CCS/EK-TM4C123GXL: Trouble reading data from external temp sensor

Tool/software: Code Composer Studio

Hi!

i am attempting to read a temperature from the temp/humidty sensor HTU21D-F and I am not receiving any data. I am stuck as to what i should focus on to resolve this issue. any hints/help would be awesome. when i run my code, regardless if the temp sensor is connected i get -52.3299 as "tempf" and 1.0842E-19 for "temp". 

thanks,

- lucas

here is my code

/**************************************************Temp code for SHT21************************************************/

/* Libraries*/
#include <stdbool.h>
#include <stdint.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"
#include "utils/uartstdio.h"
#include "inc/hw_i2c.h"
#include "driverlib/i2c.h"
#include "inc/hw_ints.h"
#include "driverlib/interrupt.h"
#include "driverlib/timer.h"
#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "driverlib/debug.h"
#include "driverlib/pwm.h"
#include "driverlib/pin_map.h"
#include "inc/hw_gpio.h"
#include "driverlib/rom.h"

/***************Temp Sensor Driver Library*********************************/

#include "sensorlib/hw_sht21.h"
#include "sensorlib/i2cm_drv.h"
#include "sensorlib/sht21.h"
#include "inc/hw_ints.h"
#include "driverlib/debug.h"
#include "driverlib/rom.h"
#include "driverlib/rom_map.h"

/*************************************************************************************************************************************/

#define SHT21_I2C_ADDRESS 0x40 // temperature sensor address
#define SHT21_TEMP_NOBLOCK 0xF3 // Value to send to read Temperature from Sensor

#define ST_CTRL_R (*((volatile unsigned long *)0xE000E010))
#define ST_RELOAD_R (*((volatile unsigned long *)0xE000E014))
#define ST_CURRENT_R (*((volatile unsigned long *)0xE000E018))

uint32_t ui32SysClkFreq; //global variable for clock
static uint32_t g_I2C0Data[3]; // Data byte gathered from I2C3 master
void Configurei2C0(); // Function for I2C setup
void LED();

void Slave_Setup();
void SysTick_Init(void);

float tempf;
float temp;

void main(void) {

SysCtlClockSet(SYSCTL_SYSDIV_5|SYSCTL_USE_PLL|SYSCTL_OSC_MAIN|SYSCTL_XTAL_16MHZ);

ui32SysClkFreq = SysCtlClockGet();

LED();
SysTick_Init();

Configurei2C0();

/*********************I2C Slave setup***************************/

while (1) {

SysCtlDelay(20000);

I2CMasterInitExpClk(I2C0_BASE, ui32SysClkFreq, false); // The False sets the controller to 100kHz communication
//Setup_i2C();

I2CMasterSlaveAddrSet(I2C0_BASE, SHT21_I2C_ADDRESS, false); //Setup Slave and send Temp address
SysCtlDelay(20000);
I2CMasterDataPut(I2C0_BASE, 0xFE); // Soft Reset
SysCtlDelay(20000);
I2CMasterDataPut(I2C0_BASE, SHT21_TEMP_NOBLOCK); //Send Temp read info
SysCtlDelay(20000);
I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_SEND); //Setup I2c master for single send
SysCtlDelay(20000);

// Set address to read
I2CMasterSlaveAddrSet(I2C0_BASE, SHT21_I2C_ADDRESS, true);
SysCtlDelay(50000);
// Master read data byte 1 and store
I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);
SysCtlDelay(20000);
g_I2C0Data[0] = I2CMasterDataGet(I2C0_BASE);
SysCtlDelay(50000);
// Master read data byte 2 and store
I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);
SysCtlDelay(50000);
g_I2C0Data[1] = I2CMasterDataGet(I2C0_BASE);
SysCtlDelay(50000);
// Master read data byte 3 (checksum) and store
I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);
SysCtlDelay(50000);

//Convert to temperature
uint32_t tempConvert = ((uint32_t) g_I2C0Data[0] << 8)| (uint32_t) (g_I2C0Data[1]);
SysCtlDelay(50000);

float temp = (float) (tempConvert & 0xFFFC); //------this is when a number stops for "temp"
SysCtlDelay(50000);

temp = -46.85f + 175.72f * (temp / 65536.0f);
tempf = temp*(9.0f/5.0f)+32;

SysCtlDelay(50000);

if (temp < 50.00f) {

GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6, 0x40);

}

else if (temp > 50.00f) {

GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6, 0x00);

}
}
}

// Function definitions ************************************************************************************************************************************

void Configurei2C0(void) {
SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C0); // Enable I2C hardware
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB); // Enable Pin hardware

GPIOPinConfigure(GPIO_PB3_I2C0SDA); // Configure GPIO pin for I2C Data line
GPIOPinConfigure(GPIO_PB2_I2C0SCL); // Configure GPIO Pin for I2C clock line

GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_2 | GPIO_PIN_3); // Set Pin Type

GPIOPadConfigSet(GPIO_PORTB_BASE, GPIO_PIN_2, GPIO_STRENGTH_2MA,
GPIO_PIN_TYPE_STD); // SDA MUST BE STD
GPIOPadConfigSet(GPIO_PORTB_BASE, GPIO_PIN_3, GPIO_STRENGTH_2MA,
GPIO_PIN_TYPE_STD);

I2CMasterInitExpClk(I2C0_BASE, ui32SysClkFreq, false); // The False sets the controller to 100kHz communication

}

void LED(void) {

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
GPIOPinTypeGPIOOutput(GPIO_PORTA_BASE, GPIO_PIN_6);

}

void SysTick_Init(void) // Initialize SysTick running at bus clock.
{
ST_CTRL_R = 0; // disable SysTick during setup
ST_RELOAD_R = 0x00ffffff; // set maximum reload value
ST_CURRENT_R = 0; // any write to current clears it
// enable SysTick (write 1 to bit 0), turn off interupts (0 to bit 1), use core clock (1 to bit2)
ST_CTRL_R = 0x05;
}