SN54ABT8245, SN74ABT8245

SCAN TEST DEVICES

WITH OCTAL BUS TRANSCEIVERS

SCBS124D – AUGUST 1992 – REVISED DECEMBER 1996

2

POST OFFICE BOX 655303

description (continued)

In the test mode, the normal operation of the SCOPE

™ bus transceivers is inhibited and the test circuitry is

enabled to observe and control the I/O boundary of the device. When enabled, the test circuitry can perform

boundary-scan test operations as described in IEEE Standard 1149.1-1990.

Four dedicated test pins control the operation of the test circuitry: test data input (TDI), test data output (TDO),

test mode select (TMS), and test clock (TCK). Additionally, the test circuitry performs other testing functions

such as parallel-signature analysis (PSA) on data inputs and pseudo-random pattern generation (PRPG) from

data outputs. All testing and scan operations are synchronized to the TAP interface.

The SN54ABT8245 is characterized for operation over the full military temperature range of – 55

°C to 125°C.

The SN74ABT8245 is characterized for operation from – 40

°C to 85°C.

FUNCTION TABLE

(normal mode)

INPUTS

OPERATION

OE

DIR

OPERATION

L

L

B data to A bus

L

H

A data to B bus

H

X

Isolation