stm32超声波测距代码

以下是一个简单的STM32超声波测距代码，具体实现可能与你使用的超声波模块有关，需要根据模块的特性进行调整。

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

#define TRIG_PIN GPIO_Pin_0
#define TRIG_PORT GPIOA

#define ECHO_PIN GPIO_Pin_1
#define ECHO_PORT GPIOA

void TIM2_Init(void);
void TIM2_IRQHandler(void);

volatile uint32_t distance = 0;

int main(void)
{
    // 初始化GPIO口
    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);

    GPIO_InitStructure.GPIO_Pin = ECHO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(ECHO_PORT, &GPIO_InitStructure);

    // 初始化定时器
    TIM2_Init();

    while(1)
    {
        // 触发超声波模块
        GPIO_ResetBits(TRIG_PORT, TRIG_PIN);
        delay_us(2);
        GPIO_SetBits(TRIG_PORT, TRIG_PIN);
        delay_us(10);
        GPIO_ResetBits(TRIG_PORT, TRIG_PIN);

        // 等待超声波返回
        while(GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN) == RESET);

        // 记录超声波返回时的定时器计数值
        TIM_SetCounter(TIM2, 0);
        while(GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN) == SET);

        // 计算距离
        uint32_t cnt = TIM_GetCounter(TIM2);
        distance = cnt * 10 / 58; // 根据超声波模块特性计算距离
    }
}

void TIM2_Init(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = (SystemCoreClock / 1000000) - 1;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
    TIM_Cmd(TIM2, ENABLE);

    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

void TIM2_IRQHandler(void)
{
    if(TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
    {
        TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
    }
}

需要注意的是，这里用到了一个延时函数`delay_us()`，需要根据你的实际情况进行实现。此外，根据超声波模块的特性，需要根据实际情况调整计算距离的公式。