Philips Semiconductors

Product specification

74ALS651/74ALS651-1

74ALS652/74ALS652-1

Transceiver/register

1991 Feb 08

4

BUS MANAGEMENT FUNCTIONS

The following examples demonstrate the four fundamental

bus-management functions that can be performed with the

74ALS651/74ALS651-1 and 74ALS652/74ALS652-1. The select

pins determine whether data is stored or transferred through the

device in real time. The output enable pins determine the direction of

the data flow.

REAL TIME BUS TRANSFER

BUS B TO BUS A

REAL TIME BUS TRANSFER

BUS A TO BUS B

STORAGE FROM

A, B, OR A AND B

TRANSFER STORED DATA

TO A AND/OR B

BUS A

BUS A

BUS A

BUS A

BUS B

BUS B

BUS B

BUS B

OEAB OEBA CPAB CPBA SAB SBA

LL

X

X

X

L

OEAB OEBA CPAB CPBA SAB SBA

HH

X

X

L

X

OEAB OEBA CPAB CPBA SAB SBA

XX

↑

XX

X

LX

X

↑

XX

LX

↑↑

XX

OEAB OEBA CPAB CPBA SAB SBA

H

L

H or L H or L

H

H

SC00133