pcf2123 NXP Semiconductors, pcf2123 Datasheet - Page 14

• Manufacturer Part Number: pcf2123
• Description: Spi Real Time Clock/calendar
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF2123_1
Product data sheet
9.6 Time and date function
The majority of the registers are coded in the Binary Coded Decimal (BCD) format. BCD
is used to simplify application use. An example is shown for the Minutes register in
Table
Table 8.
Table 9.
[1]
Table 10.
[1]
Minutes value
(decimal)
00
01
02
:
09
10
:
58
59
Bit
7
6 to 0
Bit
7
6 to 0
Values shown in decimal.
Values shown in decimal.
8.
Symbol
OS
SECONDS
Symbol
-
MINUTES
BCD example
Register Seconds (address 02h) bits description
Register Minutes (address 03h) bits description
Upper-digit
Bit 7
0
0
0
:
0
0
:
0
0
Rev. 01 — 19 November 2008
Bit 6
0
0
0
:
0
0
:
1
1
Value
0
1
00 to 59
Value
-
00 to 59
[1]
[1]
Bit 5
0
0
0
:
0
0
:
0
0
Description
clock integrity is guaranteed
clock integrity is not guaranteed; oscillator has stopped
or been interrupted
this register holds the current seconds coded in BCD
format
Description
unused
this register holds the current minutes coded in BCD
format
Bit 4
0
0
0
:
0
1
:
1
1
Digit
Bit 3
0
0
0
:
1
0
:
1
1
SPI Real time clock/calendar
Bit 2
0
0
0
:
0
0
:
0
0
PCF2123
© NXP B.V. 2008. All rights reserved.
Bit 1
0
0
1
:
0
0
:
0
0
Bit 0
0
1
0
:
1
0
:
0
1
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