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258 lines
8.8 KiB
258 lines
8.8 KiB
/*
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LUFA Library
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Copyright (C) Dean Camera, 2012.
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dean [at] fourwalledcubicle [dot] com
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www.lufa-lib.org
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*/
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/*
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Copyright 2012 Dean Camera (dean [at] fourwalledcubicle [dot] com)
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Permission to use, copy, modify, distribute, and sell this
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software and its documentation for any purpose is hereby granted
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without fee, provided that the above copyright notice appear in
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all copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the name of the author not be used in
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advertising or publicity pertaining to distribution of the
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software without specific, written prior permission.
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The author disclaim all warranties with regard to this
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software, including all implied warranties of merchantability
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and fitness. In no event shall the author be liable for any
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special, indirect or consequential damages or any damages
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whatsoever resulting from loss of use, data or profits, whether
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in an action of contract, negligence or other tortious action,
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arising out of or in connection with the use or performance of
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this software.
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*/
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/** \file
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*
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* Main source file for the Audio Input demo. This file contains the main tasks of the demo and
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* is responsible for the initial application hardware configuration.
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*/
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#include "AudioInput.h"
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/** Flag to indicate if the streaming audio alternative interface has been selected by the host. */
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static bool StreamingAudioInterfaceSelected = false;
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/** Current audio sampling frequency of the streaming audio endpoint. */
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static uint32_t CurrentAudioSampleFrequency = 48000;
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/** Main program entry point. This routine contains the overall program flow, including initial
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* setup of all components and the main program loop.
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*/
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int main(void)
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{
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SetupHardware();
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LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
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sei();
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for (;;)
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{
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USB_USBTask();
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}
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}
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/** Configures the board hardware and chip peripherals for the demo's functionality. */
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void SetupHardware(void)
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{
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/* Disable watchdog if enabled by bootloader/fuses */
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MCUSR &= ~(1 << WDRF);
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wdt_disable();
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/* Disable clock division */
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clock_prescale_set(clock_div_1);
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/* Hardware Initialization */
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LEDs_Init();
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Buttons_Init();
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ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32);
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ADC_SetupChannel(MIC_IN_ADC_CHANNEL);
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USB_Init();
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/* Start the ADC conversion in free running mode */
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ADC_StartReading(ADC_REFERENCE_AVCC | ADC_RIGHT_ADJUSTED | MIC_IN_ADC_MUX_MASK);
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}
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/** Event handler for the USB_Connect event. This indicates that the device is enumerating via the status LEDs, and
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* configures the sample update and PWM timers.
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*/
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void EVENT_USB_Device_Connect(void)
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{
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/* Indicate USB enumerating */
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LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
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/* Sample reload timer initialization */
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TIMSK0 = (1 << OCIE0A);
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OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);
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TCCR0A = (1 << WGM01); // CTC mode
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TCCR0B = (1 << CS01); // Fcpu/8 speed
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}
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/** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via
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* the status LEDs, disables the sample update and PWM output timers and stops the USB and Audio management tasks.
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*/
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void EVENT_USB_Device_Disconnect(void)
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{
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/* Stop the sample reload timer */
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TCCR0B = 0;
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/* Indicate streaming audio interface not selected */
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StreamingAudioInterfaceSelected = false;
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/* Indicate USB not ready */
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LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
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}
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/** Event handler for the USB_ConfigurationChanged event. This is fired when the host set the current configuration
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* of the USB device after enumeration - the device endpoints are configured.
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*/
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void EVENT_USB_Device_ConfigurationChanged(void)
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{
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bool ConfigSuccess = true;
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/* Setup Audio Stream Endpoint */
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ConfigSuccess &= Endpoint_ConfigureEndpoint(AUDIO_STREAM_EPADDR, EP_TYPE_ISOCHRONOUS, AUDIO_STREAM_EPSIZE, 2);
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/* Indicate endpoint configuration success or failure */
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LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
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}
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/** Event handler for the USB_ControlRequest event. This is used to catch and process control requests sent to
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* the device from the USB host before passing along unhandled control requests to the library for processing
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* internally.
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*/
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void EVENT_USB_Device_ControlRequest(void)
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{
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/* Process General and Audio specific control requests */
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switch (USB_ControlRequest.bRequest)
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{
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case REQ_SetInterface:
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/* Set Interface is not handled by the library, as its function is application-specific */
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if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_STANDARD | REQREC_INTERFACE))
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{
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Endpoint_ClearSETUP();
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Endpoint_ClearStatusStage();
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/* Check if the host is enabling the audio interface (setting AlternateSetting to 1) */
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StreamingAudioInterfaceSelected = ((USB_ControlRequest.wValue) != 0);
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}
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break;
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case AUDIO_REQ_GetStatus:
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/* Get Status request can be directed at either the interface or endpoint, neither is currently used
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* according to the latest USB Audio 1.0 standard, but must be ACKed with no data when requested */
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if ((USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE)) ||
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(USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_ENDPOINT)))
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{
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Endpoint_ClearSETUP();
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Endpoint_ClearStatusStage();
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}
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break;
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case AUDIO_REQ_SetCurrent:
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if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_ENDPOINT))
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{
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/* Extract out the relevant request information to get the target Endpoint address and control being set */
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uint8_t EndpointAddress = (uint8_t)USB_ControlRequest.wIndex;
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uint8_t EndpointControl = (USB_ControlRequest.wValue >> 8);
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/* Only handle SET CURRENT requests to the audio endpoint's sample frequency property */
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if ((EndpointAddress == AUDIO_STREAM_EPADDR) && (EndpointControl == AUDIO_EPCONTROL_SamplingFreq))
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{
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uint8_t SampleRate[3];
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Endpoint_ClearSETUP();
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Endpoint_Read_Control_Stream_LE(SampleRate, sizeof(SampleRate));
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Endpoint_ClearIN();
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/* Set the new sampling frequency to the value given by the host */
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CurrentAudioSampleFrequency = (((uint32_t)SampleRate[2] << 16) | ((uint32_t)SampleRate[1] << 8) | (uint32_t)SampleRate[0]);
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/* Adjust sample reload timer to the new frequency */
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OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);
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}
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}
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break;
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case AUDIO_REQ_GetCurrent:
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if (USB_ControlRequest.bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_ENDPOINT))
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{
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/* Extract out the relevant request information to get the target Endpoint address and control being retrieved */
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uint8_t EndpointAddress = (uint8_t)USB_ControlRequest.wIndex;
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uint8_t EndpointControl = (USB_ControlRequest.wValue >> 8);
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/* Only handle GET CURRENT requests to the audio endpoint's sample frequency property */
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if ((EndpointAddress == AUDIO_STREAM_EPADDR) && (EndpointControl == AUDIO_EPCONTROL_SamplingFreq))
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{
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uint8_t SampleRate[3];
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/* Convert the sampling rate value into the 24-bit format the host expects for the property */
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SampleRate[2] = (CurrentAudioSampleFrequency >> 16);
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SampleRate[1] = (CurrentAudioSampleFrequency >> 8);
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SampleRate[0] = (CurrentAudioSampleFrequency & 0xFF);
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Endpoint_ClearSETUP();
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Endpoint_Write_Control_Stream_LE(SampleRate, sizeof(SampleRate));
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Endpoint_ClearOUT();
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}
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}
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break;
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}
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}
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/** ISR to handle the reloading of the data endpoint with the next sample. */
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ISR(TIMER0_COMPA_vect, ISR_BLOCK)
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{
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uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint();
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/* Select the audio stream endpoint */
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Endpoint_SelectEndpoint(AUDIO_STREAM_EPADDR);
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/* Check if the current endpoint can be written to and that the audio interface is enabled */
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if (Endpoint_IsINReady() && StreamingAudioInterfaceSelected)
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{
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int16_t AudioSample;
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#if defined(USE_TEST_TONE)
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static uint8_t SquareWaveSampleCount;
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static int16_t CurrentWaveValue;
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/* In test tone mode, generate a square wave at 1/256 of the sample rate */
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if (SquareWaveSampleCount++ == 0xFF)
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CurrentWaveValue ^= 0x8000;
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/* Only generate audio if the board button is being pressed */
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AudioSample = (Buttons_GetStatus() & BUTTONS_BUTTON1) ? CurrentWaveValue : 0;
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#else
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/* Audio sample is ADC value scaled to fit the entire range */
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AudioSample = ((SAMPLE_MAX_RANGE / ADC_MAX_RANGE) * ADC_GetResult());
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#if defined(MICROPHONE_BIASED_TO_HALF_RAIL)
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/* Microphone is biased to half rail voltage, subtract the bias from the sample value */
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AudioSample -= (SAMPLE_MAX_RANGE / 2);
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#endif
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#endif
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/* Write the sample to the buffer */
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Endpoint_Write_16_LE(AudioSample);
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/* Check to see if the bank is now full */
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if (!(Endpoint_IsReadWriteAllowed()))
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{
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/* Send the full packet to the host */
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Endpoint_ClearIN();
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}
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}
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Endpoint_SelectEndpoint(PrevEndpoint);
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}
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