W91542AN Ver la hoja de datos (PDF) - Winbond

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Fabricante

W91542AN

10-MEMORY TONE/PULSE DIALER WITH SAVE, KEYTONE, LOCK, AND HANDFREE FUNCTIONS

Winbond 

W91540N SERIES

Pin Description, continued

SYMBOL

18-PIN

MODE

13

HKS

10

KT

LOCK

5

(except for

W91541LN)

5

(only for

W91541LN)

DP / C5

11

20-PIN

15

12

5

(except for

W91541ALN)

5

(only for

W91541ALN)

13

I/O

FUNCTION

I Pulling mode pin to VSS places dialer in tone

mode.

Pulling mode pin to VDD places dialer in pulse

mode with M/B ratio of 40:60 (10 ppS, except for

W91542N/542AN is 20 ppS).

Leaving mode pin floating places dialer in pulse

mode with M/B ratio of 33.3:66.7 (10 ppS, except

for W91542N/542AN is 20 ppS).

I The HKS (hook switch) input is used to sense

whether the handset is on-hook or off-hook.

On-hook state, HKS = 1: chip is in sleeping

mode, no operation.

Off-hook state, HKS = 0: chip is enabled for

normal operation.

HKS pin is pulled to VDD by an internal resistor.

O The key tone output is a conventional CMOS

inverter. The key tone is generated when any

valid key is pressed; the KT pin generates a 1.2

KHz square wave at 35 mS. When no key is

pressed, the KT pin remains in low state.

I The function of this terminal is to prevent "0"

dialing and "9" dialing under PABX system long

distance call control. When the first key input

after reset is 0 or 9, all key inputs, including the 0

or 9 key, become invalid and the chip generates

no output. The telephone is reinitialized by a

reset.

The function of the LOCK pin is shown below:

LOCK PIN

FUNCTION

VDD

"0", "9" dialing inhibited

Floating

Normal dialing

VSS

"0" dialing inhibited

O N-channel open drain dialing pulse output.

Flash key will cause DP to be active in either

tone mode or pulse mode.

In lock mode, DP remains low for 300 mS during

off-hook delay time.

The timing diagram for pulse mode is shown in

Figure 1(a, b, c, d).

-4-

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