STM32：用HC-SR04和STM32F103ZET6做超声波测距

extern u8 TIM5CH1_CAPTURE_STA; //输入捕获状态 extern u16 TIM5CH1_CAPTURE_VAL; //输入捕获值 int main(void){  u32 temp=0; double ss=0; delay_init(); //延时函数初始化  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //设置NVIC中断分组2:2位抢占优先级，2位响应优先级 uart_init(115200); //串口初始化为115200 TIM3_PWM_Init(71,199); //不分频。PWM频率=72000/(899+1)=80Khz TIM5_Cap_Init(0XFFFF,72-1); //以1Mhz的频率计数 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)//成功捕获到了一次上升沿 { temp=TIM5CH1_CAPTURE_STA&0X3F; temp*=65536;//溢出时间总和 temp+=TIM5CH1_CAPTURE_VAL;//得到总的高电平时间 ss=temp*340/2/1000; printf("高电平时间:%d us\r\n",temp);//打印总的高点平时间 printf("测试距离为:%3.0f mm\r\n",ss); TIM5CH1_CAPTURE_STA=0;//开启下一次捕获 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); //时钟使能
 TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值 计数到5000为500ms TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 10Khz的计数频率  TIM_TimeBaseStructure.TIM_ClockDivision = 0; //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(TIM3, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位
 TIM_ITConfig( //使能或者失能指定的TIM中断 TIM3, //TIM2 TIM_IT_Update | //TIM 中断源 TIM_IT_Trigger, //TIM 触发中断源 ENABLE //使能 ); NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn; //TIM3中断 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //先占优先级0级 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; //从优先级3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_Cmd(TIM3, ENABLE); //使能TIMx外设 }
void TIM3_IRQHandler(void) //TIM3中断{ if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) //检查指定的TIM中断发生与否:TIM 中断源 { TIM_ClearITPendingBit(TIM3, TIM_IT_Update ); //清除TIMx的中断待处理位:TIM 中断源 LED1=!LED1; }}



//PWM输出初始化//arr：自动重装值//psc：时钟预分频数
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外设和AFIO复用功能模块时钟使能  GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射 TIM3_CH2->PB5 //用于TIM3的CH2输出的PWM通过该LED显示
 //设置该引脚为复用输出功能,输出TIM3 CH2的PWM脉冲波形 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出 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; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值 80K TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 不分频 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //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(TIM3, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位   TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2 TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能 TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值 TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高 TIM_OC2Init(TIM3, &TIM_OCInitStructure); //根据TIM_OCInitStruct中指定的参数初始化外设TIMx TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIMx在CCR2上的预装载寄存器  TIM_ARRPreloadConfig(TIM3, ENABLE); //使能TIMx在ARR上的预装载寄存器 
 TIM_Cmd(TIM3, ENABLE); //使能TIMx外设

}
//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; //TIM3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((TIM5CH1_CAPTURE_STA&0X80)==0)//还未成功捕获  {  if (TIM_GetITStatus(TIM5, TIM_IT_Update) != RESET)  {  if(TIM5CH1_CAPTURE_STA&0X40)//已经捕获到高电平了 { if((TIM5CH1_CAPTURE_STA&0X3F)==0X3F)//高电平太长了 { TIM5CH1_CAPTURE_STA|=0X80;//标记成功捕获了一次 TIM5CH1_CAPTURE_VAL=0XFFFF; }else TIM5CH1_CAPTURE_STA++; }  } if (TIM_GetITStatus(TIM5, TIM_IT_CC1) != RESET)//捕获1发生捕获事件 {  if(TIM5CH1_CAPTURE_STA&0X40) //捕获到一个下降沿  {  TIM5CH1_CAPTURE_STA|=0X80; //标记成功捕获到一次高电平脉宽 TIM5CH1_CAPTURE_VAL=TIM_GetCapture1(TIM5); TIM_OC1PolarityConfig(TIM5,TIM_ICPolarity_Rising); //CC1P=0 设置为上升沿捕获 }else //还未开始,第一次捕获上升沿 { TIM5CH1_CAPTURE_STA=0; //清空 TIM5CH1_CAPTURE_VAL=0; TIM_SetCounter(TIM5,0); TIM5CH1_CAPTURE_STA|=0X40; //标记捕获到了上升沿 TIM_OC1PolarityConfig(TIM5,TIM_ICPolarity_Falling); //CC1P=1 设置为下降沿捕获 }  }  }
 TIM_ClearITPendingBit(TIM5, TIM_IT_CC1|TIM_IT_Update); //清除中断标志位
}