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2

Logic Symbols

IEEE/IEC

Data I/O Control Table

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

Functional Description

The LCX543 contains two sets of eight D-type latches, with

separate input and output controls for each set. For data

flow from A to B, for example, the A-to-B Enable (CEAB)

Table. With CEAB LOW, a LOW signal on the A-to-B Latch

Enable (LEAB) input makes the A-to-B latches transparent;

a subsequent LOW-to-HIGH transition of the LEAB signal

puts the A latches in the storage mode and their outputs no

longer change with the A inputs. With CEAB and OEAB

both LOW, the 3-STATE B output buffers are active and

reflect the data present at the output of the A latches. Con-

trol of data flow from B to A is similar, but using the CEBA,

LEBA and OEBA inputs.

Logic Diagram

Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.

Inputs

Latch Status

Output Buffers

CEAB LEAB OEAB

H

X

X

Latched

High Z

X

H

X

Latched

—

L

L

X

Transparent

—

XX

H

—

High Z

LX

L

—

Driving