SM8577B

NIPPON PRECISION CIRCUITS—2

BLOCK DIAGRAM

PIN DESCRIPTION

Number

Name

I/O

Description

1CE

I

Chip enable.With pull-down resistor built-in.

HIGH: Enable

LOW: DATA goes high impedance; input on CLK and DATA stops; and the TM bit is cleared.

2

DATA

I/O

Data read and write input/output

3

CLK

I

Serial clock input.

Data is input (write mode) and output (read mode) on the rising edge of CLK.

4

FOUT

O

Frequency output (controlled by the 4th data bit of the ‘week’ data, FSEL).

1 Hz output when FSEL is 0, and 32.768 kHz output when FSEL is 1.

In 1 Hz output mode, the 1 Hz signal is synchronized to the internal 1 second signal.

FOUT output is not affected by the CE signal.

5

VSS

–

Ground

6

XT

I

Crystal oscillator element connection pin

7

XTN

O

8

VDD

–

Supply voltage.

Connect a

≥ 0.1 µF capacitor between VDD and VSS.

OSC

Divider

Timer Counter

Shift Register

Voltage

Detect

I/O

Controller

Controll

Circuit

DATA

CLK

CE

Output

Controller

FOUT

XT

XTN

VDD

VSS