Using timer for delay

#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include "inc/hw_memmap.h"
#include "driverlib/interrupt.h"
#include "driverlib/gpio.h"
#include "driverlib/sysctl.h"
#include "inc/hw_types.h"
#include "inc/hw_ints.h"
#include "inc/hw_gpio.h"
#include "driverlib/timer.h"

#define SW1			GPIO_PIN_4
#define SW2 		GPIO_PIN_0

#define LED_RED		GPIO_PIN_1
#define LED_GREEN	GPIO_PIN_2
#define LED_BLUE	GPIO_PIN_3


uint32_t readStatus,ui32Period,tinh;
uint32_t val=0;
int tick;

void INIT_LED()
{
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
	GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3);
	GPIOPinWrite(GPIO_PORTF_BASE,  LED_RED|LED_GREEN|LED_BLUE, 0);
}

void config_timer()
{
		SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
		TimerConfigure(TIMER0_BASE, TIMER_CFG_A_PERIODIC_UP);
		ui32Period = (SysCtlClockGet()/8);//5s
		TimerLoadSet(TIMER0_BASE, TIMER_A, ui32Period);//5s
		TimerEnable(TIMER0_BASE, TIMER_A);
}
uint32_t flg=0;
int main(void) {
	SysCtlClockSet(SYSCTL_SYSDIV_2_5| SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);
	INIT_LED();
	config_timer();
	ui32Period= ui32Period/2;
    valLED = LED_RED;
    while(1)
    {
    	val=TimerValueGet(TIMER0_BASE,TIMER_A);
    	if(TimerValueGet(TIMER0_BASE,TIMER_A) < ui32Period)
    	{
    		flg =1;
    	}
    	else
    		flg=0;
    	if(!flg)
    		GPIOPinWrite(GPIO_PORTF_BASE,  LED_RED, valLED);
    	else
    		GPIOPinWrite(GPIO_PORTF_BASE,  LED_RED, 0);
    }
}

I'd like to create a delay timer. period is 5 second. Ton = 2.5 sec, Duty = 50%.
My code as above, something wrong, I can not create a program as my desire. Ton so short.

Please help to indicate to where is my errors.

Thanks in advanced!