Ultra Start 23xx Manuale Utente

September 2012 Doc ID 018624 Rev 5 1/45AN3371Application noteUsing the hardware real-time clock (RTC) in STM32 F0, F2, F3, F4 and L1 series of MCUsInt

Overview of the STM32 advanced RTC AN337110/45 Doc ID 018624 Rev 51.2 RTC alarms1.2.1 RTC alarm configurationSTM32 RTC embeds two alarms, alarm A and

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 11/45 Configuring the alarm behavior using the MSKx bitsThe alarm behavior can be

Overview of the STM32 advanced RTC AN337112/45 Doc ID 018624 Rev 5Caution: If the seconds field is selected (MSK0 bit reset in RTC_ALRMAR or RTC_ALRMB

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 13/45The Alarm sub-second can be configured using the mask ss bits in the alarm sub-secon

Overview of the STM32 advanced RTC AN337114/45 Doc ID 018624 Rev 51.3 RTC periodic wakeup unitLike many STMicroelectronics microcontrollers, the STM3

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 15/451.3.2 Maximum and minimum RTC wakeup periodThe wakeup unit clock is configured thro

Overview of the STM32 advanced RTC AN337116/45 Doc ID 018624 Rev 5Periodic timebase/wakeup configuration for clock configuration 2Figure 9 shows the p

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 17/45Summary of timebase/wakeup period extremaWhen RTCCLK= 32768 Hz, the minimum and maxi

Overview of the STM32 advanced RTC AN337118/45 Doc ID 018624 Rev 5Consequently, the coarse calibration is not adequate for a dynamic calibration (such

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 19/45A smooth calibration can be performed on the fly so that it can be changed when the

Contents AN33712/45 Doc ID 018624 Rev 5Contents1 Overview of the STM32 advanced RTC . . . . . . . . . . . . . . . . . . . . . . . . . . 61.1 RTC cale

Overview of the STM32 advanced RTC AN337120/45 Doc ID 018624 Rev 51.6 RTC reference clock detectionThe reference clock (at 50 Hz or 60 Hz) should have

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 21/451.7 Time-stamp functionThe Time-stamp feature provides the means to automatically sa

Overview of the STM32 advanced RTC AN337122/45 Doc ID 018624 Rev 51.8 RTC tamper detection functionThe RTC includes n tamper detection inputs. The ta

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 23/45Figure 15. Tamper with edge detectionNote: With tamper events, sampling and precharg

Overview of the STM32 advanced RTC AN337124/45 Doc ID 018624 Rev 5Figure 16. Tamper with level detectionUsing the level detection (tamper filter set t

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 25/45 1.8.3 Active time-stamp on tamper detection eventBy setting the TAMPTS bit

Overview of the STM32 advanced RTC AN337126/45 Doc ID 018624 Rev 5The RTC keeps working in reset mode and its registers are only reset by a VDD or VBA

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 27/45Setting 1 Hz as the output signal1. Select LSE “32768 Hz” as the RTC clock source.2.

Overview of the STM32 advanced RTC AN337128/45 Doc ID 018624 Rev 51.11.2 RTC_ALARM outputThe RTC_ALARM output can be connected to the RTC alarm unit A

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 29/45Figure 20. Periodic wakeup routed to RTC_ALARM pinout1.12 RTC security aspects1.12.

AN3371 ContentsDoc ID 018624 Rev 5 3/453.1 Start with the RTC driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333.

Overview of the STM32 advanced RTC AN337130/45 Doc ID 018624 Rev 5calendar year field is set to 0x00 (power-on reset value), meaning that the calendar

AN3371 Advanced RTC featuresDoc ID 018624 Rev 5 31/452 Advanced RTC features Table 15. Advanced RTC featuresRTC features F0 series F3 series

Advanced RTC features AN337132/45 Doc ID 018624 Rev 5Time StampConfigurable input mapping X X X XTimeHours, minutes and secondsXXXXXXSub-seconds X XXX

AN3371 RTC firmware driver APIDoc ID 018624 Rev 5 33/453 RTC firmware driver APIThis driver provides a set of firmware functions to manage the follow

RTC firmware driver API AN337134/45 Doc ID 018624 Rev 5Note: After a reset, the backup domain (RTC registers, RTC backup data registers and backup SRA

AN3371 RTC firmware driver APIDoc ID 018624 Rev 5 35/453.1.4 Outputs configurationThe RTC has two different outputs:● AFO_ALARM, used to manage the RT

RTC firmware driver API AN337136/45 Doc ID 018624 Rev 53.1.8 Backup data registers configurationTo write to the RTC backup data registers, use the RT

AN3371 RTC firmware driver APIDoc ID 018624 Rev 5 37/452Initialization and Configuration RTC_InitInitializes the RTC registers according to the specif

RTC firmware driver API AN337138/45 Doc ID 018624 Rev 54RTC alarms functionsRTC_SetAlarmSets the RTC specified alarm configuration:“Alarm time fields,

AN3371 RTC firmware driver APIDoc ID 018624 Rev 5 39/458RTC digital coarse calibration functionsRTC_DigitalCalibConfigConfigures the coarse calibratio

List of tables AN33714/45 Doc ID 018624 Rev 5List of tablesTable 1. Applicable products and tools. . . . . . . . . . . . . . . . . . . . . . . . . . .

RTC firmware driver API AN337140/45 Doc ID 018624 Rev 511RTC backup registers functionsRTC_WriteBackupRegisterWrites data in a specified RTC backup da

AN3371 Application examplesDoc ID 018624 Rev 5 41/454 Application examplesThe RTC firmware driver is provided with a set of examples, so that you can

Application examples AN337142/45 Doc ID 018624 Rev 5Ta mp er detectionThis example shows how to write/read data to/from RTC backup data registers and

AN3371 Revision historyDoc ID 018624 Rev 5 43/455 Revision history Table 18. Document revision historyDate Revision Changes20-May-2011 1 Initi

Revision history AN337144/45 Doc ID 018624 Rev 524-May-2012 4Updated the title.Added F0 series devices and STM32F0xx in the Introduction.Added a new d

AN3371Doc ID 018624 Rev 5 45/45 Please Read Carefully:Information in this document is provided solely in connection with ST products. STMicro

AN3371 List of figuresDoc ID 018624 Rev 5 5/45List of figuresFigure 1. RTC calendar fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Overview of the STM32 advanced RTC AN33716/45 Doc ID 018624 Rev 51 Overview of the STM32 advanced RTCThe real-time clock (RTC) embedded in STM32 micr

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 7/45the month, day of the week, month and year. This data can be converted to BCD format

Overview of the STM32 advanced RTC AN33718/45 Doc ID 018624 Rev 51.1.2 RTC clock configurationRTC clock sourceThe RTC calendar can be driven by three

AN3371 Overview of the STM32 advanced RTCDoc ID 018624 Rev 5 9/45Figure 5. Prescalers from RTC clock source to calendar unitNote: The length of the sy