PM7350 datasheet(71/241 Pages) PMC

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RELEASED

PM7350 S/UNI-DUPLEX

DATA SHEET

PMC-1980581

ISSUE 5

DUAL SERIAL LINK PHY MULTIPLEXER

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

Fig. 8 Cell delineation State Diagram

HUNT

PRESYNC

SYNC

correct HCS

(bit by bit)

DELTA

consecutive

correct HCS's

(cell by cell)

Incorrect HCS

(cell by cell)

ALPHA

consecutive

incorrect HCS's

(cell by cell)

The values of ALPHA and DELTA determine the robustness of the delineation

method. ALPHA determines the robustness against false misalignments due to

bit errors. DELTA determines the robustness against false delineation in the

synchronization process. ALPHA is chosen to be 7 and DELTA is chosen to be

The loss of cell delineation (LCD) alarm is declared after a programmable

threshold of incorrect cells occurs while in the HUNT state. The threshold is set

by the Receive Serial LCD Count Threshold register. The threshold has a default

value of 104 which translates to 73 ms at 600 kbs.All idle cells are filtered out

and not passed to the high-speed interface. They are identified as cells

containing all zeros VPI, and VCI fields and a one in the CLP bit. Optionally,

unassigned cells (like idle cells except CLP is a zero) may also be filtered.

All cells with an incorrect HCS octet are filtered out. Header correction is not

implemented.

As an option configured in Receive Serial Indirect Channel Configuration register

(0x69), the ATM Transmission Convergence functions can be disabled to provide

a clear channel capability. In this case, the serial data is segmented into 53 byte

packets independent of the contents, and then transported across the high-

speed LVDS links.

PM7350 Datasheet(PDF) 71 Page - PMC-Sierra, Inc