HAL超声波测距

extern TIM_HandleTypeDef htim7;
/*
³¬Éù²¨²â¾à
   Trig ¿ØÖÆ PA2 out
     Echo ½ÓÊÕ PA3 in   Echo Ϊ¸ßµçƽʱ£¬Æô¶¯¶¨Ê±Æ÷   Echo ΪµÍµçƽ£¬¹Ø±Õ¶¨Ê±Æ÷
*/
  double  get_distance(){
    //¶¨Ê±Æ÷¹é0 È·±£´Ó0¿ªÊ¼¼ÆÊý
    __HAL_TIM_SET_COUNTER(&htim7,0);

    __HAL_TIM_SET_AUTORELOAD(&htim7,50000-1);
        
    Led_off_all();
    //³¬Éù²¨´¥·¢ÐźÅ
    HAL_GPIO_WritePin(GPIOA,GPIO_PIN_2,1);
    HAL_Delay(100);//Trig¸ßµçƽʱ¼ä´óÓÚ10΢Ãë
    HAL_GPIO_WritePin(GPIOA,GPIO_PIN_2,0);//
    
    while(HAL_GPIO_ReadPin(GPIOA,GPIO_PIN_3)==0);//Åжϳ¬Éù²¨ÊÇ·ñ
        //·¢³öÉù²¨£¬Æô¶¯¶¨Ê±Æ÷
        HAL_TIM_Base_Start_IT(&htim7);
     
    while(HAL_GPIO_ReadPin(GPIOA,GPIO_PIN_3)==1);//Åжϳ¬Éù²¨ÊÇ·ñ
        //½ÓÊÕÉù²¨£¬¹Ø±Õ¶¨Ê±Æ÷
        HAL_TIM_Base_Stop(&htim7);
     
    //¼ÆËã³ö³¬Éù²¨µÄ´«Êäʱ¼ä£¬ÒÔ¼°²âµÃµÄ¾àÀë
    
        double  times;   //³¬Éù²¨µÄ´«ÊäµÄʱ¼ä
        double distance;//³¬Éù²¨²âµÃµÄ¾àÀë
      double count;   //¶¨Ê±Æ÷¼ÆÊýµÄʱ¼ä
        count  = __HAL_TIM_GET_COUNTER(&htim7);//¼ÆÊýµÄ´ÎÊý
        printf("
计数器计数的次数:%lf
",count);
        
        times = count*100;//¼ÆÊýµÄʱ¼ä = ¼ÆÊýµÄ´ÎÊý * ÿ¼Ó1µÄʱ¼ä
        
        distance = times * 340 / 1000000.0 * 100 / 2.0;
        
    return distance;
}

void main(){
　　printf("距离:%.2lf",get_distance());
}

运行的结果