Datasheet

SN54BCT8240A, SN74BCT8240A
SCAN TEST DEVICES
WITH OCTAL INVERTING BUFFERS
SCBS067E – FEBRUARY 1990 – REVISED DECEMBER 1996
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
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 SN54BCT8240A is characterized for operation over the full military temperature range of –55°C to 125°C.
The SN74BCT8240A is characterized for operation from 0°C to 70°C.
FUNCTION TABLE
(normal mode, each buffer)
INPUTS
OUTPUT
OE A
Y
H X Z
L LH
L H L
logic symbol
†
SCAN
’BCT8240A
23
1A1
1Y1
2
TDI
14
TDI
TCK-IN
EN1
1
22
1A2
1Y2
3
TMS
12
TMS
13
TCK
EN2
24
TCK-OUT
21
1A3 1Y3
4
20
1A4 1Y4
5
19
2A1 2Y1
7
17
2A2 2Y2
8
16
2A3 2Y3
9
15
2A4 2Y4
10
2OE
1OE
Φ
1
2
TDO
11
TDO
†
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.