8-2

Functional Diagram

IEC Logic Symbol

TRUTH TABLE For A to B (Symmetric with B to A)

INPUTS

LATCH STATUS

OUTPUT BUFFERS

CEAB

LEAB

OEAB

A TO B

B0 THRU B7

H

X

X

Storing

High Z

XH

−

Storing

-

X

-

H

-

High Z

L

L

L

Transparent

Current A Inputs

L

H

L

Storing

Previous A Inputs (Note 1)

NOTE:

1. Before LEAB LOW to HIGH Transition

H = HIGH Voltage Level

L = LOW Voltage Level

X = Immaterial

A to B data flow shown; B to A flow control is the same, except using CEBA, LEBA, and OEBA.

D

LE

Q

DETAIL A

DETAIL A x 7

Q

D

LE

B0

B1

B7

OEAB

CEAB

LEAB

A0

A1

A7

OEBA

CEBA

LEBA

CD74FCT543

22

21

20

19

18

17

16

EN1

15

EN2

3

4

5

6

7

8

9

10

≥1

≥1

11

14

13

23

1

2

12

CD74FCT543