diff --git a/hardware/arduino/sam/cores/arduino/USB/CDC.cpp b/hardware/arduino/sam/cores/arduino/USB/CDC.cpp
index 8992a2e63..e7c12573a 100644
--- a/hardware/arduino/sam/cores/arduino/USB/CDC.cpp
+++ b/hardware/arduino/sam/cores/arduino/USB/CDC.cpp
@@ -23,6 +23,7 @@
 
 #define CDC_SERIAL_BUFFER_SIZE	64
 
+/* For information purpose only since RTS is not always handled by the terminal application */
 #define CDC_LINESTATE_DTR		0x01 // Data Terminal Ready
 #define CDC_LINESTATE_RTS		0x02 // Ready to Send
 
@@ -211,7 +212,7 @@ size_t Serial_::write(uint8_t c)
 	// TODO - ZE - check behavior on different OSes and test what happens if an
 	// open connection isn't broken cleanly (cable is yanked out, host dies
 	// or locks up, or host virtual serial port hangs)
-	if (_usbLineInfo.lineState == CDC_LINESTATE_READY)
+	if (_usbLineInfo.lineState > 0)
 	{
 		int r = USBD_Send(CDC_TX,&c,1);
 
@@ -240,7 +241,7 @@ Serial_::operator bool()
 {
 	bool result = false;
 
-	if (_usbLineInfo.lineState == CDC_LINESTATE_READY)
+	if (_usbLineInfo.lineState > 0)
 	{
 		result = true;
 	}
diff --git a/hardware/arduino/sam/cores/arduino/USB/HID.cpp b/hardware/arduino/sam/cores/arduino/USB/HID.cpp
index a02dbec8c..cb8336b3c 100644
--- a/hardware/arduino/sam/cores/arduino/USB/HID.cpp
+++ b/hardware/arduino/sam/cores/arduino/USB/HID.cpp
@@ -503,9 +503,12 @@ void Keyboard_::releaseAll(void)
 
 size_t Keyboard_::write(uint8_t c)
 {
-	uint8_t p = press(c);		// Keydown
-	uint8_t r = release(c);		// Keyup
-	return (p);					// just return the result of press() since release() almost always returns 1
+	uint8_t p = 0;
+
+	p = press(c);	// Keydown
+	release(c);		// Keyup
+
+	return (p);		// Just return the result of press() since release() almost always returns 1
 }
 
 #endif
diff --git a/hardware/arduino/sam/cores/arduino/USB/USBCore.cpp b/hardware/arduino/sam/cores/arduino/USB/USBCore.cpp
index da920a675..009e952bd 100644
--- a/hardware/arduino/sam/cores/arduino/USB/USBCore.cpp
+++ b/hardware/arduino/sam/cores/arduino/USB/USBCore.cpp
@@ -1,5 +1,5 @@
-/* Copyright (c) 2010, Peter Barrett
-**
+// Copyright (c) 2010, Peter Barrett
+/*
 ** Permission to use, copy, modify, and/or distribute this software for
 ** any purpose with or without fee is hereby granted, provided that the
 ** above copyright notice and this permission notice appear in all copies.
@@ -44,11 +44,11 @@ volatile uint8_t RxLEDPulse; /**< Milliseconds remaining for data Rx LED pulse *
 //==================================================================
 //==================================================================
 
-extern const uint16_t STRING_LANGUAGE[] ;
-extern const uint16_t STRING_IPRODUCT[] ;
-extern const uint16_t STRING_IMANUFACTURER[] ;
-extern const DeviceDescriptor USB_DeviceDescriptor ;
-extern const DeviceDescriptor USB_DeviceDescriptorA ;
+extern const uint16_t STRING_LANGUAGE[];
+extern const uint16_t STRING_IPRODUCT[];
+extern const uint16_t STRING_IMANUFACTURER[];
+extern const DeviceDescriptor USB_DeviceDescriptor;
+extern const DeviceDescriptor USB_DeviceDescriptorA;
 
 const uint16_t STRING_LANGUAGE[2] = {
 	(3<<8) | (2+2),
@@ -86,8 +86,6 @@ const DeviceDescriptor USB_DeviceDescriptor =
 const DeviceDescriptor USB_DeviceDescriptorA =
 	D_DEVICE(DEVICE_CLASS,0x00,0x00,64,USB_VID,USB_PID,0x100,IMANUFACTURER,IPRODUCT,0,1);
 
-
-
 //==================================================================
 //==================================================================
 
@@ -233,11 +231,11 @@ int USBD_SendControl(uint8_t flags, const void* d, uint32_t len)
 //	TODO
 int USBD_RecvControl(void* d, uint32_t len)
 {
-	UDD_WaitOUT() ;
-	UDD_Recv(EP0, (uint8_t*)d, len ) ;
-	UDD_ClearOUT() ;
+	UDD_WaitOUT();
+	UDD_Recv(EP0, (uint8_t*)d, len);
+	UDD_ClearOUT();
 
-	return len ;
+	return len;
 }
 
 //	Handle CLASS_INTERFACE requests
@@ -248,20 +246,20 @@ bool USBD_ClassInterfaceRequest(Setup& setup)
 	TRACE_CORE(printf("=> USBD_ClassInterfaceRequest\r\n");)
 
 #ifdef CDC_ENABLED
-	if ( CDC_ACM_INTERFACE == i )
+	if (CDC_ACM_INTERFACE == i)
 	{
 		return CDC_Setup(setup);
 	}
 #endif
 
 #ifdef HID_ENABLED
-	if ( HID_INTERFACE == i )
+	if (HID_INTERFACE == i)
 	{
 		return HID_Setup(setup);
 	}
 #endif
 
-	return false ;
+	return false;
 }
 
 int USBD_SendInterfaces(void)
@@ -270,11 +268,11 @@ int USBD_SendInterfaces(void)
 	uint8_t interfaces = 0;
 
 #ifdef CDC_ENABLED
-	total = CDC_GetInterface(&interfaces) ;
+	total = CDC_GetInterface(&interfaces);
 #endif
 
 #ifdef HID_ENABLED
-	total += HID_GetInterface(&interfaces) ;
+	total += HID_GetInterface(&interfaces);
 #endif
 
 	total = total; // Get rid of compiler warning
@@ -314,7 +312,7 @@ static bool USBD_SendDescriptor(Setup& setup)
 	uint8_t desc_length = 0;
 	const uint8_t* desc_addr = 0;
 
-	if ( USB_CONFIGURATION_DESCRIPTOR_TYPE == t )
+	if (USB_CONFIGURATION_DESCRIPTOR_TYPE == t)
 	{
 		TRACE_CORE(printf("=> USBD_SendDescriptor : USB_CONFIGURATION_DESCRIPTOR_TYPE length=%d\r\n", setup.wLength);)
 		return USBD_SendConfiguration(setup.wLength);
@@ -322,17 +320,17 @@ static bool USBD_SendDescriptor(Setup& setup)
 
 	USBD_InitControl(setup.wLength);
 #ifdef HID_ENABLED
-	if ( HID_REPORT_DESCRIPTOR_TYPE == t )
+	if (HID_REPORT_DESCRIPTOR_TYPE == t)
 	{
 		TRACE_CORE(puts("=> USBD_SendDescriptor : HID_REPORT_DESCRIPTOR_TYPE\r\n");)
-		return HID_GetDescriptor( t ) ;
+		return HID_GetDescriptor(t);
 	}
 #endif
 
 	if (USB_DEVICE_DESCRIPTOR_TYPE == t)
 	{
 		TRACE_CORE(puts("=> USBD_SendDescriptor : USB_DEVICE_DESCRIPTOR_TYPE\r\n");)
-		if ( setup.wLength == 8 )
+		if (setup.wLength == 8)
 		{
 			_cdcComposite = 1;
 		}
@@ -351,17 +349,17 @@ static bool USBD_SendDescriptor(Setup& setup)
 			return false;
 	}
 
-	if ( desc_addr == 0 )
+	if (desc_addr == 0)
 	{
-		return false ;
+		return false;
 	}
 
-	if ( desc_length == 0 )
+	if (desc_length == 0)
 	{
 		desc_length = *desc_addr;
 	}
 
-	TRACE_CORE(printf("=> USBD_SendDescriptor : desc_addr=%x desc_length=%d\r\n", desc_addr, desc_length);)
+	TRACE_CORE(printf("=> USBD_SendDescriptor : desc_addr=%p desc_length=%d\r\n", desc_addr, desc_length);)
 	USBD_SendControl(0, desc_addr, desc_length);
 
 	return true;
@@ -397,7 +395,7 @@ static void USB_ISR(void)
 		while (USBD_Available(CDC_RX))
 			Serial.accept();
 
-		udd_ack_fifocon(CDC_RX) ;
+		udd_ack_fifocon(CDC_RX);
 	}
 #endif
 
@@ -405,12 +403,12 @@ static void USB_ISR(void)
 	if (Is_udd_endpoint_interrupt(0))
 	{
 
-		if ( !UDD_ReceivedSetupInt() )
+		if (!UDD_ReceivedSetupInt())
 		{
 			return;
 		}
 
-		Setup setup ;
+		Setup setup;
 		UDD_Recv(EP0, (uint8_t*)&setup, 8);
 		UDD_ClearSetupInt();
 
@@ -426,7 +424,7 @@ static void USB_ISR(void)
 			UDD_ClearIN();
 		}
 
-		bool ok = true ;
+		bool ok = true;
 		if (REQUEST_STANDARD == (requestType & REQUEST_TYPE))
 		{
 			// Standard Requests
@@ -544,36 +542,36 @@ USBDevice_::USBDevice_()
 {
 	UDD_SetStack(&USB_ISR);
 
-	if ( UDD_Init() == 0UL )
+	if (UDD_Init() == 0UL)
 	{
-		_usbInitialized=1UL ;
+		_usbInitialized=1UL;
 	}
 }
 
 bool USBDevice_::attach(void)
 {
-  if ( _usbInitialized != 0UL )
+  if (_usbInitialized != 0UL)
   {
-    UDD_Attach() ;
+    UDD_Attach();
 	_usbConfiguration = 0;
 	return true;
   }
   else
   {
-    return false ;
+    return false;
   }
 }
 
 bool USBDevice_::detach(void)
 {
-	if ( _usbInitialized != 0UL )
+	if (_usbInitialized != 0UL)
 	{
-		UDD_Detach() ;
-		return true ;
+		UDD_Detach();
+		return true;
 	}
 	else
 	{
-		return false ;
+		return false;
 	}
 }
 
diff --git a/hardware/arduino/sam/cores/arduino/USB/USBCore.h b/hardware/arduino/sam/cores/arduino/USB/USBCore.h
index 68b18ff65..ef77bd9de 100644
--- a/hardware/arduino/sam/cores/arduino/USB/USBCore.h
+++ b/hardware/arduino/sam/cores/arduino/USB/USBCore.h
@@ -1,4 +1,3 @@
-
 // Copyright (c) 2010, Peter Barrett
 /*
 ** Permission to use, copy, modify, and/or distribute this software for
@@ -19,33 +18,33 @@
 #define __USBCORE_H__
 
 //	Standard requests
-#define GET_STATUS			0
-#define CLEAR_FEATURE		1
-#define SET_FEATURE			3
-#define SET_ADDRESS			5
-#define GET_DESCRIPTOR		6
-#define SET_DESCRIPTOR		7
-#define GET_CONFIGURATION	8
-#define SET_CONFIGURATION	9
-#define GET_INTERFACE		10
-#define SET_INTERFACE		11
+#define GET_STATUS					0
+#define CLEAR_FEATURE				1
+#define SET_FEATURE					3
+#define SET_ADDRESS					5
+#define GET_DESCRIPTOR				6
+#define SET_DESCRIPTOR				7
+#define GET_CONFIGURATION			8
+#define SET_CONFIGURATION			9
+#define GET_INTERFACE				10
+#define SET_INTERFACE				11
 
 
 // bmRequestType
-#define REQUEST_HOSTTODEVICE	0x00
-#define REQUEST_DEVICETOHOST	0x80
-#define REQUEST_DIRECTION		0x80
+#define REQUEST_HOSTTODEVICE		0x00
+#define REQUEST_DEVICETOHOST		0x80
+#define REQUEST_DIRECTION			0x80
 
-#define REQUEST_STANDARD		0x00
-#define REQUEST_CLASS			0x20
-#define REQUEST_VENDOR			0x40
-#define REQUEST_TYPE			0x60
+#define REQUEST_STANDARD			0x00
+#define REQUEST_CLASS				0x20
+#define REQUEST_VENDOR				0x40
+#define REQUEST_TYPE				0x60
 
-#define REQUEST_DEVICE			0x00
-#define REQUEST_INTERFACE		0x01
-#define REQUEST_ENDPOINT		0x02
-#define REQUEST_OTHER			0x03
-#define REQUEST_RECIPIENT		0x1F
+#define REQUEST_DEVICE				0x00
+#define REQUEST_INTERFACE			0x01
+#define REQUEST_ENDPOINT			0x02
+#define REQUEST_OTHER				0x03
+#define REQUEST_RECIPIENT			0x1F
 
 #define REQUEST_DEVICETOHOST_CLASS_INTERFACE  (REQUEST_DEVICETOHOST + REQUEST_CLASS + REQUEST_INTERFACE)
 #define REQUEST_HOSTTODEVICE_CLASS_INTERFACE  (REQUEST_HOSTTODEVICE + REQUEST_CLASS + REQUEST_INTERFACE)
@@ -129,12 +128,12 @@ _Pragma("pack(1)")
 //	Device
 typedef struct {
 	uint8_t len;				// 18
-	uint8_t dtype;			// 1 USB_DEVICE_DESCRIPTOR_TYPE
+	uint8_t dtype;				// 1 USB_DEVICE_DESCRIPTOR_TYPE
 	uint16_t usbVersion;		// 0x200
 	uint8_t	deviceClass;
 	uint8_t	deviceSubClass;
 	uint8_t	deviceProtocol;
-	uint8_t	packetSize0;	// Packet 0
+	uint8_t	packetSize0;		// Packet 0
 	uint16_t	idVendor;
 	uint16_t	idProduct;
 	uint16_t	deviceVersion;	// 0x100
@@ -162,7 +161,7 @@ typedef struct {
 typedef struct
 {
 	uint8_t len;		// 9
-	uint8_t dtype;	// 4
+	uint8_t dtype;		// 4
 	uint8_t number;
 	uint8_t alternate;
 	uint8_t numEndpoints;
@@ -176,7 +175,7 @@ typedef struct
 typedef struct
 {
 	uint8_t len;		// 7
-	uint8_t dtype;	// 5
+	uint8_t dtype;		// 5
 	uint8_t addr;
 	uint8_t attr;
 	uint16_t packetSize;
@@ -188,7 +187,7 @@ typedef struct
 typedef struct
 {
 	uint8_t len;				// 8
-	uint8_t dtype;			// 11
+	uint8_t dtype;				// 11
 	uint8_t firstInterface;
 	uint8_t interfaceCount;
 	uint8_t functionClass;
@@ -201,7 +200,7 @@ typedef struct
 typedef struct
 {
 	uint8_t len;		// 5
-	uint8_t dtype;	// 0x24
+	uint8_t dtype;		// 0x24
 	uint8_t subtype;
 	uint8_t d0;
 	uint8_t d1;
@@ -210,7 +209,7 @@ typedef struct
 typedef struct
 {
 	uint8_t len;		// 4
-	uint8_t dtype;	// 0x24
+	uint8_t dtype;		// 0x24
 	uint8_t subtype;
 	uint8_t d0;
 } CDCCSInterfaceDescriptor4;
@@ -238,7 +237,7 @@ typedef struct
 	IADDescriptor				iad;	// Only needed on compound device
 
 	//	Control
-	InterfaceDescriptor			cif;	//
+	InterfaceDescriptor			cif;
 	CDCCSInterfaceDescriptor	header;
 	CMFunctionalDescriptor		callManagement;			// Call Management
 	ACMFunctionalDescriptor		controlManagement;		// ACM
@@ -261,21 +260,21 @@ typedef struct
 typedef struct
 {
 	uint8_t len;			// 9
-	uint8_t dtype;		// 0x21
+	uint8_t dtype;			// 0x21
 	uint8_t addr;
-	uint8_t	versionL;	// 0x101
-	uint8_t	versionH;	// 0x101
+	uint8_t	versionL;		// 0x101
+	uint8_t	versionH;		// 0x101
 	uint8_t	country;
-	uint8_t	desctype;	// 0x22 report
+	uint8_t	desctype;		// 0x22 report
 	uint8_t	descLenL;
 	uint8_t	descLenH;
 } HIDDescDescriptor;
 
 typedef struct
 {
-	InterfaceDescriptor			hid;
-	HIDDescDescriptor			desc;
-	EndpointDescriptor			in;
+	InterfaceDescriptor		hid;
+	HIDDescDescriptor		desc;
+	EndpointDescriptor		in;
 } HIDDescriptor;
 
 _Pragma("pack()")
diff --git a/hardware/arduino/sam/cores/arduino/USB/USBDesc.h b/hardware/arduino/sam/cores/arduino/USB/USBDesc.h
index fb5895adf..878095e24 100644
--- a/hardware/arduino/sam/cores/arduino/USB/USBDesc.h
+++ b/hardware/arduino/sam/cores/arduino/USB/USBDesc.h
@@ -1,7 +1,5 @@
-
-
-/* Copyright (c) 2011, Peter Barrett
-**
+// Copyright (c) 2010, Peter Barrett
+/*
 ** Permission to use, copy, modify, and/or distribute this software for
 ** any purpose with or without fee is hereby granted, provided that the
 ** above copyright notice and this permission notice appear in all copies.
@@ -16,10 +14,12 @@
 ** SOFTWARE.
 */
 
+#ifndef __USBDESC_H__
+#define __USBDESC_H__
+
 #define CDC_ENABLED
 #define HID_ENABLED
 
-
 #ifdef CDC_ENABLED
 #define CDC_INTERFACE_COUNT	2
 #define CDC_ENPOINT_COUNT	3
@@ -39,11 +39,11 @@
 #define CDC_ACM_INTERFACE	0	// CDC ACM
 #define CDC_DATA_INTERFACE	1	// CDC Data
 #define CDC_FIRST_ENDPOINT	1
-#define CDC_ENDPOINT_ACM	(CDC_FIRST_ENDPOINT)							// CDC First
+#define CDC_ENDPOINT_ACM	(CDC_FIRST_ENDPOINT)						// CDC First
 #define CDC_ENDPOINT_OUT	(CDC_FIRST_ENDPOINT+1)
 #define CDC_ENDPOINT_IN		(CDC_FIRST_ENDPOINT+2)
 
-#define HID_INTERFACE		(CDC_ACM_INTERFACE + CDC_INTERFACE_COUNT)		// HID Interface
+#define HID_INTERFACE		(CDC_ACM_INTERFACE + CDC_INTERFACE_COUNT)	// HID Interface
 #define HID_FIRST_ENDPOINT	(CDC_FIRST_ENDPOINT + CDC_ENPOINT_COUNT)
 #define HID_ENDPOINT_INT	(HID_FIRST_ENDPOINT)
 
@@ -61,3 +61,4 @@
 #define IMANUFACTURER	1
 #define IPRODUCT		2
 
+#endif /* __USBDESC_H__ */
diff --git a/hardware/arduino/sam/cores/arduino/validation_usb_device/test_usb_device.cpp b/hardware/arduino/sam/cores/arduino/validation_usb_device/test_usb_device.cpp
index ebb27d07b..af43364c0 100644
--- a/hardware/arduino/sam/cores/arduino/validation_usb_device/test_usb_device.cpp
+++ b/hardware/arduino/sam/cores/arduino/validation_usb_device/test_usb_device.cpp
@@ -25,7 +25,6 @@ void setup() {
 }
 
 void loop() {
-
 	Mouse.move(1, 0, 0);
 
 	if (Serial.available() > 0)
diff --git a/hardware/arduino/sam/system/libsam/include/USB_device.h b/hardware/arduino/sam/system/libsam/include/USB_device.h
index 816b8bf17..a8d980a66 100644
--- a/hardware/arduino/sam/system/libsam/include/USB_device.h
+++ b/hardware/arduino/sam/system/libsam/include/USB_device.h
@@ -21,49 +21,35 @@
 
 #include <stdint.h>
 
-extern void UDD_WaitIN(void) ;
-extern void UDD_WaitOUT(void) ;
-extern void UDD_ClearIN(void) ;
-extern void UDD_ClearOUT(void) ;
-extern uint32_t UDD_WaitForINOrOUT(void) ;
-
-extern void UDD_ClearRxFlag( unsigned char bEndpoint ) ;
-
-
+extern void UDD_WaitIN(void);
+extern void UDD_WaitOUT(void);
+extern void UDD_ClearIN(void);
+extern void UDD_ClearOUT(void);
+extern uint32_t UDD_WaitForINOrOUT(void);
+extern void UDD_ClearRxFlag(unsigned char bEndpoint);
 extern uint32_t UDD_ReceivedSetupInt(void);
 extern void UDD_ClearSetupInt(void);
-
-extern uint32_t UDD_ReadWriteAllowed(uint32_t ep) ;
-
-
-extern uint32_t UDD_FifoByteCount(uint32_t ep) ;
-extern uint8_t UDD_FifoFree(void) ;
-
-extern void UDD_ReleaseRX(uint32_t ep) ;
-extern void UDD_ReleaseTX(uint32_t ep) ;
-extern uint8_t UDD_FrameNumber(void) ;
-
-extern uint8_t UDD_GetConfiguration(void) ;
-
-
-
+extern uint32_t UDD_ReadWriteAllowed(uint32_t ep);
+extern uint32_t UDD_FifoByteCount(uint32_t ep);
+extern uint8_t UDD_FifoFree(void);
+extern void UDD_ReleaseRX(uint32_t ep);
+extern void UDD_ReleaseTX(uint32_t ep);
+extern uint8_t UDD_FrameNumber(void);
+extern uint8_t UDD_GetConfiguration(void);
 
 extern uint32_t UDD_Send(uint32_t ep, const void* data, uint32_t len);
 extern void UDD_Send8(uint32_t ep,  uint8_t data );
 extern uint8_t UDD_Recv8(uint32_t ep);
 extern void UDD_Recv(uint32_t ep, uint8_t* data, uint32_t len);
 
-
-
 extern void UDD_InitEndpoints(const uint32_t* eps_table, const uint32_t ul_eps_table_size);
-
-extern void UDD_InitControl(int end) ;
-
-extern uint32_t UDD_Init(void) ;
+extern void UDD_InitControl(int end);
+extern uint32_t UDD_Init(void);
 extern void UDD_InitEP( uint32_t ul_ep, uint32_t ul_ep_cfg );
 
-extern void UDD_Attach(void) ;
-extern void UDD_Detach(void) ;
+extern void UDD_Attach(void);
+extern void UDD_Detach(void);
+
 extern void UDD_SetStack(void (*pf_isr)(void));
 extern void UDD_SetAddress(uint32_t addr);
 extern void UDD_Stall(void);
@@ -80,8 +66,8 @@ typedef unsigned char           Bool; //!< Boolean.
 typedef unsigned char           bool; //!< Boolean.
 #endif
 #endif
-typedef int8_t                  S8 ;  //!< 8-bit signed integer.
-typedef uint8_t                 U8 ;  //!< 8-bit unsigned integer.
+typedef int8_t                  S8;  //!< 8-bit signed integer.
+typedef uint8_t                 U8;  //!< 8-bit unsigned integer.
 typedef int16_t                 S16;  //!< 16-bit signed integer.
 typedef uint16_t                U16;  //!< 16-bit unsigned integer.
 typedef uint16_t                le16_t;