keeping data in flash on fixed address

[wim]

Hi,

with the pstorage library, is it possible to store data at a specific flash address? The background of the question is that I would like to store data in flash, and be able to access it again after a power cycle, e.g. when the batteries need to be replaced.

Also, I would like to keep the data even if a software update is done via the DFU boot loader.

How is that done?

Wim

[Stefan Birnir Sverrisson]

Hi Wim

This thread tells something about where data is actually stored in flash when using pstorage. Another option is to use pstorage in RAW mode where you write directly to addresses in the memory space.

If you use bootloader, you need to configure the bootloader so it does not overwrite any application data stored in flash. The application data space is reserved with modifying the constant DFU_APP_DATA_RESERVED in dfu.types.h

[Stefan Birnir Sverrisson]

The block size is limited to the page size, see this thread. I suspect defining more amount of blocks will consume slightly more RAM as you need one identifier for each block. I have not seen any limitation on the number of blocks you can have in total. The block size just need to be word aligned, i.e. with size 4, 8, 12, 16, ... etc. Defining more blocks will however not consume more flash.