6733 xt1晶振问题

void setup_FLL(void)
{//启动晶振和时钟；
  WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer

  UCSCTL6 &= ~(XT1OFF);                  // XT1 On

  do
  {
    UCSCTL7 &= ~XT1LFOFFG;             // Clear XT1 fault flags
    for (int i = 30000; i; i--);
  } while (UCSCTL7 & XT1LFOFFG);         // Test XT1 fault flag
  
    
    UCSCTL3 = SELREF__XT1CLK;             // Set DCO FLL reference
    
    
    UCSCTL4 = SELS__DCOCLKDIV + SELM__DCOCLK + SELA__XT1CLK;

    __delay_cycles(781250);  
    
    while (SFRIFG1&OFIFG)                   // Test oscillator fault flag
  {                       // Clear fault flags
    UCSCTL7 &= ~(XT1LFOFFG + DCOFFG); // Clear XT2,XT1,DCO fault flags
    SFRIFG1 &= ~OFIFG;                          // Clear fault flags
    for (int i = 30000; i; i--);
  }

}