TC74VCXR162646FT

2007-10-19

3

Truth Table

Control Inputs

Bus

OE

DIR

CAB

CBA

SAB

SBA

A

B

Function

Input

Input

X

X

Z

Z

The output functions of A and B Busses are

disabled.

H

X

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

L

X

H

H

The data on the A bus are displayed on the

B bus.

L

L

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.

H

X

X

Qn

The data in the A storage flop-flops are

displayed on the B Bus.

L

L

L

H

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

L

H

H

The data on the B Bus are displayed on the

A bus.

L

L

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

H

Qn

X

The data in the B storage flip-flops are

displayed on the A Bus.

L

L

L

L

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.

X: Don’t care

Z: High impedance

*: The clocks are not internally with either OE or DIR.

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