Fix clock latency: process one USB packet per update() — no more batch-processing 0xF8 bursts

src/midi_transport.cpp

@@ -50,7 +50,7 @@ void UsbMidiTransport::update() {
                       TinyUSBDevice.mounted() ? "YES" : "NO");
     }
 
-    while (usb_midi.available()) {
+    if (usb_midi.available()) {
         uint8_t packet[4];
         if (usb_midi.readPacket(packet)) {
             uint8_t cin = packet[0] & 0x0F;
@@ -58,12 +58,10 @@ void UsbMidiTransport::update() {
                 if (packet[1] == 0xF8) {
                     midi_tick_count++;
                 } else if (packet[1] == 0xFA) {
-                    midi_tick_count = 0;
+                    midi_tick_count = 0xFFFFFFFF;
-                    Serial.println("[CLK] START - reset tick to 0");
+                    Serial.println("[CLK] START - next F8 = tick 0");
                 }
-                continue;
+            } else {
-            }
-
                 MidiEvent event;
                 parse_midi_packet(packet, 4, event);
 
@@ -84,6 +82,7 @@ void UsbMidiTransport::update() {
             }
         }
     }
+}
 
 void UsbMidiTransport::on_midi_receive(std::function<void(const MidiEvent&)> callback) {
     receive_callback = callback;