diff --git a/hardware/keyboardio/cores/keyboardio/HID.cpp b/hardware/keyboardio/cores/keyboardio/HID.cpp
index f216a85e..84870c0a 100644
--- a/hardware/keyboardio/cores/keyboardio/HID.cpp
+++ b/hardware/keyboardio/cores/keyboardio/HID.cpp
@@ -90,6 +90,7 @@ const u8 _hidReportDescriptor[] = {
     0x85, HID_REPORTID_KEYBOARD,                    //   REPORT_ID (2)
     0x05, 0x07,                    //   USAGE_PAGE (Keyboard)
 
+    // Keyboard Modifiers (shift, alt, ...)
     0x19, 0xe0,                    //   USAGE_MINIMUM (Keyboard LeftControl)
     0x29, 0xe7,                    //   USAGE_MAXIMUM (Keyboard Right GUI)
     0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
@@ -102,14 +103,14 @@ const u8 _hidReportDescriptor[] = {
     0x75, 0x08,                    //   REPORT_SIZE (8)
     0x81, 0x03,                    //   INPUT (Cnst,Var,Abs)
 
+    // Keyboard keys
     0x95, 0x06,                    //   REPORT_COUNT (6)
     0x75, 0x08,                    //   REPORT_SIZE (8)
     0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
-    0x25, 0x65,                    //   LOGICAL_MAXIMUM (101)
+    0x26, 0xDF, 0x00,              //   LOGICAL_MAXIMUM (239)
     0x05, 0x07,                    //   USAGE_PAGE (Keyboard)
-    
     0x19, 0x00,                    //   USAGE_MINIMUM (Reserved (no event indicated))
-    0x29, 0x65,                    //   USAGE_MAXIMUM (Keyboard Application)
+    0x29, 0xDF,                    //   USAGE_MAXIMUM (Left Control - 1)
     0x81, 0x00,                    //   INPUT (Data,Ary,Abs)
     0xc0,                          // END_COLLECTION
 
@@ -571,9 +572,33 @@ uint8_t USBPutChar(uint8_t c);
 // to the persistent key report and sends the report.  Because of the way 
 // USB HID works, the host acts like the key remains pressed until we 
 // call release(), releaseAll(), or otherwise clear the report and resend.
-size_t Keyboard_::press(uint8_t k) 
+size_t Keyboard_::pressRaw(uint8_t k) 
 {
 	uint8_t i;
+	// Add k to the key report only if it's not already present
+	// and if there is an empty slot.
+	if (_keyReport.keys[0] != k && _keyReport.keys[1] != k && 
+		_keyReport.keys[2] != k && _keyReport.keys[3] != k &&
+		_keyReport.keys[4] != k && _keyReport.keys[5] != k) {
+		
+		for (i=0; i<6; i++) {
+			if (_keyReport.keys[i] == 0x00) {
+				_keyReport.keys[i] = k;
+				break;
+			}
+		}
+		if (i == 6 || (k >= 0xE0)) {
+			setWriteError();
+			return 0;
+		}	
+	}
+	sendReport(&_keyReport);
+	return 1;
+}
+
+// translates ASCII characters to usage
+size_t Keyboard_::press(uint8_t k) 
+{
 	if (k >= 136) {			// it's a non-printing key (not a modifier)
 		k = k - 136;
 	} else if (k >= 128) {	// it's a modifier key
@@ -590,28 +615,48 @@ size_t Keyboard_::press(uint8_t k)
 			k &= 0x7F;
 		}
 	}
-	
-	// Add k to the key report only if it's not already present
-	// and if there is an empty slot.
-	if (_keyReport.keys[0] != k && _keyReport.keys[1] != k && 
-		_keyReport.keys[2] != k && _keyReport.keys[3] != k &&
-		_keyReport.keys[4] != k && _keyReport.keys[5] != k) {
-		
-		for (i=0; i<6; i++) {
-			if (_keyReport.keys[i] == 0x00) {
-				_keyReport.keys[i] = k;
-				break;
-			}
+	return pressRaw(k);
+}
+
+// release() takes the specified key out of the persistent key report and
+// sends the report.  This tells the OS the key is no longer pressed and that
+// it shouldn't be repeated any more.
+size_t Keyboard_::releaseRaw(uint8_t k) 
+{
+	uint8_t i;
+	// Test the key report to see if k is present.  Clear it if it exists.
+	// Check all positions in case the key is present more than once (which it shouldn't be)
+	for (i=0; i<6; i++) {
+		if (0 != k && _keyReport.keys[i] == k) {
+			_keyReport.keys[i] = 0x00;
 		}
-		if (i == 6) {
-			setWriteError();
-			return 0;
-		}	
 	}
+
 	sendReport(&_keyReport);
 	return 1;
 }
 
+// translates ASCII characters to usage
+size_t Keyboard_::release(uint8_t k) 
+{
+	if (k >= 136) {			// it's a non-printing key (not a modifier)
+		k = k - 136;
+	} else if (k >= 128) {	// it's a modifier key
+		_keyReport.modifiers &= ~(1<<(k-128));
+		k = 0;
+	} else {				// it's a printing key
+		k = pgm_read_byte(_asciimap + k);
+		if (!k) {
+			return 0;
+		}
+		if (k & 0x80) {							// it's a capital letter or other character reached with shift
+			_keyReport.modifiers &= ~(0x02);	// the left shift modifier
+			k &= 0x7F;
+		}
+	}
+	return releaseRaw(k);
+}
+
 // System Control
 //  k is one of the SYSTEM_CONTROL defines which come from the HID usage table "Generic Desktop Page (0x01)"
 // in "HID Usage Tables" (HUT1_12v2.pdf)
@@ -644,40 +689,6 @@ size_t Keyboard_::systemControl(uint8_t k)
 	}
 }
 
-// release() takes the specified key out of the persistent key report and
-// sends the report.  This tells the OS the key is no longer pressed and that
-// it shouldn't be repeated any more.
-size_t Keyboard_::release(uint8_t k) 
-{
-	uint8_t i;
-	if (k >= 136) {			// it's a non-printing key (not a modifier)
-		k = k - 136;
-	} else if (k >= 128) {	// it's a modifier key
-		_keyReport.modifiers &= ~(1<<(k-128));
-		k = 0;
-	} else {				// it's a printing key
-		k = pgm_read_byte(_asciimap + k);
-		if (!k) {
-			return 0;
-		}
-		if (k & 0x80) {							// it's a capital letter or other character reached with shift
-			_keyReport.modifiers &= ~(0x02);	// the left shift modifier
-			k &= 0x7F;
-		}
-	}
-	
-	// Test the key report to see if k is present.  Clear it if it exists.
-	// Check all positions in case the key is present more than once (which it shouldn't be)
-	for (i=0; i<6; i++) {
-		if (0 != k && _keyReport.keys[i] == k) {
-			_keyReport.keys[i] = 0x00;
-		}
-	}
-
-	sendReport(&_keyReport);
-	return 1;
-}
-
 void Keyboard_::releaseAll(void)
 {
 	_keyReport.keys[0] = 0;
@@ -690,10 +701,17 @@ void Keyboard_::releaseAll(void)
 	sendReport(&_keyReport);
 }
 
+size_t Keyboard_::writeRaw(uint8_t c)
+{	
+	uint8_t p = pressRaw(c);		// Keydown
+	releaseRaw(c);		// Keyup
+	return (p);				// just return the result of press() since release() almost always returns 1
+}
+
 size_t Keyboard_::write(uint8_t c)
 {	
 	uint8_t p = press(c);		// Keydown
-	uint8_t r = release(c);		// Keyup
+	release(c);		// Keyup
 	return (p);					// just return the result of press() since release() almost always returns 1
 }
 
diff --git a/hardware/keyboardio/cores/keyboardio/USBAPI.h b/hardware/keyboardio/cores/keyboardio/USBAPI.h
index bd205097..2a6d72b8 100644
--- a/hardware/keyboardio/cores/keyboardio/USBAPI.h
+++ b/hardware/keyboardio/cores/keyboardio/USBAPI.h
@@ -155,8 +155,11 @@ public:
 	void begin(void);
 	void end(void);
 	virtual size_t write(uint8_t k);
+	virtual size_t writeRaw(uint8_t c);
 	virtual size_t press(uint8_t k);
+	virtual size_t pressRaw(uint8_t k);
 	virtual size_t release(uint8_t k);
+	virtual size_t releaseRaw(uint8_t k);
 	virtual void releaseAll(void);
 	virtual size_t systemControl(uint8_t k);
 };
diff --git a/hardware/keyboardio/cores/keyboardio/USBCore.cpp b/hardware/keyboardio/cores/keyboardio/USBCore.cpp
index 558a57ab..fc867f31 100644
--- a/hardware/keyboardio/cores/keyboardio/USBCore.cpp
+++ b/hardware/keyboardio/cores/keyboardio/USBCore.cpp
@@ -24,13 +24,13 @@
 
 #if defined(USBCON)
 
-#define EP_TYPE_CONTROL				0x00
-#define EP_TYPE_BULK_IN				0x81
-#define EP_TYPE_BULK_OUT			0x80
-#define EP_TYPE_INTERRUPT_IN		0xC1
-#define EP_TYPE_INTERRUPT_OUT		0xC0
-#define EP_TYPE_ISOCHRONOUS_IN		0x41
-#define EP_TYPE_ISOCHRONOUS_OUT		0x40
+#define EP_TYPE_CONTROL				(0x00)
+#define EP_TYPE_BULK_IN				((1<<EPTYPE1) | (1<<EPDIR))
+#define EP_TYPE_BULK_OUT			(1<<EPTYPE1)
+#define EP_TYPE_INTERRUPT_IN		((1<<EPTYPE1) | (1<<EPTYPE0) | (1<<EPDIR))
+#define EP_TYPE_INTERRUPT_OUT		((1<<EPTYPE1) | (1<<EPTYPE0))
+#define EP_TYPE_ISOCHRONOUS_IN		((1<<EPTYPE0) | (1<<EPDIR))
+#define EP_TYPE_ISOCHRONOUS_OUT		(1<<EPTYPE0)
 
 /** Pulse generation counters to keep track of the number of milliseconds remaining for each pulse type */
 #define TX_RX_LED_PULSE_MS 100
@@ -344,7 +344,7 @@ static
 void InitEP(u8 index, u8 type, u8 size)
 {
 	UENUM = index;
-	UECONX = 1;
+	UECONX = (1<<EPEN);
 	UECFG0X = type;
 	UECFG1X = size;
 }
@@ -355,7 +355,7 @@ void InitEndpoints()
 	for (u8 i = 1; i < sizeof(_initEndpoints); i++)
 	{
 		UENUM = i;
-		UECONX = 1;
+		UECONX = (1<<EPEN);
 		UECFG0X = pgm_read_byte(_initEndpoints+i);
 		UECFG1X = EP_DOUBLE_64;
 	}
@@ -627,11 +627,33 @@ static inline void USB_ClockEnable()
 {
 	UHWCON |= (1<<UVREGE);			// power internal reg
 	USBCON = (1<<USBE) | (1<<FRZCLK);	// clock frozen, usb enabled
+
+// ATmega32U4
+#if defined(PINDIV)
+#if F_CPU == 16000000UL
+	PLLCSR |= (1<<PINDIV);                   // Need 16 MHz xtal
+#elif F_CPU == 8000000UL
+	PLLCSR &= ~(1<<PINDIV);                  // Need  8 MHz xtal
+#endif
+
+// AT90USB646, AT90USB647, AT90USB1286, AT90USB1287 
+#elif defined(PLLP2)
 #if F_CPU == 16000000UL
-	PLLCSR = (1<<PINDIV);                   // Need 16 MHz xtal
+#if defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
+	// For Atmel AT90USB128x only. Do not use with Atmel AT90USB64x.
+	PLLCSR = (PLLCSR & ~(1<<PLLP1)) | ((1<<PLLP2) | (1<<PLLP0)); // Need 16 MHz xtal
+#elif defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__)
+	// For AT90USB64x only. Do not use with AT90USB128x.
+	PLLCSR = (PLLCSR & ~(1<<PLLP0)) | ((1<<PLLP2) | (1<<PLLP1)); // Need 16 MHz xtal
+#else
+#error "USB Chip not supported, please defined method of PLL initialization yourself"
+#endif
 #elif F_CPU == 8000000UL
-	PLLCSR = 0x00;				// Need 8 MHz xtal
+	// for Atmel AT90USB128x and AT90USB64x
+	PLLCSR = (PLLCSR & ~(1<<PLLP2)) | ((1<<PLLP1) | (1<<PLLP0)); // Need 8 MHz xtal
+#endif
 #endif
+
 	PLLCSR |= (1<<PLLE);
 	while (!(PLLCSR & (1<<PLOCK)))		// wait for lock pll
 	{
@@ -642,7 +664,13 @@ static inline void USB_ClockEnable()
 	// port touch at 1200 bps. This delay fixes this behaviour.
 	delay(1);
 	USBCON = (USBCON & ~(1<<FRZCLK)) | (1<<OTGPADE);	// start USB clock, enable VBUS Pad
+
+#if defined(RSTCPU)
 	UDCON &= ~((1<<RSTCPU) | (1<<LSM) | (1<<RMWKUP) | (1<<DETACH));	// enable attach resistor, set full speed mode
+#else
+	// AT90USB64x and AT90USB128x don't have RSTCPU
+	UDCON &= ~((1<<LSM) | (1<<RMWKUP) | (1<<DETACH));	// enable attach resistor, set full speed mode
+#endif
 }