qmk_firmware/Projects/Incomplete/MIDIToneGenerator/MIDIToneGenerator.c

/*
             LUFA Library
     Copyright (C) Dean Camera, 2010.
              
  dean [at] fourwalledcubicle [dot] com
      www.fourwalledcubicle.com
*/

/*
  Copyright 2010  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 MIDI demo. This file contains the main tasks of
 *  the demo and is responsible for the initial application hardware configuration.
 */

#include "MIDIToneGenerator.h"

/** LUFA MIDI Class driver interface configuration and state information. This structure is
 *  passed to all MIDI Class driver functions, so that multiple instances of the same class
 *  within a device can be differentiated from one another.
 */
USB_ClassInfo_MIDI_Device_t Keyboard_MIDI_Interface =
	{
		.Config =
			{
				.StreamingInterfaceNumber = 1,

				.DataINEndpointNumber      = MIDI_STREAM_IN_EPNUM,
				.DataINEndpointSize        = MIDI_STREAM_EPSIZE,
				.DataINEndpointDoubleBank  = false,

				.DataOUTEndpointNumber     = MIDI_STREAM_OUT_EPNUM,
				.DataOUTEndpointSize       = MIDI_STREAM_EPSIZE,
				.DataOUTEndpointDoubleBank = false,
			},
	};

const uint8_t SineTable[] PROGMEM =
{
	0x80, 0x83, 0x86, 0x89, 0x8c, 0x8f, 0x92, 0x95, 0x98, 0x9c, 0x9f, 0xa2, 0xa5, 0xa8, 0xab, 0xae, 
	0xb0, 0xb3, 0xb6, 0xb9, 0xbc, 0xbf, 0xc1, 0xc4, 0xc7, 0xc9, 0xcc, 0xce, 0xd1, 0xd3, 0xd5, 0xd8, 
	0xda, 0xdc, 0xde, 0xe0, 0xe2, 0xe4, 0xe6, 0xe8, 0xea, 0xec, 0xed, 0xef, 0xf0, 0xf2, 0xf3, 0xf5, 
	0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfc, 0xfd, 0xfe, 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xfe, 0xfd, 0xfc, 0xfc, 0xfb, 0xfa, 0xf9, 0xf8, 0xf7, 
	0xf6, 0xf5, 0xf3, 0xf2, 0xf0, 0xef, 0xed, 0xec, 0xea, 0xe8, 0xe6, 0xe4, 0xe2, 0xe0, 0xde, 0xdc, 
	0xda, 0xd8, 0xd5, 0xd3, 0xd1, 0xce, 0xcc, 0xc9, 0xc7, 0xc4, 0xc1, 0xbf, 0xbc, 0xb9, 0xb6, 0xb3, 
	0xb0, 0xae, 0xab, 0xa8, 0xa5, 0xa2, 0x9f, 0x9c, 0x98, 0x95, 0x92, 0x8f, 0x8c, 0x89, 0x86, 0x83, 
	0x80, 0x7c, 0x79, 0x76, 0x73, 0x70, 0x6d, 0x6a, 0x67, 0x63, 0x60, 0x5d, 0x5a, 0x57, 0x54, 0x51, 
	0x4f, 0x4c, 0x49, 0x46, 0x43, 0x40, 0x3e, 0x3b, 0x38, 0x36, 0x33, 0x31, 0x2e, 0x2c, 0x2a, 0x27, 
	0x25, 0x23, 0x21, 0x1f, 0x1d, 0x1b, 0x19, 0x17, 0x15, 0x13, 0x12, 0x10, 0x0f, 0x0d, 0x0c, 0x0a, 
	0x09, 0x08, 0x07, 0x06, 0x05, 0x04, 0x03, 0x03, 0x02, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x02, 0x03, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 
	0x09, 0x0a, 0x0c, 0x0d, 0x0f, 0x10, 0x12, 0x13, 0x15, 0x17, 0x19, 0x1b, 0x1d, 0x1f, 0x21, 0x23, 
	0x25, 0x27, 0x2a, 0x2c, 0x2e, 0x31, 0x33, 0x36, 0x38, 0x3b, 0x3e, 0x40, 0x43, 0x46, 0x49, 0x4c, 
	0x4f, 0x51, 0x54, 0x57, 0x5a, 0x5d, 0x60, 0x63, 0x67, 0x6a, 0x6d, 0x70, 0x73, 0x76, 0x79, 0x7c
};

struct
{
	uint8_t Pitch;
	uint8_t Velocity;
	
	uint8_t CurrentPos;
	uint8_t ElapsedTicks;
} ChannelStates[10];

/** 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);
	
	for (;;)
	{
		MIDI_EventPacket_t ReceivedMIDIEvent;
		if (MIDI_Device_ReceiveEventPacket(&Keyboard_MIDI_Interface, &ReceivedMIDIEvent))
		{
			if (ReceivedMIDIEvent.Command == (MIDI_COMMAND_NOTE_ON >> 4))
			{
				ChannelStates[ReceivedMIDIEvent.Data1 & 0x0F].Pitch    = ReceivedMIDIEvent.Data2;
				ChannelStates[ReceivedMIDIEvent.Data1 & 0x0F].Velocity = ReceivedMIDIEvent.Data3;

				LEDs_SetAllLEDs(LEDS_LED1);
			}
			else if (ReceivedMIDIEvent.Command == (MIDI_COMMAND_NOTE_OFF >> 4))
			{
				ChannelStates[ReceivedMIDIEvent.Data1 & 0x0F].Velocity = 0;
				
				LEDs_SetAllLEDs(LEDS_NO_LEDS);
			}
		}

		/* Check if the sample reload timer period has elapsed, and that the USB bus is ready for a new sample */
		if (TIFR0 & (1 << OCF0A))
		{
			/* Clear the sample reload timer */
			TIFR0 |= (1 << OCF0A);

			uint8_t OutputSample = 0;
			
			/* Loop through the channels (excluding percussion channel 10) and generate next sample */
			for (uint8_t Channel = 0; Channel < 9; Channel++)
			{
				/* Channel only contributes if it is not muted */
				if (ChannelStates[Channel].Velocity)
				{
					/* Fetch the current sample from the sine lookup table */
					uint8_t TableValue = pgm_read_byte(&SineTable[ChannelStates[Channel].CurrentPos]);
				
					/* Scale sample value by the velocity of the channel */
					TableValue = ((uint16_t)TableValue << 6) / ChannelStates[Channel].Velocity;
					
					/* Add the sample to the output waveform */
					OutputSample += TableValue;
				}
				
				/* Calculate next sample table position for this channel */
				ChannelStates[Channel].CurrentPos += ChannelStates[Channel].Pitch;
			}
			
			/* Output the sample to the PWM timer */
			OCR3A = OutputSample;
		}
	
		MIDI_Device_USBTask(&Keyboard_MIDI_Interface);
		USB_USBTask();
	}
}

/** 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 */
	LEDs_Init();
	USB_Init();

	/* Sample reload timer initialization */
	OCR0A   = (F_CPU / 8 / AUDIO_SAMPLE_FREQUENCY) - 1;
	TCCR0A  = (1 << WGM01);  // CTC mode
	TCCR0B  = (1 << CS01);   // Fcpu/8 speed

	/* PWM speaker timer initialization */
	TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)); // Set on match, clear on TOP
	TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, Fcpu speed
}

/** Event handler for the library USB Connection event. */
void EVENT_USB_Device_Connect(void)
{
	LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);

	/* Set speaker as output */
	DDRC |= (1 << 6);
}

/** Event handler for the library USB Disconnection event. */
void EVENT_USB_Device_Disconnect(void)
{
	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);

	/* Set speaker as input to reduce current draw */
	DDRC &= ~(1 << 6);
}

/** Event handler for the library USB Configuration Changed event. */
void EVENT_USB_Device_ConfigurationChanged(void)
{
	LEDs_SetAllLEDs(LEDMASK_USB_READY);
	
	if (!(MIDI_Device_ConfigureEndpoints(&Keyboard_MIDI_Interface)))
	  LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
}

/** Event handler for the library USB Unhandled Control Request event. */
void EVENT_USB_Device_UnhandledControlRequest(void)
{
	MIDI_Device_ProcessControlRequest(&Keyboard_MIDI_Interface);
}