DESCRIPTION OF PIN FUNCTIONS

PIN NO.

NAME

SYMBOL

TYPE

DESCRIPTION

 

 

 

 

 

10

nReceive

nRXLED

OD16

Internal ENDEC - Receive LED output.

 

LED

 

 

 

 

Receive

RXCLK

I with pullup

External ENDEC - Receive clock input.

 

Clock

 

 

 

 

 

 

 

 

11

nLink LED

nLNKLED

OD16

Internal ENDEC - Link LED output.

 

 

 

 

 

 

Transmit

TXD

0162

External ENDEC - Transmit Data output.

 

Data

 

 

 

 

 

 

 

 

111

Enable

ENEEP

I with pullup

Input. This active high input enables the

 

EEPROM

 

 

EEPROM to be read or written by the

 

 

 

 

SMC91C95. Internally pulled up. Must be

 

 

 

 

connected to ground if no serial EEPROM is

 

 

 

 

used. In PCMCIA mode, a parallel EEPROM

 

 

 

 

is required if no serial EEPROM is used.

 

 

 

 

 

115

nEnable 16

nEN16

I with pullup

Input. When low the SMC91C95 is configured

 

Bit

 

 

for 16 bit bus operation. If left open the

 

 

 

 

SMC91C95 works in 8 bit bus mode. 16 bit

 

 

 

 

configuration can also be programmed via

 

 

 

 

serial EEPROM (In ISA Mode only) or via

 

 

 

 

software initialization of the CONFIGURATION

 

 

 

 

REGISTER.

 

 

 

 

 

101

Crystal 1

XTAL1

Iclk

An external parallel resonance 20 MHz crystal

102

Crystal 2

XTAL2

 

should be connected across these pins. If an

 

external clock source is used, it should be

 

 

 

 

 

 

 

 

connected to XTAL1 and XTAL2 should be

 

 

 

 

left open.

 

 

 

 

 

123

AUI Receive

RECP

Diff. Input

AUI receive differential inputs.

124

 

RECN

 

 

 

 

 

 

 

2

AUI

TXP/nCOLL

Diff.

Internal ENDEC - (nXENDEC pin open). In

3

Transmit

TXN/nCRS

Output

this mode TXP and TXN are the AUI transmit

 

 

 

 

differential outputs. They must be externally

 

 

 

 

pulled up using 150 ohm resistors.

 

 

 

I

External ENDEC - (nXENDEC pin tied low).

 

 

 

 

In this mode the pins are inputs used for

 

 

 

 

collision and carrier sense functions.

 

 

 

 

 

 

 

 

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SMC Networks SMC91C95 manual Rxclk, Txd, Register, Aui