{
			ulNextRxBuffer = 0;
		}
	}

	/* Is there a packet ready? */

	while( ( xRxDescriptors[ ulNextRxBuffer ].addr & AT91C_OWNERSHIP_BIT ) && !ulSectionLength )
	{
		pcSource = ( portCHAR * )( xRxDescriptors[ ulNextRxBuffer ].addr & emacADDRESS_MASK );
		ulSectionLength = xRxDescriptors[ ulNextRxBuffer ].U_Status.status & emacRX_LENGTH_FRAME;

		if( ulSectionLength == 0 )
		{
			/* The frame is longer than the buffer pointed to by this
			descriptor so copy the entire buffer to uIP - then move onto
			the next descriptor to get the rest of the frame. */
			if( ( ulLengthSoFar + ETH_RX_BUFFER_SIZE ) <= UIP_BUFSIZE )
			{
				memcpy( &( uip_buf[ ulLengthSoFar ] ), pcSource, ETH_RX_BUFFER_SIZE );
				ulLengthSoFar += ETH_RX_BUFFER_SIZE;
			}			
		}
		else
		{
			/* This is the last section of the frame.  Copy the section to
			uIP. */
			if( ulSectionLength < UIP_BUFSIZE )
			{
				/* The section length holds the length of the entire frame.
				ulLengthSoFar holds the length of the frame sections already
				copied to uIP, so the length of the final section is
				ulSectionLength - ulLengthSoFar; */
				if( ulSectionLength > ulLengthSoFar )
				{
					memcpy( &( uip_buf[ ulLengthSoFar ] ), pcSource, ( ulSectionLength - ulLengthSoFar ) );
				}
			}			

			/* Is this the last buffer for the frame?  If not why? */
			ulEOF = xRxDescriptors[ ulNextRxBuffer ].U_Status.status & AT91C_EOF;
		}

		/* Mark the buffer as free again. */
		xRxDescriptors[ ulNextRxBuffer ].addr &= ~( AT91C_OWNERSHIP_BIT );

		/* Increment to the next buffer, wrapping if necessary. */
		ulNextRxBuffer++;
		if( ulNextRxBuffer >= NB_RX_BUFFERS )
		{
			ulNextRxBuffer = 0;
		}
	}

	/* If we obtained data but for some reason did not find the end of the
	frame then discard the data as it must contain an error. */
	if( !ulEOF )
	{
		ulSectionLength = 0;
	}

	return ulSectionLength;
}
/*-----------------------------------------------------------*/

static void prvSetupDescriptors(void)
{
unsigned portBASE_TYPE xIndex;
unsigned portLONG ulAddress;

	/* Initialise xRxDescriptors descriptor. */
	for( xIndex = 0; xIndex < NB_RX_BUFFERS; ++xIndex )
	{
		/* Calculate the address of the nth buffer within the array. */
		ulAddress = ( unsigned portLONG )( pcRxBuffer + ( xIndex * ETH_RX_BUFFER_SIZE ) );

		/* Write the buffer address into the descriptor.  The DMA will place
		the data at this address when this descriptor is being used.  Mask off
		the bottom bits of the address as these have special meaning. */
		xRxDescriptors[ xIndex ].addr = ulAddress & emacADDRESS_MASK;
	}	

	/* The last buffer has the wrap bit set so the EMAC knows to wrap back
	to the first buffer. */
	xRxDescriptors[ NB_RX_BUFFERS - 1 ].addr |= emacRX_WRAP_BIT;

	/* Initialise xTxDescriptors. */
	for( xIndex = 0; xIndex < NB_TX_BUFFERS; ++xIndex )
	{
		/* Calculate the address of the nth buffer within the array. */
		ulAddress = ( unsigned portLONG )( pcTxBuffer + ( xIndex * ETH_TX_BUFFER_SIZE ) );

		/* Write the buffer address into the descriptor.  The DMA will read
		data from here when the descriptor is being used. */
		xTxDescriptors[ xIndex ].addr = ulAddress & emacADDRESS_MASK;
		xTxDescriptors[ xIndex ].U_Status.status = AT91C_TRANSMIT_OK;
	}	

	/* The last buffer has the wrap bit set so the EMAC knows to wrap back
	to the first buffer. */
	xTxDescriptors[ NB_TX_BUFFERS - 1 ].U_Status.status = AT91C_TRANSMIT_WRAP | AT91C_TRANSMIT_OK;

	/* Tell the EMAC where to find the descriptors. */
	AT91C_BASE_EMAC->EMAC_RBQP = ( unsigned portLONG ) xRxDescriptors;
	AT91C_BASE_EMAC->EMAC_TBQP = ( unsigned portLONG ) xTxDescriptors;
	
	/* Clear all the bits in the receive status register. */
	AT91C_BASE_EMAC->EMAC_RSR = ( AT91C_EMAC_OVR | AT91C_EMAC_REC | AT91C_EMAC_BNA );

	/* Enable the copy of data into the buffers, ignore broadcasts,
	and don't copy FCS. */
	AT91C_BASE_EMAC->EMAC_NCFGR |= ( AT91C_EMAC_CAF | AT91C_EMAC_NBC | AT91C_EMAC_DRFCS);

	/* Enable Rx and Tx, plus the stats register. */
	AT91C_BASE_EMAC->EMAC_NCR |= ( AT91C_EMAC_TE | AT91C_EMAC_RE | AT91C_EMAC_WESTAT );
}	
/*-----------------------------------------------------------*/

static void prvSetupMACAddress( void )
{
	/* Must be written SA1L then SA1H. */
	AT91C_BASE_EMAC->EMAC_SA1L =	( ( unsigned portLONG ) cMACAddress[ 3 ] << 24 ) |
									( ( unsigned portLONG ) cMACAddress[ 2 ] << 16 ) |
									( ( unsigned portLONG ) cMACAddress[ 1 ] << 8  ) |
									cMACAddress[ 0 ];

	AT91C_BASE_EMAC->EMAC_SA1H =	( ( unsigned portLONG ) cMACAddress[ 5 ] << 8 ) |
									cMACAddress[ 4 ];
}
/*-----------------------------------------------------------*/

static void prvSetupEMACInterrupt( void )
{
	/* Create the semaphore used to trigger the EMAC task. */
	vSemaphoreCreateBinary( xSemaphore );
	if( xSemaphore )
	{
		/* We start by 'taking' the semaphore so the ISR can 'give' it when the
		first interrupt occurs. */
		xSemaphoreTake( xSemaphore, emacNO_DELAY );
		portENTER_CRITICAL();
		{
			/* We want to interrupt on Rx events. */
			AT91C_BASE_EMAC->EMAC_IER = AT91C_EMAC_RCOMP;

			/* Enable the interrupts in the AIC. */
			AT91F_AIC_ConfigureIt( AT91C_BASE_AIC, AT91C_ID_EMAC, emacINTERRUPT_LEVEL, AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, ( void (*)( void ) ) vEMACISREntry );
			AT91F_AIC_EnableIt( AT91C_BASE_AIC, AT91C_ID_EMAC );
		}
		portEXIT_CRITICAL();
	}
}
/*-----------------------------------------------------------*/

__arm void vEMACISR( void )
{
volatile unsigned portLONG ulIntStatus, ulRxStatus;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	ulIntStatus = AT91C_BASE_EMAC->EMAC_ISR;
	ulRxStatus = AT91C_BASE_EMAC->EMAC_RSR;

	if( ( ulIntStatus & AT91C_EMAC_RCOMP ) || ( ulRxStatus & AT91C_EMAC_REC ) )
	{
		/* A frame has been received, signal the uIP task so it can process
		the Rx descriptors. */
		xSemaphoreGiveFromISR( xSemaphore, &xHigherPriorityTaskWoken );
		AT91C_BASE_EMAC->EMAC_RSR = AT91C_EMAC_REC;
	}

	/* If a task was woken by either a character being received or a character
	being transmitted then we may need to switch to another task. */
	portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );

	/* Clear the interrupt. */
	AT91C_BASE_AIC->AIC_EOICR = 0;
}
/*-----------------------------------------------------------*/



/*
 * The following functions are initialisation functions taken from the Atmel
 * EMAC sample code.
 */

static portBASE_TYPE prvProbePHY( void )
{
unsigned portLONG ulPHYId1, ulPHYId2, ulStatus;
portBASE_TYPE xReturn = pdPASS;
	
	/* Code supplied by Atmel (reformatted) -----------------*/

	/* Enable management port */
	AT91C_BASE_EMAC->EMAC_NCR |= AT91C_EMAC_MPE;	
	AT91C_BASE_EMAC->EMAC_NCFGR |= ( 2 ) << 10;

	/* Read the PHY ID. */
	vReadPHY( AT91C_PHY_ADDR, MII_PHYSID1, &ulPHYId1 );
	vReadPHY( AT91C_PHY_ADDR, MII_PHYSID2, &ulPHYId2 );

	/* AMD AM79C875:
			PHY_ID1 = 0x0022
			PHY_ID2 = 0x5541
			Bits 3:0 Revision Number Four bit manufacturer抯 revision number.
				0001 stands for Rev. A, etc.
	*/
	if( ( ( ulPHYId1 << 16 ) | ( ulPHYId2 & 0xfff0 ) ) != MII_DM9161_ID )
	{
		/* Did not expect this ID. */
		xReturn = pdFAIL;
	}
	else
	{
		ulStatus = xGetLinkSpeed();

		if( ulStatus != pdPASS )
		{
			xReturn = pdFAIL;
		}
	}

	/* Disable management port */
	AT91C_BASE_EMAC->EMAC_NCR &= ~AT91C_EMAC_MPE;	

	/* End of code supplied by Atmel ------------------------*/

	return xReturn;
}
/*-----------------------------------------------------------*/

static void vReadPHY( unsigned portCHAR ucPHYAddress, unsigned portCHAR ucAddress, unsigned portLONG *pulValue )
{
	/* Code supplied by Atmel (reformatted) ----------------------*/

	AT91C_BASE_EMAC->EMAC_MAN = 	(AT91C_EMAC_SOF & (0x01<<30))
									| (2 << 16) | (2 << 28)
									| ((ucPHYAddress & 0x1f) << 23)
									| (ucAddress << 18);

	/* Wait until IDLE bit in Network Status register is cleared. */
	while( !( AT91C_BASE_EMAC->EMAC_NSR & AT91C_EMAC_IDLE ) )
	{
		__asm( "NOP" );
	}

	*pulValue = ( AT91C_BASE_EMAC->EMAC_MAN & 0x0000ffff );	

	/* End of code supplied by Atmel ------------------------*/
}
/*-----------------------------------------------------------*/

#if USE_RMII_INTERFACE != 1
static void vWritePHY( unsigned portCHAR ucPHYAddress, unsigned portCHAR ucAddress, unsigned portLONG ulValue )
{
	/* Code supplied by Atmel (reformatted) ----------------------*/

	AT91C_BASE_EMAC->EMAC_MAN = (( AT91C_EMAC_SOF & (0x01<<30))
								| (2 << 16) | (1 << 28)
								| ((ucPHYAddress & 0x1f) << 23)
								| (ucAddress << 18))
								| (ulValue & 0xffff);

	/* Wait until IDLE bit in Network Status register is cleared */
	while( !( AT91C_BASE_EMAC->EMAC_NSR & AT91C_EMAC_IDLE ) )
	{
		__asm( "NOP" );
	};

	/* End of code supplied by Atmel ------------------------*/
}
#endif
/*-----------------------------------------------------------*/

static portBASE_TYPE xGetLinkSpeed( void )
{
	unsigned portLONG ulBMSR, ulBMCR, ulLPA, ulMACCfg, ulSpeed, ulDuplex;

	/* Code supplied by Atmel (reformatted) -----------------*/

	/* Link status is latched, so read twice to get current value */
	vReadPHY(AT91C_PHY_ADDR, MII_BMSR, &ulBMSR);
	vReadPHY(AT91C_PHY_ADDR, MII_BMSR, &ulBMSR);

	if( !( ulBMSR & BMSR_LSTATUS ) )
	{	
		/* No Link. */
		return pdFAIL;
	}

	vReadPHY(AT91C_PHY_ADDR, MII_BMCR, &ulBMCR);
	if (ulBMCR & BMCR_ANENABLE)
	{				
		/* AutoNegotiation is enabled. */
		if (!(ulBMSR & BMSR_ANEGCOMPLETE))
		{
			/* Auto-negotiation in progress. */
			return pdFAIL;				
		}		

		vReadPHY(AT91C_PHY_ADDR, MII_LPA, &ulLPA);
		if( ( ulLPA & LPA_100FULL ) || ( ulLPA & LPA_100HALF ) )
		{
			ulSpeed = SPEED_100;
		}
		else
		{
			ulSpeed = SPEED_10;
		}

		if( ( ulLPA & LPA_100FULL ) || ( ulLPA & LPA_10FULL ) )
		{
			ulDuplex = DUPLEX_FULL;
		}
		else
		{
			ulDuplex = DUPLEX_HALF;
		}
	}
	else
	{
		ulSpeed = ( ulBMCR & BMCR_SPEED100 ) ? SPEED_100 : SPEED_10;
		ulDuplex = ( ulBMCR & BMCR_FULLDPLX ) ? DUPLEX_FULL : DUPLEX_HALF;
	}

	/* Update the MAC */
	ulMACCfg = AT91C_BASE_EMAC->EMAC_NCFGR & ~( AT91C_EMAC_SPD | AT91C_EMAC_FD );
	if( ulSpeed == SPEED_100 )
	{
		if( ulDuplex == DUPLEX_FULL )
		{
			/* 100 Full Duplex */
			AT91C_BASE_EMAC->EMAC_NCFGR = ulMACCfg | AT91C_EMAC_SPD | AT91C_EMAC_FD;
		}
		else
		{					
			/* 100 Half Duplex */
			AT91C_BASE_EMAC->EMAC_NCFGR = ulMACCfg | AT91C_EMAC_SPD;
		}
	}
	else
	{
		if (ulDuplex == DUPLEX_FULL)
		{
			/* 10 Full Duplex */
			AT91C_BASE_EMAC->EMAC_NCFGR = ulMACCfg | AT91C_EMAC_FD;
		}
		else
		{
			/* 10 Half Duplex */
			AT91C_BASE_EMAC->EMAC_NCFGR = ulMACCfg;
		}
	}

	/* End of code supplied by Atmel ------------------------*/

	return pdPASS;
}