EMX - lose data in flash if backup battery runs out

NETMF & Gadgeteer
1

We used to use ExtendedWeakReference to store small data in flash. Is there any way to avoid data loss if backup battery runs out?

2

EWR does not use any battery.

3

@ Gus -

Hi Gus, what is the max size of data to store in ExtendedWeakReference? or how much space (total size?) could I store data on EMX flash with ExtendedWeakReference?

I checked on EMX manual, it says EMX has 4.5MB flash and 16MB RAM. For example, The total size of GHI EMX 4.1 firmware (CLR.HEX, CLR2.HEX, Config.HEX) is 2.81MB, my application (HEX file) is 3.3MB. How do I calculate the max space of flash space that I could store data with ExtendedWeakReference?

4

EWR is intended to be the place to store just a few settings that need to persist across the power down. Although you haven’t said, it seems to me you might be thinking to use it to store more transitive data, you may not want to do that because it’s still flash and subject to rewrite cycle limits.

5

The llimit given by NXP is 100000 cycles for Flash. However a lot of us are experiencing EWR lost… and as the EWR is a kind of black box to me it will be hard to know the reason of such failure. (size limit. not enough time to strore data…)