
xr
XRT94L33
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Rev.1.2.0.
341
The value that the user writes into these bit-fields reflects the number of STS-3 frame periods that the
Receive STS-3 TOH Processor block must reside within the “SEF = 0, LOF = 1” state and test the Framing
Alignment bytes, within the incoming STS-3 data-stream.
If the Receive STS-3 TOH Processor block does not detect the “User Selectable” number of consecutive “un-
erred” STS-3 frames, then it will remain in the “SEF = 0, LOF = 1” state and will continue to test for the “user-
selectable” number of consecutive un-erred STS-3 frame. If the Receive STS-3 TOH Processor block were to
detect Framing Byte errors in four consecutive STS-3 frames, then it will declare the “SEF” defect and will
transition back into the “SEF = 1, LOF = 1” state.
If the Receive STS-3 TOH Processor block receives this “User-Selectable” number of consecutive “unerred”
STS-3 frames, then it will clear the “LOF defect” and will transition into the “In-Frame” state.
As the Receive STS-3 TOH Processor block transitions from the “SEF = 0, LOF = 1” state to the “In-Frame”
state, it will do all of the following.
It will clear Bit 2 (LOF Defect Declared) 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
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
It will generate the “Change in LOF Defect Condition” interrupt.
The XRT94L33 will indicate that it is
generating this interrupt by doing the following.
a.
Toggling the “INT*” input pin “LOW”.
b.
Setting Bit 2 (Change of LOF Defect Condition Interrupt Status), within the “Receive STS-3
Transport Interrupt Status Register – Byte 0” 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