From e4cf2261fdefa080f68176495b7d73ce02929eab Mon Sep 17 00:00:00 2001
From: SukkoPera <software@sukkology.net>
Date: Mon, 29 Aug 2016 22:24:22 +0200
Subject: [PATCH] Add TimeNTP_ENC28J60 example

---
 .../TimeNTP_ENC28J60/TimeNTP_ENC28J60.ino     | 168 ++++++++++++++++++
 1 file changed, 168 insertions(+)
 create mode 100644 examples/TimeNTP_ENC28J60/TimeNTP_ENC28J60.ino

diff --git a/examples/TimeNTP_ENC28J60/TimeNTP_ENC28J60.ino b/examples/TimeNTP_ENC28J60/TimeNTP_ENC28J60.ino
new file mode 100644
index 0000000..b6ad796
--- /dev/null
+++ b/examples/TimeNTP_ENC28J60/TimeNTP_ENC28J60.ino
@@ -0,0 +1,168 @@
+/*
+ * Time_NTP.pde
+ * Example showing time sync to NTP time source
+ *
+ * Also shows how to handle DST automatically.
+ *
+ * This sketch uses the EtherCard library:
+ * http://jeelabs.org/pub/docs/ethercard/
+ */
+ 
+#include <TimeLib.h>
+#include <EtherCard.h>
+
+byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; 
+
+// NTP Server
+const char timeServer[] PROGMEM = "pool.ntp.org";
+
+const int utcOffset = 1;     // Central European Time
+//const int utcOffset = -5;  // Eastern Standard Time (USA)
+//const int utcOffset = -4;  // Eastern Daylight Time (USA)
+//const int utcOffset = -8;  // Pacific Standard Time (USA)
+//const int utcOffset = -7;  // Pacific Daylight Time (USA)
+
+// Packet buffer, must be big enough to packet and payload
+#define BUFFER_SIZE 550
+byte Ethernet::buffer[BUFFER_SIZE];
+
+const unsigned int remotePort = 123;
+
+void setup() 
+{
+  Serial.begin(9600);
+  
+  while (!Serial)    // Needed for Leonardo only
+    ;
+  delay(250);
+  
+  Serial.println("TimeNTP_ENC28J60 Example");
+  
+  if (ether.begin(BUFFER_SIZE, mac) == 0) {
+     // no point in carrying on, so do nothing forevermore:
+    while (1) {
+      Serial.println("Failed to access Ethernet controller");
+      delay(10000);
+    }
+  }
+  
+  if (!ether.dhcpSetup()) {
+    // no point in carrying on, so do nothing forevermore:
+    while (1) {
+      Serial.println("Failed to configure Ethernet using DHCP");
+      delay(10000);
+    }
+  }
+
+  ether.printIp("IP number assigned by DHCP is ", ether.myip);
+
+  Serial.println("waiting for sync");
+  //setSyncProvider(getNtpTime);            // Use this for GMT time
+  setSyncProvider(getDstCorrectedTime);     // Use this for local, DST-corrected time
+}
+
+time_t prevDisplay = 0; // when the digital clock was displayed
+
+void loop()
+{
+  if (timeStatus() != timeNotSet) {
+    if (now() != prevDisplay) { //update the display only if 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 for digital clock display: prints preceding colon and leading 0
+  Serial.print(":");
+  if(digits < 10)
+    Serial.print('0');
+  Serial.print(digits);
+}
+
+/*-------- NTP code ----------*/
+
+// SyncProvider that returns UTC time
+time_t getNtpTime()
+{
+  // Send request
+  Serial.println("Transmit NTP Request");
+  if (!ether.dnsLookup(timeServer)) {
+    Serial.println("DNS failed");
+    return 0; // return 0 if unable to get the time
+  } else {
+    //ether.printIp("SRV: ", ether.hisip);
+    ether.ntpRequest(ether.hisip, remotePort);
+  
+    // Wait for reply
+    uint32_t beginWait = millis();
+    while (millis() - beginWait < 1500) {
+      word len = ether.packetReceive();
+      ether.packetLoop(len);
+
+      unsigned long secsSince1900 = 0L;
+      if (len > 0 && ether.ntpProcessAnswer(&secsSince1900, remotePort)) {
+        Serial.println("Receive NTP Response");
+        return secsSince1900 - 2208988800UL;
+      }
+    }
+    
+    Serial.println("No NTP Response :-(");
+    return 0;
+  }
+}
+
+/* Alternative SyncProvider that automatically handles Daylight Saving Time (DST) periods,
+ * at least in Europe, see below.
+ */
+time_t getDstCorrectedTime (void) {
+  time_t t = getNtpTime ();
+
+  if (t > 0) {
+    TimeElements tm;
+    breakTime (t, tm);
+    t += (utcOffset + dstOffset (tm.Day, tm.Month, tm.Year + 1970, tm.Hour)) * SECS_PER_HOUR;
+  }
+
+  return t;
+}
+
+/* This function returns the DST offset for the current UTC time.
+ * This is valid for the EU, for other places see
+ * http://www.webexhibits.org/daylightsaving/i.html
+ * 
+ * Results have been checked for 2012-2030 (but should work since
+ * 1996 to 2099) against the following references:
+ * - http://www.uniquevisitor.it/magazine/ora-legale-italia.php
+ * - http://www.calendario-365.it/ora-legale-orario-invernale.html
+ */
+byte dstOffset (byte d, byte m, unsigned int y, byte h) {
+  // Day in March that DST starts on, at 1 am
+  byte dstOn = (31 - (5 * y / 4 + 4) % 7);
+
+  // Day in October that DST ends  on, at 2 am
+  byte dstOff = (31 - (5 * y / 4 + 1) % 7);
+
+  if ((m > 3 && m < 10) ||
+      (m == 3 && (d > dstOn || (d == dstOn && h >= 1))) ||
+      (m == 10 && (d < dstOff || (d == dstOff && h <= 1))))
+    return 1;
+  else
+    return 0;
+}
+