蓝桥杯电子类超声波程序

超声波测距一般需要用到超声波模块和单片机，以下是一个基于STM32的超声波测距程序，可以参考：

#include "stm32f10x.h"

#define TRIG_PIN GPIO_Pin_0
#define TRIG_PORT GPIOB
#define ECHO_PIN GPIO_Pin_1
#define ECHO_PORT GPIOB

// 定义计数器的最大值和最小值
#define MAX_CNT 50000
#define MIN_CNT 3

// 定义超声波模块的工作频率
#define FREQ 40

// 定义超声波测距的时间参数
#define TIME1 10
#define TIME2 5800

// 定义超声波测距的公式
#define DISTANCE (340 * TIME1 * TIME2 / (2 * FREQ * 1000000))

uint16_t time_cnt;

void delay_us(uint16_t us) {
    TIM2->ARR = us;  // 设置计数器的自动重载值
    TIM2->CNT = 0;  // 清零计数器的计数值
    TIM2->SR &= ~TIM_SR_UIF;  // 清除定时器的溢出标志
    TIM2->CR1 |= TIM_CR1_CEN;  // 使能计数器
    while ((TIM2->SR & TIM_SR_UIF) == 0);  // 等待计数器溢出
    TIM2->CR1 &= ~TIM_CR1_CEN;  // 关闭计数器
}

void TIM3_IRQHandler() {
    if (TIM_GetITStatus(TIM3, TIM_IT_CC1) != RESET) {
        if (GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN)) {
            // 如果IO口为高电平，计数器开始计数
            TIM_SetCounter(TIM2, 0);
        } else {
            // 如果IO口为低电平，计数器停止计数
            time_cnt = TIM_GetCounter(TIM2);
        }
        TIM_ClearITPendingBit(TIM3, TIM_IT_CC1);
    }
}

int main() {
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
    TIM_ICInitTypeDef TIM_ICInitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
    
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);  // 使能GPIOB的时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);  // 使能TIM3的时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);  // 使能TIM2的时钟
    
    // 配置PB0和PB1的GPIO口
    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_IPD;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(ECHO_PORT, &GPIO_InitStructure);
    
    // 配置TIM3的时间基准
    TIM_TimeBaseInitStructure.TIM_Period = 65535;
    TIM_TimeBaseInitStructure.TIM_Prescaler = 72 - 1;
    TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseInitStructure);
    
    // 配置TIM3的输入捕获通道
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
    TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
    TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
    TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
    TIM_ICInitStructure.TIM_ICFilter = 0x0F;
    TIM_ICInit(TIM3, &TIM_ICInitStructure);
    
    // 配置TIM2的时间基准
    TIM_TimeBaseInitStructure.TIM_Period = MAX_CNT;
    TIM_TimeBaseInitStructure.TIM_Prescaler = 72 - 1;
    TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);
    
    // 配置TIM3的中断
    NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
    
    while (1) {
        GPIO_SetBits(TRIG_PORT, TRIG_PIN);  // 发送超声波信号
        delay_us(10);
        GPIO_ResetBits(TRIG_PORT, TRIG_PIN);
        
        TIM_SetCounter(TIM2, 0);  // 清零计数器的计数值
        
        TIM_ClearITPendingBit(TIM3, TIM_IT_CC1);  // 清除TIM3的中断标志
        TIM_ITConfig(TIM3, TIM_IT_CC1, ENABLE);  // 使能TIM3的中断
        while (TIM_GetFlagStatus(TIM3, TIM_FLAG_CC1) == RESET);  // 等待输入捕获中断
        
        TIM_ITConfig(TIM3, TIM_IT_CC1, DISABLE);  // 关闭TIM3的中断
        
        if (time_cnt < MIN_CNT || time_cnt > MAX_CNT) {
            // 如果计数值不在范围内，说明距离太远或太近
            continue;
        }
        
        printf("Distance: %d cm\n", DISTANCE);
        
        delay_us(500000);  // 延时500ms
    }
}

需要注意的是，这是一个简单的程序，仅供参考。实际应用中，需要根据具体的超声波模块和单片机进行调整。