- #include "timer.h"
- #include "usart.h"
- #include "sys.h"
- void TIM4_Cap_Init(u16 arr,u16 psc)
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- TIM_ICInitTypeDef TIM4_ICInitStructure;
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- NVIC_InitTypeDef NVIC_InitStructure;
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE); //使能TIM4时钟
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); //使能GPIOB时钟
-
- /*TRIG触发信号*/
- GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
- GPIO_InitStructure.GPIO_Mode=GPIO_Mode_Out_PP; //推挽输出
- GPIO_InitStructure.GPIO_Pin=GPIO_Pin_8;
- GPIO_Init(GPIOB, &GPIO_InitStructure);
- GPIO_ResetBits(GPIOB,GPIO_Pin_8);
-
- /*ECOH回响信号*/
- GPIO_InitStructure.GPIO_Mode=GPIO_Mode_IN_FLOATING; //浮空输入
- GPIO_InitStructure.GPIO_Pin=GPIO_Pin_9;
- GPIO_Init(GPIOB, & GPIO_InitStructure);
- GPIO_ResetBits(GPIOB,GPIO_Pin_9);
- //初始化定时器4 TIM4
- 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; //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
-
- //初始化TIM4输入捕获参数
- TIM4_ICInitStructure.TIM_Channel = TIM_Channel_4; //CC4S=01 选择输入端 IC4映射到TI4上
- TIM4_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿捕获
- TIM4_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //映射到TI4上
- TIM4_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //配置输入分频,不分频
- TIM4_ICInitStructure.TIM_ICFilter = 0x03;//IC4F=0000 配置输入滤波器 不滤波
- TIM_ICInit(TIM4, &TIM4_ICInitStructure);
-
- //中断分组初始化
- NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn; //TIM4中断
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //先占优先级0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(TIM4,TIM_IT_Update|TIM_IT_CC4,ENABLE);//允许更新中断 ,允许CC4IE捕获中断
-
- TIM_Cmd(TIM4,ENABLE);
-
- }
- u8 TIM4CH4_CAPTURE_STA=0; //输入捕获状态
- u16 TIM4CH4_CAPTURE_VAL; //输入捕获值-----用来记录捕获到下降沿的时候 TIM4 _CNT的值
-
- //定时器4中断服务程序
- void TIM4_IRQHandler(void)
- {
- if((TIM4CH4_CAPTURE_STA&0X80)==0)//还未成功捕获
- {
- if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)
-
- {
- if(TIM4CH4_CAPTURE_STA&0X40)//已经捕获到高电平了
- {
- if((TIM4CH4_CAPTURE_STA&0X3F)==0X3F)//高电平太长了
- {
- TIM4CH4_CAPTURE_STA|=0X80;//标记成功捕获了一次
- TIM4CH4_CAPTURE_VAL=0XFFFF;
- }else TIM4CH4_CAPTURE_STA++;
- }
- }
- if (TIM_GetITStatus(TIM4, TIM_IT_CC4) != RESET)//捕获4发生捕获事件
- {
- if(TIM4CH4_CAPTURE_STA&0X40) //捕获到一个下降沿
- {
- TIM4CH4_CAPTURE_STA|=0X80; //标记成功捕获到一次上升沿
- TIM4CH4_CAPTURE_VAL=TIM_GetCapture4(TIM4);
- TIM_OC4PolarityConfig(TIM4,TIM_ICPolarity_Rising); //CC4P=0 设置为上升沿捕获
- }else //还未开始,第一次捕获上升沿
- {
- TIM4CH4_CAPTURE_STA=0; //清空
- TIM4CH4_CAPTURE_VAL=0;
- TIM_SetCounter(TIM4,0);
- TIM4CH4_CAPTURE_STA|=0X40; //标记捕获到了上升沿
- TIM_OC4PolarityConfig(TIM4,TIM_ICPolarity_Falling); //CC4P=1 设置为下降沿捕获
- }
- }
- }
- TIM_ClearITPendingBit(TIM4, TIM_IT_CC4|TIM_IT_Update); //清除中断标志位
- }
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