
á
XRT73L00
E3/DS3/STS-1 LINE INTERFACE UNIT
REV. 1.2.0
36
Monitoring the State of DLOS
If the XRT73L00 is operating in the HOST Mode, the
state of DLOS can be polled or monitored by reading
in the contents of Command Register 0 as shown.
If the DLOS bit-field contains a “1”, the XRT73L00 is
currently declaring a DLOS condition. If the DLOS
bit-field contains a “0”, the device is NOT currently de-
claring the DLOS condition.
Disabling the DLOS Detector
It is useful to disable the DLOS Detector in the
XRT73L00 for debugging purposes. If the XRT73L00
is operating in the HOST Mode, the DLOS Detector
can be disabled by writing a “1” into the DLOSDIS bit-
field in Command Register 2.
N
OTE
:
Setting both the ALOSDIS and DLOSDIS bit-fields
to a “1” disables LOS Declaration in the XRT73L00.
3.6.3
Muting the Recovered Data while the LOS
is being Declared
In some applications it is not desirable for the
XRT73L00 E3/DS3/STS-1 LIU to recover data and
route it to the Receiving Terminal while the LIU is de-
claring an LOS condition. The LOS Muting feature, if
enabled, causes the XRT73L00 to halt transmission
of the recovered data to the Receiving Terminal while
the LOS condition is True. In this case, the RPOS
and RNEG output pins are forced to “0”. Once the
LOS condition has been cleared, the XRT73L00 re-
sumes the transmission of the recovered data to the
Receiving Terminal. The XRT73L00 allows enabling
of the Muting Upon LOS feature by either of the fol-
lowing means.
If the XRT73L00 is Operating in the Hardware
Mode:
The Muting Upon LOS feature is enabled by pulling
the LOSMUTEN input pin (pin 19) to VDD.
If the XRT73L00 is Operating in the HOST Mode:
To enable this feature, access the Microprocessor Se-
rial Interface and write a “1” into the LOSMUT bit-field
in Command Register 3.
N
OTE
:
The XRT73L00 automatically declares an LOS Con-
dition any time it has been configured to operate in either
the Analog Local Loop-Back or Digital Local Loop-Back
Modes. MUTing -upon -LOS must be disabled prior to con-
figuring the device to operate in either of these local Loop-
Back modes.
3.7
R
OUTING
THE
R
ECOVERED
T
IMING
AND
D
ATA
I
NFORMATION
TO
THE
R
ECEIVING
T
ERMINAL
E
QUIPMENT
The XRT73L00 ultimately takes the Recovered Tim-
ing and Data information, converts it into CMOS lev-
els and routes it to the Receiving Terminal Equipment
via the RPOS, RNEG, RCLK1 and RCLK2 output
pins.
The XRT73L00 can deliver the recovered data and
clock information to the Receiving Terminal in either a
Single-Rail or Dual-Rail format.
Routing Dual-Rail Format Data to the Receiving
Terminal Equipment
Whenever the XRT73L00 delivers Dual-Rail format to
the Terminal Equipment it does so via the following
output signals.
RPOS
RNEG
RCLK1
RCLK2
Figure 23 illustrates the typical interface for the trans-
mission of data in a Dual-Rail Format from the Re-
ceive Section of the XRT73L00 to the Receiving Ter-
minal Equipment.
COMMAND REGISTER CR0 (ADDRESS = 0X00)
D4
D3
D2
D1
D0
RLOL
RLOS
ALOS
DLOS
DMO
Read
Only
Read
Only
Read
Only
Read
Only
Read
Only
COMMAND REGISTER CR2 (ADDRESS = 0X02)
D4
D3
D2
D1
D0
Reserved ENDECDIS ALOSDIS DLOSDIS REQDIS
X
X
X
1
X
COMMAND REGISTER CR3 (ADDRESS = 0X03)
D4
D3
D2
D1
D0
RNRZ
LOSMUT
CLK2DIS RCLK2INV CLK1INV
X
1
X
X
X