PCF2129A Datasheet, PDF (8/68 Pages) NXP Semiconductors – Integrated RTC, TCXO and quartz crystal

NXP Semiconductors
PCF2129A
Integrated RTC, TCXO and quartz crystal
8.2 Control registers
PCF2129A has 28 8-bit registers. The first 3 registers with the addresses 00h, 01h, and
02h are used as control registers.
8.2.1 Register Control_1
Table 5. Control_1 - control and status register 1 (address 00h) bit description
Bit Symbol
Value Description
Reference
7
EXT_TEST 0
[1] _{normal mode}
Section 8.13
1
external clock test mode
6
T
0
[2] _unused
-
5
STOP
0
[1] _{RTC source clock runs}
Section 8.14
1
RTC clock is stopped;
RTC divider chain flip-flops are
asynchronously set logic 0;
CLKOUT at 32.768 kHz, 16.384 kHz, or
8.192 kHz is still available
4
TSF1
0
[1] _{no timestamp interrupt generated}
Section 8.11.1
1
flag set when TS input is driven to an
intermediate level between power supply and
ground;
flag must be cleared to clear interrupt
3
POR_OVRD 0
Power-On Reset Override (PORO) facility
disabled;
Section 8.7.2
set logic 0 for normal operation
1
[1] _{PORO enabled}
2
12_24
0
[1] _{24 hour mode selected}
Table 18
1
12 hour mode selected
1
MI
0
[1] _{minute interrupt disabled}
Section 8.12.1
1
minute interrupt enabled
0
SI
0
[1] _{second interrupt disabled}
1
second interrupt enabled
[1] Default value.
[2] When writing to the register this bit has always to be set logic 0.
PCF2129A_1
Product data sheet
Rev. 01 — 13 January 2010
© NXP B.V. 2010. All rights reserved.
8 of 68