separate engine

speaker_hal.c → tracker_engine/speaker_hal.c

@@ -85,6 +85,8 @@ void tracker_interrupt_deinit() {
     FURI_CRITICAL_ENTER();
     LL_TIM_DeInit(TIM2);
     FURI_CRITICAL_EXIT();
+
+    furi_hal_interrupt_set_isr(FuriHalInterruptIdTIM2, NULL, NULL);
 }
 
 void tracker_debug_init() {
@@ -93,4 +95,8 @@ void tracker_debug_init() {
 
 void tracker_debug_set(bool value) {
     furi_hal_gpio_write(&gpio_ext_pc3, value);
+}
+
+void tracker_debug_deinit() {
+    furi_hal_gpio_init(&gpio_ext_pc3, GpioModeAnalog, GpioPullNo, GpioSpeedLow);
 }

speaker_hal.h → tracker_engine/speaker_hal.h

@@ -14,4 +14,6 @@ void tracker_interrupt_deinit();
 
 void tracker_debug_init();
 
-void tracker_debug_set(bool value);
+void tracker_debug_set(bool value);
+
+void tracker_debug_deinit();

tracker_engine/tracker.c

@@ -0,0 +1,328 @@
+#include "tracker.h"
+#include <stdbool.h>
+#include "speaker_hal.h"
+
+// SongState song_state = {
+//     .tick = 0,
+//     .tick_limit = 2,
+//     .row = 0,
+// };
+
+typedef struct {
+    uint8_t speed;
+    uint8_t depth;
+    int8_t direction;
+    int8_t value;
+} IntegerOscillator;
+
+typedef struct {
+    float frequency;
+    float frequency_target;
+    float pwm;
+    bool play;
+    IntegerOscillator vibrato;
+} ChannelState;
+
+typedef struct {
+    ChannelState* channels;
+    uint8_t tick;
+    uint8_t tick_limit;
+
+    uint8_t pattern_index;
+    uint8_t row_index;
+} SongState;
+
+typedef struct {
+    uint8_t note;
+    uint8_t effect;
+    uint8_t data;
+} UnpackedRow;
+
+struct Tracker {
+    Song* song;
+    bool playing;
+    TrackerMessageCallback callback;
+    void* context;
+    SongState song_state;
+};
+
+static void channels_state_init(ChannelState* channel) {
+    channel->frequency = 0;
+    channel->frequency_target = FREQUENCY_UNSET;
+    channel->pwm = PWM_DEFAULT;
+    channel->play = false;
+    channel->vibrato.speed = 0;
+    channel->vibrato.depth = 0;
+    channel->vibrato.direction = 0;
+    channel->vibrato.value = 0;
+}
+
+static void tracker_song_state_init(Tracker* tracker) {
+    tracker->song_state.tick = 0;
+    tracker->song_state.tick_limit = 2;
+    tracker->song_state.pattern_index = 0;
+    tracker->song_state.row_index = 0;
+
+    if(tracker->song_state.channels != NULL) {
+        free(tracker->song_state.channels);
+    }
+
+    tracker->song_state.channels = malloc(sizeof(ChannelState) * tracker->song->channels_count);
+    for(uint8_t i = 0; i < tracker->song->channels_count; i++) {
+        channels_state_init(&tracker->song_state.channels[i]);
+    }
+}
+
+static uint8_t record_get_note(Row note) {
+    return note & ROW_NOTE_MASK;
+}
+
+static uint8_t record_get_effect(Row note) {
+    return (note >> 6) & ROW_EFFECT_MASK;
+}
+
+static uint8_t record_get_effect_data(Row note) {
+    return (note >> 10) & ROW_EFFECT_DATA_MASK;
+}
+
+#define NOTES_PER_OCT 12
+const float notes_oct[NOTES_PER_OCT] = {
+    130.813f,
+    138.591f,
+    146.832f,
+    155.563f,
+    164.814f,
+    174.614f,
+    184.997f,
+    195.998f,
+    207.652f,
+    220.00f,
+    233.082f,
+    246.942f,
+};
+
+static float note_to_freq(uint8_t note) {
+    if(note == NOTE_NONE) return 0.0f;
+    note = note - NOTE_C2;
+    uint8_t octave = note / NOTES_PER_OCT;
+    uint8_t note_in_oct = note % NOTES_PER_OCT;
+    return notes_oct[note_in_oct] * (1 << octave);
+}
+
+static float frequency_offset_semitones(float frequency, uint8_t semitones) {
+    return frequency * (1.0f + ((1.0f / 12.0f) * semitones));
+}
+
+static float frequency_get_seventh_of_a_semitone(float frequency) {
+    return frequency * ((1.0f / 12.0f) / 7.0f);
+}
+
+UnpackedRow get_current_row(Song* song, SongState* song_state, uint8_t channel) {
+    Pattern* pattern = &song->patterns[song_state->pattern_index];
+    Row row = pattern->channels[channel].rows[song_state->row_index];
+    return (UnpackedRow){
+        .note = record_get_note(row),
+        .effect = record_get_effect(row),
+        .data = record_get_effect_data(row),
+    };
+}
+
+void tracker_interrupt_body(Tracker* tracker) {
+    const uint8_t channel_index = 0;
+    SongState* song_state = &tracker->song_state;
+    ChannelState* channel_state = &song_state->channels[channel_index];
+    Song* song = tracker->song;
+    UnpackedRow row = get_current_row(song, song_state, channel_index);
+
+    // load frequency from note at tick 0
+    if(song_state->tick == 0) {
+        // handle "on first tick" effects
+        if(row.effect == EffectBreakPattern) {
+            // TODO: advance to next pattern
+            song_state->row_index = row.data;
+
+            // reload note and effect
+            row = get_current_row(song, song_state, channel_index);
+        }
+
+        if(row.effect == EffectJumpToPattern) {
+            // TODO: advance to pattern[data]
+
+            // reload note and effect
+            row = get_current_row(song, song_state, channel_index);
+        }
+
+        // no "else", cos previous effects reloads the effect value
+        if(row.effect == EffectSetSpeed) {
+            song_state->tick_limit = row.data;
+        }
+
+        // handle note effects
+        if(row.note == NOTE_OFF) {
+            channel_state->play = false;
+        } else if((row.note > NOTE_NONE) && (row.note < NOTE_OFF)) {
+            channel_state->play = true;
+
+            // reset vibrato
+            channel_state->vibrato.speed = 0;
+            channel_state->vibrato.depth = 0;
+            channel_state->vibrato.value = 0;
+            channel_state->vibrato.direction = 0;
+
+            // reset pwm
+            channel_state->pwm = PWM_DEFAULT;
+
+            if(row.effect == EffectSlideToNote) {
+                channel_state->frequency_target = note_to_freq(row.note);
+            } else {
+                channel_state->frequency = note_to_freq(row.note);
+                channel_state->frequency_target = FREQUENCY_UNSET;
+            }
+        }
+    }
+
+    if(channel_state->play) {
+        float frequency, pwm;
+
+        if((row.effect == EffectSlideUp || row.effect == EffectSlideDown) &&
+           row.data != EFFECT_DATA_NONE) {
+            // apply slide effect
+            channel_state->frequency += (row.effect == EffectSlideUp ? 1 : -1) * row.data;
+        } else if(row.effect == EffectSlideToNote) {
+            // apply slide to note effect, if target frequency is set
+            if(channel_state->frequency_target > 0) {
+                if(channel_state->frequency_target > channel_state->frequency) {
+                    channel_state->frequency += row.data;
+                    if(channel_state->frequency > channel_state->frequency_target) {
+                        channel_state->frequency = channel_state->frequency_target;
+                        channel_state->frequency_target = FREQUENCY_UNSET;
+                    }
+                } else if(channel_state->frequency_target < channel_state->frequency) {
+                    channel_state->frequency -= row.data;
+                    if(channel_state->frequency < channel_state->frequency_target) {
+                        channel_state->frequency = channel_state->frequency_target;
+                        channel_state->frequency_target = FREQUENCY_UNSET;
+                    }
+                }
+            }
+        }
+
+        frequency = channel_state->frequency;
+        pwm = channel_state->pwm;
+
+        // apply arpeggio effect
+        if(row.effect == EffectArpeggio) {
+            if(row.data != EFFECT_DATA_NONE) {
+                if((song_state->tick % 3) == 1) {
+                    uint8_t note_offset = EFFECT_DATA_GET_X(row.data);
+                    frequency = frequency_offset_semitones(frequency, note_offset);
+                } else if((song_state->tick % 3) == 2) {
+                    uint8_t note_offset = EFFECT_DATA_GET_Y(row.data);
+                    frequency = frequency_offset_semitones(frequency, note_offset);
+                }
+            }
+        } else if(row.effect == EffectVibrato) {
+            // apply vibrato effect, data = speed, depth
+            uint8_t vibrato_speed = EFFECT_DATA_GET_X(row.data);
+            uint8_t vibrato_depth = EFFECT_DATA_GET_Y(row.data);
+
+            // update vibrato parameters if speed or depth is non-zero
+            if(vibrato_speed != 0) channel_state->vibrato.speed = vibrato_speed;
+            if(vibrato_depth != 0) channel_state->vibrato.depth = vibrato_depth;
+
+            // update vibrato value
+            channel_state->vibrato.value +=
+                channel_state->vibrato.direction * channel_state->vibrato.speed;
+
+            // change direction if value is at the limit
+            if(channel_state->vibrato.value > channel_state->vibrato.depth) {
+                channel_state->vibrato.direction = -1;
+            } else if(channel_state->vibrato.value < -channel_state->vibrato.depth) {
+                channel_state->vibrato.direction = 1;
+            } else if(channel_state->vibrato.direction == 0) {
+                // set initial direction, if it is not set
+                channel_state->vibrato.direction = 1;
+            }
+
+            frequency +=
+                (frequency_get_seventh_of_a_semitone(frequency) * channel_state->vibrato.value);
+        } else if(row.effect == EffectPWM) {
+            pwm = (pwm - PWM_MIN) / EFFECT_DATA_1_MAX * row.data + PWM_MIN;
+        }
+
+        tracker_speaker_play(frequency, pwm);
+    } else {
+        tracker_speaker_stop();
+    }
+
+    song_state->tick++;
+    if(song_state->tick >= song_state->tick_limit) {
+        song_state->tick = 0;
+
+        // next note
+        song_state->row_index = (song_state->row_index + 1) % PATTERN_SIZE;
+        //TODO: advance to next pattern
+    }
+}
+
+void tracker_interrupt_cb(void* context) {
+    Tracker* tracker = (Tracker*)context;
+    tracker_debug_set(true);
+    tracker_interrupt_body(tracker);
+    tracker_debug_set(false);
+}
+
+/*********************************************************************
+ * Tracker Interface
+ *********************************************************************/
+
+Tracker* tracker_alloc() {
+    Tracker* tracker = malloc(sizeof(Tracker));
+    return tracker;
+}
+
+void tracker_free(Tracker* tracker) {
+    free(tracker);
+}
+
+void tracker_set_message_callback(Tracker* tracker, TrackerMessageCallback callback, void* context) {
+    furi_check(tracker->playing == false);
+    tracker->callback = callback;
+    tracker->context = context;
+}
+
+void tracker_set_song(Tracker* tracker, Song* song) {
+    furi_check(tracker->playing == false);
+    tracker->song = song;
+    tracker_song_state_init(tracker);
+}
+
+void tracker_set_pattern(Tracker* tracker, uint8_t pattern) {
+    furi_check(tracker->playing == false);
+    furi_check(pattern < tracker->song->patterns_count);
+    tracker->song_state.pattern_index = pattern;
+}
+
+void tracker_set_row(Tracker* tracker, uint8_t row) {
+    furi_check(tracker->playing == false);
+    furi_check(row < PATTERN_SIZE);
+    tracker->song_state.row_index = row;
+}
+
+void tracker_start(Tracker* tracker) {
+    furi_check(tracker->song != NULL);
+
+    tracker->playing = true;
+
+    tracker_debug_init();
+    tracker_speaker_init();
+    tracker_interrupt_init(tracker->song->ticks_per_second, tracker_interrupt_cb, tracker);
+}
+
+void tracker_stop(Tracker* tracker) {
+    tracker_interrupt_deinit();
+    tracker_speaker_deinit();
+    tracker_debug_deinit();
+
+    tracker->playing = false;
+}

tracker_engine/tracker.h

@@ -0,0 +1,38 @@
+#pragma once
+#include "tracker_notes.h"
+#include "tracker_song.h"
+
+typedef enum {
+    TrackerPositionChanged,
+    TrackerEndOfSong,
+} TrackerMessageType;
+
+typedef struct {
+    TrackerMessageType type;
+    union tracker_message_data {
+        struct {
+            uint8_t pattern;
+            uint8_t row;
+        } position;
+    } data;
+} TrackerMessage;
+
+typedef void (*TrackerMessageCallback)(TrackerMessage message, void* context);
+
+typedef struct Tracker Tracker;
+
+Tracker* tracker_alloc();
+
+void tracker_free(Tracker* tracker);
+
+void tracker_set_message_callback(Tracker* tracker, TrackerMessageCallback callback, void* context);
+
+void tracker_set_song(Tracker* tracker, Song* song);
+
+void tracker_set_pattern(Tracker* tracker, uint8_t pattern);
+
+void tracker_set_row(Tracker* tracker, uint8_t row);
+
+void tracker_start(Tracker* tracker);
+
+void tracker_stop(Tracker* tracker);

tracker_engine/tracker_notes.h

@@ -0,0 +1,64 @@
+#pragma once
+
+#define NOTE_NONE 0
+#define NOTE_C2 1
+#define NOTE_Cs2 2
+#define NOTE_D2 3
+#define NOTE_Ds2 4
+#define NOTE_E2 5
+#define NOTE_F2 6
+#define NOTE_Fs2 7
+#define NOTE_G2 8
+#define NOTE_Gs2 9
+#define NOTE_A2 10
+#define NOTE_As2 11
+#define NOTE_B2 12
+#define NOTE_C3 13
+#define NOTE_Cs3 14
+#define NOTE_D3 15
+#define NOTE_Ds3 16
+#define NOTE_E3 17
+#define NOTE_F3 18
+#define NOTE_Fs3 19
+#define NOTE_G3 20
+#define NOTE_Gs3 21
+#define NOTE_A3 22
+#define NOTE_As3 23
+#define NOTE_B3 24
+#define NOTE_C4 25
+#define NOTE_Cs4 26
+#define NOTE_D4 27
+#define NOTE_Ds4 28
+#define NOTE_E4 29
+#define NOTE_F4 30
+#define NOTE_Fs4 31
+#define NOTE_G4 32
+#define NOTE_Gs4 33
+#define NOTE_A4 34
+#define NOTE_As4 35
+#define NOTE_B4 36
+#define NOTE_C5 37
+#define NOTE_Cs5 38
+#define NOTE_D5 39
+#define NOTE_Ds5 40
+#define NOTE_E5 41
+#define NOTE_F5 42
+#define NOTE_Fs5 43
+#define NOTE_G5 44
+#define NOTE_Gs5 45
+#define NOTE_A5 46
+#define NOTE_As5 47
+#define NOTE_B5 48
+#define NOTE_C6 49
+#define NOTE_Cs6 50
+#define NOTE_D6 51
+#define NOTE_Ds6 52
+#define NOTE_E6 53
+#define NOTE_F6 54
+#define NOTE_Fs6 55
+#define NOTE_G6 56
+#define NOTE_Gs6 57
+#define NOTE_A6 58
+#define NOTE_As6 59
+#define NOTE_B6 60
+#define NOTE_OFF 63

tracker_engine/tracker_song.h

@@ -0,0 +1,109 @@
+#pragma once
+#include <stdint.h>
+
+/**
+ * @brief Row
+ * 
+ * AH       AL
+ * FEDCBA98 76543210
+ * nnnnnnee eedddddd
+ * -------- --------
+ * nnnnnn            = [0] do nothing, [1..60] note number, [61] note off, [62..63] not used
+ *       ee ee       = [0..F] effect 
+ *            111222 = [0..63] or [0..7, 0..7] effect data 
+ */
+typedef uint16_t Row;
+
+#define ROW_NOTE_MASK 0x3F
+#define ROW_EFFECT_MASK 0x0F
+#define ROW_EFFECT_DATA_MASK 0x3F
+
+typedef enum {
+    // 0xy, x - first semitones offset, y - second semitones offset. 0 - no offset .. 7 - +7 semitones...
+    // Play the arpeggio chord with three notes. The first note is the base note, the second and third are offset by x and y.
+    // Each note plays one tick.
+    EffectArpeggio = 0x00,
+
+    // 1xx, xx - effect speed, 0 - no effect, 1 - slowest, 0x3F - fastest.
+    // Slide the note pitch up by xx Hz every tick.
+    EffectSlideUp = 0x01,
+
+    // 2xx, xx - effect speed, 0 - no effect, 1 - slowest, 0x3F - fastest.
+    // Slide the note pitch down by xx Hz every tick.
+    EffectSlideDown = 0x02,
+
+    // 3xx, xx - effect speed, 0 - no effect, 1 - slowest, 0x3F - fastest.
+    // Slide the already playing note pitch towards another one by xx Hz every tick.
+    // The note value is saved until the note is playing, so you don't have to repeat the note value to continue sliding.
+    EffectSlideToNote = 0x03,
+
+    // 4xy, x - vibrato speed (0..7), y - vibrato depth (0..7).
+    // Vibrato effect. The pitch of the note increases by x Hz each tick to a positive vibrato depth, then decreases to a negative depth.
+    // Value 1 of depth means 1/7 of a semitone (about 14.28 ct), so value 7 means full semitone.
+    // Note will play without vibrato on the first tick at the beginning of the effect.
+    // Vibrato speed and depth are saved until the note is playing, and will be updated only if they are not zero, so you doesn't have to repeat them every tick.
+    EffectVibrato = 0x04,
+
+    // Effect05 = 0x05,
+    // Effect06 = 0x06,
+    // Effect07 = 0x07,
+    // Effect08 = 0x08,
+    // Effect09 = 0x09,
+    // Effect0A = 0x0A,
+
+    // Bxx, xx - pattern number
+    // Jump to the pattern number xx at first tick of current row.
+    // So if you want to jump to the pattern after note 4, you should put this effect on the 5th note.
+    EffectJumpToPattern = 0x0B,
+
+    // Cxx, xx - pwm value
+    // Set the PWM value to xx.
+    EffectPWM = 0x0C,
+
+    // Bxx, xx - row number
+    // Jump to the row xx in next pattern at first tick of current row.
+    // So if you want to jump to the pattern after note 4, you should put this effect on the 5th note.
+    EffectBreakPattern = 0x0D,
+
+    // Effect0E = 0x0E,
+
+    // Fxx, xx - song speed, 0 - 1 tick per note, 1 - 2 ticks per note, 0x3F - 64 ticks per note.
+    // Set the speed of the song in terms of ticks per note.
+    // Will be applied at the first tick of current row.
+    EffectSetSpeed = 0x0F,
+} Effect;
+
+#define EFFECT_DATA_2(x, y) ((x) | ((y) << 3))
+#define EFFECT_DATA_GET_X(data) ((data)&0x07)
+#define EFFECT_DATA_GET_Y(data) (((data) >> 3) & 0x07)
+#define EFFECT_DATA_NONE 0
+#define EFFECT_DATA_1_MAX 0x3F
+#define EFFECT_DATA_2_MAX 0x07
+
+#define FREQUENCY_UNSET -1.0f
+
+#define PWM_MIN 0.01f
+#define PWM_MAX 0.5f
+#define PWM_DEFAULT PWM_MAX
+
+#define PATTERN_SIZE 64
+
+#define ROW_MAKE(note, effect, data) \
+    ((Row)(((note)&0x3F) | (((effect)&0xF) << 6) | (((data)&0x3F) << 10)))
+
+typedef struct {
+    Row rows[PATTERN_SIZE];
+} Channel;
+
+typedef struct {
+    Channel* channels;
+} Pattern;
+
+typedef struct {
+    uint8_t channels_count;
+    uint8_t patterns_count;
+    Pattern* patterns;
+    uint8_t order_list_size;
+    uint8_t* order_list;
+    uint16_t ticks_per_second;
+} Song;

zero_tracker.c

@@ -1,570 +1,216 @@
 #include <furi.h>
-#include "speaker_hal.h"
 #include "zero_tracker.h"
-
-/**
- * @brief Note record
- * 
- * AH       AL
- * FEDCBA98 76543210
- * nnnnnnee eedddddd
- * -------- --------
- * nnnnnn            = [0] do nothing, [1..60] note number, [61] note off, [62..63] not used
- *       ee ee       = [0..F] effect 
- *            111222 = [0..63] or [0..7, 0..7] effect data 
- */
-typedef uint16_t NoteRecord;
-
-#define NOTE_NONE 0
-#define NOTE_C2 1
-#define NOTE_Cs2 2
-#define NOTE_D2 3
-#define NOTE_Ds2 4
-#define NOTE_E2 5
-#define NOTE_F2 6
-#define NOTE_Fs2 7
-#define NOTE_G2 8
-#define NOTE_Gs2 9
-#define NOTE_A2 10
-#define NOTE_As2 11
-#define NOTE_B2 12
-#define NOTE_C3 13
-#define NOTE_Cs3 14
-#define NOTE_D3 15
-#define NOTE_Ds3 16
-#define NOTE_E3 17
-#define NOTE_F3 18
-#define NOTE_Fs3 19
-#define NOTE_G3 20
-#define NOTE_Gs3 21
-#define NOTE_A3 22
-#define NOTE_As3 23
-#define NOTE_B3 24
-#define NOTE_C4 25
-#define NOTE_Cs4 26
-#define NOTE_D4 27
-#define NOTE_Ds4 28
-#define NOTE_E4 29
-#define NOTE_F4 30
-#define NOTE_Fs4 31
-#define NOTE_G4 32
-#define NOTE_Gs4 33
-#define NOTE_A4 34
-#define NOTE_As4 35
-#define NOTE_B4 36
-#define NOTE_C5 37
-#define NOTE_Cs5 38
-#define NOTE_D5 39
-#define NOTE_Ds5 40
-#define NOTE_E5 41
-#define NOTE_F5 42
-#define NOTE_Fs5 43
-#define NOTE_G5 44
-#define NOTE_Gs5 45
-#define NOTE_A5 46
-#define NOTE_As5 47
-#define NOTE_B5 48
-#define NOTE_C6 49
-#define NOTE_Cs6 50
-#define NOTE_D6 51
-#define NOTE_Ds6 52
-#define NOTE_E6 53
-#define NOTE_F6 54
-#define NOTE_Fs6 55
-#define NOTE_G6 56
-#define NOTE_Gs6 57
-#define NOTE_A6 58
-#define NOTE_As6 59
-#define NOTE_B6 60
-#define NOTE_OFF 63
-
-typedef enum {
-    // 0xy, x - first semitones offset, y - second semitones offset. 0 - no offset .. 7 - +7 semitones...
-    // Play the arpeggio chord with three notes. The first note is the base note, the second and third are offset by x and y.
-    // Each note plays one tick.
-    EffectArpeggio = 0x00,
-
-    // 1xx, xx - effect speed, 0 - no effect, 1 - slowest, 0x3F - fastest.
-    // Slide the note pitch up by xx Hz every tick.
-    EffectSlideUp = 0x01,
-
-    // 2xx, xx - effect speed, 0 - no effect, 1 - slowest, 0x3F - fastest.
-    // Slide the note pitch down by xx Hz every tick.
-    EffectSlideDown = 0x02,
-
-    // 3xx, xx - effect speed, 0 - no effect, 1 - slowest, 0x3F - fastest.
-    // Slide the already playing note pitch towards another one by xx Hz every tick.
-    // The note value is saved until the note is playing, so you don't have to repeat the note value to continue sliding.
-    EffectSlideToNote = 0x03,
-
-    // 4xy, x - vibrato speed (0..7), y - vibrato depth (0..7).
-    // Vibrato effect. The pitch of the note increases by x Hz each tick to a positive vibrato depth, then decreases to a negative depth.
-    // Value 1 of depth means 1/7 of a semitone (about 14.28 ct), so value 7 means full semitone.
-    // Note will play without vibrato on the first tick at the beginning of the effect.
-    // Vibrato speed and depth are saved until the note is playing, and will be updated only if they are not zero, so you doesn't have to repeat them every tick.
-    EffectVibrato = 0x04,
-
-    // Bxx, xx - pattern number
-    // Jump to the pattern number xx at first tick of current row.
-    // So if you want to jump to the pattern after note 4, you should put this effect on the 5th note.
-    EffectJumpToPattern = 0x0B,
-
-    // Cxx, xx - pwm value
-    // Set the PWM value to xx.
-    EffectPWM = 0x0C,
-
-    // Bxx, xx - row number
-    // Jump to the row xx in next pattern at first tick of current row.
-    // So if you want to jump to the pattern after note 4, you should put this effect on the 5th note.
-    EffectBreakPattern = 0x0D,
-
-    // Fxx, xx - song speed, 0 - 1 tick per note, 1 - 2 ticks per note, 0x3F - 64 ticks per note.
-    // Set the speed of the song in terms of ticks per note.
-    EffectSetSpeed = 0x0F,
-} Effect;
-
-#define EFFECT_DATA_NONE 0
-
-#define EFFECT_DATA_2(x, y) ((x) | ((y) << 3))
-
-#define EFFECT_DATA_GET_X(data) ((data)&0x07)
-#define EFFECT_DATA_GET_Y(data) (((data) >> 3) & 0x07)
-
-#define EFFECT_DATA_1_MAX 0x3F
-#define EFFECT_DATA_2_MAX 0x07
-
-#define FREQUENCY_UNSET -1.0f
-
-#define PWM_MIN 0.01f
-#define PWM_MAX 0.5f
-#define PWM_DEFAULT 0.5f
-
-uint8_t record_get_note(NoteRecord note) {
-    return note & 0x3F;
-}
-
-uint8_t record_get_effect(NoteRecord note) {
-    return (note >> 6) & 0xF;
-}
-
-uint8_t record_get_effect_data(NoteRecord note) {
-    return (note >> 10) & 0x3F;
-}
-
-#define RECORD_MAKE(note, effect, data) \
-    ((NoteRecord)(((note)&0x3F) | (((effect)&0xF) << 6) | (((data)&0x3F) << 10)))
-
-#define NOTES_PER_OCT 12
-const float notes_oct[NOTES_PER_OCT] = {
-    130.813f,
-    138.591f,
-    146.832f,
-    155.563f,
-    164.814f,
-    174.614f,
-    184.997f,
-    195.998f,
-    207.652f,
-    220.00f,
-    233.082f,
-    246.942f,
-};
-
-float note_to_freq(uint8_t note) {
-    if(note == NOTE_NONE) return 0.0f;
-    note = note - NOTE_C2;
-    uint8_t octave = note / NOTES_PER_OCT;
-    uint8_t note_in_oct = note % NOTES_PER_OCT;
-    return notes_oct[note_in_oct] * (1 << octave);
-}
-
-float frequency_offset_semitones(float frequency, uint8_t semitones) {
-    return frequency * (1.0f + ((1.0f / 12.0f) * semitones));
-}
-
-float frequency_get_seventh_of_a_semitone(float frequency) {
-    return frequency * ((1.0f / 12.0f) / 7.0f);
-}
-
-#define PATTERN_SIZE 64
-
-typedef struct {
-    NoteRecord notes[PATTERN_SIZE];
-} NoteRow;
-
-typedef struct {
-    uint8_t row_count;
-    NoteRow* rows;
-} NotePattern;
-
-NoteRow _row = {
-    .notes =
-        {
-            //
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_C3, 0, 0),
-            RECORD_MAKE(NOTE_F2, 0, 0),
-            RECORD_MAKE(NOTE_C3, 0, 0),
-            //
-            RECORD_MAKE(NOTE_E4, 0, 0),
-            RECORD_MAKE(NOTE_C3, 0, 0),
-            RECORD_MAKE(NOTE_E4, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(NOTE_E5, 0, 0),
-            RECORD_MAKE(NOTE_E5, 0, 0),
-            RECORD_MAKE(NOTE_E5, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(NOTE_D5, 0, 0),
-            RECORD_MAKE(NOTE_C3, 0, 0),
-            RECORD_MAKE(NOTE_F2, 0, 0),
-            RECORD_MAKE(NOTE_C3, 0, 0),
-            //
-            RECORD_MAKE(NOTE_C5, 0, 0),
-            RECORD_MAKE(NOTE_C3, 0, 0),
-            RECORD_MAKE(NOTE_C5, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            //
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(NOTE_B4, 0, 0),
-            RECORD_MAKE(NOTE_D3, 0, 0),
-            RECORD_MAKE(NOTE_G2, 0, 0),
-            RECORD_MAKE(NOTE_D3, 0, 0),
-            //
-            RECORD_MAKE(NOTE_E4, 0, 0),
-            RECORD_MAKE(NOTE_D3, 0, 0),
-            RECORD_MAKE(NOTE_E4, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(NOTE_E5, 0, 0),
-            RECORD_MAKE(NOTE_E5, 0, 0),
-            RECORD_MAKE(NOTE_E5, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(NOTE_D5, 0, 0),
-            RECORD_MAKE(NOTE_D3, 0, 0),
-            RECORD_MAKE(NOTE_G2, 0, 0),
-            RECORD_MAKE(NOTE_D3, 0, 0),
-            //
-            RECORD_MAKE(NOTE_C5, 0, 0),
-            RECORD_MAKE(NOTE_D3, 0, 0),
-            RECORD_MAKE(NOTE_C5, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            //
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_A4, 0, 0),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-        },
+#include "tracker_engine/tracker.h"
+
+// Channel row = {
+//     .notes =
+//         {
+//             //
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_C3, 0, 0),
+//             ROW_MAKE(NOTE_F2, 0, 0),
+//             ROW_MAKE(NOTE_C3, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_E4, 0, 0),
+//             ROW_MAKE(NOTE_C3, 0, 0),
+//             ROW_MAKE(NOTE_E4, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_E5, 0, 0),
+//             ROW_MAKE(NOTE_E5, 0, 0),
+//             ROW_MAKE(NOTE_E5, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_D5, 0, 0),
+//             ROW_MAKE(NOTE_C3, 0, 0),
+//             ROW_MAKE(NOTE_F2, 0, 0),
+//             ROW_MAKE(NOTE_C3, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_C5, 0, 0),
+//             ROW_MAKE(NOTE_C3, 0, 0),
+//             ROW_MAKE(NOTE_C5, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(0, 0, 0),
+//             ROW_MAKE(0, 0, 0),
+//             ROW_MAKE(0, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_B4, 0, 0),
+//             ROW_MAKE(NOTE_D3, 0, 0),
+//             ROW_MAKE(NOTE_G2, 0, 0),
+//             ROW_MAKE(NOTE_D3, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_E4, 0, 0),
+//             ROW_MAKE(NOTE_D3, 0, 0),
+//             ROW_MAKE(NOTE_E4, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_E5, 0, 0),
+//             ROW_MAKE(NOTE_E5, 0, 0),
+//             ROW_MAKE(NOTE_E5, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_D5, 0, 0),
+//             ROW_MAKE(NOTE_D3, 0, 0),
+//             ROW_MAKE(NOTE_G2, 0, 0),
+//             ROW_MAKE(NOTE_D3, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_C5, 0, 0),
+//             ROW_MAKE(NOTE_D3, 0, 0),
+//             ROW_MAKE(NOTE_C5, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(0, 0, 0),
+//             ROW_MAKE(0, 0, 0),
+//             ROW_MAKE(0, 0, 0),
+//             //
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_A4, 0, 0),
+//             ROW_MAKE(NOTE_OFF, 0, 0),
+//         },
+// };
+
+Channel channels[] = {
+    {
+        .rows =
+            {
+                // 1/4
+                ROW_MAKE(NOTE_C3, EffectArpeggio, EFFECT_DATA_2(4, 7)),
+                ROW_MAKE(0, EffectArpeggio, EFFECT_DATA_2(4, 7)),
+                ROW_MAKE(NOTE_C4, EffectSlideToNote, 0x20),
+                ROW_MAKE(0, EffectSlideToNote, 0x20),
+                //
+                ROW_MAKE(0, EffectSlideToNote, 0x20),
+                ROW_MAKE(0, EffectSlideToNote, 0x20),
+                ROW_MAKE(0, EffectSlideToNote, 0x20),
+                ROW_MAKE(0, EffectSlideToNote, 0x20),
+                //
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(1, 1)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(1, 1)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(1, 1)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(1, 1)),
+                //
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(2, 2)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(2, 2)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(2, 2)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(2, 2)),
+                // 2/4
+                ROW_MAKE(NOTE_C3, EffectSlideDown, 0x20),
+                ROW_MAKE(0, EffectSlideDown, 0x20),
+                ROW_MAKE(NOTE_C4, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                //
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                //
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                //
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                ROW_MAKE(NOTE_OFF, EffectVibrato, EFFECT_DATA_2(3, 3)),
+                // 3/4
+                ROW_MAKE(NOTE_C3, EffectArpeggio, EFFECT_DATA_2(4, 7)),
+                ROW_MAKE(0, EffectArpeggio, EFFECT_DATA_2(4, 7)),
+                ROW_MAKE(NOTE_OFF, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                //
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                //
+                ROW_MAKE(NOTE_C2, EffectPWM, 60),
+                ROW_MAKE(0, EffectPWM, 32),
+                ROW_MAKE(0, EffectPWM, 12),
+                ROW_MAKE(NOTE_OFF, 0, 0),
+                //
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                // 4/4
+                ROW_MAKE(NOTE_C3, EffectSlideDown, 0x20),
+                ROW_MAKE(0, EffectSlideDown, 0x20),
+                ROW_MAKE(0, EffectSlideDown, 0x20),
+                ROW_MAKE(NOTE_OFF, 0, 0),
+                //
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                //
+                ROW_MAKE(NOTE_C2, EffectPWM, 60),
+                ROW_MAKE(0, EffectPWM, 32),
+                ROW_MAKE(0, EffectPWM, 12),
+                ROW_MAKE(NOTE_OFF, 0, 0),
+                //
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+                ROW_MAKE(0, 0, 0),
+            },
+    },
 };
 
-const uint8_t test = 0x20;
-
-NoteRow row = {
-    .notes =
-        {
-            // 1/4
-            RECORD_MAKE(NOTE_C3, EffectArpeggio, EFFECT_DATA_2(4, 7)),
-            RECORD_MAKE(0, EffectArpeggio, EFFECT_DATA_2(4, 7)),
-            RECORD_MAKE(NOTE_C4, EffectSlideToNote, test),
-            RECORD_MAKE(0, EffectSlideToNote, test),
-            //
-            RECORD_MAKE(0, EffectSlideToNote, test),
-            RECORD_MAKE(0, EffectSlideToNote, test),
-            RECORD_MAKE(0, EffectSlideToNote, test),
-            RECORD_MAKE(0, EffectSlideToNote, test),
-            //
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(1, 1)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(1, 1)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(1, 1)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(1, 1)),
-            //
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(2, 2)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(2, 2)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(2, 2)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(2, 2)),
-            // 2/4
-            RECORD_MAKE(NOTE_C3, EffectSlideDown, 0x20),
-            RECORD_MAKE(0, EffectSlideDown, 0x20),
-            RECORD_MAKE(NOTE_C4, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            //
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            //
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            //
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(0, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            RECORD_MAKE(NOTE_OFF, EffectVibrato, EFFECT_DATA_2(3, 3)),
-            // 3/4
-            RECORD_MAKE(NOTE_C3, EffectArpeggio, EFFECT_DATA_2(4, 7)),
-            RECORD_MAKE(0, EffectArpeggio, EFFECT_DATA_2(4, 7)),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            //
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            //
-            RECORD_MAKE(NOTE_C2, EffectPWM, 60),
-            RECORD_MAKE(0, EffectPWM, 32),
-            RECORD_MAKE(0, EffectPWM, 12),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            // 4/4
-            RECORD_MAKE(NOTE_C3, EffectSlideDown, 0x20),
-            RECORD_MAKE(0, EffectSlideDown, 0x20),
-            RECORD_MAKE(0, EffectSlideDown, 0x20),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            //
-            RECORD_MAKE(NOTE_C2, EffectPWM, 60),
-            RECORD_MAKE(0, EffectPWM, 32),
-            RECORD_MAKE(0, EffectPWM, 12),
-            RECORD_MAKE(NOTE_OFF, 0, 0),
-            //
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-            RECORD_MAKE(0, 0, 0),
-        },
+Pattern patterns[] = {
+    {
+        .channels = channels,
+    },
 };
 
-typedef struct {
-    uint8_t tick;
-    uint8_t tick_limit;
-    uint8_t row;
-} SongState;
-
-SongState song_state = {
-    .tick = 0,
-    .tick_limit = 2,
-    .row = 0,
+uint8_t order_list[] = {
+    0,
+    0,
 };
 
-typedef struct {
-    uint8_t speed;
-    uint8_t depth;
-    int8_t direction;
-    int8_t value;
-} IntegerOscillator;
+Song song = {
+    .channels_count = 1,
+    .patterns_count = 1,
+    .patterns = patterns,
 
-typedef struct {
-    float frequency;
-    float frequency_target;
-    float pwm;
-    bool play;
-    IntegerOscillator vibrato;
-} ChannelState;
+    .order_list_size = 2,
+    .order_list = order_list,
 
-ChannelState ch_state = {
-    .frequency = 0,
-    .frequency_target = FREQUENCY_UNSET,
-    .pwm = PWM_DEFAULT,
-    .play = false,
-    .vibrato =
-        {
-            .speed = 0,
-            .depth = 0,
-            .direction = 0,
-            .value = 0,
-        },
+    .ticks_per_second = 60,
 };
 
-void tracker_interrupt_body() {
-    uint8_t note = record_get_note(row.notes[song_state.row]);
-    uint8_t effect = record_get_effect(row.notes[song_state.row]);
-    uint8_t data = record_get_effect_data(row.notes[song_state.row]);
-
-    // load frequency from note at tick 0
-    if(song_state.tick == 0) {
-        // handle "on first tick" effects
-        if(effect == EffectBreakPattern) {
-            // TODO: advance to next pattern
-            song_state.row = data;
-
-            // reload note and effect
-            note = record_get_note(row.notes[song_state.row]);
-            effect = record_get_effect(row.notes[song_state.row]);
-            data = record_get_effect_data(row.notes[song_state.row]);
-        }
-
-        if(effect == EffectJumpToPattern) {
-            // TODO: advance to pattern[data]
-
-            // reload note and effect
-            note = record_get_note(row.notes[song_state.row]);
-            effect = record_get_effect(row.notes[song_state.row]);
-            data = record_get_effect_data(row.notes[song_state.row]);
-        }
-
-        // no "else", cos previous effects reloads the effect value
-        if(effect == EffectSetSpeed) {
-            song_state.tick_limit = data;
-        }
-
-        // handle note effects
-        if(note == NOTE_OFF) {
-            ch_state.play = false;
-        } else if((note > NOTE_NONE) && (note < NOTE_OFF)) {
-            ch_state.play = true;
-
-            // reset vibrato
-            ch_state.vibrato.speed = 0;
-            ch_state.vibrato.depth = 0;
-            ch_state.vibrato.value = 0;
-            ch_state.vibrato.direction = 0;
-
-            // reset pwm
-            ch_state.pwm = PWM_DEFAULT;
-
-            if(effect == EffectSlideToNote) {
-                ch_state.frequency_target = note_to_freq(note);
-            } else {
-                ch_state.frequency = note_to_freq(note);
-                ch_state.frequency_target = FREQUENCY_UNSET;
-            }
-        }
-    }
-
-    if(ch_state.play) {
-        float frequency, pwm;
-
-        if((effect == EffectSlideUp || effect == EffectSlideDown) && data != EFFECT_DATA_NONE) {
-            // apply slide effect
-            ch_state.frequency += (effect == EffectSlideUp ? 1 : -1) * data;
-        } else if(effect == EffectSlideToNote) {
-            // apply slide to note effect, if target frequency is set
-            if(ch_state.frequency_target > 0) {
-                if(ch_state.frequency_target > ch_state.frequency) {
-                    ch_state.frequency += data;
-                    if(ch_state.frequency > ch_state.frequency_target) {
-                        ch_state.frequency = ch_state.frequency_target;
-                        ch_state.frequency_target = FREQUENCY_UNSET;
-                    }
-                } else if(ch_state.frequency_target < ch_state.frequency) {
-                    ch_state.frequency -= data;
-                    if(ch_state.frequency < ch_state.frequency_target) {
-                        ch_state.frequency = ch_state.frequency_target;
-                        ch_state.frequency_target = FREQUENCY_UNSET;
-                    }
-                }
-            }
-        }
-
-        frequency = ch_state.frequency;
-        pwm = ch_state.pwm;
-
-        // apply arpeggio effect
-        if(effect == EffectArpeggio) {
-            if(data != EFFECT_DATA_NONE) {
-                if((song_state.tick % 3) == 1) {
-                    uint8_t note_offset = EFFECT_DATA_GET_X(data);
-                    frequency = frequency_offset_semitones(frequency, note_offset);
-                } else if((song_state.tick % 3) == 2) {
-                    uint8_t note_offset = EFFECT_DATA_GET_Y(data);
-                    frequency = frequency_offset_semitones(frequency, note_offset);
-                }
-            }
-        } else if(effect == EffectVibrato) {
-            // apply vibrato effect, data = speed, depth
-            uint8_t vibrato_speed = EFFECT_DATA_GET_X(data);
-            uint8_t vibrato_depth = EFFECT_DATA_GET_Y(data);
-
-            // update vibrato parameters if speed or depth is non-zero
-            if(vibrato_speed != 0) ch_state.vibrato.speed = vibrato_speed;
-            if(vibrato_depth != 0) ch_state.vibrato.depth = vibrato_depth;
-
-            // update vibrato value
-            ch_state.vibrato.value += ch_state.vibrato.direction * ch_state.vibrato.speed;
-
-            // change direction if value is at the limit
-            if(ch_state.vibrato.value > ch_state.vibrato.depth) {
-                ch_state.vibrato.direction = -1;
-            } else if(ch_state.vibrato.value < -ch_state.vibrato.depth) {
-                ch_state.vibrato.direction = 1;
-            } else if(ch_state.vibrato.direction == 0) {
-                // set initial direction, if it is not set
-                ch_state.vibrato.direction = 1;
-            }
-
-            frequency += (frequency_get_seventh_of_a_semitone(frequency) * ch_state.vibrato.value);
-        } else if(effect == EffectPWM) {
-            pwm = (pwm - PWM_MIN) / EFFECT_DATA_1_MAX * data + PWM_MIN;
-        }
-
-        tracker_speaker_play(frequency, pwm);
-    } else {
-        tracker_speaker_stop();
-    }
-
-    song_state.tick++;
-    if(song_state.tick >= song_state.tick_limit) {
-        song_state.tick = 0;
-
-        // next note
-        song_state.row = (song_state.row + 1) % PATTERN_SIZE;
-        //TODO: advance to next pattern
-    }
-}
-
-void tracker_interrupt_cb() {
-    tracker_debug_set(true);
-    tracker_interrupt_body();
-    tracker_debug_set(false);
-}
-
 int32_t zero_tracker_app(void* p) {
     UNUSED(p);
 
-    tracker_debug_init();
-    tracker_speaker_init();
-    tracker_interrupt_init(60.0f, tracker_interrupt_cb, NULL);
+    Tracker* tracker = tracker_alloc();
+    tracker_set_song(tracker, &song);
+    tracker_start(tracker);
 
     while(1) {
         furi_delay_ms(1000);
     }
 
+    tracker_stop(tracker);
+    tracker_free(tracker);
+
     return 0;
 }