[ECOS] IO_Flash & DataFlash

Mike Jastrebtsoff jam2000@pisem.net
Tue Aug 31 12:44:00 GMT 2004

Hello, Savin.

I developed DataFlash driver some time ago,(but it wasn't finished)
and I had the same issue.

Simple solution is a ignoring of "unnecessary" bytes in DataFlash
page. DF Page size is 528 bytes and if we will align that to 512 bytes
we will losing 16 bytes per page only.

It can be used internally by DF driver for block regeneration(after
10.000 writes by Atmels's datasheet).

As for as I remember Atmels' proprietary filesystem - DFFS using this feature.

SZ> Hi,

SZ> I'am writing a DataFlash driver and I would like to use it also through
SZ> the io_flash API,
SZ> but it seems that the io_flash only supports 2^n block sizes (judging by
SZ> the calculation
SZ> and usage of block_mask). DataFlash memory array is divided into 3
SZ> levels - sectors,
SZ> blocks and pages of wich none has 2^n size. 

SZ> Supporting this in io_flash is probably just a matter of some ifdefs in
SZ> read/program/erase
SZ> functions - is this correct ? But does anything else (RedBoot, jffs2,
SZ> ...) also depend on
SZ> 2^n block sizes ?

SZ> thanx
SZ>         savin

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