DP83936AVF datasheet(5/104 Pages) NSC

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20 Pin Description

I e

Input

O e

Output

Z e

TRI-STATE

Input TTL compatible

ECL e Emitter Coupled Logic type drivers for interfacing to

the Attachment Unit Interface

TP e

Totem Pole type drivers These drivers are driven

either high or low and are always driven Drive lev-

els are CMOS compatible

TRI e TRI-STATE drivers These pins are driven high low

or TRI-STATE Drive levels are CMOS compatible

These pins may also be inputs (depending on the

pin)

OC e Open Collector type drivers

These drivers are

TRI-STATE when inactive and are driven low when

active These pins may also be inputs (depending

on the pin)

TPI e Twisted Pair Interface

Pin names which contain a ‘‘’’ indicate dual function pins

TABLE 2-1 Pin Description

Symbol

Driver

Direction

Description

Type

NETWORK INTERFACE PINS

EXT

EXTERNAL ENDEC SELECT

Tying this pin to VCC (EXT e 1) disables the internal

ENDEC and allows an external ENDEC to be used Tying this pin to ground (EXT e 0)

enables the internal ENDEC This pin must be tied either to VCC or ground Note the

alternate pin definitions for CRSoCRSi COLoCOLi RXDoRXDi RXCoRXCi and

TXCoTXCi When EXT e 0 the first pin definition is used and when EXT e 1 the second

pin definition is used

AUITP

ATTACHMENT UNIT INTERFACE (AUI)TWISTED PAIR (TP) SELECT

Tying this pin

to VCC (AUITP e 1) enables the AUI mode for interface with the ENDEC unit Tying this

pin to GND (AUITP e 0) enables the TPI Module mode for interface with the ENDEC

unit

TXOda TXOa

TPI

TWISTED PAIR TRANSMIT OUTPUTS

These high drive CMOS level outputs are

resistively combined external to the chip to produce a differential output signal with

TXOb TXOdb

equalization to compensate for Intersymbol Interference (ISI) on the twisted pair medium

RXIa RXIb

TPI

TWISTED PAIR RECEIVE INPUTS

These inputs feed a differential amplifier which

passes valid data to the ENDEC module

TXLED

TRANSMIT

An active low output It is asserted for approximately 50 ms whenever the

SONIC-T Controller transmits data in either AUI or TPI modes

RXLED

RECEIVE

An active low output It is asserted for approximately 50 ms whenever receive

data is detected in either AUI or TPI mode

COLED

COLLISION

An active low output It is asserted for approximately 50 ms whenever the

SONIC-T Controller detects a collision in either AUI or TPI modes

POLED

POLARITY

An active low output This signal is normally inactive When the TPI module

detects seven consecutive link pulses or three consecutive received packets with

reversed polarity it is asserted

LINKLED

GOOD LINK

An active low output This pin operates as an output to display link integrity

status if this function has not been disabled by the LNKDIS pin described below This

output is off if the SONIC-T Controller is in AUI mode or if link testing is enabled and the

link integrity is bad (ie the twisted pair link has been broken)

This output is on if the SONIC-T Controller is in Twisted Pair Interface (TPI) mode link

integrity checking is enabled and the link integrity is good (ie the twisted pair link has

not been broken) or if the link testing is disabled

LNKDIS

LINK DISABLE

When this pin is tied to GND (LNKDIS e 0) the link test pulse

generation and integrity checking function are both disabled

LOWSQL

LOW SQUELCH SELECT

Tying this pin to VCC (LOWSQL e 1) sets the squelch mode

to use a squelch threshold level lower than that of the 10BASE-T specification (see

Section 31)

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