XRT72L13 Datasheet, PDF (307/370 Pages) Exar Corporation – M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC

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PRELIMINARY
XRT72L13
M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC
REV. P1.0.6
"RX DS3 CONFIGURATION AND STATUS" REGISTER, (ADDRESS = 0X10)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT2
BIT 1
BIT 0
Rx AIS
Rx LOS
Rx Idle
Rx OOF
Reserved
Framing on
Parity
F-Sync
Algo
M-Sync
Algo
RO
RO
RO
RO
R/W
R/W
R/W
R/W
X
X
X
X
X
X
X
X
Table 32 relates the contents of this bit-field to the
"OOF Declaration" criteria
TABLE 32: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 1 (F-SYNC ALGO) WITHIN THE RX DS3
CONFIGURATION AND STATUS REGISTER, AND THE RESULTING "F-BIT OOF DECLARATION CRITERIA" USED BY THE
"RECEIVE DS3 FRAMER" BLOCK
F-SYNC ALGO (BIT 1)
0
1
OOF DECLARATION CRITERIA
"OOF" is declared when 6 out of 16 consecutive F-bits are in error.
"OOF" is declared when 3 out of 16 consecutive F-bits are in error.
NOTE: Once the "Receive DS3 Framer" block has declared
an "OOF" condition, it will transition back to the "F-Bit
Search" state within the "DS3 Frame Acquisition/Mainte-
nance" algorithm (per Figure 100 ).
In addition to selecting an "OOF Declaration" criteria
for the F-bits, the user has the following options for
configuring the "OOF Declaration" criteria based up-
on M-bits.
1. M-bit errors do not cause a "OOF" Declaration, or
2. "OOF" will be declared if 3 out of 4 consecutive
M-bits are in error.
The user will select between these two options by
writing the appropriate value to Bit 0 (M-Sync Algo)
within the "Receive DS3 Configuration and Status"
Register; as depicted below.
RX DS3 CONFIGURATION AND STATUS REGISTER, (ADDRESS = 0X10)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT2
BIT 1
BIT 0
Rx AIS
Rx LOS
Rx Idle
Rx OOF
Reserved
Framing on
Parity
F-Sync
Algo
M-Sync
Algo
RO
RO
RO
RO
R/W
R/W
R/W
R/W
X
X
X
X
X
X
X
X
Table 33 relates the contents of this Bit Field to the
"M-Bit Error" criteria for Declaration of OOF.
TABLE 33: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 0 (M-SYNC ALGO) WITHIN THE "RX DS3
CONFIGURATION AND STATUS" REGISTER, AND THE RESULTING "M-BIT OOF DECLARATION CRITERIA" USED BY THE
"RECEIVE DS3 FRAMER" BLOCK
MSYNC ALGO
0
1
OOF DECLARATION CRITERIA
M-Bit Errors do not result in the declaration of "OOF"
"OOF" is declared when 3 out of 4 M-bits are in error.
The "Framing on Parity" Criteria for OOF Declara-
tion
Finally, the Framer IC offers the "Framing on Parity"
option, which also effects the "OOF Declaration" cri-
teria. As was mentioned earlier, the Framer IC allows
the user to configure the "Receive DS3 Framer" block
to detect 'valid-parity' before declaring itself "In-
Frame". This same selection also configures the "Re-
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