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                                 .DataOUTEndpointNumber    = AUDIO_STREAM_EPNUM,
  50                                 .DataOUTEndpointSize      = AUDIO_STREAM_EPSIZE,
  51                         },
  52         };
  53
  54 /** Main program entry point. This routine contains the overall program flow, including initial
  55  *  setup of all components and the main program loop.
  56  */
  57 int main(void)
  58 {
  59         SetupHardware();
  60
  61         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  62
  63         for (;;)
  64         {
  65                 ProcessNextSample();
  66
  67                 Audio_Device_USBTask(&Speaker_Audio_Interface);
  68                 USB_USBTask();
  69         }
  70 }
  71
  72 /** Configures the board hardware and chip peripherals for the demo's functionality. */
  73 void SetupHardware(void)
  74 {
  75         /* Disable watchdog if enabled by bootloader/fuses */
  76         MCUSR &= ~(1 << WDRF);
  77         wdt_disable();
  78
  79         /* Disable clock division */
  80         clock_prescale_set(clock_div_1);
  81
  82         /* Hardware Initialization */
  83         LEDs_Init();
  84         USB_Init();
  85 }
  86
  87 /** Processes the next audio sample by reading the last ADC conversion and writing it to the audio
  88  *  interface, each time the sample reload timer period elapses to give a constant sample rate.
  89  */
  90 void ProcessNextSample(void)
  91 {
  92         /* Check if the sample reload timer period has elapsed, and that the USB bus is ready for a new sample */
  93         if ((TIFR0 & (1 << OCF0A)) && Audio_Device_IsSampleReceived(&Speaker_Audio_Interface))
  94         {
  95                 /* Clear the sample reload timer */
  96                 TIFR0 |= (1 << OCF0A);
  97
  98                 /* Retrieve the signed 16-bit left and right audio samples */
  99                 int16_t LeftSample_16Bit  = Audio_Device_ReadSample16(&Speaker_Audio_Interface);
 100                 int16_t RightSample_16Bit = Audio_Device_ReadSample16(&Speaker_Audio_Interface);
 101
 102                 /* Massage signed 16-bit left and right audio samples into signed 8-bit */
 103                 int8_t  LeftSample_8Bit   = (LeftSample_16Bit  >> 8);
 104                 int8_t  RightSample_8Bit  = (RightSample_16Bit >> 8);
 105
 106 #if !defined(AUDIO_OUT_STEREO)
 107                 /* Mix the two channels together to produce a mono, 8-bit sample */
 108                 int8_t  MixedSample_8Bit  = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
 109 #endif
 110
 111 #if defined(AUDIO_OUT_MONO)
 112                 /* Load the sample into the PWM timer channel */
 113                 OCR3A = ((uint8_t)MixedSample_8Bit ^ (1 << 7));
 114 #elif defined(AUDIO_OUT_STEREO)
 115                 /* Load the dual 8-bit samples into the PWM timer channels */
 116                 OCR3A = ((uint8_t)LeftSample_8Bit  ^ (1 << 7));
 117                 OCR3B = ((uint8_t)RightSample_8Bit ^ (1 << 7));
 118 #elif defined(AUDIO_OUT_PORTC)
 119                 /* Load the 8-bit mixed sample into PORTC */
 120                 PORTC = MixedSample_8Bit;
 121 #else
 122                 uint8_t LEDMask = LEDS_NO_LEDS;
 123
 124                 /* Make mixed sample value positive (absolute) */
 125                 MixedSample_8Bit = abs(MixedSample_8Bit);
 126
 127                 if (MixedSample_8Bit > 2)
 128                   LEDMask |= LEDS_LED1;
 129
 130                 if (MixedSample_8Bit > 4)
 131                   LEDMask |= LEDS_LED2;
 132
 133                 if (MixedSample_8Bit > 8)
 134                   LEDMask |= LEDS_LED3;
 135
 136                 if (MixedSample_8Bit > 16)
 137                   LEDMask |= LEDS_LED4;
 138
 139                 LEDs_SetAllLEDs(LEDMask);
 140 #endif
 141         }
 142 }
 143
 144 /** Event handler for the library USB Connection event. */
 145 void EVENT_USB_Connect(void)
 146 {
 147         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 148
 149         /* Sample reload timer initialization */
 150         OCR0A   = (F_CPU / AUDIO_SAMPLE_FREQUENCY) - 1;
 151         TCCR0A  = (1 << WGM01);  // CTC mode
 152         TCCR0B  = (1 << CS00);   // Fcpu speed
 153
 154 #if defined(AUDIO_OUT_MONO)
 155         /* Set speaker as output */
 156         DDRC   |= (1 << 6);
 157 #elif defined(AUDIO_OUT_STEREO)
 158         /* Set speakers as outputs */
 159         DDRC   |= ((1 << 6) | (1 << 5));
 160 #elif defined(AUDIO_OUT_PORTC)
 161         /* Set PORTC as outputs */
 162         DDRC   |= 0xFF;
 163 #endif
 164
 165 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 166         /* PWM speaker timer initialization */
 167         TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
 168                 | (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
 169         TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, Fcpu speed
 170 #endif
 171 }
 172
 173 /** Event handler for the library USB Disconnection event. */
 174 void EVENT_USB_Disconnect(void)
 175 {
 176         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 177
 178         /* Stop the sample reload timer */
 179         TCCR0B = 0;
 180
 181 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 182         /* Stop the PWM generation timer */
 183         TCCR3B = 0;
 184 #endif
 185
 186 #if defined(AUDIO_OUT_MONO)
 187         /* Set speaker as input to reduce current draw */
 188         DDRC   &= ~(1 << 6);
 189 #elif defined(AUDIO_OUT_STEREO)
 190         /* Set speakers as inputs to reduce current draw */
 191         DDRC   &= ~((1 << 6) | (1 << 5));
 192 #elif defined(AUDIO_OUT_PORTC)
 193         /* Set PORTC low */
 194         PORTC  = 0x00;
 195 #endif
 196 }
 197
 198 /** Event handler for the library USB Configuration Changed event. */
 199 void EVENT_USB_ConfigurationChanged(void)
 200 {
 201         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 202
 203         if (!(Audio_Device_ConfigureEndpoints(&Speaker_Audio_Interface)))
 204           LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 205 }
 206
 207 /** Event handler for the library USB Unhandled Control Packet event. */
 208 void EVENT_USB_UnhandledControlPacket(void)
 209 {
 210         Audio_Device_ProcessControlPacket(&Speaker_Audio_Interface);
 211 }