PM5361TUPP
DATA SHEET
PMC-920526
ISSUE 8
TRIBUTARY UNIT PAYLOAD PROCESSOR
9.3.3 Incoming Multiframe Detector
The incoming multiframe detector frames to the tributary multiframe encoded into
the H4 bytes. It aligns a fly-wheeling multiframe counter to the alignment
indicated by the H4 bytes when confidence is achieved in the H4 bytes. A
change of incoming tributary multiframe occurs when the H4 bytes cycle error
free and in correct sequence for four frames, and the detected alignment is new.
The incoming multiframe detector is disabled and the multiframe is indicated by
the ITMF input signal, when ITMF is enabled through the ITMFEN register bit.
9.3.4 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 buffer for the
tributary in question. A marker that tags the V5 byte (or J1 byte in the case of a
TU3) is passed through the payload buffer. The incoming timing generator
directs the pointer interpreter to the correct payload buffer for the tributary being
processed. Loss of pointer status is captured in microprocessor readable
registers for each tributary and interrupts can optionally be generated upon loss
of pointer and pointer acquisition. The pointer interpreter detects tributary path
AIS and suppresses the loss of pointer indication that would otherwise occur.
The pointer interpreter passes this information to the pointer generator triggering
path AIS insertion into the corresponding outgoing tributary.
The pointer generator can be configured to insert tributary path AIS into outgoing
tributaries if loss of pointer is detected on the associated incoming tributary.
9.3.5 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 (or TU3 J1) 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.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
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PMC [ PMC-SIERRA, INC ]
