word line disturbance

[Charles Manning]

On Wednesday 15 October 2003 20:20, David Müller (ELSOFT AG) wrote:
> Hello
>
> Magnus Mårtensson wrote:
> > Hi.
> > I had a discussion with flash manufacturer Atmel last week regarding a
> > phenomenon that we had seen. The phenomenon was called "word line
> > disturbance" and it could occur if you tried to program only ones to a
> > location that already contained ones. The result could be that some bit
> > on another address got tainted. Ex writing 0xffff to address A could
> > result in the content on address B changing from 0xffff to 0xfffe.
>
> Does anybody know more about the technical background of this "it's not
> a bug, it's a feature" problem? Or is it just a manager driven decision
> to save some money at the wrong place?
>

This is likely to be the result of a compromise to simplify the flash 
internals to save cost. Some of these compromises are acceptable for certain 
usage scenarios, but not others. Atmel do this sort of thing a lot.

Atmel design their DataFlash range of parts for data use and their other 
parts for code storage. If the problem showed up in their Dataflash parts I'd 
consider it a true bug.

-- Charles