STM32单片机测量方波频率方法总结

//输入捕获初始化函数
void input_frequent_init(void)  //采用TIM4的Channel_1通道作为输入捕获通道
{
        //声明结构体变量，用来初始化定时器
	TIM_TimeBaseInitTypeDef TIM4_TimeBaseInitStructure;
	TIM_ICInitTypeDef TIM4_ICInitStructure;
	NVIC_InitTypeDef TIM4_NVIC_InitStructure;
	/* 开启定时器4时钟 */
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4,ENABLE);	 
	TIM_ClearITPendingBit(TIM4,TIM_IT_Update|TIM_IT_CC1); //清除捕获和中断标志位
	
	TIM4_TimeBaseInitStructure.TIM_Period = 0xffff;	 //设定计数器自动重装值（设置为最大）	
	TIM4_TimeBaseInitStructure.TIM_Prescaler = 1;   //设置分频系数
	TIM4_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;	  //设置时钟分割:TDTS = Tck_tim
	TIM4_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;	 //TIM向上计数模式
	TIM_TimeBaseInit(TIM4,&TIM4_TimeBaseInitStructure);//根据结构体参量初始化定时器
	
	TIM4_ICInitStructure.TIM_Channel = TIM_Channel_1; //选择输入捕获的输入端，IC1映射到TI1上 
	TIM4_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //设置为上升沿捕获
	TIM4_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //映射到TI1上
	TIM4_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //配置输入分频，不分频
	TIM4_ICInitStructure.TIM_ICFilter = 0x00; //IC1F=0000 配置输入滤波器，此处不滤波
	TIM_ICInit(TIM4, &TIM4_ICInitStructure); //初始化TIM4通道1	
	
	//中断分组初始化
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
	TIM4_NVIC_InitStructure.NVIC_IRQChannel=TIM4_IRQn;	//打开TIM4的全局中断
	TIM4_NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1;	//抢占优先级配置为1
	TIM4_NVIC_InitStructure.NVIC_IRQChannelSubPriority=1; //响应优先级配置为1
	TIM4_NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;	  //使能
	NVIC_Init(&TIM4_NVIC_InitStructure);   //初始化中断
	
	TIM_Cmd(TIM4,ENABLE); //使能中断
	TIM_ITConfig(TIM4, TIM_IT_Update|TIM_IT_CC1, ENABLE );	//使能捕获和更新中断
}

TIM4_ICInitStructure.TIM_ICFilter = 0x00; //IC1F=0000 配置输入滤波器，此处不滤波

void TIM4_IRQHandler()	  //输入捕获中断函数
{
	static u8 state;  //存储捕获状态，state=0表示未捕获到第一个上升沿，state=1表示已经捕获到第一个上升沿
	static u32 TIM4CH1_CAPTURE; //存储TIM4计数寄存器溢出次数
	u32 timecount;  //存储总的计数次数
	
	if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)  //发生计数器溢出更新中断	
	{
		TIM_ClearITPendingBit(TIM4, TIM_IT_CC1|TIM_IT_Update);  //清除中断标志位
		if(state==1) //在捕获到第一个上升沿后
			TIM4CH1_CAPTURE++;	//溢出次数加一				
	}	
	
	if(TIM_GetITStatus(TIM4,TIM_IT_CC1)!=RESET)  //产生输入捕获中断
        {
               TIM_ClearITPendingBit(TIM4, TIM_IT_CC1|TIM_IT_Update); //清除中断标志位
               if(state==0)    //未捕获到第一个上升沿
	        {
		    state=1;  //置1
		    TIM_SetCounter(TIM4,0);   //将计数器清零     
	        }
		else if(state==1)  //已经捕获到第一个上升沿
               {
                    state=0;  //置0
                    timecount=TIM_GetCapture1(TIM4)+TIM4CH1_CAPTURE*65536;   //计算两个上升沿之间的总计数
		    TIM4CH1_CAPTURE=0; //清零溢出次数
		    TIM_SetCounter(TIM4,0);  //清零计数器
		    frequent_input=36000000.0/timecount;   //计算频率
		}
   }
}

void TIM5_IRQHandler()	  
{
		
	if((TIM5CH1_CAPTURE_STA&0X80)==0)//还未成功捕获
	{
		if (TIM_GetITStatus(TIM5, TIM_IT_Update) != RESET)	
		{
			if(TIM5CH1_CAPTURE_STA&0X20) //已经捕获到高电平
			{
				if((TIM5CH1_CAPTURE_STA&0x1f)==0x1f)//高电平时间太长了
				{	
					TIM5CH1_CAPTURE_STA|=0x80;	//标记成功捕获一次		
				}
				else
				{
					TIM5CH1_CAPTURE_STA++;	//溢出次数加1
				}
			}
		}	
	}
	if (TIM_GetITStatus(TIM5, TIM_IT_CC4) != RESET) //发生捕获事件
	{
		if((TIM5CH1_CAPTURE_STA&0X20)&&(!(TIM5CH1_CAPTURE_STA&0X40))) //已经捕获到上升沿
		{
			TIM5CH1_CAPTURE_STA|=0X40; //标记成功捕获一次下降沿 
			TIM5CH1_CAPTURE_VAL1=TIM_GetCapture4(TIM5)+(TIM5CH1_CAPTURE_STA&0X1f)*65536; //获得TIM5捕获通道一的捕获值（对应高电平时间）
			TIM_SetCounter(TIM5,0);  //清零计数器
			TIM_OC4PolarityConfig(TIM5,TIM_ICPolarity_Rising); //设置为上升沿捕获
			TIM5CH1_CAPTURE_STA&=0Xe0;  //溢出次数清零
		}
		else if((TIM5CH1_CAPTURE_STA&0X20)==0)  //未捕获到上升沿
		{
			TIM5CH1_CAPTURE_STA=0;    //清零标志位及溢出次数
			TIM5CH1_CAPTURE_VAL1=0;   //清零高电平计数
			TIM5CH1_CAPTURE_VAL2=0;	  //清零低电平计数		
			TIM_SetCounter(TIM5,0);   //清零TIM5计数寄存器			
                        TIM5CH1_CAPTURE_STA|=0X20; //置标志位
			TIM_OC4PolarityConfig(TIM5,TIM_ICPolarity_Falling); //设置为下降沿捕获
		}
		else if((TIM5CH1_CAPTURE_STA&0X40)&&(!(TIM5CH1_CAPTURE_STA&0X80))) //已经捕获到下降沿
		{
			TIM5CH1_CAPTURE_VAL2=TIM_GetCapture4(TIM5)+(TIM5CH1_CAPTURE_STA&0X1f)*65536;//低电平计数（对应低电平时间）
			TIM5CH1_CAPTURE_STA|=0X80;  //置标志位
		}			
	}
	TIM_ClearITPendingBit(TIM5, TIM_IT_CC4|TIM_IT_Update); //清中断标志位
}

u8 TIM5CH1_CAPTURE_STA; //
u16 TIM5CH1_CAPTURE_VAL1;//
u16 TIM5CH1_CAPTURE_VAL2;//

float frequent;
float duty;

int main()
{		
        input_duty_init();	
	while(1)
	{
                if((TIM5CH1_CAPTURE_STA&0x80))	  //
                {
                       duty=(float)TIM5CH1_CAPTURE_VAL1/(TIM5CH1_CAPTURE_VAL1+TIM5CH1_CAPTURE_VAL2 );//计算占空比
                       frequent+=500000.0/(TIM5CH1_CAPTURE_VAL1+TIM5CH1_CAPTURE_VAL2 );//计算频率
                       TIM5CH1_CAPTURE_STA=0; // 清零标志位
                }
	}
}