SN54BCT8245A, SN74BCT8245A

SCAN TEST DEVICES

WITH OCTAL BUS TRANSCEIVERS

SCBS043E – MAY 1990 – REVISED JULY 1996

2

POST OFFICE BOX 655303

description (continued)

Four dedicated test terminals 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 SN54BCT8245A is characterized for operation over the full military temperature range of –55

°C to 125°C.

The SN74BCT8245A is characterized for operation from 0

°C to 70°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

SCAN

’BCT8245A

TDI

14

TDI

TCK-IN

G3

24

TMS

12

TMS

13

TCK

3 EN1 [BA]

1

DIR

TCK-OUT

OE

Φ

2

3 EN2 [AB]

11

TDO

11

TDO

A1

23

A2

22

B1

2

B2

3

A3

21

B3

4

A4

20

B4

5

A5

19

B5

7

A6

17

B6

8

A7

16

B7

9

A8

15

B8

10

† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.

Pin numbers shown are for the DW, JT, and NT packages.