Epson RX8130CE - Effect of the Digital Offset Function to Other Functions

17. Digital offset function
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ETM50E-07 Seiko Epson Corporation 52
 How to calculate the offset value
1 ) When the offset value is positive:
L [7  1] =[Offset Value]/ 3.05 However, decimals are discarded.
Example calculation: When the offset value is +192

10
-6
L[7  1] = 192.26 / 3.05 = 63 (Dec)
= 0111111(bin) is set.
2 ) When the offset value is negative:
L[7  1] = 128 – [Offset Value] / 3.05 However, decimals are discarded.
Example calculation: When the offset value is 158

10
-6
L[7  1] = 128 - ( 158 / 3.05 ) = 76(Dec) = 1001100(bin) is set.
3 ) When calculate from accuracy of a clock
To adjust 30 seconds in 30 days:
Example calculation: 30sec. / 2592000s (30days) = 11.57

10
-6
Positive offset
L[7  1] = 11.57 / 3.05 = 4 (Dec) However, decimals are discarded.
= 0000100(bin) is set.
Negative offset
L[7  1] = 128 – ( 11.57 / 3.05 ) = 124 (Dec) However, decimals are discarded.
= 1111100(bin) is set.
17.2. Effect of the digital offset function to other functions
Because this function adjusts an internal sub-second clock, this function affects the a Wakeup timer interrupt
function and FOUT function
1) FOUT function
 1 Hz setting: Once in 10 seconds, the 1 Hz period fluctuates.
 1024 Hz setting: Once in 10 seconds, the 1024 Hz period fluctuates.
There are cases where there is no fluctuation, depending on the offset correction value.
 32.768 kHz Not affected.
2) Wakeup timer interrupt function
 64 Hz or 1 Hz source clock setting: Once in 10 seconds, the period fluctuates.
When the timer intervals are long, the fluctuations appear small.
 4096 Hz source clock setting: Not affected.