SA9101 datasheet(16/40 Pages) SAMES

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Synchronization procedure

Multiframe alignment is assumed to have been lost if double-frame alignment has been

lost or 2 consecutive multiframe patterns are received with an error.

The multiframe re-synchronization procedure starts when doubleframe alignment has

been regained. It may also be invoked by the user through the µP-interface. The CRC

checking mechanism will be enabled after the second correct multiframe pattern has

been found. However, CRC errors will not be counted in unsynchronized state.

The (multiframe) synchronized state is reached after detecting two correct multiframe

alignment patterns in multiframe n and multiframe n+1. The CRC4 flag SR0B1 will be

reset. Resynchronization starts whenever two consecutive multiframes are received

with incorrect multiframe alignment pattern.

Sub-

Frame

Bits 1 to 8 of the frame

Multiframe

No.

Multiframe

i*1

i*:

Spare bits for international use.

Access to received information via µP-

interface. (For transmission, automatic transmission of sub-multiframe error

or insertion through µP-interface is selectable).

n :

Spare bits for national use. Additionally, the 5-byte stacks for receive and

transmit are provided.

C1..C4: Cyclic Redundancy Check bits.

A :

Remote Alarm Indication.

Table 2: CRC-Multiframe Structure

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