pcf2127a NXP Semiconductors, pcf2127a Datasheet - Page 9

• Manufacturer Part Number: pcf2127a
• Description: Integrated Rtc, Tcxo And Quartz Crystal
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF2127A_1
Product data sheet
8.2.1 Register Control_1
8.2 Control registers
PCF2127A has 30 8-bit registers. The first 3 registers with the addresses 00h, 01h and
02h are used as control registers.
Table 5.
[1]
[2]
Bit
7
6
5
4
3
2
1
0
Default value.
When writing to the register this bit has always to be set logic 0.
Symbol
EXT_TEST
T
STOP
TSF1
POR_OVRD
12_24
MI
SI
Control_1 - control and status register 1 (address 00h) bit description
Rev. 01 — 21 January 2010
Value
0
1
0
0
1
0
1
0
1
0
1
0
1
0
1
[1]
[2]
[1]
[1]
[1]
[1]
[1]
[1]
Description
normal mode
external clock test mode
unused
RTC source clock runs
RTC clock is stopped;
no timestamp interrupt generated
flag set when TS input is driven to an
intermediate level between power supply
and ground;
Power-On Reset Override (PORO) facility
disabled;
PORO enabled
24 hour mode selected
12 hour mode selected
minute interrupt disabled
minute interrupt enabled
second interrupt disabled
second interrupt enabled
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
flag must be cleared to clear interrupt
set logic 0 for normal operation
Integrated RTC, TCXO and quartz crystal
PCF2127A
© NXP B.V. 2010. All rights reserved.
Reference
Section 8.14
Section 8.15
Section 8.12.1
Section 8.7.2
Table 22
Section 8.13.1
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