qmk-firmware/quantum/audio/audio_pwm.c

/* Copyright 2016 Jack Humbert
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <stdio.h>
#include <string.h>
//#include <math.h>
#include <avr/pgmspace.h>
#include <avr/interrupt.h>
#include <avr/io.h>
#include "print.h"
#include "audio.h"
#include "keymap.h"

#include "eeconfig.h"

#define PI 3.14159265

#define CPU_PRESCALER 8

// Timer Abstractions

// TIMSK3 - Timer/Counter #3 Interrupt Mask Register
// Turn on/off 3A interputs, stopping/enabling the ISR calls
#define ENABLE_AUDIO_COUNTER_3_ISR TIMSK3 |= _BV(OCIE3A)
#define DISABLE_AUDIO_COUNTER_3_ISR TIMSK3 &= ~_BV(OCIE3A)

// TCCR3A: Timer/Counter #3 Control Register
// Compare Output Mode (COM3An) = 0b00 = Normal port operation, OC3A disconnected from PC6
#define ENABLE_AUDIO_COUNTER_3_OUTPUT TCCR3A |= _BV(COM3A1);
#define DISABLE_AUDIO_COUNTER_3_OUTPUT TCCR3A &= ~(_BV(COM3A1) | _BV(COM3A0));

#define NOTE_PERIOD ICR3
#define NOTE_DUTY_CYCLE OCR3A

#ifdef PWM_AUDIO
#    include "wave.h"
#    define SAMPLE_DIVIDER 39
#    define SAMPLE_RATE (2000000.0 / SAMPLE_DIVIDER / 2048)
// Resistor value of 1/ (2 * PI * 10nF * (2000000 hertz / SAMPLE_DIVIDER / 10)) for 10nF cap

float    places[8] = {0, 0, 0, 0, 0, 0, 0, 0};
uint16_t place_int = 0;
bool     repeat    = true;
#endif

void delay_us(int count) {
    while (count--) {
        _delay_us(1);
    }
}

int   voices      = 0;
int   voice_place = 0;
float frequency   = 0;
int   volume      = 0;
long  position    = 0;

float frequencies[8] = {0, 0, 0, 0, 0, 0, 0, 0};
int   volumes[8]     = {0, 0, 0, 0, 0, 0, 0, 0};
bool  sliding        = false;

float place = 0;

uint8_t* sample;
uint16_t sample_length = 0;
// float freq = 0;

bool     playing_notes  = false;
bool     playing_note   = false;
float    note_frequency = 0;
float    note_length    = 0;
uint8_t  note_tempo     = TEMPO_DEFAULT;
float    note_timbre    = TIMBRE_DEFAULT;
uint16_t note_position  = 0;
float (*notes_pointer)[][2];
uint16_t notes_count;
bool     notes_repeat;
float    notes_rest;
bool     note_resting = false;

uint16_t current_note = 0;
uint8_t  rest_counter = 0;

#ifdef VIBRATO_ENABLE
float vibrato_counter  = 0;
float vibrato_strength = .5;
float vibrato_rate     = 0.125;
#endif

float polyphony_rate = 0;

static bool audio_initialized = false;

audio_config_t audio_config;

uint16_t envelope_index = 0;

void audio_init() {
    // Check EEPROM
    if (!eeconfig_is_enabled()) {
        eeconfig_init();
    }
    audio_config.raw = eeconfig_read_audio();

#ifdef PWM_AUDIO

    PLLFRQ = _BV(PDIV2);
    PLLCSR = _BV(PLLE);
    while (!(PLLCSR & _BV(PLOCK)))
        ;
    PLLFRQ |= _BV(PLLTM0); /* PCK 48MHz */

    /* Init a fast PWM on Timer4 */
    TCCR4A = _BV(COM4A0) | _BV(PWM4A); /* Clear OC4A on Compare Match */
    TCCR4B = _BV(CS40);                /* No prescaling => f = PCK/256 = 187500Hz */
    OCR4A  = 0;

    /* Enable the OC4A output */
    DDRC |= _BV(PORTC6);

    DISABLE_AUDIO_COUNTER_3_ISR;  // Turn off 3A interputs

    TCCR3A = 0x0;                                 // Options not needed
    TCCR3B = _BV(CS31) | _BV(CS30) | _BV(WGM32);  // 64th prescaling and CTC
    OCR3A  = SAMPLE_DIVIDER - 1;                  // Correct count/compare, related to sample playback

#else

    // Set port PC6 (OC3A and /OC4A) as output
    DDRC |= _BV(PORTC6);

    DISABLE_AUDIO_COUNTER_3_ISR;

    // TCCR3A / TCCR3B: Timer/Counter #3 Control Registers
    // Compare Output Mode (COM3An) = 0b00 = Normal port operation, OC3A disconnected from PC6
    // Waveform Generation Mode (WGM3n) = 0b1110 = Fast PWM Mode 14 (Period = ICR3, Duty Cycle = OCR3A)
    // Clock Select (CS3n) = 0b010 = Clock / 8
    TCCR3A = (0 << COM3A1) | (0 << COM3A0) | (1 << WGM31) | (0 << WGM30);
    TCCR3B = (1 << WGM33) | (1 << WGM32) | (0 << CS32) | (1 << CS31) | (0 << CS30);

#endif

    audio_initialized = true;
}

void stop_all_notes() {
    if (!audio_initialized) {
        audio_init();
    }
    voices = 0;
#ifdef PWM_AUDIO
    DISABLE_AUDIO_COUNTER_3_ISR;
#else
    DISABLE_AUDIO_COUNTER_3_ISR;
    DISABLE_AUDIO_COUNTER_3_OUTPUT;
#endif

    playing_notes = false;
    playing_note  = false;
    frequency     = 0;
    volume        = 0;

    for (uint8_t i = 0; i < 8; i++) {
        frequencies[i] = 0;
        volumes[i]     = 0;
    }
}

void stop_note(float freq) {
    if (playing_note) {
        if (!audio_initialized) {
            audio_init();
        }
#ifdef PWM_AUDIO
        freq = freq / SAMPLE_RATE;
#endif
        for (int i = 7; i >= 0; i--) {
            if (frequencies[i] == freq) {
                frequencies[i] = 0;
                volumes[i]     = 0;
                for (int j = i; (j < 7); j++) {
                    frequencies[j]     = frequencies[j + 1];
                    frequencies[j + 1] = 0;
                    volumes[j]         = volumes[j + 1];
                    volumes[j + 1]     = 0;
                }
                break;
            }
        }
        voices--;
        if (voices < 0) voices = 0;
        if (voice_place >= voices) {
            voice_place = 0;
        }
        if (voices == 0) {
#ifdef PWM_AUDIO
            DISABLE_AUDIO_COUNTER_3_ISR;
#else
            DISABLE_AUDIO_COUNTER_3_ISR;
            DISABLE_AUDIO_COUNTER_3_OUTPUT;
#endif
            frequency    = 0;
            volume       = 0;
            playing_note = false;
        }
    }
}

#ifdef VIBRATO_ENABLE

float mod(float a, int b) {
    float r = fmod(a, b);
    return r < 0 ? r + b : r;
}

float vibrato(float average_freq) {
#    ifdef VIBRATO_STRENGTH_ENABLE
    float vibrated_freq = average_freq * pow(vibrato_lut[(int)vibrato_counter], vibrato_strength);
#    else
    float vibrated_freq = average_freq * vibrato_lut[(int)vibrato_counter];
#    endif
    vibrato_counter = mod((vibrato_counter + vibrato_rate * (1.0 + 440.0 / average_freq)), VIBRATO_LUT_LENGTH);
    return vibrated_freq;
}

#endif

ISR(TIMER3_COMPA_vect) {
    if (playing_note) {
#ifdef PWM_AUDIO
        if (voices == 1) {
            // SINE
            OCR4A = pgm_read_byte(&sinewave[(uint16_t)place]) >> 2;

            // SQUARE
            // if (((int)place) >= 1024){
            //     OCR4A = 0xFF >> 2;
            // } else {
            //     OCR4A = 0x00;
            // }

            // SAWTOOTH
            // OCR4A = (int)place / 4;

            // TRIANGLE
            // if (((int)place) >= 1024) {
            //     OCR4A = (int)place / 2;
            // } else {
            //     OCR4A = 2048 - (int)place / 2;
            // }

            place += frequency;

            if (place >= SINE_LENGTH) place -= SINE_LENGTH;

        } else {
            int sum = 0;
            for (int i = 0; i < voices; i++) {
                // SINE
                sum += pgm_read_byte(&sinewave[(uint16_t)places[i]]) >> 2;

                // SQUARE
                // if (((int)places[i]) >= 1024){
                //     sum += 0xFF >> 2;
                // } else {
                //     sum += 0x00;
                // }

                places[i] += frequencies[i];

                if (places[i] >= SINE_LENGTH) places[i] -= SINE_LENGTH;
            }
            OCR4A = sum;
        }
#else
        if (voices > 0) {
            float freq;
            if (polyphony_rate > 0) {
                if (voices > 1) {
                    voice_place %= voices;
                    if (place++ > (frequencies[voice_place] / polyphony_rate / CPU_PRESCALER)) {
                        voice_place = (voice_place + 1) % voices;
                        place       = 0.0;
                    }
                }
#    ifdef VIBRATO_ENABLE
                if (vibrato_strength > 0) {
                    freq = vibrato(frequencies[voice_place]);
                } else {
#    else
                {
#    endif
                    freq = frequencies[voice_place];
                }
            } else {
                if (frequency != 0 && frequency < frequencies[voices - 1] && frequency < frequencies[voices - 1] * pow(2, -440 / frequencies[voices - 1] / 12 / 2)) {
                    frequency = frequency * pow(2, 440 / frequency / 12 / 2);
                } else if (frequency != 0 && frequency > frequencies[voices - 1] && frequency > frequencies[voices - 1] * pow(2, 440 / frequencies[voices - 1] / 12 / 2)) {
                    frequency = frequency * pow(2, -440 / frequency / 12 / 2);
                } else {
                    frequency = frequencies[voices - 1];
                }

#    ifdef VIBRATO_ENABLE
                if (vibrato_strength > 0) {
                    freq = vibrato(frequency);
                } else {
#    else
                {
#    endif
                    freq = frequency;
                }
            }

            if (envelope_index < 65535) {
                envelope_index++;
            }
            freq = voice_envelope(freq);

            if (freq < 30.517578125) freq = 30.52;
            NOTE_PERIOD     = (int)(((double)F_CPU) / (freq * CPU_PRESCALER));                  // Set max to the period
            NOTE_DUTY_CYCLE = (int)((((double)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);  // Set compare to half the period
        }
#endif
    }

    // SAMPLE
    // OCR4A = pgm_read_byte(&sample[(uint16_t)place_int]);

    // place_int++;

    // if (place_int >= sample_length)
    //     if (repeat)
    //         place_int -= sample_length;
    //     else
    //         DISABLE_AUDIO_COUNTER_3_ISR;

    if (playing_notes) {
#ifdef PWM_AUDIO
        OCR4A = pgm_read_byte(&sinewave[(uint16_t)place]) >> 0;

        place += note_frequency;
        if (place >= SINE_LENGTH) place -= SINE_LENGTH;
#else
        if (note_frequency > 0) {
            float freq;

#    ifdef VIBRATO_ENABLE
            if (vibrato_strength > 0) {
                freq = vibrato(note_frequency);
            } else {
#    else
            {
#    endif
                freq = note_frequency;
            }

            if (envelope_index < 65535) {
                envelope_index++;
            }
            freq = voice_envelope(freq);

            NOTE_PERIOD     = (int)(((double)F_CPU) / (freq * CPU_PRESCALER));                  // Set max to the period
            NOTE_DUTY_CYCLE = (int)((((double)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre);  // Set compare to half the period
        } else {
            NOTE_PERIOD     = 0;
            NOTE_DUTY_CYCLE = 0;
        }
#endif

        note_position++;
        bool end_of_note = false;
        if (NOTE_PERIOD > 0)
            end_of_note = (note_position >= (note_length / NOTE_PERIOD * 0xFFFF));
        else
            end_of_note = (note_position >= (note_length * 0x7FF));
        if (end_of_note) {
            current_note++;
            if (current_note >= notes_count) {
                if (notes_repeat) {
                    current_note = 0;
                } else {
#ifdef PWM_AUDIO
                    DISABLE_AUDIO_COUNTER_3_ISR;
#else
                    DISABLE_AUDIO_COUNTER_3_ISR;
                    DISABLE_AUDIO_COUNTER_3_OUTPUT;
#endif
                    playing_notes = false;
                    return;
                }
            }
            if (!note_resting && (notes_rest > 0)) {
                note_resting   = true;
                note_frequency = 0;
                note_length    = notes_rest;
                current_note--;
            } else {
                note_resting = false;
#ifdef PWM_AUDIO
                note_frequency = (*notes_pointer)[current_note][0] / SAMPLE_RATE;
                note_length    = (*notes_pointer)[current_note][1] * (((float)note_tempo) / 100);
#else
                envelope_index = 0;
                note_frequency = (*notes_pointer)[current_note][0];
                note_length    = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
#endif
            }
            note_position = 0;
        }
    }

    if (!audio_config.enable) {
        playing_notes = false;
        playing_note  = false;
    }
}

void play_note(float freq, int vol) {
    if (!audio_initialized) {
        audio_init();
    }

    if (audio_config.enable && voices < 8) {
        DISABLE_AUDIO_COUNTER_3_ISR;

        // Cancel notes if notes are playing
        if (playing_notes) stop_all_notes();

        playing_note = true;

        envelope_index = 0;

#ifdef PWM_AUDIO
        freq = freq / SAMPLE_RATE;
#endif
        if (freq > 0) {
            frequencies[voices] = freq;
            volumes[voices]     = vol;
            voices++;
        }

#ifdef PWM_AUDIO
        ENABLE_AUDIO_COUNTER_3_ISR;
#else
        ENABLE_AUDIO_COUNTER_3_ISR;
        ENABLE_AUDIO_COUNTER_3_OUTPUT;
#endif
    }
}

void play_notes(float (*np)[][2], uint16_t n_count, bool n_repeat, float n_rest) {
    if (!audio_initialized) {
        audio_init();
    }

    if (audio_config.enable) {
        DISABLE_AUDIO_COUNTER_3_ISR;

        // Cancel note if a note is playing
        if (playing_note) stop_all_notes();

        playing_notes = true;

        notes_pointer = np;
        notes_count   = n_count;
        notes_repeat  = n_repeat;
        notes_rest    = n_rest;

        place        = 0;
        current_note = 0;

#ifdef PWM_AUDIO
        note_frequency = (*notes_pointer)[current_note][0] / SAMPLE_RATE;
        note_length    = (*notes_pointer)[current_note][1] * (((float)note_tempo) / 100);
#else
        note_frequency = (*notes_pointer)[current_note][0];
        note_length    = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
#endif
        note_position = 0;

#ifdef PWM_AUDIO
        ENABLE_AUDIO_COUNTER_3_ISR;
#else
        ENABLE_AUDIO_COUNTER_3_ISR;
        ENABLE_AUDIO_COUNTER_3_OUTPUT;
#endif
    }
}

#ifdef PWM_AUDIO
void play_sample(uint8_t* s, uint16_t l, bool r) {
    if (!audio_initialized) {
        audio_init();
    }

    if (audio_config.enable) {
        DISABLE_AUDIO_COUNTER_3_ISR;
        stop_all_notes();
        place_int     = 0;
        sample        = s;
        sample_length = l;
        repeat        = r;

        ENABLE_AUDIO_COUNTER_3_ISR;
    }
}
#endif

void audio_toggle(void) {
    audio_config.enable ^= 1;
    eeconfig_update_audio(audio_config.raw);
}

void audio_on(void) {
    audio_config.enable = 1;
    eeconfig_update_audio(audio_config.raw);
}

void audio_off(void) {
    audio_config.enable = 0;
    eeconfig_update_audio(audio_config.raw);
}

#ifdef VIBRATO_ENABLE

// Vibrato rate functions

void set_vibrato_rate(float rate) { vibrato_rate = rate; }

void increase_vibrato_rate(float change) { vibrato_rate *= change; }

void decrease_vibrato_rate(float change) { vibrato_rate /= change; }

#    ifdef VIBRATO_STRENGTH_ENABLE

void set_vibrato_strength(float strength) { vibrato_strength = strength; }

void increase_vibrato_strength(float change) { vibrato_strength *= change; }

void decrease_vibrato_strength(float change) { vibrato_strength /= change; }

#    endif /* VIBRATO_STRENGTH_ENABLE */

#endif /* VIBRATO_ENABLE */

// Polyphony functions

void set_polyphony_rate(float rate) { polyphony_rate = rate; }

void enable_polyphony() { polyphony_rate = 5; }

void disable_polyphony() { polyphony_rate = 0; }

void increase_polyphony_rate(float change) { polyphony_rate *= change; }

void decrease_polyphony_rate(float change) { polyphony_rate /= change; }

// Timbre function

void set_timbre(float timbre) { note_timbre = timbre; }

// Tempo functions

void set_tempo(uint8_t tempo) { note_tempo = tempo; }

void decrease_tempo(uint8_t tempo_change) { note_tempo += tempo_change; }

void increase_tempo(uint8_t tempo_change) {
    if (note_tempo - tempo_change < 10) {
        note_tempo = 10;
    } else {
        note_tempo -= tempo_change;
    }
}

//------------------------------------------------------------------------------
// Override these functions in your keymap file to play different tunes on
// startup and bootloader jump
__attribute__((weak)) void play_startup_tone() {}

__attribute__((weak)) void play_goodbye_tone() {}
//------------------------------------------------------------------------------