Demos/Device/ClassDriver/AudioInput/AudioInput.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2011.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2011  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 AudioInput demo. This file contains the main tasks of
  34  *  the demo and is responsible for the initial application hardware configuration.
  35  */
  36
  37 #include "AudioInput.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 Microphone_Audio_Interface =
  44         {
  45                 .Config =
  46                         {
  47                                 .StreamingInterfaceNumber = 1,
  48
  49                                 .DataINEndpointNumber     = AUDIO_STREAM_EPNUM,
  50                                 .DataINEndpointSize       = AUDIO_STREAM_EPSIZE,
  51                         },
  52         };
  53
  54
  55 /** Main program entry point. This routine contains the overall program flow, including initial
  56  *  setup of all components and the main program loop.
  57  */
  58 int main(void)
  59 {
  60         SetupHardware();
  61
  62         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  63         sei();
  64
  65         for (;;)
  66         {
  67                 Audio_Device_USBTask(&Microphone_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         Buttons_Init();
  85         ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32);
  86         ADC_SetupChannel(MIC_IN_ADC_CHANNEL);
  87         USB_Init();
  88
  89         /* Start the ADC conversion in free running mode */
  90         ADC_StartReading(ADC_REFERENCE_AVCC | ADC_RIGHT_ADJUSTED | MIC_IN_ADC_MUX_MASK);
  91 }
  92
  93 /** ISR to handle the reloading of the data endpoint with the next sample. */
  94 ISR(TIMER0_COMPA_vect, ISR_BLOCK)
  95 {
  96         uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint();
  97
  98         /* Check if the sample reload timer period has elapsed, and that the USB bus is ready for a new sample */
  99         if (Audio_Device_IsReadyForNextSample(&Microphone_Audio_Interface))
 100         {
 101                 int16_t AudioSample;
 102
 103                 #if defined(USE_TEST_TONE)
 104                         static uint8_t SquareWaveSampleCount;
 105                         static int16_t CurrentWaveValue;
 106
 107                         /* In test tone mode, generate a square wave at 1/256 of the sample rate */
 108                         if (SquareWaveSampleCount++ == 0xFF)
 109                           CurrentWaveValue ^= 0x8000;
 110
 111                         /* Only generate audio if the board button is being pressed */
 112                         AudioSample = (Buttons_GetStatus() & BUTTONS_BUTTON1) ? CurrentWaveValue : 0;
 113                 #else
 114                         /* Audio sample is ADC value scaled to fit the entire range */
 115                         AudioSample = ((SAMPLE_MAX_RANGE / ADC_MAX_RANGE) * ADC_GetResult());
 116
 117                         #if defined(MICROPHONE_BIASED_TO_HALF_RAIL)
 118                         /* Microphone is biased to half rail voltage, subtract the bias from the sample value */
 119                         AudioSample -= (SAMPLE_MAX_RANGE / 2);
 120                         #endif
 121                 #endif
 122
 123                 Audio_Device_WriteSample16(&Microphone_Audio_Interface, AudioSample);
 124         }
 125
 126         Endpoint_SelectEndpoint(PrevEndpoint);
 127 }
 128
 129 /** Event handler for the library USB Connection event. */
 130 void EVENT_USB_Device_Connect(void)
 131 {
 132         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 133
 134         /* Sample reload timer initialization */
 135         TIMSK0  = (1 << OCIE0A);
 136         OCR0A   = ((F_CPU / 8 / AUDIO_SAMPLE_FREQUENCY) - 1);
 137         TCCR0A  = (1 << WGM01);  // CTC mode
 138         TCCR0B  = (1 << CS01);   // Fcpu/8 speed
 139 }
 140
 141 /** Event handler for the library USB Disconnection event. */
 142 void EVENT_USB_Device_Disconnect(void)
 143 {
 144         /* Stop the sample reload timer */
 145         TCCR0B = 0;
 146
 147         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 148 }
 149
 150 /** Event handler for the library USB Configuration Changed event. */
 151 void EVENT_USB_Device_ConfigurationChanged(void)
 152 {
 153         bool ConfigSuccess = true;
 154
 155         ConfigSuccess &= Audio_Device_ConfigureEndpoints(&Microphone_Audio_Interface);
 156
 157         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 158 }
 159
 160 /** Event handler for the library USB Control Request reception event. */
 161 void EVENT_USB_Device_ControlRequest(void)
 162 {
 163         Audio_Device_ProcessControlRequest(&Microphone_Audio_Interface);
 164 }
 165