EVM430-FR6047: eUSCI_A1无法收发数据

将例程msp430fr60x7_euscia0_uart_02.c（此例程是eUSCI_A0）烧录开发板，可以实现数据回显。但我将程序改成eUSCI_A1,发现烧录开发板后无法进入中断，程序如下：

#include <msp430.h>

int main(void)
{
    WDTCTL = WDTPW | WDTHOLD;               // Stop Watchdog

    // Configure GPIO
    P1SEL0 &= ~(BIT2 | BIT3);
    P1SEL1 |= BIT2 | BIT3;                  // USCI_A1 UART operation
    PJSEL0 |= BIT4 | BIT5;                  // For XT1

    // Disable the GPIO power-on default high-impedance mode to activate
    // previously configured port settings
    PM5CTL0 &= ~LOCKLPM5;

    // XT1 Setup
    CSCTL0_H = CSKEY_H;                     // Unlock CS registers
    CSCTL2 = SELA__LFXTCLK | SELS__DCOCLK | SELM__DCOCLK;
    CSCTL3 = DIVA__1 | DIVS__1 | DIVM__1;   // Set all dividers
    CSCTL4 &= ~LFXTOFF;
    do
    {
        CSCTL5 &= ~LFXTOFFG;                // Clear XT1 fault flag
        SFRIFG1 &= ~OFIFG;
    } while (SFRIFG1 & OFIFG);              // Test oscillator fault flag
    CSCTL0_H = 0;                           // Lock CS registers

    // Configure USCI_A1 for UART mode
    UCA1CTLW0 = UCSWRST;                    // Put eUSCI in reset
    UCA1CTLW0 |= UCSSEL__ACLK;              // CLK = ACLK
    UCA1BRW = 3;                            // 9600 baud
    UCA1MCTLW |= 0x5300;                    // 32768/9600 - INT(32768/9600)=0.41
                                            // UCBRSx value = 0x53 (See UG)
    UCA1CTLW0 &= ~UCSWRST;                  // Initialize eUSCI
    UCA1IE |= UCRXIE;                       // Enable USCI_A1 RX interrupt

    __bis_SR_register(LPM3_bits | GIE);     // Enter LPM3, interrupts enabled
    __no_operation();                       // For debugger


}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=EUSCI_A1_VECTOR
__interrupt void USCI_A1_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(EUSCI_A1_VECTOR))) USCI_A1_ISR (void)
#else
#error Compiler not supported!
#endif
{
    switch(__even_in_range(UCA1IV, USCI_UART_UCTXCPTIFG))
    {
        case USCI_NONE: break;
        case USCI_UART_UCRXIFG:
            while(!(UCA1IFG&UCTXIFG));
            UCA1TXBUF = UCA1RXBUF;
            __no_operation();
            break;
        case USCI_UART_UCTXIFG: break;
        case USCI_UART_UCSTTIFG: break;
        case USCI_UART_UCTXCPTIFG: break;
        default: break;
    }
}