PMC-Sierra, Inc.
PRELIMINARY
PM5381 S/UNI-2488
DATASHEET
PMC-2000489
ISSUE 1
SATURN USER NETWORK INTERFACE FOR 2488 MBIT/S
characters. The character alignment block also monitors for line-code violations (LCV) which are
accumulated in an internal register. If 5 or more LCVs are detected within a window of 15
characters, the R8TD will enter the out-of-character-alignment state and begin searching for the
K28.5 character afresh.
When operating in FIFO mode, aligned characters are written into a 24-character FIFO that
isolates the incoming timing domain from the outgoing timing domain and provides a means of
synchronizing multiple R8TDs outputs. Otherwise, the FIFO is bypassed.
In order to allow synchronization with other R8TDs that may have slightly different frame
alignment and to allow for frame re-alignment, the R8TD frame alignment block monitors the
character aligned data stream for the K28.5. An internal frame counter is maintained based on
this character. If the K28.5 is found out of place three times then the frame alignment moves to
the out-of-frame-alignment state. When in the out-of-frame-alignment state the first K28.5 will be
written to the 0 position of the FIFO. The read pointer is then set by the OJ0FP signal to
synchronize the output of the K28.5 characters which ensures that signals leaving the multiple
R8TDs will have the same alignment.
The R8TD decodes 8B/10B control characters associated with specific SONET/SDH byte
positions in an extended TeleCombus stream. In order to identify more SONET/SDH bytes than
the 12 control characters available in the standard set, those control characters with balanced line
codes for both positive and negative running disparity (K28.0, K28.4, K38.7, K23.7, K27.7, K29.7
and K30.7) are treated specially, where the positive and negative disparity codes are each
associated with a different SONET/SDH byte. The reception of these line-codes will not be
considered LCVs due to a mismatch with the running disparity.
The R8TD provides a diagnostic loopback port where the outgoing stream from an associated
Transmit 8B/10B Encoder block (T8TE) can be processed in place of the incoming stream.
12.1.5 Transmit 8B/10B TeleCombus Encoder (T8TE)
The T8TE encodes a TeleCombus data stream and encodes it into an extended 8B/10B format
for transmission on the serial LVDS links. The T8TE encodes TeleCombus control signals such
as transport frame and payload boundaries, pointer justification events and alarm conditions into
three levels of extended set of 8B/10B characters as well as performing the IEEE mode
conversion on data. In order to identify more TeleCombus bytes and events than the 12 control
characters available in the standard set, those control characters with balanced line codes for
both positive and negative running disparity (K28.0, K28.4, K28.5, k28.6, k28.7, K23.7, K27.7,
K29.7 and K30.7) are treated specially. The positive and negative disparity codes are each
associated of a different SONET/SDH byte or event.
The T8TE can be configured to operate in the Loopback mode which allows a line loopback from
the associated R8TD block. The T8TE can be configured to use a FIFO to bridge between the
incoming data stream and the outgoing data stream clock domains.
Proprietary and Confidentail to PMC-Sierra Inc., and for its Customer’s Internal Use
432
PMC [ PMC-SIERRA, INC ]
