K60 超声波测距程序。在KEIL上写的，，大家看看有什么问题

zhangxin1992109 · 发表于 2014-3-18 19:46:00

unsigned int L_CSB()
{
int16_t L_distance=0;
unsigned int L_Echo = 0;

L_Echo=(PTD->PDIR & 0x0000e000);
L_Echo=L_Echo>>12;
   L_Trig_On; //Trig脚拉高
     NVIC_EnableIRQ(PIT1_IRQn);//开启定时器
   while(!(count>=4));//等待20us
   NVIC_DisableIRQ(PIT1_IRQn);
   count=0; //计数清零
   L_Trig_Off; //Trig脚拉低
   // PTA15_OUT=0;//指示灯亮
   while(L_Echo||0x00);//等待Echo脚拉高
   NVIC_EnableIRQ(PIT1_IRQn);//开启定时器
   while(!((L_Echo||0x00) || count>=4500));    //等待Echo脚拉低或计时溢出
   L_distance = count*17/20;  //计算距离，单位mm

   NVIC_DisableIRQ(PIT1_IRQn);//关闭定时器
   count=0;
   return L_distance;

}