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                 /* Mix the two channels together to produce a mono, 8-bit sample */
 107                 int8_t  MixedSample_8Bit  = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
 108
 109                 /* Get absolute value of mixed sample value */
 110                 uint8_t MixedSample_8Bit_Abs = abs(MixedSample_8Bit);
 111
 112 #if defined(AUDIO_OUT_MONO)
 113                 /* Load the sample into the PWM timer channel */
 114                 OCR3A = ((uint8_t)MixedSample_8Bit ^ (1 << 7));
 115 #elif defined(AUDIO_OUT_STEREO)
 116                 /* Load the dual 8-bit samples into the PWM timer channels */
 117                 OCR3A = ((uint8_t)LeftSample_8Bit  ^ (1 << 7));
 118                 OCR3B = ((uint8_t)RightSample_8Bit ^ (1 << 7));
 119 #elif defined(AUDIO_OUT_PORTC)
 120                 /* Load the 8-bit mixed sample into PORTC */
 121                 PORTC = MixedSample_8Bit;
 122 #endif
 123
 124                 uint8_t LEDMask = LEDS_NO_LEDS;
 125
 126                 /* Turn on LEDs as the sample amplitude increases */
 127                 if (MixedSample_8Bit_Abs > 16)
 128                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3 | LEDS_LED4);
 129                 else if (MixedSample_8Bit_Abs > 8)
 130                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3);
 131                 else if (MixedSample_8Bit_Abs > 4)
 132                   LEDMask = (LEDS_LED1 | LEDS_LED2);
 133                 else if (MixedSample_8Bit_Abs > 2)
 134                   LEDMask = (LEDS_LED1);
 135
 136                 LEDs_SetAllLEDs(LEDMask);
 137         }
 138 }
 139
 140 /** Event handler for the library USB Connection event. */
 141 void EVENT_USB_Device_Connect(void)
 142 {
 143         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 144
 145         /* Sample reload timer initialization */
 146         OCR0A   = (F_CPU / AUDIO_SAMPLE_FREQUENCY) - 1;
 147         TCCR0A  = (1 << WGM01);  // CTC mode
 148         TCCR0B  = (1 << CS00);   // Fcpu speed
 149
 150 #if defined(AUDIO_OUT_MONO)
 151         /* Set speaker as output */
 152         DDRC   |= (1 << 6);
 153 #elif defined(AUDIO_OUT_STEREO)
 154         /* Set speakers as outputs */
 155         DDRC   |= ((1 << 6) | (1 << 5));
 156 #elif defined(AUDIO_OUT_PORTC)
 157         /* Set PORTC as outputs */
 158         DDRC   |= 0xFF;
 159 #endif
 160
 161 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 162         /* PWM speaker timer initialization */
 163         TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
 164                 | (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
 165         TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, Fcpu speed
 166 #endif
 167 }
 168
 169 /** Event handler for the library USB Disconnection event. */
 170 void EVENT_USB_Device_Disconnect(void)
 171 {
 172         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 173
 174         /* Stop the sample reload timer */
 175         TCCR0B = 0;
 176
 177 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 178         /* Stop the PWM generation timer */
 179         TCCR3B = 0;
 180 #endif
 181
 182 #if defined(AUDIO_OUT_MONO)
 183         /* Set speaker as input to reduce current draw */
 184         DDRC   &= ~(1 << 6);
 185 #elif defined(AUDIO_OUT_STEREO)
 186         /* Set speakers as inputs to reduce current draw */
 187         DDRC   &= ~((1 << 6) | (1 << 5));
 188 #elif defined(AUDIO_OUT_PORTC)
 189         /* Set PORTC low */
 190         PORTC  = 0x00;
 191 #endif
 192 }
 193
 194 /** Event handler for the library USB Configuration Changed event. */
 195 void EVENT_USB_Device_ConfigurationChanged(void)
 196 {
 197         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 198
 199         if (!(Audio_Device_ConfigureEndpoints(&Speaker_Audio_Interface)))
 200           LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 201 }
 202
 203 /** Event handler for the library USB Unhandled Control Request event. */
 204 void EVENT_USB_Device_UnhandledControlRequest(void)
 205 {
 206         Audio_Device_ProcessControlRequest(&Speaker_Audio_Interface);
 207 }