DocID024408 Rev 2

17/21

AN4276

Application software notes

5.3.1

Check ECC immediately after each read access

Figure 9. Example of Immediate ECC check during read function

Advantage

Recognition of corrupted data in the Flash memory is immediate after the first read access.

It can help to decrease time in the case where a lot of memory words are corrupted, like

power drop during sector erase operation.

Disadvantage

ECC check needs some processing time for each read access. This increases processing

time of read operation in general.

5.3.2

Check ECC after whole data buffer is read

Figure 10. Example of ECC check after whole buffer is read

Advantage

Standard read buffer operation is not delayed with ECC check after each read access. This

gives the standard performance in case of good memory sector.

ReadBuffer ()

error = 0;

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

{

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

if (MCR.EER == 1)

{

error

= 1;

break ;

}

}

if (error )

{

DoErrorAction ();

end funciton ;

}

...

IVOR 2 Handler

if (ECSM.FNCE)

{

if (DataFlash

== TRUE)

{

SRR 0 <= change to next instruction

;

return from Handler

;

}

}

1x time

ReadBuffer ()

error = 0;

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

{

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

}

if (MCR.EER)

{

DoErrorAction ();

end funciton ;

}

...

IVOR 2 Handler

if (ECSM.FNCE)

{

if (DataFlash

== TRUE)

{

SRR 0 <= change to next instruction

;

return from Handler

;

}

}

i times