peb2256 Infineon Technologies Corporation, peb2256 Datasheet - Page 292

• Manufacturer Part Number: peb2256
• Description: E1/t1/j1 Framer And Line Interface Component For Long And Short Haul Applications
• Manufacturer: Infineon Technologies Corporation

LFA
RRA
Data Sheet
Loss of Frame Alignment
This bit is set after detecting 3 or 4 consecutive incorrect FAS words
or 3 or 4 consecutive incorrect service words (can be disabled). With
the rising edge of this bit an interrupt status bit (ISR2.LFA) is set. The
specification of the loss of synchronization conditions is done by bits
RC0.SWD and RC0.ASY4. After loss of synchronization, the frame
aligner resynchronizes automatically.
The following conditions have to be detected to regain synchronous
state:
The bit is cleared when synchronization has been regained (directly
after the second correct FAS word of the procedure described above
has been received).
If the CRC-multiframe structure is enabled by setting bit FMR2.RFS1,
multiframe alignment is assumed to be lost if pulseframe
synchronization has been lost. The resynchronization procedure for
multiframe alignment starts after the bit FRS0.LFA has been cleared.
Multiframe alignment has been regained if two consecutive CRC-
multiframes have been received without a framing error (refer to
FRS0.LMFA).
The bit is set during alarm simulation and reset if FMR0.SIM is
cleared and no alarm condition exists.
If bit FRS0.LFA is cleared a loss of frame alignment recovery interrupt
status ISR2.FAR is generated.
Receive Remote Alarm
Set if bit 3 of the received service word is set. An alarm interrupt status
ISR2.RA can be generated if the alarm condition is detected.
FRS0.RRA is cleared if no alarm is detected. At the same time a
remote alarm recovery interrupt status ISR2.RAR is generated.
The bit RSW.RRA has the same function.
Both status and interrupt status bits are set during alarm simulation.
– The presence of the correct FAS word in frame n.
– The presence of the correct service word (bit 2 = 1) in frame n+1.
– For a second time the presence of a correct FAS word in frame
n+2.
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FALC56 V1.2
E1 Registers
PEB 2256
2002-08-27