RTOS/CC2650STK: HDC1000 (Humidity Sensor) not working on SensorTag

Tool/software: TI-RTOS

Hi,

I am unable to communicate via i2c to the humidity sensor on the SensorTag. I have successfully got communications flowing with the accelerometer, infrared sensor, pressure sensor and light sensor. I have tried this code with two different sensortags and two different debuggers (XDS110 DEVPACK), so I dont think it is the hardware to blame.

The following code was based on the i2ctmp007_CC2650STK_TI example project. the only lines changed are: 

txBuffer[0] = 0xfe

i2cTransaction.slaveAddress = Board_HDC1000_ADDR; /* 0x43 */

Here is a sample of the file involving the i2c communications function.

#define MANUFACTURER_REG 0xfe

Void taskFxn(UArg arg0, UArg arg1)
{
    uint16_t        id;
    uint8_t         txBuffer[1];
    uint8_t         rxBuffer[2];
    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);
    if (i2c == NULL) {
        System_abort("Error Initializing I2C\n");
    }
    else {
        System_printf("I2C Initialized!\n");
    }

    /* Point to the T ambient register and read its 2 bytes */
    txBuffer[0] = MANUFACTURER_REG; /* 0xfe */
    i2cTransaction.slaveAddress = Board_HDC1000_ADDR; /* 0x43 */
    i2cTransaction.writeBuf = txBuffer;
    i2cTransaction.writeCount = 1;
    i2cTransaction.readBuf = rxBuffer;
    i2cTransaction.readCount = 2;


    if (I2C_transfer(i2c, &i2cTransaction)) {
        /* Extract degrees C from the received data; see TMP102 datasheet */
        id = (rxBuffer[0] << 8) | rxBuffer[1];

        System_printf("ID %d\n", id);
    }
    else {
        System_printf("I2C Bus fault\n");
    }

    /* Deinitialized I2C */
    I2C_close(i2c);
    System_printf("I2C closed!\n");
    System_flush();
}

The output of this program is:

I2C Initialized!
I2C Bus fault
I2C closed!

Any ideas ?