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