Tx to Pc with switch interrupt

#include "msp.h"
#define SYSTICK_STCSR (*((volatile unsigned long *)0xE000E010))
#define SYSTICK_STRVR (*((volatile unsigned long *)0xE000E014))
#define SYSTICK_STCVR (*((volatile unsigned long *)0xE000E018))

void SysTick_Init(void);
void SysTick_wait(uint32_t delay);
void SysTick_wait1ms(uint32_t delay);
void Port_Init(void);
void UART0_init(void);

int main(void) {
    SysTick_Init();
    Port_Init();
    UART0_init();

    while (1) {
        P2OUT |= 0x01;
        SysTick_wait1ms(200);
        P2OUT &= ~0x01;
        SysTick_wait1ms(200);
    }
}

void SysTick_Init(void) {
    SYSTICK_STCSR = 0;
    SYSTICK_STRVR = 0x00FFFFFF;
    SYSTICK_STCVR = 0;
    SYSTICK_STCSR = 0x00000005;
}

void SysTick_wait(uint32_t delay) {
    SYSTICK_STRVR = delay - 1;
    SYSTICK_STCVR = 0;
    while ((SYSTICK_STCSR & 0x00010000) == 0) {
    }
}

void SysTick_wait1ms(uint32_t delay) {
    uint32_t i;
    for (i = 0; i < delay; i++) {
        SysTick_wait(3000);
    }
}

void Port_Init(void) {

    P5SEL1 = 0x00;
    P5SEL0 = 0x00;
    P5DIR = 0x00;
    P5REN = 0x01;
    P5OUT = 0x01;
    P5IES = 0x01;
    P5IFG = 0;
    P5IE = 0x01;

    P6SEL1 = 0x00;
    P6SEL0 = 0x00;
    P6DIR = 0x00;
    P6REN = 0x01;
    P6OUT = 0x01;
    P6IES = 0x01;
    P6IFG = 0;
    P6IE = 0x01;

    P2SEL1 = 0x00;
    P2SEL0 = 0x00;
    P2DIR = 0x07;
    P2OUT = 0x00;

    NVIC_SetPriority(PORT5_IRQn,2);
    NVIC_SetPriority(PORT6_IRQn,0);
    NVIC_EnableIRQ(PORT5_IRQn);
    NVIC_EnableIRQ(PORT6_IRQn);
    __enable_irq();
}

void PORT5_IRQHandler(void){
    char buff[10] = "SW1 Active";
    for (int i=0;i<10;i++){
        while (!(EUSCI_A0->IFG & 0x02));
        EUSCI_A0->TXBUF = buff[i];
    }
    while (!(EUSCI_A0->IFG & 0x02));
    EUSCI_A0->TXBUF = 0x0a;
    for (int i=0; i<3; i++){
        P2OUT = 0x04;
        SysTick_wait1ms(500);
        P2OUT &= ~0x04;
        SysTick_wait1ms(500);
    }
    P5IFG &= 0x00;
}

void PORT6_IRQHandler(void){
    char buff[10] = "SW2 Active";
    for (int i=0;i<10;i++){
        while (!(EUSCI_A0->IFG & 0x02));
        EUSCI_A0->TXBUF = buff[i];
    }
    while (!(EUSCI_A0->IFG & 0x02));
    EUSCI_A0->TXBUF = 0x0a;
    for (int i=0; i<3; i++){
        P2OUT = 0x02;
        SysTick_wait1ms(500);
        P2OUT &= ~0x02;
        SysTick_wait1ms(500);
    }
    P6IFG &= 0x00;
}

void UART0_init(void){
    EUSCI_A0->CTLW0 |= 1;
    EUSCI_A0->MCTLW = 0;
    EUSCI_A0->CTLW0 = 0x0081;
    EUSCI_A0->BRW = 312;
    P1->SEL0 |= 0x0C;
    P1->SEL1 &= ~0x0C;
    EUSCI_A0->CTLW0 &= ~0x0001;
}