AN3371 datasheet(21/45 Pages) STMICROELECTRONICS

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AN3371

Overview of the STM32 advanced RTC

Doc ID 018624 Rev 5

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1.7

Time-stamp function

The Time-stamp feature provides the means to automatically save the current calendar.

Figure 14. Time-stamp event procedure

Provided that the time-stamp function is enabled, the calendar is saved in the time-stamp

registers (RTC_TSTR, RTC_TSDR, RTC_TSSSR) when a time-stamp event is detected on

the pin that the TIMESTAMP alternate function is mapped to. When a time-stamp event

occurs, the time-stamp flag bit (TSF) in RTC_ISR register is set.

Note:

The time-stamp sub-second register is not available for all products. Please refer to

Table 15: Advanced RTC features.

TIME

(RTC_TR)

MS19532V1

Date

Week

date

Month

Year

DATE

(RTC_DR)

Sub-second

(RTC_SSR)

12h or 24h

format

Calendar Unit

TIME

(RTC_TSTR)

Date

Week

date

Month

Year

DATE

(RTC_TSDR)

Sub-second

(RTC_TSSSR)

Copy:

RTC_TSTR = RTC_TR

RTC_TSDR = RTC_DR

RTC_TSSSR = RTC_SSR

On Time- Stamp

event

Table 11.

Time-stamp features

What to do

How to do it

Comments

Enable Time-stamp

Setting the TSE bit of

RTC_CR register to 1

Map TIMESTAMP pin

alternate function

Selecting with TSINSEL bit

in RTC_TCR register

Only for F2 series devices.

The TIMESTAMP pin can be either PI8

or PC13.

Detect a time-stamp event by

interrupt

Setting the TSIE bit in the

RTC_CR register

An interrupt is generated when a time-

stamp event occurs.

Detect a time-stamp event by

polling

By polling on the time-

stamp flag (TSF(1)) in the

RTC_ISR register

To clear the flag, write zero on the TSF

bit.(2)

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