W5100 NTP Client (and DHCP) Demo

#include <math.h>

#include <OneWire.h>

#include <Wire.h>  // Comes with Arduino IDE

#include <SPI.h>

#include <Ethernet.h>

#include <EthernetUdp.h>

#include "RTClib.h"  // Credit: Adafruit





RTC_DS1307 RTC;





/* ******** Ethernet Card Settings ******** */

// Set this to your Ethernet Card Mac Address

byte mac[] = {

  0x01, 0x02, 0x03, 0x04, 0x05, 0x06

};



// Initialize the Ethernet server library

// with the IP address and port you want to use

// (port 80 is default for HTTP):

unsigned int ifacePort = 80; // port to webportal interface

EthernetServer server(ifacePort);



// NTP Client

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

IPAddress timeServer(194,109,6,2); //ntp.xs4all.nl but you can cange in any public ntp server.

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;



long timeZoneOffset = 3600L; //Winter (original) time Europe

boolean networkConnection = true;





void setup() {

  Serial.begin(9600);



  // Instantiate the RTC

  Wire.begin();

  RTC.begin();





  // Check if the RTC is running.

  if (! RTC.isrunning()) {

    Serial.println("RTC is NOT running");

  } else {

    Serial.println("RTC present");

  }





  Serial.println(F("\n[testDHCP]"));



  // Ethernet shield setup

  int i = 1;

  int DHCP = 0;

   //Try to get dhcp settings 3 times before giving up

  Serial.println("Trying to resolve DHCP 3 times.");

  while( DHCP == 0 && i < 5){

    Serial.print("Trying to resolve DHCP attempt nr. ");

    Serial.println(i);



    delay(1000);

    DHCP = Ethernet.begin(mac);

    i++;

  }

  if(!DHCP){

    Serial.println("DHCP FAILED");

    networkConnection = false;

    delay(5000);







  } else {

    Udp.begin(localPort); //Net client added 10-11-2015

    Serial.println("DHCP Success");

    Serial.println(Ethernet.localIP());

    

    uint32_t ipAddress = Ethernet.localIP();

    uint8_t *ipPtr = (uint8_t*) &ipAddress;

    String stripAddress = String(ipPtr[0], DEC) + "." + String(ipPtr[1], DEC) + "." + String(ipPtr[2], DEC) + "." + String(ipPtr[3], DEC);



    //you can output this to lcd, oled or 7-segment

    String ip0 = String(ipPtr[0], DEC);

    String ip1 = String(ipPtr[1], DEC);

    String ip2 = String(ipPtr[2], DEC);

    String ip3 = String(ipPtr[3], DEC);

    }

  }





  //Get time from DS3231

  DateTime now = RTC.now();

  unsigned long epoch  = now.unixtime();





  //If network connection is true, sync with ntp server

  if (networkConnection) {epoch  = getNtpTime();}

  if (epoch == 0) {DateTime now = RTC.now(); epoch  = now.unixtime();} //sync failed, use DS3231 time instead



  //Check summer / winter time

  if (adjustDstEurope()) {epoch = epoch + 3600; timeZoneOffset = 7200L;}

  RTC.adjust(epoch);

  now = RTC.now();



  Serial.println(epoch);

} //End of setup





unsigned long getNtpTime()

{

    sendNTPpacket(timeServer); // send an NTP packet to a time server



    // wait to see if a reply is available

  delay(1000);  

  if ( Udp.parsePacket() ) {  

    // 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 timeFromNTP = highWord << 16 | lowWord;

    const unsigned long seventyYears = 2208988800UL;

    return timeFromNTP - seventyYears + timeZoneOffset;  

  }



}





// 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

  Udp.write(packetBuffer,NTP_PACKET_SIZE);

  Udp.endPacket(); 

}





boolean adjustDstEurope()

{

  // Get the current time

  DateTime now = RTC.now();   

  // last sunday of march

  int beginDSTDate= (31 - (5* now.year() /4 + 4) % 7);

  int beginDSTMonth=3;

  //last sunday of october

  int endDSTDate= (31 - (5 * now.year() /4 + 1) % 7);

  int endDSTMonth=10;

  // DST is valid as:

  if (((now.month() > beginDSTMonth) && (now.month() < endDSTMonth))

    || ((now.month() == beginDSTMonth) && (now.day() >= beginDSTDate))

    || ((now.month() == endDSTMonth) && (now.day() < endDSTDate)))

    return true; // DST europe = GMT +2

  else return false; // nonDST europe = GMT +1

}





void loop() {

  // Get the current time

  DateTime now = RTC.now();   



  unsigned long newHour = now.hour();

  unsigned long newMinute = now.minute();

  unsigned long newSecond = now.second();

  unsigned long newYear = now.year();

  unsigned long newMonth = now.month();

  unsigned long newDay = now.day();



  int hour1    = (newHour%10);

  int hour10   = (newHour/10);

  int minute1  = (newMinute%10);

  int minute10 = (newMinute/10);

  int second1  = (newSecond%10);

  int second10 = (newSecond/10);

  int year1    = (newYear%10);

  int year10   = ((newYear/10)%10);

  int year100  = ((newYear/100)%10);

  int year1000 = (newYear/1000);

  int month1   = (newMonth%10);

  int month10  = (newMonth/10);

  int day1     = (newDay%10);

  int day10    = (newDay/10);





  //Output to serial console, but you can use lcd, oled or 7-segment

  Serial.print(hour10);

  Serial.print(hour1);

  Serial.print(":");

  Serial.print(minute10);

  Serial.print(minute1);

  Serial.print(":");

  Serial.print(second10);

  Serial.print(second1);

  Serial.print(" ");

  Serial.print(day10);

  Serial.print(day1);

  Serial.print("-");

  Serial.print(month10);

  Serial.print(month1);

  Serial.print("-");

  Serial.print(year1000);

  Serial.print(year100);

  Serial.print(year10);

  Serial.println(year1);



  delay(1000);

}