294 lines
10 KiB
C
294 lines
10 KiB
C
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/*
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LUFA Library
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Copyright (C) Dean Camera, 2017.
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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 2017 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 disclaims 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 AudioOutput 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 "AudioOutput.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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GlobalInterruptEnable();
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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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#if (ARCH == ARCH_AVR8)
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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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#endif
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/* Hardware Initialization */
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LEDs_Init();
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USB_Init();
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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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#if defined(AUDIO_OUT_MONO)
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/* Set speaker as output */
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DDRC |= (1 << 6);
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#elif defined(AUDIO_OUT_STEREO)
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/* Set speakers as outputs */
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DDRC |= ((1 << 6) | (1 << 5));
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#elif defined(AUDIO_OUT_PORTC)
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/* Set PORTC as outputs */
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DDRC |= 0xFF;
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#endif
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#if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
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/* PWM speaker timer initialization */
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TCCR3A = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
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| (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
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TCCR3B = ((1 << WGM32) | (1 << CS30)); // Fast 8-Bit PWM, F_CPU speed
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#endif
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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 timers */
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TCCR0B = 0;
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#if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
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TCCR3B = 0;
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#endif
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#if defined(AUDIO_OUT_MONO)
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/* Set speaker as input to reduce current draw */
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DDRC &= ~(1 << 6);
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#elif defined(AUDIO_OUT_STEREO)
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/* Set speakers as inputs to reduce current draw */
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DDRC &= ~((1 << 6) | (1 << 5));
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#elif defined(AUDIO_OUT_PORTC)
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/* Set PORTC low */
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PORTC = 0x00;
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#endif
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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 PWM timer 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 read from (contains a packet) and the host is sending data */
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if (Endpoint_IsOUTReceived() && StreamingAudioInterfaceSelected)
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{
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/* Retrieve the signed 16-bit left and right audio samples, convert to 8-bit */
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int8_t LeftSample_8Bit = ((int16_t)Endpoint_Read_16_LE() >> 8);
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int8_t RightSample_8Bit = ((int16_t)Endpoint_Read_16_LE() >> 8);
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/* Mix the two channels together to produce a mono, 8-bit sample */
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int8_t MixedSample_8Bit = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
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/* Check to see if the bank is now empty */
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if (!(Endpoint_IsReadWriteAllowed()))
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{
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/* Acknowledge the packet, clear the bank ready for the next packet */
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Endpoint_ClearOUT();
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}
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#if defined(AUDIO_OUT_MONO)
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/* Load the sample into the PWM timer channel */
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OCR3A = (MixedSample_8Bit ^ (1 << 7));
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#elif defined(AUDIO_OUT_STEREO)
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/* Load the dual 8-bit samples into the PWM timer channels */
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OCR3A = (LeftSample_8Bit ^ (1 << 7));
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OCR3B = (RightSample_8Bit ^ (1 << 7));
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#elif defined(AUDIO_OUT_PORTC)
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/* Load the 8-bit mixed sample into PORTC */
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PORTC = MixedSample_8Bit;
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#endif
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uint8_t LEDMask = LEDS_NO_LEDS;
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/* Turn on LEDs as the sample amplitude increases */
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if (MixedSample_8Bit > 16)
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LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3 | LEDS_LED4);
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else if (MixedSample_8Bit > 8)
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LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3);
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else if (MixedSample_8Bit > 4)
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LEDMask = (LEDS_LED1 | LEDS_LED2);
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else if (MixedSample_8Bit > 2)
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LEDMask = (LEDS_LED1);
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LEDs_SetAllLEDs(LEDMask);
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}
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Endpoint_SelectEndpoint(PrevEndpoint);
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}
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