Demos/Device/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 #include "AudioOutput.h"
  32
  33 USB_ClassInfo_Audio_t Speaker_Audio_Interface =
  34         {
  35                 .InterfaceNumber       = 0,
  36
  37                 .DataOUTEndpointNumber = AUDIO_STREAM_EPNUM,
  38                 .DataOUTEndpointSize   = AUDIO_STREAM_EPSIZE,
  39         };
  40
  41 int main(void)
  42 {
  43         SetupHardware();
  44
  45         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  46
  47         for (;;)
  48         {
  49                 if (Speaker_Audio_Interface.InterfaceEnabled)
  50                   ProcessNextSample();
  51
  52                 USB_USBTask();
  53         }
  54 }
  55
  56 void SetupHardware(void)
  57 {
  58         /* Disable watchdog if enabled by bootloader/fuses */
  59         MCUSR &= ~(1 << WDRF);
  60         wdt_disable();
  61
  62         /* Disable clock division */
  63         clock_prescale_set(clock_div_1);
  64
  65         /* Hardware Initialization */
  66         LEDs_Init();
  67         USB_Init();
  68 }
  69
  70 void ProcessNextSample(void)
  71 {
  72         if ((TIFR0 & (1 << OCF0A)) && USB_Audio_IsSampleReceived(&Speaker_Audio_Interface))
  73         {
  74                 /* Clear the sample reload timer */
  75                 TIFR0 |= (1 << OCF0A);
  76
  77                 /* Retrieve the signed 16-bit left and right audio samples */
  78                 int16_t LeftSample_16Bit  = (int16_t)USB_Audio_ReadSample16();
  79                 int16_t RightSample_16Bit = (int16_t)USB_Audio_ReadSample16();
  80
  81                 /* Massage signed 16-bit left and right audio samples into signed 8-bit */
  82                 int8_t  LeftSample_8Bit   = (LeftSample_16Bit  >> 8);
  83                 int8_t  RightSample_8Bit  = (RightSample_16Bit >> 8);
  84
  85 #if defined(AUDIO_OUT_MONO)
  86                 /* Mix the two channels together to produce a mono, 8-bit sample */
  87                 int8_t  MixedSample_8Bit  = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
  88
  89                 /* Load the sample into the PWM timer channel */
  90                 OCRxA = ((uint8_t)MixedSample_8Bit ^ (1 << 7));
  91 #elif defined(AUDIO_OUT_STEREO)
  92                 /* Load the dual 8-bit samples into the PWM timer channels */
  93                 OCRxA = ((uint8_t)LeftSample_8Bit  ^ (1 << 7));
  94                 OCRxB = ((uint8_t)RightSample_8Bit ^ (1 << 7));
  95 #elif defined(AUDIO_OUT_PORTC)
  96                 /* Mix the two channels together to produce a mono, 8-bit sample */
  97                 int8_t  MixedSample_8Bit  = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
  98
  99                 PORTC = MixedSample_8Bit;
 100 #else
 101                 uint8_t LEDMask = LEDS_NO_LEDS;
 102
 103                 /* Make left channel positive (absolute) */
 104                 if (LeftSample_8Bit < 0)
 105                   LeftSample_8Bit = -LeftSample_8Bit;
 106
 107                 /* Make right channel positive (absolute) */
 108                 if (RightSample_8Bit < 0)
 109                   RightSample_8Bit = -RightSample_8Bit;
 110
 111                 /* Set first LED based on sample value */
 112                 if (LeftSample_8Bit < ((128 / 8) * 1))
 113                   LEDMask |= LEDS_LED2;
 114                 else if (LeftSample_8Bit < ((128 / 8) * 3))
 115                   LEDMask |= (LEDS_LED1 | LEDS_LED2);
 116                 else
 117                   LEDMask |= LEDS_LED1;
 118
 119                 /* Set second LED based on sample value */
 120                 if (RightSample_8Bit < ((128 / 8) * 1))
 121                   LEDMask |= LEDS_LED4;
 122                 else if (RightSample_8Bit < ((128 / 8) * 3))
 123                   LEDMask |= (LEDS_LED3 | LEDS_LED4);
 124                 else
 125                   LEDMask |= LEDS_LED3;
 126
 127                 LEDs_SetAllLEDs(LEDMask);
 128 #endif
 129         }
 130 }
 131
 132 void EVENT_USB_Connect(void)
 133 {
 134         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 135
 136         /* Sample reload timer initialization */
 137         OCR0A   = (F_CPU / AUDIO_SAMPLE_FREQUENCY) - 1;
 138         TCCR0A  = (1 << WGM01);  // CTC mode
 139         TCCR0B  = (1 << CS00);   // Fcpu speed
 140
 141 #if defined(AUDIO_OUT_MONO)
 142         /* Set speaker as output */
 143         DDRC   |= (1 << 6);
 144 #elif defined(AUDIO_OUT_STEREO)
 145         /* Set speakers as outputs */
 146         DDRC   |= ((1 << 6) | (1 << 5));
 147 #elif defined(AUDIO_OUT_PORTC)
 148         /* Set PORTC as outputs */
 149         DDRC   |= 0xFF;
 150 #endif
 151
 152 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 153         /* PWM speaker timer initialization */
 154         TCCRxA  = ((1 << WGMx0) | (1 << COMxA1) | (1 << COMxA0)
 155                                                         | (1 << COMxB1) | (1 << COMxB0)); // Set on match, clear on TOP
 156         TCCRxB  = ((1 << WGMx2) | (1 << CSx0));  // Fast 8-Bit PWM, Fcpu speed
 157 #endif
 158 }
 159
 160 /** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via
 161  *  the status LEDs, disables the sample update and PWM output timers and stops the USB and Audio management tasks.
 162  */
 163 void EVENT_USB_Disconnect(void)
 164 {
 165         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 166
 167         /* Stop the timers */
 168         TCCR0B = 0;
 169 #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 170         TCCRxB = 0;
 171 #endif
 172
 173 #if defined(AUDIO_OUT_MONO)
 174         /* Set speaker as input to reduce current draw */
 175         DDRC   &= ~(1 << 6);
 176 #elif defined(AUDIO_OUT_STEREO)
 177         /* Set speakers as inputs to reduce current draw */
 178         DDRC   &= ~((1 << 6) | (1 << 5));
 179 #elif defined(AUDIO_OUT_PORTC)
 180         /* Set PORTC low */
 181         PORTC  = 0x00;
 182 #endif
 183 }
 184
 185 void EVENT_USB_ConfigurationChanged(void)
 186 {
 187         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 188
 189         if (!(USB_Audio_ConfigureEndpoints(&Speaker_Audio_Interface)))
 190           LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 191 }
 192
 193 void EVENT_USB_UnhandledControlPacket(void)
 194 {
 195         USB_Audio_ProcessControlPacket(&Speaker_Audio_Interface);
 196 }