[LaunchPad] 时钟的初应用

#include "io430g2553.h"

void main(void)
{
   volatile unsigned int i;
   
   WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog timer

 //------------------------------------------
 //ACLK = n/a , MCLK = DCO/8 , SMLK = DCO/8 
BCSCTL1=CALBC1_16MHZ ; //Setrange
DCOCTL=CALDCO_16MHZ; //设置DCO模式
BCSCTL2|=SELM_0 + DIVM_3 + DIVS_3;

//-------------------------------------------
//ACLK = VLO , MCLK = VLO/8 , SMLK = VLO/8
/*
BCSCTL3 |= LFXT1S_2 ; //ACLK = VLO   
IFG1 &= ~OFIFG;
BCSCTL2|= SELM_3 + DIVM_3 + SELS + DIVS_3;
*/


//__bis_SR_register(SCG1+SCG0); // 关闭 DCO


  P1OUT |= 0xff; 
  P1DIR |= 0xff;                            // Set P1.0 to output direction
  
  
  P1DIR_bit.P3 = 0; 
  P1REN_bit.P3 = 1;

  for (;;)
  {
   
    if(P1IN_bit.P3)
    {
    P1OUT_bit.P6 = P1OUT_bit.P0;
    P1OUT_bit.P0 = ~P1OUT_bit.P0;
    }
    
    for(i=5000;i>0;i--);
   
  }
}

外接32kHz晶振，无法起振，不知是何情况