adc中断一进去就再也出不来了，求大侠告诉我为什么

adc中断一进去就再也出不来了，求大侠告诉我为什么

#include"msp430f169.h"
//#include "keypad.h"
#include "1602(zhp)LT.h"
//#include"舵机.h"
#include"BoardConfig.h"
/********************************************
软件延时
********************************************/
//typedef unsigned int uint;
//typedef unsigned char uchar;
#define CPU_F ((double)8000000)
#define DELAY_US(x) __delay_cycles((long)(CPU_F*(double)x/1000000.0))
#define DELAY_MS(x) __delay_cycles((long)(CPU_F*(double)x/1000.0))
#define delay_us(x) __delay_cycles((long)(CPU_F*(double)x/1000000.0))
#define delay_ms(x) __delay_cycles((long)(CPU_F*(double)x/1000.0))
#define num 20
unsigned char wan,qian,bai,shi,ge;
unsigned int results[num]={0};
unsigned char t=0;
unsigned int ave=0;
unsigned int filter[2];
void transform(unsigned int dat)
{
  wan=dat/10000+0x30;
  qian=dat%10000/1000+0x30;
  bai=dat%1000/100+0x30;
  shi=dat%100/10+0x30;
  ge=dat%10+0x30;
}
void main()
{
  WDTCTL = WDTPW+WDTHOLD;  //关闭看门狗
  BCSCTL1 &= ~XT2OFF;
  while(IFG1&OFIFG)
  {
    IFG1&= ~OFIFG;
    DELAY_US(50);
  }
  BCSCTL2 |= SELM_2+SELS+DIVS_3; //MCLK 8M,SMCLK 1M
  lcd_init1602 ();
  //keypad_init();
  //write1char1602(0,0,i/10+0x30);
  //BoardConfig(0xb8);//11111000
  //_EINT();

  WDTCTL=WDTPW+WDTHOLD;
  P6SEL|=BIT1;
  ADC12CTL0=ADC12ON+SHT0_8+SHT1_8+MSC;
  ADC12CTL1=SHP+CONSEQ_2+CSTARTADD_1;
  ADC12MCTL1=INCH_1;
  ADC12IE=BIT1;
  ADC12CTL0|=ENC;
  _EINT();
  ADC12CTL0|=ADC12SC;
  while(2);
}
#pragma vector=ADC_VECTOR
__interrupt void ADC12ISR()
{
  ADC12IFG=0X00;
  t++;
  filter[0]=ADC12MEM0;
  if(filter[0]-filter[1]>5)
    ave=ave+filter[1];
  else
    ave=ave+filter[0];
  if(t==11)
  {
    t=0;
    ave=(unsigned int)(ave/11);
    transform(ave);
    write1char1602(0,0,wan);
    write1char1602(1,0,qian);
    write1char1602(2,0,bai);
    write1char1602(3,0,shi);
    write1char1602(4,0,ge);
    ave=0;
  }
  filter[1]=filter[0];

}

真的被困扰了很久很久啊，总是解决不了，都快疯了。。