3

PS2022A 03/11/96

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PI74FCT646/648/651/652T

(25

Ω

Ω

Ω

Ω

Ω Series) P174FCT2646T/2652T

OCTAL REGISTERED TRANSCEIVERS

REAL-TIME TRANSFER

BUS B TO A

646/648/

DIR

G

CPAB CPBA

SAB

SBA

2646

L

L

XXX

L

651/652/

GAB GBA CPAB CPBA

SAB

SBA

2652

L

L

XXX

L

REAL-TIME TRANSFER

BUS A TO B

646/648/

DIR

G

CPAB CPBA

SAB

SBA

2646

HL

X

X

L

X

651/652/

GAB GBA CPAB CPBA

SAB

SBA

2652

HH

X

X

L

X

STORAGE FROM

A AND/OR B

TRANSFER STORES

DATA TO A AND/OR B

646/648/

DIR

G

CPAB CPBA

SAB

SBA

2646

HL

↑

XX

X

LL

X

↑

XX

XH

↑↑

XX

651/652/

GAB GBA CPAB CPBA

SAB

SBA

2652

XH

↑

XX

X

LX

X

↑

XX

LH

↑↑

XX

646/648

G

CPAB CPBA

SAB

SBA

2646

L

L

X

H or L

X

H

H

L

H or L

X

H

X

651/652/

GAB GBA CPAB CPBA

SAB

SBA

2652

H

L

H or L

H or L

H

H

1. Note: The FCT646/2646 cannot transfer data to

A bus and B bus simultaneously.

BUS

A

BUS

B

BUS

A

BUS

B

BUS

A

BUS

B

BUS

A

BUS

B