RTOS/TM4C123GH6PM: Not Able to Communicate With I2C

/*
 * Copyright (c) 2015, Texas Instruments Incorporated
 * All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
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 *
 * *  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 * *  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * *  Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 *    ======== i2ctmp006.c ========
 */

/* XDCtools Header files */
#include <xdc/std.h>
#include <xdc/runtime/System.h>

/* BIOS Header files */
#include <ti/sysbios/BIOS.h>
#include <ti/sysbios/knl/Task.h>

/* TI-RTOS Header files */
#include <ti/drivers/GPIO.h>
#include <ti/drivers/I2C.h>

/* Example/Board Header files */
#include "Board.h"
#include "pixy_header.h"

#define TASKSTACKSIZE       640

Task_Struct task0Struct;
char task0Stack[TASKSTACKSIZE];
/*
int count = 0;
void gpioButtonFxn0(unsigned int index)
{
     Clear the GPIO interrupt and toggle an LED
   GPIO_toggle(Board_LED0);

    if (count++ == 100) {
        count = 0;
    }
}
*/

uint8_t getByte()
{

    uint8_t         txBuffer[1];
    uint8_t         rxBuffer[1];
    I2C_Handle      i2c;
    I2C_Params      i2cParams;
    I2C_Transaction i2cTransaction;

    /* Create I2C for usage */
    I2C_Params_init(&i2cParams);
    i2cParams.bitRate = I2C_400kHz;
    i2c = I2C_open(Board_I2C_TMP, &i2cParams);
    txBuffer[0] = 0x00;
    i2cTransaction.slaveAddress = Board_PIXY_ADDR;
    i2cTransaction.writeBuf = txBuffer;
    i2cTransaction.writeCount = 0;
    i2cTransaction.readBuf = rxBuffer;
    i2cTransaction.readCount = 1;

    I2C_transfer(i2c, &i2cTransaction);
     /* Deinitialized I2C */
     I2C_close(i2c);
     return rxBuffer[0];
}


/*
 *  ======== taskFxn ========
 *  Task for this function is created statically. See the project's .cfg file.
 */

void taskFxn(UArg arg0, UArg arg1)
{
        int i;
        uint8_t prev = 0;
        int maxblock = 100;
        /* Turn on user LED */
           GPIO_write(Board_LED1, Board_LED_ON);   //Green
           for(i=1000;i>0;i--);
           GPIO_write(Board_LED1, Board_LED_OFF);
           for(i=1000;i>0;i--);
        while(1)
        {
            getStart();
            int ret = getBlocks(maxblock);
            for(i=0;i<ret;i++)
            {
              int color = g_blocks[i].signature;
                if ( prev != color )
                {
                    switch(color)
                    {
                    case 1 : //printf("Green\n");
                             GPIO_write(Board_LED1, Board_LED_ON); //Green LED
                        break;
                    case 2 : // printf("Orange\n");
                             GPIO_write(Board_LED2, Board_LED_ON); //Red LED
                        break;
                    case 3 : //printf("Yellow\n");
                               GPIO_write(Board_LED0, Board_LED_ON); //Blue LED
                        break;
                    }
                }
                prev = color;
                //Task_sleep(100);
               }
          }

}

void taskFxn_1(UArg arg0, UArg arg1)
{
    int i;
    while(1){
    GPIO_write(Board_LED1, Board_LED_ON);   //Green
    for(i=1000000;i>0;i--);
    GPIO_write(Board_LED1, Board_LED_OFF);
    for(i=1000000;i>0;i--);
    }
}

/*
 *  ======== main ========
 */
int main(void)
{
   // int i;
    Task_Params taskParams;
    System_printf("Inside I2C Example\n");

    /* Call board init functions */
    Board_initGeneral();
    Board_initGPIO();
    Board_initI2C();
    init();

    /* Construct tmp006 Task thread */
    Task_Params_init(&taskParams);
    taskParams.stackSize = TASKSTACKSIZE;
    taskParams.stack = &task0Stack;
    Task_construct(&task0Struct, (Task_FuncPtr)taskFxn, &taskParams, NULL);


//    GPIO_write(Board_LED0, Board_LED_ON);   //blue

    System_printf("Starting the I2C example\nSystem provider is set to SysMin."
                  " Halt the target to view any SysMin contents in ROV.\n");
    /* SysMin will only print to the console when you call flush or exit */
    System_flush();
#if 0
    /* install Button callback */
       GPIO_setCallback(Board_BUTTON0, gpioButtonFxn0);

       /* Enable interrupts */
       GPIO_enableInt(Board_BUTTON0);
#endif


    /* Start BIOS */
    BIOS_start();

    return (0);
}