STM32L4实时时钟模块(RTC)介绍.pdf

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1、STM32L4Real-TimeClock(RTC)RTCFeatures(1/2)63•Ultra-lowpowerbatterysupplycurrent.•CalendarwithSubseconds,seconds,minutes,hours,weekday,date,month,andyear.•Daylightsavingcompensationprogrammablebysoftware•Twoprogrammablealarmswithinterruptfunction.Thealarmscanbetriggeredbyanycombinationofthecalendarfi

2、elds.•Aperiodicflagtriggeringanautomaticwakeupinterrupt.Thisflagisissuedbya16-bitauto-reloadtimerwithprogrammableresolution.Thistimerisalsocalled‘wakeuptimer’.•Asecondclocksource(50or60Hz)canbeusedtoupdatethecalendar.•Maskableinterrupts/events:•AlarmA,AlarmB,Wakeupinterrupt,Time-stamp,Tamperdetectio

3、n•Digitalcalibrationcircuit(periodiccountercorrection)toachieve0.95ppmaccuracy•Time-stampfunctionforeventsavingwithsubsecondprecision(1event)•32backupregisters(128bytes)whichareresetwhenantamperdetectioneventoccurs.PresentationTitle02/07/2015RTCFeatures(2/2)64•Alternatefunctionoutputs:•RTC_CALIB:512

4、Hzor1Hzclockoutput(withanLSEfrequencyof32.768kHz).ItisroutedtothedeviceRTC_OUToutput.•RTC_ALARM:AlarmA,Bflagoutput.ItisroutedtothedeviceRTC_OUToutput.•Alternatefunctioninputs:•RTC_TAMP1:tamper1eventdetection.•RTC_TAMP2:tamper2eventdetection.•RTC_TAMP3:tamper3eventdetection.•RTC_TS:timestampeventdete

5、ction.•RTC_REFIN:referenceclockinput.•TheRTCclocksourcecouldbeanyofthefollowingthree:•LSEoscillatorclock:availableinallLPmodes+VBAT.•LSIoscillatorclock:availableinallLPmodesexceptShutdown.•HSEdividedby32inclockcontroller.PresentationTitle02/07/2015RTCoverviewacrossfamilies(1/2)6565STM32F4xSTM32L1xST

6、M32L4xRTCinVBATYESCalendarinBCDYESCalendarSubsecondsYESaccessResolutiondowntoRTCCLKCalendarsynchronizationYESontheflyAlarmoncalendar2w/subsecondsCalendarCalibwindow:8s/16s/32sCalibrationCalibrationstep:3.81ppm/1.91ppm/0.95ppmRange[-480ppm+480ppm]RTCoverviewacrossfamilies(2/2)6666STM32F4xSTM32L1xSTM3

7、2L4xSynchronizationonYESmainsPeriodicwakeupYESTimestampYESSec,Min,Hour,Date,SubsecondsTimestamponVBATNONoVBATYESswitchTamper3pins/2events3pins/3eventsEdgeorLevelDetectionwithConfigurablefilteringExter