PM5366-PI datasheet(107/267 Pages) PMC

107 / 267 page

PRELIMINARY

PM5366 TEMAP-84

DATASHEET

PMC-2010672

ISSUE 1

HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER

AND M13 MULTIPLEXER

PROPRIETARY AND CONFIDENTIAL

9.22.1 Incoming Multiframe Detector

The multiframe alignment sequence in the path overhead H4 byte is monitored

for the bit patterns of 00, 01, 10, 11 in the two least significant bits. If an

unexpected value is detected, the primary multiframe will be kept, and a second

multiframe process will, in parallel, check for a phase shift. The primary process

will enter out of multiframe state (OOM). A new multiframe alignment is chosen,

and OOM state is exited when four consecutive correct multiframe patterns are

detected. Loss of multiframe (LOM) is declared after residing in the OOM state

at the ninth H4 byte without re-alignment. In counting to nine, the out of

sequence H4 byte that triggered the transition to the OOM state is counted as

the first. A new multiframe alignment is chosen, and LOM state is exited when

four consecutive correct multiframe patterns are detected. Changes in

multiframe alignments are detected and reported.

9.22.2 Pointer Interpreter

The pointer interpreter is a time-sliced state machine that can process up to 28

independent tributaries. The state vector is saved in RAM as directed by the

incoming timing generator. The pointer interpreter processes the incoming

tributary pointers such that all bytes within the tributary synchronous payload

envelope can be identified and written into the unique payload first-in first-out

buffer for the tributary in question. A marker that tags the V5 byte is passed

through the payload buffer. The incoming timing generator directs the pointer

interpreter to the correct payload buffer for the tributary being processed.

The pointer interpreter processes the incoming pointers (V1/V2) as specified in

the references. The pointer value is used to determine the location of the

tributary path overhead byte (V5) in the incoming TUG3 or STS-1 (AU3) stream.

9.22.3 Payload Buffer

The payload buffer is a bank of FIFO buffers. It is synchronous in operation and

is based on a time-sliced RAM. The three 19.44 MHz clock cycles in each

6.48 MHz period are shared between the read and write operations. The pointer

interpreter writes tributary payload data and the V5 tag into the payload buffer. A

16 byte FIFO buffer is provided for each of the (up to 28) tributaries. Address

information is also passed through the payload buffer to allow FIFO fill status to

be determined by the pointer generator.

PM5366-PI Datasheet(PDF) 107 Page - PMC-Sierra, Inc