The present invention relates to low-power integrated circuits generally, and particulary to timekeeping circuits.
The presently preferred embodiment is a serial timekeeping chip, which can be accessed by a user, over a serial bus, to get clock and calendar information. The disclosed innovations will therefore be described in the context of that chip. However, it must be appreciated that the disclosed innovations are not by any means limited to such a context.
In describing the disclosed innovations, reference will be made to two earlier integrated circuits, the DS1215 and the DS1287. These two chips were milestones in the development of low-power timekeeping ICs. Data sheets for both these chips appeared in the 1987-88 Dallas Semiconductor Data Book. This data book appeared more than one year before the filing of the present application, and thus this data book and the DS1215 and DS1287 chips (at least in their then-current versions) are believed to be prior art to the present application. These data sheets, and the chips therein described, are hereby incorporated by reference.