SIGNAL

FUNCTION

DESCRIPTION

VALID WORD

OUTPUT

A high output signals the receipt ofa valid word

ENCODER SHIFT CLOCK

OUTPUT

Shifts data into the encoder ona low to high transition

TAKE DATA

OUTPUT

Output is high during receipt of data after identification ofa Sync

Pulse and two valid Manchester data bits.

SERIAL DATA OUT

OUTPUT

Received Data output in NRZ format

DECODER CLOCK

INPUT

12x the data rate. Clock for the transition finder and synchronizer,

which generates the internal clock for the remainder of the decoder

BIPOLAR ZERO IN

INPUT

A high input indicates the 1553 bus is in its negative state.

This pin must be held high when the Unipolar input is used

BIPOLAR ONE IN

INPUT

A high input indicates the 1553 bus is in the positive state.

This pin must be held low when the Unipolar input is used

UNIPOLAR DATA IN

INPUT

Input for unipolar data to the transition finder. Must be held low when

not in use

DECODER SHIFT CLOCK

OUTPUT

Provides the DECODER CLOCK divided by 12, synchronized by the

recovered serial data

COMMAND /

SYNC

OUTPUT

A high on this pin occurs during the output of decoded data which

was preceded bya Command (or Status) synchronizing character.A

low output indicatesa Data synchronizing character

DECODER RESET

INPUT

A high applied to this pin duringa DECODER SHIFT CLOCK rising

edge resets the bit counter

GND

POWER

0V supply

MASTER RESET

INPUT

A high on this pin clears 2:1 counters in both Encoder and Decoder,

and resets the divide-by-6 circuit

6 OUT

OUTPUT

Provides ENCODER CLOCK divided by6

OUTPUT

An active low output intended to drive the zero or negative sense ofa

MIL-STD-1553 Line Driver

INPUT

A low inhibits the

and

by

forcing them to inactive high states

OUTPUT

An active low output intended to drive the one or positive sense ona

MIL-STD-1553 Line Driver

SERIAL DATA IN

INPUT

Receiver serial data at the rate of the ENCODER SHIFT CLOCK

ENCODER ENABLE

INPUT

A high on this pin initiates the encode cycle. (Subject to the

preceeding cycle being complete)

SYNC SELECT

INPUT

Actuatesa Command Sync for an input high anda Data Sync fora

low

SEND DATA

OUTPUT

An active high output which enables the external source of serial

Data

SEND CLOCK IN

INPUT

Clock input at2 times the Data rate, usualy driven by 6 OUT

ENCODER CLOCK

INPUT

Input to the divide by6 circuit. Normal frequency is Data rate x12

VDD

POWER

5V +/- 10%

DATA

BIPOLAR ZERO OUT

OUTPUT INHIBIT

BIPOLAR ZERO OUT

BIPOLAR ONE OUT

BIPOLAR ONE OUT

÷

÷

PIN DESCRIPTIONS

HOLT INTEGRATED CIRCUITS

2

HI-15530