www.fairchildsemi.com

2

Truth Tables

H

= HIGH Voltage Level

L

= LOW Voltage Level

X

= Immaterial

Z

= High Impedance

Note 1: Inactive-to-Active transition must occur to enable outputs upon power-up.

Functional Description

The SCAN182245A consists of two sets of nine non-invert-

ing bidirectional buffers with 3-STATE outputs and is

intended for bus-oriented applications. Direction pins (DIR1

and DIR2) LOW enables data from B Ports to A Ports,

when HIGH enables data from A Ports to B Ports. The Out-

put Enable pins (G1 and G2) when HIGH disables both A

and B Ports by placing them in a high impedance condition.

Block Diagrams

A1, B1, G1 and DIR1

Note: BSR stands for Boundary Scan Register.

A2, B2, G2 and DIR2

Note: BSR stands for Boundary Scan Register.

Tap Controller

Inputs

G1

(Note 1)

DIR1

LL

H

←

H

LL

L

←

L

LH

H

→

H

LH

L

→

L

HX

Z

Z

Inputs

G2

(Note 1)

DIR2

LL

H

←

H

LL

L

←

L

LH

H

→

H

LH

L

→

L

HX

Z

Z