SN54ABT853, SN74ABT853

8-BIT TO 9-BIT PARITY BUS TRANSCEIVERS

SCBS198F – FEBRUARY 1991 – REVISED OCTOBER 1997

2

POST OFFICE BOX 655303

description (continued)

The SN54ABT853 is characterized for operation over the full military temperature range of –55

°C to 125°C. The

SN74ABT853 is characterized for operation from –40

°C to 85°C.

FUNCTION TABLE

INPUTS

OUTPUTS AND I/Os

OEB

OEA

CLR

LE

Ai

Σ OF H

Bi†

Σ OF H

A

B

PARITY

ERR‡

FUNCTION

L

H

X

X

Odd

NA

NA

A

L

NA

A data to B bus and

L

H

X

X

Even

NA

NA

A

H

NA

generate parity

H

L

X

L

NA

Odd

B

NA

NA

H

B data to A bus and

H

L

X

L

NA

Even

B

NA

NA

L

check parity

H

L

H

H

NA

X

X

NA

NA

NC

Store error flag

X

X

L

H

X

X

X

NA

NA

H

Clear error flag register

H

H

X

NC

§

H

H

LH

X

X

Z

Z

Z

H

Isolation§

H

H

X

L

L Odd

X

Z

Z

Z

H

(parity check)

X

L

H Even

L

L

L

X

X

Odd

NA

NA

A

H

NA

A data to B bus and

L

L

X

X

Even

NA

NA

A

L

NA

generate inverted parity

NA = not applicable, NC = no change, X = don’t care

† Summation of high-level inputs includes PARITY along with Bi inputs.

‡ Output states shown assume ERR was previously high.

§ In this mode, ERR (when clocked) shows inverted parity of the A bus.

ERR

CLR

OEA

OEB

CLR

11

1

2

A1

3

A2

4

A3

5

A4

10

PARITY

15

PARITY

B5

19

B6

18

B7

17

B8

16

8

OEA

1

OEB

14

6

A5

7

A6

8

A7

8

9

A8

B1

23

1

B2

22

B3

21

B4

20

ERR

Φ

A Bus

B Bus

LE

LE

13

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

Pin numbers shown are for the DB, DW, JT, NT, PW, and W packages.