stm32超声波测距tim2捕获模式.rar 6.06MB RAR 59次下载

/*定时器初始化*/
     
/*定义一个TIM_TimeBaseInitTypeDef 类型的结构体，名字叫TIM_TimeBaseStructure*/
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
/*定义一个TIM_ICInitTypeDef 类型的结构体，名字叫TIM_ICInitStructure*/
TIM_ICInitTypeDef  TIM_ICInitStructure;
/* 定时器基本设置：*/
/*计数器每次计数的最高值*/
TIM_TimeBaseStructure.TIM_Period = 0xffff;
/* 时钟预分频数 72M/1+1 = 36M   所采集的频率的最小值应该为 36M/60000=600HZ*/
TIM_TimeBaseStructure.TIM_Prescaler = 720;
/* 采样分频 */
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
/* 向上计数模式 */
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
/*调用库函数，初始化TIM2*/
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
/*输入捕获设置*/
/*设置频道1，即PA0*/
TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
/*设置捕获模式为上升沿捕获*/
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
/*设置输入1与IC1相连*/
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
/*设置TIM捕获在捕获输入上每探测到一个边沿执行一次*/
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
/*设置输入比较滤波器*/
TIM_ICInitStructure.TIM_ICFilter = 0x00;
/*初始化输入捕获设置*/
TIM_ICInit(TIM2, &TIM_ICInitStructure);
     
TIM_Cmd(TIM2, ENABLE);
TIM_ITConfig(TIM2, TIM_IT_CC1, ENABLE);
/*定时器初始化*/

void NVIC_Config(void)
{
    /*定义一个NVIC_InitTypeDef 类型的结构体，名字叫NVIC_InitStructure*/
    NVIC_InitTypeDef NVIC_InitStructure;
    /**********************************************
    NVIC_PriorityGroup_0：先占优先级0位从优先级4位
    NVIC_PriorityGroup_1：先占优先级1位从优先级3位
    NVIC_PriorityGroup_2：先占优先级2位从优先级2位
    NVIC_PriorityGroup_3：先占优先级3位从优先级1位
    NVIC_PriorityGroup_4：先占优先级4位从优先级0位
    ***********************************************/
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
    /*配置选中的中断向量*/
    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;; //TIM2捕获比较中断
     
    /*设置了成员NVIC_IRQChannel中的先占优先级*/
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
     
    /*设置了成员NVIC_IRQChannel中的响应优先级*/
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
     
    /*使能中断向量*/
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
     
    /*调用库函数，初始化中断向量*/
    NVIC_Init(&NVIC_InitStructure);
     
     
}
void TIM2_GPIO_Config(void)
{
    /*定义一个GPIO_InitTypeDef 类型的结构体，名字叫GPIO_InitStructure*/
    GPIO_InitTypeDef GPIO_InitStructure;
    /*开启TIM2的时钟*/
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    /*开启GPIOA的时钟*/
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA , ENABLE);
    /*选择PA0引脚*/
    GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_0 ;
    /*引脚模式设置为下拉输入*/
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
    /*设置引脚速度*/
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    /*初始化所设置的PA管脚*/
    GPIO_Init(GPIOA, &GPIO_InitStructure);
}

unsigned int Tim_RIsing_count = 0; //上升沿计数
unsigned int Tim_Falling_count = 0;//下降沿计数
     
static char Time_State = RIsing;
     
void TIM2_IRQHandler(void)       //中断函数
{
    /*检测中断标志位*/
    if (TIM_GetITStatus(TIM2, TIM_IT_CC1) == SET)       /*重置中断标志位*/
        TIM_ClearITPendingBit(TIM2, TIM_IT_CC1);
     
    if (Time_State == RIsing)
    {
        Time_State = Falling;
        TIM_OC1PolarityConfig(TIM2, TIM_ICPolarity_Falling);
        TIM2->CNT = 0x04;
        Tim_RIsing_count = TIM_GetCapture1(TIM2);
    }
    else
    {
        Time_State = RIsing;
        TIM_OC1PolarityConfig(TIM2, TIM_ICPolarity_Rising);
        Tim_Falling_count = TIM_GetCapture1(TIM2);
    }
    //TIM_UpdateRequestConfig(TIM2, TIM_UpdateSource_Global); 中断源
     
}