PM7311 pmc-sierra, PM7311 Datasheet - Page 69

• Manufacturer Part Number: PM7311
• Description: Freedm 84a1024l Assp Telecom Standard Datasheet
• Manufacturer: pmc-sierra

Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2021832, Issue 2
10.9 Block Descriptions
10.9.1
10.9.2
Extract Scaleable Bandwidth Interconnect (EXSBI)
The SBI Extract block receives data from the SBI DROP BUS and converts it to an internal
parallel bus format. The SBI Extract block may be configured to enable or disable reception of
individual tributaries within the SBI DROP bus. Individual tributaries may also be configured to
operate in framed or unframed mode. Tributaries may be configured to support channelized
T1/J1/E1 traffic, unchannelized DS3 or Fractional Rate DS3/E3 traffic or unframed traffic at
T1/J1, E1 or DS3 rates.
Receive Channel Assignor (RCAS-12)
The Receive Channel Assignor block (RCAS-12) processes up to 84 links. When receiving data
from the SBI blocks, links may be configured to support channelized T1/J1/E1 traffic,
unchannelized DS3 traffic or unframed traffic at T1/J1, E1, DS3 or Fractional DS3 rates. When
receiving data from the RD inputs, links 0, 4 and 8 support unchannelized data at arbitrary rates
up to 52 Mbps.
It should be noted that for every SBI/SPE used as a serial link, the SBI/SPE must be disabled on
the SBI Bus interface and visa versa.
Each link is independent and has its own associated clock. When receiving data from the RD
inputs, the RCAS-12 performs a serial to parallel conversion to form data bytes. The data bytes
are multiplexed, in byte serial format together with data from EXSBI, for delivery to the Receive
HDLC Processor / Partial Packet Buffer block (RHDL-12) at SYSCLK rate. In the event when
multiple streams have accumulated a byte of data, multiplexing is performed on a fixed priority
basis with link #0 having the highest priority and link #332 the lowest.
The 84 RCAS links have a fixed relationship to the SPE and tributary numbers on the SBI DROP
BUS as shown in the following table.
Table 11 SBI SPE/Tributary to RCAS Link Mapping
Links containing a T1/J1 or an E1 stream may be channelized. Data at each time-slot may be
independently assigned to a different HDLC channel. The RCAS-12 performs a table lookup to
SPE
No.
1
1
1
l
l
l
1
SBI
Trib.
No.
1
2
3
28
RCAS
Link
No.
0
12
24
324
FREEDM 84A1024L ASSP Telecom Standard Product Data Sheet
SPE
No.
2
2
2
2
SBI
Trib.
No.
1
2
3
28
RCAS
Link
No.
4
16
28
328
SPE
No.
3
3
3
3
SBI
Trib.
No.
1
2
3
28
Released
RCAS
Link
No.
8
20
32
l
l
l
332
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