¡ Semiconductor

MSM58321

15

8

Name

Pin No.

Description

Data input/output pins. (Bidirectional bus). The output is a open-drain type and

4.7 k

Ω ~ 10 kΩ pull-up registers are required utilize these pins as output pins.

Ground pin.

bus pins to the ADDRESS LATCH inside the IC; it is activated when it is at the H

level. This input is activated by the level, not by the edge. Figure 3 shows the

ADDRESS LATCH input/output.

BUSY pin outputs the IC operation state. It is N-channel MOSFET open-drain

output. An external pull-up resistor of 4.6 k

Ω or more must be connected (see

Figure 4) to use the BUSY output. The signals are output in negative logics. If

the oscillator oscillates at 32.768 kHz, the frequency is always 1 Hz regardless of

the CS1 and CS2 unless the D output of the ADDRESS DECODER inside the IC

is H (CODE = H•L•H•H) and CS1 = CS2 = WRITE = H.

Figure 5 shows the BUSY output time chart.

427 µs

BUSY

1 Hz (inside IC)

The counter inside the IC

starts counting at the

1 Hz signal leading edge.

244 µs

122 µs 61 µs

Read/write-inhibited period

1 sec

Figure 5

BUSY

1 Hz (inside IC)

GND

ADDRESS

WRITE

BUSY

9

4 ~ 7

10

ADDRESS WRITE

L

LATCH output

ADDRESS LATCH

(inside IC)

Figure 3

(peripheral circuit power)

4.7 k

Ω or more

+5V

BUSY

N

RESET

WRITE

MSM58321RS

D

BUSY

Figure 4