江科大STM32(3)：定时器（4）定时器的编码器接口

1.编码器接口简介

Encoder Interface 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（CH1和CH2引脚）

2.编码器接口基本结构

2.1 工作模式

2.2 编码器接口基本结构

初始化步骤

第一步，RCC开启时钟，开启GPIO和定时器的时钟。

第二步，配置GPIO，6-8中把PA6和PA7配置为输入模式。

第三步，配置时基单元，这里的预分频器一般选择不分配，自动重装，一般给最大65535，只需要个CNT执行计数就行了。

第四步，配置输入捕获单元，这里输入捕获单元只有滤波器和极性两个参数有用。

第五步，配置编码器接口模式，调用库函数。

最后，调用TIM_Cmd，启动定时器。

3.实操

3.1 库函数

    TIM_ICInitTypeDef TIM_ICInitStructure;        //定义结构体变量
    TIM_ICStructInit(&TIM_ICInitStructure);          //给结构体赋一个初始值
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
    TIM_ICInitStructure.TIM_ICFilter = 0xF;
    //TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
    TIM_ICInit(TIM3, &TIM_ICInitStructure);          //调用ICInit配置电路，写入了硬件，之后换个值继续写入
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
    TIM_ICInitStructure.TIM_ICFilter = 0xF;
    //TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
    TIM_ICInit(TIM3, &TIM_ICInitStructure);
 
    TIM_EncoderInterfaceConfig(TIM3, TIM_EncoderMode_TI12, TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);//第三 第四与上面相同

//定时器编码器接口配置
void TIM_EncoderInterfaceConfig(TIM_TypeDef* TIMx, uint16_t TIM_EncoderMode,uint16_t TIM_IC1Polarity, uint16_t TIM_IC2Polarity);

3.2 编码器接口测速

3.2.1 实验现象

3.2.2 代码

Encoder.c

#include "stm32f10x.h"                  // Device header

void Encoder_Init(void)
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
        
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
    TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInitStructure.TIM_Period = 65536 - 1;        //ARR
    TIM_TimeBaseInitStructure.TIM_Prescaler = 1 - 1;        //PSC
    TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseInitStructure);
    
    TIM_ICInitTypeDef TIM_ICInitStructure;//配置输入捕获单元
    TIM_ICStructInit(&TIM_ICInitStructure);
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
    TIM_ICInitStructure.TIM_ICFilter = 0xF;
    TIM_ICInit(TIM3, &TIM_ICInitStructure);
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
    TIM_ICInitStructure.TIM_ICFilter = 0xF;
    TIM_ICInit(TIM3, &TIM_ICInitStructure);
    
    TIM_EncoderInterfaceConfig(TIM3, TIM_EncoderMode_TI12, TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);//配置编码器接口模式
    
    TIM_Cmd(TIM3, ENABLE);
}

int16_t Encoder_Get(void)
{
    int16_t Temp;
    Temp = TIM_GetCounter(TIM3);//获取当前计数器的值
    TIM_SetCounter(TIM3, 0);//给计数器写入一个值
    return Temp;
}

main.c

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

int16_t Speed;

int main(void)
{
    OLED_Init();
    Timer_Init();
    Encoder_Init();
    
    OLED_ShowString(1, 1, "Speed:");
    
    while (1)
    {
        OLED_ShowSignedNum(1, 7, Speed, 5);
    }
}

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

Timer.c

#include "stm32f10x.h"                  // Device header

void Timer_Init(void)
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    
    TIM_InternalClockConfig(TIM2);
    
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
    TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInitStructure.TIM_Period = 10000 - 1;
    TIM_TimeBaseInitStructure.TIM_Prescaler = 7200 - 1;
    TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);
    
    TIM_ClearFlag(TIM2, TIM_FLAG_Update);
    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
    
    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);
}

/*
void TIM2_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM2, TIM_IT_Update) == SET)
    {
        
        TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
    }
}
*/