The Intersil CDP68HC68T1 is a multifunctional CMOS real time clock with 32 bytes of general purpose RAM and various power sense and watchdog control circuitry. The main
function of the CDP68HC68T1 (henceforth referred to as the “T1”) is to keep accurate time in the form of seconds, minutes, hours, days, months and years. The interface to the T1 is through the SPI interface, available on many Intersil
68HC05 microcontrollers and other popular MCUs.
This application note deals with various techniques for keeping time with the T1, including keeping track of years into the 21st century and beyond.
This application note assumes that the reader has read and has access to the CDP68HC68T1 technical data sheet (Intersil file number 1547.3). A copy of this data sheet may be obtained from your local Intersil Corporation sales representative, downloaded from the Internet at http://www.intersil.com, or obtained from the Intersil AnswerFAX line at 1-407-724-7800.