
PRELIMINARY
XRT86SH221
286
REV. P1.0.5
SDH-TO-PDH FRAMER/MAPPER WITH INTEGRATED 21-CHANNEL E1 SH LIU
BIT [7:6] - Received TC Enable[1:0]:
These two READ/WRITE bit-fields are used to enable the Tandem Connection feature in the VT DeMapper. The VT
Path Trace Message Length [1:0] on Bit-1 and Bit-0 must be set to the value "0x01" or "0x00" depending on the expected
16 bytes or 1 byte message length.
The relationship between the contents of these bit-fields and the corresponding Receive Tandem Connection
Messaging Type is presented below.
BIT 5 - Reserved:
BIT 4 - Received 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.
b.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
T
ABLE
257: C
HANNEL
C
ONTROL
- VT-D
E
-M
APPER
P
ATH
T
RACE
B
UFFER
C
ONTROL
R
EGISTER
(VTDPTBCR =
0
X
ND71)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Receive TC Enable [1:0]
Reserved
Receive VT
Path Trace
Message
Buffer Select
VT Path
Trace Mes-
sage 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
R
ECEIVE
TC E
NABLE
[1:0]
R
ECEIVE
T
ANDEM
C
ONNECTION
O
PERATION
00
Tandem Connection feature is disabled.
01
Tandem Connection Enabled for 16-Byte Messaging Operation. The N2
Byte Messaging memory buffer segment is shared with the J2 64-Byte
memory buffer. 16-Bytes message length must be selected using the
appropriate values written on VT Path Trace Message Length[1:0] Bit-1
and Bit-0.
10
Reserved.
11
Tandem Connection Enabled for 1-Byte Messaging Operation. 1-Byte
message length must be selected using the appropriate values written on
VT Path Trace Message Length[1:0] Bit-1 and Bit-0.