[U-Boot-Users] Flash environment vs EEPROM environment
roger.larsson at norran.net
Tue Feb 1 22:28:57 CET 2005
On Tuesday 01 February 2005 20.06, Jerry Van Baren wrote:
> Wolfgang Denk wrote:
> > Dear Thomas,
> > in message
<D9F0B2AD4531B0449D51C1F09199D484050E72 at 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.
> >>- 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)
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