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Functional Description

In the transceiver mode, data present at the HIGH impedance port may be stored in either the A or B register or both. The

select (SAB, SBA) controls can multiplex stored and real-time. The examples below demonstrate the four fundamental bus-

management functions that can be performed.

The direction control (DIR) determines which bus will receive data when OE is LOW. In the isolation mode (OE HIGH), A

data may be stored in one register and/or B data may be stored in the other register. When an output function is disabled,

the input function is still enabled and may be used to store and transmit data. Only one of the two busses, A or B, may be

driven at a time.

Real-Time Transfer

Bus B to Bus A

Transfer Storage

Data to A or B

Real-Time Transfer

Bus B to Bus A

Storage

OE

DIR

CPAB CPBA SAB SBA

LL

X

X

X

L

OE

DIR

CPAB CPBA SAB SBA

LL

X

H or L

X

H

LH

H or L

X

H

X

OE

DIR

CPAB CPBA SAB SBA

LH

X

X

L

X

OE

DIR

CPAB CPBA SAB SBA

LH



XL

X

LL

X



XL

HX



XX

X

HX

X



XX