In testing with the UdpNTPClient, I have noticed that after some time (often less that 5 to 10min)
The WiFi101 stack stops sending the NTP request packets, but return no error to the program. This has been verified using Wireshark and the test program below.
My modified test program and output.
Sending an NTP request
packet received
Seconds since Jan 1 1900 = 3677937580
Unix time = 1468948780
The UTC time is 17:19:40
Sending an NTP request
packet received
Seconds since Jan 1 1900 = 3677937591
Unix time = 1468948791
The UTC time is 17:19:51
Sending an NTP request
Sending an NTP request
packet received
Seconds since Jan 1 1900 = 3677937613
Unix time = 1468948813
The UTC time is 17:20:13
Sending an NTP request
Sending an NTP request
Sending an NTP request
Sending an NTP request
Sending an NTP request
Sending an NTP request
Sending an NTP request
Sending an NTP request
/*
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 <WiFi101.h>
#include <WiFiUdp.h>
int status = WL_IDLE_STATUS;
char ssid[] = "xxxxx"; // your network SSID (name)
char pass[] = "xxxxx"; // your network password
int keyIndex = 0; // your network key Index number (needed only for WEP)
unsigned long t1 = millis();
// My IP address for the WINC1500:
IPAddress MYip(192, 94, 167, 14);
// the DNS server address for the WINC1500:
IPAddress MYdns1(4,2,2,2);
// the GateWay address for the WINC1500:
IPAddress MYgw(192, 94, 167, 4);
// the Sub Net Mask for the Winc1500:
IPAddress MYsnm(255,255,255,0);
// DNS name of NTP server to use
const char NTPserver [] = "1.north-america.pool.ntp.org"; //"1.north-america.pool.ntp.org" us.pool.ntp.org
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] = {0}; //buffer to hold incoming and outgoing packets
//WiFiClass::setPins(int8_t cs, int8_t irq, int8_t rst, int8_t en)
// 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(115200);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
WiFi.setPins (8,7,4,2); // using a Feather with a WINC1500
// check for the presence of the shield:
if (WiFi.status() == WL_NO_SHIELD) {
Serial.println("WiFi shield not present");
// don't continue:
while (true);
}
// set manual IP address, comment this out for DHCP
WiFi.config(MYip, MYdns1, MYgw, MYsnm);
// 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()
{
// check if its time to make an NTP request
if ( (millis() - t1) > 10000)
{
t1 = millis();
// see if we are still connected
if ( (WiFi.status() == WL_CONNECTED) )
sendNTPpacket(timeServer); // send an NTP packet to a time server
else Serial.println("Not Connected");
}
// wait to see if a reply is available
//delay(1000);
if ( Udp.parsePacket() )
{
RXpacket();
}
// wait ten seconds before asking for the time again
delay(10000);
} // end of loop
void RXpacket(void)
{
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
}
// send an NTP request to the time server at the given address
unsigned long sendNTPpacket(IPAddress& address)
{
Serial.println("\nSending an NTP request");
// 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:
if (!Udp.beginPacket(address, 123)) //; //NTP requests are to port 123)
Serial.println("beginPacket error");
//delay (1000);
if (!Udp.write(packetBuffer, NTP_PACKET_SIZE) ) //;
Serial.println("write error");
//delay (1000);
if (!Udp.endPacket()) //;
Serial.println("endPacket error");
//delay (1000);
}
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");
}
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