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XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER WITH HDLC CONTROLLER
REV. 1.2.1
62
Marker bit-field, then it will write this logic state into Bit 1 (RxTMark) within the Rx E3 Configuration & Status
Register 2 (Address = 0x11)
Writing a "0" into this bit-field causes the Receive DS3/E3 Framer block to validate the Timing Marker value
after receiving 3 consecutive incoming E3 frames, with the Timing Marker bit-field of a given value. Writing a
"1" into this bit-field causes the Receive DS3/E3 Framer block to validate the Timing Marker value after
receiving 5 consecutive incoming E3 frames, with the Timing Marker bit-field of a given value.
N
OTE
:
This bit-field is ignored if the channel is configured to support the October 1998 version of the ITU-T G.832 framing
format for E3.
Bits 2 - 0: RxPLDExp[2:0]
This Read/Write bit-field allows the user to specify the Payload Type that is expected in the MA bytes, of each
incoming E3 frame.
If the Receive DS3/E3 Framer detects a Payload Type that differs from the values within these bit-fields, then
the Framer will generate the Payload Type Mismatch interrupt.
2.3.3.2
Receive E3 Configuration & Status Register 2 (E3, ITU-T G.832)
Bit 7 - RxLOF Algo (Loss of Frame Declaration Algorithm)
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 currently 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 experiencing 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 experiencing 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 experiencing 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 declared, and is continuing to experience an LOS condition. 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 Declaration)
This Read-Only bit-field indicates whether or not the Receive DS3/E3 Framer block is currently experiencing
an AIS condition. The Receive DS3/E3 Framer block will declare an AIS condition if it has detected two
RxE3 Configuration & Status Register 2 (Address = 0x11)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
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
0
0
1
0