DP83907 datasheet(5/70 Pages) NSC

5 / 70 page

20 Pin Description (Continued)

Pin No

Pin Name

Type

Description

NETWORK INTERFACE PINS

44 – 47

TxOda TXOb

TWISTED PAIR TRANSMIT OUTPUTS

These high drive CMOS level outputs are

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

TXOa TXOdb

TPI

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

42 43

RXIa RXIb

TWISTED PAIR RECEIVE INPUTS

These inputs feed a differential amplifier which passes

valid data to the ENDEC module

TPI

33 34

TXb

AUI TRANSMIT OUTPUT

Differential driver which sends the encoded data to the

transceiver

TXa

AUI

36 37

RXb

AUI RECEIVE INPUT

Differential receive input pair from the transceiver

RXa

AUI

38 39

CDb

AUI COLLISION INPUT

Differential collision pair input from the transceiver

CDa

AUI

ACT

led

ACTIVITY

An open-drain active low output It is asserted for approximately 50 ms

whenever the DP83907 transmits or receives data in either AUI or TPI modes

LED

COL

led

COLLISION

An open-drain active low output It is asserted for approximately 50 ms

whenever the DP83907 detects a collision in either either AUI or TPI modes

LED

GDLNK

led

GOOD LINK

An open-drain active low output This pin operates as an output to display link

integrity status if this function has not been disabled by the GDLNK bit in Configuratioin

LED

This output is off if the DP83907 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 DP83907 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

REQ

EQUALIZATION RESISTOR

A resistor can be connected from this pin to GND or VCC to

change the equalization of the TP output

RTX

TRANSMIT LEVEL RESISTOR

A resistor can be connected from this pin to GND or VCC to

change the TP output amplitude level

X1 (OSCIN)

CRYSTAL ON EXTERNAL OSCILLATOR INPUT

XTAL

X2 (OSCOUT)

CRYSTAL FEEDBACK OUTPUT

Used in crystal connections only Should be left

unconnected when using an oscillator module

XTAL

THIN

THIN CABLE

This output is high if DP83907 is configured for thin cable It can be used to

enable the DC-DC converter required by the thin Ethernet configuration

DCDC

Note

Driver Types are I e Input O e Output IO e Bi-directional Output OCH e Open Collector 3ST e TRI-STATE Output TTL e TTL Compatible

AUI e Attachment Unit Interface TPI e Twisted Pair Interface LED e LED Drive MOS e CMOS Level Compatible XTAL e Crystal

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