1 files changed, 293 insertions, 0 deletions
diff --git a/lib/lufa/Demos/Device/LowLevel/AudioOutput/AudioOutput.c b/lib/lufa/Demos/Device/LowLevel/AudioOutput/AudioOutput.c
new file mode 100644
index 000000000..7966ba6ea
--- /dev/null
+++ b/lib/lufa/Demos/Device/LowLevel/AudioOutput/AudioOutput.c
@@ -0,0 +1,293 @@
+/*
+             LUFA Library
+     Copyright (C) Dean Camera, 2017.
+
+  dean [at] fourwalledcubicle [dot] com
+           www.lufa-lib.org
+*/
+
+/*
+  Copyright 2017  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 disclaims 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 AudioOutput demo. This file contains the main tasks of the demo and
+ *  is responsible for the initial application hardware configuration.
+ */
+
+#include "AudioOutput.h"
+
+/** Flag to indicate if the streaming audio alternative interface has been selected by the host. */
+static bool StreamingAudioInterfaceSelected = false;
+
+/** Current audio sampling frequency of the streaming audio endpoint. */
+static uint32_t CurrentAudioSampleFrequency = 48000;
+
+
+/** Main program entry point. This routine contains the overall program flow, including initial
+ *  setup of all components and the main program loop.
+ */
+int main(void)
+{
+	SetupHardware();
+
+	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
+	GlobalInterruptEnable();
+
+	for (;;)
+	{
+		USB_USBTask();
+	}
+}
+
+/** Configures the board hardware and chip peripherals for the demo's functionality. */
+void SetupHardware(void)
+{
+#if (ARCH == ARCH_AVR8)
+	/* Disable watchdog if enabled by bootloader/fuses */
+	MCUSR &= ~(1 << WDRF);
+	wdt_disable();
+
+	/* Disable clock division */
+	clock_prescale_set(clock_div_1);
+#endif
+
+	/* Hardware Initialization */
+	LEDs_Init();
+	USB_Init();
+}
+
+/** Event handler for the USB_Connect event. This indicates that the device is enumerating via the status LEDs, and
+ *  configures the sample update and PWM timers.
+ */
+void EVENT_USB_Device_Connect(void)
+{
+	/* Indicate USB enumerating */
+	LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
+
+	/* Sample reload timer initialization */
+	TIMSK0 = (1 << OCIE0A);
+	OCR0A  = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);
+	TCCR0A = (1 << WGM01);  // CTC mode
+	TCCR0B = (1 << CS01);   // Fcpu/8 speed
+
+	#if defined(AUDIO_OUT_MONO)
+	/* Set speaker as output */
+	DDRC  |= (1 << 6);
+	#elif defined(AUDIO_OUT_STEREO)
+	/* Set speakers as outputs */
+	DDRC  |= ((1 << 6) | (1 << 5));
+	#elif defined(AUDIO_OUT_PORTC)
+	/* Set PORTC as outputs */
+	DDRC  |= 0xFF;
+	#endif
+
+	#if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
+	/* PWM speaker timer initialization */
+	TCCR3A = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)
+	                       | (1 << COM3B1) | (1 << COM3B0)); // Set on match, clear on TOP
+	TCCR3B = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, F_CPU speed
+	#endif
+}
+
+/** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via
+ *  the status LEDs, disables the sample update and PWM output timers and stops the USB and Audio management tasks.
+ */
+void EVENT_USB_Device_Disconnect(void)
+{
+	/* Stop the timers */
+	TCCR0B = 0;
+	#if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO))
+	TCCR3B = 0;
+	#endif
+
+	#if defined(AUDIO_OUT_MONO)
+	/* Set speaker as input to reduce current draw */
+	DDRC  &= ~(1 << 6);
+	#elif defined(AUDIO_OUT_STEREO)
+	/* Set speakers as inputs to reduce current draw */
+	DDRC  &= ~((1 << 6) | (1 << 5));
+	#elif defined(AUDIO_OUT_PORTC)
+	/* Set PORTC low */
+	PORTC = 0x00;
+	#endif
+
+	/* Indicate streaming audio interface not selected */
+	StreamingAudioInterfaceSelected = false;
+
+	/* Indicate USB not ready */
+	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
+}
+
+/** Event handler for the USB_ConfigurationChanged event. This is fired when the host set the current configuration
+ *  of the USB device after enumeration - the device endpoints are configured.
+ */
+void EVENT_USB_Device_ConfigurationChanged(void)
+{
+	bool ConfigSuccess = true;
+
+	/* Setup Audio Stream Endpoint */
+	ConfigSuccess &= Endpoint_ConfigureEndpoint(AUDIO_STREAM_EPADDR, EP_TYPE_ISOCHRONOUS, AUDIO_STREAM_EPSIZE, 2);
+
+	/* Indicate endpoint configuration success or failure */
+	LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
+}
+
+/** Event handler for the USB_ControlRequest event. This is used to catch and process control requests sent to
+ *  the device from the USB host before passing along unhandled control requests to the library for processing
+ *  internally.
+ */
+void EVENT_USB_Device_ControlRequest(void)
+{
+	/* Process General and Audio specific control requests */
+	switch (USB_ControlRequest.bRequest)
+	{
+		case REQ_SetInterface:
+			/* Set Interface is not handled by the library, as its function is application-specific */
+			if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_STANDARD | REQREC_INTERFACE))
+			{
+				Endpoint_ClearSETUP();
+				Endpoint_ClearStatusStage();
+
+				/* Check if the host is enabling the audio interface (setting AlternateSetting to 1) */
+				StreamingAudioInterfaceSelected = ((USB_ControlRequest.wValue) != 0);
+			}
+
+			break;
+		case AUDIO_REQ_GetStatus:
+			/* Get Status request can be directed at either the interface or endpoint, neither is currently used
+			 * according to the latest USB Audio 1.0 standard, but must be ACKed with no data when requested */
+			if ((USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE)) ||
+			    (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_ENDPOINT)))
+			{
+				Endpoint_ClearSETUP();
+				Endpoint_ClearStatusStage();
+			}
+
+			break;
+		case AUDIO_REQ_SetCurrent:
+			if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_ENDPOINT))
+			{
+				/* Extract out the relevant request information to get the target Endpoint address and control being set */
+				uint8_t EndpointAddress = (uint8_t)USB_ControlRequest.wIndex;
+				uint8_t EndpointControl = (USB_ControlRequest.wValue >> 8);
+
+				/* Only handle SET CURRENT requests to the audio endpoint's sample frequency property */
+				if ((EndpointAddress == AUDIO_STREAM_EPADDR) && (EndpointControl == AUDIO_EPCONTROL_SamplingFreq))
+				{
+					uint8_t SampleRate[3];
+
+					Endpoint_ClearSETUP();
+					Endpoint_Read_Control_Stream_LE(SampleRate, sizeof(SampleRate));
+					Endpoint_ClearIN();
+
+					/* Set the new sampling frequency to the value given by the host */
+					CurrentAudioSampleFrequency = (((uint32_t)SampleRate[2] << 16) | ((uint32_t)SampleRate[1] << 8) | (uint32_t)SampleRate[0]);
+
+					/* Adjust sample reload timer to the new frequency */
+					OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);
+				}
+			}
+
+			break;
+		case AUDIO_REQ_GetCurrent:
+			if (USB_ControlRequest.bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_ENDPOINT))
+			{
+				/* Extract out the relevant request information to get the target Endpoint address and control being retrieved */
+				uint8_t EndpointAddress = (uint8_t)USB_ControlRequest.wIndex;
+				uint8_t EndpointControl = (USB_ControlRequest.wValue >> 8);
+
+				/* Only handle GET CURRENT requests to the audio endpoint's sample frequency property */
+				if ((EndpointAddress == AUDIO_STREAM_EPADDR) && (EndpointControl == AUDIO_EPCONTROL_SamplingFreq))
+				{
+					uint8_t SampleRate[3];
+
+					/* Convert the sampling rate value into the 24-bit format the host expects for the property */
+					SampleRate[2] = (CurrentAudioSampleFrequency >> 16);
+					SampleRate[1] = (CurrentAudioSampleFrequency >> 8);
+					SampleRate[0] = (CurrentAudioSampleFrequency &  0xFF);
+
+					Endpoint_ClearSETUP();
+					Endpoint_Write_Control_Stream_LE(SampleRate, sizeof(SampleRate));
+					Endpoint_ClearOUT();
+				}
+			}
+
+			break;
+	}
+}
+
+/** ISR to handle the reloading of the PWM timer with the next sample. */
+ISR(TIMER0_COMPA_vect, ISR_BLOCK)
+{
+	uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint();
+
+	/* Select the audio stream endpoint */
+	Endpoint_SelectEndpoint(AUDIO_STREAM_EPADDR);
+
+	/* Check if the current endpoint can be read from (contains a packet) and the host is sending data */
+	if (Endpoint_IsOUTReceived() && StreamingAudioInterfaceSelected)
+	{
+		/* Retrieve the signed 16-bit left and right audio samples, convert to 8-bit */
+		int8_t LeftSample_8Bit   = ((int16_t)Endpoint_Read_16_LE() >> 8);
+		int8_t RightSample_8Bit  = ((int16_t)Endpoint_Read_16_LE() >> 8);
+
+		/* Mix the two channels together to produce a mono, 8-bit sample */
+		int8_t MixedSample_8Bit  = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1);
+
+		/* Check to see if the bank is now empty */
+		if (!(Endpoint_IsReadWriteAllowed()))
+		{
+			/* Acknowledge the packet, clear the bank ready for the next packet */
+			Endpoint_ClearOUT();
+		}
+
+		#if defined(AUDIO_OUT_MONO)
+		/* Load the sample into the PWM timer channel */
+		OCR3A = (MixedSample_8Bit ^ (1 << 7));
+		#elif defined(AUDIO_OUT_STEREO)
+		/* Load the dual 8-bit samples into the PWM timer channels */
+		OCR3A = (LeftSample_8Bit  ^ (1 << 7));
+		OCR3B = (RightSample_8Bit ^ (1 << 7));
+		#elif defined(AUDIO_OUT_PORTC)
+		/* Load the 8-bit mixed sample into PORTC */
+		PORTC = MixedSample_8Bit;
+		#endif
+
+		uint8_t LEDMask = LEDS_NO_LEDS;
+
+		/* Turn on LEDs as the sample amplitude increases */
+		if (MixedSample_8Bit > 16)
+		  LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3 | LEDS_LED4);
+		else if (MixedSample_8Bit > 8)
+		  LEDMask = (LEDS_LED1 | LEDS_LED2 | LEDS_LED3);
+		else if (MixedSample_8Bit > 4)
+		  LEDMask = (LEDS_LED1 | LEDS_LED2);
+		else if (MixedSample_8Bit > 2)
+		  LEDMask = (LEDS_LED1);
+
+		LEDs_SetAllLEDs(LEDMask);
+	}
+
+	Endpoint_SelectEndpoint(PrevEndpoint);
+}
+