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XRT79L71
PRELIMINARY
381
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
5.3.2.3.1
Declaring the LOS Defect Condition
The Receive E3 Framer block will declare the "Loss of Signal" (LOS) Defect condition when it detects at least
32 consecutive "0s" within the incoming E3 data-stream, or if the Receive DS3/E3 LIU Block declares the LOS
defect condition. The Receive E3 Framer block will indicate that it is declaring the LOS defect condition by
doing all of the following.
Setting Bit 4 (LOS Defect Declared) within the Receive E3 Configuration and Status Register # 2", to "1" as
depicted below.
The Receive E3 Framer block will also generate the "Change of LOS Defect Condition" Interrupt request by
asserting the Interrupt Output pin (e.g., by pulling it "LOW") and setting Bit 1 (Change in LOS Defect
Condition Interrupt Status), within the Receive E3 Interrupt Status Register # 1" to "1" as depicted below.
NOTE:
The LOS Defect Declaring Criteria for the Receive DS3/E3 LIU Block will be discussed in SEE”THE LOS 5.3.2.3.2
Clearing the LOS Defect Condition
The Receive E3 Framer block will clear the "LOS Defect" condition when both of the following conditions are
met.
a. When the Receive E3 Framer block (while declaring the LOS Defect Condition) receives a stream of 32
consecutive E3 bits, which does not contain a string of four (4) consecutive "0s".
b. When the Receive DS3/E3 LIU Block clears the LOS defect condition.
The Receive E3 Framer block will indicate that it is clearing the LOS defect condition by:
Setting Bit 4 (LOS Defect Condition Declared) within the Receive E3 Configuration and Status Register # 2"
to "0" as depicted below.
Receive E3 Configuration and Status Register # 2 - G.751 (Address = 0x1111)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Receive
LOF
Algo
LOF
Defect
Condition
Declared
OOF
Defect
Condition
Declared
LOS
Defect
Condition
Declared
AIS Defect
Condition
Declared
Unused
FERF/RDI
Defect
Condition
Declared
R/W
R/O
X
0
1
0
Receive E3 Interrupt Status Register # 1 - G.751 (Address = 0x1114)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
COFA
Interrupt
Status
Change in
OOF Defect
Condition
Interrupt
Status
Change in
LOF Defect
Condition
Interrupt
Status
Change in
LOS Defect
Condition
Interrupt
Status
Change in
AIS Defect
Condition
Interrupt
Status
R/O
RUR
0
1
0