PM8611-BIAP PMC [PMC-Sierra, Inc], PM8611-BIAP Datasheet - Page 55

• Manufacturer Part Number: PM8611-BIAP
• Manufacturer: PMC [PMC-Sierra, Inc]

10.5
10.6
10.7
10.7.1
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010883, Issue 2
CAS Merging
The Channel Associated Signaling Merge blocks, ICASM and OCASM, insert the CAS signaling
information into the SBI bus on a tributary basis. CAS signaling channels within the SBI bus are
constructed out of the available CAS bits for T1 and E1 SBI tributaries that are enabled for CAS
signaling. The resulting CAS signaling channel replaces the octets of the SBI bus where the new
CAS signaling is to be inserted. This block adds one T1 multiframe (24 frames) or one E1
multiframe (16 frames) of latency to the CAS bits.
Incoming SBI336 Tributary Translator
The Incoming SBI336 Tributary Translator block, ISTT, translates all SBI336 timing and
Channel Associated Signaling information for all tributaries into SBI336S format. The output
from this block is a 77.76 MHz SBI336 stream with all tributaries and control signals encoded
into an internal format that closely resembles the serial SBI336S format.
This block translates all tributary types into a form that is easy for the 8B/10B encoder to handle
in a more generic form. A control RAM keeps the current configuration for each of the incoming
SBI bus tributaries so that it can perform the translation function.
Common to all tributaries is identification of the first C1 byte. There are unique mappings of the
8B/10B codes for the supported SBI and SBI336 bus link types: Asynchronous T1/E1,
Synchronous (locked) T1/E1, Transparent VT1.5/VT2, DS3/E3 and Fractional rate links. Much of
the identification and mapping of a link into serial SBI format is based on the C1 frame pulse and
a tributaries location relative to that C1 pulse. In addition to the C1FP identification this block
identifies multiframe alignment, valid payload, pointer movements for floating tributaries and
timing control for encoding into the 8B/10B serial SBI format.
This block is transparent in TelecomBus mode.
PRBS Processors
The Working and Protection PRBS Processor blocks, WPP and PPP, provides in-service and off-
line PRBS generation and detection for diagnostics of the equipment downstream of the two
LVDS links. Each PRBS Processor has the capacity to source and monitor PRBS data for the
associated Working or Protection Serial SBI336S stream with a granularity of unchannelized SBI
SPEs of TelecomBus STS-1s.
PRBS Generator
The PRBS generator sub-block optionally overwrites the data originating from the incoming data
streams, IDATA[4:1][7:0]. When enabled, the PRBS generator sub-block inserts synchronous
payload envelope, SPE bytes into the serial transmit links. The inserted data is derived from an
internal linear feedback shift register (LFSR) with a polynomial of X
SBSLITE™ Telecom Standard Product Data Sheet
23
+ X
18
+ 1.
Preliminary
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