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
  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(&Speaker_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         USB_Init();
  85 }
  86
  87 /** ISR to handle the reloading of the PWM timer with the next sample. */
  88 ISR(TIMER0_COMPA_vect, ISR_BLOCK)
  89 {
  90         uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint();
  91
  92         if (Audio_Device_IsSampleReceived(&Speaker_Audio_Interface))
  93         {
  94                 /* Retrieve the signed 16-bit left and right audio samples, convert to 8-bit */
  95                 int8_t LeftSample_8Bit  = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
  96                 int8_t RightSample_8Bit = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
  97
  98                 /* Mix the two channels together to produce a mono, 8-bit sample */
  99                 int8_t MixedSample_8Bit = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
 100
 101                 #if defined(AUDIO_OUT_MONO)
 102                 /* Load the sample into the PWM timer channel */
 103                 OCR3A = (MixedSample_8Bit ^ (1 << 7));
 104                 #elif defined(AUDIO_OUT_STEREO)
 105                 /* Load the dual 8-bit samples into the PWM timer channels */
 106                 OCR3A = (LeftSample_8Bit  ^ (1 << 7));
 107                 OCR3B = (RightSample_8Bit ^ (1 << 7));
 108                 #elif defined(AUDIO_OUT_PORTC)
 109                 /* Load the 8-bit mixed sample into PORTC */
 110                 PORTC = MixedSample_8Bit;
 111                 #endif
 112
 113                 uint8_t LEDMask = LEDS_NO_LEDS;
 114
 115                 /* Turn on LEDs as the sample amplitude increases */
 116                 if (MixedSample_8Bit > 16)
 117                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3 | LEDS_LED4);
 118                 else if (MixedSample_8Bit > 8)
 119                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3);
 120                 else if (MixedSample_8Bit > 4)
 121                   LEDMask = (LEDS_LED1 | LEDS_LED2);
 122                 else if (MixedSample_8Bit > 2)
 123                   LEDMask = (LEDS_LED1);
 124
 125                 LEDs_SetAllLEDs(LEDMask);
 126         }
 127
 128         Endpoint_SelectEndpoint(PrevEndpoint);
 129 }
 130
 131 /** Event handler for the library USB Connection event. */
 132 void EVENT_USB_Device_Connect(void)
 133 {
 134         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 135
 136         /* Sample reload timer initialization */
 137         TIMSK0  = (1 << OCIE0A);
 138         OCR0A   = ((F_CPU / 8 / AUDIO_SAMPLE_FREQUENCY) - 1);
 139         TCCR0A  = (1 << WGM01);  // CTC mode
 140         TCCR0B  = (1 << CS01);   // Fcpu/8 speed
 141
 142         #if defined(AUDIO_OUT_MONO)
 143         /* Set speaker as output */
 144         DDRC   |= (1 << 6);
 145         #elif defined(AUDIO_OUT_STEREO)
 146         /* Set speakers as outputs */
 147         DDRC   |= ((1 << 6) | (1 << 5));
 148         #elif defined(AUDIO_OUT_PORTC)
 149         /* Set PORTC as outputs */
 150         DDRC   |= 0xFF;
 151         #endif
 152
 153         #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 154         /* PWM speaker timer initialization */
 155         TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
 156                 | (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
 157         TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, F_CPU speed
 158         #endif
 159 }
 160
 161 /** Event handler for the library USB Disconnection event. */
 162 void EVENT_USB_Device_Disconnect(void)
 163 {
 164         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 165
 166         /* Stop the sample reload timer */
 167         TCCR0B = 0;
 168
 169         #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 170         /* Stop the PWM generation timer */
 171         TCCR3B = 0;
 172         #endif
 173
 174         #if defined(AUDIO_OUT_MONO)
 175         /* Set speaker as input to reduce current draw */
 176         DDRC  &= ~(1 << 6);
 177         #elif defined(AUDIO_OUT_STEREO)
 178         /* Set speakers as inputs to reduce current draw */
 179         DDRC  &= ~((1 << 6) | (1 << 5));
 180         #elif defined(AUDIO_OUT_PORTC)
 181         /* Set PORTC low */
 182         PORTC = 0x00;
 183         #endif
 184 }
 185
 186 /** Event handler for the library USB Configuration Changed event. */
 187 void EVENT_USB_Device_ConfigurationChanged(void)
 188 {
 189         bool ConfigSuccess = true;
 190
 191         ConfigSuccess &= Audio_Device_ConfigureEndpoints(&Speaker_Audio_Interface);
 192
 193         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 194 }
 195
 196 /** Event handler for the library USB Control Request reception event. */
 197 void EVENT_USB_Device_ControlRequest(void)
 198 {
 199         Audio_Device_ProcessControlRequest(&Speaker_Audio_Interface);
 200 }
 201