main.c

/*
 * MJD HARDWARE INSTRUCTIONS:
 *   GPIO selector (Adafruit HUZZAH32 dev board)
 *       #21 = SW180 tilt sensor | KY032 obstacle sensor | SW420 Vibration Sensor
 *
 *   KY032 Sensor (or any other sensor or button that reports a digital signal 0 or 1)
 *       !pinvalue=1 no obstacle | pinvalue=0 yes obstacle
 *       Connect pin 1 (left) of the sensor to DATA
 *       Connect pin 2 (middle) of the sensor to GND
 *       Connect pin 3 (right) of the sensor to VCC
 */
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

#include "freertos/FreeRTOS.h"
#include "freertos/event_groups.h"
#include "freertos/task.h"

#include "esp_event_loop.h"
#include "esp_clk.h"
#include "esp_log.h"
#include "esp_spi_flash.h"

#include "nvs_flash.h"

static const char *TAG = "myapp";

/*
 * GPIO
 */
#define GPIO_NUM_LED    (GPIO_NUM_13)
#define GPIO_NUM_SENSOR (GPIO_NUM_21)

/*
 * RTOS
 */
#define RTOS_TASK_PRIORITY_NORMAL (5)

/*
 * MAIN
 */
SemaphoreHandle_t xSensorInterruptSemaphore = NULL;

void gpio_setup_gpiomux_sensor_to_led() {
    ESP_LOGI(TAG, "%s: entry", __FUNCTION__);

    // @special ESP32 GPIO-MUX routes the incoming sensor signal to the on-board LED.
    // @doc Only the loopback signals 224-228 can be configured to be routed from one input GPIO and directly to another output GPIO.
    // @special param3=true => invert because for example 1=nothing detected (LED off) and 0=obstance detected on the sensor (LED on).
    gpio_matrix_in(GPIO_NUM_SENSOR, SIG_IN_FUNC228_IDX, true);
    gpio_matrix_out(GPIO_NUM_LED, SIG_IN_FUNC228_IDX, false, false);
}

void gpio_setup_led() {
    ESP_LOGI(TAG, "%s: entry", __FUNCTION__);

    gpio_config_t io_conf;

    io_conf.pin_bit_mask = (1ULL << GPIO_NUM_LED);
    io_conf.mode = GPIO_MODE_OUTPUT;
    io_conf.pull_down_en = GPIO_PULLDOWN_DISABLE;
    io_conf.pull_up_en = GPIO_PULLUP_DISABLE;
    io_conf.intr_type = GPIO_INTR_DISABLE;
    gpio_config(&io_conf);
}

void gpio_setup_sensor() {
    ESP_LOGI(TAG, "%s: entry", __FUNCTION__);

    gpio_config_t io_conf;

    io_conf.pin_bit_mask = (1ULL << GPIO_NUM_SENSOR);
    io_conf.mode = GPIO_MODE_INPUT;
    io_conf.pull_up_en = GPIO_PULLUP_ENABLE;
    io_conf.pull_down_en = GPIO_PULLDOWN_DISABLE;
    // @okay GPIO_INTR_ANYEDGE @problem GPIO_INTR_POSEDGE GPIO_INTR_NEGEDGE (they both behave the same as ANYEDGE!)
    io_conf.intr_type = GPIO_INTR_ANYEDGE;
    ESP_ERROR_CHECK(gpio_config(&io_conf));
}

void IRAM_ATTR sensor_isr_handler(void* arg) {
    xSemaphoreGiveFromISR(xSensorInterruptSemaphore, NULL);
}

void gpio_semaphore_interrupt_task(void *pvParameter) {
    ESP_LOGI(TAG, "%s: entry", __FUNCTION__);

    xSensorInterruptSemaphore = xSemaphoreCreateBinary();

    ESP_ERROR_CHECK(gpio_install_isr_service(ESP_INTR_FLAG_LEVEL1)); // @doc ESP_INTR_FLAG_LEVEL1 Accept a Level 1 interrupt vector (lowest priority)
    ESP_ERROR_CHECK(gpio_isr_handler_add(GPIO_NUM_SENSOR, sensor_isr_handler, NULL));

    while (true) {
        if (xSemaphoreTake(xSensorInterruptSemaphore, portMAX_DELAY) == pdTRUE) {
            ESP_LOGI(TAG, "***semaphore taken***");
            ESP_LOGI(TAG, "***  GPIO#%d (sensor), current value: %d\n", GPIO_NUM_SENSOR, gpio_get_level(GPIO_NUM_SENSOR));
        }
    }
}

void app_main() {
    ESP_LOGI(TAG, "%s: entry", __FUNCTION__);

    gpio_setup_led();
    gpio_setup_sensor();
    gpio_setup_gpiomux_sensor_to_led();

    BaseType_t xReturned;
    xReturned = xTaskCreate(&gpio_semaphore_interrupt_task, "gpio_semaphore_interrupt_task (name)", 2048, NULL, RTOS_TASK_PRIORITY_NORMAL, NULL);
    if (xReturned == pdPASS) {
        ESP_LOGI(TAG, "OK Task has been created, and is running right now");
    }
}