stm32编码器测速程序

以下是一个基本的STM32编码器测速程序，使用TIM2模块来捕获编码器信号并计算速度：

#include "stm32f4xx.h"

#define ENCODER_PPR 1000 //编码器每圈脉冲数
#define TIMER_TICKS_PER_SECOND 84000000 //定时器时钟频率

volatile uint32_t timer_value = 0; //定时器计数器值
volatile int32_t encoder_count = 0; //编码器计数器值
volatile int32_t last_encoder_count = 0; //上一次编码器计数器值

int main(void)
{
  //初始化GPIO和定时器
  GPIO_InitTypeDef GPIO_InitStructure;
  TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
  TIM_ICInitTypeDef TIM_ICInitStructure;

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_PinAFConfig(GPIOA, GPIO_PinSource0, GPIO_AF_TIM2);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource1, GPIO_AF_TIM2);

  TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
  TIM_TimeBaseStructure.TIM_Prescaler = 0;
  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

  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 = 0;
  TIM_ICInit(TIM2, &TIM_ICInitStructure);

  TIM_ICInitStructure.TIM_Channel = 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 = 0;
  TIM_ICInit(TIM2, &TIM_ICInitStructure);

  TIM_Cmd(TIM2, ENABLE);

  //启用定时器中断
  NVIC_InitTypeDef NVIC_InitStructure;
  NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
  TIM_ITConfig(TIM2, TIM_IT_CC1, ENABLE);
  TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE);

  while (1)
  {
    //计算速度
    int32_t delta_encoder_count = encoder_count - last_encoder_count;
    float rpm = (float)delta_encoder_count * 60.0 * (float)TIMER_TICKS_PER_SECOND / (float)ENCODER_PPR / (float)timer_value;
    last_encoder_count = encoder_count;
    timer_value = 0;
  }
}

void TIM2_IRQHandler(void)
{
  if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
  {
    TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
    timer_value += 0x10000;
  }
  else if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET)
  {
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC1);
    encoder_count++;
  }
  else if (TIM_GetITStatus(TIM2, TIM_IT_CC2) != RESET)
  {
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
    encoder_count--;
  }
}

在这个程序中，TIM2被配置为边沿捕获模式，通过GPIOA0和GPIOA1输入编码器信号。定时器每次计数都会触发一个中断，并增加定时器计数器的值。当编码器信号发生上升沿或下降沿时，对应的中断也会触发，并增加编码器计数器的值。在主循环中，程序通过定时器计数器和编码器计数器的变化计算速度，并更新上一次编码器计数器的值。