![](http://datasheet.mmic.net.cn/Exar-Corporation/XRT79L71IB-F_datasheet_100145/XRT79L71IB-F_153.png)
PRELIMINARY
XRT79L71
138
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
NOTES:
1.
In this setting, the Transmit DS3/E3 Framer block will not be setting the C-bits to "0", whenever it is commanded to
transmit the DS3 AIS indicator. This permits the user to still be able to command the Transmit DS3/E3 Framer
block to transmit FEAC and PMDL Messages even while the Transmit DS3/E3 Framer block is also transmitting
the DS3 AIS indicator.
2.
The user can command the Transmit DS3/E3 Framer block to terminate its transmission of the DS3 AIS pattern by
setting Bit 4 (TxAIS) back to "0".
3.
Bit 4 (TxAIS) is ignored for the duration that Bit 3 (TxLOS) is set to "1".
Forcing the transmission of the Unframed, All Ones DS3 AIS pattern, upon Software Control
The user can force the Transmit DS3/E3 Framer block to transmit the Unframed, All Ones DS3 AIS pattern,
upon software command by executing the following steps.
STEP 1 - Set Bit 7 (TxAIS Unframed All Ones), within the Transmit DS3 Pattern Register to "1", as
depicted below.
This step configures the Transmit DS3/E3 Framer block to generate an Unframed, All Ones pattern, whenever
it is commanded to transmit the DS3 AIS indicator.
STEP 2 - Command the Transmit DS3/E3 Framer block to transmit the DS3 AIS indicator.
This is accomplished by setting Bit 4 (Tx AIS) to "1" as depicted below.
NOTES:
1.
The user can command the Transmit DS3/E3 Framer block to terminate its transmission of the DS3 AIS pattern by
setting Bit 4 (TxAIS) back to "0".
2.
Bit 4 (TxAIS) is ignored for the duration that Bit 3 (TxLOS) is set to "1".
Transmit DS3 Configuration Register (Address = 0x1130)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Tx Yellow
Alarm
Tx X-Bits
TxIdle
TxAIS
TxLOS
TxFERF
upon LOS
TxFERF
upon OOF
TxFERF
upon AIS
R/W
0
1
0
1
Transmit DS3 Pattern Register (Address = 0x114C)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
TxAIS
Unframed All
Ones
DS3 AIS
Non-Stuck
Stuff
Unused
TxLOS
Pattern
Transmit_Idle_Pattern[3:0]
R/W
R/O
R/W
1
0
1
0
Transmit DS3 Configuration Register (Address = 0x1130)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Tx Yellow
Alarm
Tx X-Bits
TxIdle
TxAIS
TxLOS
TxFERF
upon LOS
TxFERF
upon OOF
TxFERF
upon AIS
R/W
0
1
0
1