Index: RTC.c
===================================================================
diff -u -r08a11b37a4877e676b08fa7b12aa46c064c3478b -rc59e80e750af23726415d960d6776a452e37758f
--- RTC.c	(.../RTC.c)	(revision 08a11b37a4877e676b08fa7b12aa46c064c3478b)
+++ RTC.c	(.../RTC.c)	(revision c59e80e750af23726415d960d6776a452e37758f)
@@ -116,9 +116,9 @@
 #define TEN                                 10U                         ///< Ten
 #define YEAR_2000                           2000U                       ///< Year 2000
 #ifndef USE_LIBRARY_TIME_FUNCTIONS
-#define EPOCH_YEAR                          1970U                       ///< Reference year to calculate epoch (1970)
+    #define EPOCH_BASE_YEAR                 1970U                       ///< Reference year to calculate epoch (1970)
 #else
-#define EPOCH_YEAR                          1900U                       ///< Reference year to calculate epoch (1900)
+    #define EPOCH_BASE_YEAR                 1900U                       ///< Reference year to calculate epoch (1900)
 #define YEAR_1900_TO_1970_SECONDS_DIFF      2208988800U                 ///< Difference in seconds from 1/1/1900 to 1/1/1970 (2208988800)
 /// Six hour offset is needed because TI library works in CST.
 #define OFFSET_6_HRS                        (6 * MIN_PER_HOUR * SEC_PER_MIN)
@@ -843,23 +843,24 @@
 static U32 convertDateTime2Epoch( RTC_TIMESTAMP_T dateTime )
 {
     U32 epoch;
-    U32 secs  = dateTime.seconds;
-    U32 mins  = dateTime.minutes;
-    U32 hrs   = dateTime.hours;
-    U32 days  = dateTime.days;
-    U32 mos   = dateTime.months - 1;  // convert months from 1..12 to 0..11
-    U32 yrs   = dateTime.years - EPOCH_YEAR;
-    U32 lyrs  = ( yrs / 4 ) + ( yrs % 4 > 2 ? 1 : 0 );
-    BOOL leap = ( dateTime.years % 4 == 0 ? TRUE : FALSE );
     U32 i, dayCnt;
+    U32 secs  = dateTime.seconds;     // Expecting seconds to be 0..59.
+    U32 mins  = dateTime.minutes;     // Expecting minutes to be 0..59.
+    U32 hrs   = dateTime.hours;       // Expecting hours to be 0..23.
+    U32 days  = dateTime.days - 1;    // Expecting days to be 1..31.  Current (partial) day covered by hrs, min, sec so subtract current day.
+    U32 yrs   = dateTime.years + YEAR_2000 - EPOCH_BASE_YEAR;  // Expecting 2-digit year - no century from our RTC - so must assume year is >= 2000 - then subtract epoch base year.
+    U32 lyrs  = ( yrs / 4 ) + ( yrs % 4 > 2 ? 1 : 0 );         // First leap year after epoch base year (1970) is 1972 (so every 3rd of every 4 years).
+    BOOL leap = ( dateTime.years % 4 == 0 ? TRUE : FALSE );
 
+    // Compute number of full days since start of given year.
     daysInMonth[ LEAP_YEAR_MONTH ] = ( TRUE == leap ? 29 : 28 );
     dayCnt = 0;
-    for ( i = 0; i <= dateTime.months; i++ )
+    for ( i = 1; i < dateTime.months; i++ ) // Expecting months to be 1..12
     {
-        dayCnt += daysInMonth[ i ];
+        dayCnt += daysInMonth[ i-1 ];
     }
 
+    // Compute epoch from given date/time.
     epoch = secs + ( mins * SEC_PER_MIN ) + ( hrs * SECS_IN_HOUR );
     epoch += ( days * SECONDS_IN_A_DAY );
     epoch += ( dayCnt * SECONDS_IN_A_DAY );
@@ -896,7 +897,7 @@
     U32 mins       = oneHrEpoch / SEC_PER_MIN;
     U32 secs       = oneHrEpoch - ( mins * SEC_PER_MIN );
 
-    dtTime.years = EPOCH_YEAR + wholeYears;
+    dtTime.years = EPOCH_BASE_YEAR + wholeYears;
     dtTime.months = 0;
     dayCnt = 0;
     daysInMonth[ LEAP_YEAR_MONTH ] = ( TRUE == leapYear ? 29 : 28 );
@@ -936,7 +937,7 @@
     // In epoch conversion, the months are 0-11
     // so the months is decremented
     t.tm_mon  = RTCTimestampStruct.months - 1;
-    t.tm_year = RTCTimestampStruct.years + YEAR_2000 - EPOCH_YEAR;
+    t.tm_year = RTCTimestampStruct.years + YEAR_2000 - EPOCH_BASE_YEAR;
     // Disabled daylight saving
     // If daylight saving is not disabled, MinGW in VectorCAST
     // may or may not calculate the value right
@@ -973,11 +974,11 @@
 
     // Convert epoch to date/time structure
     epoch += YEAR_1900_TO_1970_SECONDS_DIFF;
-    epoch -= OFFSET_6_HRS;  // TODO - why is this needed?
+    epoch -= OFFSET_6_HRS;  // For some reason, TI works in CST time zone instead of GMT
     ptm = gmtime( &epoch );
     // Copy date/time stamp to our structure
-    RTCNewTimestampStruct.years = ptm->tm_year + EPOCH_YEAR;  // epoch is seconds from 1/1/1900.
-    RTCNewTimestampStruct.months = ptm->tm_mon + 1;           // months from gmtime() are 0..11 - convert to 1..12.
+    RTCNewTimestampStruct.years = ptm->tm_year + EPOCH_BASE_YEAR;  // epoch is seconds from 1/1/1900.
+    RTCNewTimestampStruct.months = ptm->tm_mon + 1;                // months from gmtime() are 0..11 - convert to 1..12.
     RTCNewTimestampStruct.days = ptm->tm_mday;
     RTCNewTimestampStruct.hours = ptm->tm_hour;
     RTCNewTimestampStruct.minutes = ptm->tm_min;