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Diffstat (limited to 'libraries/WiFi/examples/WiFiUdpNtpClient/WiFiUdpNtpClient.ino')
-rw-r--r-- | libraries/WiFi/examples/WiFiUdpNtpClient/WiFiUdpNtpClient.ino | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/libraries/WiFi/examples/WiFiUdpNtpClient/WiFiUdpNtpClient.ino b/libraries/WiFi/examples/WiFiUdpNtpClient/WiFiUdpNtpClient.ino new file mode 100644 index 0000000..dd8b003 --- /dev/null +++ b/libraries/WiFi/examples/WiFiUdpNtpClient/WiFiUdpNtpClient.ino @@ -0,0 +1,182 @@ +/* + + 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 9 Apr 2012 + by Tom Igoe + + This code is in the public domain. + + */ + +#include <SPI.h> +#include <WiFi.h> +#include <WiFiUdp.h> + +int status = WL_IDLE_STATUS; +char ssid[] = "mynetwork"; // your network SSID (name) +char pass[] = "mypassword"; // your network password +int keyIndex = 0; // your network key Index number (needed only for WEP) + +unsigned int localPort = 2390; // local port to listen for UDP packets + +IPAddress timeServer(129, 6, 15, 28); // 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 + +// A UDP instance to let us send and receive packets over UDP +WiFiUDP Udp; + +void setup() +{ + // Open serial communications and wait for port to open: + Serial.begin(9600); + while (!Serial) { + ; // wait for serial port to connect. Needed for Leonardo only + } + + // check for the presence of the shield: + if (WiFi.status() == WL_NO_SHIELD) { + Serial.println("WiFi shield not present"); + // don't continue: + while(true); + } + + + // attempt to connect to Wifi network: + while ( status != WL_CONNECTED) { + Serial.print("Attempting to connect to SSID: "); + Serial.println(ssid); + // Connect to WPA/WPA2 network. Change this line if using open or WEP network: + status = WiFi.begin(ssid, pass); + + // wait 10 seconds for connection: + delay(10000); + } + + Serial.println("Connected to wifi"); + printWifiStatus(); + + Serial.println("\nStarting connection to server..."); + Udp.begin(localPort); +} + +void loop() +{ + sendNTPpacket(timeServer); // send an NTP packet to a time server + // wait to see if a reply is available + delay(1000); + Serial.println( Udp.parsePacket() ); + if ( Udp.parsePacket() ) { + Serial.println("packet received"); + // 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: + 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(':'); + if ( ((epoch % 3600) / 60) < 10 ) { + // In the first 10 minutes of each hour, we'll want a leading '0' + Serial.print('0'); + } + Serial.print((epoch % 3600) / 60); // print the minute (3600 equals secs per minute) + Serial.print(':'); + if ( (epoch % 60) < 10 ) { + // In the first 10 seconds of each minute, we'll want a leading '0' + Serial.print('0'); + } + 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(IPAddress& address) +{ + //Serial.println("1"); + // 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) + //Serial.println("2"); + 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; + + //Serial.println("3"); + + // 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 + //Serial.println("4"); + Udp.write(packetBuffer,NTP_PACKET_SIZE); + //Serial.println("5"); + Udp.endPacket(); + //Serial.println("6"); +} + + +void printWifiStatus() { + // print the SSID of the network you're attached to: + Serial.print("SSID: "); + Serial.println(WiFi.SSID()); + + // print your WiFi shield's IP address: + IPAddress ip = WiFi.localIP(); + Serial.print("IP Address: "); + Serial.println(ip); + + // print the received signal strength: + long rssi = WiFi.RSSI(); + Serial.print("signal strength (RSSI):"); + Serial.print(rssi); + Serial.println(" dBm"); +} + + + + + + + + + + |