TC74LCX652FS

2002-01-11

3

Truth Table

Control Inputs

Bus

OEAB

OEBA

CAB

CBA

SAB

SBA

A

B

Function

Input

Input

X*

X*

X

X

Z

Z

The output functions of A and B busses are

disabled.

L

H

X

X

X

X

Both A and B busses are used as inputs to

the internal flip-flops. Data on the bus will be

stored on the rising edge of the Clock.

Input

Output

L

L

X*

X*

L

X

H

H

The data on the A bus are displayed on the

B bus.

L

L

X*

L

X

H

H

The data on the A bus are displayed on the

B bus, and are stored into the A storage

flip-flops on the rising edge of CAB.

X*

X*

H

X

X

Qn

The data in the A storage flop-flops are

displayed on the B bus.

L

L

H

H

X*

H

X

H

H

The data on the A bus are stored into the A

storage flip-flops on the rising edge of CAB,

and the stored data propagate directly onto

the B bus.

Output

Input

L

L

X*

X*

X

L

H

H

The data on the B bus are displayed on the

A bus.

L

L

X*

X

L

H

H

The data on the B bus are displayed on the

A bus, and are stored into the B storage

flip-flops on the rising edge of CBA.

X*

X*

X

H

Qn

X

The data in the B storage flip-flops are

displayed on the A bus.

L

L

L

L

X*

X

H

H

H

The data on the B bus are stored into the B

storage flip-flops on the rising edge of CBA,

and the stored data propagate directly onto

the A bus.

Output

Output

H

L

X*

X*

H

H

Qn

Qn

The data in the A storage flop-flops are

displayed on the B bus, and the data in the B

storage flop-flops are displayed on the A.

X: Don’t care

Z: High impedance

*: The clocks are not internally gated with either OEAB or OEBA .

Therefore, data on the A and/or B busses may be clocked into the storage flip-flops at any time.