PCF2131 datasheet(44/86 Pages) NXP

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NXP Semiconductors

PCF2131

Nano-power highly accurate RTC with integrated quartz crystal

Bits labeled as T are unused and return 0 when read.

Bit

Symbol

Value

Place value Description

7 to 5

000

unused

0 to 1

ten’s place

3 to 0

MONTH_TIMESTP

0 to 9

unit place

month timestamp information coded in BCD format

Table 75. Mon_timestp1/2/3/4 - month timestamp register (address 19h/20h/27h/2Eh) bit description

7.12.3.7 Register Year_timestp

Bit

Symbol

YEAR_TIMESTP (0 to 99)

Reset

value

Table 76. Year_timestp1/2/3/4 - year timestamp register (address 1Ah/21h/28h/2Fh) bit allocation

Bit

Symbol

Value

Place value Description

7 to 4

0 to 9

ten’s place

3 to 0

YEAR_TIMESTP

0 to 9

unit place

year timestamp information coded in BCD format

Table 77. Year_timestp1/2/3/4 - year timestamp register (address 1Ah/21h/28h/2Fh) bit description

7.12.4 Dependency between Battery switch-over and timestamp

The timestamp function depends on the control bit BTSE in register Control_3:

BTSE

Description

[1] the battery switch-over does not affect the

timestamp registers

If a battery switch-over event occurs:

[1]

the timestamp 4 group registers store the

time and date when the switch-over occurs;

after this event occurred BF is set logic 1

the timestamp 4 group registers are not

modified;

in this condition subsequent battery switch-

over events or falling edges on pin TS4 are

not registered

Table 78. Battery switch-over and timestamp

[1]

Default value.

7.13 Interrupt output, INTA/INTB

PCF2131 has two interrupt output pins INTA and INTB which are open-drain, active LOW

(requiring a pull-up resistor if used). Interrupts may be sourced from different places:

• second or minute timer

• watchdog timer

PCF2131

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

Product data sheet

Rev. 1.0 — 28 May 2021

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