PCA2125_00

© NXP B.V. 2007. All rights reserved.

Preliminary data sheet

Rev. 00.11 — 30 January 2007

6 of 40

NXP Semiconductors

PCA2125

SPI Real time clock / calendar

6.1 Register overview

16 registers are available. The time registers are encoded in the binary coded decimal

format (BCD) to simplify application use. Other registers are either bit-wise or standard

binary.

Table 5:

Registers overview

Bit positions labelled as x are not implemented and will return a 0 when read. Bit positions labelled with 0 should always be

written with logic 0.

Address

Register name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

control 1

ext test

0

stop

0

POR ovrd

12/24

0

0

control 2

MI

SI

MSF

TI/TP

AF

TF

AIE

TIE

seconds

RF

10 seconds

seconds

minutes

x

10 minutes

minutes

hours

x

x

AMPM / 10 hours

hours

days

x

x

10 days

days

weekdays

x

x

x

x

x

weekdays

months

x

x

x

10months

months

years

10 years

years

minute alarm

AEn

10 minute alarm

minute alarm

hour alarm

AEn

x

AMPM / 10 hour

alarm

hour alarm

day alarm

AEn

x

10 day alarm

day alarm

weekday alarm

AEn

x

x

x

x

weekday alarm

CLKOUT control

x

x

x

x

x

COF2

COF1

COF0

timer control

TE

x

x

x

x

x

CTD1

CTD0

countdown timer

countdown timer value, n