diff --git a/cores/arduino/WInterrupts.cpp b/cores/arduino/WInterrupts.cpp
index 85400142..52769173 100644
--- a/cores/arduino/WInterrupts.cpp
+++ b/cores/arduino/WInterrupts.cpp
@@ -42,32 +42,27 @@ static void __initialize()
 	pmc_enable_periph_clk(ID_PIOA);
 	NVIC_DisableIRQ(PIOA_IRQn);
 	NVIC_ClearPendingIRQ(PIOA_IRQn);
-	NVIC_SetPriority(PIOA_IRQn, pioInterruptPriority);
 	NVIC_EnableIRQ(PIOA_IRQn);
 
 	pmc_enable_periph_clk(ID_PIOB);
 	NVIC_DisableIRQ(PIOB_IRQn);
 	NVIC_ClearPendingIRQ(PIOB_IRQn);
-	NVIC_SetPriority(PIOB_IRQn, pioInterruptPriority);
 	NVIC_EnableIRQ(PIOB_IRQn);
 
 	pmc_enable_periph_clk(ID_PIOC);
 	NVIC_DisableIRQ(PIOC_IRQn);
 	NVIC_ClearPendingIRQ(PIOC_IRQn);
-	NVIC_SetPriority(PIOC_IRQn, pioInterruptPriority);
 	NVIC_EnableIRQ(PIOC_IRQn);
 
 	pmc_enable_periph_clk(ID_PIOD);
 	NVIC_DisableIRQ(PIOD_IRQn);
 	NVIC_ClearPendingIRQ(PIOD_IRQn);
-	NVIC_SetPriority(PIOD_IRQn, pioInterruptPriority);
 	NVIC_EnableIRQ(PIOD_IRQn);
 
 #ifdef ID_PIOE
 	pmc_enable_periph_clk(ID_PIOE);
 	NVIC_DisableIRQ(PIOE_IRQn);
 	NVIC_ClearPendingIRQ(PIOE_IRQn);
-	NVIC_SetPriority(PIOE_IRQn, pioInterruptPriority);
 	NVIC_EnableIRQ(PIOE_IRQn);
 #endif
 }
@@ -76,24 +71,20 @@ static void __initialize()
 // This needs to be fast. Hopefully the ARM conditional instructions will be used to advantage here.
 static unsigned int GetHighestBit(uint32_t bits)
 {
-	unsigned int bitNum = 0;
-	if (bits >= 0x00010000)
-	{
-		bitNum += 16;
-	}
-	if ((bits >> bitNum) >= 0x0100)
+	unsigned int bitNum = (bits >= 0x00010000) ? 16 : 0;
+	if ((bits >> bitNum) >= 0x0100u)
 	{
 		bitNum += 8;
 	}
-	if ((bits >> bitNum) >= 0x0010)
+	if ((bits >> bitNum) >= 0x0010u)
 	{
 		bitNum += 4;
 	}
-	if ((bits >> bitNum) >= 0x0004)
+	if ((bits >> bitNum) >= 0x0004u)
 	{
 		bitNum += 2;
 	}
-	if ((bits >> bitNum) >= 0x0002)
+	if ((bits >> bitNum) >= 0x0002u)
 	{
 		bitNum += 1;
 	}
@@ -102,11 +93,11 @@ static unsigned int GetHighestBit(uint32_t bits)
 
 extern "C" void attachInterrupt(uint32_t pin, void (*callback)(void*), uint32_t mode, void *param)
 {
-	static int enabled = 0;
+	static bool enabled = false;
 	if (!enabled)
 	{
 		__initialize();
-		enabled = 1;
+		enabled = true;
 	}
 
 	// Retrieve pin information
diff --git a/cores/arduino/wiring_digital.cpp b/cores/arduino/wiring_digital.cpp
index d65e6829..6b6b055b 100644
--- a/cores/arduino/wiring_digital.cpp
+++ b/cores/arduino/wiring_digital.cpp
@@ -47,7 +47,7 @@ extern "C" void pinModeDuet(Pin pin, enum PinMode ulMode, uint32_t debounceCutof
 					(debounceCutoff == 0) ? 0 : PIO_DEBOUNCE);
 			if (debounceCutoff != 0)
 			{
-				pio_set_debounce_filter(pinDesc.pPort, pinDesc.ulPin, debounceCutoff);	// enable debounce filer with specified cutoff frequency
+				pio_set_debounce_filter(pinDesc.pPort, pinDesc.ulPin, debounceCutoff);	// enable debounce filter with specified cutoff frequency
 			}
 			break;
 
@@ -64,7 +64,7 @@ extern "C" void pinModeDuet(Pin pin, enum PinMode ulMode, uint32_t debounceCutof
 					(debounceCutoff == 0) ? PIO_PULLUP : PIO_PULLUP | PIO_DEBOUNCE);
 			if (debounceCutoff != 0)
 			{
-				pio_set_debounce_filter(pinDesc.pPort, pinDesc.ulPin, debounceCutoff);	// enable debounce filer with specified cutoff frequency
+				pio_set_debounce_filter(pinDesc.pPort, pinDesc.ulPin, debounceCutoff);	// enable debounce filter with specified cutoff frequency
 			}
 			break;
 
@@ -81,7 +81,7 @@ extern "C" void pinModeDuet(Pin pin, enum PinMode ulMode, uint32_t debounceCutof
 					(debounceCutoff == 0) ? 0 : PIO_DEBOUNCE);
 			if (debounceCutoff != 0)
 			{
-				pio_set_debounce_filter(pinDesc.pPort, pinDesc.ulPin, debounceCutoff);	// enable debounce filer with specified cutoff frequency
+				pio_set_debounce_filter(pinDesc.pPort, pinDesc.ulPin, debounceCutoff);	// enable debounce filter with specified cutoff frequency
 			}
 			break;
 #endif
@@ -154,7 +154,7 @@ extern "C"  void digitalWrite(Pin pin, bool ulVal)
 		const PinDescription& pinDesc = g_APinDescription[pin];
 		if (pinDesc.ulPinType != PIO_NOT_A_PIN)
 		{
-			if (ulVal)		// we make use of the fact that LOW is zero and HIGH is nonzero
+			if (ulVal)
 			{
 				pinDesc.pPort->PIO_SODR = pinDesc.ulPin;
 			}
diff --git a/libraries/RTCDue/RTCDue.cpp b/libraries/RTCDue/RTCDue.cpp
index d072ef55..42bc22f7 100644
--- a/libraries/RTCDue/RTCDue.cpp
+++ b/libraries/RTCDue/RTCDue.cpp
@@ -15,7 +15,6 @@ void RTCDue::Init()
 	// disable RTC alarm interrupts
 	NVIC_DisableIRQ(RTC_IRQn);
 	NVIC_ClearPendingIRQ(RTC_IRQn);
-	NVIC_SetPriority(RTC_IRQn, 8);
 }
 
 bool RTCDue::IsDateTimeSet()
diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp
index 83846096..2ff23193 100644
--- a/libraries/Wire/Wire.cpp
+++ b/libraries/Wire/Wire.cpp
@@ -513,7 +513,6 @@ static void Wire_Init(void) {
 
 	NVIC_DisableIRQ(TWI1_IRQn);
 	NVIC_ClearPendingIRQ(TWI1_IRQn);
-	NVIC_SetPriority(TWI1_IRQn, 6);
 	NVIC_EnableIRQ(TWI1_IRQn);
 }
 
@@ -532,7 +531,6 @@ static void Wire1_Init(void) {
 
 	NVIC_DisableIRQ(TWI0_IRQn);
 	NVIC_ClearPendingIRQ(TWI0_IRQn);
-	NVIC_SetPriority(TWI0_IRQn, 6);
 	NVIC_EnableIRQ(TWI0_IRQn);
 }