Esp32 ultra detailed learning record: NTP synchronization time

I originally wanted to find inspiration from open source projects , however ！ That code sucks ！！！！！

Open source projects inevitably copy code , Want to know NTP How to implement it? I have to read that pile of bad code , Bother ！

Even if the open source project can ！ No, it's the same   bad ！ generation ！ code ！

Find a way to see for yourself NTP How to implement the related Library of .

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have access to aliyun Of NTP The server .

I found that many open source projects are used aliyun Of NTP The server .

Alibaba cloud NTP The server - Cloud server ECS - Alibaba cloud https://help.aliyun.com/document_detail/92704.html

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What is? NTP

NTP：Network Time Protocol（ Network time protocol ）

️ NTP Is a protocol used to synchronize computer time in the network . Its purpose is to synchronize the computer's clock to universal coordinated time UTC.

UTC：Universal Time Coordinated（ Coordinated universal time ） Based on the atomic time and second length .

GMT：Universal Time（ World time ） Based on the rotation of the earth .

Beijing time adopts the district time of Dongba district as the standard time . Beijing time is faster than world time (UTC) Good morning! 8 Hours , Beijing time. =UTC+8.

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Use NTPClient Library acquisition time

️ If you use NTPClient library , In fact, it's very simple, very simple ！！

Just a few functions in the official routine are implemented ！ Just four ！

WiFiUDP ntpUDP;    // establish UDP example 

NTPClient timeClient(ntpUDP, "europe.pool.ntp.org", 60 * 60 * 8, 60000);    //NTC
    //UDP& udp, const char* poolServerName, long timeOffset, unsigned long updateInterval

// Initialization function 
timeClient.begin();

// Acquisition time 
timeClient.update();
timeClient.getFormattedTime();

such , You can get it directly Hours ： minute ： second The format of time .

Is like ： Study ESP32 Still need to learn network protocol ！

Functions to be explained ：

NTPClient timeClient(ntpUDP, "europe.pool.ntp.org", 60 * 60 * 8, 60000);    //NTC
    //UDP& udp, const char* poolServerName, long timeOffset, unsigned long updateInterval

• ntpUDP：UDP example

• "europe.pool.ntp.org"：NTP Server address

• 60 * 60 * 8： It is the parameter needed to convert to the time of East 8th District ： second * minute * Hours

• 60000： Update time

In the library interface , Only see the week 、 when 、 branch 、 Second interface ！ No year 、 month 、 Japan .

#include <WiFi.h>
#include <WiFiUdp.h>
#include <NTPClient.h>

const char *ssid     = "<SSID>";
const char *password = "<PASSWORD>";

WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP, "europe.pool.ntp.org", 3600, 60000);

void setup()
{
  Serial.begin(115200);

  WiFi.begin(ssid, password);

  while ( WiFi.status() != WL_CONNECTED ) 
  {
    delay ( 500 );
    Serial.print ( "." );
  }

  timeClient.begin();
}

void loop() 
{
  timeClient.update();
  Serial.println(timeClient.getFormattedTime());


  delay(1000);
}

If you want to call this function similar to time interrupt every other period of time , Referential Ticker Library implements timer function .

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ESP32 Core library functions

stay ESP32 Under the core folder of time.c file . Defined configTime Function is used to configure time . You don't need to reference the header file to call the function directly .

void configTime(long gmtOffset_sec, int daylightOffset_sec, const char* server1, const char* server2, const char* server3)

• gmtOffset_sec： World time offset
• daylightOffset_sec： Time migration
• server： Server address

stay time.c In file , Other time setting functions are also provided , Including setting the time zone 、 Get the time zone and so on .

️ Get local time , Functions are also defined in time.c in , But using this function requires tm Type of structure storage time ！

tm Is defined in C++ library time.h Structural body in .

struct tm - C++ Referencehttps://cplusplus.com/reference/ctime/tm/

struct tm 
{ 　
// The following are the regular dates 
int tm_year;	/*  year , Its value is from 1900 Start  */ 
int tm_mon;		/*  month （ From January on ,0 For January ） -  The value range is [0,11] */ 　
int tm_mday;   	/*  The date of the month  -  The value range is [1,31] */ 　
int tm_hour;	/*  when  -  The value range is [0,23] */ 
int tm_min;		/*  branch  -  The value range is [0,59] */ 　　
int tm_sec;		/*  second – The value range is [0,59] */ 　　

int tm_wday;	/*  week – The value range is [0,6], among 0 For Sunday ,1 On behalf of Monday , And so on  */ 　
int tm_yday;	/*  From the annual 1 month 1 The number of days the day begins – The value range is [0,365], among 0 representative 1 month 1 Japan ,1 representative 1 month 2 Japan , And so on  */ 　
int tm_isdst;	/*  Daylight saving time identifier , When daylight saving time is implemented ,tm_isdst Being positive . No daylight saving time ,tm_isdst by 0; When you don't know the situation ,tm_isdst() Negative .*/ 　

long int tm_gmtoff;	 /* Specifies the time zone east of the date change line UTC Positive seconds in Eastern time zone or UTC Negative seconds in the Western time zone */ 　　
const char *tm_zone;     /* The name of the current time zone ( And environment variables TZ of )*/ 　
}; 

️ If it's Chinese time , It should be noted that the year 、 The time of the month ！

Example of function ：

The function here refers to ：Getting Date & Time From NTP Server With ESP32

#include "Arduino.h"
#include <WiFi.h>
#include "time.h"    //  In order to use tm Structure 

const char* ssid       = "<SSID>";
const char* password   = "<PASSWORD>";

struct tm timeinfo;
 
void setup()
{
  Serial.begin(115200);
  Serial.printf("Connecting to %s ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) 
  {
      delay(500);
      Serial.print(".");
  }
  Serial.println(" CONNECTED");
  
  configTime(60*60*8, 0, "ntp3.aliyun.com");    //  Alibaba cloud servers 
  printLocalTime();

  WiFi.disconnect(true);
  WiFi.mode(WIFI_OFF); 
}
 
void loop()
{
  struct tm timeinfo;
  if(!getLocalTime(&timeinfo))
   {
    Serial.println("Failed to obtain time");
    return;
  }
  Serial.println(&timeinfo, "%A, %Y-%m-%d %H:%M:%S");
  delay(1000);
}

Without incident , The following similar information will be printed on the serial port ：

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You can also read the structure , obtain

year = timeinfo.tm_year + 1900;    //  Year from 1900 Start 
month = timeinfo.tm_mon + 1;    // 0 Express 1 month 
week = timeinfo.tm_wday;    //  Note here that this is the number returned , Not words ！
...

But this method cannot automatically update the time , It's a little annoying ！ You can add Ticker To get the time for regular execution .

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Don't use NTP The way to get time ：API

In fact, it is similar to the previous article on knowing the weather Use the same method ：

Know the weather conditions and get ,ESP32 Get weather information ( Including source code )_ Like warm know cold blog -CSDN Blog _esp32 Get weather ESP32 Get weather information https://blog.csdn.net/qq_41650023/article/details/124697234 I found several on the Internet API The interface of ：

For example, knowing the weather API Back to JSON data ：

The data returned by Suning ：http://quan.suning.com/getSysTime.do

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You can even check the website GET Request some websites API

For example, website ： Now Beijing time Online standard Beijing time proofreading

Found on this website GET Request interface

The requested time can be found API That's it ：https://www.beijing-time.org/t/time.asp

Request return value ：

Some websites have API It's easier to find , Some are hard to find . Here is just an idea ！

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It's over at last ~

In fact, it's not difficult ~ ！

After knowing it, I found NTP This kind of thing is in ESP32 for Arduino It's so easy to realize , I thought it was hard to realize before, and I was afraid for a long time ！

This article is to provide an idea , The complete code of two implementation methods is attached , Tests are available ！ If it is applied, there will be BUG, But that doesn't matter .

OK, If you are lucky enough to be seen by your friends , I hope it helped you .

Happy today ~ Learned the knowledge of heart ~

Will continue to update about ESP32 for Arduino Some small knowledge points of ~ Because I am also taking time to learn recently ！

If this article brings you some help , Might as well spot individual Fabulous ~ Or is it spot spot Turn off notes ！~

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