ESP8266_ SNTP（Simple Network Time Protocol）

1、SNTP Simple network time protocol

SNTP The agreement adopts client / The server How it works , With UDP Means of communication ,SNTP The server receives GPS Signal or built-in atomic clock As the time benchmark of the system .

There are many in the network SNTP The server , The client will select several SNTP Server usage . If one SNTP The server lost the external time source during operation , here SNTP The server will tell SNTP client “ I lost outside time ”. When SNTP When the client receives this message , Will choose other SNTP The server .

• In unicast mode ,SNTP Clients regularly access SNTP The server obtains accurate time information , Used to adjust the time of the client's own system , To synchronize the time .
• In broadcast mode ,SNTP The server periodically sends messages to the specified IP Broadcast address perhaps IP Multicast address .SNTP The client obtains time information by listening to these addresses .

2、 Reference resources SDK Programming manual SNTP routine

• Can make SNTP
  • Set up SNTP The server , Up to 3 individual SNTP The server , You can use the domain name or IP Address settings ;
  • initialization SNTP,sntp_init();
• Set the timer , Check SNTP Time stamp , routine 100ms Stop the timer if there is a correct time , I use it 1s loop check;
• Timer callback
  • If the timestamp is not 0, Get the current time ;

 

3、 Code 、 result

         The default is time format ：“ week month Japan Time year ”, such as “Mon Jun 25 23:13:15 2018”, Not in line with habits , Reformat to “ year month Japan week Time ”, Without this requirement, you can print directly like the above routine ;

//SNTP---------------BEGIN------------------------
//	 -----------------------------------------------			 -----------------------------------------------
//	|	   month 		|	 English abbreviation 	|	 English full name 	|			|	   week X		|	 English abbreviation 	|	 English full name 	|
//	 -----------------------------------------------			 -----------------------------------------------
//	| 	   January 		|	  Jan		|	January		|			|	   Monday 		|	  Mon		|	Monday		|
//	 -----------------------------------------------			 -----------------------------------------------
//	|	   February 		|	  Feb		|	February	|			|	   Tuesday 		|	  Tue		|	Tuesday		|
//	 -----------------------------------------------			 -----------------------------------------------
//	| 	   March 		|	  Mar		|	March		|			|	   Wednesday 		|	  Wed		|	Wednesday	|
//	 -----------------------------------------------			 -----------------------------------------------
//	| 	   April 		|	  Apr		|	April		|			|	   Thursday 		|	  Thu		|	Thursday	|
//	 -----------------------------------------------			 -----------------------------------------------
//	|  	   May 		|	  May		|	May			|			|	   Friday 		|	  Fri		|	Friday		|
//	 -----------------------------------------------			 -----------------------------------------------
//	|  	   June 		|	  June		|	June		|			|	   Saturday 		|	  Sat		|	Saturday	|
//	 -----------------------------------------------			 -----------------------------------------------
//	|  	   July 		|	  July		|	July		|			|	   Sunday 		|	  Sun		|	Sunday		|
//	 -----------------------------------------------			 -----------------------------------------------
//	|  	   August 		|	  Aug		|	Aguest		|
//	 -----------------------------------------------
//	|  	   September 		|	  Sept		|	September	|
//	 -----------------------------------------------
//	|  	   October 		|	  Oct		|	October		|
//	 -----------------------------------------------
//	|  	  November 	    |	  Nov		|	November	|
//	 -----------------------------------------------
//	|  	  December 	    |	  Dec		|	December	|
//	 -----------------------------------------------

os_timer_t timer_SNTP_check;					// testing SNTP Timer for 

void ICACHE_FLASH_ATTR timer_SNTP_check_callback(void* arg)
{
	 uint32	TimeStamp;		//  Time stamp 
	 char * Str_RealTime;	//  String of actual time 

	char * Str_Head_Week;		// 【" week "】 String first address 
	char * Str_Head_Month;		// 【" month "】 String first address 
	char * Str_Head_Day;		// 【" days "】 String first address 
	char * Str_Head_Clock;		// 【" The clock "】 String first address 
	char * Str_Head_Year;		// 【" year "】 String first address 

	char A_Str_Data[30] = {0};			// Adjust the string after the date 
	char *T_A_Str_Data = A_Str_Data;	//  Cache array pointer 

	 //  Query the current distance from the reference time (1970.01.01 00:00:00 GMT+8) The timestamp ( Company : second )
	 TimeStamp = sntp_get_current_timestamp();

	 if(TimeStamp == 0){						//  Determine whether the offset time is obtained 
//		 os_timer_arm(&timer_SNTP_check,100,0);
	 }else{
//		 os_timer_disarm(&timer_SNTP_check);

		 //  Query actual time (GMT+8): East eight ( Beijing time. )
		 Str_RealTime = sntp_get_real_time(TimeStamp);

		 // 【 The actual time 】 character string  == " Zhou   month   Japan   when : branch : second   year "
		 os_printf("SNTP_TimeStamp = %d\n",TimeStamp);		//  Time stamp 
		 os_printf("SNTP_InternetTime = %s\n",Str_RealTime);	//  The actual time 

		 // Only the number of abbreviated characters of the month is uncertain 
		 Str_Head_Week 	= Str_RealTime;							// " week "  The first address of the string 
		 Str_Head_Month = strstr(Str_Head_Week,	" ") + 1;	// " month "  The first address of the string 
		 Str_Head_Day 	= strstr(Str_Head_Month,	" ") + 1;	// " days "  The first address of the string 
		 Str_Head_Clock = strstr(Str_Head_Day,	" ") + 1;	// " The clock "  The first address of the string 
		 Str_Head_Year  = Str_Head_Clock + 9;					// year 

		 os_memcpy(T_A_Str_Data, Str_Head_Year, 4);
		 A_Str_Data[4] = ' ';
		 T_A_Str_Data += 5;
		 if(Str_Head_Day - Str_Head_Month == 4){				// Month is 3 byte 
			 os_memcpy(T_A_Str_Data, Str_Head_Month, 4);		// Much of the 1 Bytes are their own spaces 
			 T_A_Str_Data += 4;
		 }else{
			 os_memcpy(T_A_Str_Data, Str_Head_Month, 5);		// Much of the 1 Bytes are their own spaces 
			 T_A_Str_Data += 5;
		 }
		 if(Str_Head_Clock - Str_Head_Day == 2){				//day yes 1 byte 
			 os_memcpy(T_A_Str_Data, Str_Head_Day, 2);		// Much of the 1 Bytes are their own spaces 
			 T_A_Str_Data += 2;
		 }else{													//day yes 2 byte 
			 os_memcpy(T_A_Str_Data, Str_Head_Day, 3);		// Much of the 1 Bytes are their own spaces 
			 T_A_Str_Data += 3;
		 }
		 os_memcpy(T_A_Str_Data, Str_Head_Week, 4);			//
		 T_A_Str_Data += 4;

		 os_memcpy(T_A_Str_Data, Str_Head_Clock, 8);		//00:00:00
		 T_A_Str_Data += 8;
		 *T_A_Str_Data = '\0';								// 【" date "】 Add... After the string '\0'

		 os_printf("data = %s\n",A_Str_Data);
		 oled_show_string(0,2,A_Str_Data,FONT_8x16);

	 }
}

//  initialization SNTP
void ICACHE_FLASH_ATTR SNTP_initial(void)
{
	ip_addr_t * addr = (ip_addr_t *)os_zalloc(sizeof(ip_addr_t));

//	sntp_setservername(0, "us.pool.ntp.org");	//  The server _0【 domain name 】
	sntp_setservername(0, "0.cn.pool.ntp.org");	//  The server _0【 domain name 】
	sntp_setservername(1, "ntp.sjtu.edu.cn");	//  The server _1【 domain name 】
	ipaddr_aton("210.72.145.44", addr);			//  dotted decimal  => 32 Bit binary 
	sntp_setserver(2, addr);					//  The server _2【IP Address 】
	os_free(addr);								//  Release addr

	sntp_init();								// SNTP initialization API

	os_timer_disarm(&timer_SNTP_check);
	os_timer_setfn(&timer_SNTP_check,timer_SNTP_check_callback,NULL);
	os_timer_arm(&timer_SNTP_check,1000,1);		//1000ms
}

//SNTP-------------------END--------------------------------

 

Reference link ：

sntp_ Baidu Encyclopedia (baidu.com)