
xr
XRT94L33
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Rev.1.2.0.
379
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
Condition
Interrupt
Status
Change of
SD
Condition
Interrupt
Status
REI-L Error
Interrupt
Status
B2 Error
Interrupt
Status
B1 Error
Interrupt
Status
Change of
LOF
Condition
Interrupt
Status
SEF
Interrupt
Status
Change of
LOS
Condition
Interrupt
Status
RUR
1
0
It will set Bit 4 (SF Detected) within the “Receive STS-3 Transport Status Register – Byte 0” to “0”,
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
Declared
S1 Unstable
APS
Unstable
SF Detected
SD Detected
LOF Defect
Detected
SEF Defect
Declared
LOS Defect
Declared
R/O
0
SF DECLARATION CRITERIA – per the “Burst” SF Detector
In this case, the user specifies two parameters to define the SF Declaration criteria.
The minimum number of B2 errors (e.g., a B2 error-threshold) accumulated over a given “SF Set Interval”
time period.
The length (in terms of SONET frame periods) of this “SF Set Interval” 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 errors that it detects within a “sliding window” of time. The length of this “sliding
window of time” is dictated by the user-defined “SF Set Interval” time period.
As long as the Receive STS-3 TOH Processor block does not detects the “B2 error threshold” number of B2
errors, within this “SF Set Interval” of time, then it will not declare the SF Condition.
Conversely, if the
Receive STS-3 TOH Processor block detects at least the “B2 error threshold” number of B2 errors, within the
“SF Set Interval” of time, then it will declare the SF Condition.
Specifying the “B2 Error Threshold” for Declaring SF
The user can specify the “B2 Error Threshold” by writing the appropriate value into the “Receive STS-3
Transport – Receive SF Burst Error Tolerance – Byte 1 and Byte 0” registers, as depicted below.
Receive STS-3 Transport – Receive SF Burst Error Tolerance – Byte 1 (Address = 0x1156)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
SF_BURST_TOLERANCE[15:8]
R/W
1