Update EU DST example

This time it compiles :-) and a DST demonstration on the serial port is added.

examples/EU DST example

@@ -1,5 +1,4 @@
 /* EU DST example */
-/* version 3: dd 14-10-2024 */
 
 // The RTC is kept in local winter time (standard time). This approach is key for the simplicity of this solution.
 // This code is for a DST from Last sunday in March 1:00 (am) local time until Last sunday in October 3:00 (am) local time. 
@@ -10,17 +9,19 @@ RTC_DS3231 rtc;
 //RTC_DS1307 rtc;
 
 #define USEDST  true // Use DST (true or false)
+#define BAUD   57600 // Baud rate for the serial monitor
 
 DateTime now; 
+int lastsec;
 
 DateTime dstclock(DateTime n) { // Return the given (DST adjusted) date and time according to DST settings (for extensive date and time calculations)
 
   DateTime b, e;
 
   b = DateTime(n.year(), 3, 31, 1, 0, 0); // Begin of DST: set on March 31 1:000 (am)
-  if (month(n) = 3) b = DateTime(n.year(), 3, 31 - b.dayOfTheWeek(), 1, 0, 0); // Begin of DST: adjusted to last sunday in March 1:00 (am) when actual month is March
+  if (n.month() == 3) b = DateTime(n.year(), 3, 31 - b.dayOfTheWeek(), 1, 0, 0); // Begin of DST: adjusted to last sunday in March 1:00 (am) when actual month is March
   e = DateTime(n.year(), 10, 31, 3, 0, 0); // End of DST: set on October 31 3:00 (am)
-  if (month(n) = 10) e = DateTime(n.year(), 10, 31 - e.dayOfTheWeek(), 3, 0, 0); // End of DST: adjusted to last sunday in October 3:00 (am) when actual month is October
+  if (n.month() == 10) e = DateTime(n.year(), 10, 31 - e.dayOfTheWeek(), 3, 0, 0); // End of DST: adjusted to last sunday in October 3:00 (am) when actual month is October
 
   if (USEDST && (n > b) && (n < e)) n = n + TimeSpan(0,1,0,0); // adjust to standard time if within summertime
   return n;
@@ -32,28 +33,54 @@ DateTime getclock() { // Retrieve the (DST adjusted) date and time
 
   n = rtc.now();
   b = DateTime(n.year(), 3, 31, 1, 0, 0); // Begin of DST: set on March 31 1:000 (am)
-  if (month(n) = 3) b = DateTime(n.year(), 3, 31 - b.dayOfTheWeek(), 1, 0, 0); // Begin of DST: adjusted to last sunday in March 1:00 (am) when actual month is March
+  if (n.month() == 3) b = DateTime(n.year(), 3, 31 - b.dayOfTheWeek(), 1, 0, 0); // Begin of DST: adjusted to last sunday in March 1:00 (am) when actual month is March
   e = DateTime(n.year(), 10, 31, 3, 0, 0); // End of DST: set on October 31 3:00 (am)
-  if (month(n) = 10) e = DateTime(n.year(), 10, 31 - e.dayOfTheWeek(), 3, 0, 0); // End of DST: adjusted to last sunday in October 3:00 (am) when actual month is October
+  if (n.month() == 10) e = DateTime(n.year(), 10, 31 - e.dayOfTheWeek(), 3, 0, 0); // End of DST: adjusted to last sunday in October 3:00 (am) when actual month is October
 
   if (USEDST && (n > b) && (n < e)) n = n + TimeSpan(0,1,0,0); // adjust to standard time if within summertime
   return n;
 }; 
 
 void setclock(DateTime n) { // if the clock is set during summertime then adjust the clock to standard time
 
-  if (USEDST && (n != dstclock(n)) n = n - TimeSpan(0,1,0,0); // if summertime then adjust to the standard time 
+  if (USEDST && (n != dstclock(n))) n = n - TimeSpan(0,1,0,0); // if summertime then adjust to the standard time 
   rtc.adjust(n); // Set the clock to standard time
 }; 
 
 void setup() {
   // initialise the rtc 
   rtc.begin();
-//  if (rtc.lostPower())  setclock(DateTime(F(__DATE__), F(__TIME__))); // Set date and time for use with the DS3231 RTC
-  if (!rtc.isrunning()) setclock(DateTime(F(__DATE__), F(__TIME__))); // Set date and time for use with the DS1307 RTC
+  if (rtc.lostPower()) setclock(DateTime(F(__DATE__), F(__TIME__))); // Set date and time for use with the DS3231 RTC
+  //  if (!rtc.isrunning()) setclock(DateTime(F(__DATE__), F(__TIME__))); // Set date and time for use with the DS1307 RTC
+
+  // initialise the serial port 
+  Serial.begin(BAUD);
+  Wire.begin();
+  Serial.println(""); Serial.println(""); Serial.println("---------------- New start ------------------");;
+
+  // Start the DST demonstration
+  setclock(DateTime(F(__DATE__), F(__TIME__))); // Set the clock to compile date and time
+  Serial.print("     Actual standard time:");
+  now = rtc.now(); Serial.println(now.timestamp()); // show standard (winter) time
+  Serial.print("Actual DST corrected time:");
+  now = getclock(); Serial.println(now.timestamp()); // show DST corrected time (only when in DST period, otherwise this equals the standard time)
+  Serial.println("");
+  delay(5000); 
+  Serial.println("Demonstration of the DST activation");
+  Serial.println("-----------------------------------");
+  Serial.println(" DST starts at: 2024-03-31T01:00:00");
+  Serial.println("First DST time: 2024-03-31T02:00:01");
+  Serial.println("");
+  delay(5000); 
+  setclock(DateTime(2024, 3, 31, 0, 59, 45)); // Set the time 15 soconds before DST starts
+  lastsec = now.second(); 
 }
 
 void loop() {
   now = getclock(); // read the time from the RTC and adjust for DST or
-//  now = dstclock(rtc.now()); // read the time from the RTC and adjust for DST
+  // now = dstclock(rtc.now()); // read the time from the RTC and adjust for DST
+  if (lastsec != now.second()) { // if a new second
+    Serial.println(now.timestamp()); // print the time
+    lastsec = now.second(); // store the current second
+  }
 }