PM8621 PMC-Sierra, Inc., PM8621 Datasheet - Page 49

• Manufacturer Part Number: PM8621
• Description: NSE-8G Standard Product Data Sheet Preliminary
• Manufacturer: PMC-Sierra, Inc.

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010850, Issue 1
The frame alignment state machine establishes frame alignment over the link and is based on the
frame and not the multiframe alignments. When the frame alignment state machine is in the out-
of-frame-alignment state, it maintains the current alignment, while searching for a C1FP
character. When it finds the C1FP character the state machine transitions to the in-frame-
alignment state. While in the in-frame-alignment state, the state machine monitors out-of-place
C1FP characters. Out-of-place C1FP characters are identified by maintaining a frame counter
based on the C1FP character. The counter is initialized by the C1FP character when in the out-of-
character-alignment state, and is unaffected in the in-character-alignment state. If three
consecutive C1FPs have been found that do not agree with the expected location as defined by the
frame counter, the state will change to out-of-frame-alignment state.
The frame alignment state machine is also sensitive to character alignment. When the character
alignment state machine is in the out-of-character-alignment state, the frame alignment state
machine is forced out-of-alignment, and is held in that state until the character alignment state
machine transitions to the in-character alignment state.
Figure 10 Frame Alignment State Machine
alignment
out-of-
frame-
not (out-of-character alignment)
3 consecutive out-of-place
out-of-character alignment
Found C1FP and
C1FPs or
NSE-8G™ Standard Product Data Sheet
alignment
in-frame-
Preliminary
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