MSP430F5528: MSP430G2ET + TRF7970A ser.write() how to clear the transmit and receive buffers and restart in main loop

import serial.tools.list_ports
import time

ns_val = time.time_ns()

serPort = ""
int1 = 0
str1 = ""
str2 = ""

ports = list(serial.tools.list_ports.comports())
for p in ports:
    print(p)  # This causes each port's information to be printed out.
    # To search this p data, use p[1].

    while int1 < 20:  # Loop checks "COM0" to "COM8" for Msp Port Info.

        if "UART1" in p[1]:  # Looks for "UART1" in P[1].
            str2 = str(int1)  # Converts an Integer to a String, allowing:
            str1 = "COM" + str2  # add the strings together.

        if "UART1" in p[1] and str1 in p[1]:  # Looks for "Msp" and "COM#"
            print("Found MSP430 on %s" % (str1))
            int1 = 20  # Causes loop to end.

        if int1 == 19:
            print("MSP not found!")

        int1 = int1 + 1
    int1 = 0

# Set Port
ser = serial.Serial(str1, 9600, bytesize=serial.EIGHTBITS)  # Put in your speed and timeout value.
ser.close()

ns_ports = time.time_ns()

# get UID from UART
data1 = ""
ser.close()
ser.open()
ser.write('0'.encode())
buffer = ser.readline()
UID = ser.readline().decode('UTF-8')
UID = UID.replace("\n", "")  # replace \n so we don't have a paragraph
print("NFC UID: ",UID)
ser.close()

ns_uid = time.time_ns()

time_needed_for_port_init = (((ns_ports - ns_val)/1000000)/1000)
time_needed_for_read_uid = (((ns_uid - ns_ports)/1000000)/1000)

print("Time port init: ",time_needed_for_port_init)
print("Time read uid: ",time_needed_for_read_uid)

#include "nfc_app.h"
#include "trf79xxa.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "clock.h"


void Send_UID(void)
{
    uint8_t ui8LoopCount = 0;
    for (ui8LoopCount = 0; ui8LoopCount < 8; ui8LoopCount++) //8 Byte UID. Po Schleifendurchlauf 1 Byte an Host gesendet
    {
        UART_putByte(g_pui8Iso15693UId[7-ui8LoopCount]);        // Send UID to host
    }
    UART_putNewLine(); //nachdem die UID gesendet wurde wird eine leere Zeile gesendet (zur Übersichtlichkeit)
}


void main(void)
{

    uint8_t ui8VLOCalibCount = 0;
    //  TODO: Remove LED2 Jumper on G2 LaunchPad if using it, otherwise SPI will not work.

            // Stop the Watchdog timer,

    WDTCTL = WDTPW + WDTHOLD;
    P1DIR |= BIT0;
    P1OUT &= ~BIT0;
    // Select DCO to be 8 MHz
    MCU_initClock();
    MCU_delayMillisecond(10);

    // Calibrate VLO
    MCU_calculateVLOFreq();

    // Set the SPI SS high
    SLAVE_SELECT_PORT_SET;
    SLAVE_SELECT_HIGH;

    // Four millisecond delay between bringing SS high and then EN high per TRF7970A Datasheet
    MCU_delayMillisecond(4);

    // Set TRF Enable Pin high
    TRF_ENABLE_SET;
    TRF_ENABLE;

    // Wait until TRF system clock started
    MCU_delayMillisecond(5);

    // Set up TRF initial settings
    TRF79xxA_initialSettings();
    TRF79xxA_setTrfPowerSetting(TRF79xxA_5V_FULL_POWER);

#ifdef ENABLE_HOST
    // Set up UART
    UART_setup();
    IE2 |= UCA0RXIE;
    _BIS_SR(GIE);
#endif

    // Initialize all enabled technology layers
    NFC_init();


    // Enable global interrupts
    __bis_SR_register(GIE);
    __enable_interrupt();

    // Enable IRQ Pin
    IRQ_ON;

#ifdef ENABLE_HOST
    //    UART_putIntroReaderMsg();
#endif
    TRF79xxA_setupInitiator(0x02);

    // The VCD should wait at least 1 ms after it activated the
    // powering field before sending the first request, to
    while(1)
    {
        UART_putNewLine();
        Change_Protect_Status = true;
        New_Password = true;
        Write_Data = true;
        Reset_Data = true;
        askdiff = true;
        uint8_t  ui8LoopCount = 0;       // ensure that the VICCs are ready to receive it. (ISO15693-3)
        MCU_delayMillisecond(100);
        ISO15693_resetTagCount();
        ISO15693_SingleInventory();
        Send_UID();
        MCU_delayMillisecond(20);
        while(UART_Not_Recieved)
        {

        }
        UART_Not_Recieved = true;


        if(RX== '1') //Read all datablocks
        {
            UART_putNewLine();
            My_sendReadMultipleBlocks(0x22,  0, 42);
            MCU_delayMillisecond(80);
            My_sendReadMultipleBlocks(0x22, 42, 11);
        }
	for (ui8LoopCount = 0; ui8LoopCount < 8; ui8LoopCount++)
        {
            g_pui8Iso15693UId[ui8LoopCount] = 0;        // Send UID to host
        }
        // VLO drifts with temperature and over time, so it must be periodically recalibrated
        // Calibrate the VLO every 25 passes of the NFC polling routine
        ui8VLOCalibCount++;
        if (ui8VLOCalibCount == 25)
        {
            // Calibrate VLO
            MCU_calculateVLOFreq();
            // Reset Calibration Counter
            ui8VLOCalibCount = 0;
        }
    }
}