RV-8523 Datasheet, PDF (17/57 Pages) MICORO CRYSTAL SWITZERLAND – Real Time Clock

Micro Crystal
Real Time Clock / Calendar Module
RV-8523
8.5.1.FREQUENCY OFFSET (address 0Eh…bits description)
Address
0Eh
Function
Frequency Offset
Bit 7
MODE
Bit 6
Bit 5
Offset value
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit
7
6 to 0
Symbol
MODE
Offset
Value
0¹⁾
1
+63/-64
Description
Offset is made once every two hours
Offset is made once every minute
Offset value (see table below)
1) _{Default value.}
For MODE = 0, each LSB introduces an offset of 4.34 ppm. For MODE = 1, each LSB introduces an offset of 4.069
ppm. The values of 4.34 ppm and 4.069 ppm are based on a nominal 32.768 kHz clock. The offset value is coded
in two’s complement giving a range of +63 LSB to -64 LSB.
Offset [6:0]
0111111
0111110
:
0000010
0000001
0000000
1111111
1111110
:
1000001
1000000
Offset value in decimal
+63
+62
:
+2
+1
0¹⁾
-1
-2
:
-63
-64
Offset value in ppm
Every two hours (MODE = 0)
+273.420
+269.080
:
+8.680
+4.340
0¹⁾
-4.340
-8.680
:
-273.420
-277.760
Every minute (MODE = 1)
+256.347
+252.278
:
+8.138
+4.069
0¹⁾
-4.069
-8.138
:
-256.347
-260.416
1) _{Default value.}
The correction is made by adding or subtracting clock correction pulses, thereby changing the period of a single
second.
It is possible to monitor when correction pulses are applied. To enable correction interrupt generation, bit CIE
(register Control 1) has to be set logic 1. At every correction cycle a ¹/₄₀₉₆ s pulse is generated on pin INT_x . If
multiple correction pulses are applied, a ¹/₄₀₉₆ s interrupt pulse is generated for each correction pulse applied.
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