Demos/Device/ClassDriver/AudioOutput/AudioOutput.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  Main source file for the AudioOutput demo. This file contains the main tasks of
  34  *  the demo and is responsible for the initial application hardware configuration.
  35  */
  36
  37 #include "AudioOutput.h"
  38
  39 /** LUFA Audio Class driver interface configuration and state information. This structure is
  40  *  passed to all Audio Class driver functions, so that multiple instances of the same class
  41  *  within a device can be differentiated from one another.
  42  */
  43 USB_ClassInfo_Audio_Device_t Speaker_Audio_Interface =
  44         {
  45                 .Config =
  46                         {
  47                                 .StreamingInterfaceNumber = 1,
  48
  49                                 .DataINEndpointNumber     = AUDIO_STREAM_EPNUM,
  50                                 .DataINEndpointSize       = AUDIO_STREAM_EPSIZE,
  51                         },
  52
  53                 .State =
  54                         {
  55                                 // Leave all state values to their defaults
  56                         }
  57         };
  58
  59 /** Main program entry point. This routine contains the overall program flow, including initial
  60  *  setup of all components and the main program loop.
  61  */
  62 int main(void)
  63 {
  64         SetupHardware();
  65
  66         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  67
  68         for (;;)
  69         {
  70                 if (Speaker_Audio_Interface.State.InterfaceEnabled)
  71                   ProcessNextSample();
  72
  73                 Audio_Device_USBTask(&Speaker_Audio_Interface);
  74                 USB_USBTask();
  75         }
  76 }
  77
  78 /** Configures the board hardware and chip peripherals for the demo's functionality. */
  79 void SetupHardware(void)
  80 {
  81         /* Disable watchdog if enabled by bootloader/fuses */
  82         MCUSR &= ~(1 << WDRF);
  83         wdt_disable();
  84
  85         /* Disable clock division */
  86         clock_prescale_set(clock_div_1);
  87
  88         /* Hardware Initialization */
  89         LEDs_Init();
  90         USB_Init();
  91 }
  92
  93 /** Processes the next audio sample by reading the last ADC conversion and writing it to the audio
  94  *  interface, each time the sample reload timer period elapses to give a constant sample rate.
  95  */
  96 void ProcessNextSample(void)
  97 {
  98         if ((TIFR0 & (1 << OCF0A)) && Audio_Device_IsSampleReceived(&Speaker_Audio_Interface))
  99         {
 100                 /* Clear the sample reload timer */
 101                 TIFR0 |= (1 << OCF0A);
 102
 103                 /* Retrieve the signed 16-bit left and right audio samples */
 104                 int16_t LeftSample_16Bit  = (int16_t)Audio_Device_ReadSample16();
 105                 int16_t RightSample_16Bit = (int16_t)Audio_Device_ReadSample16();
 106
 107                 /* Massage signed 16-bit left and right audio samples into signed 8-bit */
 108                 int8_t  LeftSample_8Bit   = (LeftSample_16Bit  >> 8);
 109                 int8_t  RightSample_8Bit  = (RightSample_16Bit >> 8);
 110
 111                 /* Mix the two channels together to produce a mono, 8-bit sample */
 112                 int8_t  MixedSample_8Bit  = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
 113
 114 #if defined(AUDIO_OUT_MONO)
 115                 /* Load the sample into the PWM timer channel */
 116                 OCRxA = ((uint8_t)MixedSample_8Bit ^ (1 << 7));
 117 #elif defined(AUDIO_OUT_STEREO)
 118                 /* Load the dual 8-bit samples into the PWM timer channels */
 119                 OCRxA = ((uint8_t)LeftSample_8Bit  ^ (1 << 7));
 120                 OCRxB = ((uint8_t)RightSample_8Bit ^ (1 << 7));
 121 #elif defined(AUDIO_OUT_PORTC)
 122                 PORTC = MixedSample_8Bit;
 123 #else
 124                 uint8_t LEDMask = LEDS_NO_LEDS;
 125
 126                 /* Make mixed sample value positive (absolute) */
 127                 if (MixedSample_8Bit < 0)
 128                   MixedSample_8Bit = -MixedSample_8Bit;
 129
 130                 if (MixedSample_8Bit > ((128 / 8) * 1))
 131                   LEDMask |= LEDS_LED1;
 132
 133                 if (MixedSample_8Bit > ((128 / 8) * 2))
 134                   LEDMask |= LEDS_LED2;
 135
 136                 if (MixedSample_8Bit > ((128 / 8) * 3))
 137                   LEDMask |= LEDS_LED3;
 138
 139                 if (MixedSample_8Bit > ((128 / 8) * 4))
 140                   LEDMask |= LEDS_LED4;
 141
 142                 LEDs_SetAllLEDs(LEDMask);
 143 #endif
 144         }
 145 }
 146
 147 /** Event handler for the library USB Connection event. */
 148 void EVENT_USB_Connect(void)
 149 {
 150         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 151
 152         /* Sample reload timer initialization */
 153         OCR0A   = (F_CPU / AUDIO_SAMPLE_FREQUENCY) - 1;
 154         TCCR0A  = (1 << WGM01);  // CTC mode
 155         TCCR0B  = (1 << CS00);   // Fcpu speed
 156
 157 #if defined(AUDIO_OUT_MONO)
 158         /* Set speaker as output */
 159         DDRC   |= (1 << 6);
 160 #elif defined(AUDIO_OUT_STEREO)
 161         /* Set speakers as outputs */
 162         DDRC   |= ((1 << 6) | (1 << 5));
 163 #elif defined(AUDIO_OUT_PORTC)
 164         /* Set PORTC as outputs */
 165         DDRC   |= 0xFF;
 166 #endif
 167
 168 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 169         /* PWM speaker timer initialization */
 170         TCCRxA  = ((1 << WGMx0) | (1 << COMxA1) | (1 << COMxA0)
 171                 | (1 << COMxB1) | (1 << COMxB0)); // Set on match, clear on TOP
 172         TCCRxB  = ((1 << WGMx2) | (1 << CSx0));  // Fast 8-Bit PWM, Fcpu speed
 173 #endif
 174 }
 175
 176 /** Event handler for the library USB Disconnection event. */
 177 void EVENT_USB_Disconnect(void)
 178 {
 179         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 180
 181         /* Stop the sample reload timer */
 182         TCCR0B = 0;
 183
 184 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 185         /* Stop the PWM generation timer */
 186         TCCRxB = 0;
 187 #endif
 188
 189 #if defined(AUDIO_OUT_MONO)
 190         /* Set speaker as input to reduce current draw */
 191         DDRC   &= ~(1 << 6);
 192 #elif defined(AUDIO_OUT_STEREO)
 193         /* Set speakers as inputs to reduce current draw */
 194         DDRC   &= ~((1 << 6) | (1 << 5));
 195 #elif defined(AUDIO_OUT_PORTC)
 196         /* Set PORTC low */
 197         PORTC  = 0x00;
 198 #endif
 199 }
 200
 201 /** Event handler for the library USB Configuration Changed event. */
 202 void EVENT_USB_ConfigurationChanged(void)
 203 {
 204         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 205
 206         if (!(Audio_Device_ConfigureEndpoints(&Speaker_Audio_Interface)))
 207           LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 208 }
 209
 210 /** Event handler for the library USB Unhandled Control Packet event. */
 211 void EVENT_USB_UnhandledControlPacket(void)
 212 {
 213         Audio_Device_ProcessControlPacket(&Speaker_Audio_Interface);
 214 }