Demos/Device/ClassDriver/AudioOutput/AudioOutput.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2010  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 /** 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(&Speaker_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         USB_Init();
  84 }
  85
  86 /** ISR to handle the reloading of the PWM timer with the next sample. */
  87 ISR(TIMER0_COMPA_vect, ISR_BLOCK)
  88 {
  89         uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint();
  90
  91         if (Audio_Device_IsSampleReceived(&Speaker_Audio_Interface))
  92         {
  93                 /* Retrieve the signed 16-bit left and right audio samples, convert to 8-bit */
  94                 int8_t LeftSample_8Bit  = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
  95                 int8_t RightSample_8Bit = (Audio_Device_ReadSample16(&Speaker_Audio_Interface) >> 8);
  96
  97                 /* Mix the two channels together to produce a mono, 8-bit sample */
  98                 int8_t MixedSample_8Bit = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
  99
 100                 #if defined(AUDIO_OUT_MONO)
 101                 /* Load the sample into the PWM timer channel */
 102                 OCR3A = (MixedSample_8Bit ^ (1 << 7));
 103                 #elif defined(AUDIO_OUT_STEREO)
 104                 /* Load the dual 8-bit samples into the PWM timer channels */
 105                 OCR3A = (LeftSample_8Bit  ^ (1 << 7));
 106                 OCR3B = (RightSample_8Bit ^ (1 << 7));
 107                 #elif defined(AUDIO_OUT_PORTC)
 108                 /* Load the 8-bit mixed sample into PORTC */
 109                 PORTC = MixedSample_8Bit;
 110                 #endif
 111
 112                 uint8_t LEDMask = LEDS_NO_LEDS;
 113
 114                 /* Turn on LEDs as the sample amplitude increases */
 115                 if (MixedSample_8Bit > 16)
 116                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3 | LEDS_LED4);
 117                 else if (MixedSample_8Bit > 8)
 118                   LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3);
 119                 else if (MixedSample_8Bit > 4)
 120                   LEDMask = (LEDS_LED1 | LEDS_LED2);
 121                 else if (MixedSample_8Bit > 2)
 122                   LEDMask = (LEDS_LED1);
 123
 124                 LEDs_SetAllLEDs(LEDMask);
 125         }
 126
 127         Endpoint_SelectEndpoint(PrevEndpoint);
 128 }
 129
 130 /** Event handler for the library USB Connection event. */
 131 void EVENT_USB_Device_Connect(void)
 132 {
 133         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 134
 135         /* Sample reload timer initialization */
 136         TIMSK0  = (1 << OCIE0A);
 137         OCR0A   = (F_CPU / 8 / AUDIO_SAMPLE_FREQUENCY) - 1;
 138         TCCR0A  = (1 << WGM01);  // CTC mode
 139         TCCR0B  = (1 << CS01);   // Fcpu/8 speed
 140
 141         #if defined(AUDIO_OUT_MONO)
 142         /* Set speaker as output */
 143         DDRC   |= (1 << 6);
 144         #elif defined(AUDIO_OUT_STEREO)
 145         /* Set speakers as outputs */
 146         DDRC   |= ((1 << 6) | (1 << 5));
 147         #elif defined(AUDIO_OUT_PORTC)
 148         /* Set PORTC as outputs */
 149         DDRC   |= 0xFF;
 150         #endif
 151
 152         #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 153         /* PWM speaker timer initialization */
 154         TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
 155                 | (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
 156         TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, F_CPU speed
 157         #endif
 158 }
 159
 160 /** Event handler for the library USB Disconnection event. */
 161 void EVENT_USB_Device_Disconnect(void)
 162 {
 163         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 164
 165         /* Stop the sample reload timer */
 166         TCCR0B = 0;
 167
 168         #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
 169         /* Stop the PWM generation timer */
 170         TCCR3B = 0;
 171         #endif
 172
 173         #if defined(AUDIO_OUT_MONO)
 174         /* Set speaker as input to reduce current draw */
 175         DDRC  &= ~(1 << 6);
 176         #elif defined(AUDIO_OUT_STEREO)
 177         /* Set speakers as inputs to reduce current draw */
 178         DDRC  &= ~((1 << 6) | (1 << 5));
 179         #elif defined(AUDIO_OUT_PORTC)
 180         /* Set PORTC low */
 181         PORTC = 0x00;
 182         #endif
 183 }
 184
 185 /** Event handler for the library USB Configuration Changed event. */
 186 void EVENT_USB_Device_ConfigurationChanged(void)
 187 {
 188         bool ConfigSuccess = true;
 189
 190         ConfigSuccess &= Audio_Device_ConfigureEndpoints(&Speaker_Audio_Interface);
 191
 192         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 193 }
 194
 195 /** Event handler for the library USB Unhandled Control Request event. */
 196 void EVENT_USB_Device_UnhandledControlRequest(void)
 197 {
 198         Audio_Device_ProcessControlRequest(&Speaker_Audio_Interface);
 199 }
 200