- #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時鐘
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); //使能GPIOB時鐘
-
- /*TRIG觸發信號*/
- GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
- GPIO_InitStructure.GPIO_Mode=GPIO_Mode_Out_PP; //推挽輸出
- GPIO_InitStructure.GPIO_Pin=GPIO_Pin_8;
- GPIO_Init(GPIOB, &GPIO_InitStructure);
- GPIO_ResetBits(GPIOB,GPIO_Pin_8);
-
- /*ECOH回響信號*/
- GPIO_InitStructure.GPIO_Mode=GPIO_Mode_IN_FLOATING; //浮空輸入
- GPIO_InitStructure.GPIO_Pin=GPIO_Pin_9;
- GPIO_Init(GPIOB, & GPIO_InitStructure);
- GPIO_ResetBits(GPIOB,GPIO_Pin_9);
- //初始化定時器4 TIM4
- TIM_TimeBaseStructure.TIM_Period = arr; //設定計數器自動重裝值
- TIM_TimeBaseStructure.TIM_Prescaler =psc; //預分頻器
- TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //不分頻
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上計數模式
- TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure); //根據TIM_TimeBaseInitStruct中指定的參數初始化TIMx的時間基數單位
-
- //初始化TIM4輸入捕獲參數
- TIM4_ICInitStructure.TIM_Channel = TIM_Channel_4; //CC4S=01 選擇輸入端 IC4映射到TI4上
- TIM4_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿捕獲
- TIM4_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //映射到TI4上
- TIM4_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //配置輸入分頻,不分頻
- TIM4_ICInitStructure.TIM_ICFilter = 0x03;//IC4F=0000 配置輸入濾波器 不濾波
- TIM_ICInit(TIM4, &TIM4_ICInitStructure);
-
- //中斷分組初始化
- NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn; //TIM4中斷
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //先占優先級0級
- NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; //從優先級0級
- NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能
- NVIC_Init(&NVIC_InitStructure); //根據NVIC_InitStruct中指定的參數初始化外設NVIC寄存器
-
- TIM_ITConfig(TIM4,TIM_IT_Update|TIM_IT_CC4,ENABLE);//允許更新中斷 ,允許CC4IE捕獲中斷
-
- TIM_Cmd(TIM4,ENABLE);
-
- }
- u8 TIM4CH4_CAPTURE_STA=0; //輸入捕獲狀態
- u16 TIM4CH4_CAPTURE_VAL; //輸入捕獲值-----用來記錄捕獲到下降沿的時候 TIM4 _CNT的值
-
- //定時器4中斷服務程序
- void TIM4_IRQHandler(void)
- {
- if((TIM4CH4_CAPTURE_STA&0X80)==0)//還未成功捕獲
- {
- if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)
-
- {
- if(TIM4CH4_CAPTURE_STA&0X40)//已經捕獲到高電平了
- {
- if((TIM4CH4_CAPTURE_STA&0X3F)==0X3F)//高電平太長了
- {
- TIM4CH4_CAPTURE_STA|=0X80;//標記成功捕獲了一次
- TIM4CH4_CAPTURE_VAL=0XFFFF;
- }else TIM4CH4_CAPTURE_STA++;
- }
- }
- if (TIM_GetITStatus(TIM4, TIM_IT_CC4) != RESET)//捕獲4發生捕獲事件
- {
- if(TIM4CH4_CAPTURE_STA&0X40) //捕獲到一個下降沿
- {
- TIM4CH4_CAPTURE_STA|=0X80; //標記成功捕獲到一次上升沿
- TIM4CH4_CAPTURE_VAL=TIM_GetCapture4(TIM4);
- TIM_OC4PolarityConfig(TIM4,TIM_ICPolarity_Rising); //CC4P=0 設置為上升沿捕獲
- }else //還未開始,第一次捕獲上升沿
- {
- TIM4CH4_CAPTURE_STA=0; //清空
- TIM4CH4_CAPTURE_VAL=0;
- TIM_SetCounter(TIM4,0);
- TIM4CH4_CAPTURE_STA|=0X40; //標記捕獲到了上升沿
- TIM_OC4PolarityConfig(TIM4,TIM_ICPolarity_Falling); //CC4P=1 設置為下降沿捕獲
- }
- }
- }
- TIM_ClearITPendingBit(TIM4, TIM_IT_CC4|TIM_IT_Update); //清除中斷標志位
- }
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