ESP32非易失性存储整型数据笔记

基于ESP-IDF4.1
 1 #include <stdio.h>
 2 #include "freertos/FreeRTOS.h"
 3 #include "freertos/task.h"
 4 #include "esp_system.h"
 5 #include "nvs_flash.h"
 6 #include "nvs.h"
 7 
 8 void app_main(void)
 9 {
10     // 初始化非易失性存储
11     esp_err_t err = nvs_flash_init();
12     if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
13         // NVS分区被截断，需要擦除并重新初始化
14         ESP_ERROR_CHECK(nvs_flash_erase());
15         err = nvs_flash_init();
16     }
17     ESP_ERROR_CHECK( err );
18 
19     // 打开
20     printf("
");
21     printf("Opening Non-Volatile Storage (NVS) handle... ");
22     nvs_handle_t my_handle;
23     err = nvs_open("storage", NVS_READWRITE, &my_handle);
24     if (err != ESP_OK) {
25         printf("Error (%s) opening NVS handle!
", esp_err_to_name(err));
26     } else {
27         printf("Done
");
28 
29         // 读取
30         printf("Reading restart counter from NVS ... ");
31         int32_t restart_counter = 0; // NVC中没有设置值得话，需要设置默认值为0
32         err = nvs_get_i32(my_handle, "restart_counter", &restart_counter);
33         switch (err) {
34             case ESP_OK:
35                 printf("Done
");
36                 printf("Restart counter = %d
", restart_counter);
37                 break;
38             case ESP_ERR_NVS_NOT_FOUND:
39                 printf("The value is not initialized yet!
");
40                 break;
41             default :
42                 printf("Error (%s) reading!
", esp_err_to_name(err));
43         }
44 
45         // 写入
46         printf("Updating restart counter in NVS ... ");
47         restart_counter++;
48         err = nvs_set_i32(my_handle, "restart_counter", restart_counter);
49         printf((err != ESP_OK) ? "Failed!
" : "Done
");
50 
51         //提交写入的值，其它时间提交写入没有保证
52         printf("Committing updates in NVS ... ");
53         err = nvs_commit(my_handle);
54         printf((err != ESP_OK) ? "Failed!
" : "Done
");
55 
56         // 关闭
57         nvs_close(my_handle);
58     }
59 
60     printf("
");
61 
62     // 设备重启
63     for (int i = 10; i >= 0; i--) {
64         printf("Restarting in %d seconds...
", i);
65         vTaskDelay(1000 / portTICK_PERIOD_MS);
66     }
67     printf("Restarting now.
");
68     fflush(stdout);
69     esp_restart();
70 }
原文：https://gitee.com/EspressifSystems/esp-idf