Application software notes

AN4276

18/21

DocID024408 Rev 2

Disadvantage

Any read access with ECC error generates low level exception that runs on background so

many times as there are items in the loop. It can have impact on time needed for initial read

of a sector with many corrupted cells.

5.3.3

Low level exception handler link to the driver ECC check

Figure 11. Example of Low level link to the driver ECC check

Advantage

In case of an ECC error during read access, code execution of Read function immediately

moves to ECC check part, which should find that the data are corrupted. There is the same

performance during errorless operation as well as with ECC errors.

Disadvantage

Because of using exported symbol in the low level exception handler, this symbol should be

unique in the whole application. It means that there is only one place in the application and

the driver that read from the Flash memory.

ReadBuffer ()

error = 0;

for (i=0; i < length ; ++i)

{

buffer [i] = *( mem_ptr + i);

}

ECC_check :

if (MCR.EER)

{

DoErrorAction ();

end funciton ;

}

...

IVOR 2 Handler

if (ECSM.FNCE)

{

if (DataFlash

== TRUE)

{

SRR 0 <= change address to ECC _check symbol ;

return from Handler

;

}

}

1x time