改了这个’超声波测距程序，用了后按键全都失效了

flysinking · 发表于 2017-12-9 21:43:30

#include "bsp.h"

#define HCSR04_TRIG     GPIO_Pin_7
#define HCSR04_ECHO     GPIO_Pin_7

u16 msHcCount = 0;//ms计数

void Hcsr04Init()
{  
    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;     //生成用于定时器设置的结构体
    GPIO_InitTypeDef GPIO_InitStructure;
      NVIC_InitTypeDef NVIC_InitStructure;
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOC, ENABLE);
    
        //IO初始化
    GPIO_InitStructure.GPIO_Pin =HCSR04_TRIG;       //发送电平引脚
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;        /* 设为输出口 */
      GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;        /* 设为推挽模式 */
      GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;    //推挽输出
    GPIO_Init(GPIOG, &GPIO_InitStructure);
    GPIO_ResetBits(GPIOC,HCSR04_TRIG);
    
    GPIO_InitStructure.GPIO_Pin =   HCSR04_ECHO;     //返回电平引脚
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;        /* 设为输出口 */
      GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;        /* 设为推挽模式 */
      GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; //推挽输出  
    GPIO_ResetBits(GPIOB,HCSR04_ECHO);    
    
            //定时器初始化使用基本定时器TIM6
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);   //使能对应RCC时钟
        //配置定时器基础结构体
        
        TIM_TimeBaseStructure.TIM_Period = (1000-1); //设置在下一个更新事件装入活动的自动重装载寄存器周期的值         计数到1000为1ms
        TIM_TimeBaseStructure.TIM_Prescaler =(72-1); //设置用来作为TIMx时钟频率除数的预分频值  1M的计数频率 1US计数
        TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;//不分频
        TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上计数模式
        TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位        
        
        TIM_ClearFlag(TIM4, TIM_FLAG_Update);   //清除更新中断，免得一打开中断立即产生中断
        TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE);    //打开定时器更新中断
        
        NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
    
       NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;             //选择串口1中断
        NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  //抢占式中断优先级设置为1
        NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;         //响应式中断优先级设置为1
        NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;        //使能中断
        NVIC_Init(&NVIC_InitStructure);
        TIM_Cmd(TIM4,DISABLE);    
}

//tips：static函数的作用域仅限于定义它的源文件内，所以不需要在头文件里声明
static void OpenTimerForHc()        //打开定时器
{
        TIM_SetCounter(TIM4,0);//清除计数
        msHcCount = 0;
        TIM_Cmd(TIM4, ENABLE);  //使能TIMx外设
}

static void CloseTimerForHc()        //关闭定时器
{
        TIM_Cmd(TIM4, DISABLE);  //使能TIMx外设
}

//定时器6中断服务程序
void TIM4_IRQHandler(void)   //TIM3中断
{
        if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)  //检查TIM3更新中断发生与否
        {
                TIM_ClearITPendingBit(TIM4, TIM_IT_Update  );  //清除TIMx更新中断标志
                msHcCount++;
        }
}

//获取定时器时间
u32 GetEchoTimer(void)
{
        u32 t = 0;
        t = msHcCount*1000;//得到MS
        t += TIM_GetCounter(TIM4);//得到US
          TIM4->CNT = 0;  //将TIM2计数寄存器的计数值清零
                bsp_DelayMS(50);
        return t;
}

//一次获取超声波测距数据两次测距之间需要相隔一段时间，隔断回响信号
//为了消除余震的影响，取五次数据的平均值进行加权滤波。
float Hcsr04GetLength(void )
{
        u32 t = 0;
        int i = 0;
        float lengthTemp = 0;
        float sum = 0;
        while(i!=5)
        {
        GPIO_SetBits(GPIOC,HCSR04_TRIG);    //发送口高电平输出
        bsp_DelayUS(20);
        GPIO_ResetBits(GPIOC,HCSR04_TRIG);
        while(GPIO_ReadInputDataBit(GPIOB,HCSR04_ECHO) == 0);      //等待接收口高电平输出
            OpenTimerForHc();        //打开定时器
            i = i + 1;
            while(GPIO_ReadInputDataBit(GPIOB,HCSR04_ECHO)  == 1);
            CloseTimerForHc();        //关闭定时器
            t = GetEchoTimer();        //获取时间,分辨率为1US
            lengthTemp = ((float)t/58.0);//cm
            sum = lengthTemp + sum ;
        
    }
        lengthTemp = (sum/5.0)-2;
        return lengthTemp;
}