PCF8523 datasheet(18/66 Pages) NXP

номер детали	PCF8523

подробное описание детали	Real-Time Clock (RTC) and calendar

PDF	66 Pages

Scroll/Zoom	100%

производитель	NXP [NXP Semiconductors]

домашняя страница	http://www.nxp.com

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18 / 66 page

PCF8523

All information provided in this document is subject to legal disclaimers.

Product data sheet

Rev. 3 — 30 March 2011

18 of 66

NXP Semiconductors

PCF8523

Real-Time Clock (RTC) and calendar

An unreliable battery will not ensure data integrity during periods of backup battery

operation.

When VBAT drops below the threshold value Vth(bat)low, the following sequence occurs (see

Figure 11):

1. The battery low flag BLF is set logic 1.

2. An interrupt is generated if the control bit BLIE (register Control_3) is enabled. The

interrupt remains active until the battery is replaced (BLF set logic 0) or when bit BLIE

is disabled (BLIE set logic 0).

3. The flag BLF (register Control_3) remains logic 1 until the battery is replaced. BLF

cannot be cleared using the interface. It is cleared automatically by the battery low

detection circuit when the battery is replaced.

Fig 11. Battery low detection behavior with bit BLIE set logic 1 (enabled)

013aaa323

internal power supply (= VBBS)

VBAT

BLF

Vth(bat)low

(= 2.5 V)

VBAT

VDD = VBBS

INT1

PCF8523 датащи(PDF) 18 Page - NXP Semiconductors