XRT79L71_1 Datasheet, PDF (220/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
REV. 1.0.0
BIT
NUMBER
NAME
3
FL Alarm Declared
2
Receive LOL
Condition Declared
TYPE
R/O
R/O
DEFAULT
VALUE
0
0
DESCRIPTION
FL (FIFO Limit) Alarm Declared:
This READ-ONLY bit-field indicates whether or not the Jitter
Attenuator block (within the XRT79L71) is currently declar-
ing the FIFO Limit Alarm.
The Jitter Attenuator block will declare the FIFO Limit Alarm
anytime the Jitter Attenuator FIFO comes within two bit-
periods of either overflowing or under-running.
Conversely, the Jitter Attenuator block will clear the FIFO
Limit Alarm anytime the Jitter Attenuator FIFO is NO longer
within two bit-periods of either overflowing or under-running.
Typically, this Alarm will only be declared whenever there is
a very serious problem with timing or jitter in the system.
0 - Indicates that the Jitter Attenuator block (within the
XRT79L71) is NOT currently declaring the FIFO Limit Alarm
condition.
1 - Indicates that the Jitter Attenuator block (within the
XRT79L71) is currently declaring the FIFO Limit Alarm con-
dition.
NOTE: This bit-field is only active if the Jitter Attenuator
(within the XRT79L71) has been enabled.
Receive LOL (Loss of Lock) Condition Declared:
This READ-ONLY bit-field indicates whether or not the
Receive Section (within the XRT79L71) is currently declar-
ing the LOL (Loss of Lock) condition.
The Receive Section (of XRT79L71) will declare the LOL
Condition, if any one of the following conditions is met.
• If the frequency of the Recovered Clock signal differs
from that of the signal provided to the E3CLK input (for
E3 applications) or the DS3CLK input (for DS3
applications) by 0.5% (or 5000ppm) or more.
• If the frequency of the Recovered Clock signal differs
from the line-rate clock signal (for XRT79L71) that has
been generated by the SFM Clock Synthesizer PLL (for
SFM Mode Operation) by 0.5% (or 5000ppm) or more.
0 - Indicates that the Receive Section of XRT79L71 is NOT
currently declaring the LOL Condition.
1 - Indicates that the Receive Section of XRT79L71 is cur-
rently declaring the LOL Condition.
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