ST70135 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST70135' PDF : 29 Pages View PDF
ST70135A
ATM Specific TC Layer Functions
The 2 bytes streams (fast and slow) are received
from the byte-based processing unit. When ATM
cells are transported, this block provides basic cell
functions such as cell synchronization, cell
payload descrambling, idle/unassigned cell filter,
cell Header Error Correction (HEC) and detection.
The cell processing happens according to ITU-T
I.163 standard. Provision is also made for BER
measurements at this ATM cell level. When non
cell oriented byte streams are transported, the cell
processing unit is not active.
Figure 7 : ATM Specific TC Layer Functions
The interface module collects cells (from the
cell-based function module) or a Byte stream
(from the deframer). Cells are stored in FIFO’s
(424 bytes or 8 cell wide, transmit buffers have the
same size), from which they are extracted by 2
interface submodules, one providing a Utopia
level 1 interface and the other a Utopia level 2
interface.Byte stream are dumped on the SLAP
(Synchronous Link Access Protocol) interface.
Only one type of interface can be enabled in a
specific configuration.
From
Generic
TC
FAST
CELL SCRAMBLER
DESCRAMBLER
SYNCHRONIZER
SLOW
CELL SCRAMBLER
DESCRAMBLER
SYNCHRONIZER
HEC
HEC
BER
CELL
INSERTION/
FILTER
CELL
INSERTION/
FILTER
BER
To
Interface
Module
Figure 8 : Interface Module
FAST BYTE STREAM
FAST ATM
From
ATM
TC
SLOW ATM
SLOW BYTE STREAM
SLAP
UTOPIA
LEVEL
1
UTOPIA
LEVEL
2
UTOPIA
LEVEL
1
UTOPIA
LEVEL
2
SLAP
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