Error while writing in to MC9S12NE65 Internal Flash

[Kalyan]

Hi all,

i'm currently working with MC9S12NE64 processor. facing some tipical problem while accessing the internal flash of the processor.

i'm getting some one/two bytes of error writes when i'm writing in to the internal flash. i'm using the software that is provided in AN2720.

the problem that i'm facing is some what stringent. since our product has already completed the development phase and right now in testing phase, we have fabricated quite a number of boards with this processor.

as part of the testing of the functionality of the product, we do test the internal flash. in some processors, i'm getting couple of errornous reads after writing to the internal flash.

is this a known scenario? in the sense, will it happen that some of the processors fail to restore the data that is stored in the internal flash after power cycle???

or there is some bug in the software that is given in the application AN2720!!

i dont suspect the processor, since if the flash is corrupted, this will lead to many errors in the real- time.

some one please guide me regarding the same.

Thanks and regards,

Kalyan Kumar P

Ph: 09886361480

India.

[imajeff]

One thing I thought of is if you don't have the right clock speed settings. Writing with a slightly too fast clock could cause some of the bits to lose the programmed state after some amount of time (which could even be a second if bad enough).

I guess you might not have that problem exactly though, it looks like it's not just some bits becoming "unprogrammed".

Message Edited by imajeff on 04-21-200610:26 AM

[alex_spotw]

Hi :

What kind of test are you doing in the Flash Memory? For how long? How many pages?

And when is the power removed from the boards? I ask this because you might be removing the power too soon, and the flash doesn't have time to finish the writing of the data, therefore, corrupting the flash memory.

Let us know!

Regards,

Alex

[Kalyan]

Hi Alex,

we are using the a part of the flash i.e. 0x4000 to 0x41FF for storing some data base. so that the data is resided even after power re-cycle.

coming to the point, i'm not intending to say that when i do a power re-cycle, the flash is not getting updated. the problem that i'm facing is once i write data in to the flash in to the location that i have specified, when i read the data back, in some processors, one or two bytes are getting corrupted.

let me tell you in detail. what i have faced here in one of the processors is, when i write say some first 200 bytes with 1 to 200 and when i read back after writing, in one of the processors, the 86th byte was getting corrupted. in the sense i'm not getting 86 when i read... but i'm getting 32.  in one more processor board, i got error reading the byte 182.

so, this behaviour is random. and if i have to suspect the code, the same code works fine in many of the processors.

please let me know if you want some more info.

Thanks,

Kalyan kumar P