diff --git a/Bounce2.cpp b/Bounce2.cpp
index 95a3bc7..aa1aa86 100644
--- a/Bounce2.cpp
+++ b/Bounce2.cpp
@@ -7,9 +7,9 @@
 #endif
 #include "Bounce2.h"
 
-#define DEBOUNCED_STATE 0
-#define UNSTABLE_STATE  1
-#define STATE_CHANGED   3
+static const uint8_t DEBOUNCED_STATE = 0b00000001;
+static const uint8_t UNSTABLE_STATE  = 0b00000010;
+static const uint8_t CHANGED_STATE   = 0b00000100;
 
 
 Bounce::Bounce()
@@ -22,8 +22,8 @@ Bounce::Bounce()
 void Bounce::attach(int pin) {
     this->pin = pin;
     state = 0;
-    if (digitalRead(pin)) {
-        state = _BV(DEBOUNCED_STATE) | _BV(UNSTABLE_STATE);
+    if (readCurrentState()) {
+        setStateFlag(DEBOUNCED_STATE | UNSTABLE_STATE);
     }
 #ifdef BOUNCE_LOCK_OUT
     previous_millis = 0;
@@ -48,27 +48,27 @@ void Bounce::interval(uint16_t interval_millis)
 
 bool Bounce::update()
 {
+
+    unsetStateFlag(CHANGED_STATE);
 #ifdef BOUNCE_LOCK_OUT
-    state &= ~_BV(STATE_CHANGED);
+    
     // Ignore everything if we are locked out
     if (millis() - previous_millis >= interval_millis) {
-        bool currentState = digitalRead(pin);
-        if ((bool)(state & _BV(DEBOUNCED_STATE)) != currentState) {
+        bool currentState = readCurrentState();
+        if ( currentState != getStateFlag(DEBOUNCED_STATE) ) {
             previous_millis = millis();
-            state ^= _BV(DEBOUNCED_STATE);
-            state |= _BV(STATE_CHANGED);
+            toggleStateFlag(DEBOUNCED_STATE);
+            setStateFlag(CHANGED_STATE);
         }
     }
-    return state & _BV(STATE_CHANGED);
+    
 
 #elif defined BOUNCE_WITH_PROMPT_DETECTION
     // Read the state of the switch port into a temporary variable.
-    bool readState = digitalRead(pin);
+    bool readState = readCurrentState();
 
-    // Clear Changed State Flag - will be reset if we confirm a button state change.
-    state &= ~_BV(STATE_CHANGED);
 
-    if ( readState != (bool)(state & _BV(DEBOUNCED_STATE))) {
+    if ( readState != getStateFlag(DEBOUNCED_STATE) ) {
       // We have seen a change from the current button state.
 
       if ( millis() - previous_millis >= interval_millis ) {
@@ -76,55 +76,58 @@ bool Bounce::update()
 	// set the STATE_CHANGED flag and the new DEBOUNCED_STATE.
 	// This will be prompt as long as there has been greater than interval_misllis ms since last change of input.
 	// Otherwise debounced state will not change again until bouncing is stable for the timeout period.
-	state ^= _BV(DEBOUNCED_STATE);
-	state |= _BV(STATE_CHANGED);
+	 toggleStateFlag(DEBOUNCED_STATE);
+     setStateFlag(CHANGED_STATE );
       }
     }
 
     // If the readState is different from previous readState, reset the debounce timer - as input is still unstable
     // and we want to prevent new button state changes until the previous one has remained stable for the timeout.
-    if ( readState != (bool)(state & _BV(UNSTABLE_STATE)) ) {
+    if ( readState != getStateFlag(UNSTABLE_STATE) ) {
 	// Update Unstable Bit to macth readState
-        state ^= _BV(UNSTABLE_STATE);
+        toggleStateFlag(UNSTABLE_STATE);
         previous_millis = millis();
     }
-    // return just the sate changed bit
-    return state & _BV(STATE_CHANGED);
+    
+    
 #else
     // Read the state of the switch in a temporary variable.
-    bool currentState = digitalRead(pin);
-    state &= ~_BV(STATE_CHANGED);
+    bool currentState = readCurrentState();
+    
 
     // If the reading is different from last reading, reset the debounce counter
-    if ( currentState != (bool)(state & _BV(UNSTABLE_STATE)) ) {
+    if ( currentState != getStateFlag(UNSTABLE_STATE) ) {
         previous_millis = millis();
-        state ^= _BV(UNSTABLE_STATE);
+         toggleStateFlag(UNSTABLE_STATE);
     } else
         if ( millis() - previous_millis >= interval_millis ) {
             // We have passed the threshold time, so the input is now stable
             // If it is different from last state, set the STATE_CHANGED flag
-            if ((bool)(state & _BV(DEBOUNCED_STATE)) != currentState) {
+            if (currentState != getStateFlag(DEBOUNCED_STATE) ) {
                 previous_millis = millis();
-                state ^= _BV(DEBOUNCED_STATE);
-                state |= _BV(STATE_CHANGED);
+                 toggleStateFlag(DEBOUNCED_STATE);
+                 setStateFlag(CHANGED_STATE) ;
             }
         }
 
-    return state & _BV(STATE_CHANGED);
+    
 #endif
+
+return  getStateFlag(CHANGED_STATE); 
+
 }
 
 bool Bounce::read()
 {
-    return state & _BV(DEBOUNCED_STATE);
+    return  getStateFlag(DEBOUNCED_STATE);
 }
 
 bool Bounce::rose()
 {
-    return ( state & _BV(DEBOUNCED_STATE) ) && ( state & _BV(STATE_CHANGED));
+    return getStateFlag(DEBOUNCED_STATE) && getStateFlag(CHANGED_STATE);
 }
 
 bool Bounce::fell()
 {
-    return !( state & _BV(DEBOUNCED_STATE) ) && ( state & _BV(STATE_CHANGED));
+    return  !getStateFlag(DEBOUNCED_STATE) && getStateFlag(CHANGED_STATE);
 }
diff --git a/Bounce2.h b/Bounce2.h
index 92200fe..fa6a28a 100644
--- a/Bounce2.h
+++ b/Bounce2.h
@@ -37,9 +37,11 @@
 
 #include <inttypes.h>
 
+/*
 #ifndef _BV
 #define _BV(n) (1<<(n))
 #endif
+*/
 
 class Bounce
 {
@@ -83,6 +85,13 @@ class Bounce
     uint16_t interval_millis;
     uint8_t state;
     uint8_t pin;
+    virtual bool readCurrentState() { return digitalRead(pin); }
+
+  private:
+    inline void setStateFlag(const uint8_t flag)    {state |= flag;}
+    inline void unsetStateFlag(const uint8_t flag)  {state &= ~flag;}
+    inline void toggleStateFlag(const uint8_t flag) {state ^= flag;}
+    inline bool getStateFlag(const uint8_t flag)    {return((state & flag) != 0);}
 };
 
 #endif