stm32超声波测距代码

以下是一个简单的 stm32 超声波测距代码：

#include "stm32f10x.h"

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

void delay_us(uint32_t nus)
{
    uint32_t i;
    for (i = 0; i < nus * 8; i++);
}

void delay_ms(uint32_t nms)
{
    uint32_t i;
    for (i = 0; i < nms * 8000; i++);
}

void send_trigger_pulse(void)
{
    GPIO_WriteBit(TRIG_PORT, TRIG_PIN, Bit_SET);
    delay_us(10);
    GPIO_WriteBit(TRIG_PORT, TRIG_PIN, Bit_RESET);
}

float measure_distance(void)
{
    uint32_t start_tick = 0, end_tick = 0;
    float distance = 0;
    while (GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN) == RESET);
    start_tick = TIM_GetCounter(TIM2);
    while (GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN) == SET);
    end_tick = TIM_GetCounter(TIM2);
    distance = (float)(end_tick - start_tick) * 1.7 / 100.0;
    return distance;
}

int main(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

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

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

    TIM_TimeBaseInitStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseInitStructure.TIM_Prescaler = 71;
    TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);
    TIM_Cmd(TIM2, ENABLE);

    while (1)
    {
        send_trigger_pulse();
        delay_ms(50);
        float distance = measure_distance();
        // Do something with the measured distance
    }
}

这个代码使用 TIM2 来计算超声波的回波时间，通过计算回波时间来计算距离。TRIG_PIN 是超声波发射器的引脚，ECHO_PIN 是超声波接收器的引脚。在 main 函数中，我们使用一个死循环来循环测量距离。你可以根据实际情况修改 delay_ms 的参数来控制测量频率。