S12 / MagniV MicrocontrollersのトピックRe: non-volatile Variables - HOW??

non-volatile Variables - HOW??

toebsen — Mon, 12 Oct 2009 15:16:04 GMT

hi there

we have a problem storing variables in the flash of our S12XE100, we do not have any idea how we could achieve it. So Im asking, is there any easy way to save variables non-volatile, like a loader instruction or so? Do we really have to implement the complex way with formating and Emulated EEPROM and stuff? Can you please show us some easy to implement way, perhabs with some code snippets?

Thanks for your time

Regards

toebsen

Re: non-volatile Variables - HOW??

Lundin — Mon, 12 Oct 2009 18:17:22 GMT

Make a memory segment in the .PRM file, then write

#pragma CONST_SEG name_of_segment

const int variable;

#pragma CONST_SEG DEFAULT

Obviously the variables have to be const. I always declare them at file scope too, or the compiler might put them on the stack instead of nvm.

Re: non-volatile Variables - HOW??

jsmcortina — Sat, 17 Oct 2009 02:25:57 GMT

Yes, you need to use emulated EEPROM or come up with an erase/programme scheme for Dflash. Also be aware of what will happen if the power is shut off during a write cycle.

James

Re: non-volatile Variables - HOW??

Lundin — Wed, 28 Oct 2009 19:23:06 GMT

That is only necessary if you want to change the values in runtime. Perhaps the original poster can clarify if that is required by the application or not.