Add initial Analogue MIDI sync functionality (needs options)

3 files changed, 20 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index 960a8a6..3486200 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-dev-01
+TARGET         := STEPPER-v1.8-dev-02
 ELF            := $(BUILD_DIR)/$(TARGET).elf
 BIN            := $(BUILD_DIR)/$(TARGET).gba
 
diff --git a/src/sequencer.c b/src/sequencer.c
index 11c0f5a..9dcaa89 100644
--- a/src/sequencer.c
+++ b/src/sequencer.c
@@ -346,9 +346,9 @@ play_step(void) {
     step_counter = (step_counter + 1) % 16;
 }
 
-static nseq_ticks = 0;
 void
 sequencer_tick(void) {
+    static int nseq_ticks = 0;
     if (nseq_ticks++ < 24) {
         return;
     }
@@ -1549,10 +1549,24 @@ handle_sequencer_input(void) {
     }
 }
 
+static int in_ticks = 0;
+
+void
+reset_serial_in(void) {
+    in_ticks = 0;
+}
+
 void
-serial_irq() {
+serial_irq(void) {
     if (play_status) {
-        play_step();
+        if (in_ticks++ == 0) {
+            // TODO: Instead of play_step use the nseq_ticks instead!
+            play_step();
+            // MIDI: 24 / 8 = 3
+            // set to 6 for half tempo
+        } else if (in_ticks == 3) {
+            in_ticks = 0;
+        }
     }
 }
 
diff --git a/src/settings.c b/src/settings.c
index 374618c..7cebcf6 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -8,6 +8,7 @@ static Settings settings = {
 };
 static int settings_cursor_loc = 0;
 
+void reset_serial_in(void);
 void serial_irq(void);
 void stop_sound(void);
 void toggle_playing(void);
@@ -16,6 +17,7 @@ void
 set_audio_settings(void) {
     stop_sound();
     if (settings.sync == SYNC_IN_LINK) {
+        reset_serial_in();
         irs_set(IRQ_SERIAL, serial_irq);
         irs_set(IRQ_TIMER_2, NULL);
         SIO_MODE = SIO_MODE_GP