/* 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; systime_t last_note_played_at; 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; bool dac_on = true; 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); static bool should_shutoff_dac(void); static void shutoff_dac(void); #define DAC_BUFFER_SIZE 100 #ifndef DAC_SAMPLE_MAX #define DAC_SAMPLE_MAX 65535U #endif #define START_CHANNEL_1() dacStart(&DACD1, &dac1cfg1); \ dacStart(&DACD2, &dac1cfg2); \ dacStartConversion(&DACD1, &dacgrpcfg1, (dacsample_t *)dac_buffer, DAC_BUFFER_SIZE); \ dacStartConversion(&DACD2, &dacgrpcfg2, (dacsample_t *)dac_buffer_2, DAC_BUFFER_SIZE); \ dac_on = true; \ gptStart(&GPTD6, &gpt6cfg1); \ gptStartContinuous(&GPTD6, 2U); \ palSetPadMode(GPIOA, 5, PAL_MODE_INPUT_ANALOG); #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 nx = 0, ny = 0, nz = 0; static void end_cb1(DACDriver *dacp, dacsample_t *buffer, size_t n) { (void)dacp; nz++; if (dac_buffer == buffer) { nx += n; } else { ny += n; } 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 #if defined(STM32_EEPROM_ENABLE) || defined(PROTOCOL_ARM_ATSAM) || defined(EEPROM_SIZE) 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); palSetPad(GPIOA, 5); 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) { last_note_played_at = chVTGetSystemTime(); 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) { last_note_played_at = chVTGetSystemTime(); 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; } if(should_shutoff_dac()) { shutoff_dac(); } } bool should_shutoff_dac() { return ST2MS(chVTTimeElapsedSinceX(last_note_played_at)) > 5 && dac_on; } void shutoff_dac() { dacStopConversion(&DACD2); dacStop(&DACD2); palSetPadMode(GPIOA, 5, PAL_MODE_OUTPUT_PUSHPULL ); palSetPad(GPIOA, 5); dac_on = 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; } }