24 récupérer l'heure sur internet : NTP		Adresses IP		protocole NTP
	Programme

La page principale ...

24 récupérer l'heure sur internet : NTP

Arduino Ethernet

Adresses IP

protocole NTP

#include <Ethernet.h>
#include <EthernetUdp.h>

Programme

// récupération temps par NTP à l'observatoire de MEUDON

#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
#include <Streaming.h>
#include <Time.h>

// Enter a MAC address, IP address and Portnumber for your Server below.
// The IP address will be dependent on your local network:
byte mac[] = {0x90,0xA2,0xDA,0x00,0xF0,0xDD} ; // Arduino Ethernet 'A' (shieldisé) 
//byte mac[] = {0x90,0xA2,0xDA,0x0D,0x62,0x46} ; // Arduino Ethernet 'B' 
// IPAddress monIP(192,168,42,101);    // réservée dans le DHCP FreeBox

// ne pas envoyer plus d'une requête toutes les 4 secondes, sinon on se fait blacklister !
 IPAddress timeServer(145, 238, 203, 10); // ntp.obspm.fr (alias, IP: 145.238.203.10):
// IPAddress timeServer(207,46,197,32); // time.windows.com 207.46.197.32 Microsoft, Redmond, Washington
// IPAddress timeServer(132, 163, 4, 101); // time-a.timefreq.bldrdoc.gov NTP server
// IPAddress timeServer(132, 163, 4, 102); // time-b.timefreq.bldrdoc.gov NTP server
// IPAddress timeServer(132, 163, 4, 103); // time-c.timefreq.bldrdoc.gov NTP server

// local port to listen for UDP packets
unsigned int localPort = 8888;      // local port to listen for UDP packets

const int NTP_PACKET_SIZE= 48; // NTP time stamp is in the first 48 bytes of the message

byte packetBuffer[ NTP_PACKET_SIZE]; //buffer to hold incoming and outgoing packets 

// A UDP instance to let us send and receive packets over UDP
EthernetUDP Udp;

//**************************************************************************************
// Pin 9 has an LED connected on Arduino Ethernet :
//int lamp=9;
int lamp=12;
boolean cligno = false;

/*
   byte send_message_trame[23];
   int  send_message_length;
   int cs_temp;
*/


int grafcet_ntp = 1;
// forcage mise à l'heure GMT
int    gmt_decalage=-2;    // heure d'été
// int   gmt_decalage=-1;    // heure d'hiver

// variables à tout faire
int i;

//**************************************************************************************
void setup() 
{
 // Open serial communications
  Serial.begin(9600); Serial << "Starting ..." << endl;

// start Ethernet and UDP
//  Ethernet.begin(mac, monIP);    // fixed address
// DHCP

   if (Ethernet.begin(mac) == 0) {
    Serial << "Failed to configure Ethernet using DHCP"<< endl;
// no point in carrying on, so do nothing forevermore:
    for(;;)
      ;
  }
/**/
Udp.begin(localPort);
}

//**************************************************************************************
void loop()
{
int ok;
switch (grafcet_ntp) {
// Ne pas faire plus d'une requête toutes les 4 secondes, au risque de se faire blacklister !
// Dans la pratique, l'horloge ADRDUINO dérive de quelques secondes par jour, 
//          une synchro horaire est très suffisante, voire trop !
// On peut tenter d'ajuster l'horloge de l'arduino en mettant en paralèlle sur l'une des
//      2 capacités du quartz de 16 Mhz un condensateur ajustable de 20 à 40 pF
//      Si l'horloge va trop lentement enlver cette capacité et la remplacer par 
//      le condensateur ajustable.

  case 1:
    if ( minute() == 59 && second() == 55) grafcet_ntp++;
    if ( second()%15 == 10) grafcet_ntp++;    // pour test, toutes les 15 secondes
    break;
  
  case 2:
    sendNTPpacket(timeServer); // send an NTP packet to a time server
    grafcet_ntp++;
    break;
  
  case 3:
  // wait to see if a reply is available
  if ( Udp.parsePacket() ) {  
    grafcet_ntp++;

// print the ARDUINO hour, minute and second:
    Serial << day() << "/" << month() << "/" << i << " " << hour() << ":" << minute() << ":" << second() << " " ;

    // We've received a packet, read the data from it
    Udp.read(packetBuffer,NTP_PACKET_SIZE);  // read the packet into the buffer

    //the timestamp starts at byte 40 of the received packet and is four bytes,
    // or two words, long. First, esxtract the two words:

    unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);
    unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]);  
    // combine the four bytes (two words) into a long integer
    // this is NTP time (seconds since Jan 1 1900):
    unsigned long secsSince1900 = highWord << 16 | lowWord;  
    Serial << " Time= " << secsSince1900 ;               

    // now convert NTP time into everyday time:
    Serial.print(" Unix_time= ");
    // Unix time starts on Jan 1 1970. In seconds, that's 2208988800:
    const unsigned long seventyYears = 2208988800UL;     
    // subtract seventy years:
    unsigned long epoch = secsSince1900 - seventyYears;  
    // print Unix time:
    Serial << epoch;                               


// UTC is the time at Greenwich Meridian (GMT)
    Serial << " UTC=" << (epoch  % 86400L) / 3600 << ':';  
    if ( ((epoch % 3600) / 60) < 10 ) {
      // In the first 10 minutes of each hour, we'll want a leading '0'
      Serial << '0';
    }
    Serial << (epoch  % 3600) / 60 << ':'; 
    if ( (epoch % 60) < 10 ) {
      // In the first 10 seconds of each minute, we'll want a leading '0'
      Serial.print('0');
    }
    Serial << epoch %60 << endl; // print the second

// mise à l'heure ARDUINO
    setTime(epoch-gmt_decalage*3600);

  }
  break;
  
  case 4:
    if (second()%15 == 0) grafcet_ntp = 1;
    break;
 } // end switch gracfet_ntp

}

//**************************************************************************************
//**************************************************************************************
// send an NTP request to the time server at the given address 
unsigned long sendNTPpacket(IPAddress& address)
{
  // set all bytes in the buffer to 0
  memset(packetBuffer, 0, NTP_PACKET_SIZE); 
  // Initialize values needed to form NTP request
  // (see URL above for details on the packets)
  packetBuffer[0] = 0b11100011;   // LI, Version, Mode
  packetBuffer[1] = 0;     // Stratum, or type of clock
  packetBuffer[2] = 6;     // Polling Interval
  packetBuffer[3] = 0xEC;  // Peer Clock Precision
  // 8 bytes of zero for Root Delay & Root Dispersion
  packetBuffer[12]  = 49; 
  packetBuffer[13]  = 0x4E;
  packetBuffer[14]  = 49;
  packetBuffer[15]  = 52;

  // all NTP fields have been given values, now
  // you can send a packet requesting a timestamp:         
  Udp.beginPacket(address, 123); //NTP requests are to port 123
//  Serial << "envoi=" << Udp.write(packetBuffer,NTP_PACKET_SIZE) << endl;
  Udp.write(packetBuffer,NTP_PACKET_SIZE);
  Udp.endPacket(); 
}
//**************************************************************************************

La page principale ...