esp32 SPIFFs 保存设备的状态参数和配置参数 idf 代码

在ESP32 IDF中使用SPIFFS(Arduino中也有SPIFFS库)进行设备状态参数和配置参数的保存需要以下步骤：

1. 配置SPIFFS文件系统

在`sdkconfig.h`中添加以下参数配置：

#define CONFIG_SPIFFS_MAX_PARTITIONS      3
#define CONFIG_SPIFFS_OBJ_NAME_LEN        32
#define CONFIG_SPIFFS_USE_MAGIC           1
#define CONFIG_SPIFFS_MAX_FILES            8
#define CONFIG_SPIFFS_PAGE_CHECK          1
#define CONFIG_SPIFFS_CACHE_WR            1
#define CONFIG_SPIFFS_CACHE_WR_PAGES      4
#define CONFIG_SPIFFS_CACHE_WR_COUNT      2
#define CONFIG_SPIFFS_CACHE_READ          1
#define CONFIG_SPIFFS_CACHE_READ_COUNT    4
#define CONFIG_SPIFFS_META_LENGTH         4
#define CONFIG_SPIFFS_USE_MTIME           1
#define CONFIG_SPIFFS_USE_DIRTY           1
#define CONFIG_SPIFFS_OBJ_META_LEN        4
#define CONFIG_SPIFFS_USE_MAGIC           1

2. 初始化SPIFFS文件系统

在代码中添加以下初始化函数：

#include "esp_spiffs.h"

void app_main()
{
    // Mount SPIFFS
    esp_vfs_spiffs_conf_t conf = {
      .base_path = "/spiffs",
      .partition_label = NULL,
      .max_files = 5,
      .format_if_mount_failed = true
    };
    esp_err_t ret = esp_vfs_spiffs_register(&conf);

    if (ret != ESP_OK) {
        if (ret == ESP_FAIL) {
            printf("Failed to mount or format filesystem\n");
        } else if (ret == ESP_ERR_NOT_FOUND) {
            printf("Failed to find SPIFFS partition\n");
        } else {
            printf("Failed to initialize SPIFFS (%s)\n", esp_err_to_name(ret));
        }
        return;
    }
}

3. 保存参数

#include "esp_spiffs.h"

void save_param(char* param_name, char* param_val) {
    FILE* f = fopen("/spiffs/params.txt", "w");
    if (f == NULL) {
        printf("Failed to open file for writing");
        return;
    }
    fprintf(f, "%s=%s\n", param_name, param_val);
    fclose(f);
}

void app_main()
{
    // Mount SPIFFS
    esp_vfs_spiffs_conf_t conf = {
      .base_path = "/spiffs",
      .partition_label = NULL,
      .max_files = 5,
      .format_if_mount_failed = true
    };
    esp_err_t ret = esp_vfs_spiffs_register(&conf);

    if (ret != ESP_OK) {
        if (ret == ESP_FAIL) {
            printf("Failed to mount or format filesystem\n");
        } else if (ret == ESP_ERR_NOT_FOUND) {
            printf("Failed to find SPIFFS partition\n");
        } else {
            printf("Failed to initialize SPIFFS (%s)\n", esp_err_to_name(ret));
        }
        return;
    }

    // Save parameter
    save_param("param1", "value1");
}

4. 读取参数

#include "esp_spiffs.h"

void read_param(char* param_name, char* param_val, size_t len) {
    FILE* f = fopen("/spiffs/params.txt", "r");
    if (f == NULL) {
        printf("Failed to open file for reading");
        return;
    }
    char line[128];
    while (fgets(line, sizeof(line), f)) {
        char* pos = strchr(line, '=');
        if (pos == NULL) {
            continue;
        }
        *pos = '\0';
        if (strcmp(line, param_name) == 0) {
            strncpy(param_val, pos + 1, len);
            break;
        }
    }
    fclose(f);
}

void app_main()
{
    // Mount SPIFFS
    esp_vfs_spiffs_conf_t conf = {
      .base_path = "/spiffs",
      .partition_label = NULL,
      .max_files = 5,
      .format_if_mount_failed = true
    };
    esp_err_t ret = esp_vfs_spiffs_register(&conf);

    if (ret != ESP_OK) {
        if (ret == ESP_FAIL) {
            printf("Failed to mount or format filesystem\n");
        } else if (ret == ESP_ERR_NOT_FOUND) {
            printf("Failed to find SPIFFS partition\n");
        } else {
            printf("Failed to initialize SPIFFS (%s)\n", esp_err_to_name(ret));
        }
        return;
    }

    // Save parameter
    save_param("param1", "value1");

    // Read parameter
    char param_val[32];
    read_param("param1", param_val, sizeof(param_val));
    printf("Param1 value: %s\n", param_val);
}