timer initialization */
138
	TIMSK0  = (1 << OCIE0A);
139
	OCR0A   = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
	TCCR0A  = (1 << WGM01);  // CTC mode
	TCCR0B  = (1 << CS01);   // Fcpu/8 speed
}

/** Event handler for the library USB Disconnection event. */
void EVENT_USB_Device_Disconnect(void)
{
	/* Stop the sample reload timer */
	TCCR0B = 0;

	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
}

/** Event handler for the library USB Configuration Changed event. */
void EVENT_USB_Device_ConfigurationChanged(void)
{
156
157
158
159
160
	bool ConfigSuccess = true;

	ConfigSuccess &= Audio_Device_ConfigureEndpoints(&Microphone_Audio_Interface);

	LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
161
162
}

163
164
/** Event handler for the library USB Control Request reception event. */
void EVENT_USB_Device_ControlRequest(void)
165
166
167
{
	Audio_Device_ProcessControlRequest(&Microphone_Audio_Interface);
}
168

169
170
171
172
173
174
175
176
177
178
179
180
/** Audio class driver callback for the setting and retrieval of streaming endpoint properties. This callback must be implemented
 *  in the user application to handle property manipulations on streaming audio endpoints.
 *
 *  When the DataLength parameter is NULL, this callback should only indicate whether the specified operation is valid for
 *  the given endpoint index, and should return as fast as possible. When non-NULL, this value may be altered for GET operations
 *  to indicate the size of the retreived data.
 *
 *  \note The length of the retrieved data stored into the Data buffer on GET operations should not exceed the initial value
 *        of the \c DataLength parameter.
 *
 *  \param[in,out] AudioInterfaceInfo  Pointer to a structure containing an Audio Class configuration and state.
 *  \param[in]     EndpointProperty    Property of the endpoint to get or set, a value from Audio_ClassRequests_t.
181
 *  \param[in]     EndpointAddress     Address of the streaming endpoint whose property is being referenced.
182
183
184
185
186
187
188
189
190
 *  \param[in]     EndpointControl     Parameter of the endpoint to get or set, a value from Audio_EndpointControls_t.
 *  \param[in,out] DataLength          For SET operations, the length of the parameter data to set. For GET operations, the maximum
 *                                     length of the retrieved data. When NULL, the function should return whether the given property
 *                                     and parameter is valid for the requested endpoint without reading or modifying the Data buffer.
 *  \param[in,out] Data                Pointer to a location where the parameter data is stored for SET operations, or where
 *                                     the retrieved data is to be stored for GET operations.
 *
 *  \return Boolean true if the property get/set was successful, false otherwise
 */
191
192
193
194
195
196
bool CALLBACK_Audio_Device_GetSetEndpointProperty(USB_ClassInfo_Audio_Device_t* const AudioInterfaceInfo,
                                                  const uint8_t EndpointProperty,
                                                  const uint8_t EndpointAddress,
                                                  const uint8_t EndpointControl,
                                                  uint16_t* const DataLength,
                                                  uint8_t* Data)
197
198
{
	/* Check the requested endpoint to see if a supported endpoint is being manipulated */
199
	if (EndpointAddress == (ENDPOINT_DESCRIPTOR_DIR_IN | Microphone_Audio_Interface.Config.DataINEndpointNumber))
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
	{
		/* Check the requested control to see if a supported control is being manipulated */
		if (EndpointControl == AUDIO_EPCONTROL_SamplingFreq)
		{
			/* Check the requested property to see if a supported property is being manipulated */
			if (EndpointProperty == AUDIO_REQ_SetCurrent)
			{
				/* Check if we are just testing for a valid property, or actually adjusting it */
				if (DataLength != NULL)
				{
					/* Set the new sampling frequency to the value given by the host */
					CurrentAudioSampleFrequency = (((uint32_t)Data[2] << 16) | ((uint32_t)Data[1] << 8) | (uint32_t)Data[0]);

					/* Adjust sample reload timer to the new frequency */
					OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);				
				}
				
				return true;
			}
			else if (EndpointProperty == AUDIO_REQ_GetCurrent)
			{
				/* Check if we are just testing for a valid property, or actually reading it */
				if (DataLength != NULL)
				{
					*DataLength = 3;

					Data[2] = (CurrentAudioSampleFrequency >> 16);
					Data[1] = (CurrentAudioSampleFrequency >> 8);
					Data[0] = (CurrentAudioSampleFrequency &  0xFF);					
				}
				
				return true;
			}
		}
	}
	
	return false;
}