Re: [ECOS] NAND Flash support in eCos?

[Gary Thomas <gary at mlbassoc dot com>]

Please keep your replies on the list so that all may benefit.

Jim Seymour wrote:
> Gary Thomas wrote:
> > Jim Seymour wrote:
> > > I found a few discussions back in 2004 regarding eCos support for 
> > > NAND Flash, but can't find anything more recent.
> > >
> > > Has anybody implemented a flash driver for any NAND Flash chips? 
> > > (Specifically, the Samsung K9F1208U0B)  Our platform will be an Atmel 
> > > ARM9 (AT91SAM9260), if that matters.
> > >
> > > Related to this: Does anybody know of any easy-to-use error detection 
> > > and correction code?  I don't think I'll need a full file system, but 
> > > I'll need to at least have a simple lookup table in order to map 
> > > around bad blocks.
> >
> > NAND FLASH (RedBoot only, minimal drivers) is supported on the TAMS MOAB
> > using Toshiba chips.  Just look in the repository...
>
> Thank you.  This looks like a real good starting point for me.
>
> I'm curious, though.  The Toshiba drivers seem to assume the flash is in 
> code space - although NAND flash (as I understand it) cannot be used to 
> directly execute code.  Is this a legacy from the NOR flash driver it 
> was based on?  Or is there some eCos weirdness that I need to be aware of?

NAND FLASH is treated differently - it cannot be accessed
directly and the 'flash_read_buf()' function is used to stage
a portion of the FLASH into RAM.  The extant drivers do
not attempt to remap any bad sectors - simple bit error
discovery/repair using ECC only.

--
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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