stm32两路超声波测速代码

以下是一个使用 STM32 的两路超声波测速的代码示例，其中使用了定时器和中断来实现：

#include "stm32f10x.h"

#define TRIGGER1_PIN GPIO_Pin_0
#define TRIGGER1_PORT GPIOA
#define ECHO1_PIN GPIO_Pin_1
#define ECHO1_PORT GPIOA

#define TRIGGER2_PIN GPIO_Pin_2
#define TRIGGER2_PORT GPIOA
#define ECHO2_PIN GPIO_Pin_3
#define ECHO2_PORT GPIOA

#define SOUND_SPEED 340 // 声速，单位：m/s

volatile uint32_t time1_start = 0;
volatile uint32_t time1_end = 0;
volatile uint32_t time2_start = 0;
volatile uint32_t time2_end = 0;

void delay_us(uint32_t us)
{
    uint32_t count = us * (SystemCoreClock / 1000000);
    while(count--);
}

void EXTI0_IRQHandler()
{
    if(EXTI_GetITStatus(EXTI_Line0) != RESET)
    {
        time1_start = TIM2->CNT;
        EXTI_ClearITPendingBit(EXTI_Line0);
    }
}

void EXTI1_IRQHandler()
{
    if(EXTI_GetITStatus(EXTI_Line1) != RESET)
    {
        time1_end = TIM2->CNT;
        EXTI_ClearITPendingBit(EXTI_Line1);
    }
}

void EXTI2_IRQHandler()
{
    if(EXTI_GetITStatus(EXTI_Line2) != RESET)
    {
        time2_start = TIM2->CNT;
        EXTI_ClearITPendingBit(EXTI_Line2);
    }
}

void EXTI3_IRQHandler()
{
    if(EXTI_GetITStatus(EXTI_Line3) != RESET)
    {
        time2_end = TIM2->CNT;
        EXTI_ClearITPendingBit(EXTI_Line3);
    }
}

int main()
{
    GPIO_InitTypeDef gpio_init_struct;
    EXTI_InitTypeDef exti_init_struct;
    NVIC_InitTypeDef nvic_init_struct;
    TIM_TimeBaseInitTypeDef tim_init_struct;
    
    // 配置引脚
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    gpio_init_struct.GPIO_Mode = GPIO_Mode_Out_PP;
    gpio_init_struct.GPIO_Pin = TRIGGER1_PIN | TRIGGER2_PIN;
    gpio_init_struct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(TRIGGER1_PORT, &gpio_init_struct);
    GPIO_Init(TRIGGER2_PORT, &gpio_init_struct);
    
    gpio_init_struct.GPIO_Mode = GPIO_Mode_IPD;
    gpio_init_struct.GPIO_Pin = ECHO1_PIN | ECHO2_PIN;
    GPIO_Init(ECHO1_PORT, &gpio_init_struct);
    GPIO_Init(ECHO2_PORT, &gpio_init_struct);
    
    // 配置定时器2
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    tim_init_struct.TIM_ClockDivision = TIM_CKD_DIV1;
    tim_init_struct.TIM_CounterMode = TIM_CounterMode_Up;
    tim_init_struct.TIM_Period = 0xFFFF;
    tim_init_struct.TIM_Prescaler = 71;
    TIM_TimeBaseInit(TIM2, &tim_init_struct);
    TIM_Cmd(TIM2, ENABLE);
    
    // 配置外部中断
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource0);
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource1);
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource2);
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource3);
    
    exti_init_struct.EXTI_Line = EXTI_Line0;
    exti_init_struct.EXTI_LineCmd = ENABLE;
    exti_init_struct.EXTI_Mode = EXTI_Mode_Interrupt;
    exti_init_struct.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
    EXTI_Init(&exti_init_struct);
    
    exti_init_struct.EXTI_Line = EXTI_Line1;
    EXTI_Init(&exti_init_struct);
    
    exti_init_struct.EXTI_Line = EXTI_Line2;
    EXTI_Init(&exti_init_struct);
    
    exti_init_struct.EXTI_Line = EXTI_Line3;
    EXTI_Init(&exti_init_struct);
    
    nvic_init_struct.NVIC_IRQChannel = EXTI0_IRQn;
    nvic_init_struct.NVIC_IRQChannelCmd = ENABLE;
    nvic_init_struct.NVIC_IRQChannelPreemptionPriority = 0;
    nvic_init_struct.NVIC_IRQChannelSubPriority = 0;
    NVIC_Init(&nvic_init_struct);
    
    nvic_init_struct.NVIC_IRQChannel = EXTI1_IRQn;
    NVIC_Init(&nvic_init_struct);
    
    nvic_init_struct.NVIC_IRQChannel = EXTI2_IRQn;
    NVIC_Init(&nvic_init_struct);
    
    nvic_init_struct.NVIC_IRQChannel = EXTI3_IRQn;
    NVIC_Init(&nvic_init_struct);
    
    // 循环测量距离
    while(1)
    {
        // 触发超声波测距 1
        GPIO_SetBits(TRIGGER1_PORT, TRIGGER1_PIN);
        delay_us(10);
        GPIO_ResetBits(TRIGGER1_PORT, TRIGGER1_PIN);
        
        // 等待测距完成
        while(GPIO_ReadInputDataBit(ECHO1_PORT, ECHO1_PIN) == RESET);
        
        // 开始测距
        while(GPIO_ReadInputDataBit(ECHO1_PORT, ECHO1_PIN) == SET);
        while(GPIO_ReadInputDataBit(ECHO1_PORT, ECHO1_PIN) == RESET);
        while(GPIO_ReadInputDataBit(ECHO1_PORT, ECHO1_PIN) == SET);
        
        uint32_t time1 = time1_end - time1_start;
        float distance1 = time1 * SOUND_SPEED / 2.0f / 1000000.0f; // 测距公式：distance = time * 声速 / 2
        
        // 触发超声波测距 2
        GPIO_SetBits(TRIGGER2_PORT, TRIGGER2_PIN);
        delay_us(10);
        GPIO_ResetBits(TRIGGER2_PORT, TRIGGER2_PIN);
        
        // 等待测距完成
        while(GPIO_ReadInputDataBit(ECHO2_PORT, ECHO2_PIN) == RESET);
        
        // 开始测距
        while(GPIO_ReadInputDataBit(ECHO2_PORT, ECHO2_PIN) == SET);
        while(GPIO_ReadInputDataBit(ECHO2_PORT, ECHO2_PIN) == RESET);
        while(GPIO_ReadInputDataBit(ECHO2_PORT, ECHO2_PIN) == SET);
        
        uint32_t time2 = time2_end - time2_start;
        float distance2 = time2 * SOUND_SPEED / 2.0f / 1000000.0f; // 测距公式：distance = time * 声速 / 2
        
        // 打印结果
        printf("Distance1: %.2f cm\r\n", distance1 * 100);
        printf("Distance2: %.2f cm\r\n", distance2 * 100);
        
        // 延时一段时间
        delay_us(500000);
    }
}

需要注意的是，这是一个简化的代码示例，实际应用中还需要根据具体情况进行优化和修改。