STM32定时器编码器模式计算减速电机AB相脉冲个数，通过 AB相脉冲的上升沿和下降沿触发，然后计数器加一，那么如果检测到一个周期，有AB两相，两个上升沿两个下降沿的话，计数器就会四个 加一 。

#ifndef __TIMER_H

#define __TIMER_H

#include "sys.h"

void TIM3_Int_Init(u16 arr,u16 psc);

void TIM8_Encoder_Init(u16 arr,u16 psc) ;

void Frequent(void) ;

#endif

#include "timer.h"

#include "led.h"

#include "delay.h"

#include "lcd.h"

#include "usart.h"

#define PI 3.14

//#define ar 719

//#define ps 99

#define TIM 90.0

//通用定时器3中断初始化

//这里时钟选择为APB1的2倍，而APB1为36M

//arr：自动重装值。

//psc：时钟预分频数

//这里使用的是定时器3!

u16 i =1,EncVal ,num = 0 ;

void TIM3_Int_Init(u16 arr,u16 psc)

{

  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //时钟使能

//定时器TIM3初始化

TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值

TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值

TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //设置时钟分割:TDTS = Tck_tim

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上计数模式

TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根据指定的参数初始化TIMx的时间基数单位

 // TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Trigger);//选择TIMx从模式

TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE ); //使能指定的TIM3中断,允许更新中断

//中断优先级NVIC设置

NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;  //TIM3中断

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  //先占优先级3级

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;  //从优先级3级

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能

NVIC_Init(&NVIC_InitStructure);  //初始化NVIC寄存器

  //TIM3_Encoder_Write(65416) ;

TIM_Cmd(TIM3, ENABLE);  //使能TIMx  

}

void TIM2_Encoder_Init(u16 arr,u16 psc)

{

  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

NVIC_InitTypeDef NVIC_InitStructure;

TIM_ICInitTypeDef TIM_ICInitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); //时钟使能

//定时器TIM2初始化

TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值

TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值

TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //设置时钟分割:TDTS = Tck_tim

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上计数模式

TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //根据指定的参数初始化TIMx的时间基数单位

//TIM_SetCounter(TIM3, 0xFF88);//设置TIMx自动重装载寄存器值

TIM_EncoderInterfaceConfig(TIM2, TIM_EncoderMode_TI12,

                                TIM_ICPolarity_Falling, TIM_ICPolarity_Falling);

TIM_ICStructInit(&TIM_ICInitStructure);

TIM_ICInitStructure.TIM_ICFilter = 6;

//TIM_ICInitStructure.TIM_ICPolarity = EXTI_Trigger_Rising_Falling; //上升沿捕获

//TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //配置输入分频,不分频 

TIM_ICInit(TIM2, &TIM_ICInitStructure);

  //TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Trigger);//选择TIMx从模式

  TIM_ClearFlag(TIM2, TIM_FLAG_Update);

TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE ); //使能指定的TIM3中断,允许更新中断

  //TIM2->CNT = 120;

//中断优先级NVIC设置

NVIC_InitStructure.NVIC_IRQChannel = TIM_Channel_1|TIM_Channel_2;  //TIM3中断

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  //先占优先级3级

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;  //从优先级3级

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能

  NVIC_Init(&NVIC_InitStructure);  //初始化NVIC寄存器

  //TIM3_Encoder_Write(65416) ;

TIM_Cmd(TIM2, ENABLE);  //使能TIMx  

}

extern void coordinate(void) ;

u8 speed[12] ;

//extern int ar ,ps ;

  double fre ;

  int p;  

 double sin(double) ;

double  GetTrigVal(u16 y)

{ 

double t,n;

n = (double)(y/90.0) *2*PI ;

  t = sin(n)*100 ;

  return  t;

}

void Frequent(void)

{

   //fre = 1000/((int)TIM /((ar+1)*(ps+1)/72)) ;

fre = 16.0 /5.0;

}

//定时器3中断服务程序

void TIM3_IRQHandler(void)   //TIM3中断

{

if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)  //检查TIM3更新中断发生与否

{

TIM_ClearITPendingBit(TIM3, TIM_IT_Update  );  //清除TIMx更新中断标志 

    TIM2->SMCR ^= 0x8000  ;

EncVal = TIM_GetCounter(TIM2);

if(EncVal>=240)

{

         EncVal = 240; 

      }

  LCD_DrawPoint(i, 5+EncVal);

  if(i==320)

  {  

    i =0;

        LCD_Clear(WHITE);

    coordinate()  ; //横坐标

             //delay_ms(50);

  }

i++ ; 

TIM2->CNT = 240; 

   Frequent() ;

     //fre = 1000/(90 /(720*100/72)) ;

  //sprintf((char*)speed,"speed : %d ",EncVal );//将LCD ID打印到lcd_id数组。

//sprintf((char*)lcd_id,"LCD ID:X",lcddev.id);

//LCD_ShowString(200,200,200,16,16,"EncVal");

LCD_ShowxNum(250,200,EncVal,5,16,0);

printf("%d\r\n",EncVal) ;

    TIM_SetAutoreload(TIM1, 0xFF88);//设置TIMx自动重装载寄存器值

  }

}