17. Digital offset function
RX8130CE
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ETM50E-07
Seiko Epson Corporation
51
17. Digital offset function
With this function it is possible to increase or decrease the speed of the time counting and thus put a positive
or negative offset to the clock precision. The adjustment range for this offset correction is +192.3
10
-6
to -
195.3
10
-6
in steps of 3.05
10
-6.
17.1.Digital offset register
Address
h
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
30
Digital offset
DTE
L7
L6
L5
L4
L3
L2
L1
DTE=”1” enables the digital offset function.
When the digital offset function is enabled, the digital offset register digitally offsets the sub-second clocks
according to the values set in the digital offset register. This correction of the second time register occurs every
10 seconds and the level of correction depends on the offset required.
When outputting a 32.768 kHz signal on
FOUT-pin , this function has no influence, since the oscillation frequency of the built-in crystal does not change
by using this function. In case of outputting a 1 Hz or 1024 Hz signal on FOUT, the offset correction will cause a
certain jitter on the clock signal.
Alarm function as well as the Wakeup Timer function (if source clock lower than 4096 Hz is selected) are affected
by this function.
In order to disable the digital offset function, set to DTE = ”0”. In this case the L1 to L7 are ignored.
Below table shows the relationship of the L7
L1 bit and the digital offset value
When the L7 bit = “0”, the offset is positive (clock runs faster), when the L7 bit = “1”, the offset is negative (the
clock runs slower).
Table 45 Digital Adjustment
Digital offset bits
Offset value
(
10
-6
)
L7
L6
L5
L4
L3
L2
L1
0
1
1
1
1
1
1
+192.26
0
1
1
1
1
1
0
+189.21
0
0
0
0
0
1
0
+6.10
0
0
0
0
0
0
1
+3.05
0
0
0
0
0
0
0
0.00
1
1
1
1
1
1
1
3.05
1
1
1
1
1
1
0
6.10
1
0
0
0
0
0
1
192.26
1
0
0
0
0
0
0
195.31
The offset value is calculated on basis of a shift of the built-in crystal frequency.
