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81 lines
2.5 KiB
81 lines
2.5 KiB
#ifndef ntp_time_h
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#define ntp_time_h
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#include <WiFiUdp.h>
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// NTP Servers:
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static const char ntpServerName[] = "0.uk.pool.ntp.org";
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const int timeZone = 0;
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unsigned int localPort = 8888; // local port to listen for UDP packets
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/*-------- NTP code ----------*/
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const int NTP_PACKET_SIZE = 48; // NTP time is in the first 48 bytes of message
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byte packetBuffer[NTP_PACKET_SIZE]; //buffer to hold incoming & outgoing packets
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WiFiUDP udpNtp;
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// send an NTP request to the time server at the given address
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void sendNTPpacket(IPAddress &address)
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{
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// set all bytes in the buffer to 0
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memset(packetBuffer, 0, NTP_PACKET_SIZE);
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// Initialize values needed to form NTP request
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// (see URL above for details on the packets)
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packetBuffer[0] = 0b11100011; // LI, Version, Mode
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packetBuffer[1] = 0; // Stratum, or type of clock
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packetBuffer[2] = 6; // Polling Interval
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packetBuffer[3] = 0xEC; // Peer Clock Precision
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// 8 bytes of zero for Root Delay & Root Dispersion
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packetBuffer[12] = 49;
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packetBuffer[13] = 0x4E;
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packetBuffer[14] = 49;
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packetBuffer[15] = 52;
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// all NTP fields have been given values, now
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// you can send a packet requesting a timestamp:
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udpNtp.beginPacket(address, 123); //NTP requests are to port 123
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udpNtp.write(packetBuffer, NTP_PACKET_SIZE);
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udpNtp.endPacket();
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}
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time_t getNtpTime()
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{
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if(WiFi.status() != WL_CONNECTED)
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{
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return 0;
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}
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static bool udpStarted = false;
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if(udpStarted == false)
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{
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udpStarted = true;
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udpNtp.begin(localPort);
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}
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IPAddress ntpServerIP; // NTP server's ip address
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while (udpNtp.parsePacket() > 0) ; // discard any previously received packets
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// get a random server from the pool
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WiFi.hostByName(ntpServerName, ntpServerIP);
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sendNTPpacket(ntpServerIP);
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delay(100);
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uint32_t beginWait = millis();
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while (millis() - beginWait < 1500) {
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int size = udpNtp.parsePacket();
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if (size >= NTP_PACKET_SIZE) {
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udpNtp.read(packetBuffer, NTP_PACKET_SIZE); // read packet into the buffer
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unsigned long secsSince1900;
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// convert four bytes starting at location 40 to a long integer
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secsSince1900 = (unsigned long)packetBuffer[40] << 24;
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secsSince1900 |= (unsigned long)packetBuffer[41] << 16;
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secsSince1900 |= (unsigned long)packetBuffer[42] << 8;
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secsSince1900 |= (unsigned long)packetBuffer[43];
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return secsSince1900 - 2208988800UL + timeZone * SECS_PER_HOUR;
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}
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delay(10);
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}
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return 0; // return 0 if unable to get the time
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}
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#endif //ntp_time_h
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