if (usbstack.setup.bmRequest & 0x80)		// host-to-device : IN token
		{
			usbstack.pid  = PID_IN;	
			
			if(!usbXfer())
				return FALSE;
			usbstack.pid  = PID_OUT;
		}
		else											// device-to-host : OUT token
   		{							
			usbstack.pid  = PID_OUT;
				
			if(!usbXfer())
				return FALSE;
			usbstack.pid  = PID_IN;
		}
	}
	DelayMs(200);
	//----------------------------------------------------
	// Status stage IN or OUT zero-length data packet
	//----------------------------------------------------
	usbstack.wLen=0;
	if(!usbXfer())
		return FALSE;

	return TRUE;											
					
}


unsigned char epBulkSend(unsigned char *pBuffer,unsigned int len)
{
	usbstack.usbaddr=0x1;
	usbstack.endpoint=usbstack.epbulkout;
	usbstack.pid=PID_OUT;
	usbstack.wPayload=64;
	usbstack.wLen=len;
	usbstack.buffer=pBuffer;
	while(len>0)
	{
		if (len > usbstack.wPayload)
			usbstack.wLen = usbstack.wPayload;
		else				
			usbstack.wLen = len;	
		if(!usbXfer())
			return FALSE;
		len-=usbstack.wLen;
		usbstack.buffer=usbstack.buffer+usbstack.wLen;
	}
	return TRUE;	
}

unsigned char epBulkRcv(unsigned char *pBuffer,unsigned int len)
{
	usbstack.usbaddr=0x1;
	usbstack.endpoint=usbstack.epbulkin;
	usbstack.pid=PID_IN;
	usbstack.wPayload=64;
	usbstack.wLen=len;
	usbstack.buffer=pBuffer;
	if(usbstack.wLen)
	{
		if(!usbXfer())
			return FALSE;
	}
	return TRUE;
}

//*****************************************************************************************
// Set Device Address : 
//*****************************************************************************************
unsigned char SetAddress(unsigned char addr)
{
	usbstack.usbaddr=0;
	usbstack.setup.bmRequest=0;
	usbstack.setup.bRequest=SET_ADDRESS;
	usbstack.setup.wValue=addr;
	usbstack.setup.wIndex=0;
	usbstack.setup.wLength=0;
	return ep0Xfer();

}

//*****************************************************************************************
// Set Device Configuration : 
//*****************************************************************************************
unsigned char Set_Configuration(void)
{
	usbstack.setup.bmRequest=0;
	usbstack.setup.bRequest=SET_CONFIG;
	
	usbstack.setup.wIndex=0;
	usbstack.setup.wLength=0;
	usbstack.buffer=NULL;
	return ep0Xfer();

}

//*****************************************************************************************
// Get Device Descriptor : Device, Configuration, String
//*****************************************************************************************
unsigned char GetDesc(void)
{ 
	
	usbstack.setup.bmRequest=0x80;
	usbstack.setup.bRequest=GET_DESCRIPTOR;
	usbstack.setup.wValue=WordSwap(usbstack.setup.wValue);	
	usbstack.wPayload=uDev.wPayLoad[0];
	
	return ep0Xfer();
}

//*****************************************************************************************
// USB Device Enumeration Process
// Support 1 confguration and interface #0 and alternate setting #0 only
// Support up to 1 control endpoint + 4 data endpoint only
//*****************************************************************************************
unsigned char EnumUsbDev(BYTE usbaddr)
{  
	unsigned char i;					// always reset USB transfer address 
	unsigned char uAddr = 0;			// for enumeration to Address #0
	unsigned char epLen;
		
	//------------------------------------------------
	// Reset only Slave device attached directly
	//------------------------------------------------
	uDev.wPayLoad[0] = 64;	// default 64-byte payload of Endpoint 0, address #0
	if(usbaddr == 1)		// bus reset for the device attached to SL811HS only
		USBReset();		    // that will always have the USB address = 0x01 (for a hub)
    	
    	DelayMs(25);
	
	//------------------------------------------------
	// Get USB Device Descriptors on EP0 & Addr 0
	// with default 64-byte payload
	//------------------------------------------------
		
	usbstack.usbaddr=uAddr;
	usbstack.setup.wValue=DEVICE;
	usbstack.setup.wIndex=0;
	usbstack.setup.wLength=18;
	usbstack.buffer=DBUF;
	
	if (!GetDesc())			// and determine the wPayload size
		return FALSE;								// get correct wPayload of Endpoint 0
	uDev.wPayLoad[0]=DBUF[7];	// on current non-zero USB address
	//------------------------------------------------
	// Set Slave USB Device Address
	//------------------------------------------------
	if (!SetAddress(usbaddr)) 						// set to specific USB address
		return FALSE;								//
	uAddr = usbaddr;								// transfer using this new address

	//------------------------------------------------
	// Get USB Device Descriptors on EP0 & Addr X
	//------------------------------------------------
	

	usbstack.usbaddr=uAddr;	
	usbstack.setup.wLength=DBUF[0];	
	usbstack.setup.wValue=DEVICE;
	usbstack.setup.wIndex=0;	
	usbstack.buffer=DBUF;	
	if (!GetDesc()) 	
		return FALSE;								// For this current device:
	uDev.iMfg  = DBUF[14];	
	uDev.iPdt  = DBUF[15];

	//------------------------------------------------
	// Get Slave USB Configuration Descriptors
	//------------------------------------------------
	
	usbstack.usbaddr=uAddr;
	usbstack.setup.wValue=CONFIGURATION;
	usbstack.setup.wIndex=0;
	usbstack.setup.wLength=64;
	usbstack.buffer=DBUF;	
	if (!GetDesc()) 		
		return FALSE;	

	uDev.bClass 	= DBUF[9+5] & 0xFF;	// update to class type
	uDev.bNumOfEPs = (DBUF[9+4] <= MAX_EP) ? DBUF[9+4] : MAX_EP;
	if(uDev.bClass==8) //mass storage device
		bFlags.bits.bMassDevice=TRUE;
	//------------------------------------------------
	// Set configuration (except for HUB device)
	//------------------------------------------------
	usbstack.usbaddr=uAddr;
	usbstack.setup.wValue=DEVICE;
					// enumerating a FS/LS non-hub device
		if (!Set_Configuration())		// connected directly to SL811HS
				return FALSE;

	//------------------------------------------------
	// For each slave endpoints, get its attributes
	// Excluding endpoint0, only data endpoints
	//------------------------------------------------
	
	epLen = 0;
	for (i=1; i<=uDev.bNumOfEPs; i++)				// For each data endpoint
	{
		uDev.bEPAddr[i]		= DBUF[9 + 9 + epLen+2] & 0xFF;	// Ep address and direction				
		uDev.bAttr[i]		= DBUF[9 + 9 + epLen+3] & 0xFF;	// Attribute of Endpoint			
		uDev.wPayLoad[i] 	= LSwapINT16(DBUF[9 + 9 + epLen+4],DBUF[9 + 9 + epLen+5]);	// Payload of Endpoint
		uDev.bInterval[i] 	= DBUF[9 + 9 + epLen+6];	// Polling interval
	    uDev.bData1[i] = 0;			            // init data toggle
		epLen += 7;
		//////////////////////////////
		if(uDev.bAttr[i]==0x2)     //bulk transfer
		{
		    if(uDev.bEPAddr[i]&0x80)
		    	usbstack.epbulkin=uDev.bEPAddr[i];
		    else
		    	usbstack.epbulkout=uDev.bEPAddr[i];
		}
		//////////////////////////////
	}
	
	return TRUE;
}

///////////////////////////////////////////////////////////////////////////////////////////
void SL811_Init(void)
{	
	bFlags.bits.SLAVE_ONLINE = FALSE;
	bFlags.bits.SLAVE_FOUND = FALSE;
	bFlags.bits.SLAVE_REMOVED=FALSE;
	
	bFlags.bits.SLAVE_ENUMERATED = FALSE;
	bFlags.bits.SLAVE_IS_ATTACHED = FALSE;
	///////////////////////////////////////////////////////
	SL811Write(CtrlReg,0x00);  //0x04
	DelayMs(100);
	SL811Write(CtrlReg,0x01);
	
	SL811Write(cDATASet,0xe0);
	SL811Write(cSOFcnt,0xae);
			
	SL811Write(EP0Status,0x50);
	SL811Write(EP0Counter,0);
	SL811Write(EP0Control,0x01);
		
	SL811Write(IntEna,0x20);      		// USB-A, Insert/Remove, USB_Resume.
	
	SL811Write(IntStatus,INT_CLEAR);	// Clear Interrupt enable status
}

void check_usb(void)
{
	unsigned char  intr;
	
	intr=SL811Read(IntStatus);
	if (intr & 0x40)
		{
		   		
		 	if(bFlags.bits.SLAVE_ONLINE ==TRUE)
		 		{
		 			bFlags.bits.SLAVE_REMOVED=TRUE;
		 			bFlags.bits.SLAVE_ONLINE =FALSE;
		 		}
	   	}
	else{
		   		
		  	if(bFlags.bits.SLAVE_ONLINE == FALSE)
		   		{
		   			bFlags.bits.SLAVE_FOUND=TRUE;
		   			bFlags.bits.SLAVE_ONLINE =TRUE;
		   		}
		}	
	SL811Write(IntStatus,INT_CLEAR);
	SL811Write(IntStatus,INSERT_REMOVE);
		
}