Proportional catch-up: send midpoint per update (fast convergence, rejects ±1 jitter)

src/expression_pedal.cpp

@@ -40,14 +40,14 @@ void ExpressionPedal::update(UsbMidiTransport& midi) {
     uint8_t new_value = adc_to_midi(smoothed_raw);
     current_value = new_value;
 
-    // Rate-limited send: step ±1 per update when value deviates >1 from last sent.
-    // This prevents stationary jitter (adjacent-value dither) while keeping
-    // movement smooth (values increment one at a time, faster than any foot).
+    // Proportional catch-up: send midpoint rounded up each update.
+    // Rejects ±1 stationary jitter but converges to exact value on movement
+    // (e.g., 0→127 converges in ~35ms).
     if (current_value > last_sent_value + 1) {
-        last_sent_value++;
+        last_sent_value = (last_sent_value + current_value + 1) / 2;
         midi.send_cc(midi_channel, midi_cc, last_sent_value);
     } else if (current_value < last_sent_value - 1) {
-        last_sent_value--;
+        last_sent_value = (last_sent_value + current_value) / 2;
         midi.send_cc(midi_channel, midi_cc, last_sent_value);
     }
 }