
PRELIMINARY
XRT86SH328
321
REV. P1.0.6
28-CHANNEL DS1/E1 FRAMER/LIU WITH DS3 MUX & VT-MAPPER - SONET APPLICATIONS
Bit 7 - 6 - Reserved
For Normal Operation, please set these two bit-fields to "0".
Bit 5 - Unused
Bit 4 - Receive VT Path Trace Message Buffer Select:
This READ/WRITE bit-field permits a user to specify which of the following "Receive VT Path Trace Message"
buffer segments that the Microprocessor will read out whenever it reads out the contents of the Receive Path
Trace Message buffer.
a.
The "Actual" Receive VT Path Trace Message Buffer. The "Actual" Receive VT Path Trace Message Buffer
contains the contents of the most recently received (and accepted) VT Path Trace Messages via the incoming
VT-data-stream.
The "Expected" Receive VT Path Trace Message Buffer. The "Expected" Receive Path Trace Message
Buffer contains the contents of the "VT Path Trace Message" that the user "expects" to receive. The contents
of this particular buffer are usually specified by the user.
`
0 - Configures the chip to return the contents of the "Actual" Receive VT Path Trace Message" Buffer, whenever the
user executes a READ to the "Receive VT Path Trace Message" Buffer.
`
1 - Configures the chip to return the contents of the "Expected" Receive VT Path Trace Message" Buffer, whenever
the user executes a READ to the "Receive VT Path Trace Message" Buffer.
Bit 3 - Receive VT Path Trace Message Accept Threshold
This READ/WRITE bit-field permits a user to select the number of consecutive times that the "VT-De-Mapper" block
must receive a given "VT Path Trace Message" before it is "validated" and loaded into the "Actual" Receive VT Path
Trace Message Buffer, as described below.
`
0 - Configures the VT-De-Mapper block to "validate" the incoming VT Path Trace Message after it has received it the
third time in succession.
`
1 - Configures the VT-De-Mapper block to "validate" the incoming VT Path Trace Message after it has received it the
fifth time in succession.
Bit 2 - Receive VT Path Trace Message Type
b.
This READ/WRITE bit-field permits the user to specify how the "VT-De-Mapper" block will locate the boundary
of the incoming VT Path Trace Message (within the incoming VT-data-stream) as depicted below.
`
0 - Configures the VT-De-Mapper block to expect the "VT Path Trace Message" boundary to be denoted by a "Line
Feed" character.
`
1 - Configures the VT-De-Mapper block to except the "VT Path Trace Message" boundary to be denoted by the
presence of a "1" in the "MSB" (Most Significant bit) of the first byte (within the incoming VT Path Trace Message). In
this case, all of the remaining bytes (within the incoming VT Path Trace Message) will each have a "0" within their MSBs.
Bits 1 - 0 - VT Path Trace Message Length[1:0]:
These READ/WRITE bit-fields permit the user to specify the length of the "Receive VT Path Trace Message that the
"VT-De-Mapper" block will accept and load into the "Actual" Receive VT Path Trace Message Buffer. The relationship
between the contents of these bit-fields and the corresponding "Receive VT Path Trace Message" Length is presented
T
ABLE
458: C
HANNEL
C
ONTROL
- VT-D
E
-M
APPER
B
LOCK
- E
GRESS
D
IRECTION
- VT-P
ATH
T
RACE
B
UFFER
C
ONTROL
R
EGISTER
(A
DDRESS
= 0
X
ND71,
WHERE
N
RANGES
IN
VALUE
FROM
0
X
01
TO
0
X
1C)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Reserved
Unused
Receive VT
Path Trace
Message
Buffer Select
VT Path
Trace
Message
Accept
Threshold
VT Path
Trace
Message
Type
VT Path Trace Message
Length[1:0]
R/W
R/W
RUR
RUR
RUR
R/O
R/O
R/O
0
0
0
0
0
0
0
0