Stm32对光电编码器M法测速的代码

下面是一份基于STM32的光电编码器M法测速的代码，供参考：

#include "stm32f10x.h"

#define PI 3.1415926535f
#define ENCODER_PPR 600.0f // 光电编码器的脉冲数（每转）

volatile uint16_t encoder_count = 0;
volatile uint16_t last_encoder_count = 0;
volatile uint16_t encoder_speed = 0;

void TIM3_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)
    {
        encoder_count = TIM_GetCounter(TIM2);
        TIM_SetCounter(TIM2, 0);

        if (encoder_count > last_encoder_count)
        {
            encoder_speed = (encoder_count - last_encoder_count) * 7200 / ENCODER_PPR; // 计算转速（单位：rpm）
        }
        else
        {
            encoder_speed = (last_encoder_count - encoder_count) * 7200 / ENCODER_PPR;
        }

        last_encoder_count = encoder_count;

        TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
    }
}

int main(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    // 初始化TIM2作为计数器
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = 0;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
    TIM_Cmd(TIM2, ENABLE);

    // 初始化TIM3作为计算转速的定时器
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
    TIM_TimeBaseStructure.TIM_Period = 1000; // 定时器周期为1ms
    TIM_TimeBaseStructure.TIM_Prescaler = 7200 - 1; // 定时器时钟源为72MHz，预分频7200，计数时钟为10kHz
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
    TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);
    TIM_Cmd(TIM3, ENABLE);

    // 配置中断优先级
    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)
    {
        // do something
    }
}

该代码中使用了STM32的TIM2和TIM3定时器，其中TIM2作为光电编码器的计数器，每接收到一个脉冲就加1，而TIM3作为计算转速的定时器，每隔1ms就计算一次转速并保存到全局变量encoder_speed中。在TIM3的中断服务函数中，通过计算TIM2的计数值来得到编码器转动的脉冲数，从而计算出转速。需要注意的是，在计算转速时需要将脉冲数转换为转速，这里使用了PPR和7200来进行转换。