pcf2123 NXP Semiconductors, pcf2123 Datasheet - Page 29

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

NXP Semiconductors
PCF2123_1
Product data sheet
Table 36.
[1]
The correction is made by adding or subtracting 64 Hz clock correction pulses, thereby
changing the period of a single second.
Table 37.
In normal mode, the correction is triggered once per two hours and then correction pulses
are applied once per minute until the programmed correction values has been implement.
In course mode, the correction is triggered once per hour and then correction pulses are
applied once per minute up to a maximum of 60 minutes. When correction values greater
than 60 are used, additional correction pulses are made in the 59th minute (see
OFFSET[6:0]
0 1 1 1 1 1 1
0 1 1 1 1 1 0
0 0 0 0 0 1 0
0 0 0 0 0 0 1
0 0 0 0 0 0 0
1 1 1 1 1 1 1
1 1 1 1 1 1 0
1 0 0 0 0 0 1
1 0 0 0 0 0 0
Offset in ppm
2.17
4.34
Default mode.
:
:
Register Offset_register
Example of converting the offset in ppm to seconds
Seconds per
Day
0.187
0.375
Rev. 01 — 19 November 2008
Offset value in
decimal
+63
+62
:
+2
+1
0
:
[1]
1
2
63
64
Week
1.31
2.62
Offset value in ppm
Normal mode
MODE = 0
+136.71
+134.54
:
+4.34
+2.17
0
:
2.17
4.34
136.71
138.88
Month
5.69
11.4
SPI Real time clock/calendar
Course mode
MODE = 1
+273.42
+269.08
:
+8.68
+4.34
0
:
4.34
8.68
273.42
277.76
PCF2123
© NXP B.V. 2008. All rights reserved.
Year
68.2
136
Table
29 of 54
38).