text: // Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #pragma once
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #define PCNT_PIN_NOT_USED     (-1)  /*!< When selected for a pin, this pin will not be used */
  
  /**
   * @brief PCNT port number, the max port number is (PCNT_PORT_MAX - 1).
   */
  typedef enum {
      PCNT_PORT_0 = 0,                 /*!< PCNT port 0 */
      PCNT_PORT_MAX,                   /*!< PCNT port max */
  } pcnt_port_t;
  
  /**
   * @brief Selection of all available PCNT units
   */
  typedef enum {
      PCNT_UNIT_0 = 0,                 /*!< PCNT unit 0 */
      PCNT_UNIT_1 = 1,                 /*!< PCNT unit 1 */
      PCNT_UNIT_2 = 2,                 /*!< PCNT unit 2 */
      PCNT_UNIT_3 = 3,                 /*!< PCNT unit 3 */
  #if SOC_PCNT_UNIT_NUM > 4
      PCNT_UNIT_4 = 4,                 /*!< PCNT unit 4 */
      PCNT_UNIT_5 = 5,                 /*!< PCNT unit 5 */
      PCNT_UNIT_6 = 6,                 /*!< PCNT unit 6 */
      PCNT_UNIT_7 = 7,                 /*!< PCNT unit 7 */
  #endif
      PCNT_UNIT_MAX,
  } pcnt_unit_t; 
  
  /**
   * @brief Selection of available modes that determine the counter's action depending on the state of the control signal's input GPIO
   * @note  Configuration covers two actions, one for high, and one for low level on the control input
   */
  typedef enum {
      PCNT_MODE_KEEP = 0,             /*!< Control mode: won't change counter mode*/
      PCNT_MODE_REVERSE = 1,          /*!< Control mode: invert counter mode(increase -> decrease, decrease -> increase) */
      PCNT_MODE_DISABLE = 2,          /*!< Control mode: Inhibit counter(counter value will not change in this condition) */
      PCNT_MODE_MAX
  } pcnt_ctrl_mode_t;
  
  /**
   * @brief Selection of available modes that determine the counter's action on the edge of the pulse signal's input GPIO
   * @note  Configuration covers two actions, one for positive, and one for negative edge on the pulse input
   */
  typedef enum {
      PCNT_COUNT_DIS = 0,            /*!< Counter mode: Inhibit counter(counter value will not change in this condition) */
      PCNT_COUNT_INC = 1,            /*!< Counter mode: Increase counter value */
      PCNT_COUNT_DEC = 2,            /*!< Counter mode: Decrease counter value */
      PCNT_COUNT_MAX
  } pcnt_count_mode_t;
  
  /**
   * @brief Selection of channels available for a single PCNT unit
   */
  typedef enum {
      PCNT_CHANNEL_0 = 0x00,           /*!< PCNT channel 0 */
      PCNT_CHANNEL_1 = 0x01,           /*!< PCNT channel 1 */
      PCNT_CHANNEL_MAX,
  } pcnt_channel_t;
  
  /**
   * @brief Selection of counter's events the may trigger an interrupt
   */
  typedef enum {
      PCNT_EVT_THRES_1 = BIT(2),           /*!< PCNT watch point event: threshold1 value event */
      PCNT_EVT_THRES_0 = BIT(3),           /*!< PCNT watch point event: threshold0 value event */
      PCNT_EVT_L_LIM = BIT(4),             /*!< PCNT watch point event: Minimum counter value */
      PCNT_EVT_H_LIM = BIT(5),             /*!< PCNT watch point event: Maximum counter value */
      PCNT_EVT_ZERO = BIT(6),              /*!< PCNT watch point event: counter value zero event */
      PCNT_EVT_MAX
  } pcnt_evt_type_t;
  
  /**
   * @brief Pulse Counter configuration for a single channel
   */
  typedef struct {
      int pulse_gpio_num;             /*!< Pulse input GPIO number, if you want to use GPIO16, enter pulse_gpio_num = 16, a negative value will be ignored */
      int ctrl_gpio_num;              /*!< Control signal input GPIO number, a negative value will be ignored */
      pcnt_ctrl_mode_t lctrl_mode;    /*!< PCNT low control mode */
      pcnt_ctrl_mode_t hctrl_mode;    /*!< PCNT high control mode */
      pcnt_count_mode_t pos_mode;     /*!< PCNT positive edge count mode */
      pcnt_count_mode_t neg_mode;     /*!< PCNT negative edge count mode */
      int16_t counter_h_lim;          /*!< Maximum counter value */
      int16_t counter_l_lim;          /*!< Minimum counter value */
      pcnt_unit_t unit;               /*!< PCNT unit number */
      pcnt_channel_t channel;         /*!< the PCNT channel */
  } pcnt_config_t;
  
  #ifdef __cplusplus
  }
  #endif