RM0017 Datasheet, PDF (247/904 Pages) STMicroelectronics – The SPC560Bx and SPC560Cx is a new family

Real Time Clock / Autonomous Periodic Interrupt (RTC/API)
RM0017
13 Real Time Clock / Autonomous Periodic Interrupt
(RTC/API)
13.1
Overview
The RTC/API is a free running counter used for time keeping applications. The RTC may be
configured to generate an interrupt at a predefined interval independent of the mode of
operation (run mode or low power mode). If in a low power mode when the RTC interval is
reached, the RTC first generates a wakeup and then assert the interrupt request. The RTC
also supports an autonomous periodic interrupt (API) function used to generate a periodic
wakeup request to exit a low power mode or an interrupt request.
13.2
Features
Features of the RTC/API include:
● 3 selectable counter clock sources
– SIRC (128 kHz)
– SXOSC (32 KHz)
– FIRC (16 MHz)
● Optional 512 prescaler and optional 32 prescaler
● 32-bit counter
– Supports times up to 1.5 months with 1 ms resolution
– Runs in all modes of operation
– Reset when disabled by software and by POR
● 12-bit compare value to support interrupt intervals of 1 s up to greater than 1 hr with 1 s
resolution
● RTC compare value changeable while counter is running
● RTC status and control register are reset only by POR
● Autonomous periodic interrupt (API)
– 10-bit compare value to support wakeup intervals of 1.0 ms to 1 s
– Compare value changeable while counter is running
● Configurable interrupt for RTC match, API match, and RTC rollover
● Configurable wakeup event for RTC match, API match, and RTC rollover
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