AD15–AD12

AD11–AD8

IDEQ

EQ 0

X

NE 0

EQ ID3–ID0

NE ID3–ID0

X

L

H

H

SN74BCT2420

NuBus

™ ADDRESS/DATA TRANSCEIVERS AND REGISTERS

SDIS007A – D3159, NOVEMBER 1988 – REVISED JANUARY 1989

POST OFFICE BOX 655303

2

Function Tables

INPUTS

OUTPUTS

A15–A0

D15–D0

ALE

DLE

A/D

ADEN

AD15–AD0

H

X

L

X

L

L

L

L

XLX

L

L

H

X

XH

X

L

L

QO

X

HX

L

H

L

L

X

LX

L

H

L

H

X

XX

H

H

L

QO

X

X

X

X

X

H

Z

INPUTS

OUTPUTS

AD15–AD0

ACLK, DCLK

AEN, DEN

A15–A0, D15–DO

H

↑

L

L

L

↑

LH

X

LL

QO

X

X

H

L

AD15–AD12

ID3–ID0

SSEQ

EQ ID3–ID0

NE 0

L

NE ID3–ID0

XH

X

EQ 0

H

NOTE: Symbol ‘QO’ denotes previous logic state preserved. Symbol ‘Z’ denotes high-impedance state.