流程精简：1、IC配置（设置捕获模式，通道、使能捕获中断）

                        2、中断向量的嵌套，以及对应的PIO口配置

                        3、中断服务函数的配置

1、IC配置（设置捕获模式，通道、使能捕获中断）

void  TIM3_Configuration(void) //定时器3初始化;输入捕获设置                                                           

{        TIM_ICInitTypeDef  TIM_ICInitStructure;

         RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

         TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;//通道选择

         TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;        //上升沿触发

         TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;      //管教与寄存器的对应关系

         TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //分频器

         TIM_ICInitStructure.TIM_ICFilter = 0x0;            //滤波设置

         TIM_PWMIConfig(TIM3, &TIM_ICInitStructure);     //PWM输入模式初始化

         //TIM_ICInit(TIM3, &TIM_ICInitStructure);

         TIM_SelectInputTrigger(TIM3, TIM_TS_TI2FP2);     //选择时钟触发源

         TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Reset);          //触发方式

         TIM_SelectMasterSlaveMode(TIM3, TIM_MasterSlaveMode_Enable);        //启动定时器的被动触发

         TIM_Cmd(TIM3, ENABLE);                 //启动tim2

         TIM_ITConfig(TIM3, TIM_IT_CC2, ENABLE);   //打开中断

}

2、中断向量的嵌套，以及对应的PIO口配置

void NVIC_Configuration(void)

{        NVIC_InitTypeDef NVIC_InitStructure;

         //为EXTI_Line9使能并配置中断向量

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //设置优先级分组：先占优先级2位,从优先级2位

         NVIC_InitStructure.NVIC_IRQChannel=TIM3_IRQn ;

         NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;                           //抢占优先级0

         NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;                                 //响应优先级1

         NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;                                         //允许中断

         NVIC_Init(&NVIC_InitStructure); //写入设置}

3、中断服务函数的配置

void TIM3_IRQHandler(void)

{    

         LCD12864_Put_Num(4,0,132454);

TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);//中断的重点，进入后要清除相应的标志位以跳出中断

         i++;

         IC2Value=TIM_GetCapture2(TIM3);//捕获的是周期

         IC1Value=TIM_GetCapture1(TIM3);//捕获的是高电平

         if(i==500)

         {          i=0;

           LCD12864_Put_Num(1,0,72000000/IC2Value);

           LCD12864_Put_Num(2,0,72000000/IC1Value);

         }

}