Midi clock and tempo

RP2040_Tracker.ino

@@ -52,16 +52,17 @@ enum UIState {
   UI_MENU_MAIN,
   UI_MENU_RANDOMIZE,
   UI_MENU_SETUP,
-  UI_SETUP_CHANNEL_EDIT
+  UI_SETUP_CHANNEL_EDIT,
+  UI_SETUP_TEMPO_EDIT
 };
 
-UIState currentState = UI_TRACKER;
+UIState currentState = UI_MENU_MAIN;
 
 const char* mainMenu[] = { "Tracker", "Randomize", "Setup" };
 const int mainMenuCount = sizeof(mainMenu) / sizeof(char*);
 const char* randomizeMenu[] = { "Back", "Scale", "Melody", "Theme 1", "Theme 2", "Theme 3", "Theme 4", "Theme 5", "Theme 6", "Theme 7" };
 const int randomizeMenuCount = sizeof(randomizeMenu) / sizeof(char*);
-const char* setupMenu[] = { "Back", "Channel", "Save", "Load" };
+const char* setupMenu[] = { "Back", "Channel", "Tempo", "Save", "Load" };
 const int setupMenuCount = sizeof(setupMenu) / sizeof(char*);
 
 int menuSelection = 0;
@@ -77,8 +78,9 @@ const uint32_t EEPROM_MAGIC = 0x42424244;
 volatile bool isEditing = false;
 volatile int scrollOffset = 0;
 volatile bool isPlaying = false;
-unsigned long lastStepTime = 0;
 volatile int tempo = 120; // BPM
+volatile unsigned long lastClockTime = 0;
+volatile int clockCount = 0;
 
 
 // Encoder State
@@ -238,6 +240,12 @@ void sendMidi(uint8_t status, uint8_t note, uint8_t velocity) {
   Serial1.write(velocity);
 }
 
+void sendMidiRealtime(uint8_t status) {
+  mutex_enter_blocking(&midiMutex);
+  Serial1.write(status);
+  mutex_exit(&midiMutex);
+}
+
 void generateRandomScale() {
   numScaleNotes = random(3, 13); // 3 to 12 notes
   for (int i = 0; i < 12; i++) {
@@ -325,6 +333,11 @@ void handleInput() {
         if (midiChannel < 1) midiChannel = 16;
         if (midiChannel > 16) midiChannel = 1;
         break;
+      case UI_SETUP_TEMPO_EDIT:
+        tempo += delta;
+        if (tempo < 40) tempo = 40;
+        if (tempo > 240) tempo = 240;
+        break;
     }
   }
 
@@ -379,11 +392,12 @@ void handleInput() {
             case UI_MENU_SETUP:
               if (menuSelection == 0) { currentState = UI_MENU_MAIN; menuSelection = 2; }
               if (menuSelection == 1) currentState = UI_SETUP_CHANNEL_EDIT;
-              if (menuSelection == 2) { 
+              if (menuSelection == 2) currentState = UI_SETUP_TEMPO_EDIT;
+              if (menuSelection == 3) { 
                 saveSequence(); 
                 currentState = UI_MENU_MAIN; 
               }
-              if (menuSelection == 3) { 
+              if (menuSelection == 4) { 
                 if (loadSequence()) showMessage("LOADED!"); 
                 currentState = UI_MENU_MAIN; 
               }
@@ -391,6 +405,9 @@ void handleInput() {
             case UI_SETUP_CHANNEL_EDIT:
               currentState = UI_MENU_SETUP;
               break;
+            case UI_SETUP_TEMPO_EDIT:
+              currentState = UI_MENU_SETUP;
+              break;
           }
        }
     }
@@ -405,10 +422,13 @@ void handleInput() {
       Serial.print(F("Playback: ")); Serial.println(isPlaying ? F("ON") : F("OFF"));
       if (isPlaying) {
         playbackStep = navigationSelection > 0 ? navigationSelection - 1 : 0;
-        lastStepTime = millis(); // Reset timer to start immediately
+        clockCount = 0;
+        lastClockTime = micros();
+        sendMidiRealtime(0xFA); // MIDI Start
       } else {
         // Send All Notes Off on stop (CC 123)
         needsPanic = true;
+        sendMidiRealtime(0xFC); // MIDI Stop
         queuedTheme = -1;
       }
     }
@@ -420,9 +440,17 @@ void handleInput() {
 void handlePlayback() {
   if (!isPlaying) return;
 
-  unsigned long interval = 15000 / tempo; // 16th notes (60000 / tempo / 4)
+  unsigned long currentMicros = micros();
-  if (millis() - lastStepTime > interval) {
+  unsigned long clockInterval = 2500000 / tempo; // 60s * 1000000us / (tempo * 24ppqn)
-    lastStepTime = millis();
+
+  if (currentMicros - lastClockTime >= clockInterval) {
+    lastClockTime += clockInterval;
+    
+    sendMidiRealtime(0xF8); // MIDI Clock
+
+    clockCount++;
+    if (clockCount < 6) return; // 24 ppqn / 4 = 6 pulses per 16th note
+    clockCount = 0;
 
     mutex_enter_blocking(&midiMutex);
 
@@ -492,6 +520,11 @@ void drawMenu(const char* title, const char* items[], int count, int selection)
         display.print(F(": "));
         display.print(midiChannel);
     }
+    // Special case for tempo display
+    if (currentState == UI_MENU_SETUP && i == 2) {
+        display.print(F(": "));
+        display.print(tempo);
+    }
 
     // Special case for queued theme
     if (currentState == UI_MENU_RANDOMIZE && i >= 3 && queuedTheme == (i - 2)) {
@@ -623,6 +656,17 @@ void drawUI() {
       display.setCursor(0, 50);
       display.println(F(" (Press to confirm)"));
       break;
+    case UI_SETUP_TEMPO_EDIT:
+      display.println(F("SET TEMPO"));
+      display.drawLine(0, 8, 128, 8, SSD1306_WHITE);
+      display.setCursor(20, 25);
+      display.setTextSize(2);
+      display.print(F("BPM: "));
+      display.print(tempo);
+      display.setTextSize(1);
+      display.setCursor(0, 50);
+      display.println(F(" (Press to confirm)"));
+      break;
   }
 
   display.display();