PCF2127ATSLASH1 datasheet(47/80 Pages) NXP

47 / 80 page

PCF2127A_2

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Product data sheet

Rev. 02 — 7 May 2010

47 of 80

NXP Semiconductors

PCF2127A

Integrated RTC, TCXO and quartz crystal

The pulse generator for the minute/second interrupt operates from an internal 64 Hz clock

and generates a pulse of 1

⁄

64 seconds in duration.

8.13.2 Countdown timer interrupts

The generation of interrupts from the countdown timer is controlled via the CDTIE bit

(register Control_2).

The interrupt may be generated as a pulsed signal at every countdown period or as a

permanently active signal which follows the status of the countdown timer flag CDTF. Bit

TI_TP is used to control this bit.

In this example, bit TI_TP is logic 1 and the MSF flag is not cleared after an interrupt.

Fig 26. INT example for SI and MI when TI_TP is logic 1

In this example, bit TI_TP is logic 0 and the MSF flag is cleared after an interrupt.

Fig 27. INT example for SI and MI when TI_TP is logic 0

001aaf905

seconds counter

minutes counter

INT when SI enabled

MSF when SI enabled

INT when only MI enabled

MSF when only MI enabled

001aag072

seconds counter

minutes counter

INT when SI enable

MSF when SI enable

INT when only MI enabled

MSF when only MI enabled

PCF2127AT/1 Datasheet(PDF) 47 Page - NXP Semiconductors