3-WIRE REAL-TIME CLOCK
S-35190A
Rev.2.4_00
6. Operation of power-on detection circuit
When power is applied to the S-35190A, the power-on detection operates to set “1” in the POC flag (B0 in the status
register 1). A 1 Hz clock pulse is output from the INT pin.
Status register 2 setting
32kE = 0, INT1AE = INT1ME = 0,
INT1FE
Change by reset command
OFF
INT pin
0.5 s 0.5 s
Figure 32 Output Timing of INT Pin during Operation of Power-on Detection Circuit
Function to Clock-Correction
The function to clock-correction is to correct advance/delay of the clock due to the deviation of oscillation frequency, in
order to make a high precise clock. For correction, the S-35190A adjusts the clock pulse by using a certain part of the
dividing circuit, not adjusting the frequency of the crystal oscillator. Correction is performed once every 20 seconds (or 60
seconds). The minimum resolution is approx. 3 ppm (or approx. 1 ppm) and the S-35190A corrects in the range of −195.3 to
+192.2 ppm (or of −65.1 to +64.1 ppm). (Refer to Table 12.) Users can set up this function by using the clock-correction
register. Regarding how to calculate the setting data, refer to “1. How to calculate”. When not using this function, be sure
to set “00h”.
Table 12 Function to Clock-Correction
B0 = 0
B0 = 1
Correction
Minimum resolution
Correction range
Every 20 seconds
3.052 ppm
−195.3 to +192.2 ppm
Every 60 seconds
1.017 ppm
−65.1 to +64.1 ppm
26
Seiko Instruments Inc.
SII [ SEIKO INSTRUMENTS INC ]
