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IDT EJTAG System
EJTAG Test Access Port
79RC32438 User Reference Manual
20 - 62
November 4, 2002
Notes
Implementation Register (TAP Instruction IMPCODE)
Compliance Level
: Required with EJTAG TAP feature.
The Implementation register is a 32-bit read-only register that identifies features implemented in this
EJTAG compliant processor, mainly those accessible from the TAP.
Figure 20.29 shows the format of the Implementation register and Table 20.44 describes the Implemen-
tation register fields.
ManufID
11:1
Identifies the manufacturer identity code of
a specific device, which identifies the
design house implementing the processor.
According to IEEE 1149.1-1990 section
11.2, the manufacturer identity code is a
compressed form of a JEDEC standard
manufacturer’s identification code in the
JEDEC Publications 106, which can be
found at:
http://www.jedec.org/
ManufID[6:0] are derived from the last byte
of the JEDEC code with the parity bit dis-
carded. ManufID[10:7] provide a binary
count of the number of bytes in the JEDEC
code that contain the continuation charac-
ter (0x7F). When the number of continua-
tions characters exceeds 15, these four
bits contain the modulo-16 count of the
number of continuation characters.
If the design house does not have a
JEDEC Standard Manufacturer's Identifi-
cation Code, which is encoded for use in
this field, the design house can request
use of the MIPS Technologies, Inc.
assigned number, or use the number
assigned to the core provider. Use of the
MIPS Technologies, Inc. number requires
prior approval of the Director, MIPS Archi-
tecture.
The MIPS Technologies, Inc. Standard
Manufacturer's Identification Code is
0x127.
R
Preset
Required
1
0
Ignored on write; returns one on read.
R
Preset
Required
31
EJTAGver R4k/
29 28 27
25 24 23 22 21 20
DI
NT
sup
17 16 15 14 13
MI
PS
16
1
0
R3k
0
0
1
1.
Select either 000 or 010.
ASID
size
0
0
No
DM
A
0
MIPS
32
010
0000
Figure 20.29 Implementation Register Format
Fields
Description
Read/
Write
Power-up
State
Compli-
ance
Name
Bits
Table 20.43 Device ID Register Field Description (Part 2 of 2)