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 /** 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                 Audio_Device_USBTask(&Microphone_Audio_Interface);
  67                 USB_USBTask();
  68         }
  69 }
  70
  71 /** Configures the board hardware and chip peripherals for the demo's functionality. */
  72 void SetupHardware(void)
  73 {
  74         /* Disable watchdog if enabled by bootloader/fuses */
  75         MCUSR &= ~(1 << WDRF);
  76         wdt_disable();
  77
  78         /* Disable clock division */
  79         clock_prescale_set(clock_div_1);
  80
  81         /* Hardware Initialization */
  82         LEDs_Init();
  83         Buttons_Init();
  84         ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32);
  85         ADC_SetupChannel(MIC_IN_ADC_CHANNEL);
  86         USB_Init();
  87
  88         /* Start the ADC conversion in free running mode */
  89         ADC_StartReading(ADC_REFERENCE_AVCC | ADC_RIGHT_ADJUSTED | MIC_IN_ADC_MUX_MASK);
  90 }
  91
  92 /** ISR to handle the reloading of the data endpoint with the next sample. */
  93 ISR(TIMER0_COMPA_vect, ISR_BLOCK)
  94 {
  95         uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint();
  96
  97         /* Check if the sample reload timer period has elapsed, and that the USB bus is ready for a new sample */
  98         if (Audio_Device_IsReadyForNextSample(&Microphone_Audio_Interface))
  99         {
 100                 int16_t AudioSample;
 101
 102                 #if defined(USE_TEST_TONE)
 103                         static uint8_t SquareWaveSampleCount;
 104                         static int16_t CurrentWaveValue;
 105
 106                         /* In test tone mode, generate a square wave at 1/256 of the sample rate */
 107                         if (SquareWaveSampleCount++ == 0xFF)
 108                           CurrentWaveValue ^= 0x8000;
 109
 110                         /* Only generate audio if the board button is being pressed */
 111                         AudioSample = (Buttons_GetStatus() & BUTTONS_BUTTON1) ? CurrentWaveValue : 0;
 112                 #else
 113                         /* Audio sample is ADC value scaled to fit the entire range */
 114                         AudioSample = ((SAMPLE_MAX_RANGE / ADC_MAX_RANGE) * ADC_GetResult());
 115
 116                         #if defined(MICROPHONE_BIASED_TO_HALF_RAIL)
 117                         /* Microphone is biased to half rail voltage, subtract the bias from the sample value */
 118                         AudioSample -= (SAMPLE_MAX_RANGE / 2);
 119                         #endif
 120                 #endif
 121
 122                 Audio_Device_WriteSample16(&Microphone_Audio_Interface, AudioSample);
 123         }
 124
 125         Endpoint_SelectEndpoint(PrevEndpoint);
 126 }
 127
 128 /** Event handler for the library USB Connection event. */
 129 void EVENT_USB_Device_Connect(void)
 130 {
 131         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 132
 133         /* Sample reload timer initialization */
 134         TIMSK0  = (1 << OCIE0A);
 135         OCR0A   = ((F_CPU / 8 / AUDIO_SAMPLE_FREQUENCY) - 1);
 136         TCCR0A  = (1 << WGM01);  // CTC mode
 137         TCCR0B  = (1 << CS01);   // Fcpu/8 speed
 138 }
 139
 140 /** Event handler for the library USB Disconnection event. */
 141 void EVENT_USB_Device_Disconnect(void)
 142 {
 143         /* Stop the sample reload timer */
 144         TCCR0B = 0;
 145
 146         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 147 }
 148
 149 /** Event handler for the library USB Configuration Changed event. */
 150 void EVENT_USB_Device_ConfigurationChanged(void)
 151 {
 152         bool ConfigSuccess = true;
 153
 154         ConfigSuccess &= Audio_Device_ConfigureEndpoints(&Microphone_Audio_Interface);
 155
 156         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 157 }
 158
 159 /** Event handler for the library USB Control Request reception event. */
 160 void EVENT_USB_Device_ControlRequest(void)
 161 {
 162         Audio_Device_ProcessControlRequest(&Microphone_Audio_Interface);
 163 }
 164