ESP32非易失性存储整型数据笔记

基于ESP-IDF4.1

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

void app_main(void)
{
    // 初始化非易失性存储
    esp_err_t err = nvs_flash_init();
    if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        // NVS分区被截断，需要擦除并重新初始化
        ESP_ERROR_CHECK(nvs_flash_erase());
        err = nvs_flash_init();
    }
    ESP_ERROR_CHECK( err );

    // 打开
    printf("
");
    printf("Opening Non-Volatile Storage (NVS) handle... ");
    nvs_handle_t my_handle;
    err = nvs_open("storage", NVS_READWRITE, &my_handle);
    if (err != ESP_OK) {
        printf("Error (%s) opening NVS handle!
", esp_err_to_name(err));
    } else {
        printf("Done
");

        // 读取
        printf("Reading restart counter from NVS ... ");
        int32_t restart_counter = 0; // NVC中没有设置值得话，需要设置默认值为0
        err = nvs_get_i32(my_handle, "restart_counter", &restart_counter);
        switch (err) {
            case ESP_OK:
                printf("Done
");
                printf("Restart counter = %d
", restart_counter);
                break;
            case ESP_ERR_NVS_NOT_FOUND:
                printf("The value is not initialized yet!
");
                break;
            default :
                printf("Error (%s) reading!
", esp_err_to_name(err));
        }

        // 写入
        printf("Updating restart counter in NVS ... ");
        restart_counter++;
        err = nvs_set_i32(my_handle, "restart_counter", restart_counter);
        printf((err != ESP_OK) ? "Failed!
" : "Done
");

        //提交写入的值，其它时间提交写入没有保证
        printf("Committing updates in NVS ... ");
        err = nvs_commit(my_handle);
        printf((err != ESP_OK) ? "Failed!
" : "Done
");

        // 关闭
        nvs_close(my_handle);
    }

    printf("
");

    // 设备重启
    for (int i = 10; i >= 0; i--) {
        printf("Restarting in %d seconds...
", i);
        vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
    printf("Restarting now.
");
    fflush(stdout);
    esp_restart();
}

原文：https://gitee.com/EspressifSystems/esp-idf