Staging some testing samples for backuplsdjsync

3 files changed, 219 insertions, 38 deletions

diff --git a/Makefile b/Makefile
index e464b75..abaa008 100644
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,7 @@ INC_FLAGS   := $(addprefix -I,$(INC_DIRS))
 INC_FLAGS   += -I$(LIBGBA_SRC)
 
 # Output library names and executables.
-TARGET         := STEPPER-v1.8
+TARGET         := STEPPER-v1.8-dev-lsdj
 ELF            := $(BUILD_DIR)/$(TARGET).elf
 BIN            := $(BUILD_DIR)/$(TARGET).gba
 
diff --git a/src/main.c b/src/main.c
index 170e0e0..81e47a1 100644
--- a/src/main.c
+++ b/src/main.c
@@ -255,7 +255,7 @@ main(void) {
 
     // Register interrupts.
     irq_init();
-    irs_set(IRQ_VBLANK, sound_vsync);
+    irs_set(IRQ_VBLANK, irs_stub);
 
     // Initialize sequencer.
     sequencer_init();
diff --git a/src/sequencer.c b/src/sequencer.c
index 9efd506..d2a0054 100644
--- a/src/sequencer.c
+++ b/src/sequencer.c
@@ -25,32 +25,185 @@ clear_pattern(size_t idx) {
 
 void
 gate_off(void) {
-    SIO_MODE = SIO_MODE_GP
-        | SIO_SC_OUT(1)
-        | SIO_SD_OUT(1)
-        | SIO_SI_OUT(0)
-        | SIO_SO_OUT(1)
-        | SIO_SC(0)
-        | SIO_SD(0)
-        | SIO_SO(0);
-    TIMER_CTRL_3 = 0;
+    // SIO_MODE = SIO_MODE_GP
+    //     | SIO_SC_OUT(1)
+    //     | SIO_SD_OUT(0)
+    //     | SIO_SI_OUT(0)
+    //     | SIO_SO_OUT(0)
+    //     | SIO_SI(0)
+    //     | SIO_SC(0)
+    //     | SIO_SD(0)
+    //     | SIO_SO(0);
+    // TIMER_CTRL_3 = 0;
+}
+
+int pulses_sent = 0;
+int gate_status = 0;
+
+void
+gate_lsdj(void) {
+    gate_status ^= 1;
+    if (pulses_sent >= 7) {
+        gate_off();
+        return;
+    }
+    if (gate_status == 1) {
+        gate_off();
+    } else {
+        pulses_sent++;
+        SIO_MODE = SIO_MODE_GP
+            | SIO_SC_OUT(1)
+            | SIO_SD_OUT(0)
+            | SIO_SI_OUT(0)
+            | SIO_SO_OUT(0)
+            | SIO_SI(0)
+            | SIO_SC(1)
+            | SIO_SD(0)
+            | SIO_SO(0);
+    }
+    int n_ticks = -80 / 8 / 2; // 5ms
+    irs_set(IRQ_TIMER_3, gate_lsdj);
+    TIMER_DATA_3 = n_ticks;
+    TIMER_CTRL_3 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
 }
 
+// TODO: LSDJ sync pulse?
+
 void
 gate_on(void) {
-    gate_off();
+    // SYNC24 NOTES
+    // (from https://e-rm.de/data/E-RM_report_HowToDinSync_10_14_EN.pdf)
+    //
+    // "Moreover, a duty cycle of 50% doesn’t seem to be nescessary, all tested
+    // machines were able to sync properly to clock ticks with a positive width
+    // of 5 ms to up to 300 BPM" @ 24bpq
+    //
+    // int bpm = 100;
+    // if (settings.global_bpm) {
+    //     bpm = settings.bpm;
+    // } else {
+    //     bpm patterns[current_pattern].bpm;
+    // }
+    // gate_off();
+    // pulses_sent = 0;
+    // gate_status = 0;
+    // SIO_MODE = SIO_MODE_GP
+    //     | SIO_SC_OUT(1)
+    //     | SIO_SD_OUT(0)
+    //     | SIO_SI_OUT(0)
+    //     | SIO_SO_OUT(0)
+    //     | SIO_SI(0)
+    //     | SIO_SC(1)
+    //     | SIO_SD(0)
+    //     | SIO_SO(0);
+    // // int n_ticks = -80; // 5ms
+    // // irs_set(IRQ_TIMER_3, gate_off);
+    // // TIMER_DATA_3 = n_ticks;
+    // // TIMER_CTRL_3 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
+    // int n_ticks = -80 / 8 / 2; // 5ms
+    // irs_set(IRQ_TIMER_3, gate_lsdj);
+    // TIMER_DATA_3 = n_ticks;
+    // TIMER_CTRL_3 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
+    // int n_ticks = -79; // 5ms
+    // TIMER_DATA_3 = n_ticks;
+    // TIMER_CTRL_3 = TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
+    // while (1) {
+    //     int cnt = TIMER_DATA_3;
+    //     if (cnt >= 80) {
+    //         gate_off();
+    //         break;
+    //     }
+    // }
+}
+
+bool first_pulse = true;
+int so_status = 1;
+
+void
+lsdj_toggle(void) {
+    gate_status ^= 1;
+    if (pulses_sent >= 7) {
+        TIMER_CTRL_3 = 0;
+        SIO_MODE = SIO_MODE_GP
+            | SIO_SI_OUT(0)
+            | SIO_SC_OUT(1)
+            | SIO_SD_OUT(0)
+            | SIO_SO_OUT(1)
+            | SIO_SI(0)
+            | SIO_SC(1)
+            | SIO_SD(0)
+            | SIO_SO(so_status);
+        return;
+    }
+    if (gate_status == 1) {
+        SIO_MODE = SIO_MODE_GP
+            | SIO_SI_OUT(0)
+            | SIO_SC_OUT(1)
+            | SIO_SD_OUT(0)
+            | SIO_SO_OUT(1)
+            | SIO_SI(0)
+            | SIO_SC(1)
+            | SIO_SD(0)
+            | SIO_SO(so_status);
+    } else {
+        pulses_sent++;
+        SIO_MODE = SIO_MODE_GP
+            | SIO_SI_OUT(0)
+            | SIO_SC_OUT(1)
+            | SIO_SD_OUT(0)
+            | SIO_SO_OUT(1)
+            | SIO_SI(0)
+            | SIO_SC(0)
+            | SIO_SD(0)
+            | SIO_SO(so_status);
+    }
+    TIMER_CTRL_3 = 0;
+    // int n_ticks = -80 / 8 / 2; // 5ms
+    // irs_set(IRQ_TIMER_3, lsdj_toggle);
+    // TIMER_DATA_3 = n_ticks;
+    // TIMER_CTRL_3 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
+    int n_ticks = -9; // 122/2 = 61us; 61 / 3.8 = 16
+    irs_set(IRQ_TIMER_3, lsdj_toggle);
+    TIMER_DATA_3 = n_ticks;
+    TIMER_CTRL_3 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_1;
+}
+
+void
+lsdj_pulse(void) {
+    // LSDJ expects a pulse train on the SC pin (active low?). For the song
+    // start, the first pulse and until the start of the second one it should
+    // set SO to low as follows:
+    //
+    // CLK (SC) --_-_-_-_-_-_-_-_----------------_-_-_-_-_-_-_-_----------------
+    // OUT (SO) --_______________________________-------------------------------
+    //
+    // Additionally, in LSDJ sync mode, SO will go low at the start of each bar.
+    //
+    // The width of the pulse is approximately 915-916us (122us per pulse at 50%
+    // duty cycle of 61us). This sync method is based on sync24, so it should
+    // receive 6 pulses each 1/16th step (96 pulses in a 16 step sequence).
+    if (first_pulse) {
+        first_pulse = false;
+        so_status = 0;
+    } else {
+        so_status = 1;
+    }
+    TIMER_DATA_3 = 0;
+    pulses_sent = 0;
+    gate_status = 0;
     SIO_MODE = SIO_MODE_GP
         | SIO_SC_OUT(1)
-        | SIO_SD_OUT(1)
+        | SIO_SD_OUT(0)
         | SIO_SI_OUT(0)
         | SIO_SO_OUT(1)
-        | SIO_SC(1)
+        | SIO_SI(0)
+        | SIO_SC(0)
         | SIO_SD(0)
-        | SIO_SO(1);
-    int n_ticks = -244181 / 600;
-    irs_set(IRQ_TIMER_3, gate_off);
+        | SIO_SO(so_status);
+    int n_ticks = -9; // 122/2 = 61us; 61 / 3.8 = 16
+    irs_set(IRQ_TIMER_3, lsdj_toggle);
     TIMER_DATA_3 = n_ticks;
-    TIMER_CTRL_3 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
+    TIMER_CTRL_3 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_1;
 }
 
 u8
@@ -475,31 +628,36 @@ env_start:
 
 void
 sequencer_tick(void) {
-    switch (settings.sync) {
-        case SYNC_OUT_LINK_96BPQ: { gate_on(); } break;
-        case SYNC_OUT_LINK_48BPQ: { if (sync_ticks++ % 2 == 0) { gate_on(); } } break;
-        case SYNC_OUT_LINK_24BPQ: { if (sync_ticks++ % 4 == 0) { gate_on(); } } break;
-        case SYNC_OUT_LINK_12BPQ: { if (sync_ticks++ % 8 == 0) { gate_on(); } } break;
-        case SYNC_OUT_LINK_6BPQ: { if (sync_ticks++ % 16 == 0) { gate_on(); } } break;
-        case SYNC_OUT_LINK_4BPQ: { if (sync_ticks++ % 24 == 0) { gate_on(); } } break;
-        case SYNC_OUT_LINK_2BPQ: { if (sync_ticks++ % 48 == 0) { gate_on(); } } break;
-        case SYNC_OUT_AUDIO_12BPQ: { if (sync_ticks++ % 8 == 0) { audio_sync_click = true; } } break;
-        case SYNC_OUT_AUDIO_6BPQ: { if (sync_ticks++ % 16 == 0) { audio_sync_click = true; } } break;
-        case SYNC_OUT_AUDIO_4BPQ: { if (sync_ticks++ % 24 == 0) { audio_sync_click = true; } } break;
-        case SYNC_OUT_AUDIO_2BPQ: { if (sync_ticks++ % 48 == 0) { audio_sync_click = true; } } break;
-        case SYNC_OUT_LINK_AUDIO_12BPQ: { if (sync_ticks++ % 8 == 0) { gate_on(); audio_sync_click = true; } } break;
-        case SYNC_OUT_LINK_AUDIO_6BPQ: { if (sync_ticks++ % 16 == 0) { gate_on(); audio_sync_click = true; } } break;
-        case SYNC_OUT_LINK_AUDIO_4BPQ: { if (sync_ticks++ % 24 == 0) { gate_on(); audio_sync_click = true; } } break;
-        case SYNC_OUT_LINK_AUDIO_2BPQ: { if (sync_ticks++ % 48 == 0) { gate_on(); audio_sync_click = true; } } break;
-        default: break;
-    }
+    // switch (settings.sync) {
+    //     case SYNC_OUT_LINK_96BPQ: { gate_on(); } break;
+    //     case SYNC_OUT_LINK_48BPQ: { if (sync_ticks++ % 2 == 0) { gate_on(); } } break;
+    //     case SYNC_OUT_LINK_24BPQ: { if (sync_ticks++ % 4 == 0) { gate_on(); } } break;
+    //     case SYNC_OUT_LINK_12BPQ: { if (sync_ticks++ % 8 == 0) { gate_on(); } } break;
+    //     case SYNC_OUT_LINK_6BPQ: { if (sync_ticks++ % 16 == 0) { gate_on(); } } break;
+    //     case SYNC_OUT_LINK_4BPQ: { if (sync_ticks++ % 24 == 0) { gate_on(); } } break;
+    //     case SYNC_OUT_LINK_2BPQ: { if (sync_ticks++ % 48 == 0) { gate_on(); } } break;
+    //     case SYNC_OUT_AUDIO_12BPQ: { if (sync_ticks++ % 8 == 0) { audio_sync_click = true; } } break;
+    //     case SYNC_OUT_AUDIO_6BPQ: { if (sync_ticks++ % 16 == 0) { audio_sync_click = true; } } break;
+    //     case SYNC_OUT_AUDIO_4BPQ: { if (sync_ticks++ % 24 == 0) { audio_sync_click = true; } } break;
+    //     case SYNC_OUT_AUDIO_2BPQ: { if (sync_ticks++ % 48 == 0) { audio_sync_click = true; } } break;
+    //     case SYNC_OUT_LINK_AUDIO_12BPQ: { if (sync_ticks++ % 8 == 0) { gate_on(); audio_sync_click = true; } } break;
+    //     case SYNC_OUT_LINK_AUDIO_6BPQ: { if (sync_ticks++ % 16 == 0) { gate_on(); audio_sync_click = true; } } break;
+    //     case SYNC_OUT_LINK_AUDIO_4BPQ: { if (sync_ticks++ % 24 == 0) { gate_on(); audio_sync_click = true; } } break;
+    //     case SYNC_OUT_LINK_AUDIO_2BPQ: { if (sync_ticks++ % 48 == 0) { gate_on(); audio_sync_click = true; } } break;
+    //     default: break;
+    // }
     if (nseq_ticks++ == 0) {
-        play_step();
+        if (step_counter % 16 == 0) {
+            // first_pulse = true;
+        }
+        step_counter = (step_counter + 1) % 16;
+        // play_step();
     }
+    if (sync_ticks++ % 4 == 0) { lsdj_pulse(); }
     if (nseq_ticks == 24) {
         nseq_ticks = 0;
     }
-    wave_ad_tick();
+    // wave_ad_tick();
 }
 
 void
@@ -680,10 +838,23 @@ stop_sound(void) {
     SOUND_NOISE_CTRL = 0;
     redraw_play_pause = true;
     redraw_pattern_buttons = true;
+    SIO_MODE = SIO_MODE_GP
+        | SIO_SI_OUT(0)
+        | SIO_SC_OUT(1)
+        | SIO_SD_OUT(0)
+        | SIO_SO_OUT(1)
+        | SIO_SI(0)
+        | SIO_SC(1)
+        | SIO_SD(0)
+        | SIO_SO(1);
 }
 
 void
 reset_sequencer(void) {
+    first_pulse = true;
+    so_status = 1;
+    gate_status = 0;
+    pulses_sent = 0;
     step_counter = 0;
     nseq_ticks = 0;
     sync_ticks = 0;
@@ -1984,4 +2155,14 @@ sequencer_init(void) {
     SOUND_STATUS = SOUND_ENABLE;
     init_dsound();
     set_audio_settings();
+    // gate_off();
+    SIO_MODE = SIO_MODE_GP
+        | SIO_SC_OUT(1)
+        | SIO_SD_OUT(0)
+        | SIO_SI_OUT(0)
+        | SIO_SO_OUT(1)
+        | SIO_SI(0)
+        | SIO_SC(1)
+        | SIO_SD(0)
+        | SIO_SO(1);
 }