Epson RX-8025SA - Page 17

RX - 8025 SA / NB
Page - 14 ETM10E-04
8.3.3. Adjustment examples
Example 1) Setting time forward
Objective) To adjust (advance) the clock precision when FOUT clock output is 32767.7 Hz
(1) Determine the current amount of variance
32767.7 Hz → (32767.7 − 32768) / 32768 ∗ [ 32768 ] = Reference values
→ −9.16 × 10
−
6
(2) Calculate the optimum adjustment data (decimal value) relative to the current variance.
Adjustment data = variance / adjustment resolution
= −9.16 / 3.05
≈ −3 (decimal values are rounded down from 4 and up from 5)
∗ For adjusting forward from a retarded variance, this formula can be corrected using reciprocal numbers, but since this
product inverts the +/- attributes, this formula can be used as it is.
(3) Calculate the setting adjustment data (hexadecimal)
To calculate the setting adjustment data while taking 7-bit binary encoding into account,
subtract the adjustment data (decimal) from 128 (80h).
Setting adjustment data = 128 − 3 = 125 (decimal)
= 80h − 03h = 7Dh (hexadecimal)
Example 2) Setting time backward
Objective) To adjust (set back) the clock precision when FOUT clock output is 32768.3 Hz
(1) Determine the current amount of variance
32768.3 Hz → (32768.3 − 32768) / 32768 ∗ [ 32768 ] = reference values
→ +9.16 × 10
−
6
(2) Calculate the optimum adjustment data (decimal value) relative to the current variance.
Adjustment data = (variance / adjustment resolution) + 1
= (+9.16 / 3.05) + 1 ∗ Add 1 since reference value is 01h
≈ +4 (decimal values are rounded down from 4 and up from 5)
∗ For adjusting backward from an advanced variance, this formula can be corrected using reciprocal numbers, but
since this product inverts the +/- attributes, this formula can be used as it is.
(3) Calculate the setting adjustment data (hexadecimal)
The value "4" can be used in hexadecimal as it is (04h).
Setting adjustment data = 04 h (hexadecimal)