Demos/Device/ClassDriver/AudioOutput/AudioOutput.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2010  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   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, convert to 8-bit */
  99                 int8_t  LeftSample_8Bit   = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
 100                 int8_t  RightSample_8Bit  = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
 101
 102                 /* Mix the two channels together to produce a mono, 8-bit sample */
 103                 int8_t  MixedSample_8Bit  = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
 104
 105 #if defined(AUDIO_OUT_MONO)
 106                 /* Load the sample into the PWM timer channel */
 107                 OCR3A = (MixedSample_8Bit ^ (1 << 7));
 108 #elif defined(AUDIO_OUT_STEREO)
 109                 /* Load the dual 8-bit samples into the PWM timer channels */
 110                 OCR3A = (LeftSample_8Bit  ^ (1 << 7));
 111                 OCR3B = (RightSample_8Bit ^ (1 << 7));
 112 #elif defined(AUDIO_OUT_PORTC)
 113                 /* Load the 8-bit mixed sample into PORTC */
 114                 PORTC = MixedSample_8Bit;
 115 #endif
 116
 117                 uint8_t LEDMask = LEDS_NO_LEDS;
 118
 119                 /* Turn on LEDs as the sample amplitude increases */
 120                 if (MixedSample_8Bit > 16)
 121                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3 | LEDS_LED4);
 122                 else if (MixedSample_8Bit > 8)
 123                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3);
 124                 else if (MixedSample_8Bit > 4)
 125                   LEDMask = (LEDS_LED1 | LEDS_LED2);
 126                 else if (MixedSample_8Bit > 2)
 127                   LEDMask = (LEDS_LED1);
 128
 129                 LEDs_SetAllLEDs(LEDMask);
 130         }
 131 }
 132
 133 /** Event handler for the library USB Connection event. */
 134 void EVENT_USB_Device_Connect(void)
 135 {
 136         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 137
 138         /* Sample reload timer initialization */
 139         OCR0A   = (F_CPU / 8 / AUDIO_SAMPLE_FREQUENCY) - 1;
 140         TCCR0A  = (1 << WGM01);  // CTC mode
 141         TCCR0B  = (1 << CS01);   // Fcpu/8 speed
 142
 143 #if defined(AUDIO_OUT_MONO)
 144         /* Set speaker as output */
 145         DDRC   |= (1 << 6);
 146 #elif defined(AUDIO_OUT_STEREO)
 147         /* Set speakers as outputs */
 148         DDRC   |= ((1 << 6) | (1 << 5));
 149 #elif defined(AUDIO_OUT_PORTC)
 150         /* Set PORTC as outputs */
 151         DDRC   |= 0xFF;
 152 #endif
 153
 154 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 155         /* PWM speaker timer initialization */
 156         TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
 157                 | (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
 158         TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, Fcpu speed
 159 #endif
 160 }
 161
 162 /** Event handler for the library USB Disconnection event. */
 163 void EVENT_USB_Device_Disconnect(void)
 164 {
 165         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 166
 167         /* Stop the sample reload timer */
 168         TCCR0B = 0;
 169
 170 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 171         /* Stop the PWM generation timer */
 172         TCCR3B = 0;
 173 #endif
 174
 175 #if defined(AUDIO_OUT_MONO)
 176         /* Set speaker as input to reduce current draw */
 177         DDRC   &= ~(1 << 6);
 178 #elif defined(AUDIO_OUT_STEREO)
 179         /* Set speakers as inputs to reduce current draw */
 180         DDRC   &= ~((1 << 6) | (1 << 5));
 181 #elif defined(AUDIO_OUT_PORTC)
 182         /* Set PORTC low */
 183         PORTC  = 0x00;
 184 #endif
 185 }
 186
 187 /** Event handler for the library USB Configuration Changed event. */
 188 void EVENT_USB_Device_ConfigurationChanged(void)
 189 {
 190         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 191
 192         if (!(Audio_Device_ConfigureEndpoints(&Speaker_Audio_Interface)))
 193           LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 194 }
 195
 196 /** Event handler for the library USB Unhandled Control Request event. */
 197 void EVENT_USB_Device_UnhandledControlRequest(void)
 198 {
 199         Audio_Device_ProcessControlRequest(&Speaker_Audio_Interface);
 200 }