EM91450 Ver la hoja de datos (PDF) - ELAN Microelectronics

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EM91450

TONE/PULSE DIALER WITH LCD INTERFACE AND I.P.P. DETECT FUNCTION

ELAN Microelectronics 

EM91450 SERIES

TONE/PULSE DIALER WITH LCD INTERFACE

AND I.P.P. DETECT FUNCTION

FUNCTIONAL BLOCK DIAGRAM

COL1

COL2

COL3

COL4/KT

Keyboard

interface

(column)

SDO HFO HDO RMUTE

Output circuit

Row/Column

programming counter

XMUTE

I/O circuit

XIN

XOUT

Oscillator

Memory

Timing/Control circuit

latch

&

decoder

D/A

converter

DTMF

ROW1

Keyboard

interface

Input circuit

Pulse

generator

PO

ROW4

(Row)

VDD

HFI HKS DRING

PIN DESCRIPTIONS

Symbol

ROW1~ROW4

COL1~COL3

COL4/KT

XIN and XOUT

XMUTE

VDD and VSS

HFI

HFO

DTMF

Function

Keyboard scan pins of row group. In idle state (HKS is "High" and HFO is "Low"),

these pins stay ÒHigh impedanceÓ level to prevent power consumption. Otherwise,

these pins switch to ÒHighÓ level for detecting keyboard entry. These pins will output

600 Hz signal while keyboard is scanning.

Keyboard scan pins of column group. In idle state, these pins stay "High impedance"

level. Otherwise these pins switch to ÒLowÓ level for detecting keyboard entry. These

pins will output 600 Hz signal while keyboard is scanning.

The fourth column group pin of the keyboard that also provides the keytone output

. Normally, this pin stays "Low" level for detecting keyboard entry. After a valid

keyboard entry, this pin will output keying confirmation tone that is 600 Hz signal and

30 ms duration. To prevent signal interference, while DTMF issue, it will disable key

tone output except function key.

Oscillator input and output pins. A 3.579545 MHz crystal or ceramic resonator must

be crossed connection to XIN and XOUT pins which generate system clock.

Input/Output structure pin. The output is a open drain structure. Input is schmitt trigger

structure. This pin will be input pin during ON-HOOK status for illegal parallel phone

detect input pin and will be output pin in OFF-HOOK condition for control speech

network.

Positive and negative power supply input pins. Recommended operating voltage from

2.0Vdc to 5.5Vdc.

Handfree inputs pin which accepts falling edge signal to turn "on" or turn "off"

handfree function. This pin is hysteresis input structure and built-in pull up resistor

(typically 200 Kohms).

Handfree outputs pin that is designed to control telephone line for on-hook dialing or

control speakerphone circuit for handfree conversation. When handfree function is

executed, this pin will switch to"High". Otherwise, this pin stays "Low" level.

The DTMF (Dual Tone Multi-Frequency) and music signals output pin. Normally,

this pin stays "Low" level. In Tone dialing mode, this pin will output DTMF signal

that is corresponding to keyboard 0 .. 9, * and # keys.

* This specification are subject to be changed without notice.

2.10.1999 3

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