AudioOutput.c 6.35 KB
Newer Older
1
2
/*
             LUFA Library
Dean Camera's avatar
Dean Camera committed
3
     Copyright (C) Dean Camera, 2010.
4
5
6
7
8
9
              
  dean [at] fourwalledcubicle [dot] com
      www.fourwalledcubicle.com
*/

/*
Dean Camera's avatar
Dean Camera committed
10
  Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
11

12
13
14
15
16
17
18
  Permission to use, copy, modify, distribute, and sell this 
  software and its documentation for any purpose is hereby granted
  without fee, 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 
19
20
21
22
23
24
25
26
27
28
29
30
  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
/** \file
 *
 *  Main source file for the AudioOutput demo. This file contains the main tasks of
 *  the demo and is responsible for the initial application hardware configuration.
 */

37
38
#include "AudioOutput.h"

39
40
41
42
/** 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.
 */
43
USB_ClassInfo_Audio_Device_t Speaker_Audio_Interface =
44
	{
45
46
47
		.Config =
			{
				.StreamingInterfaceNumber = 1,
48

49
50
				.DataOUTEndpointNumber    = AUDIO_STREAM_EPNUM,
				.DataOUTEndpointSize      = AUDIO_STREAM_EPSIZE,
51
			},
52
	};
53

54
55
56
/** Main program entry point. This routine contains the overall program flow, including initial
 *  setup of all components and the main program loop.
 */
57
int main(void)
58
59
60
61
{
	SetupHardware();

	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
62
	sei();
63
64
65
	
	for (;;)
	{
66
		ProcessNextSample();
67

68
		Audio_Device_USBTask(&Speaker_Audio_Interface);
69
70
71
72
		USB_USBTask();
	}
}

73
/** Configures the board hardware and chip peripherals for the demo's functionality. */
74
void SetupHardware(void)
75
76
77
78
79
{
	/* Disable watchdog if enabled by bootloader/fuses */
	MCUSR &= ~(1 << WDRF);
	wdt_disable();

80
81
	/* Disable clock division */
	clock_prescale_set(clock_div_1);
82
83
84
85
86
87

	/* Hardware Initialization */
	LEDs_Init();
	USB_Init();
}

88
89
90
/** Processes the next audio sample by reading the last ADC conversion and writing it to the audio
 *  interface, each time the sample reload timer period elapses to give a constant sample rate.
 */
91
void ProcessNextSample(void)
92
{
93
	/* Check if the sample reload timer period has elapsed, and that the USB bus is ready for a new sample */
94
	if ((TIFR0 & (1 << OCF0A)) && Audio_Device_IsSampleReceived(&Speaker_Audio_Interface))
95
96
97
98
	{
		/* Clear the sample reload timer */
		TIFR0 |= (1 << OCF0A);

99
100
101
		/* Retrieve the signed 16-bit left and right audio samples, convert to 8-bit */
		int8_t  LeftSample_8Bit   = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
		int8_t  RightSample_8Bit  = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
102

103
104
		/* Mix the two channels together to produce a mono, 8-bit sample */
		int8_t  MixedSample_8Bit  = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
105

106
#if defined(AUDIO_OUT_MONO)
107
		/* Load the sample into the PWM timer channel */
108
		OCR3A = (MixedSample_8Bit ^ (1 << 7));
109
110
#elif defined(AUDIO_OUT_STEREO)
		/* Load the dual 8-bit samples into the PWM timer channels */
111
112
		OCR3A = (LeftSample_8Bit  ^ (1 << 7));
		OCR3B = (RightSample_8Bit ^ (1 << 7));
113
#elif defined(AUDIO_OUT_PORTC)
114
		/* Load the 8-bit mixed sample into PORTC */
115
		PORTC = MixedSample_8Bit;
116
#endif
117

118
		uint8_t LEDMask = LEDS_NO_LEDS;
119

120
		/* Turn on LEDs as the sample amplitude increases */
121
		if (MixedSample_8Bit > 16)
122
		  LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3 | LEDS_LED4);
123
		else if (MixedSample_8Bit > 8)
124
		  LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3);
125
		else if (MixedSample_8Bit > 4)
126
		  LEDMask = (LEDS_LED1 | LEDS_LED2);
127
		else if (MixedSample_8Bit > 2)
128
		  LEDMask = (LEDS_LED1);
129

130
131
132
		LEDs_SetAllLEDs(LEDMask);
	}
}
133

134
/** Event handler for the library USB Connection event. */
135
void EVENT_USB_Device_Connect(void)
136
137
138
139
{
	LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
	
	/* Sample reload timer initialization */
140
	OCR0A   = (F_CPU / 8 / AUDIO_SAMPLE_FREQUENCY) - 1;
141
	TCCR0A  = (1 << WGM01);  // CTC mode
142
	TCCR0B  = (1 << CS01);   // Fcpu/8 speed
143
144
145
146
147
148
149
150
151
152
153
154
155
156

#if defined(AUDIO_OUT_MONO)
	/* Set speaker as output */
	DDRC   |= (1 << 6);
#elif defined(AUDIO_OUT_STEREO)
	/* Set speakers as outputs */
	DDRC   |= ((1 << 6) | (1 << 5));
#elif defined(AUDIO_OUT_PORTC)
	/* Set PORTC as outputs */
	DDRC   |= 0xFF;
#endif

#if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
	/* PWM speaker timer initialization */
157
158
159
	TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
	        | (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
	TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, Fcpu speed
160
#endif
161
162
}

163
/** Event handler for the library USB Disconnection event. */
164
void EVENT_USB_Device_Disconnect(void)
165
166
167
{
	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);

168
	/* Stop the sample reload timer */
169
	TCCR0B = 0;
170

171
#if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
172
	/* Stop the PWM generation timer */
173
	TCCR3B = 0;
174
#endif
175
176
177
178
179
180
181
182
183
184
185
186
187

#if defined(AUDIO_OUT_MONO)
	/* Set speaker as input to reduce current draw */
	DDRC   &= ~(1 << 6);
#elif defined(AUDIO_OUT_STEREO)
	/* Set speakers as inputs to reduce current draw */
	DDRC   &= ~((1 << 6) | (1 << 5));
#elif defined(AUDIO_OUT_PORTC)
	/* Set PORTC low */
	PORTC  = 0x00;
#endif
}

188
/** Event handler for the library USB Configuration Changed event. */
189
void EVENT_USB_Device_ConfigurationChanged(void)
190
191
192
{
	LEDs_SetAllLEDs(LEDMASK_USB_READY);
	
193
	if (!(Audio_Device_ConfigureEndpoints(&Speaker_Audio_Interface)))
194
195
196
	  LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
}

197
198
/** Event handler for the library USB Unhandled Control Request event. */
void EVENT_USB_Device_UnhandledControlRequest(void)
199
{
200
	Audio_Device_ProcessControlRequest(&Speaker_Audio_Interface);
201
}