PCF2127AT/1 NXP [NXP Semiconductors], PCF2127AT/1 Datasheet - Page 6

• Manufacturer Part Number: PCF2127AT/1
• Description: Integrated RTC, TCXO and quartz crystal
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
PCF2127A_2
Product data sheet
8.1 Register overview
The PCF2127A contains 30 8-bit registers (see
address register: the built-in address register will increment automatically after each read
or write of a data byte up to the register 1Bh. After register 1Bh the auto-incrementing will
wrap around to address 00h. The registers 1Ch and 1Dh must be addressed directly (see
Figure
Fig 3.
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The first three registers (memory address 00h, 01h, and 02h) are used as control
registers (see
The memory addresses 03h through to 09h are used as counters for the clock
function (seconds up to years). The date is automatically adjusted for months with
fewer than 31 days, including corrections for leap years. The clock can operate in
12-hour mode with an AM/PM indication or in 24-hour mode (see
Addresses 0Ah through 0Eh define the alarm function. It can be selected that an
interrupt is generated when an alarm event occurs (see
The register 0Fh defines the temperature measurement period and the clock out
mode. The temperature measurement can be selected from every 4 minutes (default)
down to every 30 seconds (see
(default) down to 1 Hz for use as a system clock, a microcontroller clock etc. can be
chosen (see
Address registers 10h and 11h are used for the watchdog and countdown timer
functions. The timer has four selectable source clocks allowing for timer periods from
less than 1 ms to greater than 4 hours (see
the countdown timer can be enabled (see
possible to select whether an interrupt or a pulse on the reset pin will be generated
when the watchdog times out. For the countdown timer it is only possible that an
interrupt will be generated at the end of the countdown.
Address registers 12h to 18h are used for the timestamp function. When the
trigger-event happens the actual time is saved in the timestamp registers (see
Section
Address register 19h is used for the correction of the crystal aging effect (see
Section
3).
Handling address registers
8.12).
8.4.1).
All information provided in this document is subject to legal disclaimers.
address register
Table
Section
1Ch
1Dh
00h
01h
02h
03h
19h
1Ah
1Bh
...
10).
Rev. 02 — 7 May 2010
8.2).
auto-increment
not reachable by auto-inc. - needs to be addressed directly
not reachable by auto-inc. - needs to be addressed directly
Table
wrap around
9). CLKOUT frequencies of 32.768 kHz
Integrated RTC, TCXO and quartz crystal
Section
Table
Table
4) with an auto-incrementing
36). Either the watchdog timer or
8.11). For the watchdog timer it is
Section
001aaj307
PCF2127A
8.10).
Section
© NXP B.V. 2010. All rights reserved.
8.9).
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