Emulating PIC EEPROM "self write to ROM"

[Guest]

Hi !


Many new PICs got no EEPROM, but they got so called "self write" function. So far, as I understand it is method to write data into PIC flash program memory (ROM). I've seen data sheets called emulating EEPROM, I may guess it is what it is called.

Feel free to correct me if I'm wrong, because I feel like it is new for me and I do not know much about it.

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My application needs are: store setup data from UI (may get changed few times) to avoid setup data loss after power off.

- Where I can find good, well formed examples about writing and reading data to ROM.

- How I can allocate or isolate constant space in ROM for data.


Thank you in advance !

[FvM]

[Ttelmah]

Remember:
1) A 'const' value, is put into ROM for you.
2) You can find the real address of the actual data (as opposed to the loader code), with the 'label_address' function.
3) The basic program memory functions as Fvm says, are used in the standard bootloader code.
4) The addressmod operator, allows you to use sections of program memory, and automatically read/write variables stored here.
Remember though the 'write life' limitations of this memory...

Best Wishes

[Guest]

FvM and Ttelmah, Thank You very much !

So...
It is very easy to speak from my point of view.
If i want to store 10 floating point variables (converted into 40 int8s), written into program code at the programming moment as "default values" into certain constant 40 addresses. After programming application user can change tease values at least 100 times ?


By using boot-loader application functions like:
write_program_memory( address, dataptr, count );
It could be done without big fuzz.

Btw. Does a boot-loader integration to a already written program require major changes in program ?

[FvM]