A "binky" Example on ESP32 using ESP-IDF FreeRTOS, which address potential bug when man use while(1) in main_app() with vTaskDelayUntil to deal with delay job.

main.c

/* Demo program.
 * https://esp32.com/viewtopic.php?f=2&t=3389
 * esp-idf git commit: 7e8c2a9c00a6fb05cd5da306b62c4474a999b1a2
 */

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_system.h"
#include "esp_spi_flash.h"

#define BLINK_GPIO CONFIG_BLINK_GPIO

void app_main()
{
    printf("Hello world!\n");

    /* Print chip information */
    esp_chip_info_t chip_info;
    esp_chip_info(&chip_info);
    printf("This is the second test.");
    printf("This is ESP32 chip with %d CPU cores, WiFi%s%s, ",
            chip_info.cores,
            (chip_info.features & CHIP_FEATURE_BT) ? "/BT" : "",
            (chip_info.features & CHIP_FEATURE_BLE) ? "/BLE" : "");

    printf("silicon revision %d, ", chip_info.revision);

    printf("%dMB %s flash\n", spi_flash_get_chip_size() / (1024 * 1024),
            (chip_info.features & CHIP_FEATURE_EMB_FLASH) ? "embedded" : "external");

    gpio_pad_select_gpio(BLINK_GPIO);

    gpio_set_direction(BLINK_GPIO, GPIO_MODE_OUTPUT);

    TickType_t xLastWakeTime;
    xLastWakeTime = xTaskGetTickCount();

    const TickType_t xFrequency = (500 / portTICK_PERIOD_MS);
    long a = 0;
    while(1){

        /* LED off  */
        gpio_set_level(BLINK_GPIO, 0);
        vTaskDelayUntil( &xLastWakeTime, xFrequency);

        /* LED on */
        gpio_set_level(BLINK_GPIO, 1);
        vTaskDelayUntil( &xLastWakeTime, xFrequency);
        printf("Hi %ld\n",a++);
    }
}