EC11编码器编码使用

前要

关于EC11编码器的了解可以参考两篇文章，比较详细，在此就不多介绍了：

• 一篇文章带你了解——EC11编码器（关于硬件、原理图、上下拉等都有讲）
• 认识EC11旋转编码器&编写驱动程序

原理

脉冲与定位

• 15脉冲/30定位：每拨动一格，两个电平都相继翻转，是半个脉冲；再拨动一格，电平再相继翻转，也是半个脉冲；两个半脉冲形成一个完整脉冲。静止状态下，两个电平相同，都为高或低
• 20脉冲/20定位：每拨动一格，形成一个完整脉冲
  对应下图如下：
  
  示波器抓取部分波形：
  
    (note: 两个脉冲跳变的间隔约为几十ms)

功能

通过2个pin负责编码器的波形检测，顺时针与逆时针波形不同

硬件设计

IO外部上拉与无上拉

编程

硬件条件：

• MCU:    stm32f407
• 编码器类型： EC11-15脉冲/30定位
• 连接：    IO外部无上拉，设置MCU GPIO的内部上拉

下面使用两种方法来对编码器进行计数和使用。

轮询模式

直接就上代码了，随意两个GPIO

//GPIO初始化
void MX_GPIO_Init(void)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin : PB6 */
  GPIO_InitStruct.Pin = GPIO_PIN_6;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /*Configure GPIO pin : PB7 */
  GPIO_InitStruct.Pin = GPIO_PIN_7;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

}

//判断检测
int main(void)
{
  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USART1_UART_Init();
  /* USER CODE BEGIN 2 */
  // exit_init();
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  uint32_t count = 0;
  uint32_t wait_t = 0;
  bool encoder_switch = 0;
  uint8_t encoder_a_pre = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_6);
  // uint8_t encoder_b_pre = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7);
  int32_t steps = 0;
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
    uint32_t t = HAL_GetTick();

    uint8_t encoder_a = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_6);
    uint8_t encoder_b = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7);

    if (encoder_a_pre != encoder_a && !encoder_switch) {
      wait_t = HAL_GetTick();
      encoder_switch = true;
    }
    if (encoder_switch && ((t - wait_t) >= 2 )) {
      //a 0->1, b 0 Clockwise; b 1 AntiClockwise
      if (encoder_a == 1) {
        if (encoder_b == 0) {
          steps++;
        } else {
          steps--;
        }
      }
      //a 1->0, b 1 Clockwise; b 0 AntiClockwise 
      else {
        if (encoder_b == 1) {
          steps++;
        } else {
          steps--;
        }
      }
      encoder_switch = false;
      encoder_a_pre = encoder_a;
      printf("%d\r\n", steps);
    }
 
  }
  /* USER CODE END 3 */
}

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注意点：编码器电平发生变化时可能存在噪声，类似按键一样需要增加延时防抖，并且考虑到在系统中少加入延时死等这些不友善的代码，所以代码中有如上处理。

定时器Encoder模式

stm32中定时器有自带Encoder的功能，所以可以借助定时器的这个特性来实现我们的需求。
直接撸代码，GPIO必须使用复用功能有定时器的pin。

//定时器及IO初始化
TIM_HandleTypeDef htim4;

/* TIM4 init function */
void MX_TIM4_Init(void)
{

  /* USER CODE BEGIN TIM4_Init 0 */

  /* USER CODE END TIM4_Init 0 */

  TIM_Encoder_InitTypeDef sConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};

  /* USER CODE BEGIN TIM4_Init 1 */

  /* USER CODE END TIM4_Init 1 */
  htim4.Instance = TIM4;
  htim4.Init.Prescaler = 0;
  htim4.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim4.Init.Period = 65535;
  htim4.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim4.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
  sConfig.EncoderMode = TIM_ENCODERMODE_TI1;
  sConfig.IC1Polarity = TIM_ICPOLARITY_FALLING;
  sConfig.IC1Selection = TIM_ICSELECTION_DIRECTTI;
  sConfig.IC1Prescaler = TIM_ICPSC_DIV1;
  sConfig.IC1Filter = 3;
  sConfig.IC2Polarity = TIM_ICPOLARITY_FALLING;
  sConfig.IC2Selection = TIM_ICSELECTION_DIRECTTI;
  sConfig.IC2Prescaler = TIM_ICPSC_DIV1;
  sConfig.IC2Filter = 3;
  if (HAL_TIM_Encoder_Init(&htim4, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim4, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM4_Init 2 */
  HAL_TIM_Encoder_Start(&htim4, TIM_CHANNEL_ALL);
  /* USER CODE END TIM4_Init 2 */

}

void HAL_TIM_Encoder_MspInit(TIM_HandleTypeDef* tim_encoderHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(tim_encoderHandle->Instance==TIM4)
  {
  /* USER CODE BEGIN TIM4_MspInit 0 */

  /* USER CODE END TIM4_MspInit 0 */
    /* TIM4 clock enable */
    __HAL_RCC_TIM4_CLK_ENABLE();

    __HAL_RCC_GPIOB_CLK_ENABLE();
    /**TIM4 GPIO Configuration
    PB6     ------> TIM4_CH1
    PB7     ------> TIM4_CH2
    */
    GPIO_InitStruct.Pin = GPIO_PIN_6|GPIO_PIN_7;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF2_TIM4;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /* USER CODE BEGIN TIM4_MspInit 1 */

  /* USER CODE END TIM4_MspInit 1 */
  }
}

//获取编码器变化
int main(void)
{
  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USART1_UART_Init();
  /* USER CODE BEGIN 2 */
  // exit_init();
  MX_TIM4_Init();
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  int32_t Enc_Count_pre =  __HAL_TIM_GET_COUNTER(&htim4);
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
    int32_t Enc_Count =  __HAL_TIM_GET_COUNTER(&htim4);
    if (Enc_Count != Enc_Count_pre) {
      printf("%d\r\n", Enc_Count);
      Enc_Count_pre = Enc_Count;
    }
    
  }
  /* USER CODE END 3 */
}
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结束语

此两种方式已做测试，稳得一批，如果细节问题可沟通。

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— 2021.10.22-21:45于广东深圳