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Re: NAND technical review

Jonathan Larmour wrote:
Jürgen Lambrecht wrote:
Rutger Hofman wrote:
Well, there is no way I can see into the future, but I definitely think
that the wire command model for NAND chips is going to stay -- it is in
ONFI, after all. Besides, all except the 1 or 2 most pioneering museum
NAND chips use it too. There are chips that use a different interface,
like SSD or MMC or OneNand, but then these chips come with on-chip bad
block management, wear leveling of some kind, and are completely
different in the way they must be handled. I'd say E's and R's
implementations are concerned only with 'raw' NAND chips.
Correct, only for raw NAND chips to be soldered on a board. The others
have an embedded controller and are already packaged.

I don't think E's implementation would have the same problem with OneNAND as R's (see below). Yes it has a sort of controller, but it's not as advanced as an MMC or SSD one - instead it's there as logic to manage exchanges between its SRAM and the NAND array.

One could say that makes it a more realistic emulation. But yes I can
see disadvantages with a somewhat rigid world view. Thinking out loud, I
wonder if Rutger's layer could work with something like Samsung OneNAND.
See my comment above. The datasheet on e.g. KFM{2,4}G16Q2A says:
"MuxOneNAND™‚ is a monolithic integrated circuit with a NAND Flash array
using a NOR Flash interface."
Indeed, a oneNAND is to be threated as a NOR flash, like a pseudoSRAM is
a DRAM with SRAM interface.
And SSD has a hard disk drive interface, just like MMC and SD card; they
mostly have a FAT file system on them but also UFS ...

FAOD, I don't believe that's true. You only get a view into a small window
of the NAND. That small window is memory mapped, but that's all. It's
certainly not controlled like a NOR flash. It's a NAND, but not one with
the wire command model that R's implementation assumes.
I'm sorry Jifl, I did not check oneNAND very well. I read a bit about it some time ago when I was looking for a bigger NOR flash for our ARM7 board.
--["No sense being pessimistic, it wouldn't work anyway"]-- Opinions==mine

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