PM8611-BIAP PMC [PMC-Sierra, Inc], PM8611-BIAP Datasheet - Page 56

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

10.7.2
10.8
10.8.1
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010883, Issue 2
PRBS Detector
The PRBS detector sub-block monitors the SPE bytes in the incoming data stream. The incoming
data is compared against the expected value derived from an internal linear feedback shift register
(LFSR) with a polynomial of X
value for three consecutive bytes, the PRBS detector sub-block will enter out-of-synchronization
(OOS) state. The LFSR will be re-initialized using the incoming data bytes. The new LFSR seed
is confirmed by comparison with subsequent incoming data bytes. The PRBS detector sub-block
will exit the OOS state when the incoming data matches the LFSR output for three consecutive
bytes. The PRBS detector sub-block will remain in the OOS state and re-load the LFSR if
confirmation failed. The PRBS sub-block counts PRBS byte errors and optionally generates
interrupts when it enters and exits the OOS state.
Transmit 8B/10B Encoders
The Transmit 8B/10B Encoder blocks, TW8E and TP8E, construct an 8B/10B character stream
from an incoming translated SBI336 bus or TelecomBus carrying an STS-12/STM-4 equivalent
stream.
In SBI mode, these blocks encode the SBI336S stream as shown in Table 21. When configured
for Synchronous mode for DS0 switching, the 8B/10B encoder transmits CAS signaling
multiframe alignment across the SBI336S interface by generating a C1FP character every 48
frame times. When not configured for DS0 switching the C1FP character is sent every 4 frames.
SBI336S 8B/10B Character Encoding
Table 21 shows the mapping of SBI336S bus control bytes and signals into 8B/10B control
characters. The linkrate octet in location V4, V1 and V2, the in-band programming channel, the
V3 octet when it contains data are all carried as data. Justification requests for master timing are
carried in the V5 character so there are three V5 characters used, nominal, negative timing
adjustment request, positive timing adjustment request.
Table 21 SBI336S Character Encoding
Code Group
Name
Common to All Link Types
K28.5
K23.7-
Asynchronous T1/E1 Links
K27.7-
K28.7-
K29.7-
Curr. RD-
abcdei fghj
001111 1010
111010 1000
110110 1000
001111 1000
101110 1000
23
+ X
18
Curr. RD+
abcdei fghj
110000 0101
-
-
-
-
+ 1. If the incoming data fails to match the expected
SBSLITE™ Telecom Standard Product Data Sheet
Encoded Signals
Description
IC1FP=’b1
C1FP frame and multiframe alignment
Overhead Bytes (columns 1-60 or 1-72
except for C1 and in-band programming
channel), V3 or H3 byte except during
negative justification, byte after V3 or H3
byte during positive justification, unused
bytes in fraction rate links
V5 byte, no justification request
V5 byte, negative justification request
V5 byte, positive justification request
Preliminary
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