一、编码器接口介绍

1.编码器接口

        编码器接口可接收增量（正交）编码器的信号，根据编码器旋转产生的正交信号脉冲，自动控制CNT自增或自减，从而指示编码器的位置、旋转方向和旋转速度；每个高级定时器和通用定时器都拥有1个编码器接口；两个输入引脚借用了输入捕获的通道1和通道2

正交编码器：

编码器接口的基本编程结构：

编码器接口工作逻辑

作用过程：

反向计数方式：

二、编码器测速

配置：

#include "stm32f10x.h"                  // Device header

void Encoder_Init(void)
{
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
	
	GPIO_InitTypeDef GPIO_InitStructure;
 	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //设定为复用推挽输出
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_7 ;
 	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	//2.TIM初始化
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);
	
	//（1）PWM频率:Freq = CK_PSC / (PSC +1) / (ARR +1)
    //（2）PWM占空比:Duty=CCR/(ARR+1)
	//（3）PWM分辨率:Reso=1/(ARR+1)

	
	TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
	TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1; //用于采样电路的分频
	TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;//定时器计数方式:上、下、中央对其
	TIM_TimeBaseInitStructure.TIM_Period = 65536-1;//ARR
	TIM_TimeBaseInitStructure.TIM_Prescaler = 1-1;//PSC   
	TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;//重复计数器,只在高级计数器中使用
	TIM_TimeBaseInit(TIM3,&TIM_TimeBaseInitStructure);
	
	//3.初始化输入捕获单元
	TIM_ICInitTypeDef TIM_ICInitStructure;
	
	TIM_ICStructInit(&TIM_ICInitStructure);
	TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;//通道一
	TIM_ICInitStructure.TIM_ICFilter = 0xF;
	TIM_ICInit(TIM3,&TIM_ICInitStructure);
	
	TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;//通道二
	TIM_ICInitStructure.TIM_ICFilter = 0xF;
	TIM_ICInit(TIM3,&TIM_ICInitStructure);
	
	TIM_EncoderInterfaceConfig(TIM3,TIM_EncoderMode_TI12,TIM_ICPolarity_Rising,TIM_ICPolarity_Rising );
	
	TIM_Cmd(TIM3,ENABLE);
}

int16_t Get_Encoder(void)
{
	int16_t Temp;
	Temp = TIM_GetCounter(TIM3);
	TIM_SetCounter(TIM3,0);
	
	return Temp;
}

一秒定时器中断：

#include "stm32f10x.h"                  // Device header

void Timer_Init(void)
{
	//TIM初始化
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
	
	TIM_InternalClockConfig(TIM2);
	
	TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
	TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1; //用于采样电路的分频
	TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;//定时器计数方式:上、下、中央对其
	TIM_TimeBaseInitStructure.TIM_Period = 10000-1;//ARR
	TIM_TimeBaseInitStructure.TIM_Prescaler = 7200-1;//PSC    计时=(ARR-1)*(PSC-1)/主频=1S
	TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;//重复计数器,只在高级计数器中使用
	TIM_TimeBaseInit(TIM2,&TIM_TimeBaseInitStructure);
	
	TIM_ClearFlag(TIM2,TIM_FLAG_Update);//手动清除中断标志位，避免一开始就进入中断的问题
	
	TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
	
	
	//NVIC初始化
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	
	NVIC_InitTypeDef NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
	NVIC_Init(&NVIC_InitStructure);
	
	TIM_Cmd(TIM2, ENABLE);
}

主函数：

#include "stm32f10x.h"                  // Device header
#include "OLED.h"
#include "Matrix_Key.h"
#include "LED.h"
#include "Delay.h"
#include "Timer.h"
#include "Encoder.h"

int16_t Speed;


int main(void)
{
	Encoder_Init();
	Timer_Init();
	OLED_Init();
	
	OLED_ShowString(1,1,"Speed:");
	
	while(1)
	{
		OLED_ShowSignedNum(1,7,Speed,5);//编码器测量位置
	}
}


void TIM2_IRQHandler(void)
{
	if(TIM_GetITStatus(TIM2,TIM_IT_Update)==SET)
	{
		Speed = Get_Encoder();
		TIM_ClearITPendingBit(TIM2,TIM_IT_Update);
	}
	
}

测速原理：在一秒的定时器中断内，对脉冲数Temp进行计数，即为速度

若要完成编码器测速，还需要关注减速比、4倍频、转换在一分钟内测速等，且由于电机转速较快，需要减少中断时间保证测速的准确性