While looking around for a real nice RTC I found the ISL12022M
from Intersil fitting in my actual project (watching 5 fuel depots for my Oil heating).
This part has an internal quartz (32768 Hz), a temperature sensor (precision 0.5 °C) and 128 bytes of static RAM. The logic and RAM are battery or even gold/supercap buffered.
Since there are good precision control possibilities for the clock (http://www.intersil.com/data/an/an1400.pdf
) this electronic part maybe of interest for somebody I wrote a library (attached to this article).
The library uses the Time.h library.
Please feel free to test the code and let me know if there are bugs or if you have any suggestions what you miss in that library.