CCS/TM4C123GH6PM: Issue on TIMERS frequency

Part Number:TM4C123GH6PM

Tool/software: Code Composer Studio

Hi

I need to generate two signals for driving a device, one at 25 Hz and another one to 1.4MHz. I have been testing with the code below but I can only achieve 645 kHz even setting the Load to 1.4Mhz, is there something am I doing wrong?
I can also notice that in some frequencies the duty cycle changes with no reason since I left it on 50%. I am trying to figure out what is happening on the datasheet and the TIVA peripherals library but since I am beginner with the Tiva C any help is appreciated.

Thanks in advance

Isra

#include <stdint.h>
#include <stdbool.h>
#include "inc/tm4c123gh6pm.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/sysctl.h"
#include "driverlib/interrupt.h"
#include "driverlib/gpio.h"
#include "driverlib/timer.h"


int main(void)
{
    uint32_t ui32Period;

    //SysCtlClockSet(SYSCTL_SYSDIV_5|SYSCTL_USE_PLL|SYSCTL_XTAL_16MHZ|SYSCTL_OSC_MAIN);
    SysCtlClockSet(SYSCTL_SYSDIV_2_5 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
    GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
    TimerConfigure(TIMER0_BASE, TIMER_CFG_PERIODIC);
    ui32Period = (SysCtlClockGet()/25) / 2 ;
    TimerLoadSet(TIMER0_BASE, TIMER_A, ui32Period -1);
    IntEnable(INT_TIMER0A);
    TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT);
    //IntMasterEnable();
    TimerEnable(TIMER0_BASE, TIMER_A);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER2);
    TimerConfigure(TIMER2_BASE, TIMER_CFG_PERIODIC);
    ui32Period = (SysCtlClockGet()/10) / 2;
    TimerLoadSet(TIMER2_BASE, TIMER_A, ui32Period -1);
    IntEnable(INT_TIMER2A);
    TimerIntEnable(TIMER2_BASE, TIMER_TIMA_TIMEOUT);
    //IntMasterEnable();
    TimerEnable(TIMER2_BASE, TIMER_A);


    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER1);
    TimerConfigure(TIMER1_BASE, TIMER_CFG_PERIODIC);
    ui32Period = (SysCtlClockGet()/1400000) /2 ;
    TimerLoadSet(TIMER1_BASE, TIMER_A, ui32Period -1);
    IntEnable(INT_TIMER1A);
    TimerIntEnable(TIMER1_BASE, TIMER_TIMA_TIMEOUT);
    IntMasterEnable();
    TimerEnable(TIMER1_BASE, TIMER_A);


    while(1)
    {
    }
}

void Timer0IntHandler(void)
{
    // Clear the timer interrupt
    TimerIntClear(TIMER0_BASE, TIMER_TIMA_TIMEOUT);

    // Read the current state of the GPIO pin and
    // write back the opposite state
    if(GPIOPinRead(GPIO_PORTF_BASE, GPIO_PIN_2))
    {
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3, 0);
    }
    else
    {
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, 4);
    }
}

void Timer1IntHandler(void)
{
    // Clear the timer interrupt
    TimerIntClear(TIMER1_BASE, TIMER_TIMA_TIMEOUT);

    // Read the current state of the GPIO pin and
    // write back the opposite state
    if(GPIOPinRead(GPIO_PORTF_BASE, GPIO_PIN_1))
    {
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, 0);
    }
    else
    {
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, 2);
    }
}

void Timer2IntHandler(void)
{
    // Clear the timer interrupt
    TimerIntClear(TIMER2_BASE, TIMER_TIMA_TIMEOUT);

    // Read the current state of the GPIO pin and
    // write back the opposite state
    if(GPIOPinRead(GPIO_PORTF_BASE, GPIO_PIN_3))
    {
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_3, 0);
    }
    else
    {
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_3, 8);
    }
}