XRT72L56 Datasheet, PDF (120/486 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
TRANSMIT DS3 CONFIGURATION REGISTER (ADDRESS = 0X30)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
Tx Yellow
Alarm
Tx X Bits
Tx Idle
Tx AIS
Tx LOS
FERF on
LOS
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
1
BIT 1
FERF on
OOF
R/W
1
BIT 0
FERF on
AIS
R/W
1
Bit 7 - Tx Yellow Alarm
This Read/Write bit-field permits the user to com-
mand the Transmit DS3/E3 Framer block to transmit a
Yellow Alarm (e.g., X bits are all "0") in the outbound
DS3 data stream.
Writing a "0" to this bit-field disables this feature (the
default condition). In this condition, the X-bits in the
out-bound DS3 frame, are internally generated
(based upon receiver conditions).
Writing a "1" to this bit-field invokes this command. In
this condition, the Transmit DS3/E3 Framer block will
override the internally-generated X-bits and force all
of the X-bits of each outbound DS3 frame to "0".
NOTE: For more information in this feature, please see Sec-
tion 3.2.4.2.1.1.
NOTE: This bit-setting is ignored if Bits 3, 4 or 5 (within this
register) are set to "1".
Bit 6 - Tx X-Bit (Force X bits to "1")
This "Read/Write" bit-field permits the user to com-
mand the Transmit DS3/E3 Framer block to force all
of the X-bits, in the outbound DS3 Frames, to "1".
Writing a "0" to this bit-field disables this feature (the
default condition). In this case, the Transmit DS3/E3
Framer block will generate X-bits based upon the re-
ceive conditions.
Writing a "1" to this bit-field invokes this command. In
this case, the Transmit DS3/E3 Framer block will
overwrite the internally-generated X-bits and set them
all to "1".
NOTE: For more information on this feature, please see
Section 3.2.4.2.1.2.
NOTE: This bit-setting is ignored if Bits 3, 4, 5, or 7 (within
this register) are set to "1".
Bit 5 - Tx Idle (Pattern)
This Read/Write bit-field permits the user to com-
mand the Transmit DS3/E3 Framer block to transmit
the Idle Condition pattern. If the user invokes this
command, then the Transmit DS3/E3 Framer block
will force the outbound DS3 Frames to have the fol-
lowing patterns.
• Valid M-bits, F-bits and P-bits
• The three CP-Bits (F-frame #3) are "0"
• The X-bits are set to "1"
• A repeating "1100..." pattern in written into the pay-
load portion of the DS3 Frames.
Writing a "1" to this bit-field invokes this command.
Writing a "0" allows the Transmit DS3/E3 Framer
block to function normally (e.g., the Transmit DS3/E3
Framer block will transmit its payload and internally
generated overhead bits).
NOTE: For more information on this feature, please see
Section 3.2.4.2.1.3.
NOTE: This bit-setting is ignored if Bits 3 or 4 (within this
register) are set to "1".
Bit 4 - Tx AIS (Pattern)
This Read/Write bit-field permits the user to com-
mand the Transmit DS3/E3 Framer block to transmit
an AIS pattern. If the user invokes this command,
then the Transmit DS3/E3 Framer block will force the
outbound DS3 frames to have the following patterns.
• Valid M-bits, F-bits, and P-bits
• All C-bits are set to '0'
• All X-bits are set to '1'
• A repeating '1010...' pattern is written into the pay-
load of the DS3 Frames.
Writing a "1' to this bit-field invokes this command.
Writing a "0" allows the Transmit DS3/E3 Framer
block to function normally (e.g., the Transmit DS3/E3
Framer block will transmit its payload and internally
generated overhead bits).
NOTE: For more information on this feature, please see
Section 3.2.4.2.1.4.
Bit 3 - Tx LOS (Loss of Signal)
This Read/Write bit-field permits the user to com-
mand the Transmit DS3/E3 Framer block to simulate
an LOS Condition. If the user invokes this command,
then the Transmit DS3/E3 Framer block will stop
sending mark pulses out on the line and will transmit
an all-zero pattern.
Writing a '0' to this bit-field disables (or shuts off) this
feature, thereby allowing internally generated DS3
Frames to be generated and transmitted over the line.
101