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2

Logic Symbols

IEEE/IEC

Truth Table

(Note 2)

H

= HIGH Voltage Level

L

= LOW Voltage Level

X

= Immaterial

 = LOW-to-HIGH Transition

Note 2: The data output functions may be enabled or disabled by various signals at the OE and DIR inputs. Data input functions are always enabled;

i.e., data at the bus pins will be stored on every LOW-to-HIGH transition of the appropriate clock inputs.

Inputs

Data I/O

Function

OE

DIR

CPAB CPBA

SAB

SBA

H

X

H or L H or L

X

X

Isolation

HX



X

X

X

Input

Input

HX

X



X

X

LH

X

X

L

X

LH



X

L

X

Input

Output

L

H

H or L

X

H

X

LH



X

H

X

L

L

XXX

L

LL

X



X

L

Output

Input

L

L

X

H or L

X

H

LL

X



X

H