I'm using the hardware RTC (smaRTClock) in the IDE, but what are the Year, Month, Day, Hour, Minute, Second values shown and how are they calculated?
The RTC counts time using a standard 47-bit timer/counter and is capable of counting up to 137 years, but the interpretation of time depends upon the application. For example, a calendar developed in May 2006 will never need to show before 2006, so an RTC timer of 0x000000000000 may correspond to 00:00:00 on January 1, 2006.
The Silicon Laboratories IDE takes the values in the CAPTURE and ALARM registers to calculate the Year, Month, Day, Hour, Minute, Second values shown in the RTC Interface peripheral window. The IDE assumes that the crystal frequency used with the RTC is 32768 Hz. When a 32768 Hz crystal is used, the LSB of the CAPTURE2 and ALARM2 registers represent one second.
The date and time variables are calculated in the IDE based on the number of seconds represented in CAPTURE and ALARM, using the Coordinated Universal Time (UTC) starting point of January 1, 1970 at 00:00:00 (i.e. a zero in CAPTURE or ALARM is equivalent to this date and time).