Projects/MIDIToneGenerator/MIDIToneGenerator.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2013.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2013  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaims all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  Main source file for the MIDI demo. This file contains the main tasks of
  34  *  the demo and is responsible for the initial application hardware configuration.
  35  */
  36
  37 #include "MIDIToneGenerator.h"
  38
  39 /** LUFA MIDI Class driver interface configuration and state information. This structure is
  40  *  passed to all MIDI Class driver functions, so that multiple instances of the same class
  41  *  within a device can be differentiated from one another.
  42  */
  43 USB_ClassInfo_MIDI_Device_t Keyboard_MIDI_Interface =
  44         {
  45                 .Config =
  46                         {
  47                                 .StreamingInterfaceNumber = 1,
  48                                 .DataINEndpoint           =
  49                                         {
  50                                                 .Address          = MIDI_STREAM_IN_EPADDR,
  51                                                 .Size             = MIDI_STREAM_EPSIZE,
  52                                                 .Banks            = 1,
  53                                         },
  54                                 .DataOUTEndpoint           =
  55                                         {
  56                                                 .Address          = MIDI_STREAM_OUT_EPADDR,
  57                                                 .Size             = MIDI_STREAM_EPSIZE,
  58                                                 .Banks            = 1,
  59                                         },
  60                         },
  61         };
  62
  63 /** 8-bit 256 entry Sine Wave lookup table */
  64 static const uint8_t SineTable[256] =
  65 {
  66         128, 131, 134, 137, 140, 143, 146, 149, 152, 156, 159, 162, 165, 168, 171, 174,
  67         176, 179, 182, 185, 188, 191, 193, 196, 199, 201, 204, 206, 209, 211, 213, 216,
  68         218, 220, 222, 224, 226, 228, 230, 232, 234, 236, 237, 239, 240, 242, 243, 245,
  69         246, 247, 248, 249, 250, 251, 252, 252, 253, 254, 254, 255, 255, 255, 255, 255,
  70         255, 255, 255, 255, 255, 255, 254, 254, 253, 252, 252, 251, 250, 249, 248, 247,
  71         246, 245, 243, 242, 240, 239, 237, 236, 234, 232, 230, 228, 226, 224, 222, 220,
  72         218, 216, 213, 211, 209, 206, 204, 201, 199, 196, 193, 191, 188, 185, 182, 179,
  73         176, 174, 171, 168, 165, 162, 159, 156, 152, 149, 146, 143, 140, 137, 134, 131,
  74         128, 124, 121, 118, 115, 112, 109, 106, 103,  99,  96,  93,  90,  87,  84,  81,
  75          79,  76,  73,  70,  67,  64,  62,  59,  56,  54,  51,  49,  46,  44,  42,  39,
  76          37,  35,  33,  31,  29,  27,  25,  23,  21,  19,  18,  16,  15,  13,  12,  10,
  77           9,   8,   7,   6,   5,   4,   3,   3,   2,   1,   1,   0,   0,   0,   0,   0,
  78           0,   0,   0,   0,   0,   0,   1,   1,   2,   3,   3,   4,   5,   6,   7,   8,
  79           9,  10,  12,  13,  15,  16,  18,  19,  21,  23,  25,  27,  29,  31,  33,  35,
  80          37,  39,  42,  44,  46,  49,  51,  54,  56,  59,  62,  64,  67,  70,  73,  76,
  81          79,  81,  84,  87,  90,  93,  96,  99, 103, 106, 109, 112, 115, 118, 121, 124,
  82 };
  83
  84 /** Array of structures describing each note being generated */
  85 static DDSNoteData NoteData[MAX_SIMULTANEOUS_NOTES];
  86
  87
  88 /** Main program entry point. This routine contains the overall program flow, including initial
  89  *  setup of all components and the main program loop.
  90  */
  91 int main(void)
  92 {
  93         SetupHardware();
  94
  95         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  96         GlobalInterruptEnable();
  97
  98         for (;;)
  99         {
 100                 MIDI_EventPacket_t ReceivedMIDIEvent;
 101                 if (MIDI_Device_ReceiveEventPacket(&Keyboard_MIDI_Interface, &ReceivedMIDIEvent))
 102                 {
 103                         if ((ReceivedMIDIEvent.Event == MIDI_EVENT(0, MIDI_COMMAND_NOTE_ON)) && ((ReceivedMIDIEvent.Data1 & 0x0F) == 0))
 104                         {
 105                                 DDSNoteData* LRUNoteStruct = &NoteData[0];
 106
 107                                 /* Find a free entry in the note table to use for the note being turned on */
 108                                 for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)
 109                                 {
 110                                         /* Check if the note is unused */
 111                                         if (!(NoteData[i].Pitch))
 112                                         {
 113                                                 /* If a note is unused, it's age is essentially infinite - always prefer unused not entries */
 114                                                 LRUNoteStruct = &NoteData[i];
 115                                                 break;
 116                                         }
 117                                         else if (NoteData[i].LRUAge >= LRUNoteStruct->LRUAge)
 118                                         {
 119                                                 /* If an older entry that the current entry has been found, prefer overwriting that one */
 120                                                 LRUNoteStruct = &NoteData[i];
 121                                         }
 122
 123                                         NoteData[i].LRUAge++;
 124                                 }
 125
 126                                 /* Update the oldest note entry with the new note data and reset its age */
 127                                 LRUNoteStruct->Pitch          = ReceivedMIDIEvent.Data2;
 128                                 LRUNoteStruct->TableIncrement = (uint32_t)(BASE_INCREMENT * SCALE_FACTOR) +
 129                                                                          ((uint32_t)(BASE_INCREMENT * NOTE_OCTIVE_RATIO * SCALE_FACTOR) *
 130                                                                           (ReceivedMIDIEvent.Data2 - BASE_PITCH_INDEX));
 131                                 LRUNoteStruct->TablePosition  = 0;
 132                                 LRUNoteStruct->LRUAge         = 0;
 133
 134                                 /* Turn on indicator LED to indicate note generation activity */
 135                                 LEDs_SetAllLEDs(LEDS_LED1);
 136                         }
 137                         else if ((ReceivedMIDIEvent.Event == MIDI_EVENT(0, MIDI_COMMAND_NOTE_OFF)) && ((ReceivedMIDIEvent.Data1 & 0x0F) == 0))
 138                         {
 139                                 bool FoundActiveNote = false;
 140
 141                                 /* Find the note in the note table to turn off */
 142                                 for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)
 143                                 {
 144                                         if (NoteData[i].Pitch == ReceivedMIDIEvent.Data2)
 145                                           NoteData[i].Pitch = 0;
 146                                         else if (NoteData[i].Pitch)
 147                                           FoundActiveNote   = true;
 148                                 }
 149
 150                                 /* If all notes off, turn off the indicator LED */
 151                                 if (!(FoundActiveNote))
 152                                   LEDs_SetAllLEDs(LEDS_NO_LEDS);
 153                         }
 154                 }
 155
 156                 MIDI_Device_USBTask(&Keyboard_MIDI_Interface);
 157                 USB_USBTask();
 158         }
 159 }
 160
 161 /** ISR to handle the reloading of the PWM timer with the next sample. */
 162 ISR(TIMER0_COMPA_vect, ISR_BLOCK)
 163 {
 164         uint16_t MixedSample = 0;
 165
 166         /* Sum together all the active notes to form a single sample */
 167         for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)
 168         {
 169                 /* A non-zero pitch indicates the note is active */
 170                 if (NoteData[i].Pitch)
 171                 {
 172                         /* Use the top 8 bits of the table position as the sample table index */
 173                         uint8_t TableIndex = (NoteData[i].TablePosition >> 24);
 174
 175                         /* Add the new tone sample to the accumulator and increment the table position */
 176                         MixedSample += SineTable[TableIndex];
 177                         NoteData[i].TablePosition += NoteData[i].TableIncrement;
 178                 }
 179         }
 180
 181         /* Output clamped mixed sample value to the PWM */
 182         OCR3A = (MixedSample <= 0xFF) ? MixedSample : 0xFF;
 183 }
 184
 185 /** Configures the board hardware and chip peripherals for the demo's functionality. */
 186 void SetupHardware(void)
 187 {
 188         /* Disable watchdog if enabled by bootloader/fuses */
 189         MCUSR &= ~(1 << WDRF);
 190         wdt_disable();
 191
 192         /* Disable clock division */
 193         clock_prescale_set(clock_div_1);
 194
 195         /* Hardware Initialization */
 196         LEDs_Init();
 197         USB_Init();
 198
 199         /* Sample reload timer initialization */
 200         TIMSK0  = (1 << OCIE0A);
 201         OCR0A   = (VIRTUAL_SAMPLE_TABLE_SIZE / 8);
 202         TCCR0A  = (1 << WGM01);  // CTC mode
 203         TCCR0B  = (1 << CS01);   // Fcpu/8 speed
 204
 205         /* Set speaker as output */
 206         DDRC |= (1 << 6);
 207
 208         /* PWM speaker timer initialization */
 209         TCCR3A  = ((1 << WGM31) | (1 << COM3A1) | (1 << COM3A0)); // Set on match, clear on TOP
 210         TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, Fcpu speed
 211 }
 212
 213 /** Event handler for the library USB Connection event. */
 214 void EVENT_USB_Device_Connect(void)
 215 {
 216         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 217
 218         /* Set speaker as output */
 219         DDRC |= (1 << 6);
 220 }
 221
 222 /** Event handler for the library USB Disconnection event. */
 223 void EVENT_USB_Device_Disconnect(void)
 224 {
 225         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 226
 227         /* Disable any notes currently being played */
 228         for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)
 229           NoteData[i].Pitch = 0;
 230
 231         /* Set speaker as input to reduce current draw */
 232         DDRC &= ~(1 << 6);
 233 }
 234
 235 /** Event handler for the library USB Configuration Changed event. */
 236 void EVENT_USB_Device_ConfigurationChanged(void)
 237 {
 238         bool ConfigSuccess = true;
 239
 240         ConfigSuccess &= MIDI_Device_ConfigureEndpoints(&Keyboard_MIDI_Interface);
 241
 242         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 243 }
 244
 245 /** Event handler for the library USB Control Request event. */
 246 void EVENT_USB_Device_ControlRequest(void)
 247 {
 248         MIDI_Device_ProcessControlRequest(&Keyboard_MIDI_Interface);
 249 }
 250