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         sei();
  63
  64         for (;;)
  65         {
  66                 ProcessNextSample();
  67
  68                 Audio_Device_USBTask(&Speaker_Audio_Interface);
  69                 USB_USBTask();
  70         }
  71 }
  72
  73 /** Configures the board hardware and chip peripherals for the demo's functionality. */
  74 void SetupHardware(void)
  75 {
  76         /* Disable watchdog if enabled by bootloader/fuses */
  77         MCUSR &= ~(1 << WDRF);
  78         wdt_disable();
  79
  80         /* Disable clock division */
  81         clock_prescale_set(clock_div_1);
  82
  83         /* Hardware Initialization */
  84         LEDs_Init();
  85         USB_Init();
  86 }
  87
  88 /** Processes the next audio sample by reading the last ADC conversion and writing it to the audio
  89  *  interface, each time the sample reload timer period elapses to give a constant sample rate.
  90  */
  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                 /* Clear the sample reload timer compare flag, ready for the next interval */
  97                 TIFR0 |= (1 << OCF0A);
  98
  99                 /* Retrieve the signed 16-bit left and right audio samples, convert to 8-bit */
 100                 int8_t  LeftSample_8Bit   = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
 101                 int8_t  RightSample_8Bit  = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
 102
 103                 /* Mix the two channels together to produce a mono, 8-bit sample */
 104                 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 #elif defined(AUDIO_OUT_STEREO)
 110                 /* Load the dual 8-bit samples into the PWM timer channels */
 111                 OCR3A = (LeftSample_8Bit  ^ (1 << 7));
 112                 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                 LEDs_SetAllLEDs(LEDMask);
 131         }
 132 }
 133
 134 /** Event handler for the library USB Connection event. */
 135 void EVENT_USB_Device_Connect(void)
 136 {
 137         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 138
 139         /* 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 #if defined(AUDIO_OUT_MONO)
 145         /* Set speaker as output */
 146         DDRC   |= (1 << 6);
 147 #elif defined(AUDIO_OUT_STEREO)
 148         /* Set speakers as outputs */
 149         DDRC   |= ((1 << 6) | (1 << 5));
 150 #elif defined(AUDIO_OUT_PORTC)
 151         /* Set PORTC as outputs */
 152         DDRC   |= 0xFF;
 153 #endif
 154
 155 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 156         /* PWM speaker timer initialization */
 157         TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
 158                 | (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
 159         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         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 167
 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 #if defined(AUDIO_OUT_MONO)
 177         /* Set speaker as input to reduce current draw */
 178         DDRC   &= ~(1 << 6);
 179 #elif defined(AUDIO_OUT_STEREO)
 180         /* Set speakers as inputs to reduce current draw */
 181         DDRC   &= ~((1 << 6) | (1 << 5));
 182 #elif defined(AUDIO_OUT_PORTC)
 183         /* Set PORTC low */
 184         PORTC  = 0x00;
 185 #endif
 186 }
 187
 188 /** Event handler for the library USB Configuration Changed event. */
 189 void EVENT_USB_Device_ConfigurationChanged(void)
 190 {
 191         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 192
 193         if (!(Audio_Device_ConfigureEndpoints(&Speaker_Audio_Interface)))
 194           LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 195 }
 196
 197 /** Event handler for the library USB Unhandled Control Request event. */
 198 void EVENT_USB_Device_UnhandledControlRequest(void)
 199 {
 200         Audio_Device_ProcessControlRequest(&Speaker_Audio_Interface);
 201 }