DESCRIPTION OF PIN FUNCTIONS

PIN NO.

NAME

SYMBOL

TYPE

DESCRIPTION

 

 

 

 

 

113

 

nROM/

I/O4 with

This pin is sampled at the end of RESET.

 

 

nPCMCIA

pullup

When this pin is sampled low the SMC91C95

 

 

 

 

is configured for PCMCIA operation and all

 

 

 

 

pin definitions correspond to the PCMCIA

 

 

 

 

mode. For ISA operation this pin is left open

 

 

 

 

and is used as a ROM chip select output that

 

 

 

 

goes active when nMEMR is low and the

 

 

 

 

address bus contains a valid ROM address.

 

 

 

 

 

35, 36,

Address 0-

A0-A15

I

Input address lines 0 through 15.

38-43,

15

 

 

 

45-50,

 

 

 

 

52, 53

 

 

 

 

 

 

 

 

 

54

Address 16

A16

I

ISA - Input address line 16.

 

nFlash

nFWE

O4

PCMCIA - Output. Flash Memory Write

 

Memory

 

 

Enable used for programming the attribute

 

Write

 

 

memory. Goes active (low) when nWE=0 and

 

 

 

 

WRATTRIB=1 (in ECOR bit 3).

 

 

 

 

 

55

Address 17

A17

I

ISA - Input address line 17.

 

nFlash

nFCS

O4

PCMCIA - Output. Flash Memory Chip Select

 

Memory

 

 

used to access attribute memory. Goes active

 

Chip Select

 

 

(low) when nREG=0, nCE1=0 and A15=0.

 

 

 

 

 

56

Address 18

A18

I

Input address line 18.

 

 

 

 

 

57

Address 19

A19

I with pullup

ISA - Input address line 19.

 

Card Enable

nCE1

 

PCMCIA - Card Enable 1 input. Used to

 

1

 

 

select card on even byte accesses.

 

 

 

 

 

34

Address

AEN

I with pullup

ISA - Address enable input. Used as an

 

Enable

 

 

address qualifier. Address decoding is only

 

 

 

 

enabled when AEN is low.

 

 

nREG

 

PCMCIA - Attribute memory and IO select

 

 

 

 

input. Asserted when the card attribute space

 

 

 

 

or IO space is being accessed.

 

 

 

 

 

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SMC Networks SMC91C95 manual Description of PIN Functions, PIN no Name Symbol Type Description