Demos/Device/ClassDriver/AudioOutput/AudioOutput.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 AudioOutput demo. This file contains the main tasks of
  34  *  the demo and is responsible for the initial application hardware configuration.
  35  */
  36
  37 #include "AudioOutput.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 Speaker_Audio_Interface =
  44         {
  45                 .Config =
  46                         {
  47                                 .StreamingInterfaceNumber = 1,
  48
  49                                 .DataOUTEndpointNumber    = AUDIO_STREAM_EPNUM,
  50                                 .DataOUTEndpointSize      = AUDIO_STREAM_EPSIZE,
  51                         },
  52         };
  53
  54 /** Current audio sampling frequency of the streaming audio endpoint. */
  55 static uint32_t CurrentAudioSampleFrequency = 48000;
  56
  57
  58 /** Main program entry point. This routine contains the overall program flow, including initial
  59  *  setup of all components and the main program loop.
  60  */
  61 int main(void)
  62 {
  63         SetupHardware();
  64
  65         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  66         sei();
  67
  68         for (;;)
  69         {
  70                 Audio_Device_USBTask(&Speaker_Audio_Interface);
  71                 USB_USBTask();
  72         }
  73 }
  74
  75 /** Configures the board hardware and chip peripherals for the demo's functionality. */
  76 void SetupHardware(void)
  77 {
  78         /* Disable watchdog if enabled by bootloader/fuses */
  79         MCUSR &= ~(1 << WDRF);
  80         wdt_disable();
  81
  82         /* Disable clock division */
  83         clock_prescale_set(clock_div_1);
  84
  85         /* Hardware Initialization */
  86         LEDs_Init();
  87         USB_Init();
  88 }
  89
  90 /** ISR to handle the reloading of the PWM timer with the next sample. */
  91 ISR(TIMER0_COMPA_vect, ISR_BLOCK)
  92 {
  93         uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint();
  94
  95         /* Check that the USB bus is ready for the next sample to read */
  96         if (Audio_Device_IsSampleReceived(&Speaker_Audio_Interface))
  97         {
  98                 /* Retrieve the signed 16-bit left and right audio samples, convert to 8-bit */
  99                 int8_t LeftSample_8Bit  = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
 100                 int8_t RightSample_8Bit = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
 101
 102                 /* Mix the two channels together to produce a mono, 8-bit sample */
 103                 int8_t MixedSample_8Bit = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
 104
 105                 #if defined(AUDIO_OUT_MONO)
 106                 /* Load the sample into the PWM timer channel */
 107                 OCR3A = (MixedSample_8Bit ^ (1 << 7));
 108                 #elif defined(AUDIO_OUT_STEREO)
 109                 /* Load the dual 8-bit samples into the PWM timer channels */
 110                 OCR3A = (LeftSample_8Bit  ^ (1 << 7));
 111                 OCR3B = (RightSample_8Bit ^ (1 << 7));
 112                 #elif defined(AUDIO_OUT_PORTC)
 113                 /* Load the 8-bit mixed sample into PORTC */
 114                 PORTC = MixedSample_8Bit;
 115                 #endif
 116
 117                 uint8_t LEDMask = LEDS_NO_LEDS;
 118
 119                 /* Turn on LEDs as the sample amplitude increases */
 120                 if (MixedSample_8Bit > 16)
 121                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3 | LEDS_LED4);
 122                 else if (MixedSample_8Bit > 8)
 123                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3);
 124                 else if (MixedSample_8Bit > 4)
 125                   LEDMask = (LEDS_LED1 | LEDS_LED2);
 126                 else if (MixedSample_8Bit > 2)
 127                   LEDMask = (LEDS_LED1);
 128
 129                 LEDs_SetAllLEDs(LEDMask);
 130         }
 131
 132         Endpoint_SelectEndpoint(PrevEndpoint);
 133 }
 134
 135 /** Event handler for the library USB Connection event. */
 136 void EVENT_USB_Device_Connect(void)
 137 {
 138         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 139
 140         /* Sample reload timer initialization */
 141         TIMSK0  = (1 << OCIE0A);
 142         OCR0A   = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);
 143         TCCR0A  = (1 << WGM01);  // CTC mode
 144         TCCR0B  = (1 << CS01);   // Fcpu/8 speed
 145
 146         #if defined(AUDIO_OUT_MONO)
 147         /* Set speaker as output */
 148         DDRC   |= (1 << 6);
 149         #elif defined(AUDIO_OUT_STEREO)
 150         /* Set speakers as outputs */
 151         DDRC   |= ((1 << 6) | (1 << 5));
 152         #elif defined(AUDIO_OUT_PORTC)
 153         /* Set PORTC as outputs */
 154         DDRC   |= 0xFF;
 155         #endif
 156
 157         #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 158         /* PWM speaker timer initialization */
 159         TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
 160                 | (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
 161         TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, F_CPU speed
 162         #endif
 163 }
 164
 165 /** Event handler for the library USB Disconnection event. */
 166 void EVENT_USB_Device_Disconnect(void)
 167 {
 168         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 169
 170         /* Stop the sample reload timer */
 171         TCCR0B = 0;
 172
 173         #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 174         /* Stop the PWM generation timer */
 175         TCCR3B = 0;
 176         #endif
 177
 178         #if defined(AUDIO_OUT_MONO)
 179         /* Set speaker as input to reduce current draw */
 180         DDRC  &= ~(1 << 6);
 181         #elif defined(AUDIO_OUT_STEREO)
 182         /* Set speakers as inputs to reduce current draw */
 183         DDRC  &= ~((1 << 6) | (1 << 5));
 184         #elif defined(AUDIO_OUT_PORTC)
 185         /* Set PORTC low */
 186         PORTC = 0x00;
 187         #endif
 188 }
 189
 190 /** Event handler for the library USB Configuration Changed event. */
 191 void EVENT_USB_Device_ConfigurationChanged(void)
 192 {
 193         bool ConfigSuccess = true;
 194
 195         ConfigSuccess &= Audio_Device_ConfigureEndpoints(&Speaker_Audio_Interface);
 196
 197         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 198 }
 199
 200 /** Event handler for the library USB Control Request reception event. */
 201 void EVENT_USB_Device_ControlRequest(void)
 202 {
 203         Audio_Device_ProcessControlRequest(&Speaker_Audio_Interface);
 204 }
 205
 206 /** Audio class driver callback for the setting and retrieval of streaming endpoint properties. This callback must be implemented
 207  *  in the user application to handle property manipulations on streaming audio endpoints.
 208  *
 209  *  When the DataLength parameter is NULL, this callback should only indicate whether the specified operation is valid for
 210  *  the given endpoint index, and should return as fast as possible. When non-NULL, this value may be altered for GET operations
 211  *  to indicate the size of the retreived data.
 212  *
 213  *  \note The length of the retrieved data stored into the Data buffer on GET operations should not exceed the initial value
 214  *        of the \c DataLength parameter.
 215  *
 216  *  \param[in,out] AudioInterfaceInfo  Pointer to a structure containing an Audio Class configuration and state.
 217  *  \param[in]     EndpointProperty    Property of the endpoint to get or set, a value from Audio_ClassRequests_t.
 218  *  \param[in]     EndpointAddress     Address of the streaming endpoint whose property is being referenced.
 219  *  \param[in]     EndpointControl     Parameter of the endpoint to get or set, a value from Audio_EndpointControls_t.
 220  *  \param[in,out] DataLength          For SET operations, the length of the parameter data to set. For GET operations, the maximum
 221  *                                     length of the retrieved data. When NULL, the function should return whether the given property
 222  *                                     and parameter is valid for the requested endpoint without reading or modifying the Data buffer.
 223  *  \param[in,out] Data                Pointer to a location where the parameter data is stored for SET operations, or where
 224  *                                     the retrieved data is to be stored for GET operations.
 225  *
 226  *  \return Boolean true if the property get/set was successful, false otherwise
 227  */
 228 bool CALLBACK_Audio_Device_GetSetEndpointProperty(USB_ClassInfo_Audio_Device_t* const AudioInterfaceInfo,
 229                                                   const uint8_t EndpointProperty,
 230                                                   const uint8_t EndpointAddress,
 231                                                   const uint8_t EndpointControl,
 232                                                   uint16_t* const DataLength,
 233                                                   uint8_t* Data)
 234 {
 235         /* Check the requested endpoint to see if a supported endpoint is being manipulated */
 236         if (EndpointAddress == (ENDPOINT_DIR_OUT | Speaker_Audio_Interface.Config.DataOUTEndpointNumber))
 237         {
 238                 /* Check the requested control to see if a supported control is being manipulated */
 239                 if (EndpointControl == AUDIO_EPCONTROL_SamplingFreq)
 240                 {
 241                         switch (EndpointProperty)
 242                         {
 243                                 case AUDIO_REQ_SetCurrent:
 244                                         /* Check if we are just testing for a valid property, or actually adjusting it */
 245                                         if (DataLength != NULL)
 246                                         {
 247                                                 /* Set the new sampling frequency to the value given by the host */
 248                                                 CurrentAudioSampleFrequency = (((uint32_t)Data[2] << 16) | ((uint32_t)Data[1] << 8) | (uint32_t)Data[0]);
 249
 250                                                 /* Adjust sample reload timer to the new frequency */
 251                                                 OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);
 252                                         }
 253
 254                                         return true;
 255                                 case AUDIO_REQ_GetCurrent:
 256                                         /* Check if we are just testing for a valid property, or actually reading it */
 257                                         if (DataLength != NULL)
 258                                         {
 259                                                 *DataLength = 3;
 260
 261                                                 Data[2] = (CurrentAudioSampleFrequency >> 16);
 262                                                 Data[1] = (CurrentAudioSampleFrequency >> 8);
 263                                                 Data[0] = (CurrentAudioSampleFrequency &  0xFF);
 264                                         }
 265
 266                                         return true;
 267                         }
 268                 }
 269         }
 270
 271         return false;
 272 }
 273