Demos/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 /** \file
  32  *
  33  *  Main source file for the Audio Input demo. This file contains the main tasks of the demo and
  34  *  is responsible for the initial application hardware configuration.
  35  */
  36
  37 /* ---  Project Configuration  --- */
  38 //#define MICROPHONE_BIASED_TO_HALF_RAIL
  39 /* --- --- --- --- --- --- --- --- */
  40
  41 #include "AudioInput.h"
  42
  43 /* Project Tags, for reading out using the ButtLoad project */
  44 BUTTLOADTAG(ProjName,    "LUFA AudioIn App");
  45 BUTTLOADTAG(BuildTime,   __TIME__);
  46 BUTTLOADTAG(BuildDate,   __DATE__);
  47 BUTTLOADTAG(LUFAVersion, "LUFA V" LUFA_VERSION_STRING);
  48
  49 /* Scheduler Task List */
  50 TASK_LIST
  51 {
  52         { Task: USB_USBTask          , TaskStatus: TASK_STOP },
  53         { Task: USB_Audio_Task       , TaskStatus: TASK_STOP },
  54 };
  55
  56
  57 /** Main program entry point. This routine configures the hardware required by the application, then
  58  *  starts the scheduler to run the application tasks.
  59  */
  60 int main(void)
  61 {
  62         /* Disable watchdog if enabled by bootloader/fuses */
  63         MCUSR &= ~(1 << WDRF);
  64         wdt_disable();
  65
  66         /* Disable clock division */
  67         clock_prescale_set(clock_div_1);
  68
  69         /* Hardware Initialization */
  70         LEDs_Init();
  71         ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32);
  72         ADC_SetupChannel(MIC_IN_ADC_CHANNEL);
  73
  74         /* Start the ADC conversion in free running mode */
  75         ADC_StartReading(ADC_REFERENCE_AVCC | ADC_RIGHT_ADJUSTED | MIC_IN_ADC_CHANNEL);
  76
  77         /* Indicate USB not ready */
  78         UpdateStatus(Status_USBNotReady);
  79
  80         /* Initialize Scheduler so that it can be used */
  81         Scheduler_Init();
  82
  83         /* Initialize USB Subsystem */
  84         USB_Init();
  85
  86         /* Scheduling - routine never returns, so put this last in the main function */
  87         Scheduler_Start();
  88 }
  89
  90 /** Event handler for the USB_Connect event. This indicates that the device is enumerating via the status LEDs, and
  91  *  configures the sample update and PWM timers.
  92  */
  93 EVENT_HANDLER(USB_Connect)
  94 {
  95         /* Start USB management task */
  96         Scheduler_SetTaskMode(USB_USBTask, TASK_RUN);
  97
  98         /* Indicate USB enumerating */
  99         UpdateStatus(Status_USBEnumerating);
 100
 101         /* Sample reload timer initialization */
 102         OCR0A   = (F_CPU / AUDIO_SAMPLE_FREQUENCY);
 103         TCCR0A  = (1 << WGM01);  // CTC mode
 104         TCCR0B  = (1 << CS00);   // Fcpu speed
 105 }
 106
 107 /** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via
 108  *  the status LEDs, disables the sample update and PWM output timers and stops the USB and Audio management tasks.
 109  */
 110 EVENT_HANDLER(USB_Disconnect)
 111 {
 112         /* Stop the sample reload timer */
 113         TCCR0B = 0;
 114
 115         /* Stop running audio and USB management tasks */
 116         Scheduler_SetTaskMode(USB_Audio_Task, TASK_STOP);
 117         Scheduler_SetTaskMode(USB_USBTask, TASK_STOP);
 118
 119         /* Indicate USB not ready */
 120         UpdateStatus(Status_USBNotReady);
 121 }
 122
 123 /** Event handler for the USB_ConfigurationChanged event. This is fired when the host set the current configuration
 124  *  of the USB device after enumeration - the device endpoints are configured.
 125  */
 126 EVENT_HANDLER(USB_ConfigurationChanged)
 127 {
 128         /* Setup audio stream endpoint */
 129         Endpoint_ConfigureEndpoint(AUDIO_STREAM_EPNUM, EP_TYPE_ISOCHRONOUS,
 130                                        ENDPOINT_DIR_IN, AUDIO_STREAM_EPSIZE,
 131                                    ENDPOINT_BANK_DOUBLE);
 132
 133         /* Indicate USB connected and ready */
 134         UpdateStatus(Status_USBReady);
 135 }
 136
 137 /** Event handler for the USB_UnhandledControlPacket event. This is used to catch standard and class specific
 138  *  control requests that are not handled internally by the USB library (including the Audio class-specific
 139  *  requests) so that they can be handled appropriately for the application.
 140  */
 141 EVENT_HANDLER(USB_UnhandledControlPacket)
 142 {
 143         /* Process General and Audio specific control requests */
 144         switch (bRequest)
 145         {
 146                 case REQ_SetInterface:
 147                         /* Set Interface is not handled by the library, as its function is application-specific */
 148                         if (bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_STANDARD | REQREC_INTERFACE))
 149                         {
 150                                 uint16_t wValue = Endpoint_Read_Word_LE();
 151
 152                                 Endpoint_ClearSetupReceived();
 153
 154                                 /* Check if the host is enabling the audio interface (setting AlternateSetting to 1) */
 155                                 if (wValue)
 156                                 {
 157                                         /* Start audio task */
 158                                         Scheduler_SetTaskMode(USB_Audio_Task, TASK_RUN);
 159                                 }
 160                                 else
 161                                 {
 162                                         /* Stop audio task */
 163                                         Scheduler_SetTaskMode(USB_Audio_Task, TASK_STOP);
 164                                 }
 165
 166                                 /* Acknowledge status stage */
 167                                 while (!(Endpoint_IsSetupINReady()));
 168                                 Endpoint_ClearSetupIN();
 169                         }
 170
 171                         break;
 172         }
 173 }
 174
 175 /** Function to manage status updates to the user. This is done via LEDs on the given board, if available, but may be changed to
 176  *  log to a serial port, or anything else that is suitable for status updates.
 177  *
 178  *  \param CurrentStatus  Current status of the system, from the AudioInput_StatusCodes_t enum
 179  */
 180 void UpdateStatus(uint8_t CurrentStatus)
 181 {
 182         uint8_t LEDMask = LEDS_NO_LEDS;
 183
 184         /* Set the LED mask to the appropriate LED mask based on the given status code */
 185         switch (CurrentStatus)
 186         {
 187                 case Status_USBNotReady:
 188                         LEDMask = (LEDS_LED1);
 189                         break;
 190                 case Status_USBEnumerating:
 191                         LEDMask = (LEDS_LED1 | LEDS_LED2);
 192                         break;
 193                 case Status_USBReady:
 194                         LEDMask = (LEDS_LED2 | LEDS_LED4);
 195                         break;
 196         }
 197
 198         /* Set the board LEDs to the new LED mask */
 199         LEDs_SetAllLEDs(LEDMask);
 200 }
 201
 202 /** Task to manage the Audio interface, reading in ADC samples from the microphone, and them to the host. */
 203 TASK(USB_Audio_Task)
 204 {
 205         /* Select the audio stream endpoint */
 206         Endpoint_SelectEndpoint(AUDIO_STREAM_EPNUM);
 207
 208         /* Check if the current endpoint can be read from (contains a packet) and that the next sample should be stored */
 209         if (Endpoint_ReadWriteAllowed() && (TIFR0 & (1 << OCF0A)))
 210         {
 211                 /* Clear the sample reload timer */
 212                 TIFR0 |= (1 << OCF0A);
 213
 214                 /* Audio sample is ADC value scaled to fit the entire range */
 215                 int16_t AudioSample = ((SAMPLE_MAX_RANGE / ADC_MAX_RANGE) * ADC_GetResult());
 216
 217 #if defined(MICROPHONE_BIASED_TO_HALF_RAIL)
 218                 /* Microphone is biased to half rail voltage, subtract the bias from the sample value */
 219                 AudioSample -= (SAMPLE_MAX_RANGE / 2));
 220 #endif
 221
 222                 /* Write the sample to the buffer */
 223                 Endpoint_Write_Word_LE(AudioSample);
 224
 225                 /* Check to see if the bank is now full */
 226                 if (!(Endpoint_ReadWriteAllowed()))
 227                 {
 228                         /* Send the full packet to the host */
 229                         Endpoint_ClearCurrentBank();
 230                 }
 231         }
 232 }