diff --git a/src/Bounce2.cpp b/src/Bounce2.cpp
index 049452c..2fda2cc 100644
--- a/src/Bounce2.cpp
+++ b/src/Bounce2.cpp
@@ -17,20 +17,25 @@ Bounce::Bounce()
 
 void Bounce::attach(int pin) {
     this->pin = pin;
-    state = 0;
-    if (readCurrentState()) {
-        setStateFlag(DEBOUNCED_STATE | UNSTABLE_STATE);
-    }
-#ifdef BOUNCE_LOCK_OUT
-    previous_millis = 0;
-#else
-    previous_millis = millis();
-#endif
+	bool currentState = readCurrentState();
+	attach(currentState);
 }
 
-void Bounce::attach(int pin, int mode){
-    setPinMode(pin, mode);
-    this->attach(pin);
+void Bounce::attach(int pin, int mode) {
+	setPinMode(pin, mode);
+	this->attach(pin);
+}
+
+void Bounce::attach(bool currentState) {
+	state = 0;
+	if (currentState) {
+		setStateFlag(DEBOUNCED_STATE | UNSTABLE_STATE);
+	}
+#ifdef BOUNCE_LOCK_OUT
+	previous_millis = 0;
+#else
+	previous_millis = millis();
+#endif
 }
 
 void Bounce::interval(uint16_t interval_millis)
@@ -39,6 +44,14 @@ void Bounce::interval(uint16_t interval_millis)
 }
 
 bool Bounce::update()
+{
+	// Read the state of the switch in a temporary variable.
+	bool currentState = readCurrentState();
+
+	update(currentState);
+}
+
+bool Bounce::update(bool currentState)
 {
 
     unsetStateFlag(CHANGED_STATE);
@@ -46,7 +59,6 @@ bool Bounce::update()
     
     // Ignore everything if we are locked out
     if (millis() - previous_millis >= interval_millis) {
-        bool currentState = readCurrentState();
         if ( currentState != getStateFlag(DEBOUNCED_STATE) ) {
             previous_millis = millis();
             changeState();
@@ -55,9 +67,6 @@ bool Bounce::update()
     
 
 #elif defined BOUNCE_WITH_PROMPT_DETECTION
-    // Read the state of the switch port into a temporary variable.
-    bool readState = readCurrentState();
-
 
     if ( readState != getStateFlag(DEBOUNCED_STATE) ) {
       // We have seen a change from the current button state.
@@ -81,10 +90,6 @@ bool Bounce::update()
     
     
 #else
-    // Read the state of the switch in a temporary variable.
-    bool currentState = readCurrentState();
-    
-
     // If the reading is different from last reading, reset the debounce counter
     if ( currentState != getStateFlag(UNSTABLE_STATE) ) {
         previous_millis = millis();
diff --git a/src/Bounce2.h b/src/Bounce2.h
index da3d429..ce3674e 100644
--- a/src/Bounce2.h
+++ b/src/Bounce2.h
@@ -93,11 +93,19 @@ class Bounce
 */
     void attach(int pin, int mode);
 
-    /**
-    Attach to a pin for advanced users. Only attach the pin this way once you have previously set it up. Otherwise use attach(int pin, int mode).
-    */
-    void attach(int pin);
-    
+	/**
+	Attach to a pin for advanced users. Only attach the pin this way once you have previously set it up. Otherwise use attach(int pin, int mode).
+	*/
+	void attach(int pin);
+
+	/**
+	@brief  current values are provides externally from this library (eg from shifting registred). readDigital can be slow when reading a lot of buttons
+            
+    @param    currentValue
+
+	*/
+	void attach(bool currentValue);
+
 
     /**
     @brief  Sets the debounce interval in milliseconds.
@@ -117,10 +125,19 @@ class Bounce
     @return True if the pin changed state.
 */
 
-    bool update();
+	bool update();
+
+	/*!
+		@brief    "update" the object state value externally. This has to be done as often as possible (that means to include it in your loop()). Only call update() once per loop().
+
+		@return True if the pin changed state.
+	*/
+	bool update(bool currentValue);
 
     /**
-     @brief Returns the pin's state (HIGH or LOW).
+     @brief Returns the pin's state (HIGH or LOW). 
+
+	 Do not use when providing values externally
 
      @return HIGH or LOW.
      */