// Date and time functions using a DS1307 RTC connected via I2C and Wire lib

#include <Wire.h>
#include "RTClib.h"

RTC_DS1307 RTC;

void setup () {
  Serial.begin(57600);
  Wire.begin();
  RTC.begin();

  if (! RTC.isrunning()) {
    Serial.println("RTC is NOT running!");
    // following line sets the RTC to the date & time this sketch was compiled
    RTC.adjust(DateTime(__DATE__, __TIME__));
  }
}

void loop () {

  DateTime now = RTC.now();

  Serial.print(now.year(), DEC);
  Serial.print('/');
  Serial.print(now.month(), DEC);
  Serial.print('/');
  Serial.print(now.day(), DEC);
  Serial.print(' ');
  Serial.print(now.hour(), DEC);
  Serial.print(':');
  Serial.print(now.minute(), DEC);
  Serial.print(':');
  Serial.print(now.second(), DEC);
  Serial.println();

  Serial.print(" since midnight 1/1/1970 = ");
  Serial.print(now.unixtime());
  Serial.print("s = ");
  Serial.print(now.unixtime() / 86400L);
  Serial.println("d");

  // calculate a date which is 7 days and 30 seconds into the future
  DateTime future (now.unixtime() + 7 * 86400L + 30);

  Serial.print(" now + 7d + 30s: ");
  Serial.print(future.year(), DEC);
  Serial.print('/');
  Serial.print(future.month(), DEC);
  Serial.print('/');
  Serial.print(future.day(), DEC);
  Serial.print(' ');
  Serial.print(future.hour(), DEC);
  Serial.print(':');
  Serial.print(future.minute(), DEC);
  Serial.print(':');
  Serial.print(future.second(), DEC);
  Serial.println();

  Serial.println();
  delay(3000);
}

// Date and time functions using a DS1307 RTC connected via I2C and Wire lib

#include <Wire.h>
#include "RTClib.h"

RTC_DS1307 RTC;

void setup () {
  Serial.begin(9600);
  Wire.begin();
  RTC.begin();
  // following line sets the RTC to the date & time this sketch was compiled
  RTC.adjust(DateTime(__DATE__, __TIME__));

}

void loop () {

}

#include <Wire.h>
#include "RTClib.h"
#include <Ethernet.h> //LIBRERIA PER ETHERNET SHIELD
#include <EthernetUdp.h> //LIBRERIA PER COMUNICAZIONE UDP
#include <SPI.h>

byte mac[] = { 0x90, 0xA2, 0xDA, 0x0D, 0x4D, 0xAF}; // Mac address shield Ethernet, si trova su di un adesivo sotto lo shield
byte ip[] = { 192, 168, 1, 1 };

RTC_DS1307 RTC;

// IMPOSTAZIONI PER LETTURA ORA DA NTP
unsigned int LocalPort = 8888; // local port to listen for UDP packets

//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
IPAddress timeServer(194, 116, 87, 4); // 0.it.pool.ntp.org

//se il server non funziona momentaneamente è necessario cambiarlo

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;
EthernetClient client; //dichiaro una variabile globale per il client ethernet

void setup () {
  Serial.begin(9600);
  Wire.begin();
  RTC.begin();

  Serial.println("Configuro la connessione con DHCP..."); // start the Ethernet connection
  Ethernet.begin(mac,ip);
  Serial.println("Connessione Configurata.");

}

void loop () {
  delay(10000);
  DateTime now = RTC.now();
  RTC.adjust(RegOra());
  data(); //stampa attraverso la seriale l'ora attuale per verificare la lettura dei dati
  delay (10000);
}

unsigned long RegOra(){ //REGOLAZIONE AUTOMATICA ORA RTC
  Udp.begin(LocalPort);
  sendNTPpacket(timeServer); // send an NTP packet to a time server
  unsigned long epoch;
  // 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 secsSince1900 = highWord << 16 | lowWord;
    //Serial.print("Seconds since Jan 1 1900 = " );
    //Serial.println(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:
    epoch = secsSince1900 - seventyYears;// + 1; //aggiunto 1 per ritardo in sincronizzazione
    // print Unix time: from 2000
    //Serial.println(epoch);

    // print the hour, minute and second:
    Serial.print("The UTC time is "); // UTC is the time at Greenwich Meridian (GMT)
    Serial.print((epoch % 86400L) / 3600); // print the hour (86400 equals secs per day)
    Serial.print(':');
    if ( ((epoch % 3600) / 60) < 10 )
      Serial.print('0'); // In the first 10 minutes of each hour, we'll want a leading '0'

    Serial.print((epoch % 3600) / 60); // print the minute (3600 equals secs per minute)
    Serial.print(':');
    if ( (epoch % 60) < 10 )
      Serial.print('0'); // In the first 10 seconds of each minute, we'll want a leading '0'

    Serial.println(epoch %60); // print the second
  }
  return(epoch);
}

void data(){

DateTime now = RTC.now();
Serial.print(now.year(), DEC);
Serial.print('/');
Serial.print(now.month(), DEC);
Serial.print('/');
Serial.print(now.day(), DEC);
Serial.print(' ');
Serial.print(now.hour(), DEC);
Serial.print(':');
Serial.print(now.minute(), DEC);
Serial.print(':');
Serial.print(now.second(), DEC);
Serial.println();
Serial.println();

/*Serial.print(" since 1970 = ");
Serial.print(now.unixtime());
Serial.print("s = ");
Serial.print(now.unixtime() / 86400L);
Serial.println("d");
Serial.println();*/
}

// 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();
}