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 #include <stdio.h>
  17 #include <string.h>
  18 //#include <math.h>
  19 #include <avr/pgmspace.h>
  20 #include <avr/interrupt.h>
  21 #include <avr/io.h>
  22 #include "print.h"
  23 #include "audio.h"
  24 #include "keymap.h"
  25
  26 #include "eeconfig.h"
  27
  28 #define CPU_PRESCALER 8
  29
  30 // -----------------------------------------------------------------------------
  31 // Timer Abstractions
  32 // -----------------------------------------------------------------------------
  33
  34 // TIMSK3 - Timer/Counter #3 Interrupt Mask Register
  35 // Turn on/off 3A interputs, stopping/enabling the ISR calls
  36 #ifdef C6_AUDIO
  37     #define ENABLE_AUDIO_COUNTER_3_ISR TIMSK3 |= _BV(OCIE3A)
  38     #define DISABLE_AUDIO_COUNTER_3_ISR TIMSK3 &= ~_BV(OCIE3A)
  39 #endif
  40
  41 #ifdef B5_AUDIO
  42     #define ENABLE_AUDIO_COUNTER_1_ISR TIMSK1 |= _BV(OCIE1A)
  43     #define DISABLE_AUDIO_COUNTER_1_ISR TIMSK1 &= ~_BV(OCIE1A)
  44 #endif
  45
  46 // TCCR3A: Timer/Counter #3 Control Register
  47 // Compare Output Mode (COM3An) = 0b00 = Normal port operation, OC3A disconnected from PC6
  48
  49 #ifdef C6_AUDIO
  50     #define ENABLE_AUDIO_COUNTER_3_OUTPUT TCCR3A |= _BV(COM3A1);
  51     #define DISABLE_AUDIO_COUNTER_3_OUTPUT TCCR3A &= ~(_BV(COM3A1) | _BV(COM3A0));
  52 #endif
  53
  54 #ifdef B5_AUDIO
  55     #define ENABLE_AUDIO_COUNTER_1_OUTPUT TCCR1A |= _BV(COM1A1);
  56     #define DISABLE_AUDIO_COUNTER_1_OUTPUT TCCR1A &= ~(_BV(COM1A1) | _BV(COM1A0));
  57 #endif
  58
  59 // Fast PWM Mode Controls
  60
  61 #ifdef C6_AUDIO
  62     #define TIMER_3_PERIOD     ICR3
  63     #define TIMER_3_DUTY_CYCLE OCR3A
  64 #endif
  65
  66 #ifdef B5_AUDIO
  67     #define TIMER_1_PERIOD     ICR1
  68     #define TIMER_1_DUTY_CYCLE OCR1A
  69 #endif
  70
  71
  72 // -----------------------------------------------------------------------------
  73
  74
  75 int voices = 0;
  76 int voice_place = 0;
  77 float frequency = 0;
  78 float frequency_alt = 0;
  79 int volume = 0;
  80 long position = 0;
  81
  82 float frequencies[8] = {0, 0, 0, 0, 0, 0, 0, 0};
  83 int volumes[8] = {0, 0, 0, 0, 0, 0, 0, 0};
  84 bool sliding = false;
  85
  86 float place = 0;
  87
  88 uint8_t * sample;
  89 uint16_t sample_length = 0;
  90
  91 bool     playing_notes = false;
  92 bool     playing_note = false;
  93 float    note_frequency = 0;
  94 float    note_length = 0;
  95 uint8_t  note_tempo = TEMPO_DEFAULT;
  96 float    note_timbre = TIMBRE_DEFAULT;
  97 uint16_t note_position = 0;
  98 float (* notes_pointer)[][2];
  99 uint16_t notes_count;
 100 bool     notes_repeat;
 101 float    notes_rest;
 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 void audio_init()
 123 {
 124
 125     // Check EEPROM
 126     if (!eeconfig_is_enabled())
 127     {
 128         eeconfig_init();
 129     }
 130     audio_config.raw = eeconfig_read_audio();
 131
 132     // Set port PC6 (OC3A and /OC4A) as output
 133
 134     #ifdef C6_AUDIO
 135         DDRC |= _BV(PORTC6);
 136     #else
 137         DDRC |= _BV(PORTC6);
 138         PORTC &= ~_BV(PORTC6);
 139     #endif
 140
 141     #ifdef B5_AUDIO
 142         DDRB |= _BV(PORTB5);
 143     #else
 144         DDRB |= _BV(PORTB5);
 145         PORTB &= ~_BV(PORTB5);
 146     #endif
 147
 148     #ifdef C6_AUDIO
 149         DISABLE_AUDIO_COUNTER_3_ISR;
 150     #endif
 151
 152     #ifdef B5_AUDIO
 153         DISABLE_AUDIO_COUNTER_1_ISR;
 154     #endif
 155
 156     // TCCR3A / TCCR3B: Timer/Counter #3 Control Registers
 157     // Compare Output Mode (COM3An) = 0b00 = Normal port operation, OC3A disconnected from PC6
 158     // Waveform Generation Mode (WGM3n) = 0b1110 = Fast PWM Mode 14 (Period = ICR3, Duty Cycle = OCR3A)
 159     // Clock Select (CS3n) = 0b010 = Clock / 8
 160
 161     #ifdef C6_AUDIO
 162         TCCR3A = (0 << COM3A1) | (0 << COM3A0) | (1 << WGM31) | (0 << WGM30);
 163         TCCR3B = (1 << WGM33)  | (1 << WGM32)  | (0 << CS32)  | (1 << CS31) | (0 << CS30);
 164     #endif
 165
 166     #ifdef B5_AUDIO
 167         TCCR1A = (0 << COM1A1) | (0 << COM1A0) | (1 << WGM11) | (0 << WGM10);
 168         TCCR1B = (1 << WGM13)  | (1 << WGM12)  | (0 << CS12)  | (1 << CS11) | (0 << CS10);
 169     #endif
 170
 171     audio_initialized = true;
 172 }
 173
 174 void stop_all_notes()
 175 {
 176     dprintf("audio stop all notes");
 177
 178     if (!audio_initialized) {
 179         audio_init();
 180     }
 181     voices = 0;
 182
 183
 184     #ifdef C6_AUDIO
 185         DISABLE_AUDIO_COUNTER_3_ISR;
 186         DISABLE_AUDIO_COUNTER_3_OUTPUT;
 187     #endif
 188
 189     #ifdef B5_AUDIO
 190         DISABLE_AUDIO_COUNTER_1_ISR;
 191         DISABLE_AUDIO_COUNTER_1_OUTPUT;
 192     #endif
 193
 194     playing_notes = false;
 195     playing_note = false;
 196     frequency = 0;
 197     frequency_alt = 0;
 198     volume = 0;
 199
 200     for (uint8_t i = 0; i < 8; i++)
 201     {
 202         frequencies[i] = 0;
 203         volumes[i] = 0;
 204     }
 205 }
 206
 207 void stop_note(float freq)
 208 {
 209     dprintf("audio stop note freq=%d", (int)freq);
 210
 211     if (playing_note) {
 212         if (!audio_initialized) {
 213             audio_init();
 214         }
 215         for (int i = 7; i >= 0; i--) {
 216             if (frequencies[i] == freq) {
 217                 frequencies[i] = 0;
 218                 volumes[i] = 0;
 219                 for (int j = i; (j < 7); j++) {
 220                     frequencies[j] = frequencies[j+1];
 221                     frequencies[j+1] = 0;
 222                     volumes[j] = volumes[j+1];
 223                     volumes[j+1] = 0;
 224                 }
 225                 break;
 226             }
 227         }
 228         voices--;
 229         if (voices < 0)
 230             voices = 0;
 231         if (voice_place >= voices) {
 232             voice_place = 0;
 233         }
 234         if (voices == 0) {
 235             #ifdef C6_AUDIO
 236                 DISABLE_AUDIO_COUNTER_3_ISR;
 237                 DISABLE_AUDIO_COUNTER_3_OUTPUT;
 238             #endif
 239             #ifdef B5_AUDIO
 240                 DISABLE_AUDIO_COUNTER_1_ISR;
 241                 DISABLE_AUDIO_COUNTER_1_OUTPUT;
 242             #endif
 243             frequency = 0;
 244             frequency_alt = 0;
 245             volume = 0;
 246             playing_note = false;
 247         }
 248     }
 249 }
 250
 251 #ifdef VIBRATO_ENABLE
 252
 253 float mod(float a, int b)
 254 {
 255     float r = fmod(a, b);
 256     return r < 0 ? r + b : r;
 257 }
 258
 259 float vibrato(float average_freq) {
 260     #ifdef VIBRATO_STRENGTH_ENABLE
 261         float vibrated_freq = average_freq * pow(vibrato_lut[(int)vibrato_counter], vibrato_strength);
 262     #else
 263         float vibrated_freq = average_freq * vibrato_lut[(int)vibrato_counter];
 264     #endif
 265     vibrato_counter = mod((vibrato_counter + vibrato_rate * (1.0 + 440.0/average_freq)), VIBRATO_LUT_LENGTH);
 266     return vibrated_freq;
 267 }
 268
 269 #endif
 270
 271 #ifdef C6_AUDIO
 272 ISR(TIMER3_COMPA_vect)
 273 {
 274     float freq;
 275
 276     if (playing_note) {
 277         if (voices > 0) {
 278
 279             #ifdef B5_AUDIO
 280             float freq_alt = 0;
 281                 if (voices > 1) {
 282                     if (polyphony_rate == 0) {
 283                         if (glissando) {
 284                             if (frequency_alt != 0 && frequency_alt < frequencies[voices - 2] && frequency_alt < frequencies[voices - 2] * pow(2, -440/frequencies[voices - 2]/12/2)) {
 285                                 frequency_alt = frequency_alt * pow(2, 440/frequency_alt/12/2);
 286                             } else if (frequency_alt != 0 && frequency_alt > frequencies[voices - 2] && frequency_alt > frequencies[voices - 2] * pow(2, 440/frequencies[voices - 2]/12/2)) {
 287                                 frequency_alt = frequency_alt * pow(2, -440/frequency_alt/12/2);
 288                             } else {
 289                                 frequency_alt = frequencies[voices - 2];
 290                             }
 291                         } else {
 292                             frequency_alt = frequencies[voices - 2];
 293                         }
 294
 295                         #ifdef VIBRATO_ENABLE
 296                             if (vibrato_strength > 0) {
 297                                 freq_alt = vibrato(frequency_alt);
 298                             } else {
 299                                 freq_alt = frequency_alt;
 300                             }
 301                         #else
 302                             freq_alt = frequency_alt;
 303                         #endif
 304                     }
 305
 306                     if (envelope_index < 65535) {
 307                         envelope_index++;
 308                     }
 309
 310                     freq_alt = voice_envelope(freq_alt);
 311
 312                     if (freq_alt < 30.517578125) {
 313                         freq_alt = 30.52;
 314                     }
 315
 316                     TIMER_1_PERIOD = (uint16_t)(((float)F_CPU) / (freq_alt * CPU_PRESCALER));
 317                     TIMER_1_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq_alt * CPU_PRESCALER)) * note_timbre);
 318                 }
 319             #endif
 320
 321             if (polyphony_rate > 0) {
 322                 if (voices > 1) {
 323                     voice_place %= voices;
 324                     if (place++ > (frequencies[voice_place] / polyphony_rate / CPU_PRESCALER)) {
 325                         voice_place = (voice_place + 1) % voices;
 326                         place = 0.0;
 327                     }
 328                 }
 329
 330                 #ifdef VIBRATO_ENABLE
 331                     if (vibrato_strength > 0) {
 332                         freq = vibrato(frequencies[voice_place]);
 333                     } else {
 334                         freq = frequencies[voice_place];
 335                     }
 336                 #else
 337                     freq = frequencies[voice_place];
 338                 #endif
 339             } else {
 340                 if (glissando) {
 341                     if (frequency != 0 && frequency < frequencies[voices - 1] && frequency < frequencies[voices - 1] * pow(2, -440/frequencies[voices - 1]/12/2)) {
 342                         frequency = frequency * pow(2, 440/frequency/12/2);
 343                     } else if (frequency != 0 && frequency > frequencies[voices - 1] && frequency > frequencies[voices - 1] * pow(2, 440/frequencies[voices - 1]/12/2)) {
 344                         frequency = frequency * pow(2, -440/frequency/12/2);
 345                     } else {
 346                         frequency = frequencies[voices - 1];
 347                     }
 348                 } else {
 349                     frequency = frequencies[voices - 1];
 350                 }
 351
 352                 #ifdef VIBRATO_ENABLE
 353                     if (vibrato_strength > 0) {
 354                         freq = vibrato(frequency);
 355                     } else {
 356                         freq = frequency;
 357                     }
 358                 #else
 359                     freq = frequency;
 360                 #endif
 361             }
 362
 363             if (envelope_index < 65535) {
 364                 envelope_index++;
 365             }
 366
 367             freq = voice_envelope(freq);
 368
 369             if (freq < 30.517578125) {
 370                 freq = 30.52;
 371             }
 372
 373             TIMER_3_PERIOD = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
 374             TIMER_3_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);
 375         }
 376     }
 377
 378     if (playing_notes) {
 379         if (note_frequency > 0) {
 380             #ifdef VIBRATO_ENABLE
 381                 if (vibrato_strength > 0) {
 382                     freq = vibrato(note_frequency);
 383                 } else {
 384                     freq = note_frequency;
 385                 }
 386             #else
 387                     freq = note_frequency;
 388             #endif
 389
 390             if (envelope_index < 65535) {
 391                 envelope_index++;
 392             }
 393             freq = voice_envelope(freq);
 394
 395             TIMER_3_PERIOD = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
 396             TIMER_3_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);
 397         } else {
 398             TIMER_3_PERIOD = 0;
 399             TIMER_3_DUTY_CYCLE = 0;
 400         }
 401
 402         note_position++;
 403         bool end_of_note = false;
 404         if (TIMER_3_PERIOD > 0) {
 405             end_of_note = (note_position >= (note_length / TIMER_3_PERIOD * 0xFFFF));
 406         } else {
 407             end_of_note = (note_position >= (note_length * 0x7FF));
 408         }
 409
 410         if (end_of_note) {
 411             current_note++;
 412             if (current_note >= notes_count) {
 413                 if (notes_repeat) {
 414                     current_note = 0;
 415                 } else {
 416                     DISABLE_AUDIO_COUNTER_3_ISR;
 417                     DISABLE_AUDIO_COUNTER_3_OUTPUT;
 418                     playing_notes = false;
 419                     return;
 420                 }
 421             }
 422             if (!note_resting && (notes_rest > 0)) {
 423                 note_resting = true;
 424                 note_frequency = 0;
 425                 note_length = notes_rest;
 426                 current_note--;
 427             } else {
 428                 note_resting = false;
 429                 envelope_index = 0;
 430                 note_frequency = (*notes_pointer)[current_note][0];
 431                 note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
 432             }
 433
 434             note_position = 0;
 435         }
 436     }
 437
 438     if (!audio_config.enable) {
 439         playing_notes = false;
 440         playing_note = false;
 441     }
 442 }
 443 #endif
 444
 445 #ifdef B5_AUDIO
 446 ISR(TIMER1_COMPA_vect)
 447 {
 448     #if defined(B5_AUDIO) && !defined(C6_AUDIO)
 449     float freq = 0;
 450
 451     if (playing_note) {
 452         if (voices > 0) {
 453             if (polyphony_rate > 0) {
 454                 if (voices > 1) {
 455                     voice_place %= voices;
 456                     if (place++ > (frequencies[voice_place] / polyphony_rate / CPU_PRESCALER)) {
 457                         voice_place = (voice_place + 1) % voices;
 458                         place = 0.0;
 459                     }
 460                 }
 461
 462                 #ifdef VIBRATO_ENABLE
 463                     if (vibrato_strength > 0) {
 464                         freq = vibrato(frequencies[voice_place]);
 465                     } else {
 466                         freq = frequencies[voice_place];
 467                     }
 468                 #else
 469                     freq = frequencies[voice_place];
 470                 #endif
 471             } else {
 472                 if (glissando) {
 473                     if (frequency != 0 && frequency < frequencies[voices - 1] && frequency < frequencies[voices - 1] * pow(2, -440/frequencies[voices - 1]/12/2)) {
 474                         frequency = frequency * pow(2, 440/frequency/12/2);
 475                     } else if (frequency != 0 && frequency > frequencies[voices - 1] && frequency > frequencies[voices - 1] * pow(2, 440/frequencies[voices - 1]/12/2)) {
 476                         frequency = frequency * pow(2, -440/frequency/12/2);
 477                     } else {
 478                         frequency = frequencies[voices - 1];
 479                     }
 480                 } else {
 481                     frequency = frequencies[voices - 1];
 482                 }
 483
 484                 #ifdef VIBRATO_ENABLE
 485                     if (vibrato_strength > 0) {
 486                         freq = vibrato(frequency);
 487                     } else {
 488                         freq = frequency;
 489                     }
 490                 #else
 491                     freq = frequency;
 492                 #endif
 493             }
 494
 495             if (envelope_index < 65535) {
 496                 envelope_index++;
 497             }
 498
 499             freq = voice_envelope(freq);
 500
 501             if (freq < 30.517578125) {
 502                 freq = 30.52;
 503             }
 504
 505             TIMER_1_PERIOD = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
 506             TIMER_1_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);
 507         }
 508     }
 509
 510     if (playing_notes) {
 511         if (note_frequency > 0) {
 512             #ifdef VIBRATO_ENABLE
 513                 if (vibrato_strength > 0) {
 514                     freq = vibrato(note_frequency);
 515                 } else {
 516                     freq = note_frequency;
 517                 }
 518             #else
 519                     freq = note_frequency;
 520             #endif
 521
 522             if (envelope_index < 65535) {
 523                 envelope_index++;
 524             }
 525             freq = voice_envelope(freq);
 526
 527             TIMER_1_PERIOD = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
 528             TIMER_1_DUTY_CYCLE = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);
 529         } else {
 530             TIMER_1_PERIOD = 0;
 531             TIMER_1_DUTY_CYCLE = 0;
 532         }
 533
 534         note_position++;
 535         bool end_of_note = false;
 536         if (TIMER_1_PERIOD > 0) {
 537             end_of_note = (note_position >= (note_length / TIMER_1_PERIOD * 0xFFFF));
 538         } else {
 539             end_of_note = (note_position >= (note_length * 0x7FF));
 540         }
 541
 542         if (end_of_note) {
 543             current_note++;
 544             if (current_note >= notes_count) {
 545                 if (notes_repeat) {
 546                     current_note = 0;
 547                 } else {
 548                     DISABLE_AUDIO_COUNTER_1_ISR;
 549                     DISABLE_AUDIO_COUNTER_1_OUTPUT;
 550                     playing_notes = false;
 551                     return;
 552                 }
 553             }
 554             if (!note_resting && (notes_rest > 0)) {
 555                 note_resting = true;
 556                 note_frequency = 0;
 557                 note_length = notes_rest;
 558                 current_note--;
 559             } else {
 560                 note_resting = false;
 561                 envelope_index = 0;
 562                 note_frequency = (*notes_pointer)[current_note][0];
 563                 note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
 564             }
 565
 566             note_position = 0;
 567         }
 568     }
 569
 570     if (!audio_config.enable) {
 571         playing_notes = false;
 572         playing_note = false;
 573     }
 574 #endif
 575 }
 576 #endif
 577
 578 void play_note(float freq, int vol) {
 579
 580     dprintf("audio play note freq=%d vol=%d", (int)freq, vol);
 581
 582     if (!audio_initialized) {
 583         audio_init();
 584     }
 585
 586     if (audio_config.enable && voices < 8) {
 587         #ifdef C6_AUDIO
 588             DISABLE_AUDIO_COUNTER_3_ISR;
 589         #endif
 590         #ifdef B5_AUDIO
 591             DISABLE_AUDIO_COUNTER_1_ISR;
 592         #endif
 593
 594         // Cancel notes if notes are playing
 595         if (playing_notes)
 596             stop_all_notes();
 597
 598         playing_note = true;
 599
 600         envelope_index = 0;
 601
 602         if (freq > 0) {
 603             frequencies[voices] = freq;
 604             volumes[voices] = vol;
 605             voices++;
 606         }
 607
 608         #ifdef C6_AUDIO
 609             ENABLE_AUDIO_COUNTER_3_ISR;
 610             ENABLE_AUDIO_COUNTER_3_OUTPUT;
 611         #endif
 612         #ifdef B5_AUDIO
 613             #ifdef C6_AUDIO
 614             if (voices > 1) {
 615                 ENABLE_AUDIO_COUNTER_1_ISR;
 616                 ENABLE_AUDIO_COUNTER_1_OUTPUT;
 617             }
 618             #else
 619             ENABLE_AUDIO_COUNTER_1_ISR;
 620             ENABLE_AUDIO_COUNTER_1_OUTPUT;
 621             #endif
 622         #endif
 623     }
 624
 625 }
 626
 627 void play_notes(float (*np)[][2], uint16_t n_count, bool n_repeat, float n_rest)
 628 {
 629
 630     if (!audio_initialized) {
 631         audio_init();
 632     }
 633
 634     if (audio_config.enable) {
 635
 636         #ifdef C6_AUDIO
 637             DISABLE_AUDIO_COUNTER_3_ISR;
 638         #endif
 639         #ifdef B5_AUDIO
 640             DISABLE_AUDIO_COUNTER_1_ISR;
 641         #endif
 642
 643         // Cancel note if a note is playing
 644         if (playing_note)
 645             stop_all_notes();
 646
 647         playing_notes = true;
 648
 649         notes_pointer = np;
 650         notes_count = n_count;
 651         notes_repeat = n_repeat;
 652         notes_rest = n_rest;
 653
 654         place = 0;
 655         current_note = 0;
 656
 657         note_frequency = (*notes_pointer)[current_note][0];
 658         note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
 659         note_position = 0;
 660
 661
 662         #ifdef C6_AUDIO
 663             ENABLE_AUDIO_COUNTER_3_ISR;
 664             ENABLE_AUDIO_COUNTER_3_OUTPUT;
 665         #endif
 666         #ifdef B5_AUDIO
 667             #ifndef C6_AUDIO
 668             ENABLE_AUDIO_COUNTER_1_ISR;
 669             ENABLE_AUDIO_COUNTER_1_OUTPUT;
 670             #endif
 671         #endif
 672     }
 673
 674 }
 675
 676 bool is_playing_notes(void) {
 677     return playing_notes;
 678 }
 679
 680 bool is_audio_on(void) {
 681     return (audio_config.enable != 0);
 682 }
 683
 684 void audio_toggle(void) {
 685     audio_config.enable ^= 1;
 686     eeconfig_update_audio(audio_config.raw);
 687     if (audio_config.enable)
 688         audio_on_user();
 689 }
 690
 691 void audio_on(void) {
 692     audio_config.enable = 1;
 693     eeconfig_update_audio(audio_config.raw);
 694     audio_on_user();
 695 }
 696
 697 void audio_off(void) {
 698     audio_config.enable = 0;
 699     eeconfig_update_audio(audio_config.raw);
 700 }
 701
 702 #ifdef VIBRATO_ENABLE
 703
 704 // Vibrato rate functions
 705
 706 void set_vibrato_rate(float rate) {
 707     vibrato_rate = rate;
 708 }
 709
 710 void increase_vibrato_rate(float change) {
 711     vibrato_rate *= change;
 712 }
 713
 714 void decrease_vibrato_rate(float change) {
 715     vibrato_rate /= change;
 716 }
 717
 718 #ifdef VIBRATO_STRENGTH_ENABLE
 719
 720 void set_vibrato_strength(float strength) {
 721     vibrato_strength = strength;
 722 }
 723
 724 void increase_vibrato_strength(float change) {
 725     vibrato_strength *= change;
 726 }
 727
 728 void decrease_vibrato_strength(float change) {
 729     vibrato_strength /= change;
 730 }
 731
 732 #endif  /* VIBRATO_STRENGTH_ENABLE */
 733
 734 #endif /* VIBRATO_ENABLE */
 735
 736 // Polyphony functions
 737
 738 void set_polyphony_rate(float rate) {
 739     polyphony_rate = rate;
 740 }
 741
 742 void enable_polyphony() {
 743     polyphony_rate = 5;
 744 }
 745
 746 void disable_polyphony() {
 747     polyphony_rate = 0;
 748 }
 749
 750 void increase_polyphony_rate(float change) {
 751     polyphony_rate *= change;
 752 }
 753
 754 void decrease_polyphony_rate(float change) {
 755     polyphony_rate /= change;
 756 }
 757
 758 // Timbre function
 759
 760 void set_timbre(float timbre) {
 761     note_timbre = timbre;
 762 }
 763
 764 // Tempo functions
 765
 766 void set_tempo(uint8_t tempo) {
 767     note_tempo = tempo;
 768 }
 769
 770 void decrease_tempo(uint8_t tempo_change) {
 771     note_tempo += tempo_change;
 772 }
 773
 774 void increase_tempo(uint8_t tempo_change) {
 775     if (note_tempo - tempo_change < 10) {
 776         note_tempo = 10;
 777     } else {
 778         note_tempo -= tempo_change;
 779     }
 780 }