stm32f103c8超声波测距代码

STM32F103C8是一款常见的32位微控制器，可以用于实现超声波测距功能。以下是一个基本的超声波测距代码，你可以根据自己的需求进行修改：

#include "stm32f10x.h"
#include "delay.h"
#include "usart.h"

#define TRIG_PORT   GPIOA
#define TRIG_PIN    GPIO_Pin_1
#define ECHO_PORT   GPIOA
#define ECHO_PIN    GPIO_Pin_2

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

    //定时器TIM3初始化
    TIM_TimeBaseStructure.TIM_Period = arr; //自动重装载值
    TIM_TimeBaseStructure.TIM_Prescaler =psc; //定时器分频
    TIM_TimeBaseStructure.TIM_ClockDivision = 0; //时钟分割
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数模式
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //初始化定时器3

    TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE ); //允许定时器3更新中断
    TIM_Cmd(TIM3, ENABLE); //使能定时器3

    NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;  //定时器3中断
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  //抢占优先级0
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;  //子优先级3
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

}

void EXTI_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    EXTI_InitTypeDef EXTI_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);

    GPIO_InitStructure.GPIO_Pin = ECHO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_Init(ECHO_PORT, &GPIO_InitStructure);

    GPIO_EXTILineConfig(GPIO_PortSourceGPIOA,GPIO_PinSource2);

    EXTI_InitStructure.EXTI_Line=EXTI_Line2;
    EXTI_InitStructure.EXTI_Mode=EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger=EXTI_Trigger_Falling;
    EXTI_InitStructure.EXTI_LineCmd=ENABLE;
    EXTI_Init(&EXTI_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannel=EXTI2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority=2;
    NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = TRIG_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(TRIG_PORT, &GPIO_InitStructure);
}

void TIM3_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) //判断是否发生了更新事件
    {
        TIM_Cmd(TIM3, DISABLE);  //关闭定时器
        TIM_SetCounter(TIM3,0);  //清空定时器计数器的值
        GPIO_ResetBits(TRIG_PORT, TRIG_PIN); //关闭超声波发射口

        TIM_ClearITPendingBit(TIM3, TIM_IT_Update);  //清除更新中断标志位
        TIM_ITConfig(TIM3,TIM_IT_Update,DISABLE);   //禁止更新中断
    }
}

void EXTI2_IRQHandler(void)
{
    if(EXTI_GetITStatus(EXTI_Line2) != RESET)  //判断是否为线2发生的中断
    {
        while(GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN)==1);  //等待高电平结束
        u16 dis=TIM_GetCounter(TIM3)*17/100; //计算距离，单位是厘米

        USART_SendData(USART1,dis>>8);
        while(USART_GetFlagStatus(USART1,USART_FLAG_TXE)==RESET);
        USART_SendData(USART1,dis&0xff);
        while(USART_GetFlagStatus(USART1,USART_FLAG_TXE)==RESET);

        EXTI_ClearITPendingBit(EXTI_Line2);  //清除LINE2上的中断标志位
        TIM_SetCounter(TIM3,0);   //计数器清零，为下次测距做准备
        TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE);  //开启定时器更新中断
        TIM_Cmd(TIM3, ENABLE);  //使能定时器3
        GPIO_SetBits(TRIG_PORT, TRIG_PIN); //触发超声波发射口
        delay_us(10);   //延时10us，保证发射口稳定输出
        GPIO_ResetBits(TRIG_PORT, TRIG_PIN);
    }
}

int main(void)
{
    delay_init();
    USART1_Init();
    GPIO_Configuration();
    EXTI_Init();
    TIM3_Int_Init(65535,71);
    while(1);
}

这段代码使用了STM32的GPIO口、定时器和外部中断功能，通过超声波模块的TRIG端口发送一定时间长度的高电平信号来触发超声波发射，并在ECHO端口检测回波信号的高低电平来计算出距离。