text: 
  
  /* Copyright (c) 2010, Peter Barrett
  ** Sleep/Wakeup support added by Michael Dreher
  **  
  ** 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.  
  ** 
  ** THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL  
  ** WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED  
  ** WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR  
  ** BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES  
  ** OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,  
  ** WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,  
  ** ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS  
  ** SOFTWARE.  
  */
  
  #include "USBAPI.h"
  #include "PluggableUSB.h"
  #include <stdlib.h>
  #include <string.h>
  
  #if defined(USBCON)
  
  /** Pulse generation counters to keep track of the number of milliseconds remaining for each pulse type */
  #define TX_RX_LED_PULSE_MS 100
  volatile u8 TxLEDPulse; /**< Milliseconds remaining for data Tx LED pulse */
  volatile u8 RxLEDPulse; /**< Milliseconds remaining for data Rx LED pulse */
  
  //==================================================================
  //==================================================================
  
  extern const u16 STRING_LANGUAGE[] PROGMEM;
  extern const u8 STRING_PRODUCT[] PROGMEM;
  extern const u8 STRING_MANUFACTURER[] PROGMEM;
  extern const DeviceDescriptor USB_DeviceDescriptorIAD PROGMEM;
  extern bool _updatedLUFAbootloader;
  
  const u16 STRING_LANGUAGE[2] = {
  	(3<<8) | (2+2),
  	0x0409	// English
  };
  
  #ifndef USB_PRODUCT
  // If no product is provided, use USB IO Board
  #define USB_PRODUCT     "USB IO Board"
  #endif
  
  const u8 STRING_PRODUCT[] PROGMEM = USB_PRODUCT;
  
  #if USB_VID == 0x2341
  #  if defined(USB_MANUFACTURER)
  #    undef USB_MANUFACTURER
  #  endif
  #  define USB_MANUFACTURER "Arduino LLC"
  #elif USB_VID == 0x1b4f
  #  if defined(USB_MANUFACTURER)
  #    undef USB_MANUFACTURER
  #  endif
  #  define USB_MANUFACTURER "SparkFun"
  #elif !defined(USB_MANUFACTURER)
  // Fall through to unknown if no manufacturer name was provided in a macro
  #  define USB_MANUFACTURER "Unknown"
  #endif
  
  const u8 STRING_MANUFACTURER[] PROGMEM = USB_MANUFACTURER;
  
  #define DEVICE_CLASS 0x02
  
  //	DEVICE DESCRIPTOR
  const DeviceDescriptor USB_DeviceDescriptorIAD =
  	D_DEVICE(0xEF,0x02,0x01,64,USB_VID,USB_PID,0x100,IMANUFACTURER,IPRODUCT,ISERIAL,1);
  
  //==================================================================
  //==================================================================
  
  volatile u8 _usbConfiguration = 0;
  volatile u8 _usbCurrentStatus = 0; // meaning of bits see usb_20.pdf, Figure 9-4. Information Returned by a GetStatus() Request to a Device
  volatile u8 _usbSuspendState = 0; // copy of UDINT to check SUSPI and WAKEUPI bits
  
  static inline void WaitIN(void)
  {
  	while (!(UEINTX & (1<<TXINI)))
  		;
  }
  
  static inline void ClearIN(void)
  {
  	UEINTX = ~(1<<TXINI);
  }
  
  static inline void WaitOUT(void)
  {
  	while (!(UEINTX & (1<<RXOUTI)))
  		;
  }
  
  static inline u8 WaitForINOrOUT()
  {
  	while (!(UEINTX & ((1<<TXINI)|(1<<RXOUTI))))
  		;
  	return (UEINTX & (1<<RXOUTI)) == 0;
  }
  
  static inline void ClearOUT(void)
  {
  	UEINTX = ~(1<<RXOUTI);
  }
  
  static inline void Recv(volatile u8* data, u8 count)
  {
  	while (count--)
  		*data++ = UEDATX;
  	
  	RXLED1;					// light the RX LED
  	RxLEDPulse = TX_RX_LED_PULSE_MS;	
  }
  
  static inline u8 Recv8()
  {
  	RXLED1;					// light the RX LED
  	RxLEDPulse = TX_RX_LED_PULSE_MS;
  
  	return UEDATX;	
  }
  
  static inline void Send8(u8 d)
  {
  	UEDATX = d;
  }
  
  static inline void SetEP(u8 ep)
  {
  	UENUM = ep;
  }
  
  static inline u8 FifoByteCount()
  {
  	return UEBCLX;
  }
  
  static inline u8 ReceivedSetupInt()
  {
  	return UEINTX & (1<<RXSTPI);
  }
  
  static inline void ClearSetupInt()
  {
  	UEINTX = ~((1<<RXSTPI) | (1<<RXOUTI) | (1<<TXINI));
  }
  
  static inline void Stall()
  {
  	UECONX = (1<<STALLRQ) | (1<<EPEN);
  }
  
  static inline u8 ReadWriteAllowed()
  {
  	return UEINTX & (1<<RWAL);
  }
  
  static inline u8 Stalled()
  {
  	return UEINTX & (1<<STALLEDI);
  }
  
  static inline u8 FifoFree()
  {
  	return UEINTX & (1<<FIFOCON);
  }
  
  static inline void ReleaseRX()
  {
  	UEINTX = 0x6B;	// FIFOCON=0 NAKINI=1 RWAL=1 NAKOUTI=0 RXSTPI=1 RXOUTI=0 STALLEDI=1 TXINI=1
  }
  
  static inline void ReleaseTX()
  {
  	UEINTX = 0x3A;	// FIFOCON=0 NAKINI=0 RWAL=1 NAKOUTI=1 RXSTPI=1 RXOUTI=0 STALLEDI=1 TXINI=0
  }
  
  static inline u8 FrameNumber()
  {
  	return UDFNUML;
  }
  
  //==================================================================
  //==================================================================
  
  u8 USBGetConfiguration(void)
  {
  	return _usbConfiguration;
  }
  
  #define USB_RECV_TIMEOUT
  class LockEP
  {
  	u8 _sreg;
  public:
  	LockEP(u8 ep) : _sreg(SREG)
  	{
  		cli();
  		SetEP(ep & 7);
  	}
  	~LockEP()
  	{
  		SREG = _sreg;
  	}
  };
  
  //	Number of bytes, assumes a rx endpoint
  u8 USB_Available(u8 ep)
  {
  	LockEP lock(ep);
  	return FifoByteCount();
  }
  
  //	Non Blocking receive
  //	Return number of bytes read
  int USB_Recv(u8 ep, void* d, int len)
  {
  	if (!_usbConfiguration || len < 0)
  		return -1;
  	
  	LockEP lock(ep);
  	u8 n = FifoByteCount();
  	len = min(n,len);
  	n = len;
  	u8* dst = (u8*)d;
  	while (n--)
  		*dst++ = Recv8();
  	if (len && !FifoByteCount())	// release empty buffer
  		ReleaseRX();
  	
  	return len;
  }
  
  //	Recv 1 byte if ready
  int USB_Recv(u8 ep)
  {
  	u8 c;
  	if (USB_Recv(ep,&c,1) != 1)
  		return -1;
  	return c;
  }
  
  //	Space in send EP
  u8 USB_SendSpace(u8 ep)
  {
  	LockEP lock(ep);
  	if (!ReadWriteAllowed())
  		return 0;
  	return USB_EP_SIZE - FifoByteCount();
  }
  
  //	Blocking Send of data to an endpoint
  int USB_Send(u8 ep, const void* d, int len)
  {
  	if (!_usbConfiguration)
  		return -1;
  
  	if (_usbSuspendState & (1<<SUSPI)) {
  		//send a remote wakeup
  		UDCON |= (1 << RMWKUP);
  	}
  
  	int r = len;
  	const u8* data = (const u8*)d;
  	u8 timeout = 250;		// 250ms timeout on send? TODO
  	bool sendZlp = false;
  
  	while (len || sendZlp)
  	{
  		u8 n = USB_SendSpace(ep);
  		if (n == 0)
  		{
  			if (!(--timeout))
  				return -1;
  			delay(1);
  			continue;
  		}
  
  		if (n > len) {
  			n = len;
  		}
  
  		{
  			LockEP lock(ep);
  			// Frame may have been released by the SOF interrupt handler
  			if (!ReadWriteAllowed())
  				continue;
  
  			len -= n;
  			if (ep & TRANSFER_ZERO)
  			{
  				while (n--)
  					Send8(0);
  			}
  			else if (ep & TRANSFER_PGM)
  			{
  				while (n--)
  					Send8(pgm_read_byte(data++));
  			}
  			else
  			{
  				while (n--)
  					Send8(*data++);
  			}
  
  			if (sendZlp) {
  				ReleaseTX();
  				sendZlp = false;
  			} else if (!ReadWriteAllowed()) { // ...release if buffer is full...
  				ReleaseTX();
  				if (len == 0) sendZlp = true;
  			} else if ((len == 0) && (ep & TRANSFER_RELEASE)) { // ...or if forced with TRANSFER_RELEASE
  				// XXX: TRANSFER_RELEASE is never used can be removed?
  				ReleaseTX();
  			}
  		}
  	}
  	TXLED1;					// light the TX LED
  	TxLEDPulse = TX_RX_LED_PULSE_MS;
  	return r;
  }
  
  u8 _initEndpoints[USB_ENDPOINTS] =
  {
  	0,                      // Control Endpoint
  	
  	EP_TYPE_INTERRUPT_IN,   // CDC_ENDPOINT_ACM
  	EP_TYPE_BULK_OUT,       // CDC_ENDPOINT_OUT
  	EP_TYPE_BULK_IN,        // CDC_ENDPOINT_IN
  
  	// Following endpoints are automatically initialized to 0
  };
  
  #define EP_SINGLE_64 0x32	// EP0
  #define EP_DOUBLE_64 0x36	// Other endpoints
  #define EP_SINGLE_16 0x12
  
  static
  void InitEP(u8 index, u8 type, u8 size)
  {
  	UENUM = index;
  	UECONX = (1<<EPEN);
  	UECFG0X = type;
  	UECFG1X = size;
  }
  
  static
  void InitEndpoints()
  {
  	for (u8 i = 1; i < sizeof(_initEndpoints) && _initEndpoints[i] != 0; i++)
  	{
  		UENUM = i;
  		UECONX = (1<<EPEN);
  		UECFG0X = _initEndpoints[i];
  #if USB_EP_SIZE == 16
  		UECFG1X = EP_SINGLE_16;
  #elif USB_EP_SIZE == 64
  		UECFG1X = EP_DOUBLE_64;
  #else
  #error Unsupported value for USB_EP_SIZE
  #endif
  	}
  	UERST = 0x7E;	// And reset them
  	UERST = 0;
  }
  
  //	Handle CLASS_INTERFACE requests
  static
  bool ClassInterfaceRequest(USBSetup& setup)
  {
  	u8 i = setup.wIndex;
  
  	if (CDC_ACM_INTERFACE == i)
  		return CDC_Setup(setup);
  
  #ifdef PLUGGABLE_USB_ENABLED
  	return PluggableUSB().setup(setup);
  #endif
  	return false;
  }
  
  static int _cmark;
  static int _cend;
  void InitControl(int end)
  {
  	SetEP(0);
  	_cmark = 0;
  	_cend = end;
  }
  
  static
  bool SendControl(u8 d)
  {
  	if (_cmark < _cend)
  	{
  		if (!WaitForINOrOUT())
  			return false;
  		Send8(d);
  		if (!((_cmark + 1) & 0x3F))
  			ClearIN();	// Fifo is full, release this packet
  	}
  	_cmark++;
  	return true;
  }
  
  //	Clipped by _cmark/_cend
  int USB_SendControl(u8 flags, const void* d, int len)
  {
  	int sent = len;
  	const u8* data = (const u8*)d;
  	bool pgm = flags & TRANSFER_PGM;
  	while (len--)
  	{
  		u8 c = pgm ? pgm_read_byte(data++) : *data++;
  		if (!SendControl(c))
  			return -1;
  	}
  	return sent;
  }
  
  // Send a USB descriptor string. The string is stored in PROGMEM as a
  // plain ASCII string but is sent out as UTF-16 with the correct 2-byte
  // prefix
  static bool USB_SendStringDescriptor(const u8*string_P, u8 string_len, uint8_t flags) {
          SendControl(2 + string_len * 2);
          SendControl(3);
          bool pgm = flags & TRANSFER_PGM;
          for(u8 i = 0; i < string_len; i++) {
                  bool r = SendControl(pgm ? pgm_read_byte(&string_P[i]) : string_P[i]);
                  r &= SendControl(0); // high byte
                  if(!r) {
                          return false;
                  }
          }
          return true;
  }
  
  //	Does not timeout or cross fifo boundaries
  int USB_RecvControl(void* d, int len)
  {
  	auto length = len;
  	while(length)
  	{
  		// Dont receive more than the USB Control EP has to offer
  		// Use fixed 64 because control EP always have 64 bytes even on 16u2.
  		auto recvLength = length;
  		if(recvLength > 64){
  			recvLength = 64;
  		}
  
  		// Write data to fit to the end (not the beginning) of the array
  		WaitOUT();
  		Recv((u8*)d + len - length, recvLength);
  		ClearOUT();
  		length -= recvLength;
  	}
  	return len;
  }
  
  static u8 SendInterfaces()
  {
  	u8 interfaces = 0;
  
  	CDC_GetInterface(&interfaces);
  
  #ifdef PLUGGABLE_USB_ENABLED
  	PluggableUSB().getInterface(&interfaces);
  #endif
  
  	return interfaces;
  }
  
  //	Construct a dynamic configuration descriptor
  //	This really needs dynamic endpoint allocation etc
  //	TODO
  static
  bool SendConfiguration(int maxlen)
  {
  	//	Count and measure interfaces
  	InitControl(0);
  	u8 interfaces = SendInterfaces();
  	ConfigDescriptor config = D_CONFIG(_cmark + sizeof(ConfigDescriptor),interfaces);
  
  	//	Now send them
  	InitControl(maxlen);
  	USB_SendControl(0,&config,sizeof(ConfigDescriptor));
  	SendInterfaces();
  	return true;
  }
  
  static
  bool SendDescriptor(USBSetup& setup)
  {
  	int ret;
  	u8 t = setup.wValueH;
  	if (USB_CONFIGURATION_DESCRIPTOR_TYPE == t)
  		return SendConfiguration(setup.wLength);
  
  	InitControl(setup.wLength);
  #ifdef PLUGGABLE_USB_ENABLED
  	ret = PluggableUSB().getDescriptor(setup);
  	if (ret != 0) {
  		return (ret > 0 ? true : false);
  	}
  #endif
  
  	const u8* desc_addr = 0;
  	if (USB_DEVICE_DESCRIPTOR_TYPE == t)
  	{
          uint8_t freeit = USB_GetCustomDescriptor(&desc_addr);
          if (desc_addr)
          {
              ret = USB_SendControl(0, desc_addr, *desc_addr);
              if (freeit) free((void *)desc_addr);
              return ret;
          }
          else
          {
  		    desc_addr = (const u8*)&USB_DeviceDescriptorIAD;
          }
  	}
  	else if (USB_STRING_DESCRIPTOR_TYPE == t)
  	{
  		if (setup.wValueL == 0) {
  			desc_addr = (const u8*)&STRING_LANGUAGE;
  		}
  		else if (setup.wValueL == IPRODUCT) {
  			return USB_SendStringDescriptor(STRING_PRODUCT, strlen(USB_PRODUCT), TRANSFER_PGM);
  		}
  		else if (setup.wValueL == IMANUFACTURER) {
  			return USB_SendStringDescriptor(STRING_MANUFACTURER, strlen(USB_MANUFACTURER), TRANSFER_PGM);
  		}
  		else if (setup.wValueL == ISERIAL) 
          {			
  			uint8_t freeit = USB_GetCustomSerialNumber( &desc_addr );
  			if (desc_addr)
  			{
  				ret = USB_SendControl(0, desc_addr, *desc_addr);
                  if (freeit) free((void *)desc_addr);
                  return ret;
  			}
  	    #ifdef PLUGGABLE_USB_ENABLED
  			else
  			{
  				char name[ISERIAL_MAX_LEN];
  				PluggableUSB().getShortName(name);
  				return USB_SendStringDescriptor((uint8_t*)name, strlen(name), 0);
  			}
  	    #endif
  		}
  		else
  			return false;
  	}
  
  	if (desc_addr == 0)
  		return false;
  	u8 desc_length = pgm_read_byte(desc_addr);
  
  	USB_SendControl(TRANSFER_PGM,desc_addr,desc_length);
  	return true;
  }
  
  //	Endpoint 0 interrupt
  ISR(USB_COM_vect)
  {
      SetEP(0);
  	if (!ReceivedSetupInt())
  		return;
  
  	USBSetup setup;
  	Recv((u8*)&setup,8);
  	ClearSetupInt();
  
  	u8 requestType = setup.bmRequestType;
  	if (requestType & REQUEST_DEVICETOHOST)
  		WaitIN();
  	else
  		ClearIN();
  
      bool ok = true;
  	if (REQUEST_STANDARD == (requestType & REQUEST_TYPE))
  	{
  		//	Standard Requests
  		u8 r = setup.bRequest;
  		u16 wValue = setup.wValueL | (setup.wValueH << 8);
  		if (GET_STATUS == r)
  		{
  			if (requestType == (REQUEST_DEVICETOHOST | REQUEST_STANDARD | REQUEST_DEVICE))
  			{
  				Send8(_usbCurrentStatus);
  				Send8(0);
  			}
  			else
  			{
  				// TODO: handle the HALT state of an endpoint here
  				// see "Figure 9-6. Information Returned by a GetStatus() Request to an Endpoint" in usb_20.pdf for more information
  				Send8(0);
  				Send8(0);
  			}
  		}
  		else if (CLEAR_FEATURE == r)
  		{
  			if((requestType == (REQUEST_HOSTTODEVICE | REQUEST_STANDARD | REQUEST_DEVICE))
  				&& (wValue == DEVICE_REMOTE_WAKEUP))
  			{
  				_usbCurrentStatus &= ~FEATURE_REMOTE_WAKEUP_ENABLED;
  			}
  		}
  		else if (SET_FEATURE == r)
  		{
  			if((requestType == (REQUEST_HOSTTODEVICE | REQUEST_STANDARD | REQUEST_DEVICE))
  				&& (wValue == DEVICE_REMOTE_WAKEUP))
  			{
  				_usbCurrentStatus |= FEATURE_REMOTE_WAKEUP_ENABLED;
  			}
  		}
  		else if (SET_ADDRESS == r)
  		{
  			WaitIN();
  			UDADDR = setup.wValueL | (1<<ADDEN);
  		}
  		else if (GET_DESCRIPTOR == r)
  		{
  			ok = SendDescriptor(setup);
  		}
  		else if (SET_DESCRIPTOR == r)
  		{
  			ok = false;
  		}
  		else if (GET_CONFIGURATION == r)
  		{
  			Send8(1);
  		}
  		else if (SET_CONFIGURATION == r)
  		{
  			if (REQUEST_DEVICE == (requestType & REQUEST_RECIPIENT))
  			{
  				InitEndpoints();
  				_usbConfiguration = setup.wValueL;
  			} else
  				ok = false;
  		}
  		else if (GET_INTERFACE == r)
  		{
  		}
  		else if (SET_INTERFACE == r)
  		{
  		}
  	}
  	else
  	{
  		InitControl(setup.wLength);		//	Max length of transfer
  		ok = ClassInterfaceRequest(setup);
  	}
  
  	if (ok)
  		ClearIN();
  	else
  	{
  		Stall();
  	}
  }
  
  void USB_Flush(u8 ep)
  {
  	SetEP(ep);
  	if (FifoByteCount())
  		ReleaseTX();
  }
  
  static inline void USB_ClockDisable()
  {
  #if defined(OTGPADE)
  	USBCON = (USBCON & ~(1<<OTGPADE)) | (1<<FRZCLK); // freeze clock and disable VBUS Pad
  #else // u2 Series
  	USBCON = (1 << FRZCLK); // freeze clock
  #endif
  	PLLCSR &= ~(1<<PLLE);  // stop PLL
  }
  
  static inline void USB_ClockEnable()
  {
  #if defined(UHWCON)
  	UHWCON |= (1<<UVREGE);			// power internal reg
  #endif
  	USBCON = (1<<USBE) | (1<<FRZCLK);	// clock frozen, usb enabled
  
  // ATmega32U4
  #if defined(PINDIV)
  	
  //
  // CHANGE: The original logic did not support running an ATmega32u4
  //         on 3.3V with a 16MHz input clock with prescaling so the 
  //		   F_CPU is 8MHz. The decision to set USB PLL prescale bit 
  //		   depends on the input hardware clock freq, NOT F_CPU.
  //		   We define a new macro, F_USB which can be set for compilation
  //		   in the boards.txt file.
  //
  #ifdef F_USB
  #define F_XTAL F_USB
  #else
  #define F_XTAL F_CPU
  #endif
  
  #if F_XTAL == 16000000UL
  	PLLCSR |= (1<<PINDIV);				// prescale 1:2
  #elif F_XTAL == 8000000UL
  	PLLCSR &= ~(1<<PINDIV);				// prescale 1:1
  #else
  #error "Clock rate of F_USB (or F_CPU if F_USB is not specified) not supported"
  #endif
  
  #elif defined(__AVR_AT90USB82__) || defined(__AVR_AT90USB162__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega8U2__)
  	// for the u2 Series the datasheet is confusing. On page 40 its called PINDIV and on page 290 its called PLLP0
  #if F_CPU == 16000000UL
  	// Need 16 MHz xtal
  	PLLCSR |= (1 << PLLP0);
  #elif F_CPU == 8000000UL
  	// Need 8 MHz xtal
  	PLLCSR &= ~(1 << PLLP0);
  #endif
  
  // AT90USB646, AT90USB647, AT90USB1286, AT90USB1287
  #elif defined(PLLP2)
  #if F_CPU == 16000000UL
  #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 USB PLL initialization"
  #endif
  #elif F_CPU == 8000000UL
  	// for Atmel AT90USB128x and AT90USB64x
  	PLLCSR = (PLLCSR & ~(1<<PLLP2)) | ((1<<PLLP1) | (1<<PLLP0)); // Need 8 MHz xtal
  #else
  #error "Clock rate of F_CPU not supported"
  #endif
  #else
  #error "USB Chip not supported, please defined method of USB PLL initialization"
  #endif
  
  	PLLCSR |= (1<<PLLE);
  	while (!(PLLCSR & (1<<PLOCK)))		// wait for lock pll
  	{
  	}
  
  	// Some tests on specific versions of macosx (10.7.3), reported some
  	// strange behaviors when the board is reset using the serial
  	// port touch at 1200 bps. This delay fixes this behavior.
  	delay(1);
  #if defined(OTGPADE)
  	USBCON = (USBCON & ~(1<<FRZCLK)) | (1<<OTGPADE);	// start USB clock, enable VBUS Pad
  #else
  	USBCON &= ~(1 << FRZCLK);	// start USB clock
  #endif
  
  #if defined(RSTCPU)
  #if defined(LSM)
  	UDCON &= ~((1<<RSTCPU) | (1<<LSM) | (1<<RMWKUP) | (1<<DETACH));	// enable attach resistor, set full speed mode
  #else // u2 Series
  	UDCON &= ~((1 << RSTCPU) | (1 << RMWKUP) | (1 << DETACH));	// enable attach resistor, set full speed mode
  #endif
  #else
  	// AT90USB64x and AT90USB128x don't have RSTCPU
  	UDCON &= ~((1<<LSM) | (1<<RMWKUP) | (1<<DETACH));	// enable attach resistor, set full speed mode
  #endif
  }
  //
  // This weak function gives the sketch an ability to override it
  // and provide a custom serial number for enumeration on USB.
  //
  uint8_t __attribute__ ((weak)) USB_GetCustomSerialNumber(const uint8_t **buffer)
  {
      if (!buffer) return 0;
      *buffer = 0;
      return 0;
  }
  
  uint8_t __attribute__ ((weak)) USB_GetCustomDescriptor(const uint8_t **buffer)
  {
      if (!buffer) return 0;
      *buffer = 0;
      return 0;
  }
  
  //	General interrupt
  ISR(USB_GEN_vect)
  {
  	u8 udint = UDINT;
  	UDINT &= ~((1<<EORSTI) | (1<<SOFI)); // clear the IRQ flags for the IRQs which are handled here, except WAKEUPI and SUSPI (see below)
  
  	//	End of Reset
  	if (udint & (1<<EORSTI))
  	{
  		InitEP(0,EP_TYPE_CONTROL,EP_SINGLE_64);	// init ep0
  		_usbConfiguration = 0;			// not configured yet
  		UEIENX = 1 << RXSTPE;			// Enable interrupts for ep0
  	}
  
  	//	Start of Frame - happens every millisecond so we use it for TX and RX LED one-shot timing, too
  	if (udint & (1<<SOFI))
  	{
  		USB_Flush(CDC_TX);				// Send a tx frame if found
  		
  		// check whether the one-shot period has elapsed.  if so, turn off the LED
  		if (TxLEDPulse && !(--TxLEDPulse))
  			TXLED0;
  		if (RxLEDPulse && !(--RxLEDPulse))
  			RXLED0;
  	}
  
  	// the WAKEUPI interrupt is triggered as soon as there are non-idle patterns on the data
  	// lines. Thus, the WAKEUPI interrupt can occur even if the controller is not in the "suspend" mode.
  	// Therefore the we enable it only when USB is suspended
  	if (udint & (1<<WAKEUPI))
  	{
  		UDIEN = (UDIEN & ~(1<<WAKEUPE)) | (1<<SUSPE); // Disable interrupts for WAKEUP and enable interrupts for SUSPEND
  
  		//TODO
  		// WAKEUPI shall be cleared by software (USB clock inputs must be enabled before).
  		//USB_ClockEnable();
  		UDINT &= ~(1<<WAKEUPI);
  		_usbSuspendState = (_usbSuspendState & ~(1<<SUSPI)) | (1<<WAKEUPI);
  	}
  	else if (udint & (1<<SUSPI)) // only one of the WAKEUPI / SUSPI bits can be active at time
  	{
  		UDIEN = (UDIEN & ~(1<<SUSPE)) | (1<<WAKEUPE); // Disable interrupts for SUSPEND and enable interrupts for WAKEUP
  
  		//TODO
  		//USB_ClockDisable();
  
  		UDINT &= ~((1<<WAKEUPI) | (1<<SUSPI)); // clear any already pending WAKEUP IRQs and the SUSPI request
  		_usbSuspendState = (_usbSuspendState & ~(1<<WAKEUPI)) | (1<<SUSPI);
  	}
  }
  
  //	VBUS or counting frames
  //	Any frame counting?
  u8 USBConnected()
  {
  	u8 f = UDFNUML;
  	delay(3);
  	return f != UDFNUML;
  }
  
  //=======================================================================
  //=======================================================================
  
  USBDevice_ USBDevice;
  
  USBDevice_::USBDevice_()
  {
  }
  
  void USBDevice_::attach()
  {
  	_usbConfiguration = 0;
  	_usbCurrentStatus = 0;
  	_usbSuspendState = 0;
  	USB_ClockEnable();
  
  	UDINT &= ~((1<<WAKEUPI) | (1<<SUSPI)); // clear already pending WAKEUP / SUSPEND requests
  	UDIEN = (1<<EORSTE) | (1<<SOFE) | (1<<SUSPE);	// Enable interrupts for EOR (End of Reset), SOF (start of frame) and SUSPEND
  	
  	TX_RX_LED_INIT;
  
  #if MAGIC_KEY_POS != (RAMEND-1)
  	if (pgm_read_word(FLASHEND - 1) == NEW_LUFA_SIGNATURE) {
  		_updatedLUFAbootloader = true;
  	}
  #endif
  }
  
  void USBDevice_::detach()
  {
  }
  
  //	Check for interrupts
  //	TODO: VBUS detection
  bool USBDevice_::configured()
  {
  	return _usbConfiguration;
  }
  
  void USBDevice_::poll()
  {
  }
  
  bool USBDevice_::wakeupHost()
  {
  	// clear any previous wakeup request which might have been set but could be processed at that time
  	// e.g. because the host was not suspended at that time
  	UDCON &= ~(1 << RMWKUP);
  
  	if(!(UDCON & (1 << RMWKUP))
  	  && (_usbSuspendState & (1<<SUSPI))
  	  && (_usbCurrentStatus & FEATURE_REMOTE_WAKEUP_ENABLED))
  	{
  		// This short version will only work, when the device has not been suspended. Currently the
  		// Arduino core doesn't handle SUSPEND at all, so this is ok.
  		USB_ClockEnable();
  		UDCON |= (1 << RMWKUP); // send the wakeup request
  		return true;
  	}
  
  	return false;
  }
  
  #endif /* if defined(USBCON) */
  