WiFiUdpNtpClient.ino

/****************************************************************************************************************************
  WiFiUdpNtpClient.ino

  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.

  Based on and modified from WiFiNINA library https://www.arduino.cc/en/Reference/WiFiNINA
  to support nRF52, SAMD21/SAMD51, STM32F/L/H/G/WB/MP1, Teensy, etc. boards besides Nano-33 IoT, MKRWIFI1010, MKRVIDOR400, etc.

  Built by Khoi Hoang https://github.com/khoih-prog/WiFiNINA_Generic
  Licensed under MIT license

  Copyright (c) 2018 Arduino SA. All rights reserved.
  Copyright (c) 2011-2014 Arduino LLC.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*****************************************************************************************************************************/

#include "defines.h"
#include "arduino_secrets.h"

// To eliminate FW warning when using not latest nina-fw version
// To use whenever WiFi101-FirmwareUpdater-Plugin is not sync'ed with nina-fw version
#define WIFI_FIRMWARE_LATEST_VERSION        "1.4.8"

#include <SPI.h>

#if USING_WIFI101
  #include <WiFi101_Generic.h>
  #include <WiFiUdp.h>
#else
  #include <WiFiNINA_Generic.h>
  #include <WiFiUdp_Generic.h>
#endif

///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID;        // your network SSID (name)
char pass[] = SECRET_PASS;        // your network password (use for WPA, or use as key for WEP), length must be 8+

int keyIndex = 0;                     // your network key Index number (needed only for WEP)

int status = WL_IDLE_STATUS;

unsigned int localPort = 2390;        // local port to listen for UDP packets

IPAddress timeServer(132, 163, 96, 1); // 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()
{
  //Initialize serial and wait for port to open:
  Serial.begin(115200);

  while (!Serial && millis() < 5000);

  Serial.print(F("\nStart WiFiUdpNtpClient on "));
  Serial.println(BOARD_NAME);

// check for the WiFi module:
#if USING_WIFI101
  if (WiFi.status() == WL_NO_SHIELD)
#else
  Serial.println(WIFININA_GENERIC_VERSION);
  
  if (WiFi.status() == WL_NO_MODULE)
#endif
  {
    Serial.println(F("Communication with WiFi module failed!"));

    // don't continue
    while (true);
  }

  String fv = WiFi.firmwareVersion();

  if (fv < WIFI_FIRMWARE_LATEST_VERSION)
  {
    Serial.print(F("Your current firmware NINA FW v"));
    Serial.println(fv);
    Serial.print(F("Please upgrade the firmware to NINA FW v"));
    Serial.println(WIFI_FIRMWARE_LATEST_VERSION);
  }

  // attempt to connect to Wifi network:
  while (status != WL_CONNECTED)
  {
    Serial.print(F("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(F("Connected to WiFi"));
  printWiFiStatus();

  Serial.println(F("\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);

  if (Udp.parsePacket())
  {
    Serial.println(F("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(F("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(F("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
void sendNTPpacket(IPAddress& 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.beginPacket(address, 123); //NTP requests are to port 123
  Udp.write(packetBuffer, NTP_PACKET_SIZE);
  Udp.endPacket();
}

void printWiFiStatus()
{
  // print the SSID of the network you're attached to:
  Serial.print(F("SSID: "));
  Serial.println(WiFi.SSID());

  // print your board's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print(F("IP Address: "));
  Serial.println(ip);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print(F("Signal strength (RSSI):"));
  Serial.print(rssi);
  Serial.println(F(" dBm"));
}