UPD4990AC データシートの表示（PDF） - NEC => Renesas Technology

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UPD4990AC

SERIAL I/O CALENDAR & CLOCK CMOS LSI

NEC => Renesas Technology 

µPD4990A

FUNCTION SPECIFICATIONS

• Crystal frequency (X tal osc.).

° 32.768 kHz

• Data

Data types are: second, minute, day, week, month, and year.

Leap years, 31-day months, and months with 30 or less days are adjusted automatically.

A 24-hour system is used and last two digits of Gregorian year are indicated.

It is assumed that leap years are expressed by multiples of 4.

• Data format

Data is represented in BCD notation. Only months are represented in hexadecimal notation.

• Data input-output and Clock

Data is input/output synchronously with reference to the external clocks input from the CLK pin using the serial

input/output system. (See Fig. 1.)

• Timing pulse output

Three frequencies, 64 Hz, 256 Hz, and 2 048 Hz, can be set with C0, C1 and C2 pins.

Using serial data input command, selective timing pulses (TPs) are 64 Hz, 256 Hz, 2 048 Hz, and 4 096 Hz

and selective output intervals are 1, 10, 30, and 60 seconds.

• Function mode selection

A function mode can be selected by the inputs from C0, C1, and C2. Also a function mode can be selected through

serial data input. (C0 = C1 = C2 = VDD)

Each command is latched with STB (strobe).

• Chip select

Connecting the CS pin to the ground level inhibits CLK and STB inputs.

• Data output inhibition

Connecting the OUT ENBL pin to the ground level sets the DATA OUT pin at high impedance.

command

register

Figure 1.

MSB

LSB

Ten's of Unit of

year year

month

day of Ten's of

the week days

Unit of

days

Ten's of

hours

Unit of

hours

Ten's of Unit of Ten's of Unit of

minutes minutes seconds seconds

C3' C2' C1' C0'

D3 D2 D1 D0

52 Bit Shift Register

* DATA of 52 Bit Shift Register appears on DATA OUT terminal from LSB of second.

4

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