HT93214 datasheet(6/16 Pages) HOLTEK

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HT93214 Series

Rev. 1.10

October 2, 2002

Functional Description

Keyboard matrix

C1~C3, HKS and R1~R4 form a keyboard matrix. To-

gether with a standard 4

´4 keyboard, the keyboard

matrix is used for dialing entries. The keyboard ar-

rangement of the HT93214 series is shown in the Key-

board Information.

Tone frequency

Tone

Name

Output Frequency (Hz)

% Error

Specified

Actual

697

699

+0.29%

770

766

-0.52%

852

847

-0.59%

941

948

+0.74%

1209

1215

+0.50%

1336

1332

-0.30%

1477

1472

-0.34%

Note: % Error does not contain the crystal frequency

drift

Dialing specification selection

· The specifications are selected by the MODE pin.

MODE

Tone/Pulse

Dial Rate

M/B Ratio

VDD

Pulse

10pps

1/2

VSS

Tone

¾¾

Floating

Pulse

20pps

1/2

· The MODE pin status is checked whenever a digit key

is pressed, however the M/B and pulse rate are deter-

mined at the first key entry.

Hand-free function operation

· When HFO is low, a falling edge triggers the HFI,en-

abling the Hand-free function (HFO becomes high).

· Reset Hand-free function

When HFO is high, the Hand-free function is enabled

and can be reset by:

¨ Off-hook

¨ Applying a falling edge to HFI

· Hand-free function table

Current State

Next State

Hook SW

HFO

Input

HFO

Dialing?

Low

HFI

High

Yes

On-hook

High

HFI

Low

Off-hook

High

HFI

Low

Yes

On-hook

off-hook

Low

Yes

Off-hook

Low

on-hook

Low

Off-hook

High

on-hook

High

Yes

Flash

Two flash keys are provided, namely F1, F2 for both se-

ries. All the flash key function as control key with differ-

ent break duration. Whenever a flash key is pressed the

PO pin will be forced low for a TF duration and the trans-

mission of the new digit key inputs will be further de-

layed for a TFP after TF. See the following table for flash

duration selection.

Item

HT93214

300ms

600ms

Key definition

· 0,1,2,3,4,5,6,7,8,9 keys

These are dialing number input keys for both the

pulse mode and the tone mode operation.

· */T

This key executes the P

®T function and waits a TP®T

duration in the pulse mode. On the other hand, the

*/T

key executes the

* function in the tone mode. The */T

key will occupy one memory digit in either tone or

pulse mode.

· #

This is a dialing signal key for the tone mode only, no

response in the pulse mode.

· F1, F2

Pressing one of the flash keys will force the PO pin to

become low for the TF duration. To transmit the dial

signals of the key input that are entered after the F

key, a wait period TFP (sec) after PO pin returns from

low is provided.

· P

Pause key. The execution of this key pauses the out-

put for the TP duration (2.2s).

· R

Redial key. It executes redialing as well as one-key re-

dial function.

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