XRT72L56 Datasheet, PDF (126/486 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
2.4.6.1 Transmit E3 Configuration Register
(E3, ITU-T G.832)
TXE3 CONFIGURATION REGISTER (ADDRESS = 0X30)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
Not Used
TxDL
in NR
Not Used
RO
RO
RO
R/W
RO
0
0
0
0
0
BIT 2
TxAIS
Enable
R/W
0
áç
PRELIMINARY
BIT 1
TxLOS
Enable
R/W
0
BIT 0
TxMARx
R/W
0
Bit 4 - DLinNR
This Read/Write bit-field permits the user to specify
whether the LAPD Transmitter should insert the out-
bound LAPD Message frame octets into the NR byte-
field, or in the GC-byte-field, within each outbound E3
frame.
Writing a "1" configures the LAPD Transmitter to in-
sert the octets of the outbound LAPD Message frame
into the NR byte-field, within each outbound E3
frame. Writing in "0" configures the LAPD Transmitter
to insert the octets of the outbound LAPD Message
frame into the GC byte-field, within each outbound E3
frame.
Bit 2 - TxAIS Enable
This Read/Write bit-field allows the user to command
the Transmit E3 Framer to transmit an AIS pattern,
upon demand.
Writing a "0" to this bit-field allows the Transmit DS3/
E3 Framer block to transmit internally generated data
(e.g., the ITU-T G.832 compatible E3 frames with the
E3 payload data) to the Remote Terminal. Writing a
"1" to this bit-field causes the Transmit DS3/E3 Fram-
er block to transmit an all "1’s" pattern to the Remote
Terminal.
NOTE: If the Transmit DS3/E3 Framer block is transmitting
an AIS pattern to the Remote Terminal, then it is not trans-
mitting any E3 frames. Consequently, if this command is
invoked, the Remote Terminal will experience an OOF (Out
of Frame) condition.
Bit 1 - TxLOS Enable
This Read/Write bit-field allows the user to command
the Transmit E3 Framer to transmit an LOS pattern,
upon demand.
Writing a "0" to this bit-field allows the Transmit E3
Framer to transmit internally generated data (e.g., the
ITU-T G.832 compatible E3 frames with ATM cell da-
ta) to the Remote Terminal. Writing a "1" to this bit-
field causes the Transmit DS3/E3 Framer block to
transmit an "All 0’s" pattern to the Remote Terminal.
NOTE: If the Transmit DS3/E3 Framer block is transmitting
an LOS pattern to the RemoteTerminal, then it is not trans-
mitting any E3 frames. Consequently, the Remote Terminal
will experience an LOS (Loss of Signal) and OOF (Out of
Frame) condition.
Bit 0 - MARx (FERF and FEBE bit-field Loopback)
This Read/Write bit-field allows the user to specify
whether the value of the FERF and FEBE bit-fields, in
the outbound E3 frames, should be based upon Re-
ceive DS3/E3 Framer conditions or upon the content
of the Tx MA Byte register (Address = 0x2A).
FERF and FEBE values are based upon Receive E3
Framer Conditions
If the user selects Receive DS3/E3 Framer condi-
tions, then the Transmit DS3/E3 Framer block will set
and clear the FERF and FEBE bit-fields in response
to the following conditions.
a. FERF Bit-field
If the Receive DS3/E3 Framer block (in the same
channel) is currently experiencing an LOS, AIS, or
LOF condition, then the Transmit DS3/E3 Framer
block will set the FERF bit-field (in the outbound E3
frame) to "1". Conversely, if the Receive DS3/E3
Framer block is not experiencing any of these condi-
tions, then the Transmit E3 Framer will set the FERF
bit-field (in the outbound E3 frame) to "0".
b. FEBE bit-field
If the Receive DS3/E3 Framer block detects a BIP-8
error in the incoming E3 frame, then the Transmit
DS3/E3 Framer block will set the FEBE bit-field (in
the outbound E3 frame) to "1". Conversely, if the Re-
ceive DS3/E3 Framer block does not detect a BIP-8
error in the incoming E3 frame, then the Transmit
DS3/E3 Framer block will set the FEBE bit-field (in
the E3 outbound E3 frame) to "0".
FEBE and FERF values are based upon the contents
of the Tx MA Byte register
If the user selects the contents of the Tx MA Byte reg-
ister, then whatever value has been written into bit 7
(FERF), within the Tx MA Byte register (Address =
107