Encoder: handle switch

firmware/src/encoder.cpp

@@ -12,12 +12,16 @@ When rotated clockwise, CLK changes before DT; when rotated counter-clockwise, D
 
 */
 
+#define SW_DEBOUNCE_MS 10
+
 void setupEncoder() {
   pinMode(CLK_PIN, INPUT);
   pinMode(DT_PIN, INPUT);
   pinMode(SW_PIN, INPUT_PULLUP);
 }
 
+void handleSwitch();
+
 void demoEncoder() {
   bool clk = digitalRead(CLK_PIN);
   bool dt = digitalRead(DT_PIN);
@@ -29,4 +33,31 @@ void demoEncoder() {
   Serial.print(dt);
   Serial.print(" SW: ");
   Serial.println(sw);
+
+  handleSwitch();
+}
+
+bool previousPressed = false;
+unsigned long lastChangeAt = 0;
+
+void handleSwitch() {
+  bool isPressed = !digitalRead(SW_PIN);
+
+  // only handle change
+  if (isPressed == previousPressed) {
+    return;
+  }
+
+  // debounce
+  unsigned long now = millis();
+  if (now - lastChangeAt < SW_DEBOUNCE_MS) {
+    return;
+  }
+
+  // save state
+  previousPressed = isPressed;
+  lastChangeAt = now;
+
+  // handle change
+  Serial.println(isPressed ? "Pressed" : "Released");
 }