TM4C123GH6PM: TM4C123xx UART Stdio

I am currently working on UART and Timers. UART part is running fine, but when I introduce Timer in the same code UART stops working. What might be the problem?

/* U0Rx receive connected to PA0
U0Tx transmit connected to PA1 */

#include <stdio.h>
#include <stdint.h>
#include "tm4c123gh6pm.h"

void UART_Init(void);
void PortF_Init(void);
void PortE_Init(void);
void Timer_Init(void);


int main(void)
{
volatile unsigned long delay_timer=0;

char c;
PortF_Init();
UART_Init();
PortE_Init();

/* This is timer initialiazation section. Uncommenting any statement stops the working of UART*/

// SYSCTL_RCGC1_R |= 0x00010000; //enable clock to Timer Block 0 (pg 460)
// delay_timer = SYSCTL_RCGC1_R; // Delay for 3-4 clock cycles
// TIMER0_CTL_R = 0x00; // disable Timer0 before initialization (pg 737 )
// TIMER0_CFG_R = 0x00; // 32-bit option (pg 727 )
// TIMER0_TAMR_R = 0x01; // One shot mode and down-counter (pg 729 )
// TIMER0_ICR_R = 0x01; // clear the TimerA timeout flag(pg 754 )

/* UART Section*/

while(1){

while( (UART0_FR_R & 0x00000010) != 0)
{
}

c=UART0_DR_R;
if(c==10)
{
GPIO_PORTF_DATA_R = 0x08;
UART0_DR_R=c;

UART0_FR_R=0x00000080;
while((UART0_FR_R&0x00000008)==1)
{
}

}

if(c==01)
{
GPIO_PORTF_DATA_R = 0x04;

UART0_DR_R=c;
UART0_FR_R=0x00000080;
while((UART0_FR_R&0x00000008)==1)
{
}

}

if(c==00)
{
GPIO_PORTF_DATA_R = 0x00;
UART0_DR_R=c;
UART0_FR_R=0x00000080;
while((UART0_FR_R&0x00000008)==1)
{
}
}
}
}

/* UART_Init*/

void UART_Init(void)
{
SYSCTL_RCGCUART_R |= 0x01; /* activate UART0 */
SYSCTL_RCGC2_R |= 0x01; /* activate port A */

UART0_CTL_R = 0x00000000; /* disable UART */
UART0_IBRD_R = 104; /* IBRD = int(16,000,000 / (16 * 9600)) = int(104.1667) */
UART0_FBRD_R = 11; /* FBRD = round(0.1667 * 64 ) = 11 */

UART0_LCRH_R = 0x70; /* 8 bit word length (no parity bits, one stop bit, FIFOs) */
UART0_CTL_R = 0x0301; /* enable UART, RXE, TXE, LBE */
GPIO_PORTA_AFSEL_R |= 0x03; /* enable alt funct on PA1-0 */
GPIO_PORTA_DEN_R |= 0x03; /* enable digital I/O on PA1-0 */
GPIO_PORTA_PCTL_R = ((GPIO_PORTA_PCTL_R & 0xFFFFFF00)+0x00000011); /* configure PA1-0 as UART */
GPIO_PORTA_AMSEL_R &= ~0x03; /* disable analog functionality on PA */
}

void PortF_Init(void){ volatile unsigned long delay;
SYSCTL_RCGC2_R |= 0x00000020; // 1) F clock
delay = SYSCTL_RCGC2_R; // delay
GPIO_PORTF_LOCK_R = 0x4C4F434B; // 2) unlock PortF PF0
GPIO_PORTF_CR_R = 0x0E; // allow changes to PF4-0
GPIO_PORTF_AMSEL_R = 0x00; // 3) disable analog function
GPIO_PORTF_PCTL_R = 0x00000000; // 4) GPIO clear bit PCTL
GPIO_PORTF_DIR_R = 0x0E; // 5) PF4,PF0 input, PF3,PF2,PF1 output
GPIO_PORTF_AFSEL_R = 0x00; // 6) no alternate function
GPIO_PORTF_DEN_R = 0x0E; // 7) enable digital pins PF4-PF0
}

void PortE_Init(void){ volatile unsigned long delay;
SYSCTL_RCGC2_R |= 0x00000010; // 1) E clock
delay = SYSCTL_RCGC2_R; // delay
GPIO_PORTE_LOCK_R = 0x4C4F434B; // 2) unlock
GPIO_PORTE_CR_R = 0x06; // allow changes to PE2-1
GPIO_PORTE_AMSEL_R = 0x00; // 3) disable analog function
GPIO_PORTE_PCTL_R = 0x00000000; // 4) GPIO clear bit PCTL
GPIO_PORTE_DIR_R = 0x06; // 5) PE2-1output
GPIO_PORTE_AFSEL_R = 0x00; // 6) no alternate function
GPIO_PORTE_PUR_R = 0x06; // enable pullup resistors
GPIO_PORTE_DEN_R = 0x06; // 7) enable digital pins
}