3-WIRE REAL-TIME CLOCK
S-35190A
Rev.2.4_00
Pin Function
•
CS (input for chip select) pin
This pin is to input chip select, has a pull-down resistor. Communication is available when this pin is in “H” level. If not
using communication, set this pin “L” or open.
•
SCK (input for serial clock) pin
This pin is to input a clock pulse for serial interface. When the CS pin is in “H”, the SIO pin inputs/outputs data by
synchronizing with the clock pulse. When the CS pin is in “L” or open, the SCK pin does not accept inputting a clock
pulse.
•
SIO (I/O for serial data) pin
This pin is to data input/output for serial interface. When the CS pin is in “H”, the SIO pin inputs/outputs data by
synchronizing with a clock pulse from the SCK pin. The status is in high impedance when the CS pin is in “L” or open,
so that the S-35190A does not transmit data. Setting the CS pin to “H” level from “L” or open, this SIO pin goes in the
input status so that it receives the command data. This pin has CMOS input and Nch open drain output.
•
•
XIN, XOUT (crystal oscillator connect) pin
Connect a crystal oscillator between XIN and XOUT.
INT (output for interrupt signal) pin
This pin outputs a signal of interrupt, or a clock pulse. By using the status register 2, users can select either of; alarm 1
interrupt, alarm 2 interrupt, output of user-set frequency, per-minute edge interrupt, minute-periodical interrupt 1,
minute-periodical interrupt 2, or 32.768 kHz output. This pin has Nch open drain output.
•
•
VDD (positive power supply) pin
Connect this VDD pin with a positive power supply. Regarding the values of voltage to be applied, refer to “
Recommended Operation Conditions”.
VSS pin
Connect the VSS pin to GND.
Equivalent Circuits of I/O Pin
SIO
SCK
Figure 4 SCK pin
Figure 5 SIO pin
CS
INT
Figure 7 INT pin
Figure 6 CS pin
Seiko Instruments Inc.
3
SII [ SEIKO INSTRUMENTS INC ]
