mirror of
https://github.com/DuRuofu/ESP32-Guide.git
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264 lines
7.6 KiB
Markdown
264 lines
7.6 KiB
Markdown
# ESP32网络入门 - SNTP校时
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> [!TIP] 🚀 SNTP校时 | 精确同步ESP32的系统时间
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> - 💡 **碎碎念**😎：本节将介绍如何使用 SNTP 协议实现 ESP32 的系统时间同步。你将学习如何连接到网络时间服务器，并校准 ESP32 的本地时间。
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> - 📺 **视频教程**：暂无
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> - 💾 **示例代码**：[ESP32-Guide/code/05.wifi/sntp](https://github.com/DuRuofu/ESP32-Guide/tree/main/code/05.wifi/sntp)
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## 一、介绍
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SNTP 指 **简单网络时间协议**（Simple Network Time Protocol），一个合格的物联网设备，少不了一个准确的钟。通过SNTP，可以使ESP32设备通过网络校准本地时间。使用起来也非常简单。
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## 二、使用
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#### 2.1 初始化特定的 SNTP 服务器
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要初始化特定的 SNTP 服务器并启动 SNTP 服务，只需创建有特定服务器名称的默认 SNTP 服务器配置，然后调用 [`esp_netif_sntp_init()`](https://docs.espressif.com/projects/esp-idf/zh_CN/latest/esp32s3/api-reference/network/esp_netif.html#_CPPv419esp_netif_sntp_initPK17esp_sntp_config_t "esp_netif_sntp_init") 注册该服务器并启动 SNTP 服务。
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```c
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esp_sntp_config_t config = ESP_NETIF_SNTP_DEFAULT_CONFIG("pool.ntp.org");
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esp_netif_sntp_init(&config);
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```
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#### 2.1 启动 SNTP 服务
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```c
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// Start SNTP
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esp_netif_sntp_start();
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```
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#### 2.3 同步时间
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```c
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// wait for time to be set
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time_t now = 0;
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struct tm timeinfo = {0};
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int retry = 0;
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const int retry_count = 15;
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while (esp_netif_sntp_sync_wait(2000 / portTICK_PERIOD_MS) == ESP_ERR_TIMEOUT && ++retry < retry_count)
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{
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ESP_LOGI(TAG, "Waiting for system time to be set... (%d/%d)", retry, retry_count);
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}
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time(&now);
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localtime_r(&now, &timeinfo);
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```
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#### 2.4 其他
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设置时区：
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1. 调用 `setenv()`，将 `TZ` 环境变量根据设备位置设置为正确的值。时间字符串的格式与 [GNU libc 文档](https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html) 中描述的相同（但实现方式不同）。
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2. 调用 `tzset()`，为新的时区更新 C 库的运行数据。
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例：
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```c
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// Set timezone to Beijing time
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setenv("TZ", "CST-8", 1); // CST-8 represents China Standard Time (UTC+8)
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tzset();
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```
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## 三、示例
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```c
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#include <stdio.h>
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#include <string.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/event_groups.h"
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#include "esp_wifi.h"
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#include "esp_log.h"
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#include "esp_event.h"
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#include "nvs_flash.h"
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#include "esp_mac.h"
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#include "esp_netif.h"
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#include <sys/socket.h>
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#include "esp_netif_sntp.h"
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#include "lwip/ip_addr.h"
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#include "esp_sntp.h"
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// 要连接的WIFI
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#define ESP_WIFI_STA_SSID "duruofu"
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#define ESP_WIFI_STA_PASSWD "1234567890"
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static const char *TAG = "main";
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void time_sync_notification_cb(struct timeval *tv)
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{
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ESP_LOGI(TAG, "Notification of a time synchronization event");
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}
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static void print_servers(void)
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{
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ESP_LOGI(TAG, "List of configured NTP servers:");
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for (uint8_t i = 0; i < SNTP_MAX_SERVERS; ++i)
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{
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if (esp_sntp_getservername(i))
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{
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ESP_LOGI(TAG, "server %d: %s", i, esp_sntp_getservername(i));
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}
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else
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{
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// we have either IPv4 or IPv6 address, let's print it
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char buff[INET6_ADDRSTRLEN];
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ip_addr_t const *ip = esp_sntp_getserver(i);
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if (ipaddr_ntoa_r(ip, buff, INET6_ADDRSTRLEN) != NULL)
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ESP_LOGI(TAG, "server %d: %s", i, buff);
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}
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}
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}
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static void obtain_time(void)
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{
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// Set timezone to Beijing time
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setenv("TZ", "CST-8", 1); // CST-8 represents China Standard Time (UTC+8)
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tzset();
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ESP_LOGI(TAG, "Initializing SNTP");
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esp_sntp_config_t config = ESP_NETIF_SNTP_DEFAULT_CONFIG("cn.pool.ntp.org");
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config.sync_cb = time_sync_notification_cb;
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config.renew_servers_after_new_IP = true,
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// Initialize SNTP with the provided configuration
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esp_netif_sntp_init(&config);
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// Start SNTP
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esp_netif_sntp_start();
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ESP_LOGI(TAG, "Initializing and starting SNTP");
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print_servers();
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// wait for time to be set
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time_t now = 0;
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struct tm timeinfo = {0};
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int retry = 0;
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const int retry_count = 15;
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while (esp_netif_sntp_sync_wait(2000 / portTICK_PERIOD_MS) == ESP_ERR_TIMEOUT && ++retry < retry_count)
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{
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ESP_LOGI(TAG, "Waiting for system time to be set... (%d/%d)", retry, retry_count);
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}
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time(&now);
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localtime_r(&now, &timeinfo);
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// Print current time
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char strftime_buf[64];
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strftime(strftime_buf, sizeof(strftime_buf), "%c", &timeinfo);
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ESP_LOGI(TAG, "Current time: %s", strftime_buf);
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}
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void WIFI_CallBack(void *event_handler_arg, esp_event_base_t event_base, int32_t event_id, void *event_data)
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{
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static uint8_t connect_count = 0;
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// WIFI 启动成功
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if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START)
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{
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ESP_LOGI("WIFI_EVENT", "WIFI_EVENT_STA_START");
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ESP_ERROR_CHECK(esp_wifi_connect());
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}
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// WIFI 连接失败
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if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED)
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{
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ESP_LOGI("WIFI_EVENT", "WIFI_EVENT_STA_DISCONNECTED");
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connect_count++;
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if (connect_count < 6)
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{
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vTaskDelay(1000 / portTICK_PERIOD_MS);
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ESP_ERROR_CHECK(esp_wifi_connect());
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}
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else
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{
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ESP_LOGI("WIFI_EVENT", "WIFI_EVENT_STA_DISCONNECTED 10 times");
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}
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}
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// WIFI 连接成功(获取到了IP)
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if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP)
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{
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ESP_LOGI("WIFI_EVENT", "WIFI_EVENT_STA_GOT_IP");
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ip_event_got_ip_t *info = (ip_event_got_ip_t *)event_data;
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ESP_LOGI("WIFI_EVENT", "got ip:" IPSTR "", IP2STR(&info->ip_info.ip));
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// 更新时间
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obtain_time();
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}
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}
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// wifi初始化
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static void wifi_sta_init(void)
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{
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ESP_ERROR_CHECK(esp_netif_init());
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// 注册事件(wifi启动成功)
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ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT, WIFI_EVENT_STA_START, WIFI_CallBack, NULL, NULL));
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// 注册事件(wifi连接失败)
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ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT, WIFI_EVENT_STA_DISCONNECTED, WIFI_CallBack, NULL, NULL));
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// 注册事件(wifi连接失败)
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ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT, IP_EVENT_STA_GOT_IP, WIFI_CallBack, NULL, NULL));
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// 初始化STA设备
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esp_netif_create_default_wifi_sta();
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/*Initialize WiFi */
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wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
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// WIFI_INIT_CONFIG_DEFAULT 是一个默认配置的宏
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ESP_ERROR_CHECK(esp_wifi_init(&cfg));
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//----------------配置阶段-------------------
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// 初始化WIFI设备( 为 WiFi 驱动初始化 WiFi 分配资源，如 WiFi 控制结构、RX/TX 缓冲区、WiFi NVS 结构等，这个 WiFi 也启动 WiFi 任务。必须先调用此API，然后才能调用所有其他WiFi API)
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ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
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// STA详细配置
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wifi_config_t sta_config = {
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.sta = {
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.ssid = ESP_WIFI_STA_SSID,
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.password = ESP_WIFI_STA_PASSWD,
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.bssid_set = false,
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},
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};
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ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &sta_config));
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//----------------启动阶段-------------------
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ESP_ERROR_CHECK(esp_wifi_start());
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//----------------配置省电模式-------------------
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// 不省电(数据传输会更快)
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ESP_ERROR_CHECK(esp_wifi_set_ps(WIFI_PS_NONE));
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}
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void app_main(void)
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{
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// Initialize NVS
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esp_err_t ret = nvs_flash_init();
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if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND)
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{
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ESP_ERROR_CHECK(nvs_flash_erase());
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ret = nvs_flash_init();
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}
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ESP_ERROR_CHECK(ret);
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// 创建默认事件循环
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ESP_ERROR_CHECK(esp_event_loop_create_default());
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// 配置启动WIFI
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wifi_sta_init();
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// 使用SNTP校准时间
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}
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```
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效果：
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# 参考链接
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1. https://docs.espressif.com/projects/esp-idf/zh_CN/latest/esp32s3/api-reference/system/system_time.html?highlight=sntp
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2. https://github.com/espressif/esp-idf/blob/5a40bb8746633477c07ff9a3e90016c37fa0dc0c/examples/protocols/sntp/main/sntp_example_main.c |