NAND flash in embedded designs?

Is anyone out there using NAND flash in an embedded design ?
If so, have you found it to be reliable ?

My application would primarily read form flash upon powerup and run out of 
ram.

No more than 5-10 flash updates (write), in a 10 year life cycle.

I'm aware of the fact that NAND is also prone to single-bit errors, which 
requires rigorous algorithms for error detection and correction.
What I'm also concerned with, is the possiblility of "bit flipping".

Does anyone haveexperience using NAND flash that they could share?

Regards,

/// -Joe 

Joe wrote:
> Is anyone out there using NAND flash in an embedded design ?
> If so, have you found it to be reliable ?

I've used NAND (8MByte) in a somewhat more demanding application, but
it hasn't been out there for 10 years yet. Similar to your intended
application, I had a small-n-cheap bootloader OTP EPROM that loads the
main firmware into RAM off the NAND flash. The difference in my case is
that the remainder of the NAND was used for storage of data files which
were rewritten quite frequently.

This was convenient because I put a SmartMedia slot on my device, and
developed the initial firmware using removable media. When it went
golden, I just took off the socket and added the chip.

That company is out of business, so now I'll never know if it would
last 10 years, but in product returns over the course of two years I
_never_ saw a single bad "decayed" bit generated after initial
programming.

yes. I use large block 256MB NAND flash in a super miniature design. I have 
found it to be extremely dependable. After bad block management. I do not do 
wear leveling because my application does not require it.


"Joe" <overstate99@yahoo.com> wrote in message 
news:LVNYg.65633$FU7.61344@fe01.news.easynews.com...
> Is anyone out there using NAND flash in an embedded design ?
> If so, have you found it to be reliable ?
>
> My application would primarily read form flash upon powerup and run out of 
> ram.
>
> No more than 5-10 flash updates (write), in a 10 year life cycle.
>
> I'm aware of the fact that NAND is also prone to single-bit errors, which 
> requires rigorous algorithms for error detection and correction.
> What I'm also concerned with, is the possiblility of "bit flipping".
>
> Does anyone haveexperience using NAND flash that they could share?
>
> Regards,
>
> /// -Joe
> 

"Joe" <overstate99@yahoo.com> wrote in message 
news:LVNYg.65633$FU7.61344@fe01.news.easynews.com...
> Is anyone out there using NAND flash in an embedded design ?
> If so, have you found it to be reliable ?
>
> My application would primarily read form flash upon powerup and run out of 
> ram.
>
> No more than 5-10 flash updates (write), in a 10 year life cycle.
>
> I'm aware of the fact that NAND is also prone to single-bit errors, which 
> requires rigorous algorithms for error detection and correction.
> What I'm also concerned with, is the possiblility of "bit flipping".
>
> Does anyone haveexperience using NAND flash that they could share?
>
> Regards,
>
> /// -Joe
>

Stick with SLC (single level cell) NAND rather than MLC (multi-level cell).
Multilevel Cell encodes more than one bit in a "cell" - meaning multiple 
threshold
voltages than simple on/off.   It therefore needs a better ECC than the 
simple
"parity of different selections of bits" of conventional ECC. (which is not
terribly rigorous, and corrects single bit errors).

In fact, I'm about to post a question on multi-bit ECC's, as market 
pressures may
not give me a choice not to support MLC devices...

Rufus

BTW there are NAND FLASH devices coming down the pipe which will contain a
control on-chip, so much of the mapping and error correction will be done 
for
you.  Look for iNand and OneNand (I think those are the names)

Thanks for the input all.
Spansion has a device that is NOR flash with a NAND interface.
The problem is that it appears geared towards consumer apps, and we'd have 
to buy an extremely large quantity.
The other links are helpful.

Thanks again.
// -Joe



"Joe" <overstate99@yahoo.com> wrote in message 
news:LVNYg.65633$FU7.61344@fe01.news.easynews.com...
> Is anyone out there using NAND flash in an embedded design ?
> If so, have you found it to be reliable ?
>
> My application would primarily read form flash upon powerup and run out of 
> ram.
>
> No more than 5-10 flash updates (write), in a 10 year life cycle.
>
> I'm aware of the fact that NAND is also prone to single-bit errors, which 
> requires rigorous algorithms for error detection and correction.
> What I'm also concerned with, is the possiblility of "bit flipping".
>
> Does anyone haveexperience using NAND flash that they could share?
>
> Regards,
>
> /// -Joe
>