s-35399a03 Seiko Instruments Inc., s-35399a03 Datasheet - Page 30

• Manufacturer Part Number: s-35399a03
• Description: 2-wire Real-time Clock
• Manufacturer: Seiko Instruments Inc.

30
2-WIRE REAL-TIME CLOCK
S-35399A03
(1 Hz output)
3. How to confirm setting value for register and result of correction
INT1 pin
The S-35399A03 does not adjust the frequency of the crystal oscillation by using the clock-correction function. Therefore
users cannot confirm if it is corrected or not by measuring output 32.768 kHz. When the function to clock-correction is
being used, the cycle of 1 Hz clock pulse output from the
Figure 31 .
Measure a and b by using the frequency counter
results.
Calculate the error of the clock based on the average frequency (Tave).
confirmation.
Confirmation example: When B0 =0, 66h is set
*1. Use a high-accuracy frequency counter of 7 digits or more.
Caution
B0 = 0, Tave = (a × 19 + b) ÷ 20
B0 = 1, Tave = (a × 59 + b) ÷ 60
Calculating the average frequency allows to confirm the result of correction.
Measurement results: a = 1.000080 Hz, b = 0.998493 Hz
Before correction
After correction
Measure the oscillation frequency under the usage conditions.
Clock Correction Register Setting Value
B0 = 0, a : 19 times, b : Once
B0 = 1, a : 59 times, b : Once
a
00 h (Tave = a)
66 h (Tave = (a × 19 + b) ÷ 20)
Figure 31 Confirmation of Correction Result
a
19 times or 59 times
Seiko Instruments Inc.
*1
. Calculate the average frequency (Tave) based on the measurement
INT
1.000080
Average Frequency [Hz]
1.00000065
1
pin changes once in 20 times or 60 times, as shown in
a
The following shows an example for
Once
86393
Per Day [s]
86399.9
b
Rev.1.0
a
_00