PM8621 PMC-Sierra, Inc., PM8621 Datasheet - Page 44

• Manufacturer Part Number: PM8621
• Description: NSE-8G Standard Product Data Sheet Preliminary
• Manufacturer: PMC-Sierra, Inc.

9.3
9.3.1
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010850, Issue 1
Transmit 8B/10B Encoder (T8TE)
The Transmit 8B/10B Encoder blocks, T8TE, construct an 8B/10B character stream from an
incoming translated SBI336 or TelecomBus carrying an STS-12/STM-4 equivalent channelized
stream. The T8TE block corrects the running disparity of an 8B/10B character stream and buffers
data in a FIFO before transmission to the transmit serializer block. A total of 32 T8TE blocks are
instantiated in the NSE-20G device.
In SBI mode, these blocks encode the SBI336S stream as shown in Table 2. 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 four frames.
Table 2 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 2 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-
Synchronous T1/E1 Links
K27.7-
Asynchronous DS3/E3 Links
K27.7-
K28.7-
K29.7-
Fractional Rate Links
K28.7-
SBI336S 8B/10B Character Encoding
Curr. RD-
abcdei fghj
001111 1010
111010 1000
110110 1000
001111 1000
101110 1000
110110 1000
110110 1000
001111 1000
101110 1000
001111 1000
Curr. RD+
abcdei fghj
110000 0101
-
-
-
-
-
-
-
-
-
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
V5 byte
V5 byte, no justification request
V5 byte, negative justification request*
V5 byte, positive justification request*
V5 byte, send one extra byte request**
NSE-8G™ Standard Product Data Sheet
Preliminary
43