[U-Boot-Users] Flash environment vs EEPROM environment

[Roger Larsson <roger.larsson@norran.net>]

On Tuesday 01 February 2005 20.06, Jerry Van Baren wrote:
> Wolfgang Denk wrote:
> > Dear Thomas,
> >
> > in message 
<D9F0B2AD4531B0449D51C1F09199D484050E72@mail.kom-saarbruecken.com> you wrote:
> >>Yes, I know that this has been discussed recently and the recommendation
> >>is to store the environment in flash, but:
> >
> > Indeed.
>
> [snip]
>
> >>- Are there conditions known to cause similar effects with flash chips
> >>as described for EEPROM devices? Could power loss or similar conditions
> >
> > No.
> >
> >>when writing environment sectors cause a flash device to destroy other
> >>sectors than the just written one?
> >
> > In theory yes. You could assume a  system  without  power  monitoring
> > where  the  power  is failing slowly so that at some point during the
> > brownout the CPU migth start executing  bogus  insructions,  or  that
> > some  bus  driver  corrupts  the  addresses  or data, or... In theory
> > anything can happen.
> >
> > Best regards,
> >
> > Wolfgang Denk
>
> Flash corruption is more than in theory: proper hardware design is to
> have a power fail warning sufficient to allow a flash write cycle to
> complete before power completely fails and your software should not
> write to the flash when the power fail warning is active.

I assume this is true for all flash CHIPS and not only higher level
assemblies like Compact Flash (that I read can be destroyed if written
to when power fails)

/RogerL