MSP432P401R: uart halt

hi,thanks for your reply, i wonder reset means set 1 or set 0,UCTXIFG default is 1,that means reset is set 1?

/*
 * -------------------------------------------
 *    MSP432 DriverLib - v4_00_00_11 
 * -------------------------------------------
 *
 * --COPYRIGHT--,BSD,BSD
 * Copyright (c) 2017, Texas Instruments Incorporated
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * *  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * *  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * *  Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * --/COPYRIGHT--*/
/******************************************************************************
 * MSP432 UART - PC Echo with 12MHz BRCLK
 *
 * Description: This demo echoes back characters received via a PC serial port.
 * SMCLK/DCO is used as a clock source and the device is put in LPM0
 * The auto-clock enable feature is used by the eUSCI and SMCLK is turned off
 * when the UART is idle and turned on when a receive edge is detected.
 * Note that level shifter hardware is needed to shift between RS232 and MSP
 * voltage levels.
 *
 *               MSP432P401
 *             -----------------
 *            |                 |
 *            |                 |
 *            |                 |
 *       RST -|     P1.3/UCA0TXD|----> PC (echo)
 *            |                 |
 *            |                 |
 *            |     P1.2/UCA0RXD|<---- PC
 *            |                 |
 *
 * Author: Timothy Logan
*******************************************************************************/
/* DriverLib Includes */
#include <ti/devices/msp432p4xx/driverlib/driverlib.h>

/* Standard Includes */
#include <stdint.h>
#include <stdio.h>
#include <stdbool.h>

/* UART Configuration Parameter. These are the configuration parameters to
 * make the eUSCI A UART module to operate with a 9600 baud rate. These
 * values were calculated using the online calculator that TI provides
 * at:
 *http://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/MSP430BaudRateConverter/index.html
 */
const eUSCI_UART_Config uartConfig =
{
        EUSCI_A_UART_CLOCKSOURCE_SMCLK,          // SMCLK Clock Source
        6,                                     // BRDIV = 78
        8,                                       // UCxBRF = 2
        32,                                       // UCxBRS = 0
        EUSCI_A_UART_NO_PARITY,                  // No Parity
        EUSCI_A_UART_LSB_FIRST,                  // LSB First
        EUSCI_A_UART_ONE_STOP_BIT,               // One stop bit
        EUSCI_A_UART_MODE,                       // UART mode
        EUSCI_A_UART_OVERSAMPLING_BAUDRATE_GENERATION  // Oversampling
};

int main(void)
{
    /* Halting WDT  */
    MAP_WDT_A_holdTimer();
// MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P1,
             //GPIO_PIN1 , GPIO_PRIMARY_MODULE_FUNCTION);
    /* Selecting P1.2 and P1.3 in UART mode */
   // MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P1,
            // GPIO_PIN2 | GPIO_PIN3, GPIO_PRIMARY_MODULE_FUNCTION);
	
MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P1,
             GPIO_PIN2 | GPIO_PIN3, GPIO_PRIMARY_MODULE_FUNCTION);

    /* Setting DCO to 12MHz */
    CS_setDCOCenteredFrequency(CS_DCO_FREQUENCY_12);

    /* Configuring UART Module */
    //MAP_UART_initModule(EUSCI_A0_BASE, &uartConfig);
MAP_UART_initModule(EUSCI_A0_BASE, &uartConfig);

    /* Enable UART module */
    //MAP_UART_enableModule(EUSCI_A0_BASE);
MAP_UART_enableModule(EUSCI_A0_BASE);

    /* Enabling interrupts */
    //MAP_UART_enableInterrupt(EUSCI_A1_BASE, EUSCI_A_UART_RECEIVE_INTERRUPT);
   //MAP_Interrupt_enableInterrupt(INT_EUSCIA1);
	 MAP_UART_enableInterrupt(EUSCI_A0_BASE, EUSCI_A_UART_RECEIVE_INTERRUPT);
    MAP_Interrupt_enableInterrupt(INT_EUSCIA0);
    MAP_Interrupt_enableSleepOnIsrExit();
   MAP_Interrupt_enableMaster();   
    
    while(1)
    {
   
			MAP_UART_transmitData(EUSCI_A0_BASE,'1');
			
			//MAP_Interrupt_enableSleepOnIsrExit();
			//MAP_PCM_gotoLPM3InterruptSafe();
			//MAP_PCM_gotoLPM0();
    }
}




/* EUSCI A0 UART ISR - Echoes data back to PC host */
void EUSCIA0_IRQHandler(void)
{
    uint32_t status = MAP_UART_getEnabledInterruptStatus(EUSCI_A0_BASE);

    MAP_UART_clearInterruptFlag(EUSCI_A0_BASE,status);
     
    if(status & EUSCI_A_UART_RECEIVE_INTERRUPT_FLAG)

    {
			MAP_UART_receiveData(EUSCI_A0_BASE);
       // MAP_UART_transmitData(EUSCI_A0_BASE, MAP_UART_receiveData(EUSCI_A0_BASE));
			 // MAP_UART_transmitData(EUSCI_A0_BASE, 'p');
			//MAP_UART_receiveData(EUSCI_A1_BASE);
			//MAP_UART_transmitData(EUSCI_A1_BASE,MAP_UART_receiveData(EUSCI_A1_BASE));
    }

}


if my pc send data to uart0 and at the same time uart0 send data to pc this program wil stuck