W91472N 查看數據表（PDF） - Winbond

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W91472N

6-MEMORY TONE/PULSE DIALER WITH SAVE AND HANDFREE FUNCTIONS

Winbond 

W91472N SERIES

Pin Description, continued

SYMBOL 18-PIN

HFI ,

-

HFO

20-PIN

10, 11

I/O

FUNCTION

I, O Handfree control pins.

A low pulse on the HFI input pin toggles the handfree

control state.

Status of the handfree control state is listed in the

following table:

CURRENT STATE

HOOK SW.

HFO

INPUT

NEXT STATE

HFO DIALING

-

Low HFI

High

Yes

On Hook

High HFI

Low

No

Off Hook

High HFI

Low

Yes

On Hook

-

Off Hook Low

Yes

Off Hook

Low On Hook Low

No

Off Hook

High On Hook High

Yes

HFI pin is pulled to VDD by an internal resistor.

Detailed timing diagram is shown in Figure 3.

BLOCK DIAGRAM

HKS

HFI

XT XT

SYSTEM CLOCK

GENERATOR

ROW

(R1 to R4, Vx)

COLUMN

(C1 to C5)

KEYBOARD

INTERFACE

DTMF

D/A

CONVERTER

READ/WRITE

COUNTER

CONTROL

LOGIC

LOCATION

LATCH

RAM

PULSE

CONTROL

LOGIC

ROW & COLUMN

PROGRAMMABLE

COUNTER

DATA LATCH

& DECODER

MODE

T/P MUTE

DP/C6

HFO

-4-

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