/* 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 .
*/
#include "audio.h"
#include "ch.h"
#include "hal.h"
#include
#include "print.h"
#include "keymap.h"
#include "eeconfig.h"
// -----------------------------------------------------------------------------
int voices = 0;
int voice_place = 0;
float frequency = 0;
float frequency_alt = 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;
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;
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;
bool glissando = true;
#ifndef STARTUP_SONG
# define STARTUP_SONG SONG(STARTUP_SOUND)
#endif
float startup_song[][2] = STARTUP_SONG;
static void gpt_cb8(GPTDriver *gptp);
#define DAC_BUFFER_SIZE 100
#ifndef DAC_SAMPLE_MAX
# define DAC_SAMPLE_MAX 65535U
#endif
#define START_CHANNEL_1() \
gptStart(&GPTD6, &gpt6cfg1); \
gptStartContinuous(&GPTD6, 2U)
#define START_CHANNEL_2() \
gptStart(&GPTD7, &gpt7cfg1); \
gptStartContinuous(&GPTD7, 2U)
#define STOP_CHANNEL_1() gptStopTimer(&GPTD6)
#define STOP_CHANNEL_2() gptStopTimer(&GPTD7)
#define RESTART_CHANNEL_1() \
STOP_CHANNEL_1(); \
START_CHANNEL_1()
#define RESTART_CHANNEL_2() \
STOP_CHANNEL_2(); \
START_CHANNEL_2()
#define UPDATE_CHANNEL_1_FREQ(freq) \
gpt6cfg1.frequency = freq * DAC_BUFFER_SIZE; \
RESTART_CHANNEL_1()
#define UPDATE_CHANNEL_2_FREQ(freq) \
gpt7cfg1.frequency = freq * DAC_BUFFER_SIZE; \
RESTART_CHANNEL_2()
#define GET_CHANNEL_1_FREQ (uint16_t)(gpt6cfg1.frequency * DAC_BUFFER_SIZE)
#define GET_CHANNEL_2_FREQ (uint16_t)(gpt7cfg1.frequency * DAC_BUFFER_SIZE)
/*
* GPT6 configuration.
*/
// static const GPTConfig gpt6cfg1 = {
// .frequency = 1000000U,
// .callback = NULL,
// .cr2 = TIM_CR2_MMS_1, /* MMS = 010 = TRGO on Update Event. */
// .dier = 0U
// };
GPTConfig gpt6cfg1 = {.frequency = 440U * DAC_BUFFER_SIZE,
.callback = NULL,
.cr2 = TIM_CR2_MMS_1, /* MMS = 010 = TRGO on Update Event. */
.dier = 0U};
GPTConfig gpt7cfg1 = {.frequency = 440U * DAC_BUFFER_SIZE,
.callback = NULL,
.cr2 = TIM_CR2_MMS_1, /* MMS = 010 = TRGO on Update Event. */
.dier = 0U};
GPTConfig gpt8cfg1 = {.frequency = 10,
.callback = gpt_cb8,
.cr2 = TIM_CR2_MMS_1, /* MMS = 010 = TRGO on Update Event. */
.dier = 0U};
/*
* DAC test buffer (sine wave).
*/
// static const dacsample_t dac_buffer[DAC_BUFFER_SIZE] = {
// 2047, 2082, 2118, 2154, 2189, 2225, 2260, 2296, 2331, 2367, 2402, 2437,
// 2472, 2507, 2542, 2576, 2611, 2645, 2679, 2713, 2747, 2780, 2813, 2846,
// 2879, 2912, 2944, 2976, 3008, 3039, 3070, 3101, 3131, 3161, 3191, 3221,
// 3250, 3278, 3307, 3335, 3362, 3389, 3416, 3443, 3468, 3494, 3519, 3544,
// 3568, 3591, 3615, 3637, 3660, 3681, 3703, 3723, 3744, 3763, 3782, 3801,
// 3819, 3837, 3854, 3870, 3886, 3902, 3917, 3931, 3944, 3958, 3970, 3982,
// 3993, 4004, 4014, 4024, 4033, 4041, 4049, 4056, 4062, 4068, 4074, 4078,
// 4082, 4086, 4089, 4091, 4092, 4093, 4094, 4093, 4092, 4091, 4089, 4086,
// 4082, 4078, 4074, 4068, 4062, 4056, 4049, 4041, 4033, 4024, 4014, 4004,
// 3993, 3982, 3970, 3958, 3944, 3931, 3917, 3902, 3886, 3870, 3854, 3837,
// 3819, 3801, 3782, 3763, 3744, 3723, 3703, 3681, 3660, 3637, 3615, 3591,
// 3568, 3544, 3519, 3494, 3468, 3443, 3416, 3389, 3362, 3335, 3307, 3278,
// 3250, 3221, 3191, 3161, 3131, 3101, 3070, 3039, 3008, 2976, 2944, 2912,
// 2879, 2846, 2813, 2780, 2747, 2713, 2679, 2645, 2611, 2576, 2542, 2507,
// 2472, 2437, 2402, 2367, 2331, 2296, 2260, 2225, 2189, 2154, 2118, 2082,
// 2047, 2012, 1976, 1940, 1905, 1869, 1834, 1798, 1763, 1727, 1692, 1657,
// 1622, 1587, 1552, 1518, 1483, 1449, 1415, 1381, 1347, 1314, 1281, 1248,
// 1215, 1182, 1150, 1118, 1086, 1055, 1024, 993, 963, 933, 903, 873,
// 844, 816, 787, 759, 732, 705, 678, 651, 626, 600, 575, 550,
// 526, 503, 479, 457, 434, 413, 391, 371, 350, 331, 312, 293,
// 275, 257, 240, 224, 208, 192, 177, 163, 150, 136, 124, 112,
// 101, 90, 80, 70, 61, 53, 45, 38, 32, 26, 20, 16,
// 12, 8, 5, 3, 2, 1, 0, 1, 2, 3, 5, 8,
// 12, 16, 20, 26, 32, 38, 45, 53, 61, 70, 80, 90,
// 101, 112, 124, 136, 150, 163, 177, 192, 208, 224, 240, 257,
// 275, 293, 312, 331, 350, 371, 391, 413, 434, 457, 479, 503,
// 526, 550, 575, 600, 626, 651, 678, 705, 732, 759, 787, 816,
// 844, 873, 903, 933, 963, 993, 1024, 1055, 1086, 1118, 1150, 1182,
// 1215, 1248, 1281, 1314, 1347, 1381, 1415, 1449, 1483, 1518, 1552, 1587,
// 1622, 1657, 1692, 1727, 1763, 1798, 1834, 1869, 1905, 1940, 1976, 2012
// };
// static const dacsample_t dac_buffer_2[DAC_BUFFER_SIZE] = {
// 12, 8, 5, 3, 2, 1, 0, 1, 2, 3, 5, 8,
// 12, 16, 20, 26, 32, 38, 45, 53, 61, 70, 80, 90,
// 101, 112, 124, 136, 150, 163, 177, 192, 208, 224, 240, 257,
// 275, 293, 312, 331, 350, 371, 391, 413, 434, 457, 479, 503,
// 526, 550, 575, 600, 626, 651, 678, 705, 732, 759, 787, 816,
// 844, 873, 903, 933, 963, 993, 1024, 1055, 1086, 1118, 1150, 1182,
// 1215, 1248, 1281, 1314, 1347, 1381, 1415, 1449, 1483, 1518, 1552, 1587,
// 1622, 1657, 1692, 1727, 1763, 1798, 1834, 1869, 1905, 1940, 1976, 2012,
// 2047, 2082, 2118, 2154, 2189, 2225, 2260, 2296, 2331, 2367, 2402, 2437,
// 2472, 2507, 2542, 2576, 2611, 2645, 2679, 2713, 2747, 2780, 2813, 2846,
// 2879, 2912, 2944, 2976, 3008, 3039, 3070, 3101, 3131, 3161, 3191, 3221,
// 3250, 3278, 3307, 3335, 3362, 3389, 3416, 3443, 3468, 3494, 3519, 3544,
// 3568, 3591, 3615, 3637, 3660, 3681, 3703, 3723, 3744, 3763, 3782, 3801,
// 3819, 3837, 3854, 3870, 3886, 3902, 3917, 3931, 3944, 3958, 3970, 3982,
// 3993, 4004, 4014, 4024, 4033, 4041, 4049, 4056, 4062, 4068, 4074, 4078,
// 4082, 4086, 4089, 4091, 4092, 4093, 4094, 4093, 4092, 4091, 4089, 4086,
// 4082, 4078, 4074, 4068, 4062, 4056, 4049, 4041, 4033, 4024, 4014, 4004,
// 3993, 3982, 3970, 3958, 3944, 3931, 3917, 3902, 3886, 3870, 3854, 3837,
// 3819, 3801, 3782, 3763, 3744, 3723, 3703, 3681, 3660, 3637, 3615, 3591,
// 3568, 3544, 3519, 3494, 3468, 3443, 3416, 3389, 3362, 3335, 3307, 3278,
// 3250, 3221, 3191, 3161, 3131, 3101, 3070, 3039, 3008, 2976, 2944, 2912,
// 2879, 2846, 2813, 2780, 2747, 2713, 2679, 2645, 2611, 2576, 2542, 2507,
// 2472, 2437, 2402, 2367, 2331, 2296, 2260, 2225, 2189, 2154, 2118, 2082,
// 2047, 2012, 1976, 1940, 1905, 1869, 1834, 1798, 1763, 1727, 1692, 1657,
// 1622, 1587, 1552, 1518, 1483, 1449, 1415, 1381, 1347, 1314, 1281, 1248,
// 1215, 1182, 1150, 1118, 1086, 1055, 1024, 993, 963, 933, 903, 873,
// 844, 816, 787, 759, 732, 705, 678, 651, 626, 600, 575, 550,
// 526, 503, 479, 457, 434, 413, 391, 371, 350, 331, 312, 293,
// 275, 257, 240, 224, 208, 192, 177, 163, 150, 136, 124, 112,
// 101, 90, 80, 70, 61, 53, 45, 38, 32, 26, 20, 16
// };
// squarewave
static const dacsample_t dac_buffer[DAC_BUFFER_SIZE] = {
// First half is max, second half is 0
[0 ... DAC_BUFFER_SIZE / 2 - 1] = DAC_SAMPLE_MAX,
[DAC_BUFFER_SIZE / 2 ... DAC_BUFFER_SIZE - 1] = 0,
};
// squarewave
static const dacsample_t dac_buffer_2[DAC_BUFFER_SIZE] = {
// opposite of dac_buffer above
[0 ... DAC_BUFFER_SIZE / 2 - 1] = 0,
[DAC_BUFFER_SIZE / 2 ... DAC_BUFFER_SIZE - 1] = DAC_SAMPLE_MAX,
};
/*
* DAC streaming callback.
*/
size_t nz = 0;
static void end_cb1(DACDriver *dacp) {
(void)dacp;
nz++;
if ((nz % 1000) == 0) {
// palTogglePad(GPIOD, GPIOD_LED3);
}
}
/*
* DAC error callback.
*/
static void error_cb1(DACDriver *dacp, dacerror_t err) {
(void)dacp;
(void)err;
chSysHalt("DAC failure");
}
static const DACConfig dac1cfg1 = {.init = DAC_SAMPLE_MAX, .datamode = DAC_DHRM_12BIT_RIGHT};
static const DACConversionGroup dacgrpcfg1 = {.num_channels = 1U, .end_cb = end_cb1, .error_cb = error_cb1, .trigger = DAC_TRG(0)};
static const DACConfig dac1cfg2 = {.init = DAC_SAMPLE_MAX, .datamode = DAC_DHRM_12BIT_RIGHT};
static const DACConversionGroup dacgrpcfg2 = {.num_channels = 1U, .end_cb = end_cb1, .error_cb = error_cb1, .trigger = DAC_TRG(0)};
void audio_init() {
if (audio_initialized) {
return;
}
// Check EEPROM
#ifdef EEPROM_ENABLE
if (!eeconfig_is_enabled()) {
eeconfig_init();
}
audio_config.raw = eeconfig_read_audio();
#else // ARM EEPROM
audio_config.enable = true;
# ifdef AUDIO_CLICKY_ON
audio_config.clicky_enable = true;
# endif
#endif // ARM EEPROM
/*
* Starting DAC1 driver, setting up the output pin as analog as suggested
* by the Reference Manual.
*/
palSetPadMode(GPIOA, 4, PAL_MODE_INPUT_ANALOG);
palSetPadMode(GPIOA, 5, PAL_MODE_INPUT_ANALOG);
dacStart(&DACD1, &dac1cfg1);
dacStart(&DACD2, &dac1cfg2);
/*
* Starting GPT6/7 driver, it is used for triggering the DAC.
*/
START_CHANNEL_1();
START_CHANNEL_2();
/*
* Starting a continuous conversion.
*/
dacStartConversion(&DACD1, &dacgrpcfg1, (dacsample_t *)dac_buffer, DAC_BUFFER_SIZE);
dacStartConversion(&DACD2, &dacgrpcfg2, (dacsample_t *)dac_buffer_2, DAC_BUFFER_SIZE);
audio_initialized = true;
if (audio_config.enable) {
PLAY_SONG(startup_song);
} else {
stop_all_notes();
}
}
void stop_all_notes() {
dprintf("audio stop all notes");
if (!audio_initialized) {
audio_init();
}
voices = 0;
gptStopTimer(&GPTD6);
gptStopTimer(&GPTD7);
gptStopTimer(&GPTD8);
playing_notes = false;
playing_note = false;
frequency = 0;
frequency_alt = 0;
volume = 0;
for (uint8_t i = 0; i < 8; i++) {
frequencies[i] = 0;
volumes[i] = 0;
}
}
void stop_note(float freq) {
dprintf("audio stop note freq=%d", (int)freq);
if (playing_note) {
if (!audio_initialized) {
audio_init();
}
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) {
STOP_CHANNEL_1();
STOP_CHANNEL_2();
gptStopTimer(&GPTD8);
frequency = 0;
frequency_alt = 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
static void gpt_cb8(GPTDriver *gptp) {
float freq;
if (playing_note) {
if (voices > 0) {
float freq_alt = 0;
if (voices > 1) {
if (polyphony_rate == 0) {
if (glissando) {
if (frequency_alt != 0 && frequency_alt < frequencies[voices - 2] && frequency_alt < frequencies[voices - 2] * pow(2, -440 / frequencies[voices - 2] / 12 / 2)) {
frequency_alt = frequency_alt * pow(2, 440 / frequency_alt / 12 / 2);
} else if (frequency_alt != 0 && frequency_alt > frequencies[voices - 2] && frequency_alt > frequencies[voices - 2] * pow(2, 440 / frequencies[voices - 2] / 12 / 2)) {
frequency_alt = frequency_alt * pow(2, -440 / frequency_alt / 12 / 2);
} else {
frequency_alt = frequencies[voices - 2];
}
} else {
frequency_alt = frequencies[voices - 2];
}
#ifdef VIBRATO_ENABLE
if (vibrato_strength > 0) {
freq_alt = vibrato(frequency_alt);
} else {
freq_alt = frequency_alt;
}
#else
freq_alt = frequency_alt;
#endif
}
if (envelope_index < 65535) {
envelope_index++;
}
freq_alt = voice_envelope(freq_alt);
if (freq_alt < 30.517578125) {
freq_alt = 30.52;
}
if (GET_CHANNEL_2_FREQ != (uint16_t)freq_alt) {
UPDATE_CHANNEL_2_FREQ(freq_alt);
} else {
RESTART_CHANNEL_2();
}
// note_timbre;
}
if (polyphony_rate > 0) {
if (voices > 1) {
voice_place %= voices;
if (place++ > (frequencies[voice_place] / polyphony_rate)) {
voice_place = (voice_place + 1) % voices;
place = 0.0;
}
}
#ifdef VIBRATO_ENABLE
if (vibrato_strength > 0) {
freq = vibrato(frequencies[voice_place]);
} else {
freq = frequencies[voice_place];
}
#else
freq = frequencies[voice_place];
#endif
} else {
if (glissando) {
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];
}
} else {
frequency = frequencies[voices - 1];
}
#ifdef VIBRATO_ENABLE
if (vibrato_strength > 0) {
freq = vibrato(frequency);
} else {
freq = frequency;
}
#else
freq = frequency;
#endif
}
if (envelope_index < 65535) {
envelope_index++;
}
freq = voice_envelope(freq);
if (freq < 30.517578125) {
freq = 30.52;
}
if (GET_CHANNEL_1_FREQ != (uint16_t)freq) {
UPDATE_CHANNEL_1_FREQ(freq);
} else {
RESTART_CHANNEL_1();
}
// note_timbre;
}
}
if (playing_notes) {
if (note_frequency > 0) {
#ifdef VIBRATO_ENABLE
if (vibrato_strength > 0) {
freq = vibrato(note_frequency);
} else {
freq = note_frequency;
}
#else
freq = note_frequency;
#endif
if (envelope_index < 65535) {
envelope_index++;
}
freq = voice_envelope(freq);
if (GET_CHANNEL_1_FREQ != (uint16_t)freq) {
UPDATE_CHANNEL_1_FREQ(freq);
UPDATE_CHANNEL_2_FREQ(freq);
}
// note_timbre;
} else {
// gptStopTimer(&GPTD6);
// gptStopTimer(&GPTD7);
}
note_position++;
bool end_of_note = false;
if (GET_CHANNEL_1_FREQ > 0) {
if (!note_resting)
end_of_note = (note_position >= (note_length * 8 - 1));
else
end_of_note = (note_position >= (note_length * 8));
} else {
end_of_note = (note_position >= (note_length * 8));
}
if (end_of_note) {
current_note++;
if (current_note >= notes_count) {
if (notes_repeat) {
current_note = 0;
} else {
STOP_CHANNEL_1();
STOP_CHANNEL_2();
// gptStopTimer(&GPTD8);
playing_notes = false;
return;
}
}
if (!note_resting) {
note_resting = true;
current_note--;
if ((*notes_pointer)[current_note][0] == (*notes_pointer)[current_note + 1][0]) {
note_frequency = 0;
note_length = 1;
} else {
note_frequency = (*notes_pointer)[current_note][0];
note_length = 1;
}
} else {
note_resting = false;
envelope_index = 0;
note_frequency = (*notes_pointer)[current_note][0];
note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
}
note_position = 0;
}
}
if (!audio_config.enable) {
playing_notes = false;
playing_note = false;
}
}
void play_note(float freq, int vol) {
dprintf("audio play note freq=%d vol=%d", (int)freq, vol);
if (!audio_initialized) {
audio_init();
}
if (audio_config.enable && voices < 8) {
// Cancel notes if notes are playing
if (playing_notes) {
stop_all_notes();
}
playing_note = true;
envelope_index = 0;
if (freq > 0) {
frequencies[voices] = freq;
volumes[voices] = vol;
voices++;
}
gptStart(&GPTD8, &gpt8cfg1);
gptStartContinuous(&GPTD8, 2U);
RESTART_CHANNEL_1();
RESTART_CHANNEL_2();
}
}
void play_notes(float (*np)[][2], uint16_t n_count, bool n_repeat) {
if (!audio_initialized) {
audio_init();
}
if (audio_config.enable) {
// 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;
place = 0;
current_note = 0;
note_frequency = (*notes_pointer)[current_note][0];
note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
note_position = 0;
gptStart(&GPTD8, &gpt8cfg1);
gptStartContinuous(&GPTD8, 2U);
RESTART_CHANNEL_1();
RESTART_CHANNEL_2();
}
}
bool is_playing_notes(void) { return playing_notes; }
bool is_audio_on(void) { return (audio_config.enable != 0); }
void audio_toggle(void) {
audio_config.enable ^= 1;
eeconfig_update_audio(audio_config.raw);
if (audio_config.enable) {
audio_on_user();
}
}
void audio_on(void) {
audio_config.enable = 1;
eeconfig_update_audio(audio_config.raw);
audio_on_user();
}
void audio_off(void) {
stop_all_notes();
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;
}
}