STM32：用HC-SR04和STM32F103ZET6做超聲波測距

extern u8 TIM5CH1_CAPTURE_STA; //輸入捕獲狀態(tài) extern u16 TIM5CH1_CAPTURE_VAL; //輸入捕獲值 int main(void){  u32 temp=0; double ss=0; delay_init(); //延時函數初始化  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //設置NVIC中斷分組2:2位搶占優(yōu)先級，2位響應優(yōu)先級 uart_init(115200); //串口初始化為115200 TIM3_PWM_Init(71,199); //不分頻。PWM頻率=72000/(899+1)=80Khz TIM5_Cap_Init(0XFFFF,72-1); //以1Mhz的頻率計數 while(1) { delay_ms(10);// TIM_SetCompare2(TIM3,TIM_GetCapture2(TIM3)+1); TIM_SetCompare2(TIM3,63); if(TIM_GetCapture2(TIM3)==300)TIM_SetCompare2(TIM3,0);  if(TIM5CH1_CAPTURE_STA&0X80)//成功捕獲到了一次上升沿 { temp=TIM5CH1_CAPTURE_STA&0X3F; temp*=65536;//溢出時間總和 temp+=TIM5CH1_CAPTURE_VAL;//得到總的高電平時間 ss=temp*340/2/1000; printf("高電平時間:%d us\r\n",temp);//打印總的高點平時間 printf("測試距離為:%3.0f mm\r\n",ss); TIM5CH1_CAPTURE_STA=0;//開啟下一次捕獲 delay_ms(500); } }}

void TIM3_Int_Init(u16 arr,u16 psc){ TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; NVIC_InitTypeDef NVIC_InitStructure;
 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //時鐘使能
 TIM_TimeBaseStructure.TIM_Period = arr; //設置在下一個更新事件裝入活動的自動重裝載寄存器周期的值 計數到5000為500ms TIM_TimeBaseStructure.TIM_Prescaler =psc; //設置用來作為TIMx時鐘頻率除數的預分頻值 10Khz的計數頻率  TIM_TimeBaseStructure.TIM_ClockDivision = 0; //設置時鐘分割:TDTS = Tck_tim TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上計數模式 TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根據TIM_TimeBaseInitStruct中指定的參數初始化TIMx的時間基數單位
 TIM_ITConfig( //使能或者失能指定的TIM中斷 TIM3, //TIM2 TIM_IT_Update | //TIM 中斷源 TIM_IT_Trigger, //TIM 觸發(fā)中斷源 ENABLE //使能 ); NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn; //TIM3中斷 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //先占優(yōu)先級0級 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; //從優(yōu)先級3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_Cmd(TIM3, ENABLE); //使能TIMx外設 }
void TIM3_IRQHandler(void) //TIM3中斷{ if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) //檢查指定的TIM中斷發(fā)生與否:TIM 中斷源 { TIM_ClearITPendingBit(TIM3, TIM_IT_Update ); //清除TIMx的中斷待處理位:TIM 中斷源 LED1=!LED1; }}



//PWM輸出初始化//arr：自動重裝值//psc：時鐘預分頻數
void TIM3_PWM_Init(u16 arr,u16 psc){  GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure; 
 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE); //使能GPIO外設和AFIO復用功能模塊時鐘使能  GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射 TIM3_CH2->PB5 //用于TIM3的CH2輸出的PWM通過該LED顯示
 //設置該引腳為復用輸出功能,輸出TIM3 CH2的PWM脈沖波形 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //復用推挽輸出 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOB, &GPIO_InitStructure); //GPIO_WriteBit(GPIOA, GPIO_Pin_7,Bit_SET); // PA7上拉 
 TIM_TimeBaseStructure.TIM_Period = arr; //設置在下一個更新事件裝入活動的自動重裝載寄存器周期的值 80K TIM_TimeBaseStructure.TIM_Prescaler =psc; //設置用來作為TIMx時鐘頻率除數的預分頻值 不分頻 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //設置時鐘分割:TDTS = Tck_tim TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上計數模式 TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根據TIM_TimeBaseInitStruct中指定的參數初始化TIMx的時間基數單位   TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //選擇定時器模式:TIM脈沖寬度調制模式2 TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比較輸出使能 TIM_OCInitStructure.TIM_Pulse = 0; //設置待裝入捕獲比較寄存器的脈沖值 TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //輸出極性:TIM輸出比較極性高 TIM_OC2Init(TIM3, &TIM_OCInitStructure); //根據TIM_OCInitStruct中指定的參數初始化外設TIMx TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIMx在CCR2上的預裝載寄存器  TIM_ARRPreloadConfig(TIM3, ENABLE); //使能TIMx在ARR上的預裝載寄存器 
 TIM_Cmd(TIM3, ENABLE); //使能TIMx外設

}
//定時器5通道1輸入捕獲配置
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時鐘 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); //使能GPIOA時鐘  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; //PA0 清除之前設置  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD; //PA0 輸入  GPIO_Init(GPIOA, &GPIO_InitStructure); GPIO_ResetBits(GPIOA,GPIO_Pin_0); //PA0 下拉  //初始化定時器5 TIM5  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; //設置時鐘分割:TDTS = Tck_tim TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上計數模式 TIM_TimeBaseInit(TIM5, &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TIM5輸入捕獲參數 TIM5_ICInitStructure.TIM_Channel = TIM_Channel_1; //CC1S=01 選擇輸入端 IC1映射到TI1上 TIM5_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿捕獲 TIM5_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //映射到TI1上 TIM5_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //配置輸入分頻,不分頻 TIM5_ICInitStructure.TIM_ICFilter = 0x00;//IC1F=0000 配置輸入濾波器 不濾波 TIM_ICInit(TIM5, &TIM5_ICInitStructure);  //中斷分組初始化 NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn; //TIM3中斷 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; //先占優(yōu)先級2級 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; //從優(yōu)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(TIM5,TIM_IT_Update|TIM_IT_CC1,ENABLE);//允許更新中斷 ,允許CC1IE捕獲中斷   TIM_Cmd(TIM5,ENABLE ); //使能定時器5}
u8 TIM5CH1_CAPTURE_STA=0; //輸入捕獲狀態(tài) u16 TIM5CH1_CAPTURE_VAL; //輸入捕獲值
//定時器5中斷服務程序 void TIM5_IRQHandler(void){
 if((TIM5CH1_CAPTURE_STA&0X80)==0)//還未成功捕獲  {  if (TIM_GetITStatus(TIM5, TIM_IT_Update) != RESET)  {  if(TIM5CH1_CAPTURE_STA&0X40)//已經捕獲到高電平了 { if((TIM5CH1_CAPTURE_STA&0X3F)==0X3F)//高電平太長了 { TIM5CH1_CAPTURE_STA|=0X80;//標記成功捕獲了一次 TIM5CH1_CAPTURE_VAL=0XFFFF; }else TIM5CH1_CAPTURE_STA++; }  } if (TIM_GetITStatus(TIM5, TIM_IT_CC1) != RESET)//捕獲1發(fā)生捕獲事件 {  if(TIM5CH1_CAPTURE_STA&0X40) //捕獲到一個下降沿  {  TIM5CH1_CAPTURE_STA|=0X80; //標記成功捕獲到一次高電平脈寬 TIM5CH1_CAPTURE_VAL=TIM_GetCapture1(TIM5); TIM_OC1PolarityConfig(TIM5,TIM_ICPolarity_Rising); //CC1P=0 設置為上升沿捕獲 }else //還未開始,第一次捕獲上升沿 { TIM5CH1_CAPTURE_STA=0; //清空 TIM5CH1_CAPTURE_VAL=0; TIM_SetCounter(TIM5,0); TIM5CH1_CAPTURE_STA|=0X40; //標記捕獲到了上升沿 TIM_OC1PolarityConfig(TIM5,TIM_ICPolarity_Falling); //CC1P=1 設置為下降沿捕獲 }  }  }
 TIM_ClearITPendingBit(TIM5, TIM_IT_CC1|TIM_IT_Update); //清除中斷標志位
}