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257 lines
8.4 KiB
257 lines
8.4 KiB
/*
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LUFA Library
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Copyright (C) Dean Camera, 2009.
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dean [at] fourwalledcubicle [dot] com
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www.fourwalledcubicle.com
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*/
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/*
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Copyright 2009 Dean Camera (dean [at] fourwalledcubicle [dot] com)
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Permission to use, copy, modify, and distribute this software
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and its documentation for any purpose and without fee is hereby
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granted, provided that the above copyright notice appear in all
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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 Output 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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bool StreamingAudioInterfaceSelected = false;
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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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for (;;)
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{
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USB_Audio_Task();
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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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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_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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OCR0A = (F_CPU / AUDIO_SAMPLE_FREQUENCY) - 1;
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TCCR0A = (1 << WGM01); // CTC mode
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TCCR0B = (1 << CS00); // Fcpu 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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TCCRxA = ((1 << WGMx0) | (1 << COMxA1) | (1 << COMxA0)
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| (1 << COMxB1) | (1 << COMxB0)); // Set on match, clear on TOP
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TCCRxB = ((1 << WGMx2) | (1 << CSx0)); // Fast 8-Bit PWM, Fcpu 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_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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TCCRxB = 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_ConfigurationChanged(void)
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{
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/* Indicate USB connected and ready */
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LEDs_SetAllLEDs(LEDMASK_USB_READY);
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/* Setup audio stream endpoint */
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if (!(Endpoint_ConfigureEndpoint(AUDIO_STREAM_EPNUM, EP_TYPE_ISOCHRONOUS,
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ENDPOINT_DIR_OUT, AUDIO_STREAM_EPSIZE,
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ENDPOINT_BANK_DOUBLE)))
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{
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LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
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}
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}
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/** Event handler for the USB_UnhandledControlPacket event. This is used to catch standard and class specific
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* control requests that are not handled internally by the USB library (including the Audio class-specific
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* requests) so that they can be handled appropriately for the application.
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*/
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void EVENT_USB_UnhandledControlPacket(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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/* 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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/* Acknowledge status stage */
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while (!(Endpoint_IsINReady()));
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Endpoint_ClearIN();
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}
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break;
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}
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}
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/** Task to manage the Audio interface, reading in audio samples from the host, and outputting them to the speakers/LEDs as
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* desired.
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*/
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void USB_Audio_Task(void)
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{
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/* Check to see if the streaming interface is selected, if not the host is not receiving audio */
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if (!(StreamingAudioInterfaceSelected))
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return;
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/* Select the audio stream endpoint */
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Endpoint_SelectEndpoint(AUDIO_STREAM_EPNUM);
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/* Check if the current endpoint can be read from (contains a packet) and that the next sample should be read */
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if (Endpoint_IsOUTReceived() && (TIFR0 & (1 << OCF0A)))
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{
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/* Clear the sample reload timer */
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TIFR0 |= (1 << OCF0A);
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/* Retrieve the signed 16-bit left and right audio samples */
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int16_t LeftSample_16Bit = (int16_t)Endpoint_Read_Word_LE();
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int16_t RightSample_16Bit = (int16_t)Endpoint_Read_Word_LE();
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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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/* Massage signed 16-bit left and right audio samples into signed 8-bit */
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int8_t LeftSample_8Bit = (LeftSample_16Bit >> 8);
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int8_t RightSample_8Bit = (RightSample_16Bit >> 8);
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#if defined(AUDIO_OUT_MONO)
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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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/* Load the sample into the PWM timer channel */
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OCRxA = ((uint8_t)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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OCRxA = ((uint8_t)LeftSample_8Bit ^ (1 << 7));
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OCRxB = ((uint8_t)RightSample_8Bit ^ (1 << 7));
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#elif defined(AUDIO_OUT_PORTC)
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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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PORTC = MixedSample_8Bit;
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#else
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uint8_t LEDMask = LEDS_NO_LEDS;
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/* Make left channel positive (absolute) */
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if (LeftSample_8Bit < 0)
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LeftSample_8Bit = -LeftSample_8Bit;
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/* Make right channel positive (absolute) */
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if (RightSample_8Bit < 0)
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RightSample_8Bit = -RightSample_8Bit;
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/* Set first LED based on sample value */
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if (LeftSample_8Bit < ((128 / 8) * 1))
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LEDMask |= LEDS_LED2;
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else if (LeftSample_8Bit < ((128 / 8) * 3))
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LEDMask |= (LEDS_LED1 | LEDS_LED2);
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else
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LEDMask |= LEDS_LED1;
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/* Set second LED based on sample value */
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if (RightSample_8Bit < ((128 / 8) * 1))
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LEDMask |= LEDS_LED4;
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else if (RightSample_8Bit < ((128 / 8) * 3))
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LEDMask |= (LEDS_LED3 | LEDS_LED4);
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else
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LEDMask |= LEDS_LED3;
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LEDs_SetAllLEDs(LEDMask);
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#endif
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}
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}
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