AN1216 Datasheet, PDF (1/11 Pages) STMicroelectronics – Implementing a periodic alarm with TIMEKEEPER

AN1216
Application note
Implementing a periodic alarm with TIMEKEEPER^®
and serial real-time clocks (RTCs)
Introduction
The TIMEKEEPER^® and serial real-time clock (RTC) devices provide an alarm which can
be set either for a given time and day, or to repeat at a certain day in every month, or at a
certain hour in every day, or at a certain minute of every hour, or at a certain second of every
minute. With this functionality already provided in the hardware, the software to implement
an alarm of any given period is greatly simplified, as described in this document.
Table 1. TIMEKEEPER^® and serial RTC devices with alarm
TIMEKEEPER
Serial RTC
M48T37V/Y, M48T201V/Y
M41T62, M41T63, M41T64, M41T65, M41T66, M41T80, M41T81, M41T81S,
M41T82, M41T83, M41T93, M41T94, M41ST85W, M41ST87W
Although specifically tailored for the M48T37V/Y device, applications can be easily adapted
to use any of ST’s other TIMEKEEPER or serial RTC devices that have the alarm feature.
Some modifications in the MCU memory mapping (the TIMEKEEPER or RTC address
space) and in the MCU register mapping (such as the pointer to register address) would
need to be made.
September 2013
DocID007016 Rev 2
1/11
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