3

FN6202.1

December 20, 2005

TABLE 2. ISL81334 FUNCTION TABLE

INPUTS

RECEIVER OUTPUTS

DRIVER OUTPUTS

CHARGE PUMPS

(NOTE 1)

MODE

SEL1 or 2

ON/OFF

DE 1 or 2

YZ

0

1

N.A.

ON

ON

ON

ON

ON

RS-232

X

0

X

High-Z

High-Z

High-Z

High-Z

OFF

Shutdown

1

1

0

ON

High-Z *

High-Z

High-Z

OFF

RS-485

1

1

1

ON

High-Z *

ON

ON

OFF

RS-485

NOTE:

1. Charge pumps are off iff SEL1 = SEL2 = 1, or if ON/OFF = 0. If ON = 1, and either port is programmed for RS-232 mode, then the charge

pumps are on.

RS-232 TRANSMITTING MODE

INPUTS

OUTPUTS

SEL1 or 2 ON/OFF

YZ

0

10011

0

10110

0

11001

0

11100

0

0

X

X

High-Z

High-Z

RS-232 RECEIVING MODE

INPUTS

OUTPUT

SEL1 or 2 ON/OFF

AB

0

10011

0

10110

0

11001

0

11100

0

1

Open

Open

1

1

0

0

X

X

High-Z

High-Z

RS-485 TRANSMITTING MODE

INPUTS

OUTPUTS

SEL1 or 2 ON/OFF DE1 or 2

YZ

1

11010

1

11101

1

1

0

X

High-Z

High-Z

1

0

X

X

High-Z

High-Z

RS-485 RECEIVING MODE

INPUTS

OUTPUT

SEL1 or 2 ON/OFF

B-A

11

≥ -40mV

1

High-Z

11

≤ -200mV

0

High-Z

1

1

Open or Shorted together

1

High-Z

1

0

X

High-Z

High-Z

* Internally pulled high through a 40k

Ω resistor.

ISL81334, ISL41334