[参考译文] MSP430FR2433：如何提高 UART 输出可靠性？

WDTCTL = WDTPW | WDTCNTCL | WDTSSEL_1 | WDTIS_3; // Start watchdog timer
PM5CTL0 &= ~LOCKLPM5;                    // Disable the GPIO power-on default high-impedance mode to activate previously configured port settings
// Setup clock
__bis_SR_register(SCG0);                 // disable FLL
CSCTL3 |= SELREF__REFOCLK;               // Set REFO as FLL reference source
CSCTL0 = 0;                              // clear DCO and MOD registers
CSCTL1 &= ~(DCORSEL_7);                  // Clear DCO frequency select bits first
CSCTL1 |= DCORSEL_3;                     // Set DCO = 8MHz
CSCTL2 = FLLD_0 + 243;                   // DCODIV = 8MHz
__delay_cycles(3);
__bic_SR_register(SCG0);                 // enable FLL
while(CSCTL7 & (FLLUNLOCK0 | FLLUNLOCK1)); // Poll until FLL is locked
CSCTL4 = SELMS__DCOCLKDIV | SELA__REFOCLK; // set default REFO(~32768Hz) as ACLK source, ACLK = 32768Hz, default DCODIV as MCLK and SMCLK source

// Code to initialize UART
UCA1BR0 = 52; // 8000000/16/9600
UCA1BR1 = 0x00;
UCA1MCTLW = 0x4900 | UCOS16 | UCBRF_1;
UCA1CTLW0 &= ~UCSWRST; // Initialize eUSCI
UCA1IE |= UCRXIE;     // Enable USCI_A0 RX interrupt

// Code to enter into sleep
__bis_SR_register(LPM3_bits | GIE); // Enter LPM3

// Code to wake up from GPIO interrupt
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector = PORT2_VECTOR
__interrupt void Port_2(void)
#elif defined(__GNUC__)
void __attribute__((interrupt(PORT1_VECTOR))) Port_2(void)
#else
#error Compiler not supported!
#endif
{
    if (P2IFG & BIT7)
    {
        P2IFG &= ~BIT7;
        __low_power_mode_off_on_exit();
    }
}