![](http://datasheet.mmic.net.cn/Exar-Corporation/XRT94L33IB-L_datasheet_100163/XRT94L33IB-L_368.png)
XRT94L33
xr
Rev.1.2.0.
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
368
Note:
The Receive STS-3 TOH Processor block will indicate that it is generating this interrupt by toggling the “INT*”
output pin “l(fā)ow” and by setting the “Change of SD Defect Condition Interrupt Status” bit to “1”, as depicted
below.
Receive STS-3 Transport Interrupt Status Register – Byte 0 (Address = 0x110B)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Change of
SF Defect
Condition
Interrupt
Status
Change of
SD Defect
Condition
Interrupt
Status
Detection of
REI-L Error
Interrupt
Status
Detection of
B2 Byte
Error
Interrupt
Status
Detection of
B1 Byte
Error
Interrupt
Status
Change of
LOF Defect
Condition
Interrupt
Status
Change of
SEF Defect
Condition
Interrupt
Status
Change of
LOS Defect
Condition
Interrupt
Status
RUR
0
1
0
It will set Bit 3 (SD Defect Declared), within the “Receive STS-3 Transport Status Register – Byte 0” to
“1”, as depicted below.
Receive STS-3 Transport Status Register – Byte 0 (Address = 0x1107)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
RDI-L
Defect
Declared
S1 Byte
Unstable
Defect
Declared
K1, K2 Byte
Unstable
Defect
Declared
SF Defect
Declared
SD Defect
Declared
LOF Defect
Declared
SEF Defect
Declared
LOS Defect
Declared
R/O
0
1
0
2.3.1.13.3
The SD (Signal Degrade) Defect Clearance Criteria
The XRT94L33 permits the user to specify the following two parameters to define the SD Defect Clearance
criteria.
The maximum number of B2 errors (e.g., a B2 byte error-threshold) accumulated over a given “SD Defect
Clear Monitor” time period.
The length of this “SD Defect Clear Monitor” time period.
Once the user defines these parameters, then the Receive STS-3 TOH Processor block will begin to count
the cumulative number of B2 byte errors that it detects within a “sliding window” of time. The length of this
“sliding window of time” is dictated by the user-defined “SD Defect Clear Monitor” time period.
If the Receive STS-3 TOH Processor block is currently declaring the SD Defect condition, and if continues to
detects more than the “SD Defect Clear B2 error threshold” number of B2 errors; within the “SD Defect Clear
Monitor” of time, then it will NOT clear the SD defect condition. Conversely, if the Receive STS-3 TOH
Processor block detects less than the “SD Defect Clear B2 byte error threshold” number of B2 byte errors,
within the “SD Defect Clear Monitor” period of time, then it will clear the SD defect condition.
Specifying the “B2 Byte Error Threshold” for Clearing the SD Defect Condition
The user can specify the “SD Defect Clear B2 Byte Error Threshold” by writing the appropriate value into the
“Receive STS-3 Transport – Receive SD Clear Threshold – Byte 1 and Byte 0” registers, as depicted below.