This document describes the TIMEKEEPER family of products from STMicroelectronics, which include non-volatile RAM (NVRAM) and a real-time clock (RTC), offering dedicated time-keeping and alarm functions. The document provides detailed information on the storage and access of time information, as well as the handling of century rollover.
This document details the behavior of the TIMEKEEPER family of devices from STMicroelectronics during the transition from the 20th to the 21st century. It describes how the internal registers manage the date and time, specifically focusing on the increment of the Years register and the optional Century register found in devices designed in 1997 or later.
The note provides specific instructions for users of devices lacking a Century register, recommending a manual software update method to store the century value (BCD 19 or 20) at a specific address location. It also confirms that all TIMEKEEPER devices automatically adjust for leap years until the year 2100.
Yes, all TIMEKEEPERS automatically allow for 31, 30, 29 and 28 day months (correctly adjusting for leap-years until the year 2100).
Users should store the BCD value 19 in the designated location and update it to BCD value 20 on 1st January 2000, at 12:00:01 AM.