esp-idf/examples/peripherals/pcnt/rotary_encoder/main/rotary_encoder_example_main.c

/*
 * SPDX-FileCopyrightText: 2010-2022 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: CC0-1.0
 */

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "esp_log.h"
#include "driver/pulse_cnt.h"

static const char *TAG = "example";

#define EXAMPLE_PCNT_HIGH_LIMIT 100
#define EXAMPLE_PCNT_LOW_LIMIT  -100

#define EXAMPLE_EC11_GPIO_A 0
#define EXAMPLE_EC11_GPIO_B 2

static bool example_pcnt_on_reach(pcnt_unit_handle_t unit, const pcnt_watch_event_data_t *edata, void *user_ctx)
{
    BaseType_t high_task_wakeup;
    QueueHandle_t queue = (QueueHandle_t)user_ctx;
    // send event data to queue, from this interrupt callback
    xQueueSendFromISR(queue, &(edata->watch_point_value), &high_task_wakeup);
    return (high_task_wakeup == pdTRUE);
}

void app_main(void)
{
    ESP_LOGI(TAG, "install pcnt unit");
    pcnt_unit_config_t unit_config = {
        .high_limit = EXAMPLE_PCNT_HIGH_LIMIT,
        .low_limit = EXAMPLE_PCNT_LOW_LIMIT,
    };
    pcnt_unit_handle_t pcnt_unit = NULL;
    ESP_ERROR_CHECK(pcnt_new_unit(&unit_config, &pcnt_unit));

    ESP_LOGI(TAG, "set glitch filter");
    pcnt_glitch_filter_config_t filter_config = {
        .max_glitch_ns = 1000,
    };
    ESP_ERROR_CHECK(pcnt_unit_set_glitch_filter(pcnt_unit, &filter_config));

    ESP_LOGI(TAG, "install pcnt channels");
    pcnt_chan_config_t chan_a_config = {
        .edge_gpio_num = EXAMPLE_EC11_GPIO_A,
        .level_gpio_num = EXAMPLE_EC11_GPIO_B,
    };
    pcnt_channel_handle_t pcnt_chan_a = NULL;
    ESP_ERROR_CHECK(pcnt_new_channel(pcnt_unit, &chan_a_config, &pcnt_chan_a));
    pcnt_chan_config_t chan_b_config = {
        .edge_gpio_num = EXAMPLE_EC11_GPIO_B,
        .level_gpio_num = EXAMPLE_EC11_GPIO_A,
    };
    pcnt_channel_handle_t pcnt_chan_b = NULL;
    ESP_ERROR_CHECK(pcnt_new_channel(pcnt_unit, &chan_b_config, &pcnt_chan_b));

    ESP_LOGI(TAG, "set edge and level actions for pcnt channels");
    ESP_ERROR_CHECK(pcnt_channel_set_edge_action(pcnt_chan_a, PCNT_CHANNEL_EDGE_ACTION_DECREASE, PCNT_CHANNEL_EDGE_ACTION_INCREASE));
    ESP_ERROR_CHECK(pcnt_channel_set_level_action(pcnt_chan_a, PCNT_CHANNEL_LEVEL_ACTION_KEEP, PCNT_CHANNEL_LEVEL_ACTION_INVERSE));
    ESP_ERROR_CHECK(pcnt_channel_set_edge_action(pcnt_chan_b, PCNT_CHANNEL_EDGE_ACTION_INCREASE, PCNT_CHANNEL_EDGE_ACTION_DECREASE));
    ESP_ERROR_CHECK(pcnt_channel_set_level_action(pcnt_chan_b, PCNT_CHANNEL_LEVEL_ACTION_KEEP, PCNT_CHANNEL_LEVEL_ACTION_INVERSE));

    ESP_LOGI(TAG, "add watch points and register callbacks");
    int watch_points[] = {EXAMPLE_PCNT_LOW_LIMIT, -50, 0, 50, EXAMPLE_PCNT_HIGH_LIMIT};
    for (size_t i = 0; i < sizeof(watch_points) / sizeof(watch_points[0]); i++) {
        ESP_ERROR_CHECK(pcnt_unit_add_watch_point(pcnt_unit, watch_points[i]));
    }
    pcnt_event_callbacks_t cbs = {
        .on_reach = example_pcnt_on_reach,
    };
    QueueHandle_t queue = xQueueCreate(10, sizeof(int));
    ESP_ERROR_CHECK(pcnt_unit_register_event_callbacks(pcnt_unit, &cbs, queue));

    ESP_LOGI(TAG, "enable pcnt unit");
    ESP_ERROR_CHECK(pcnt_unit_enable(pcnt_unit));
    ESP_LOGI(TAG, "clear pcnt unit");
    ESP_ERROR_CHECK(pcnt_unit_clear_count(pcnt_unit));
    ESP_LOGI(TAG, "start pcnt unit");
    ESP_ERROR_CHECK(pcnt_unit_start(pcnt_unit));

    // Report counter value
    int pulse_count = 0;
    int event_count = 0;
    while (1) {
        if (xQueueReceive(queue, &event_count, pdMS_TO_TICKS(1000))) {
            ESP_LOGI(TAG, "Watch point event, count: %d", event_count);
        } else {
            ESP_ERROR_CHECK(pcnt_unit_get_count(pcnt_unit, &pulse_count));
            ESP_LOGI(TAG, "Pulse count: %d", pulse_count);
        }
    }
}