diff --git a/library.properties b/library.properties
index 2c30a06..630f2cd 100755
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=uClock
-version=0.9.0
+version=0.9.1
 author=Romulo Silva <contact@midilab.co>, Manuel Odendahl <wesen@ruinwesen.com>
 maintainer=Romulo Silva <contact@midilab.co>
 sentence=BPM clock generator for Arduino and Teensy boards
diff --git a/src/uClock.cpp b/src/uClock.cpp
index a91c477..2641dcd 100755
--- a/src/uClock.cpp
+++ b/src/uClock.cpp
@@ -34,7 +34,7 @@
 // Timer setup
 // Work clock at: 62.5kHz/16usec
 //
-#if defined(TEENSYDUINO)
+#if defined(TEENSYDUINO) && !defined(__AVR_ATmega32U4__)
 IntervalTimer _teensyTimer;
 void teensyInterrupt();
 void initTeensyTimer()
@@ -73,7 +73,7 @@ void initArduinoTimer()
 #endif
 
 void initWorkTimer() {
-#if defined(TEENSYDUINO)
+#if defined(TEENSYDUINO) && !defined(__AVR_ATmega32U4__)
 	initTeensyTimer();
 #else
 	initArduinoTimer();
@@ -104,6 +104,8 @@ uClockClass::uClockClass()
 	drift = 11;
 	pll_x = 220;
 	start_timer = 0;
+	last_interval = 0;
+	sync_interval = 0;
 	state = PAUSED;
 	mode = INTERNAL_CLOCK;
 	resetCounters();
@@ -240,11 +242,9 @@ void uClockClass::shuffle()
 
 void uClockClass::handleExternalClock() 
 {
-	uint16_t cur_clock = _clock;
-	uint16_t diff = clock_diff(last_clock, cur_clock);
-	
-	last_interval = diff;
-	last_clock = cur_clock;
+	last_interval = clock_diff(last_clock, _clock);
+	last_clock = _clock;
+
 	indiv96th_counter++;
 	inmod6_counter++;
 
@@ -263,9 +263,9 @@ void uClockClass::handleExternalClock()
 
 		case STARTED:
 			if (indiv96th_counter == 2) {
-				interval = diff;
+				interval = last_interval;
 			} else {
-				interval = (((uint32_t)interval * (uint32_t)pll_x) + (uint32_t)(256 - pll_x) * (uint32_t)diff) >> 8;
+				interval = (((uint32_t)interval * (uint32_t)pll_x) + (uint32_t)(256 - pll_x) * (uint32_t)last_interval) >> 8;
 			}
 			break;
 	}
@@ -303,17 +303,16 @@ void uClockClass::handleTimerInt()
 		mod6_counter++;
 	
 		if (mode == EXTERNAL_CLOCK) {
-			uint16_t cur_clock = _clock;
-			uint16_t diff = clock_diff(last_clock, cur_clock);
+			sync_interval = clock_diff(last_clock, _clock);
 			if ((div96th_counter < indiv96th_counter) || (div96th_counter > (indiv96th_counter + 1))) {
 				div96th_counter = indiv96th_counter;
 				mod6_counter = inmod6_counter;
 			}
 			if (div96th_counter <= indiv96th_counter) {
-				counter -= phase_mult(diff);
+				counter -= phase_mult(sync_interval);
 			} else {
-				if (counter > diff) {
-					counter += phase_mult(counter - diff);
+				if (counter > sync_interval) {
+					counter += phase_mult(counter - sync_interval);
 				}
 			}
 		}
@@ -382,7 +381,7 @@ volatile uint32_t _timer = 0;
 // TIMER INTERRUPT HANDLER 
 // Clocked at: 62.5kHz/16usec
 //
-#if defined(TEENSYDUINO)
+#if defined(TEENSYDUINO) && !defined(__AVR_ATmega32U4__)
 void teensyInterrupt() 
 #else
 ISR(TIMER1_OVF_vect) 
diff --git a/src/uClock.h b/src/uClock.h
index 8944478..20fa059 100755
--- a/src/uClock.h
+++ b/src/uClock.h
@@ -62,22 +62,26 @@ class uClockClass {
 		void (*onClockStartCallback)();
 		void (*onClockStopCallback)();
 
+		volatile uint8_t inmod6_counter;
+		volatile uint32_t indiv96th_counter;
+		volatile uint16_t interval;
+		volatile uint16_t last_clock;
+		
 		uint32_t div96th_counter;
 		uint32_t div32th_counter;
 		uint32_t div16th_counter;
 		uint8_t mod6_counter;
-		uint8_t inmod6_counter;
-		volatile uint16_t interval;
 		uint16_t counter;
-		uint16_t last_clock;
-		uint16_t last_interval;
-		uint32_t indiv96th_counter;
+
 		uint16_t pll_x;
 		uint8_t drift;
 		uint16_t tempo;
 		uint32_t start_timer;
 		uint8_t mode;
 	
+		uint16_t last_interval;
+		uint16_t sync_interval;
+
 	public:
 
 		uint8_t state;