peb3456e Infineon Technologies Corporation, peb3456e Datasheet - Page 81

• Manufacturer Part Number: peb3456e
• Description: Channelized T3 Termination, With Ds3 Framer, M13 Multiplexer, T1/e1 Framers And 256-channel Hdlc/ppp Controller
• Manufacturer: Infineon Technologies Corporation

Frame 1 is transmitted first. Bit 1 (most significant bit) of each frame is transmitted first.
4.6.2.1
The F-bit of every fourth frame forms the pattern 001011. This multiframe alignment
allows to identify where each particular frame is located within the multiframe in order to
extract the cyclic redundancy check code (CRC-6) and the data link information.
In the synchronous state two errors within 4 or 5 framing bits, two or more erroneous
framing bits within one ESF multiframe or 4 consecutive errored multiframes will lead to
the asynchronous state.
There are two multiframe synchronization modes selectable via RFMR.SSP:
0
1
4.6.2.2
Generation
In calculating the CRC-6 bits, the F-bits are replaced by binary 1s. All information in the
other bit positions will be identical to the information in the corresponding multiframe bit
positions.
The CRC-6 bit sequence c1, c2, c3, c4, c5, c5 and c6 calculated on multiframe N is
transmitted in multiframe N+1. This CRC polynomial is defined as the remainder after
Data Sheet
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In the synchronous state, the setting of RCMDR.FRS resets the synchronizer
and initiates a new frame search. The synchronous state will be reached again,
if there is only one definite framing candidate. In the case of repeated apparent
simulated candidates, the synchronizer remains in the asynchronous state.
In asynchronous state, setting bit RCMDR.FRS induces the synchronizer to
lock onto the next available framing candidate if there is one. At the same time
the internal framing pattern memory will be cleared and other possible framing
candidates are lost.
In the synchronous state, the setting of RCMR.FRS resets the synchronizer and
initiates a new frame search. Synchronization is achieved if there is only one
definite framing candidate AND the CRC-6 checksum is received without an
error. If the CRC-6 check failed on the assumed framing pattern the TE3-
CHATT will stay in the asynchronous state, searching for an alternate framing
pattern.
In case no alternate framing pattern can be found, setting bit RCMDR.FRS
starts a totally new multiframe search. At the same time the internal framing
pattern memory will be cleared and other possible framing candidates are lost.
Multiframe Synchronization Procedure of the Receiver
CRC-6 Generation / Check according to ITU-T G.706
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Functional Description
PEB 3456 E
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05.2001