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/*
* Time_NTP.pde
* Example showing time sync to NTP time source
*
* This sketch uses the Ethenet library with the user contributed UdpBytewise extension
*/
#include <Time.h>
#include <Ethernet.h>
#include <UdpBytewise.h> // UDP library from: bjoern@cs.stanford.edu 12/30/2008
#if UDP_TX_PACKET_MAX_SIZE <64 || UDP_RX_PACKET_MAX_SIZE < 64
#error : UDP packet size to small - modify UdpBytewise.h to set buffers to 64 bytes
#endif
/*
*
* You may need to modify the UdpBytewise.h library to allow enough space in the buffers for the NTP packets.
* Open up UdpBytewse.h and set the following buffers to 64 bytes:
* #define UDP_TX_PACKET_MAX_SIZE 64
* #define UDP_RX_PACKET_MAX_SIZE 64
*/
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 192, 168, 1, 44 }; // set the IP address to an unused address on your network
byte SNTP_server_IP[] = { 192, 43, 244, 18}; // time.nist.gov
//byte SNTP_server_IP[] = { 130,149,17,21}; // ntps1-0.cs.tu-berlin.de
//byte SNTP_server_IP[] = { 192,53,103,108}; // ptbtime1.ptb.de
time_t prevDisplay = 0; // when the digital clock was displayed
const long timeZoneOffset = 0L; // set this to the offset in seconds to your local time;
void setup()
{
Serial.begin(9600);
Ethernet.begin(mac,ip);
Serial.println("waiting for sync");
setSyncProvider(getNtpTime);
while(timeStatus()== timeNotSet)
; // wait until the time is set by the sync provider
}
void loop()
{
if( now() != prevDisplay) //update the display only if the 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 function for digital clock display: prints preceding colon and leading 0
Serial.print(":");
if(digits < 10)
Serial.print('0');
Serial.print(digits);
}
/*-------- NTP code ----------*/
unsigned long getNtpTime()
{
sendNTPpacket(SNTP_server_IP);
delay(1000);
if ( UdpBytewise.available() ) {
for(int i=0; i < 40; i++)
UdpBytewise.read(); // ignore every field except the time
const unsigned long seventy_years = 2208988800UL + timeZoneOffset;
return getUlong() - seventy_years;
}
return 0; // return 0 if unable to get the time
}
unsigned long sendNTPpacket(byte *address)
{
UdpBytewise.begin(123);
UdpBytewise.beginPacket(address, 123);
UdpBytewise.write(B11100011); // LI, Version, Mode
UdpBytewise.write(0); // Stratum
UdpBytewise.write(6); // Polling Interval
UdpBytewise.write(0xEC); // Peer Clock Precision
write_n(0, 8); // Root Delay & Root Dispersion
UdpBytewise.write(49);
UdpBytewise.write(0x4E);
UdpBytewise.write(49);
UdpBytewise.write(52);
write_n(0, 32); //Reference and time stamps
UdpBytewise.endPacket();
}
unsigned long getUlong()
{
unsigned long ulong = (unsigned long)UdpBytewise.read() << 24;
ulong |= (unsigned long)UdpBytewise.read() << 16;
ulong |= (unsigned long)UdpBytewise.read() << 8;
ulong |= (unsigned long)UdpBytewise.read();
return ulong;
}
void write_n(int what, int how_many)
{
for( int i = 0; i < how_many; i++ )
UdpBytewise.write(what);
}
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