esp-idf/components/driver/include/driver/pcnt.h

#ifndef __PCNT_H__
#define __PCNT_H__

#include <esp_types.h>
#include "esp_intr_alloc.h"
#include "esp_err.h"
#include "freertos/FreeRTOS.h"
#include "freertos/semphr.h"
#include "freertos/xtensa_api.h"
#include "soc/soc.h"
#include "soc/pcnt_periph.h"
#include "driver/gpio.h"

#ifdef __cplusplus
extern "C" {
#endif

#define PCNT_PIN_NOT_USED     (-1)  /*!< When selected for a pin, this pin will not be used */

/**
 * @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 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 */
    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 */
    PCNT_UNIT_MAX,
} pcnt_unit_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_L_LIM = 0,             /*!< PCNT watch point event: Minimum counter value */
    PCNT_EVT_H_LIM = 1,             /*!< PCNT watch point event: Maximum counter value */
    PCNT_EVT_THRES_0 = 2,           /*!< PCNT watch point event: threshold0 value event */
    PCNT_EVT_THRES_1 = 3,           /*!< PCNT watch point event: threshold1 value event */
    PCNT_EVT_ZERO = 4,              /*!< 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;

typedef intr_handle_t pcnt_isr_handle_t;

/**
 * @brief Configure Pulse Counter unit
 *        @note
 *        This function will disable three events: PCNT_EVT_L_LIM, PCNT_EVT_H_LIM, PCNT_EVT_ZERO.
 *
 * @param pcnt_config Pointer of Pulse Counter unit configure parameter
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_unit_config(const pcnt_config_t *pcnt_config);

/**
 * @brief Get pulse counter value
 *
 * @param pcnt_unit  Pulse Counter unit number
 * @param count Pointer to accept counter value
 *
 * @return  
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_get_counter_value(pcnt_unit_t pcnt_unit, int16_t* count);

/**
 * @brief Pause PCNT counter of PCNT unit
 *
 * @param pcnt_unit PCNT unit number
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_counter_pause(pcnt_unit_t pcnt_unit);

/**
 * @brief Resume counting for PCNT counter
 *
 * @param pcnt_unit PCNT unit number, select from pcnt_unit_t
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_counter_resume(pcnt_unit_t pcnt_unit);

/**
 * @brief Clear and reset PCNT counter value to zero
 *
 * @param  pcnt_unit PCNT unit number, select from pcnt_unit_t
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_counter_clear(pcnt_unit_t pcnt_unit);

/**
 * @brief Enable PCNT interrupt for PCNT unit
 *        @note
 *        Each Pulse counter unit has five watch point events that share the same interrupt.
 *        Configure events with pcnt_event_enable() and pcnt_event_disable()
 *
 * @param pcnt_unit PCNT unit number
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_intr_enable(pcnt_unit_t pcnt_unit);

/**
 * @brief Disable PCNT interrupt for PCNT unit
 *
 * @param pcnt_unit PCNT unit number
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_intr_disable(pcnt_unit_t pcnt_unit);

/**
 * @brief Enable PCNT event of PCNT unit
 *
 * @param unit PCNT unit number
 * @param evt_type Watch point event type.
 *                 All enabled events share the same interrupt (one interrupt per pulse counter unit).
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_event_enable(pcnt_unit_t unit, pcnt_evt_type_t evt_type);

/**
 * @brief Disable PCNT event of PCNT unit
 *
 * @param unit PCNT unit number
 * @param evt_type Watch point event type.
 *                 All enabled events share the same interrupt (one interrupt per pulse counter unit).
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_event_disable(pcnt_unit_t unit, pcnt_evt_type_t evt_type);

/**
 * @brief Set PCNT event value of PCNT unit
 *
 * @param unit PCNT unit number
 * @param evt_type Watch point event type.
 *                 All enabled events share the same interrupt (one interrupt per pulse counter unit).
 *
 * @param value Counter value for PCNT event
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_set_event_value(pcnt_unit_t unit, pcnt_evt_type_t evt_type, int16_t value);

/**
 * @brief Get PCNT event value of PCNT unit
 *
 * @param unit PCNT unit number
 * @param evt_type Watch point event type.
 *                 All enabled events share the same interrupt (one interrupt per pulse counter unit).
 * @param value Pointer to accept counter value for PCNT event
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_get_event_value(pcnt_unit_t unit, pcnt_evt_type_t evt_type, int16_t *value);

/**
 * @brief Register PCNT interrupt handler, the handler is an ISR.
 *        The handler will be attached to the same CPU core that this function is running on.
 *        Please do not use pcnt_isr_service_install if this function was called.
 *
 * @param fn Interrupt handler function.
 * @param arg Parameter for handler function
 * @param intr_alloc_flags Flags used to allocate the interrupt. One or multiple (ORred)
 *        ESP_INTR_FLAG_* values. See esp_intr_alloc.h for more info.
 * @param handle Pointer to return handle. If non-NULL, a handle for the interrupt will
 *        be returned here. Calling esp_intr_free to unregister this ISR service if needed,
 *        but only if the handle is not NULL.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_NOT_FOUND Can not find the interrupt that matches the flags.
 *     - ESP_ERR_INVALID_ARG Function pointer error.
 */
esp_err_t pcnt_isr_register(void (*fn)(void*), void * arg, int intr_alloc_flags, pcnt_isr_handle_t *handle);

/**
 * @brief Configure PCNT pulse signal input pin and control input pin
 *
 * @param unit PCNT unit number
 * @param channel PCNT channel number
 * @param pulse_io Pulse signal input GPIO
 * @param ctrl_io Control signal input GPIO
 *
 * @note  Set the signal input to PCNT_PIN_NOT_USED if unused.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_set_pin(pcnt_unit_t unit, pcnt_channel_t channel, int pulse_io, int ctrl_io);

/**
 * @brief Enable PCNT input filter
 *
 * @param unit PCNT unit number
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_filter_enable(pcnt_unit_t unit);

/**
 * @brief Disable PCNT input filter
 *
 * @param unit PCNT unit number
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_filter_disable(pcnt_unit_t unit);

/**
 * @brief Set PCNT filter value
 *
 * @param unit PCNT unit number
 * @param filter_val PCNT signal filter value, counter in APB_CLK cycles.
 *        Any pulses lasting shorter than this will be ignored when the filter is enabled.
 *        @note
 *        filter_val is a 10-bit value, so the maximum filter_val should be limited to 1023.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_set_filter_value(pcnt_unit_t unit, uint16_t filter_val);

/**
 * @brief Get PCNT filter value
 *
 * @param unit PCNT unit number
 * @param filter_val Pointer to accept PCNT filter value.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_get_filter_value(pcnt_unit_t unit, uint16_t *filter_val);

/**
 * @brief Set PCNT counter mode
 *
 * @param unit PCNT unit number
 * @param channel PCNT channel number
 * @param pos_mode Counter mode when detecting positive edge
 * @param neg_mode Counter mode when detecting negative edge
 * @param hctrl_mode Counter mode when control signal is high level
 * @param lctrl_mode Counter mode when control signal is low level
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_set_mode(pcnt_unit_t unit, pcnt_channel_t channel,
                        pcnt_count_mode_t pos_mode, pcnt_count_mode_t neg_mode,
                        pcnt_ctrl_mode_t hctrl_mode, pcnt_ctrl_mode_t lctrl_mode);

/**
 * @brief Add ISR handler for specified unit.
 *
 * Call this function after using pcnt_isr_service_install() to
 * install the PCNT driver's ISR handler service.
 *
 * The ISR handlers do not need to be declared with IRAM_ATTR,
 * unless you pass the ESP_INTR_FLAG_IRAM flag when allocating the
 * ISR in pcnt_isr_service_install().
 *
 * This ISR handler will be called from an ISR. So there is a stack
 * size limit (configurable as "ISR stack size" in menuconfig). This
 * limit is smaller compared to a global PCNT interrupt handler due
 * to the additional level of indirection.
 *
 * @param unit PCNT unit number
 * @param isr_handler Interrupt handler function.
 * @param args Parameter for handler function
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_isr_handler_add(pcnt_unit_t unit, void(*isr_handler)(void *), void *args);

/**
 * @brief Install PCNT ISR service.
 * @note We can manage different interrupt service for each unit.
 *       This function will use the default ISR handle service, Calling pcnt_isr_service_uninstall to
 *       uninstall the default service if needed. Please do not use pcnt_isr_register if this function was called. 
 *
 * @param intr_alloc_flags Flags used to allocate the interrupt. One or multiple (ORred)
 *        ESP_INTR_FLAG_* values. See esp_intr_alloc.h for more info.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_NO_MEM No memory to install this service
 *     - ESP_ERR_INVALID_STATE ISR service already installed
 */
esp_err_t pcnt_isr_service_install(int intr_alloc_flags);

/**
 * @brief Uninstall PCNT ISR service, freeing related resources.
 */
void pcnt_isr_service_uninstall(void);

/**
 * @brief Delete ISR handler for specified unit.
 *
 * @param unit PCNT unit number
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t pcnt_isr_handler_remove(pcnt_unit_t unit);

/**
 * @addtogroup pcnt-examples
 *
 * @{
 *
 * EXAMPLE OF PCNT CONFIGURATION
 * ==============================
 * @code{c}
 * //1. Config PCNT unit
 * pcnt_config_t pcnt_config = {
 *     .pulse_gpio_num = 4,         //set gpio4 as pulse input gpio
 *     .ctrl_gpio_num = 5,          //set gpio5 as control gpio
 *     .channel = PCNT_CHANNEL_0,         //use unit 0 channel 0
 *     .lctrl_mode = PCNT_MODE_REVERSE,   //when control signal is low, reverse the primary counter mode(inc->dec/dec->inc)
 *     .hctrl_mode = PCNT_MODE_KEEP,      //when control signal is high, keep the primary counter mode
 *     .pos_mode = PCNT_COUNT_INC,        //increment the counter
 *     .neg_mode = PCNT_COUNT_DIS,        //keep the counter value
 *     .counter_h_lim = 10,
 *     .counter_l_lim = -10,
 * };
 * pcnt_unit_config(&pcnt_config);        //init unit
 * @endcode
 *
 * EXAMPLE OF PCNT EVENT SETTING
 * ==============================
 * @code{c}
 * //2. Configure PCNT watchpoint event.
 * pcnt_set_event_value(PCNT_UNIT_0, PCNT_EVT_THRES_1, 5);   //set thres1 value
 * pcnt_event_enable(PCNT_UNIT_0, PCNT_EVT_THRES_1);         //enable thres1 event
 * @endcode
 *
 * For more examples please refer to PCNT example code in IDF_PATH/examples
 *
 * @}
 */

#ifdef __cplusplus 
}
#endif


#endif