PM5347 datasheet(84/302 Pages) PMC

84 / 302 page

PM5347 S/UNI-PLUS

DATA SHEET

PMC-941033

ISSUE 6

SATURN USER NETWORK INTERFACE PLUS

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE

The TMR handles the incoming 16-byte message by synchronizing to the

byte with the most significant bit set high, and places that byte in the first

location in the capture page of the internal RAM. In the case of the 64-byte

message, the TMR synchronizes to the trailing carriage return (0x0D), line

feed (0x0A) sequence and places the next byte in the first location in the

capture page of the internal RAM. The Framer block maintains an internal

representation of the resulting 16-byte or 64-byte "frame" cycle. If the phase

of the start of frame shifts, the framer adjusts accordingly and resets the

persistency counter and increments the unstable counter.

Frame synchronization may be disabled, in which case the RAM acts as a

circular buffer.

Persistency:

The Persistency process checks for repeated reception of the same 16-byte

or 64-byte trace message. An unstable counter is incremented for each

message that differs from the previous received message. For example, a

single corrupted message in a field of constant messages causes the

unstable count to increment twice, once on receipt of the corrupted message,

and again on the next (uncorrupted) message. A section/path trace message

unstable alarm is declared when the count reaches eight.

The persistency counter is reset to zero, the unstable alarm is removed, and

the trace message is accepted when the same 16-byte or 64-byte message is

received three or five times consecutively (as determined by an internal

comparison with the expected message.

Compare:

A receive trace message mismatch alarm is declared if the accepted

message (i.e. the message that passed the persistency check) does not

match the expected message (previously downloaded to the receive expected

page by the microprocessor). The mismatch alarm is removed if the accepted

message is all-zero, or if the accepted message is identical to the expected

message.

2. Overhead Byte Receiver:

The Overhead Byte Receiver (OBR) processes the path signal label byte

(C2). The OBR consists of two sub-processes: Persistency and Compare.

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