Projects/MIDIToneGenerator/MIDIToneGenerator.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2012.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2012  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 disclaim 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
  49                                 .DataINEndpointNumber      = MIDI_STREAM_IN_EPNUM,
  50                                 .DataINEndpointSize        = MIDI_STREAM_EPSIZE,
  51                                 .DataINEndpointDoubleBank  = false,
  52
  53                                 .DataOUTEndpointNumber     = MIDI_STREAM_OUT_EPNUM,
  54                                 .DataOUTEndpointSize       = MIDI_STREAM_EPSIZE,
  55                                 .DataOUTEndpointDoubleBank = false,
  56                         },
  57         };
  58
  59 /** 8-bit 256 entry Sine Wave lookup table */
  60 static const uint8_t SineTable[256] =
  61 {
  62         128, 131, 134, 137, 140, 143, 146, 149, 152, 156, 159, 162, 165, 168, 171, 174,
  63         176, 179, 182, 185, 188, 191, 193, 196, 199, 201, 204, 206, 209, 211, 213, 216,
  64         218, 220, 222, 224, 226, 228, 230, 232, 234, 236, 237, 239, 240, 242, 243, 245,
  65         246, 247, 248, 249, 250, 251, 252, 252, 253, 254, 254, 255, 255, 255, 255, 255,
  66         255, 255, 255, 255, 255, 255, 254, 254, 253, 252, 252, 251, 250, 249, 248, 247,
  67         246, 245, 243, 242, 240, 239, 237, 236, 234, 232, 230, 228, 226, 224, 222, 220,
  68         218, 216, 213, 211, 209, 206, 204, 201, 199, 196, 193, 191, 188, 185, 182, 179,
  69         176, 174, 171, 168, 165, 162, 159, 156, 152, 149, 146, 143, 140, 137, 134, 131,
  70         128, 124, 121, 118, 115, 112, 109, 106, 103,  99,  96,  93,  90,  87,  84,  81,
  71          79,  76,  73,  70,  67,  64,  62,  59,  56,  54,  51,  49,  46,  44,  42,  39,
  72          37,  35,  33,  31,  29,  27,  25,  23,  21,  19,  18,  16,  15,  13,  12,  10,
  73           9,   8,   7,   6,   5,   4,   3,   3,   2,   1,   1,   0,   0,   0,   0,   0,
  74           0,   0,   0,   0,   0,   0,   1,   1,   2,   3,   3,   4,   5,   6,   7,   8,
  75           9,  10,  12,  13,  15,  16,  18,  19,  21,  23,  25,  27,  29,  31,  33,  35,
  76          37,  39,  42,  44,  46,  49,  51,  54,  56,  59,  62,  64,  67,  70,  73,  76,
  77          79,  81,  84,  87,  90,  93,  96,  99, 103, 106, 109, 112, 115, 118, 121, 124,
  78 };
  79
  80 /** Array of structures describing each note being generated */
  81 static DDSNoteData NoteData[MAX_SIMULTANEOUS_NOTES];
  82
  83
  84 /** Main program entry point. This routine contains the overall program flow, including initial
  85  *  setup of all components and the main program loop.
  86  */
  87 int main(void)
  88 {
  89         SetupHardware();
  90
  91         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  92         sei();
  93
  94         for (;;)
  95         {
  96                 MIDI_EventPacket_t ReceivedMIDIEvent;
  97                 if (MIDI_Device_ReceiveEventPacket(&Keyboard_MIDI_Interface, &ReceivedMIDIEvent))
  98                 {
  99                         if ((ReceivedMIDIEvent.Command == (MIDI_COMMAND_NOTE_ON >> 4)) && ((ReceivedMIDIEvent.Data1 & 0x0F) == 0))
 100                         {
 101                                 DDSNoteData* LRUNoteStruct = &NoteData[0];
 102
 103                                 /* Find a free entry in the note table to use for the note being turned on */
 104                                 for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)
 105                                 {
 106                                         /* Check if the note is unused */
 107                                         if (!(NoteData[i].Pitch))
 108                                         {
 109                                                 /* If a note is unused, it's age is essentially infinite - always prefer unused not entries */
 110                                                 LRUNoteStruct = &NoteData[i];
 111                                                 break;
 112                                         }
 113                                         else if (NoteData[i].LRUAge >= LRUNoteStruct->LRUAge)
 114                                         {
 115                                                 /* If an older entry that the current entry has been found, prefer overwriting that one */
 116                                                 LRUNoteStruct = &NoteData[i];
 117                                         }
 118
 119                                         NoteData[i].LRUAge++;
 120                                 }
 121
 122                                 /* Update the oldest note entry with the new note data and reset its age */
 123                                 LRUNoteStruct->Pitch          = ReceivedMIDIEvent.Data2;
 124                                 LRUNoteStruct->TableIncrement = (uint32_t)(BASE_INCREMENT * SCALE_FACTOR) +
 125                                                                          ((uint32_t)(BASE_INCREMENT * NOTE_OCTIVE_RATIO * SCALE_FACTOR) *
 126                                                                           (ReceivedMIDIEvent.Data2 - BASE_PITCH_INDEX));
 127                                 LRUNoteStruct->TablePosition  = 0;
 128                                 LRUNoteStruct->LRUAge         = 0;
 129
 130                                 /* Turn on indicator LED to indicate note generation activity */
 131                                 LEDs_SetAllLEDs(LEDS_LED1);
 132                         }
 133                         else if ((ReceivedMIDIEvent.Command == (MIDI_COMMAND_NOTE_OFF >> 4)) && ((ReceivedMIDIEvent.Data1 & 0x0F) == 0))
 134                         {
 135                                 bool FoundActiveNote = false;
 136
 137                                 /* Find the note in the note table to turn off */
 138                                 for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)
 139                                 {
 140                                         if (NoteData[i].Pitch == ReceivedMIDIEvent.Data2)
 141                                           NoteData[i].Pitch = 0;
 142                                         else if (NoteData[i].Pitch)
 143                                           FoundActiveNote   = true;
 144                                 }
 145
 146                                 /* If all notes off, turn off the indicator LED */
 147                                 if (!(FoundActiveNote))
 148                                   LEDs_SetAllLEDs(LEDS_NO_LEDS);
 149                         }
 150                 }
 151
 152                 MIDI_Device_USBTask(&Keyboard_MIDI_Interface);
 153                 USB_USBTask();
 154         }
 155 }
 156
 157 /** ISR to handle the reloading of the PWM timer with the next sample. */
 158 ISR(TIMER0_COMPA_vect, ISR_BLOCK)
 159 {
 160         uint16_t MixedSample = 0;
 161
 162         /* Sum together all the active notes to form a single sample */
 163         for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)
 164         {
 165                 /* A non-zero pitch indicates the note is active */
 166                 if (NoteData[i].Pitch)
 167                 {
 168                         /* Use the top 8 bits of the table position as the sample table index */
 169                         uint8_t TableIndex = (NoteData[i].TablePosition >> 24);
 170
 171                         /* Add the new tone sample to the accumulator and increment the table position */
 172                         MixedSample += SineTable[TableIndex];
 173                         NoteData[i].TablePosition += NoteData[i].TableIncrement;
 174                 }
 175         }
 176
 177         /* Output clamped mixed sample value to the PWM */
 178         OCR3A = (MixedSample <= 0xFF) ? MixedSample : 0xFF;
 179 }
 180
 181 /** Configures the board hardware and chip peripherals for the demo's functionality. */
 182 void SetupHardware(void)
 183 {
 184         /* Disable watchdog if enabled by bootloader/fuses */
 185         MCUSR &= ~(1 << WDRF);
 186         wdt_disable();
 187
 188         /* Disable clock division */
 189         clock_prescale_set(clock_div_1);
 190
 191         /* Hardware Initialization */
 192         LEDs_Init();
 193         USB_Init();
 194
 195         /* Sample reload timer initialization */
 196         TIMSK0  = (1 << OCIE0A);
 197         OCR0A   = (VIRTUAL_SAMPLE_TABLE_SIZE / 8);
 198         TCCR0A  = (1 << WGM01);  // CTC mode
 199         TCCR0B  = (1 << CS01);   // Fcpu/8 speed
 200
 201         /* Set speaker as output */
 202         DDRC |= (1 << 6);
 203
 204         /* PWM speaker timer initialization */
 205         TCCR3A  = ((1 << WGM31) | (1 << COM3A1) | (1 << COM3A0)); // Set on match, clear on TOP
 206         TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, Fcpu speed
 207 }
 208
 209 /** Event handler for the library USB Connection event. */
 210 void EVENT_USB_Device_Connect(void)
 211 {
 212         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 213
 214         /* Set speaker as output */
 215         DDRC |= (1 << 6);
 216 }
 217
 218 /** Event handler for the library USB Disconnection event. */
 219 void EVENT_USB_Device_Disconnect(void)
 220 {
 221         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 222
 223         /* Disable any notes currently being played */
 224         for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)
 225           NoteData[i].Pitch = 0;
 226
 227         /* Set speaker as input to reduce current draw */
 228         DDRC &= ~(1 << 6);
 229 }
 230
 231 /** Event handler for the library USB Configuration Changed event. */
 232 void EVENT_USB_Device_ConfigurationChanged(void)
 233 {
 234         bool ConfigSuccess = true;
 235
 236         ConfigSuccess &= MIDI_Device_ConfigureEndpoints(&Keyboard_MIDI_Interface);
 237
 238         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 239 }
 240
 241 /** Event handler for the library USB Control Request event. */
 242 void EVENT_USB_Device_ControlRequest(void)
 243 {
 244         MIDI_Device_ProcessControlRequest(&Keyboard_MIDI_Interface);
 245 }
 246