MC74AC652, MC74ACT652

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3

FUNCTION TABLE

Inputs

Data I/O*

Operation or Function

GAB

GBA

CAB

CBA

SAB

SBA

L

H

H or L

H or L

X

X

Input

Input

Isolation

L

H

⇑

⇑

X

X

Store A and B Data

X

H

⇑

H or L

X

X

Input

Unspecified* Store A, Hold B

H

H

⇑

⇑

X**

X

Input

Output

Store A in Both Registers

L

X

H or L

⇑

X

X

Unspecified*

Input

Hold A, Store B

L

L

⇑

⇑

X

X**

Output

Input

Store B in Both Registers

L

L

X

X

X

L

Output

Input

Real-Time B Data to A Bus

L

L

X

H or L

X

H

Stored B Data to A Bus

H

H

X

X

L

X

Input

Output

Real-Time A Data to B Bus

H

H

H or L

X

H

X

Stored A Data to B Bus

H

L

H or L

H or L

H

H

Output

Output

Stored A Data to B Bus and

Stored B Data to A Bus

*The data output functions may be enabled or disabled by various signals at the GBA and GAB 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.

**Select control = L: clocks can occur simultaneously.

H = HIGH Voltage Level; L = LOW Voltage Level; X = Immaterial;

⇑ = LOW-to-HIGH Transition