quantum/audio/audio.c

   1 /* Copyright 2016 Jack Humbert
   2  *
   3  * This program is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <stdio.h>
  18 #include <string.h>
  19 //#include <math.h>
  20 #include <avr/pgmspace.h>
  21 #include <avr/interrupt.h>
  22 #include <avr/io.h>
  23 #include "print.h"
  24 #include "audio.h"
  25 #include "keymap.h"
  26
  27 #include "eeconfig.h"
  28
  29 #define CPU_PRESCALER 8
  30
  31 // -----------------------------------------------------------------------------
  32 // Timer Abstractions
  33 // -----------------------------------------------------------------------------
  34
  35 // TIMSK3 - Timer/Counter #3 Interrupt Mask Register
  36 // Turn on/off 3A interputs, stopping/enabling the ISR calls
  37 #ifdef C6_AUDIO
  38     #define ENABLE_AUDIO_COUNTER_3_ISR TIMSK3 |= _BV(OCIE3A)
  39     #define DISABLE_AUDIO_COUNTER_3_ISR TIMSK3 &= ~_BV(OCIE3A)
  40 #endif
  41
  42 #ifdef B5_AUDIO
  43     #define ENABLE_AUDIO_COUNTER_1_ISR TIMSK1 |= _BV(OCIE1A)
  44     #define DISABLE_AUDIO_COUNTER_1_ISR TIMSK1 &= ~_BV(OCIE1A)
  45 #endif
  46
  47 // TCCR3A: Timer/Counter #3 Control Register
  48 // Compare Output Mode (COM3An) = 0b00 = Normal port operation, OC3A disconnected from PC6
  49
  50 #ifdef C6_AUDIO
  51     #define ENABLE_AUDIO_COUNTER_3_OUTPUT TCCR3A |= _BV(COM3A1);
  52     #define DISABLE_AUDIO_COUNTER_3_OUTPUT TCCR3A &= ~(_BV(COM3A1) | _BV(COM3A0));
  53 #endif
  54
  55 #ifdef B5_AUDIO
  56     #define ENABLE_AUDIO_COUNTER_1_OUTPUT TCCR1A |= _BV(COM1A1);
  57     #define DISABLE_AUDIO_COUNTER_1_OUTPUT TCCR1A &= ~(_BV(COM1A1) | _BV(COM1A0));
  58 #endif
  59
  60 // Fast PWM Mode Controls
  61
  62 #ifdef C6_AUDIO
  63     #define TIMER_3_PERIOD     ICR3
  64     #define TIMER_3_DUTY_CYCLE OCR3A
  65 #endif
  66
  67 #ifdef B5_AUDIO
  68     #define TIMER_1_PERIOD     ICR1
  69     #define TIMER_1_DUTY_CYCLE OCR1A
  70 #endif
  71
  72
  73 // -----------------------------------------------------------------------------
  74
  75
  76 int voices = 0;
  77 int voice_place = 0;
  78 float frequency = 0;
  79 float frequency_alt = 0;
  80 int volume = 0;
  81 long position = 0;
  82
  83 float frequencies[8] = {0, 0, 0, 0, 0, 0, 0, 0};
  84 int volumes[8] = {0, 0, 0, 0, 0, 0, 0, 0};
  85 bool sliding = false;
  86
  87 float place = 0;
  88
  89 uint8_t * sample;
  90 uint16_t sample_length = 0;
  91
  92 bool     playing_notes = false;
  93 bool     playing_note = false;
  94 float    note_frequency = 0;
  95 float    note_length = 0;
  96 uint8_t  note_tempo = TEMPO_DEFAULT;
  97 float    note_timbre = TIMBRE_DEFAULT;
  98 uint16_t note_position = 0;
  99 float (* notes_pointer)[][2];
 100 uint16_t notes_count;
 101 bool     notes_repeat;
 102 bool     note_resting = false;
 103
 104 uint8_t current_note = 0;
 105 uint8_t rest_counter = 0;
 106
 107 #ifdef VIBRATO_ENABLE
 108 float vibrato_counter = 0;
 109 float vibrato_strength = .5;
 110 float vibrato_rate = 0.125;
 111 #endif
 112
 113 float polyphony_rate = 0;
 114
 115 static bool audio_initialized = false;
 116
 117 audio_config_t audio_config;
 118
 119 uint16_t envelope_index = 0;
 120 bool glissando = true;
 121
 122 #ifndef STARTUP_SONG
 123     #define STARTUP_SONG SONG(STARTUP_SOUND)
 124 #endif
 125 float startup_song[][2] = STARTUP_SONG;
 126
 127 void audio_init()
 128 {
 129
 130     if (audio_initialized)
 131         return;
 132
 133     // Check EEPROM
 134     if (!eeconfig_is_enabled())
 135     {
 136         eeconfig_init();
 137     }
 138     audio_config.raw = eeconfig_read_audio();
 139
 140     // Set port PC6 (OC3A and /OC4A) as output
 141
 142     #ifdef C6_AUDIO
 143         DDRC |= _BV(PORTC6);
 144     #else
 145         DDRC |= _BV(PORTC6);
 146         PORTC &= ~_BV(PORTC6);
 147     #endif
 148
 149     #ifdef B5_AUDIO
 150         DDRB |= _BV(PORTB5);
 151     #else
 152         DDRB |= _BV(PORTB5);
 153         PORTB &= ~_BV(PORTB5);
 154     #endif
 155
 156     #ifdef C6_AUDIO
 157         DISABLE_AUDIO_COUNTER_3_ISR;
 158     #endif
 159
 160     #ifdef B5_AUDIO
 161         DISABLE_AUDIO_COUNTER_1_ISR;
 162     #endif
 163
 164     // TCCR3A / TCCR3B: Timer/Counter #3 Control Registers
 165     // Compare Output Mode (COM3An) = 0b00 = Normal port operation, OC3A disconnected from PC6
 166     // Waveform Generation Mode (WGM3n) = 0b1110 = Fast PWM Mode 14 (Period = ICR3, Duty Cycle = OCR3A)
 167     // Clock Select (CS3n) = 0b010 = Clock / 8
 168
 169     #ifdef C6_AUDIO
 170         TCCR3A = (0 << COM3A1) | (0 << COM3A0) | (1 << WGM31) | (0 << WGM30);
 171         TCCR3B = (1 << WGM33)  | (1 << WGM32)  | (0 << CS32)  | (1 << CS31) | (0 << CS30);
 172     #endif
 173
 174     #ifdef B5_AUDIO
 175         TCCR1A = (0 << COM1A1) | (0 << COM1A0) | (1 << WGM11) | (0 << WGM10);
 176         TCCR1B = (1 << WGM13)  | (1 << WGM12)  | (0 << CS12)  | (1 << CS11) | (0 << CS10);
 177     #endif
 178
 179     audio_initialized = true;
 180
 181     if (audio_config.enable) {
 182         PLAY_SONG(startup_song);
 183     }
 184
 185 }
 186
 187 void stop_all_notes()
 188 {
 189     dprintf("audio stop all notes");
 190
 191     if (!audio_initialized) {
 192         audio_init();
 193     }
 194     voices = 0;
 195
 196
 197     #ifdef C6_AUDIO
 198         DISABLE_AUDIO_COUNTER_3_ISR;
 199         DISABLE_AUDIO_COUNTER_3_OUTPUT;
 200     #endif
 201
 202     #ifdef B5_AUDIO
 203         DISABLE_AUDIO_COUNTER_1_ISR;
 204         DISABLE_AUDIO_COUNTER_1_OUTPUT;
 205     #endif
 206
 207     playing_notes = false;
 208     playing_note = false;
 209     frequency = 0;
 210     frequency_alt = 0;
 211     volume = 0;
 212
 213     for (uint8_t i = 0; i < 8; i++)
 214     {
 215         frequencies[i] = 0;
 216         volumes[i] = 0;
 217     }
 218 }
 219
 220 void stop_note(float freq)
 221 {
 222     dprintf("audio stop note freq=%d", (int)freq);
 223
 224     if (playing_note) {
 225         if (!audio_initialized) {
 226             audio_init();
 227         }
 228         for (int i = 7; i >= 0; i--) {
 229             if (frequencies[i] == freq) {
 230                 frequencies[i] = 0;
 231                 volumes[i] = 0;
 232                 for (int j = i; (j < 7); j++) {
 233                     frequencies[j] = frequencies[j+1];
 234                     frequencies[j+1] = 0;
 235                     volumes[j] = volumes[j+1];
 236                     volumes[j+1] = 0;
 237                 }
 238                 break;
 239             }
 240         }
 241         voices--;
 242         if (voices < 0)
 243             voices = 0;
 244         if (voice_place >= voices) {
 245             voice_place = 0;
 246         }
 247         if (voices == 0) {
 248             #ifdef C6_AUDIO
 249                 DISABLE_AUDIO_COUNTER_3_ISR;
 250                 DISABLE_AUDIO_COUNTER_3_OUTPUT;
 251             #endif
 252             #ifdef B5_AUDIO
 253                 DISABLE_AUDIO_COUNTER_1_ISR;
 254                 DISABLE_AUDIO_COUNTER_1_OUTPUT;
 255             #endif
 256             frequency = 0;
 257             frequency_alt = 0;
 258             volume = 0;
 259             playing_note = false;
 260         }
 261     }
 262 }
 263
 264 #ifdef VIBRATO_ENABLE
 265
 266 float mod(float a, int b)
 267 {
 268     float r = fmod(a, b);
 269     return r < 0 ? r + b : r;
 270 }
 271
 272 float vibrato(float average_freq) {
 273     #ifdef VIBRATO_STRENGTH_ENABLE
 274         float vibrated_freq = average_freq * pow(vibrato_lut[(int)vibrato_counter], vibrato_strength);
 275     #else
 276         float vibrated_freq = average_freq * vibrato_lut[(int)vibrato_counter];
 277     #endif
 278     vibrato_counter = mod((vibrato_counter + vibrato_rate * (1.0 + 440.0/average_freq)), VIBRATO_LUT_LENGTH);
 279     return vibrated_freq;
 280 }
 281
 282 #endif
 283
 284 #ifdef C6_AUDIO
 285 ISR(TIMER3_COMPA_vect)
 286 {
 287     float freq;
 288
 289     if (playing_note) {
 290         if (voices > 0) {
 291
 292             #ifdef B5_AUDIO
 293             float freq_alt = 0;
 294                 if (voices > 1) {
 295                     if (polyphony_rate == 0) {
 296                         if (glissando) {
 297                             if (frequency_alt != 0 && frequency_alt < frequencies[voices - 2] && frequency_alt < frequencies[voices - 2] * pow(2, -440/frequencies[voices - 2]/12/2)) {
 298                                 frequency_alt = frequency_alt * pow(2, 440/frequency_alt/12/2);
 299                             } else if (frequency_alt != 0 && frequency_alt > frequencies[voices - 2] && frequency_alt > frequencies[voices - 2] * pow(2, 440/frequencies[voices - 2]/12/2)) {
 300                                 frequency_alt = frequency_alt * pow(2, -440/frequency_alt/12/2);
 301                             } else {
 302                                 frequency_alt = frequencies[voices - 2];
 303                             }
 304                         } else {
 305                             frequency_alt = frequencies[voices - 2];
 306                         }
 307
 308                         #ifdef VIBRATO_ENABLE
 309                             if (vibrato_strength > 0) {
 310                                 freq_alt = vibrato(frequency_alt);
 311                             } else {
 312                                 freq_alt = frequency_alt;
 313                             }
 314                         #else
 315                             freq_alt = frequency_alt;
 316                         #endif
 317                     }
 318
 319                     if (envelope_index < 65535) {
 320                         envelope_index++;
 321                     }
 322
 323                     freq_alt = voice_envelope(freq_alt);
 324
 325                     if (freq_alt < 30.517578125) {
 326                         freq_alt = 30.52;
 327                     }
 328
 329                     TIMER_1_PERIOD = (uint16_t)(((float)F_CPU) / (freq_alt * CPU_PRESCALER));
 330                     TIMER_1_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq_alt * CPU_PRESCALER)) * note_timbre);
 331                 }
 332             #endif
 333
 334             if (polyphony_rate > 0) {
 335                 if (voices > 1) {
 336                     voice_place %= voices;
 337                     if (place++ > (frequencies[voice_place] / polyphony_rate / CPU_PRESCALER)) {
 338                         voice_place = (voice_place + 1) % voices;
 339                         place = 0.0;
 340                     }
 341                 }
 342
 343                 #ifdef VIBRATO_ENABLE
 344                     if (vibrato_strength > 0) {
 345                         freq = vibrato(frequencies[voice_place]);
 346                     } else {
 347                         freq = frequencies[voice_place];
 348                     }
 349                 #else
 350                     freq = frequencies[voice_place];
 351                 #endif
 352             } else {
 353                 if (glissando) {
 354                     if (frequency != 0 && frequency < frequencies[voices - 1] && frequency < frequencies[voices - 1] * pow(2, -440/frequencies[voices - 1]/12/2)) {
 355                         frequency = frequency * pow(2, 440/frequency/12/2);
 356                     } else if (frequency != 0 && frequency > frequencies[voices - 1] && frequency > frequencies[voices - 1] * pow(2, 440/frequencies[voices - 1]/12/2)) {
 357                         frequency = frequency * pow(2, -440/frequency/12/2);
 358                     } else {
 359                         frequency = frequencies[voices - 1];
 360                     }
 361                 } else {
 362                     frequency = frequencies[voices - 1];
 363                 }
 364
 365                 #ifdef VIBRATO_ENABLE
 366                     if (vibrato_strength > 0) {
 367                         freq = vibrato(frequency);
 368                     } else {
 369                         freq = frequency;
 370                     }
 371                 #else
 372                     freq = frequency;
 373                 #endif
 374             }
 375
 376             if (envelope_index < 65535) {
 377                 envelope_index++;
 378             }
 379
 380             freq = voice_envelope(freq);
 381
 382             if (freq < 30.517578125) {
 383                 freq = 30.52;
 384             }
 385
 386             TIMER_3_PERIOD = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
 387             TIMER_3_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);
 388         }
 389     }
 390
 391     if (playing_notes) {
 392         if (note_frequency > 0) {
 393             #ifdef VIBRATO_ENABLE
 394                 if (vibrato_strength > 0) {
 395                     freq = vibrato(note_frequency);
 396                 } else {
 397                     freq = note_frequency;
 398                 }
 399             #else
 400                     freq = note_frequency;
 401             #endif
 402
 403             if (envelope_index < 65535) {
 404                 envelope_index++;
 405             }
 406             freq = voice_envelope(freq);
 407
 408             TIMER_3_PERIOD = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
 409             TIMER_3_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);
 410         } else {
 411             TIMER_3_PERIOD = 0;
 412             TIMER_3_DUTY_CYCLE = 0;
 413         }
 414
 415         note_position++;
 416         bool end_of_note = false;
 417         if (TIMER_3_PERIOD > 0) {
 418             if (!note_resting)
 419                 end_of_note = (note_position >= (note_length / TIMER_3_PERIOD * 0xFFFF - 1));
 420             else
 421                 end_of_note = (note_position >= (note_length));
 422         } else {
 423             end_of_note = (note_position >= (note_length));
 424         }
 425
 426         if (end_of_note) {
 427             current_note++;
 428             if (current_note >= notes_count) {
 429                 if (notes_repeat) {
 430                     current_note = 0;
 431                 } else {
 432                     DISABLE_AUDIO_COUNTER_3_ISR;
 433                     DISABLE_AUDIO_COUNTER_3_OUTPUT;
 434                     playing_notes = false;
 435                     return;
 436                 }
 437             }
 438             if (!note_resting) {
 439                 note_resting = true;
 440                 current_note--;
 441                 if ((*notes_pointer)[current_note][0] == (*notes_pointer)[current_note + 1][0]) {
 442                     note_frequency = 0;
 443                     note_length = 1;
 444                 } else {
 445                     note_frequency = (*notes_pointer)[current_note][0];
 446                     note_length = 1;
 447                 }
 448             } else {
 449                 note_resting = false;
 450                 envelope_index = 0;
 451                 note_frequency = (*notes_pointer)[current_note][0];
 452                 note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
 453             }
 454
 455             note_position = 0;
 456         }
 457     }
 458
 459     if (!audio_config.enable) {
 460         playing_notes = false;
 461         playing_note = false;
 462     }
 463 }
 464 #endif
 465
 466 #ifdef B5_AUDIO
 467 ISR(TIMER1_COMPA_vect)
 468 {
 469     #if defined(B5_AUDIO) && !defined(C6_AUDIO)
 470     float freq = 0;
 471
 472     if (playing_note) {
 473         if (voices > 0) {
 474             if (polyphony_rate > 0) {
 475                 if (voices > 1) {
 476                     voice_place %= voices;
 477                     if (place++ > (frequencies[voice_place] / polyphony_rate / CPU_PRESCALER)) {
 478                         voice_place = (voice_place + 1) % voices;
 479                         place = 0.0;
 480                     }
 481                 }
 482
 483                 #ifdef VIBRATO_ENABLE
 484                     if (vibrato_strength > 0) {
 485                         freq = vibrato(frequencies[voice_place]);
 486                     } else {
 487                         freq = frequencies[voice_place];
 488                     }
 489                 #else
 490                     freq = frequencies[voice_place];
 491                 #endif
 492             } else {
 493                 if (glissando) {
 494                     if (frequency != 0 && frequency < frequencies[voices - 1] && frequency < frequencies[voices - 1] * pow(2, -440/frequencies[voices - 1]/12/2)) {
 495                         frequency = frequency * pow(2, 440/frequency/12/2);
 496                     } else if (frequency != 0 && frequency > frequencies[voices - 1] && frequency > frequencies[voices - 1] * pow(2, 440/frequencies[voices - 1]/12/2)) {
 497                         frequency = frequency * pow(2, -440/frequency/12/2);
 498                     } else {
 499                         frequency = frequencies[voices - 1];
 500                     }
 501                 } else {
 502                     frequency = frequencies[voices - 1];
 503                 }
 504
 505                 #ifdef VIBRATO_ENABLE
 506                     if (vibrato_strength > 0) {
 507                         freq = vibrato(frequency);
 508                     } else {
 509                         freq = frequency;
 510                     }
 511                 #else
 512                     freq = frequency;
 513                 #endif
 514             }
 515
 516             if (envelope_index < 65535) {
 517                 envelope_index++;
 518             }
 519
 520             freq = voice_envelope(freq);
 521
 522             if (freq < 30.517578125) {
 523                 freq = 30.52;
 524             }
 525
 526             TIMER_1_PERIOD = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
 527             TIMER_1_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);
 528         }
 529     }
 530
 531     if (playing_notes) {
 532         if (note_frequency > 0) {
 533             #ifdef VIBRATO_ENABLE
 534                 if (vibrato_strength > 0) {
 535                     freq = vibrato(note_frequency);
 536                 } else {
 537                     freq = note_frequency;
 538                 }
 539             #else
 540                     freq = note_frequency;
 541             #endif
 542
 543             if (envelope_index < 65535) {
 544                 envelope_index++;
 545             }
 546             freq = voice_envelope(freq);
 547
 548             TIMER_1_PERIOD = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
 549             TIMER_1_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);
 550         } else {
 551             TIMER_1_PERIOD = 0;
 552             TIMER_1_DUTY_CYCLE = 0;
 553         }
 554
 555         note_position++;
 556         bool end_of_note = false;
 557         if (TIMER_1_PERIOD > 0) {
 558             end_of_note = (note_position >= (note_length / TIMER_1_PERIOD * 0xFFFF - 1));
 559         } else {
 560             end_of_note = (note_position >= (note_length));
 561         }
 562
 563         if (end_of_note) {
 564             current_note++;
 565             if (current_note >= notes_count) {
 566                 if (notes_repeat) {
 567                     current_note = 0;
 568                 } else {
 569                     DISABLE_AUDIO_COUNTER_1_ISR;
 570                     DISABLE_AUDIO_COUNTER_1_OUTPUT;
 571                     playing_notes = false;
 572                     return;
 573                 }
 574             }
 575             if (!note_resting) {
 576                 note_resting = true;
 577                 current_note--;
 578                 if ((*notes_pointer)[current_note][0] == (*notes_pointer)[current_note + 1][0]) {
 579                     note_frequency = 0;
 580                     note_length = 1;
 581                 } else {
 582                     note_frequency = (*notes_pointer)[current_note][0];
 583                     note_length = 1;
 584                 }
 585             } else {
 586                 note_resting = false;
 587                 envelope_index = 0;
 588                 note_frequency = (*notes_pointer)[current_note][0];
 589                 note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
 590             }
 591
 592             note_position = 0;
 593         }
 594     }
 595
 596     if (!audio_config.enable) {
 597         playing_notes = false;
 598         playing_note = false;
 599     }
 600 #endif
 601 }
 602 #endif
 603
 604 void play_note(float freq, int vol) {
 605
 606     dprintf("audio play note freq=%d vol=%d", (int)freq, vol);
 607
 608     if (!audio_initialized) {
 609         audio_init();
 610     }
 611
 612     if (audio_config.enable && voices < 8) {
 613         #ifdef C6_AUDIO
 614             DISABLE_AUDIO_COUNTER_3_ISR;
 615         #endif
 616         #ifdef B5_AUDIO
 617             DISABLE_AUDIO_COUNTER_1_ISR;
 618         #endif
 619
 620         // Cancel notes if notes are playing
 621         if (playing_notes)
 622             stop_all_notes();
 623
 624         playing_note = true;
 625
 626         envelope_index = 0;
 627
 628         if (freq > 0) {
 629             frequencies[voices] = freq;
 630             volumes[voices] = vol;
 631             voices++;
 632         }
 633
 634         #ifdef C6_AUDIO
 635             ENABLE_AUDIO_COUNTER_3_ISR;
 636             ENABLE_AUDIO_COUNTER_3_OUTPUT;
 637         #endif
 638         #ifdef B5_AUDIO
 639             #ifdef C6_AUDIO
 640             if (voices > 1) {
 641                 ENABLE_AUDIO_COUNTER_1_ISR;
 642                 ENABLE_AUDIO_COUNTER_1_OUTPUT;
 643             }
 644             #else
 645             ENABLE_AUDIO_COUNTER_1_ISR;
 646             ENABLE_AUDIO_COUNTER_1_OUTPUT;
 647             #endif
 648         #endif
 649     }
 650
 651 }
 652
 653 void play_notes(float (*np)[][2], uint16_t n_count, bool n_repeat)
 654 {
 655
 656     if (!audio_initialized) {
 657         audio_init();
 658     }
 659
 660     if (audio_config.enable) {
 661
 662         #ifdef C6_AUDIO
 663             DISABLE_AUDIO_COUNTER_3_ISR;
 664         #endif
 665         #ifdef B5_AUDIO
 666             DISABLE_AUDIO_COUNTER_1_ISR;
 667         #endif
 668
 669         // Cancel note if a note is playing
 670         if (playing_note)
 671             stop_all_notes();
 672
 673         playing_notes = true;
 674
 675         notes_pointer = np;
 676         notes_count = n_count;
 677         notes_repeat = n_repeat;
 678
 679         place = 0;
 680         current_note = 0;
 681
 682         note_frequency = (*notes_pointer)[current_note][0];
 683         note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
 684         note_position = 0;
 685
 686
 687         #ifdef C6_AUDIO
 688             ENABLE_AUDIO_COUNTER_3_ISR;
 689             ENABLE_AUDIO_COUNTER_3_OUTPUT;
 690         #endif
 691         #ifdef B5_AUDIO
 692             #ifndef C6_AUDIO
 693             ENABLE_AUDIO_COUNTER_1_ISR;
 694             ENABLE_AUDIO_COUNTER_1_OUTPUT;
 695             #endif
 696         #endif
 697     }
 698
 699 }
 700
 701 bool is_playing_notes(void) {
 702     return playing_notes;
 703 }
 704
 705 bool is_audio_on(void) {
 706     return (audio_config.enable != 0);
 707 }
 708
 709 void audio_toggle(void) {
 710     audio_config.enable ^= 1;
 711     eeconfig_update_audio(audio_config.raw);
 712     if (audio_config.enable)
 713         audio_on_user();
 714 }
 715
 716 void audio_on(void) {
 717     audio_config.enable = 1;
 718     eeconfig_update_audio(audio_config.raw);
 719     audio_on_user();
 720 }
 721
 722 void audio_off(void) {
 723     audio_config.enable = 0;
 724     eeconfig_update_audio(audio_config.raw);
 725 }
 726
 727 #ifdef VIBRATO_ENABLE
 728
 729 // Vibrato rate functions
 730
 731 void set_vibrato_rate(float rate) {
 732     vibrato_rate = rate;
 733 }
 734
 735 void increase_vibrato_rate(float change) {
 736     vibrato_rate *= change;
 737 }
 738
 739 void decrease_vibrato_rate(float change) {
 740     vibrato_rate /= change;
 741 }
 742
 743 #ifdef VIBRATO_STRENGTH_ENABLE
 744
 745 void set_vibrato_strength(float strength) {
 746     vibrato_strength = strength;
 747 }
 748
 749 void increase_vibrato_strength(float change) {
 750     vibrato_strength *= change;
 751 }
 752
 753 void decrease_vibrato_strength(float change) {
 754     vibrato_strength /= change;
 755 }
 756
 757 #endif  /* VIBRATO_STRENGTH_ENABLE */
 758
 759 #endif /* VIBRATO_ENABLE */
 760
 761 // Polyphony functions
 762
 763 void set_polyphony_rate(float rate) {
 764     polyphony_rate = rate;
 765 }
 766
 767 void enable_polyphony() {
 768     polyphony_rate = 5;
 769 }
 770
 771 void disable_polyphony() {
 772     polyphony_rate = 0;
 773 }
 774
 775 void increase_polyphony_rate(float change) {
 776     polyphony_rate *= change;
 777 }
 778
 779 void decrease_polyphony_rate(float change) {
 780     polyphony_rate /= change;
 781 }
 782
 783 // Timbre function
 784
 785 void set_timbre(float timbre) {
 786     note_timbre = timbre;
 787 }
 788
 789 // Tempo functions
 790
 791 void set_tempo(uint8_t tempo) {
 792     note_tempo = tempo;
 793 }
 794
 795 void decrease_tempo(uint8_t tempo_change) {
 796     note_tempo += tempo_change;
 797 }
 798
 799 void increase_tempo(uint8_t tempo_change) {
 800     if (note_tempo - tempo_change < 10) {
 801         note_tempo = 10;
 802     } else {
 803         note_tempo -= tempo_change;
 804     }
 805 }