Counter based debouncing

Marlin/src/lcd/marlinui.cpp

@@ -1389,7 +1389,10 @@ void MarlinUI::init() {
 #if MARLINUI_ENCODER_DELTA
 
   #define ENCODER_DEBOUNCE_MS 2
-
+  #ifdef ENCODER_DEBOUNCE_MS
+    // #define USE_TIME_BLOCKING_DEBOUNCING
+    #define USE_COUNTER_DEBOUNCING
+  #endif
   /**
    * Get the encoder delta (-2 -1 0 +1 +2) since the last call, reading the live encoder state.
    * Pins may be debounced to filter noise.
@@ -1400,7 +1403,33 @@ void MarlinUI::init() {
 
     const enc_t live_enc = { BUTTON_PRESSED(EN1), BUTTON_PRESSED(EN2) };
 
-    #if ENCODER_DEBOUNCE_MS
+    #if defined(USE_COUNTER_DEBOUNCING)
+      static uint16_t counter;
+      counter++;
+
+      static int dt_us = 500;  // the time delta in us between each run of this function
+      if (counter == 1000){
+        static millis_t last_ms;
+        dt_us = (now-last_ms);
+        last_ms = now;
+        counter = 0;
+      }
+
+      static enc_t enc;
+      #define THRESHOLD (ENCODER_DEBOUNCE_MS * 1000 / 2)
+      static int16_t btn_a_counter = 0;
+      if (btn_a_counter < THRESHOLD && live_enc.a) btn_a_counter += dt_us;
+      else if (btn_a_counter > -THRESHOLD && !live_enc.a) btn_a_counter -= dt_us;
+      if (btn_a_counter >= THRESHOLD) enc.a = 1;
+      else if (btn_a_counter <= -THRESHOLD) enc.a = 0;
+
+      static int16_t btn_b_counter = 0;
+      if (btn_b_counter < THRESHOLD && live_enc.b) btn_b_counter += dt_us;
+      else if (btn_b_counter > -THRESHOLD && !live_enc.b) btn_b_counter -= dt_us;
+      if (btn_b_counter >= THRESHOLD) enc.b = 1;
+      else if (btn_b_counter <= -THRESHOLD) enc.b = 0;
+
+    #elif defined(USE_TIME_BLOCK_DEBOUNCING)
 
       static enc_t enc, old_live;
       static millis_t bounce_ms;