/* * Time_NTP.pde * Example showing time sync to NTP time source * * This sketch uses the Ethernet library */ #include #include #include #include byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; // NTP Servers: IPAddress timeServer(132, 163, 4, 101); // time-a.timefreq.bldrdoc.gov // IPAddress timeServer(132, 163, 4, 102); // time-b.timefreq.bldrdoc.gov // IPAddress timeServer(132, 163, 4, 103); // time-c.timefreq.bldrdoc.gov const int timeZone = 1; // Central European Time //const int timeZone = -5; // Eastern Standard Time (USA) //const int timeZone = -4; // Eastern Daylight Time (USA) //const int timeZone = -8; // Pacific Standard Time (USA) //const int timeZone = -7; // Pacific Daylight Time (USA) EthernetUDP Udp; unsigned int localPort = 8888; // local port to listen for UDP packets void setup() { Serial.begin(9600); while (!Serial) ; // Needed for Leonardo only delay(250); Serial.println("TimeNTP Example"); if (Ethernet.begin(mac) == 0) { // no point in carrying on, so do nothing forevermore: while (1) { Serial.println("Failed to configure Ethernet using DHCP"); delay(10000); } } Serial.print("IP number assigned by DHCP is "); Serial.println(Ethernet.localIP()); Udp.begin(localPort); Serial.println("waiting for sync"); setSyncProvider(getNtpTime); } time_t prevDisplay = 0; // when the digital clock was displayed void loop() { if (timeStatus() != timeNotSet) { if (now() != prevDisplay) { //update the display only if time has changed prevDisplay = now(); digitalClockDisplay(); } } } void digitalClockDisplay(){ // digital clock display of the time Serial.print(hour()); printDigits(minute()); printDigits(second()); Serial.print(" "); Serial.print(day()); Serial.print(" "); Serial.print(month()); Serial.print(" "); Serial.print(year()); Serial.println(); } void printDigits(int digits){ // utility for digital clock display: prints preceding colon and leading 0 Serial.print(":"); if(digits < 10) Serial.print('0'); Serial.print(digits); } /*-------- NTP code ----------*/ const int NTP_PACKET_SIZE = 48; // NTP time is in the first 48 bytes of message byte packetBuffer[NTP_PACKET_SIZE]; //buffer to hold incoming & outgoing packets time_t getNtpTime() { while (Udp.parsePacket() > 0) ; // discard any previously received packets Serial.println("Transmit NTP Request"); sendNTPpacket(timeServer); uint32_t beginWait = millis(); while (millis() - beginWait < 1500) { int size = Udp.parsePacket(); if (size >= NTP_PACKET_SIZE) { Serial.println("Receive NTP Response"); Udp.read(packetBuffer, NTP_PACKET_SIZE); // read packet into the buffer unsigned long secsSince1900; // convert four bytes starting at location 40 to a long integer secsSince1900 = (unsigned long)packetBuffer[40] << 24; secsSince1900 |= (unsigned long)packetBuffer[41] << 16; secsSince1900 |= (unsigned long)packetBuffer[42] << 8; secsSince1900 |= (unsigned long)packetBuffer[43]; return secsSince1900 - 2208988800UL + timeZone * SECS_PER_HOUR; } } Serial.println("No NTP Response :-("); return 0; // return 0 if unable to get the time } // send an NTP request to the time server at the given address void 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(); }