Demos/Device/AudioInput/AudioInput.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 "AudioInput.h"
  32
  33 USB_ClassInfo_Audio_t Microphone_Audio_Interface =
  34         {
  35                 .InterfaceNumber      = 0,
  36
  37                 .DataINEndpointNumber = AUDIO_STREAM_EPNUM,
  38                 .DataINEndpointSize   = 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 (Microphone_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         ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32);
  69         ADC_SetupChannel(MIC_IN_ADC_CHANNEL);
  70
  71         /* Start the ADC conversion in free running mode */
  72         ADC_StartReading(ADC_REFERENCE_AVCC | ADC_RIGHT_ADJUSTED | MIC_IN_ADC_CHANNEL);
  73 }
  74
  75 void ProcessNextSample(void)
  76 {
  77         if ((TIFR0 & (1 << OCF0A)) && USB_Audio_IsReadyForNextSample(&Microphone_Audio_Interface))
  78         {
  79                 TIFR0 |= (1 << OCF0A);
  80
  81                 /* Audio sample is ADC value scaled to fit the entire range */
  82                 int16_t AudioSample = ((SAMPLE_MAX_RANGE / ADC_MAX_RANGE) * ADC_GetResult());
  83
  84 #if defined(MICROPHONE_BIASED_TO_HALF_RAIL)
  85                 /* Microphone is biased to half rail voltage, subtract the bias from the sample value */
  86                 AudioSample -= (SAMPLE_MAX_RANGE / 2));
  87 #endif
  88
  89                 USB_Audio_WriteSample16(AudioSample);
  90         }
  91 }
  92
  93 void EVENT_USB_Connect(void)
  94 {
  95         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
  96
  97         /* Sample reload timer initialization */
  98         OCR0A   = (F_CPU / AUDIO_SAMPLE_FREQUENCY) - 1;
  99         TCCR0A  = (1 << WGM01);  // CTC mode
 100         TCCR0B  = (1 << CS00);   // Fcpu speed
 101 }
 102
 103 void EVENT_USB_Disconnect(void)
 104 {
 105         /* Stop the sample reload timer */
 106         TCCR0B = 0;
 107
 108         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 109 }
 110
 111 void EVENT_USB_ConfigurationChanged(void)
 112 {
 113         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 114
 115         if (!(USB_Audio_ConfigureEndpoints(&Microphone_Audio_Interface)))
 116           LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 117 }
 118
 119 void EVENT_USB_UnhandledControlPacket(void)
 120 {
 121         USB_Audio_ProcessControlPacket(&Microphone_Audio_Interface);
 122 }