Embedded application aspects

AN2540 - Application note

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Figure 9.

Sector swap scheme with four sectors

The previous algorithm can be implemented in the FindValidSector(...) function.

4.3

Sector header recovery in case of power loss

Data or sector header corruption is possible in case of a power loss during a variable

update, a sector erase or a transfer.

To detect this corruption and recover it, an initialization routine should be called immediately

after power-up.

After power loss, this routine is used to check the sector header status and to perform repair

if necessary. There are 16 possible status combinations, half of which are invalid. The

following table shows the actions that should be taken based on the sector states upon

power-up.

12

32

DD

AA

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

Active sector

FF

FF

FF

FF

FF FF

FF FF

FF FF

FF FF

FF FF

FF FF

FF FF

FF FF

FF FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

FF

Erased

Erased

Erased

Sector0

Sector1

Sector2

Sector3

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