输入捕获的超声波测距一直为0

Question

最近在搞一个rct6超声波测距有关的项目 结果调了一天 测出来的距离一直都是0 一开始是用外部中断 后来改成了输入捕获 结果还是输出0
这是定时器输入捕获的代码

void TIM3IC_Init()
{
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    
    GPIO_InitTypeDef  GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA,&GPIO_InitStructure);
    
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Mode =GPIO_Mode_Out_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

    TIM_InternalClockConfig(TIM3);
    
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
    TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInitStructure.TIM_Period = 65535 - 1;
    TIM_TimeBaseInitStructure.TIM_Prescaler = 720 - 1 ;
    TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;
    
    TIM_ICInitTypeDef TIM_ICInitStructure;
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
    TIM_ICInitStructure.TIM_ICFilter = 0xF;
    TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
    TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
    TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
    TIM_PWMIConfig(TIM3,&TIM_ICInitStructure);
    
    
    TIM_SelectInputTrigger(TIM3,TIM_TS_TI1FP1);
    TIM_SelectSlaveMode(TIM3,TIM_SlaveMode_Reset);
    
    TIM_ITConfig(TIM3,TIM_IT_CC2|TIM_IT_CC1,ENABLE);
    TIM_SetCounter(TIM2,0);
    
    
    TIM_TimeBaseInit(TIM3,&TIM_TimeBaseInitStructure);

    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_Init(&NVIC_InitStructure);
    
  TIM_Cmd(TIM3,ENABLE);
    
}

void TIM3_IRQHandler()
{

    if(TIM_GetITStatus(TIM3,TIM_IT_CC2)!=RESET)
        {           
           Distance = (TIM_GetCapture2(TIM3)+1) * 340/20000.0; 
             Flag = 1;
       //printf("Distance = %f m\r\n",Distance);            
        }
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
}

这是配置超声波引脚的代码

float Distance;
int Flag = 1,ICAP1value,ICAP2value;
 
 
void HC_SR04_init(void)
{
    GPIO_InitTypeDef  GPIO_InitStructure;
 
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);     
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;                 
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;         
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;         
    GPIO_Init(GPIOA, &GPIO_InitStructure);                                         
 
}
    

void HC_SR04_start(void)
{
    GPIO_SetBits(GPIOA,GPIO_Pin_4);
    Delay_us(20);
    GPIO_ResetBits(GPIOA,GPIO_Pin_4);
    Delay_ms(60);
}

输出结果一直为0 串口方面测试过是没问题的 引脚也可以正常输出 但不知道自己的逻辑错在哪了 希望带佬们指导一下

Answer 1

我的代码经测试没有问题，可以借鉴：

#include "stm32f10x.h"    //在该头文件中默认定义系统时钟为72M
#include "delay.h"
#include "sys.h"
#include "usart.h"
#include "ultrasonic.h" 
    


 int main(void)
 {        
   RCC_Configuration();
    delay_init();             //延时函数初始化      
    NVIC_Configuration();      //设置NVIC中断分组2:2位抢占优先级，2位响应优先级
    uart1_init(9600);     //串口初始化为9600
    Ultrasonic_GPIO_Conf();
    EXTI_Configuration();
    Timer_Configuration();
    init_Ultrasonic();
     while(1)
    {
//        USART1_SendData('*');
//      USART1_SendData('\r');
//      USART1_SendData('\n');
//        Showstring("Distance:");
//      delay_ms(800);
//        GPIO_WriteBit(GPIOA, GPIO_Pin_15, (BitAction)0);
    }     
 }

ultrasonic.c

#include "stm32f10x.h"    //在该头文件中默认定义系统时钟为72M
#include "delay.h"
#include "sys.h"
#include "usart.h"
#include "ultrasonic.h"

unsigned char SFlag=0;
unsigned long Distance=0;
    
void Ultrasonic_GPIO_Conf(void)           
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);//必须先开启复用时钟，然后才能重映射或者外中断
    GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable , ENABLE);  // 改变指定管脚的映射 GPIO_Remap_SWJ_JTAGDisable ，JTAG-DP 禁用 + SW-DP 使能
    
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);          //发射引脚初始化

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);          //接收引脚初始化
    
}
void Timer_Configuration(void)
{
  TIM_TimeBaseInitTypeDef   TIM_TimeBaseStructure;
  NVIC_InitTypeDef NVIC_InitStructure; 
    
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
    
  TIM_DeInit(TIM1);
  TIM_TimeBaseStructure.TIM_Period=20000;         //ARR的值, 一次计时200ms    最大值为34米
  TIM_TimeBaseStructure.TIM_Prescaler=719;         //719+1=720
  TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; //采样分频
  TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式
  TIM_TimeBaseInit(TIM1,&TIM_TimeBaseStructure);

  TIM1->DIER|=1<<0;   //允许更新中断                
  TIM1->DIER|=1<<6;   //允许触发中断       

  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4); 
 
  NVIC_InitStructure.NVIC_IRQChannel = TIM1_UP_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;       
  NVIC_Init(&NVIC_InitStructure);
}
//定时器溢出中断服务程序     
void TIM1_UP_IRQHandler(void)
{          
//USART1_SendData('1');    
    if(TIM1->SR&0X0001)//溢出中断
    {    
      Showstring("Out of distance! ");    
      GPIO_WriteBit(GPIOA, GPIO_Pin_15, (BitAction)1);//高电平触发 
        delay_us(20);//如果不加延时，系统不稳定
       GPIO_WriteBit(GPIOA, GPIO_Pin_15, (BitAction)0);
      TIM_SetCounter(TIM1,0);
      TIM_Cmd(TIM1, ENABLE);
      SFlag=0;     //取消当前上升沿标志                                                                
    }                   
    TIM1->SR&=~(1<<0);//清除中断标志位         
}

    unsigned long d=3400;
    unsigned char i=0;
void EXTI15_10_IRQHandler(void)         //当前是设置的电平变化就进入中断
{
//    USART1_SendData('Q');
   if(EXTI_GetITStatus(EXTI_Line12) != RESET)
   {
         
     if(GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_12)==1)      //接收到上升沿，开始计时
     {
           TIM_SetCounter(TIM1,0);
        TIM_Cmd(TIM1, ENABLE);
        SFlag=1;         //表示经过了上升沿
     }
     else if(GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_12)==0 && SFlag==1)
     {
             TIM_Cmd(TIM1, DISABLE);
             Distance=(int)(((float)TIM_GetCounter(TIM1))*1.7);    //如果测距是2.5m则需15ms
             if(d>Distance)       //只要最小值
                 d=Distance;
             i++;
             if(i==3)                 //测量三次，只要最小值
             {
                 i=0;
                 Showstring("Distance:");
                 Show_u16(d);
                 Showstring("mm  ");
                 USART1_SendData('\r');
                 USART1_SendData('\n');
                 delay_ms(300);
                 d=34000;
                }
                GPIO_WriteBit(GPIOA, GPIO_Pin_15, (BitAction)1);//高电平触发 
                delay_us(20);//如果不加延时，系统不稳定
                GPIO_WriteBit(GPIOA, GPIO_Pin_15, (BitAction)0);
                TIM_SetCounter(TIM1,0);
                TIM_Cmd(TIM1, ENABLE);
                SFlag=0;
      }
      EXTI_ClearITPendingBit(EXTI_Line12);
   }
}
void init_Ultrasonic(void)
{
     delay_ms(100); //为超声波稳定争取时间
    GPIO_WriteBit(GPIOA, GPIO_Pin_15, (BitAction)0);//先设置成低电平
    delay_ms(100);//
    GPIO_WriteBit(GPIOA, GPIO_Pin_15, (BitAction)1); //高电平触发
    delay_us(40);//高电平至少10us
    GPIO_WriteBit(GPIOA, GPIO_Pin_15, (BitAction)0);//降回低电平
    TIM_SetCounter(TIM1,0);
    TIM_Cmd(TIM1, ENABLE);
}
void EXTI_Configuration(void)
{
  EXTI_InitTypeDef   EXTI_InitStructure;
  NVIC_InitTypeDef   NVIC_InitStructure;

  /* Enable GPIOB clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
/* Enable AFIO clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
  /* Configure PB.09 pin as input floating */
    
  /* Connect EXTI9 Line to PB.09 pin */
  GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource12);
  /* Configure EXTI9 line */
  EXTI_InitStructure.EXTI_Line = EXTI_Line12;
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger =EXTI_Trigger_Rising_Falling ;//EXTI_Trigger_Falling  EXTI_Trigger_Rising_Falling
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);
 
  /* Enable and set EXTI9_5 Interrupt to the lowest priority */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);
  NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;//最高优先级
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);
}