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/*

    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.

    ***************************************************************************

    *                                                                         *

    * If you are:                                                             *

    *                                                                         *

    *    + New to FreeRTOS,                                                   *

    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *

    *    + Looking for basic training,                                        *

    *    + Wanting to improve your FreeRTOS skills and productivity           *

    *                                                                         *

    * then take a look at the FreeRTOS books - available as PDF or paperback  *

    *                                                                         *

    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *

    *                  http://www.FreeRTOS.org/Documentation                  *

    *                                                                         *

    * A pdf reference manual is also available.  Both are usually delivered   *

    * to your inbox within 20 minutes to two hours when purchased between 8am *

    * and 8pm GMT (although please allow up to 24 hours in case of            *

    * exceptional circumstances).  Thank you for your support!                *

    *                                                                         *

    ***************************************************************************

    This file is part of the FreeRTOS distribution.

    FreeRTOS is free software; you can redistribute it and/or modify it under

    the terms of the GNU General Public License (version 2) as published by the

    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.

    ***NOTE*** The exception to the GPL is included to allow you to distribute

    a combined work that includes FreeRTOS without being obliged to provide the

    source code for proprietary components outside of the FreeRTOS kernel.

    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT

    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

    more details. You should have received a copy of the GNU General Public

    License and the FreeRTOS license exception along with FreeRTOS; if not it

    can be viewed here: http://www.freertos.org/a00114.html and also obtained

    by writing to Richard Barry, contact details for whom are available on the

    FreeRTOS WEB site.

    1 tab == 4 spaces!

    http://www.FreeRTOS.org - Documentation, latest information, license and

    contact details.

    http://www.SafeRTOS.com - A version that is certified for use in safety

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*/

/*

        Changes from V3.2.3

        + Modified char* types to compile without warning when using GCC V4.0.1.

        + Corrected the address to which the MAC address is written.  Thanks to

          Bill Knight for this correction.

        Changes from V3.2.4

        + Changed the default MAC address to something more realistic.

*/

/* Standard includes. */

#include <stdlib.h>

#include <string.h>

/* Scheduler include files. */

#include "FreeRTOS.h"

#include "task.h"

#include "semphr.h"

#include "tcp.h"

#include "serial.h"

/* Application includes. */

#include "i2c.h"

#include "html_pages.h"

/*-----------------------------------------------------------*/

/* Hardwired i2c address of the WIZNet device. */

#define tcpDEVICE_ADDRESS                               ( ( unsigned char ) 0x00 )

/* Constants used to configure the Tx and Rx buffer sizes within the WIZnet

device. */

#define tcp8K_RX                                                ( ( unsigned char ) 0x03 )

#define tcp8K_TX                                                ( ( unsigned char ) 0x03 )

/* Constants used to generate the WIZnet internal buffer addresses. */

#define tcpSINGLE_SOCKET_ADDR_MASK              ( ( unsigned long ) 0x1fff )

#define tcpSINGLE_SOCKET_ADDR_OFFSET    ( ( unsigned long ) 0x4000 )

/* Bit definitions of the commands that can be sent to the command register. */

#define tcpRESET_CMD                                    ( ( unsigned char ) 0x80 )

#define tcpSYS_INIT_CMD                                 ( ( unsigned char ) 0x01 )

#define tcpSOCK_STREAM                                  ( ( unsigned char ) 0x01 )

#define tcpSOCK_INIT                                    ( ( unsigned char ) 0x02 )

#define tcpLISTEN_CMD                                   ( ( unsigned char ) 0x08 )

#define tcpRECEIVE_CMD                                  ( ( unsigned char ) 0x40 )

#define tcpDISCONNECT_CMD                               ( ( unsigned char ) 0x10 )

#define tcpSEND_CMD                                             ( ( unsigned char ) 0x20 )

/* Constants required to handle the interrupts. */

#define tcpCLEAR_EINT0                                  ( 1 )

#define i2cCLEAR_ALL_INTERRUPTS                 ( ( unsigned char ) 0xff )

#define i2cCHANNEL_0_ISR_ENABLE                 ( ( unsigned char ) 0x01 )

#define i2cCHANNEL_0_ISR_DISABLE                ( ( unsigned char ) 0x00 )

#define tcpWAKE_ON_EINT0                                ( 1 )

#define tcpENABLE_EINT0_FUNCTION                ( ( unsigned long ) 0x01 )

#define tcpEINT0_VIC_CHANNEL_BIT                ( ( unsigned long ) 0x4000 )

#define tcpEINT0_VIC_CHANNEL                    ( ( unsigned long ) 14 )

#define tcpEINT0_VIC_ENABLE                             ( ( unsigned long ) 0x0020 )

/* Various delays used in the driver. */

#define tcpRESET_DELAY                                  ( ( portTickType ) 16 / portTICK_RATE_MS )

#define tcpINIT_DELAY                                   ( ( portTickType ) 500 / portTICK_RATE_MS  )

#define tcpLONG_DELAY                                   ( ( portTickType ) 500 / portTICK_RATE_MS  )

#define tcpSHORT_DELAY                                  ( ( portTickType ) 5 / portTICK_RATE_MS )

#define tcpCONNECTION_WAIT_DELAY                ( ( portTickType ) 100 / portTICK_RATE_MS )

#define tcpNO_DELAY                                             ( ( portTickType ) 0 )

/* Length of the data to read for various register reads. */

#define tcpSTATUS_READ_LEN                              ( ( unsigned long ) 1 )

#define tcpSHADOW_READ_LEN                              ( ( unsigned long ) 1 )

/* Register addresses within the WIZnet device. */

#define tcpCOMMAND_REG                                  ( ( unsigned short ) 0x0000 )

#define tcpGATEWAY_ADDR_REG                             ( ( unsigned short ) 0x0080 )

#define tcpSUBNET_MASK_REG                              ( ( unsigned short ) 0x0084 )

#define tcpSOURCE_HA_REG                                ( ( unsigned short ) 0x0088 )

#define tpcSOURCE_IP_REG                                ( ( unsigned short ) 0x008E )

#define tpcSOCKET_OPT_REG                               ( ( unsigned short ) 0x00A1 )

#define tcpSOURCE_PORT_REG                              ( ( unsigned short ) 0x00AE )

#define tcpTX_WRITE_POINTER_REG                 ( ( unsigned short ) 0x0040 )

#define tcpTX_READ_POINTER_REG                  ( ( unsigned short ) 0x0044 )

#define tcpTX_ACK_POINTER_REG                   ( ( unsigned short ) 0x0018 )

#define tcpTX_MEM_SIZE_REG                              ( ( unsigned short ) 0x0096 )

#define tcpRX_MEM_SIZE_REG                              ( ( unsigned short ) 0x0095 )

#define tcpINTERRUPT_STATUS_REG                 ( ( unsigned short ) 0x0004 )

#define tcpTX_WRITE_SHADOW_REG                  ( ( unsigned short ) 0x01F0 )

#define tcpTX_ACK_SHADOW_REG                    ( ( unsigned short ) 0x01E2 )

#define tcpISR_MASK_REG                                 ( ( unsigned short ) 0x0009 )

#define tcpINTERRUPT_REG                                ( ( unsigned short ) 0x0008 )

#define tcpSOCKET_STATE_REG                             ( ( unsigned short ) 0x00a0 )

/* Constants required for hardware setup. */

#define tcpRESET_ACTIVE_LOW                     ( ( unsigned long ) 0x20 )

#define tcpRESET_ACTIVE_HIGH                    ( ( unsigned long ) 0x10 )

/* Constants defining the source of the WIZnet ISR. */

#define tcpISR_SYS_INIT                                 ( ( unsigned char ) 0x01 )

#define tcpISR_SOCKET_INIT                              ( ( unsigned char ) 0x02 )

#define tcpISR_ESTABLISHED                              ( ( unsigned char ) 0x04 )

#define tcpISR_CLOSED                                   ( ( unsigned char ) 0x08 )

#define tcpISR_TIMEOUT                                  ( ( unsigned char ) 0x10 )

#define tcpISR_TX_COMPLETE                              ( ( unsigned char ) 0x20 )

#define tcpISR_RX_COMPLETE                              ( ( unsigned char ) 0x40 )

/* Constants defining the socket status bits. */

#define tcpSTATUS_ESTABLISHED                   ( ( unsigned char ) 0x06 )

#define tcpSTATUS_LISTEN                                ( ( unsigned char ) 0x02 )

/* Misc constants. */

#define tcpNO_STATUS_BITS                               ( ( unsigned char ) 0x00 )

#define i2cNO_ADDR_REQUIRED                             ( ( unsigned short ) 0x0000 )

#define i2cNO_DATA_REQUIRED                             ( 0x0000 )

#define tcpISR_QUEUE_LENGTH                             ( ( unsigned portBASE_TYPE ) 10 )

#define tcpISR_QUEUE_ITEM_SIZE                  ( ( unsigned portBASE_TYPE ) 0 )

#define tcpBUFFER_LEN                                   ( 4 * 1024 )

#define tcpMAX_REGISTER_LEN                             ( 4 )

#define tcpMAX_ATTEMPTS_TO_CHECK_BUFFER ( 6 )

#define tcpMAX_NON_LISTEN_STAUS_READS   ( 5 )

/* Message definitions.  The IP address, MAC address, gateway address, etc.

is set here! */

const unsigned char const ucDataGAR[]                           = { 172, 25, 218, 3 };  /* Gateway address. */

const unsigned char const ucDataMSR[]                           = { 255, 255, 255, 0 };  /* Subnet mask.         */

const unsigned char const ucDataSIPR[]                          = { 172, 25, 218, 201 };/* IP address.          */

const unsigned char const ucDataSHAR[]                          = { 00, 23, 30, 41, 15, 26 }; /* MAC address - DO NOT USE THIS ON A PUBLIC NETWORK! */

/* Other fixed messages. */

const unsigned char const ucDataReset[]                         = { tcpRESET_CMD };

const unsigned char const ucDataInit[]                          = { tcpSYS_INIT_CMD };

const unsigned char const ucDataProtocol[]                      = { tcpSOCK_STREAM };

const unsigned char const ucDataPort[]                          = { 0xBA, 0xCC };

const unsigned char const ucDataSockInit[]                      = { tcpSOCK_INIT };

const unsigned char const ucDataTxWritePointer[]        = { 0x11, 0x22, 0x00, 0x00 };

const unsigned char const ucDataTxAckPointer[]          = { 0x11, 0x22, 0x00, 0x00 };

const unsigned char const ucDataTxReadPointer[]         = { 0x11, 0x22, 0x00, 0x00 };

const unsigned char const ucDataListen[]                        = { tcpLISTEN_CMD };

const unsigned char const ucDataReceiveCmd[]            = { tcpRECEIVE_CMD };

const unsigned char const ucDataSetTxBufSize[]          = { tcp8K_TX };

const unsigned char const ucDataSetRxBufSize[]          = { tcp8K_RX };

const unsigned char const ucDataSend[]                          = { tcpSEND_CMD };

const unsigned char const ucDataDisconnect[]            = { tcpDISCONNECT_CMD };

const unsigned char const ucDataEnableISR[]                     = { i2cCHANNEL_0_ISR_ENABLE };

const unsigned char const ucDataDisableISR[]            = { i2cCHANNEL_0_ISR_DISABLE };

const unsigned char const ucDataClearInterrupt[]        = { i2cCLEAR_ALL_INTERRUPTS };

static xSemaphoreHandle xMessageComplete = NULL;

xQueueHandle xTCPISRQueue = NULL;

/* Dynamically generate and send an html page. */

static void prvSendSamplePage( void );

/* Read a register from the WIZnet device via the i2c interface. */

static void prvReadRegister( unsigned char *pucDestination, unsigned short usAddress, unsigned long ulLength );

/* Send the entire Tx buffer (the Tx buffer within the WIZnet device). */

static void prvFlushBuffer( unsigned long ulTxAddress );

/* Write a string to the WIZnet Tx buffer. */

static void prvWriteString( const char * const pucTxBuffer, long lTxLen, unsigned long *pulTxAddress );

/* Convert a number to a string. */

void ultoa( unsigned long ulVal, char *pcBuffer, long lIgnore );

/*-----------------------------------------------------------*/

void ultoa( unsigned long ulVal, char *pcBuffer, long lIgnore )

{

unsigned long lNibble;

long lIndex;

        /* Simple routine to convert an unsigned long value into a string in hex

        format. */

        /* For each nibble in the number we are converting. */

        for( lIndex = 0; lIndex < ( sizeof( ulVal ) * 2 ); lIndex++ )

        {

                /* Take the top four bits of the number. */

                lNibble = ( ulVal >> 28 );

                /* We are converting it to a hex string, so is the number in the range

                0-10 or A-F? */

                if( lNibble < 10 )

                {

                        pcBuffer[ lIndex ] = '0' + lNibble;

                }

                else

                {

                        lNibble -= 10;

                        pcBuffer[ lIndex ] = 'A' + lNibble;

                }

                /* Shift off the top nibble so we use the next nibble next time around. */

                ulVal <<= 4;

        }

        /* Mark the end of the string with a null terminator. */

        pcBuffer[ lIndex ] = 0x00;

}

/*-----------------------------------------------------------*/

static void prvReadRegister( unsigned char *pucDestination, unsigned short usAddress, unsigned long ulLength )

{

unsigned char ucRxBuffer[ tcpMAX_REGISTER_LEN ];

        /* Read a register value from the WIZnet device. */

        /* First write out the address of the register we want to read. */

        i2cMessage( ucRxBuffer, i2cNO_DATA_REQUIRED, tcpDEVICE_ADDRESS, usAddress, i2cWRITE, NULL, portMAX_DELAY );

        /* Then read back from that address. */

        i2cMessage( ( unsigned char * ) pucDestination, ulLength, tcpDEVICE_ADDRESS, i2cNO_ADDR_REQUIRED, i2cREAD, xMessageComplete, portMAX_DELAY );

        /* I2C messages are queued so use the semaphore to wait for the read to

        complete - otherwise we will leave this function before the I2C

        transactions have completed. */

        xSemaphoreTake( xMessageComplete, tcpLONG_DELAY );

}

/*-----------------------------------------------------------*/

void vTCPHardReset( void )

{

        /* Physical reset of the WIZnet device by using the GPIO lines to hold the

        WIZnet reset lines active for a few milliseconds. */

        /* Make sure the interrupt from the WIZnet is disabled. */

        VICIntEnClear |= tcpEINT0_VIC_CHANNEL_BIT;

        /* If xMessageComplete is NULL then this is the first time that this

        function has been called and the queue and semaphore used in this file

        have not yet been created. */

        if( xMessageComplete == NULL )

        {

                /* Create and obtain the semaphore used when we want to wait for an i2c

                message to be completed. */

                vSemaphoreCreateBinary( xMessageComplete );

                xSemaphoreTake( xMessageComplete, tcpNO_DELAY );

                /* Create the queue used to communicate between the WIZnet and TCP tasks. */

                xTCPISRQueue = xQueueCreate( tcpISR_QUEUE_LENGTH, tcpISR_QUEUE_ITEM_SIZE );

        }

        /* Use the GPIO to reset the network hardware. */

        GPIO_IOCLR = tcpRESET_ACTIVE_LOW;

        GPIO_IOSET = tcpRESET_ACTIVE_HIGH;

        /* Delay with the network hardware in reset for a short while. */

        vTaskDelay( tcpRESET_DELAY );

        GPIO_IOCLR = tcpRESET_ACTIVE_HIGH;

        GPIO_IOSET = tcpRESET_ACTIVE_LOW;

        vTaskDelay( tcpINIT_DELAY );

        /* Setup the EINT0 to interrupt on required events from the WIZnet device.

        First enable the EINT0 function of the pin. */

        PCB_PINSEL1 |= tcpENABLE_EINT0_FUNCTION;

        /* We want the TCP comms to wake us from power save. */

        SCB_EXTWAKE = tcpWAKE_ON_EINT0;

        /* Install the ISR into the VIC - but don't enable it yet! */

        portENTER_CRITICAL();

        {

                extern void ( vEINT0_ISR_Wrapper )( void );

                VICIntSelect &= ~( tcpEINT0_VIC_CHANNEL_BIT );

                VICVectAddr3 = ( long ) vEINT0_ISR_Wrapper;

                VICVectCntl3 = tcpEINT0_VIC_CHANNEL | tcpEINT0_VIC_ENABLE;

        }

        portEXIT_CRITICAL();

        /* Enable interrupts in the WIZnet itself. */

        i2cMessage( ucDataEnableISR, sizeof( ucDataEnableISR ), tcpDEVICE_ADDRESS, tcpISR_MASK_REG, i2cWRITE, NULL, portMAX_DELAY );

        vTaskDelay( tcpLONG_DELAY );

}

/*-----------------------------------------------------------*/

long lTCPSoftReset( void )

{

unsigned char ucStatus;

extern volatile long lTransactionCompleted;

        /* Send a message to the WIZnet device to tell it set all it's registers

        back to their default states.  Then setup the WIZnet device as required. */

        /* Reset the internal WIZnet registers. */

        i2cMessage( ucDataReset,        sizeof( ucDataReset ),  tcpDEVICE_ADDRESS, tcpCOMMAND_REG, i2cWRITE, NULL, portMAX_DELAY );

        /* Now we can configure the protocol.   Here the MAC address, gateway

        address, subnet mask and IP address are configured. */

        i2cMessage( ucDataSHAR,         sizeof( ucDataSHAR ),   tcpDEVICE_ADDRESS, tcpSOURCE_HA_REG, i2cWRITE, NULL, portMAX_DELAY );

        i2cMessage( ucDataGAR,          sizeof( ucDataGAR ),    tcpDEVICE_ADDRESS, tcpGATEWAY_ADDR_REG, i2cWRITE, NULL, portMAX_DELAY );

        i2cMessage( ucDataMSR,          sizeof( ucDataMSR ),    tcpDEVICE_ADDRESS, tcpSUBNET_MASK_REG,  i2cWRITE, NULL, portMAX_DELAY );

        i2cMessage( ucDataSIPR,         sizeof( ucDataSIPR ),   tcpDEVICE_ADDRESS, tpcSOURCE_IP_REG,    i2cWRITE, NULL, portMAX_DELAY );

        /* Next the memory buffers are configured to give all the WIZnet internal

        memory over to a single socket.  This gives the socket the maximum internal

        Tx and Rx buffer space. */

        i2cMessage( ucDataSetTxBufSize, sizeof( ucDataSetTxBufSize ), tcpDEVICE_ADDRESS, tcpTX_MEM_SIZE_REG, i2cWRITE, NULL, portMAX_DELAY );

        i2cMessage( ucDataSetRxBufSize, sizeof( ucDataSetRxBufSize ), tcpDEVICE_ADDRESS, tcpRX_MEM_SIZE_REG, i2cWRITE, NULL, portMAX_DELAY );

        /* Send the sys init command so the above parameters take effect. */

        i2cMessage( ucDataInit,         sizeof( ucDataInit ),   tcpDEVICE_ADDRESS, tcpCOMMAND_REG, i2cWRITE, NULL, portMAX_DELAY );

        /* Seems to like a little wait here. */

        vTaskDelay( tcpINIT_DELAY );

        /* Read back the status to ensure the system initialised ok. */

        prvReadRegister( &ucStatus, tcpINTERRUPT_STATUS_REG, tcpSTATUS_READ_LEN );

        /* We should find that the sys init was successful. */

        if( ucStatus != tcpISR_SYS_INIT )

        {

                return ( long ) pdFAIL;

        }

        /* No i2c errors yet. */

        portENTER_CRITICAL();

                lTransactionCompleted = pdTRUE;

        portEXIT_CRITICAL();

        return ( long ) pdPASS;

}

/*-----------------------------------------------------------*/

long lTCPCreateSocket( void )

{

unsigned char ucStatus;

        /* Create and configure a socket. */

        /* Setup and init the socket.  Here the port number is set and the socket

        is initialised. */

        i2cMessage( ucDataProtocol, sizeof( ucDataProtocol),tcpDEVICE_ADDRESS, tpcSOCKET_OPT_REG, i2cWRITE, NULL, portMAX_DELAY );

        i2cMessage( ucDataPort,         sizeof( ucDataPort),    tcpDEVICE_ADDRESS, tcpSOURCE_PORT_REG, i2cWRITE, NULL, portMAX_DELAY );

        i2cMessage( ucDataSockInit, sizeof( ucDataSockInit),tcpDEVICE_ADDRESS, tcpCOMMAND_REG, i2cWRITE, xMessageComplete, portMAX_DELAY );

        /* Wait for the Init command to be sent. */

        if( !xSemaphoreTake( xMessageComplete, tcpLONG_DELAY ) )

        {

                /* For some reason the message was not transmitted within our block

                period. */

                return ( long ) pdFAIL;

        }

        /* Allow the socket to initialise. */

        vTaskDelay( tcpINIT_DELAY );

        /* Read back the status to ensure the socket initialised ok. */

        prvReadRegister( &ucStatus, tcpINTERRUPT_STATUS_REG, tcpSTATUS_READ_LEN );

        /* We should find that the socket init was successful. */

        if( ucStatus != tcpISR_SOCKET_INIT )

        {

                return ( long ) pdFAIL;

        }

        /* Setup the Tx pointer registers to indicate that the Tx buffer is empty. */

        i2cMessage( ucDataTxReadPointer, sizeof( ucDataTxReadPointer ), tcpDEVICE_ADDRESS, tcpTX_READ_POINTER_REG, i2cWRITE, NULL, portMAX_DELAY );

        vTaskDelay( tcpSHORT_DELAY );

        i2cMessage( ucDataTxWritePointer, sizeof( ucDataTxWritePointer ), tcpDEVICE_ADDRESS, tcpTX_WRITE_POINTER_REG, i2cWRITE, NULL, portMAX_DELAY );

        vTaskDelay( tcpSHORT_DELAY );

        i2cMessage( ucDataTxAckPointer,   sizeof( ucDataTxAckPointer ),   tcpDEVICE_ADDRESS, tcpTX_ACK_POINTER_REG, i2cWRITE, NULL, portMAX_DELAY );

        vTaskDelay( tcpSHORT_DELAY );

        return ( long ) pdPASS;

}

/*-----------------------------------------------------------*/

void vTCPListen( void )

{

unsigned char ucISR;

        /* Start a passive listen on the socket. */

        /* Enable interrupts in the WizNet device after ensuring none are

        currently pending. */

        while( SCB_EXTINT & tcpCLEAR_EINT0 )

        {

                /* The WIZnet device is still asserting and interrupt so tell it to

                clear. */

                i2cMessage( ucDataClearInterrupt, sizeof( ucDataClearInterrupt ), tcpDEVICE_ADDRESS, tcpINTERRUPT_REG, i2cWRITE, xMessageComplete, portMAX_DELAY );

                xSemaphoreTake( xMessageComplete, tcpLONG_DELAY );

                vTaskDelay( 1 );

                SCB_EXTINT = tcpCLEAR_EINT0;

        }

        while( xQueueReceive( xTCPISRQueue, &ucISR, tcpNO_DELAY ) )

        {

                /* Just clearing the queue used by the ISR routine to tell this task

                that the WIZnet device needs attention. */

        }

        /* Now all the pending interrupts have been cleared we can enable the

        processor interrupts. */

        VICIntEnable |= tcpEINT0_VIC_CHANNEL_BIT;

        /* Then start listening for incoming connections. */

        i2cMessage( ucDataListen, sizeof( ucDataListen ), tcpDEVICE_ADDRESS, tcpCOMMAND_REG, i2cWRITE, NULL, portMAX_DELAY );

}

/*-----------------------------------------------------------*/

long lProcessConnection( void )

{

unsigned char ucISR, ucState, ucLastState = 2, ucShadow;

extern volatile long lTransactionCompleted;

long lSameStateCount = 0, lDataSent = pdFALSE;

unsigned long ulWritePointer, ulAckPointer;

        /* No I2C errors can yet have occurred. */

        portENTER_CRITICAL();

                lTransactionCompleted = pdTRUE;

        portEXIT_CRITICAL();

        /* Keep looping - processing interrupts, until we have completed a

        transaction.   This uses the WIZnet in it's simplest form.  The socket

        accepts a connection - we process the connection - then close the socket.

        We then go back to reinitialise everything and start again. */

        while( lTransactionCompleted == pdTRUE )

        {

                /* Wait for a message on the queue from the WIZnet ISR.  When the

                WIZnet device asserts an interrupt the ISR simply posts a message

                onto this queue to wake this task. */

                if( xQueueReceive( xTCPISRQueue, &ucISR, tcpCONNECTION_WAIT_DELAY ) )

                {

                        /* The ISR posted a message on this queue to tell us that the

                        WIZnet device asserted an interrupt.  The ISR cannot process

                        an I2C message so cannot tell us what caused the interrupt so

                        we have to query the device here.  This task is the highest

                        priority in the system so will run immediately following the ISR. */

                        prvReadRegister( &ucISR, tcpINTERRUPT_STATUS_REG, tcpSTATUS_READ_LEN );

                        /* Once we have read what caused the ISR we can clear the interrupt

                        in the WIZnet. */

                        i2cMessage( ucDataClearInterrupt, sizeof( ucDataClearInterrupt ), tcpDEVICE_ADDRESS, tcpINTERRUPT_REG, i2cWRITE, NULL, portMAX_DELAY );

                        /* Now we can clear the processor interrupt and re-enable ready for

                        the next. */

                        SCB_EXTINT = tcpCLEAR_EINT0;

                        VICIntEnable |= tcpEINT0_VIC_CHANNEL_BIT;

                        /* Process the interrupt ... */

                        if( ucISR & tcpISR_ESTABLISHED )

                        {

                                /* A connection has been established - respond by sending

                                a receive command. */

                                i2cMessage( ucDataReceiveCmd, sizeof( ucDataReceiveCmd ), tcpDEVICE_ADDRESS, tcpCOMMAND_REG, i2cWRITE, NULL, portMAX_DELAY );

                        }

                        if( ucISR & tcpISR_RX_COMPLETE )

                        {

                                /* We message has been received.  This will be an HTTP get

                                command.  We only have one page to send so just send it without

                                regard to what the actual requested page was. */

                                prvSendSamplePage();

                        }

                        if( ucISR & tcpISR_TX_COMPLETE )

                        {

                                /* We have a TX complete interrupt - which oddly does not

                                indicate that the message being sent is complete so we cannot

                                yet close the socket.  Instead we read the position of the Tx

                                pointer within the WIZnet device so we know how much data it

                                has to send.  Later we will read the ack pointer and compare

                                this to the Tx pointer to ascertain whether the transmission

                                has completed. */

                                /* First read the shadow register. */

                                prvReadRegister( &ucShadow, tcpTX_WRITE_SHADOW_REG, tcpSHADOW_READ_LEN );

                                /* Now a short delay is required. */

                                vTaskDelay( tcpSHORT_DELAY );

                                /* Then we can read the real register. */

                                prvReadRegister( ( unsigned char * ) &ulWritePointer, tcpTX_WRITE_POINTER_REG, sizeof( ulWritePointer ) );

                                /* We cannot do anything more here but need to remember that

                                this interrupt has occurred. */

                                lDataSent = pdTRUE;

                        }

                        if( ucISR & tcpISR_CLOSED )

                        {

                                /* The socket has been closed so we can leave this function. */

                                lTransactionCompleted = pdFALSE;

                        }

                }

                else

                {

                        /* We have not received an interrupt from the WIZnet device for a

                        while.  Read the socket status and check that everything is as

                        expected. */

                        prvReadRegister( &ucState, tcpSOCKET_STATE_REG, tcpSTATUS_READ_LEN );

                        if( ( ucState == tcpSTATUS_ESTABLISHED ) && ( lDataSent > 0 ) )

                        {

                                /* The socket is established and we have already received a Tx

                                end interrupt.  We must therefore be waiting for the Tx buffer

                                inside the WIZnet device to be empty before we can close the

                                socket.

                                Read the Ack pointer register to see if it has caught up with

                                the Tx pointer register.  First we have to read the shadow

                                register. */

                                prvReadRegister( &ucShadow, tcpTX_ACK_SHADOW_REG, tcpSHADOW_READ_LEN );

                                vTaskDelay( tcpSHORT_DELAY );

                                prvReadRegister( ( unsigned char * ) &ulAckPointer, tcpTX_ACK_POINTER_REG, sizeof( ulWritePointer ) );

                                if( ulAckPointer == ulWritePointer )

                                {

                                        /* The Ack and write pointer are now equal and we can

                                        safely close the socket. */

                                        i2cMessage( ucDataDisconnect, sizeof( ucDataDisconnect ), tcpDEVICE_ADDRESS, tcpCOMMAND_REG, i2cWRITE, NULL, portMAX_DELAY );

                                }

                                else

                                {

                                        /* Keep a count of how many times we encounter the Tx

                                        buffer still containing data. */

                                        lDataSent++;

                                        if( lDataSent > tcpMAX_ATTEMPTS_TO_CHECK_BUFFER )

                                        {

                                                /* Assume we cannot complete sending the data and

                                                therefore cannot safely close the socket.  Start over. */

                                                vTCPHardReset();

                                                lTransactionCompleted = pdFALSE;

                                        }

                                }

                        }

                        else if( ucState != tcpSTATUS_LISTEN )

                        {

                                /* If we have not yet received a Tx end interrupt we would only

                                ever expect to find the socket still listening for any

                                sustained period. */

                                if( ucState == ucLastState )

                                {

                                        lSameStateCount++;

                                        if( lSameStateCount > tcpMAX_NON_LISTEN_STAUS_READS )

                                        {

                                                /* We are persistently in an unexpected state.  Assume

                                                we cannot safely close the socket and start over. */

                                                vTCPHardReset();

                                                lTransactionCompleted = pdFALSE;

                                        }

                                }

                        }

                        else

                        {

                                /* We are in the listen state so are happy that everything

                                is as expected. */

                                lSameStateCount = 0;

                        }

                        /* Remember what state we are in this time around so we can check

                        for a persistence on an unexpected state. */

                        ucLastState = ucState;

                }

        }

        /* We are going to reinitialise the WIZnet device so do not want our

        interrupts from the WIZnet to be processed. */

        VICIntEnClear |= tcpEINT0_VIC_CHANNEL_BIT;

        return lTransactionCompleted;

}

/*-----------------------------------------------------------*/

static void prvWriteString( const char * const pucTxBuffer, long lTxLen, unsigned long *pulTxAddress )

{

unsigned long ulSendAddress;

        /* Send a string to the Tx buffer internal to the WIZnet device. */

        /* Calculate the address to which we are going to write in the buffer. */

        ulSendAddress = ( *pulTxAddress & tcpSINGLE_SOCKET_ADDR_MASK ) + tcpSINGLE_SOCKET_ADDR_OFFSET;

        /* Send the buffer to the calculated address.  Use the semaphore so we

        can wait until the entire message has been transferred. */

        i2cMessage( ( unsigned char * ) pucTxBuffer, lTxLen, tcpDEVICE_ADDRESS, ( unsigned short ) ulSendAddress, i2cWRITE, xMessageComplete, portMAX_DELAY );

        /* Wait until the semaphore indicates that the message has been transferred. */

        if( !xSemaphoreTake( xMessageComplete, tcpLONG_DELAY ) )

        {

                return;

        }

        /* Return the new address of the end of the buffer (within the WIZnet

        device). */

        *pulTxAddress += ( unsigned long ) lTxLen;

}

/*-----------------------------------------------------------*/

static void prvFlushBuffer( unsigned long ulTxAddress )

{

unsigned char ucTxBuffer[ tcpMAX_REGISTER_LEN ];

        /* We have written some data to the Tx buffer internal to the WIZnet

        device.  Now we update the Tx pointer inside the WIZnet then send a

        Send command - which causes     the data up to the new Tx pointer to be

        transmitted. */

        /* Make sure endieness is correct for transmission. */

        ulTxAddress = htonl( ulTxAddress );

        /* Place the new Tx pointer in the string to be transmitted. */

        ucTxBuffer[ 0 ] = ( unsigned char ) ( ulTxAddress & 0xff );

        ulTxAddress >>= 8;

        ucTxBuffer[ 1 ] = ( unsigned char ) ( ulTxAddress & 0xff );

        ulTxAddress >>= 8;

        ucTxBuffer[ 2 ] = ( unsigned char ) ( ulTxAddress & 0xff );

        ulTxAddress >>= 8;

        ucTxBuffer[ 3 ] = ( unsigned char ) ( ulTxAddress & 0xff );

        ulTxAddress >>= 8;

        /* And send it to the WIZnet device. */

        i2cMessage( ucTxBuffer, sizeof( ulTxAddress ), tcpDEVICE_ADDRESS, tcpTX_WRITE_POINTER_REG, i2cWRITE, xMessageComplete, portMAX_DELAY );

        if( !xSemaphoreTake( xMessageComplete, tcpLONG_DELAY ) )

        {

                return;

        }

        vTaskDelay( tcpSHORT_DELAY );

        /* Transmit! */

        i2cMessage( ucDataSend, sizeof( ucDataSend ), tcpDEVICE_ADDRESS, tcpCOMMAND_REG, i2cWRITE, xMessageComplete, portMAX_DELAY );

        if( !xSemaphoreTake( xMessageComplete, tcpLONG_DELAY ) )

        {

                return;

        }

}

/*-----------------------------------------------------------*/

static void prvSendSamplePage( void )

{

extern long lErrorInTask;

unsigned long ulTxAddress;

unsigned char ucShadow;

long lIndex;

static unsigned long ulRefreshCount = 0x00;

static char cPageBuffer[ tcpBUFFER_LEN ];

        /* This function just generates a sample page of HTML which gets

        sent each time a client attaches to the socket.  The page is created

        from two fixed strings (cSamplePageFirstPart and cSamplePageSecondPart)

        with a bit of dynamically generated data in the middle. */

        /* We need to know the address to which the html string should be sent

        in the WIZnet Tx buffer.  First read the shadow register. */

        prvReadRegister( &ucShadow, tcpTX_WRITE_SHADOW_REG, tcpSHADOW_READ_LEN );

        /* Now a short delay is required. */