RM0365 Datasheet, PDF (723/1076 Pages) STMicroelectronics – This reference manual targets application developers

Real-time clock (RTC)
RM0365
27.2
RTC main features
The RTC unit main features are the following (see Figure 282: RTC block diagram):
• Calendar with subseconds, seconds, minutes, hours (12 or 24 format), day (day of
week), date (day of month), month, and year.
• Daylight saving compensation programmable by software.
• Programmable alarm with interrupt function. The alarm can be triggered by any
combination of the calendar fields.
• Automatic wakeup unit generating a periodic flag that triggers an automatic wakeup
interrupt.
• Reference clock detection: a more precise second source clock (50 or 60 Hz) can be
used to enhance the calendar precision.
• Accurate synchronization with an external clock using the subsecond shift feature.
• Digital calibration circuit (periodic counter correction): 0.95 ppm accuracy, obtained in a
calibration window of several seconds
• Time-stamp function for event saving
• Tamper detection event with configurable filter and internal pull-up
• Maskable interrupts/events:
– Alarm A
– Alarm B
– Wakeup interrupt
– Time-stamp
– Tamper detection
• Backup registers.
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