TM4C123GH6PM: LoRa interfacing with tiva C series microcontroller

Greetings,

I was facing an issue when interfacing Lora module RN2483 of microchip over UART communication.

The lux variable when i am directly feeding the data into it its successfully getting transmitted in HEX format while I am trying to transmit fAmbient data which changes upon every sample collected over I2C bus. The which i am receiving on the other end is 0 .

I am pasting the code down below please help.

#include <stdint.h>
#include <string.h>
#include <stdbool.h>
#include <string.h>
#include "inc/hw_memmap.h"
#include "inc/hw_ints.h"
#include "driverlib/debug.h"
#include "driverlib/gpio.h"
#include "driverlib/adc.h"
#include "driverlib/pin_map.h"
#include "inc/tm4c123gh6pm.h"
#define TARGET_IS_BLIZZARD_RB1
#include "driverlib/rom.h"
#include "driverlib/sysctl.h"
#include "sensorlib/hw_isl29023.h"
#include "sensorlib/i2cm_drv.h"
#include "sensorlib/isl29023.h"
#include "driverlib/uart.h"

//functions and variables for setting up the lora network
int sendATCommand(char* ATCommand, char* expected_answer);
void loraConfigure(void);
uint8_t cond;
char luxResult[20] = "";

void stringToHex(char *luxResult);

char packet[25]="radio tx ";
char buffer[50]="";
void concatenate();


float fAmbient;
float lux;

uint32_t ui32ADC0Value[4];
uint32_t ui32ADC3Value[4];
volatile uint32_t ui32TempAvg;
volatile uint32_t ui32TempValueC;

#define DEBUG
#define ISL29023_I2C_ADDRESS 0x44 // ISL29023 I2C address
tI2CMInstance g_sI2CInst; // I2C master driver structure
tISL29023 g_sISL29023Inst; // ISL29023 sensor driver structure

volatile unsigned long g_vui8DataFlag; // Data ready flag
volatile unsigned long g_vui8ErrorFlag; // Error flag

//*************************************************************************
void ISL29023AppCallback(void *pvCallbackData, uint_fast8_t ui8Status)
{
	if(ui8Status == I2CM_STATUS_SUCCESS)
	{
		g_vui8DataFlag = 1;
	}
	g_vui8ErrorFlag = ui8Status;
}

void ISL29023I2CIntHandler(void)
{
	I2CMIntHandler(&g_sI2CInst);
}

void ISL29023AppErrorHandler(char *pcFilename, uint_fast32_t ui32Line)
{
	while(1)
	{
	}
}

void ISL29023AppI2CWait(char *pcFilename, uint_fast32_t ui32Line)
{
	while((g_vui8DataFlag == 0) && (g_vui8ErrorFlag == 0));

	if(g_vui8ErrorFlag)
	{
		ISL29023AppErrorHandler(pcFilename, ui32Line);
	}
	g_vui8DataFlag = 0;
}

int main(void)
{

	SysCtlClockSet(SYSCTL_SYSDIV_5|SYSCTL_USE_PLL|SYSCTL_XTAL_16MHZ|SYSCTL_OSC_MAIN);

	//ADC CONFIGURATION i.e. CPU TEMP
	SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0); // ENABLE ADC0 MODULE
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE); // ENABLE GPIO for ADC0
	GPIOPinTypeADC(GPIO_PORTE_BASE,GPIO_PIN_3|GPIO_PIN_2);// ENABLE A0 AND A1 OF ADC0 MODULE
	ADCSequenceConfigure(ADC0_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);
	ADCSequenceStepConfigure(ADC0_BASE, 2, 0, ADC_CTL_TS | ADC_CTL_IE |
			ADC_CTL_END);
	ADCSequenceStepConfigure(ADC0_BASE, 3, 0, ADC_CTL_CH1 | ADC_CTL_IE |
			ADC_CTL_END);


	ADCSequenceEnable(ADC0_BASE, 3);
	ADCSequenceEnable(ADC0_BASE, 2);
	//UART 0
	SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
	GPIOPinConfigure(GPIO_PA0_U0RX);
	GPIOPinConfigure(GPIO_PA1_U0TX);
	GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
	UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), 57600,
			(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_TWO | UART_CONFIG_PAR_NONE));

	//UART 1
	SysCtlPeripheralEnable(SYSCTL_PERIPH_UART1);
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
	GPIOPinConfigure(GPIO_PB0_U1RX);
	GPIOPinConfigure(GPIO_PB1_U1TX);
	GPIOPinTypeUART(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);
	UARTConfigSetExpClk(UART1_BASE, SysCtlClockGet(), 57600,
			(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE));
	//loraConfigure();


	//I2C CONFIGURATION
	SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C3);
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);
	GPIOPinConfigure(GPIO_PD0_I2C3SCL);
	GPIOPinConfigure(GPIO_PD1_I2C3SDA);
	GPIOPinTypeI2CSCL(GPIO_PORTD_BASE, GPIO_PIN_0);
	GPIOPinTypeI2C(GPIO_PORTD_BASE, GPIO_PIN_1);

	I2CMInit(&g_sI2CInst, I2C3_BASE, INT_I2C3, 0xFF, 0xFF, SysCtlClockGet());
	SysCtlDelay(SysCtlClockGet() / 3);

	//INITIALISING SENSORS
	ISL29023Init(&g_sISL29023Inst, &g_sI2CInst, ISL29023_I2C_ADDRESS,ISL29023AppCallback, &g_sISL29023Inst);
	ISL29023AppI2CWait(__FILE__, __LINE__);
	ISL29023ReadModifyWrite(&g_sISL29023Inst, ISL29023_O_CMD_I, ISL29023_CMD_I_OP_MODE_M,
			ISL29023_CMD_I_OP_MODE_ALS_CONT,
			ISL29023AppCallback, &g_sISL29023Inst);
	ISL29023AppI2CWait(__FILE__, __LINE__);

	while(1)
	{
		ISL29023DataRead(&g_sISL29023Inst, ISL29023AppCallback, &g_sISL29023Inst);
		ISL29023AppI2CWait(__FILE__, __LINE__);
		ISL29023DataLightVisibleGetFloat(&g_sISL29023Inst, &fAmbient);

		//calculating the CPU temperature
		// CLEAR INTERRUPT FLAG FOR ADC0, SEQUENCER 1
		ADCIntClear(ADC0_BASE, 1);
		// TRIGGER IS GIVEN FOR ADC 0 MODULE, SEQUENCER 1
		ADCProcessorTrigger(ADC0_BASE, 1);
		// STORE THE CONVERTED VALUE FOR ALL DIFFERENT SAMPLING IN ARRAY
		//ui32ADC0Value
		ADCSequenceDataGet(ADC0_BASE, 2, ui32ADC0Value);
		ui32TempAvg = (ui32ADC0Value[0] + ui32ADC0Value[1] + ui32ADC0Value[2] + ui32ADC0Value[3] + 2)/4;
		ui32TempValueC = (1475 - ((2475 * ui32TempAvg)) / 4096)/10;

		//calculating decibal values

		ADCSequenceDataGet(ADC0_BASE,3,ui32ADC3Value);

		//lux=172.607;
		//transmiting data via LoRa
		sprintf(luxResult, "%g",lux);
		stringToHex(luxResult);
		concatenate();//creating a packet to be transfered
		sendATCommand(packet,"OK\0");
		SysCtlDelay(20000000);//500ms delay
		sendATCommand("sys reset\r\n\0","OK\0");
		lux=fAmbient;
	}
}
int sendATCommand(char* ATCommand, char* expected_answer)
{
	uint8_t answer=0;
	while(*ATCommand!='\0')
	{
		UARTCharPut(UART1_BASE, *ATCommand);
		ATCommand++;
	}
	SysCtlDelay(4000000);//100 ms delay
	while(UARTCharsAvail(UART1_BASE))
	{
		UARTCharPut(UART0_BASE, UARTCharGet(UART1_BASE));
		answer=1;
	}
	return answer;
}
void loraConfigure(void)
{
	cond=sendATCommand("radio set mod lora\r\n\0","OK\0");
	SysCtlDelay(400000);//10ms delay
	cond=sendATCommand("radio get mod\r\n\0","lora\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio set pwr 15\r\n\0","OK\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio get pwr\r\n\0","15\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio set freq 868100000\r\n\0","OK\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio get freq\r\n\0","868100000\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio set sf sf12\r\n\0","OK\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio get sf\r\n\0","sf12\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio set cr 4/5\r\n\0","OK\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio get cr\r\n\0","4/5\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio set bw 125\r\n\0","OK\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio get bw\r\n\0","125\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio set crc on\r\n\0","OK\0");
	SysCtlDelay(400000);
	cond=sendATCommand("radio get crc\r\n\0","on\0");
	SysCtlDelay(400000);
}
void stringToHex(char *luxResult)
{

	char *pbuffer = buffer;
	int i;
	int len=strlen( luxResult );
	for(i=0;i<len;i++)
	{
		sprintf(pbuffer, "%x", luxResult[i]);
		pbuffer +=2;
	}
}
void concatenate()
{
	int count=9,i=0;
	while(buffer[i]!='\0')
	{
		packet[count]=buffer[i];
		count++;
		i++;
	}
	packet[count++]='\r';
	packet[count++]='\n';
}