text: /*
               LUFA Library
       Copyright (C) Dean Camera, 2011.
  
    dean [at] fourwalledcubicle [dot] com
             www.lufa-lib.org
  */
  
  /*
    Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  
    Permission to use, copy, modify, distribute, and sell this
    software and its documentation for any purpose is hereby granted
    without fee, provided that the above copyright notice appear in
    all copies and that both that the copyright notice and this
    permission notice and warranty disclaimer appear in supporting
    documentation, and that the name of the author not be used in
    advertising or publicity pertaining to distribution of the
    software without specific, written prior permission.
  
    The author disclaim all warranties with regard to this
    software, including all implied warranties of merchantability
    and fitness.  In no event shall the author be liable for any
    special, indirect or consequential damages or any damages
    whatsoever resulting from loss of use, data or profits, whether
    in an action of contract, negligence or other tortious action,
    arising out of or in connection with the use or performance of
    this software.
  */
  
  /** \file
   *
   *  Main source file for the AudioOutputHost demo. This file contains the main tasks of
   *  the demo and is responsible for the initial application hardware configuration.
   */
  
  #include "AudioOutputHost.h"
  
  /** LUFA Audio Class driver interface configuration and state information. This structure is
   *  passed to all Audio Class driver functions, so that multiple instances of the same class
   *  within a device can be differentiated from one another.
   */
  USB_ClassInfo_Audio_Host_t Speaker_Audio_Interface =
  	{
  		.Config =
  			{
  				.DataOUTPipeNumber = 1,
  			},
  	};
  
  
  /** Main program entry point. This routine configures the hardware required by the application, then
   *  enters a loop to run the application tasks in sequence.
   */
  int main(void)
  {
  	SetupHardware();
  
  	puts_P(PSTR(ESC_FG_CYAN "Audio Output Host Demo running.\r\n" ESC_FG_WHITE));
  
  	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  	sei();
  
  	for (;;)
  	{
  		Audio_Host_USBTask(&Speaker_Audio_Interface);
  		USB_USBTask();
  	}
  }
  
  /** ISR to handle the reloading of the PWM timer with the next sample. */
  ISR(TIMER0_COMPA_vect, ISR_BLOCK)
  {
  	uint8_t PrevPipe = Pipe_GetCurrentPipe();
  
  	/* Check that the USB bus is ready for the next sample to write */
  	if (Audio_Host_IsReadyForNextSample(&Speaker_Audio_Interface))
  	{
  		int16_t AudioSample;
  
  		#if defined(USE_TEST_TONE)
  			static uint8_t SquareWaveSampleCount;
  			static int16_t CurrentWaveValue;
  			
  			/* In test tone mode, generate a square wave at 1/256 of the sample rate */
  			if (SquareWaveSampleCount++ == 0xFF)
  			  CurrentWaveValue ^= 0x8000;
  			
  			/* Only generate audio if the board button is being pressed */
  			AudioSample = (Buttons_GetStatus() & BUTTONS_BUTTON1) ? CurrentWaveValue : 0;
  		#else
  			/* Audio sample is ADC value scaled to fit the entire range */
  			AudioSample = ((SAMPLE_MAX_RANGE / ADC_MAX_RANGE) * ADC_GetResult());
  
  			#if defined(MICROPHONE_BIASED_TO_HALF_RAIL)
  			/* Microphone is biased to half rail voltage, subtract the bias from the sample value */
  			AudioSample -= (SAMPLE_MAX_RANGE / 2);
  			#endif
  		#endif
  		
  		Audio_Host_WriteSample16(&Speaker_Audio_Interface, AudioSample);	
  		Audio_Host_WriteSample16(&Speaker_Audio_Interface, AudioSample);
  	}
  	
  	Pipe_SelectPipe(PrevPipe);
  }
  
  /** Configures the board hardware and chip peripherals for the demo's functionality. */
  void SetupHardware(void)
  {
  	/* Disable watchdog if enabled by bootloader/fuses */
  	MCUSR &= ~(1 << WDRF);
  	wdt_disable();
  
  	/* Disable clock division */
  	clock_prescale_set(clock_div_1);
  
  	/* Hardware Initialization */
  	Serial_Init(9600, false);
  	LEDs_Init();
  	Buttons_Init();
  	ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32);
  	ADC_SetupChannel(MIC_IN_ADC_CHANNEL);
  	USB_Init();
  
  	/* Create a stdio stream for the serial port for stdin and stdout */
  	Serial_CreateStream(NULL);
  }
  
  /** Event handler for the USB_DeviceAttached event. This indicates that a device has been attached to the host, and
   *  starts the library USB task to begin the enumeration and USB management process.
   */
  void EVENT_USB_Host_DeviceAttached(void)
  {
  	puts_P(PSTR("Device Attached.\r\n"));
  	LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
  }
  
  /** Event handler for the USB_DeviceUnattached event. This indicates that a device has been removed from the host, and
   *  stops the library USB task management process.
   */
  void EVENT_USB_Host_DeviceUnattached(void)
  {
  	puts_P(PSTR("\r\nDevice Unattached.\r\n"));
  	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  }
  
  /** Event handler for the USB_DeviceEnumerationComplete event. This indicates that a device has been successfully
   *  enumerated by the host and is now ready to be used by the application.
   */
  void EVENT_USB_Host_DeviceEnumerationComplete(void)
  {
  	LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
  
  	uint16_t ConfigDescriptorSize;
  	uint8_t  ConfigDescriptorData[512];
  
  	if (USB_Host_GetDeviceConfigDescriptor(1, &ConfigDescriptorSize, ConfigDescriptorData,
  	                                       sizeof(ConfigDescriptorData)) != HOST_GETCONFIG_Successful)
  	{
  		puts_P(PSTR("Error Retrieving Configuration Descriptor.\r\n"));
  		LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
  		return;
  	}
  
  	if (Audio_Host_ConfigurePipes(&Speaker_Audio_Interface,
  	                              ConfigDescriptorSize, ConfigDescriptorData) != AUDIO_ENUMERROR_NoError)
  	{
  		puts_P(PSTR("Attached Device Not a Valid Audio Output Device.\r\n"));
  		LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
  		return;
  	}
  
  	if (USB_Host_SetDeviceConfiguration(1) != HOST_SENDCONTROL_Successful)
  	{
  		puts_P(PSTR("Error Setting Device Configuration.\r\n"));
  		LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
  		return;
  	}
  
  	if (Audio_Host_StartStopStreaming(&Speaker_Audio_Interface, true) != HOST_SENDCONTROL_Successful)
  	{
  		puts_P(PSTR("Error Enabling Audio Stream.\r\n"));
  		LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
  		USB_Host_SetDeviceConfiguration(0);
  		return;
  	}
  	
  	USB_Audio_SampleFreq_t SampleRate = AUDIO_SAMPLE_FREQ(48000);
  	if (Audio_Host_GetSetEndpointProperty(&Speaker_Audio_Interface, Speaker_Audio_Interface.Config.DataOUTPipeNumber,
  	                                      AUDIO_REQ_SetCurrent, AUDIO_EPCONTROL_SamplingFreq,
  	                                      sizeof(SampleRate), &SampleRate) != HOST_SENDCONTROL_Successful)
  	{
  		puts_P(PSTR("Error Setting Audio Sampling Frequency.\r\n"));
  		LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
  		USB_Host_SetDeviceConfiguration(0);
  		return;
  	}
  
  	/* Sample reload timer initialization */
  	TIMSK0  = (1 << OCIE0A);
  	OCR0A   = ((F_CPU / 8 / 48000) - 1);
  	TCCR0A  = (1 << WGM01);  // CTC mode
  	TCCR0B  = (1 << CS01);   // Fcpu/8 speed
  
  	puts_P(PSTR("Audio Device Enumerated.\r\n"));
  	LEDs_SetAllLEDs(LEDMASK_USB_READY);
  }
  
  /** Event handler for the USB_HostError event. This indicates that a hardware error occurred while in host mode. */
  void EVENT_USB_Host_HostError(const uint8_t ErrorCode)
  {
  	USB_Disable();
  
  	printf_P(PSTR(ESC_FG_RED "Host Mode Error\r\n"
  	                         " -- Error Code %d\r\n" ESC_FG_WHITE), ErrorCode);
  
  	LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
  	for(;;);
  }
  
  /** Event handler for the USB_DeviceEnumerationFailed event. This indicates that a problem occurred while
   *  enumerating an attached USB device.
   */
  void EVENT_USB_Host_DeviceEnumerationFailed(const uint8_t ErrorCode,
                                              const uint8_t SubErrorCode)
  {
  	printf_P(PSTR(ESC_FG_RED "Dev Enum Error\r\n"
  	                         " -- Error Code %d\r\n"
  	                         " -- Sub Error Code %d\r\n"
  	                         " -- In State %d\r\n" ESC_FG_WHITE), ErrorCode, SubErrorCode, USB_HostState);
  
  	LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
  }
  
  