Datasheet

SN74ABT18502
SCAN TEST DEVICE
WITH 18-BIT REGISTERED BUS TRANSCEIVER
SCBS753 – FEBRUARY 2002
11
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Table 3. Device IDR Configuration
IDR BIT
NUMBER
IDENTIFICATION
SIGNIFICANCE
IDR BIT
NUMBER
IDENTIFICATION
SIGNIFICANCE
IDR BIT
NUMBER
IDENTIFICATION
SIGNIFICANCE
31 VERSION3 27 PARTNUMBER15 11 MANUFACTURER10
†
30 VERSION2 26 PARTNUMBER14 10 MANUFACTURER09
†
29 VERSION1 25 PARTNUMBER13 9 MANUFACTURER08
†
28 VERSION0 24 PARTNUMBER12 8 MANUFACTURER07
†
–– –– 23 PARTNUMBER11 7 MANUFACTURER06
†
–– –– 22 PARTNUMBER10 6 MANUFACTURER05
†
–– –– 21 PARTNUMBER09 5 MANUFACTURER04
†
–– –– 20 PARTNUMBER08 4 MANUFACTURER03
†
–– –– 19 PARTNUMBER07 3 MANUFACTURER02
†
–– –– 18 PARTNUMBER06 2 MANUFACTURER01
†
–– –– 17 PARTNUMBER05 1 MANUFACTURER00
†
–– –– 16 PARTNUMBER04 0 LOGIC1
†
–– –– 15 PARTNUMBER03 –– ––
–– –– 14 PARTNUMBER02 –– ––
–– –– 13 PARTNUMBER01 –– ––
–– –– 12 PARTNUMBER00 –– ––
†
Note that for TI products, bits 11–0 of the device IDR always contains the binary value 000000101111 (02F, hex).
instruction-register (IR) opcode
The IR opcodes are shown in Table 4. The following descriptions detail the operation of each instruction.
Table 4. IR Opcodes
BINARY CODE
‡
BIT 7 → BIT 0
MSB → LSB
SCOPE OPCODE DESCRIPTION SELECTED DR MODE
00000000 EXTEST Boundary scan Boundary scan Test
10000001 IDCODE Identification read Device identification Normal
10000010 SAMPLE/PRELOAD Sample boundary Boundary scan Normal
00000011 INTEST Boundary scan Boundary scan Test
10000100 BYPASS
§
Bypass scan Bypass Normal
00000101 BYPASS
§
Bypass scan Bypass Normal
00000110 HIGHZ Control boundary to high impedance Bypass Modified test
10000111 CLAMP Control boundary to 1/0 Bypass Test
10001000 BYPASS
§
Bypass scan Bypass Normal
00001001 RUNT Boundary run test Bypass Test
00001010 READBN Boundary read Boundary scan Normal
10001011 READBT Boundary read Boundary scan Test
00001100 CELLTST Boundary self test Boundary scan Normal
10001101 TOPHIP Boundary toggle outputs Bypass Test
10001110 SCANCN BCR scan Boundary control Normal
00001111 SCANCT BCR scan Boundary control Test
All others BYPASS Bypass scan Bypass Normal
‡
Bit 7 is used to maintain even parity in the 8-bit instruction.
§
The BYPASS instruction is executed in lieu of a SCOPE instruction that is not supported in the SN74ABT18502.