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PRELIMINARY
XRT79L71
382
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
The Receive E3 Framer block will also generate the "Change of LOS Defect Condition" Interrupt 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 Configuration and Status Register # 2" to "1" as depicted below.
Configuration Options for the LOS Declaration/Clearance Criteria
The Receive DS3/E3 Framer block (within the XRT79L71) permits the user to change the "LOS Declaration
criteria" such that the LOS defect condition is declared only if the Receive DS3/E3 LIU Block declares the LOS
defect condition. If the configuration selection is implemented, then the "internally-generated" LOS criteria of
"32 consecutive 0s" will be disabled. The user can accomplish this configuration selection by writing a "0" to
Bit 5 (Internal LOS Enable) within the "Framer Operating Mode Register" as depicted below.
5.3.2.3.3
The Relationship between the LOS Defect Condition being declared and cleared in the
Receive DS3/E3 LIU Block and in the Receive DS3/E3 Framer Block
5.3.2.4
DECLARING AND CLEARING THE AIS DEFECT CONDITION
The Receive DS3/E3 Framer block has the responsibility for declaring and clearing the AIS (Alarm Indication
Signal) defect, as described 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
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
Framer Operating Mode Register (Address = 0x1100)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Local
Loop Back
IsDS3
Internal
LOS
Enable
RESET
Direct
Mapped
ATM
Frame
Format
TimRefSel[1:0]
R/W
0
1
0
1