Aeroflex Circuit Technology

SCD15530 REV B 7/28/99 Plainview NY (516) 694-6700

3

Pin Designations

Pin

Input

Output

Enc

Dec

Function

Comment

1





Valid word

A 'high' signals the receipt of a valid word

2





Encoder Shift Clock

Shifts data into the encoder on a 'low' to 'high'

transition

3





Take Data

'high' during data reception after the sync pulse is

identified

4





Serial Data Out

NRZ output of received data

5





Decoder clock

Clock for the transition finder and synchronizer which

generates the clock for the rest of the decoder

6





Bipolar Zero In

Should be 'high' when the bus is in a negative state.

Must be tied 'high' when the unipolar input is used

7





Bipolar One In

Should be 'high' when the bus is in a positive state.

Must be tied 'low' when the unipolar input is used

8





Unipolar Data In

Input for unipolar data to the transition finder. Must be

tied 'low' when not used

9





Decoder Shift Clock

Provides the DECODER CLOCK divided by 12,

synchronized by the recovered serial data

10





Command/Data Sync

This output indicates the type of synchronizing

character received as follows: If a data synchronizing

character was received, this pin is low while the data

is decoded. If a command synchronizing character

was received, this pin is high during data decoding

11





Decoder Reset

A 'high' during a DECODER SHIFT CLOCK rising

edge resets the bit counter

12

–

–





Ground

13







Master Reset

A 'high" clears the counters in both sections

14





Provides the ENCODER CLOCK divided by 6

15





Bipolar Zero Out

Provides an active 'low' output to the zero or negative

sense of a bipolar line driver

16





Output Inhibit

A 'low' inhibits the BIPOLAR ZERO OUT and

BIPOLAR ONE OUT by forcing them to inactive, 'high',

states

17





Bipolar One Out

Provides an active 'low' output to the one or positive

sense of a bipolar line driver

18





Serial Data In

Receives serial data at the rate of the ENCODER

SHIFT CLOCK

19





Encoder Enable

A 'high' starts the encode cycle provided that the

previous cycle is complete

20





Sync Select

A 'high' selects the command sync and a 'low' selects

the data sync

21





Send Data

Provides an active 'high' to enable the external serial

data source

22





Send Clock In

Clock input at 2 times the data rate

23





Encoder Clock

Input to the divide by 6 circuit

24

–

–





Positive Supply

Figure 4: Pin Designations (24-Pin Dip/FlatPack)