SN74BCT657

OCTAL TRANSCEIVER WITH PARITY GENERATOR/CHECKER

AND 3STATE OUTPUTS

SCBS079B − NOVEMBER 1991 − REVISED APRIL 1994

2−2

POST OFFICE BOX 655303

POST OFFICE BOX 1443

FUNCTION TABLE

NUMBER OF A OR B

INPUTS

INPUT/OUTPUT

OUTPUTS

NUMBER OF A OR B

INPUTS THAT ARE HIGH

OE

T/R

ODD/EVEN

INPUT/OUTPUT

PARITY

ERR

OUTPUT MODE

L

H

H

H

Z

Transmit

L

HL

L

Z

Transmit

0, 2, 4, 6, 8

L

LH

H

H

Receive

0, 2, 4, 6, 8

L

LH

L

L

Receive

L

LL

H

L

Receive

L

LL

L

H

Receive

L

H

H

L

Z

Transmit

L

HL

H

Z

Transmit

1, 3, 5, 7

L

LH

H

L

Receive

1, 3, 5, 7

L

LH

L

H

Receive

L

LL

H

H

Receive

L

LL

L

L

Receive

Don’t care

H

X

X

Z

Z

Z

B2

22

B3

21

B4

20

B5

17

B6

16

B1

23

OE

T/R

3 EN1/3G5 [REC]

1

A2

3

A3

4

A4

5

A5

6

A6

8

A7

9

A8

10

B7

15

B8

14

ODD/EVEN

3 EN2 [XMIT]

1

2

2 k

5

4, 2

4, 1

ERR

Z11

1

G3

24

N4

11

11

A1

2

12

13

14

15

16

17

18

PARITY

13

12

† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.