STANDARD PRODUCT
PM5365 TEMAP
DATASHEET
PMC-1991148
ISSUE 3
HIGH DENSITY VT/TU MAPPER
AND M13 MULTIPLEXER
9.15.3 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.
9.15.4 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.
9.15.5 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.
9.15.6 Outgoing Timing Generator
The outgoing timing generator identifies the outgoing tributary byte being
processed. Based on the configuration of the VTPP, the outgoing timing
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PMC [ PMC-SIERRA, INC ]
