XRT72L56 Datasheet, PDF (102/486 Pages) Exar Corporation – SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L56 SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
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PRELIMINARY
2.4.3.2 Receive E3 Configuration & Status
Register 2 (E3, ITU-T G.832)
RXE3 CONFIGURATION & STATUS REGISTER 2 (ADDRESS = 0X11)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Rx LOF Algo RxLOF
RxOOF
RxLOS
RxAIS RxPld Unstab RxTMark
RxFERF
R/W
RO
RO
RO
RO
RO
RO
RO
0
1
1
1
1
1
1
1
Bit 7 - RxLOF Algo (Loss of Frame Declaration Al-
gorithm)
This Read/Write bit-field allows the user to select the
LOF (Loss of Frame) Declaration criteria, that will be
used by the Receive DS3/E3 Framer. Writing a "0" to
this bit-field configures the Receive DS3/E3 Framer to
declare an LOF condition, after it has been in the
OOF condition for 24 frame periods (3 ms). Writing a
"1" to this bit-field configures the Receive DS3/E3
Framer to declare an LOF condition, after it has been
in the OOF condition for 8 frame periods (1 ms).
Bit 6 - RxLOF (Loss of Frame Declaration)
This Read-Only bit-field indicates whether or not the
Receive DS3/E3 Framer block is currently in the Loss
of Frame (LOF) condition. If this bit-field is set to "1",
then the Receive DS3/E3 Framer block is currently in
the LOF condition. Conversely, if this bit-field is set to
"0", then the Receive DS3/E3 Framer block is current-
ly not in the LOF condition.
Bit 5 - RxOOF (Out of Frame Declaration)
This Read-Only bit field indicates whether or not the
Receive DS3/E3 Framer block is currently experienc-
ing an Out of Frame (OOF) condition. The Receive
DS3/E3 Framer block will declare an OOF condition if
it has detected errors in the frame alignment bytes
(FA1 and FA2) in four consecutive frames. If this bit-
field is set to "1", then the Receive DS3/E3 Framer
block has declared, and is continuing to experience
an OOF condition. If this bit-field is set to "0", then
the Receive DS3/E3 Framer block is currently not ex-
periencing an OOF condition.
Bit 4 - RxLOS (Loss of Signal Declaration)
This Read-Only bit-field indicates whether or not the
Receive DS3/E3 Framer block is currently experienc-
ing a Loss of Signal (LOS) condition. The Receive
DS3/E3 Framer block will declare an LOS condition if
it has detected a string of 32 consecutive "0’s", via the
RxPOS and RxNEG input pins. If this bit-field is set
to "1", then the Receive DS3/E3 Framer block has de-
clared, and is continuing to experience an LOS condi-
tion. If this bit-field is set to "0", then the Receive
DS3/E3 Framer block is currently not experiencing an
LOS condition.
Bit 3 - RxAIS (Alarm Indication Status Declara-
tion)
This Read-Only bit-field indicates whether or not the
Receive DS3/E3 Framer block is currently experienc-
ing an AIS condition. The Receive DS3/E3 Framer
block will declare an AIS condition if it has detected
two consecutive E3 frames, that each contain less
than seven (7) "0’s" . If this bit-field is set to "1", then
the Receive DS3/E3 Framer block has declared, and
is continuing to experience an AIS condition. If this
bit-field is set to "0", then the Receive DS3/E3 Framer
block is currently not experiencing an AIS condition.
Bit 2 - RxPLDType UnStab
This Read-Only bit-field indicates whether or not the
Receive DS3/E3 Framer block has been receiving a
consistent Payload Type value (within the MA Byte-
Field) in the last 5 consecutive incoming E3 frames.
If the Receive DS3/E3 Framer block has detected a
change in the Payload Type value, within the last 5 in-
coming E3 frames, then it will set this bit-field to "1".
If the Payload Type value has been consistent in the
last 5 E3 frames, then the Receive DS3/E3 Framer
block will set this bit-field to "0".
Bit 1 - Rx TMark
This Read-Only bit-field reflects the most recently val-
idated Timing Marker value. The Receive DS3/E3
Framer block will validate the Timing Marker state, af-
ter it has detected a user-selectable number of con-
secutive incoming E3 frames with a consistent Timing
Marker value. The user makes this selection by writ-
ing the appropriate value to Bit 3 (RxTMarkAlgo) with-
in the Rx E3 Configuration/Status Register (Address
= 0x0E).
Bit 0 - RxFERF (Far End Receive Failure)
This Read-Only bit-field indicates whether or not the
Receive DS3/E3 Framer block is experiencing an
FERF (Far-End-Receive-Failure) condition. The Re-
ceive DS3/E3 Framer block will declare a FERF con-
dition, if it has received a user-selectable number of
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