SMC91C95 Ver la hoja de datos (PDF) - SMSC -> Microchip

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SMC91C95

ISA/PCMCIA Full Duplex Single-Chip Ethernet and Modem Controller with RAM

SMSC -> Microchip 

PIN NO.

26

NAME

20

Modem Ring

Input

21

nModem

Ring Output

A

22

Modem Ring

Output B

14

Speaker

Input

15

Speaker

Output

28

29

DESCRIPTION OF PIN FUNCTIONS

SYMBOL

TYPE

DESCRIPTION

MIDLEN1

O4

Powerdown output to modem controller. This

pin is active (high) when either the PWRDWN

bit (CSR bit 2) is set or the modem is disabled

(not configured).

MRINGIN

I

Ring input from the modem controller.

Toggles when ringing, low when not ringing.

nMRINGOA

O4

Ring output signal. When there is no ringing

on the MRINGIN pin and the modem is not in

Powerdown mode this output is high. During

ringing this signal is the inverse of the

MRINGIN input. When the PWRDWN bit is

set or the function is disabled, this output is

low. This signal is activated about 12 msec

after removing Powerdown.

MRINGOB

O4

Ring output signal. When the modem is not in

Powerdown mode (PWRDWN bit is zero and

the function is enabled) this output follows the

value of the MRINGIN input. When entering

Powerdown mode, a rising edge is generated

on the pin. A rising edge is also generated

when exiting Powerdown mode also. Refer to

Figure 2.

SPKRIN

I with pullup Speaker Input. This is a digitized (single level)

audio input from the modem controller.

SPKROUT

O4 tri-stable

with pullup

Speaker Output. This pin reflects the SPKRIN

pin when enabled by the AUDIO bit (Modem

CSR bit 3). When disabled this pin is tri-

stated.

nMPDOUT

I Schmitt

Used to control Powerdown mode. Tie to a

180K pull-up and a 0.1uF cap to ground.

Tie high when not used. This signal is used

in the RC time constant.

MFBK1

O4 with

pullup

Tie to nMPDOUT through a 5.1M resistor.

This signal is used in the RC time constant

in conjuction with the nMPDOUT pin.

13

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