curious questions
Markus Schiltknecht
markus at bluegap.ch
Wed May 21 05:52:14 EDT 2008
Hi,
thanks for your quick answer!
Jörn Engel wrote:
> You can erase no less than one erase-block. For NAND, you cannot easily
> write less than one page. Sometimes subpage writes work, sometimes they
> don't, they have strange limitations and are best ignored in the
> beginning.
So, with mtd, I can erase the erase-block spanning pages 0 to 63, and
then, write to page 0, wait for more data and only then write page 1, right?
>> Can I repeatedly write to a NAND flash page, to set its bits to 1
>> (without resetting any bit to 0) (or vice-versa for XOR)?
>
> Erase sets bits to 1, writes sets them to 0.
Ah, that applies to NAND as well as NOR, good.
> With old NOR flashes, you can repeatedly write the same area to flip
> single bits. Writes with all 1's are essentially noops, so to set a
> single bit write a word will all but one bit set to 1. With ECC you'd
> have to flip bits on the ECC backwards, which doesn't work. NAND has
> ECC, so ordinarily this trick won't work.
Yeah, ECC certainly wouldn't work for that. Good explanation, thanks.
Markus
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