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还有一点问题就是最大测17cm,后面就显示不出,希望大神们指导下,我是个小白
- #include "timer.h"
- #include "led.h"
- #include "usart.h"
- #include "delay.h"
- //通用定时器中断初始化
- //这里时钟选择为APB1的2倍,而APB1为36M
- //arr:自动重装值。
- //psc:时钟预分频数
- //定时器5通道1输入捕获配置
- TIM_ICInitTypeDef TIM5_ICInitStructure;
- void TIM5_Cap_Init(u16 arr,u16 psc)
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- NVIC_InitTypeDef NVIC_InitStructure;
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE); //使能TIM5时钟
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); //使能GPIOA时钟
-
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; //PA0 清除之前设置
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD; //PA0 输入
- GPIO_Init(GPIOA, &GPIO_InitStructure);
- GPIO_ResetBits(GPIOA,GPIO_Pin_0); //PA0 下拉
-
- //初始化定时器5 TIM5
- TIM_TimeBaseStructure.TIM_Period = arr; //设定计数器自动重装值
- TIM_TimeBaseStructure.TIM_Prescaler =psc; //预分频器
- TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //设置时钟分割:TDTS = Tck_tim
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式
- TIM_TimeBaseInit(TIM5, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位
-
- //初始化TIM5输入捕获参数
- TIM5_ICInitStructure.TIM_Channel = TIM_Channel_1; //CC1S=01 选择输入端 IC1映射到TI1上
- TIM5_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿捕获
- TIM5_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //映射到TI1上
- TIM5_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //配置输入分频,不分频
- TIM5_ICInitStructure.TIM_ICFilter = 0x00;//IC1F=0000 配置输入滤波器 不滤波
- TIM_ICInit(TIM5, &TIM5_ICInitStructure);
-
- //中断分组初始化
- NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn; //TIM5中断
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; //先占优先级2级
- NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; //从优先级0级
- NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能
- NVIC_Init(&NVIC_InitStructure); //根据NVIC_InitStruct中指定的参数初始化外设NVIC寄存器
-
- TIM_ITConfig(TIM5,TIM_IT_Update|TIM_IT_CC1,ENABLE);//允许更新中断 ,允许CC1IE捕获中断
-
- TIM_Cmd(TIM5,ENABLE ); //使能定时器5
-
- }
- u8 TIM5CH1_CAPTURE_STA=0; //输入捕获状态
- u16 TIM5CH1_CAPTURE_VAL; //输入捕获值
- //定时器5中断服务程序
- void TIM5_IRQHandler(void)
- {
- if(TIM_GetITStatus(TIM5, TIM_IT_CC1) != RESET)
- {
- if(TIM5CH1_CAPTURE_STA==1)
- {
- TIM5CH1_CAPTURE_VAL=TIM_GetCapture1(TIM5);
- printf("探测距离为:%.2f cm\r\n",TIM5CH1_CAPTURE_VAL*17/1000.0);
- TIM5CH1_CAPTURE_STA=0;
- TIM_OC1PolarityConfig(TIM5,TIM_ICPolarity_Rising); //CC1P=0 设置为上升沿捕获
- }
- else
- {
- TIM5CH1_CAPTURE_VAL = 0;
- TIM5CH1_CAPTURE_STA =1;
- TIM_SetCounter(TIM5,0);
- TIM_OC1PolarityConfig(TIM5,TIM_ICPolarity_Falling); //CC1P=1 设置为下降沿捕获
- TIM_Cmd(TIM5,ENABLE);
- }
- }
- TIM_ClearITPendingBit(TIM5, TIM_IT_CC1|TIM_IT_Update); //清除中断标志位
-
- }
复制代码
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