diff options
| author | Jesse Morgan <jesse@jesterpm.net> | 2011-10-20 22:16:19 -0700 |
|---|---|---|
| committer | Jesse Morgan <jesse@jesterpm.net> | 2011-10-20 22:16:19 -0700 |
| commit | fc944ff979dbbd49a57722fe2d1d2acf47312eb4 (patch) | |
| tree | 38cc3a5c5c8f24f55068fc4ffa73d018169fc2df /libraries/Ethernet/examples/UdpNtpClient/UdpNtpClient.pde | |
Inital commit... halfway through the project
Diffstat (limited to 'libraries/Ethernet/examples/UdpNtpClient/UdpNtpClient.pde')
| -rw-r--r-- | libraries/Ethernet/examples/UdpNtpClient/UdpNtpClient.pde | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/libraries/Ethernet/examples/UdpNtpClient/UdpNtpClient.pde b/libraries/Ethernet/examples/UdpNtpClient/UdpNtpClient.pde new file mode 100644 index 0000000..1010ec9 --- /dev/null +++ b/libraries/Ethernet/examples/UdpNtpClient/UdpNtpClient.pde @@ -0,0 +1,121 @@ +/*
+
+ Udp NTP Client
+
+ Get the time from a Network Time Protocol (NTP) time server
+ Demonstrates use of UDP sendPacket and ReceivePacket
+ For more on NTP time servers and the messages needed to communicate with them,
+ see http://en.wikipedia.org/wiki/Network_Time_Protocol
+
+ created 4 Sep 2010
+ by Michael Margolis
+ modified 17 Sep 2010
+ by Tom Igoe
+
+ This code is in the public domain.
+
+ */
+
+#include <SPI.h>
+#include <Ethernet.h>
+#include <Udp.h>
+
+// Enter a MAC address and IP address for your controller below.
+// The IP address will be dependent on your local network:
+byte mac[] = {
+ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
+byte ip[] = {
+ 192,168,1,177 };
+
+
+unsigned int localPort = 8888; // local port to listen for UDP packets
+
+byte timeServer[] = {
+ 192, 43, 244, 18}; // time.nist.gov 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
+
+void setup()
+{
+ // start Ethernet and UDP
+ Ethernet.begin(mac,ip);
+ Udp.begin(localPort);
+
+ Serial.begin(9600);
+}
+
+void loop()
+{
+ sendNTPpacket(timeServer); // send an NTP packet to a time server
+
+ // wait to see if a reply is available
+ delay(1000);
+ if ( Udp.available() ) {
+ Udp.readPacket(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:
+ unsigned long epoch = secsSince1900 - seventyYears;
+ // print Unix time:
+ 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(':');
+ Serial.print((epoch % 3600) / 60); // print the minute (3600 equals secs per minute)
+ Serial.print(':');
+ Serial.println(epoch %60); // print the second
+ }
+ // wait ten seconds before asking for the time again
+ delay(10000);
+}
+
+// send an NTP request to the time server at the given address
+unsigned long sendNTPpacket(byte *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.sendPacket( packetBuffer,NTP_PACKET_SIZE, address, 123); //NTP requests are to port 123
+}
+
+
+
+
+
+
+
+
+
+
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