xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 339

• Manufacturer Part Number: xrt94l33
• Description: Multi-channel, Multi-function Device Aggregates 3 Ds3/e3/sts-1 Into Oc3/stm-1
• Manufacturer: Exar Corporation

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3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Figure 81 Illustration of the “Receive STS-3 TOH Processor” Block Framing Alignment State-Machine
2.3.1.3.1
When the XRT94L33 first powers up, the Receive STS-3 TOH Processor block will be operating in this state.
In this case, both the LOF (Loss of Frame) and the SEF (Severely Erred Frame) defect conditions are
declared. The Receive STS-3 TOH Processor block will indicate this fact by setting both Bits 2 (LOF Defect
Declared) and 1 (SEF Defect Declared), within the “Receive STS-3 Transport Status Register – Byte 0” as
depicted below.
Receive STS-3 Transport Status Register – Byte 0 (Address = 0x1107)
The Receive STS-3 TOH Processor block will remain in this condition until it receives two consecutive STS-3
frames that contain no framing byte errors. At this point the Receive STS-3 TOH Processor block will clear
the SEF defect and will transition into the “SEF = 0, LOF = 1” State.
As the Receive STS-3 TOH Processor block transitions from the “SEF = 1, LOF = 1” state to the “SEF = 0,
LOF = 1” state, it will do all of the following.
Declared
Defect
RDI-L
B
R/O
IT
0
7
The “SEF = 1, LOF = 1” State
SEF Defect persists
For 3ms.
Unstable
Declared
S1 Byte
Defect
B
R/O
IT
0
6
K1, K2 Byte
Declared
Unstable
Defect
B
R/O
LOF = 1
SEF = 1
IT
0
LOF = 1
SEF = 1
5
LOF = 0
SEF = 1
LOF = 0
SEF = 1
SF Defect
Declared
Framing Byte Errors
Detected in 4 Consecutive
SONET Frames
B
R/O
IT
0
Un-erred Framing Bytes are
Detected in 2 consecutive SONET
Frames
4
339
Un-erred Framing Bytes are
Detected in 2 consecutive SONET
Frames
SD Defect
Declared
B
LOF = 1
R/O
SEF = 0
LOF = 1
SEF = 0
IT
0
3
In Frame
In Frame
State
State
Declared
Defect
B
LOF
R/O
Un-erred Framing Bytes are
Detected in a “User-Selectable”
Number of consecutive SONET
Frames
IT
1
2
Framing Byte Errors
Detected in 3 (or less)
Consecutive SONET
Frames
Declared
Defect
B
SEF
R/O
IT
1
1
XRT94L33
Declared
Defect
Rev.1.2.0.
B
LOS
R/O
IT
0
0