SC9302F datasheet(9/39 Pages) SILAN

9 / 39 page

Silan

Semiconductors

SC9302 Series

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 2.0

2001-11-01

PIN DESCRIPTION

Pin Name

I/O

Internal

Connection

Description

C ~ 4

R ~ 4

I/O

CMOS

IN/OUT

These pins construct a 4x4 keyboard matrix to perform the keyboard

input detecting and dialing specification setting functions, when on-hook

(

HKS =high) all the pins are set to high. While off-hook the column

group (

C ~ 4

C ) stays low and the row group (

R ~ 4

R ) is set to high

for key input detecting.

An inexpensive single contact 4x4 keyboard can be an input device.

Pressing a key connects a single column to a single row, and actuates

the system oscillator to result in a dialing signal output. If more than two

keys are pressed at the same time, no response can be brought about.

The key-in debounce time is 20ms. Refer to the keyboard table for

keyboard arrangement and to the functional description for dialing

specification selection.

OSCILLATOR

The system oscillator consists of an inverter, a bias resistor and the

necessary load capacitor on chip. Connecting a standard 3.579545MHz

crystal or ceramic resonator to X1 and X2 terminals can implement the

oscillator function. The oscillator is turned off in the stand-by mode, and

is actuated whenever a keyboard entry is detected.

XMUTE

NMOS OUT

The

XMUTE is an NMOS open drain structure pulled to VSS during

dialing signal transmitting. Otherwise, it is an open circuit. The

XMUTE is used to mute the speech circuit when transmitting the dial

signal.

HKS

CMOS IN

This pin is used to monitor the status of the hook-switch and its

combination with HFI/

HDI can control the PO pin output to make or

break the line.

HKS =VDD: On-hook state ( PO =low). Except HFI/

HDI (hand-free

/ hold-line control input), other functions are all disabled.

HKS =VSS: Off-hook state ( PO =high). The chip is in the stand-by

mode and ready to receive the key input.

(to be continued)

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