XRT79L71 Datasheet, PDF (216/441 Pages) Exar Corporation – 1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

XRT79L71
REV. P1.0.3
4-3
TxNSrcSel[1:0]
2
TxAIS Enable
1
TxLOS Enable
0
TxFAS Source Sel
PRELIMINARY
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1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
R/W
Transmit N Bit Source Select[1:0]:
These two READ/WRITE bit-fields permit the user to specify the
source or type of data that is being carried via the "N" bits, within
each "outbound" E3 data stream, as indicated below.
TxNSrcSel[1:0]
0
0
0
1
1
0
Resulting Source of N Bit
The "TxN" bit-field, within the "TxE3
Service Bit" register (Direct Nddress =
0x1135)
Not Valid - Do not use.
The LAPD Transm itterIn this case, the N
bit will function as the LAPD/PMDL
channel.
The "N" bit is sourced via the "Payload
1
1
Data Input Interface" block. This is
discussed in greater detail in Section _.
R/W Transmit AIS Indicator:
This READ/WRITE bit-field permits the user to (by software con-
trol) force the Frame Generator to generate and transmit the AIS
indicator to the remote terminal equipment.
0 - Does not configure the Frame Generator to generate and
transmit the AIS indicator.
1 - Configures the Frame Generator to generate and transmit the
AIS indicator. In this case, the Frame Generator will force all bits
(within the "outbound" E3 data stream) to an "All Ones" pattern.
NOTE: This bit-field is ignored if the Frame Generator has been
configured to transmit the LOS pattern.
R/W Transmit LOS (Pattern) Enable:
This READ/WRITE bit-field permits the user to (by software con-
trol) force the Frame Generator block to transmit the LOS (Loss
of Signal) pattern to the remote terminal equipment.
0 - Does not configure the Frame Generator block to generate
and transmit the LOS pattern.
1 - Configures the Frame Generator block to generate and trans-
mit the LOS pattern. In this case, the Frame Generator block will
force all bits (within the "outbound" E3 data stream) to an "All
Zeros" pattern.
R/W Transmit FAS Source Select:
This READ/WRITE bit-field permits the user to specify the
source of the FAS (Framing Alignment Signal), to be used in the
"outbound" E3 data-stream, as indicated below.
0 - FAS bits are inserted internally by the Frame Generator block.
1 - FAS bits are sourced by the "Payload Data Input Interface"
block. This is discussed in greater detail in Section _.
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