STM32如何利用编码器测距代码

编码器是一种常用的测距设备，STM32可以通过读取编码器的信号来测量物体的距离。下面是一个基本的编码器测距代码示例：

#include "stm32f10x.h"
#include "stdio.h"

#define ENCODER_TIM_PERIOD 65535   //编码器定时器的最大计数值

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_ICInitTypeDef TIM_ICInitStructure;

int main(void)
{
    uint16_t EncoderVal = 0;
    float Distance = 0;
    float Resolution = 0.5;   //编码器分辨率，单位mm

    //使能GPIOA和TIM2时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO | RCC_APB2Periph_TIM1, ENABLE);

    //初始化GPIOA的PA8和PA9引脚
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    //初始化TIM1
    TIM_TimeBaseStructure.TIM_Period = ENCODER_TIM_PERIOD;
    TIM_TimeBaseStructure.TIM_Prescaler = 0;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

    //初始化TIM1通道1和通道2为编码器输入模式
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1 | TIM_Channel_2;
    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(TIM1, &TIM_ICInitStructure);

    //启动TIM1定时器
    TIM_Cmd(TIM1, ENABLE);

    while(1)
    {
        //读取编码器计数器的值
        EncoderVal = TIM1->CNT;

        //计算距离
        Distance = EncoderVal * Resolution;

        printf("Distance: %.2f mm\r\n", Distance);

        //延时一段时间
        Delay(100);
    }
}

//延时函数
void Delay(uint32_t nCount)
{
    for(; nCount != 0; nCount--);
}

以上代码中，使用了STM32的TIM1定时器作为编码器输入捕获的计数器，通过读取计数器的值来计算距离。具体实现中，需要将TIM1的通道1和通道2配置为编码器输入模式，然后在主函数中不断读取TIM1计数器的值，并计算距离。