[U-Boot] [resent] New chapter in i.MX51 datasheet an issue?

David Jander
2012-05-09T09:31:36Z

On Tue, 8 May 2012 14:51:52 +0200
Marek Vasut <marex@denx.de> wrote:

> Dear David Jander,
>
> > On Tue, 08 May 2012 10:46:10 +0200
> >
> > Stefano Babic <sbabic@denx.de> wrote:
> > > On 07/05/2012 09:11, David Jander wrote:
> > > > Dear Stefano,
> > >
> > > Hi David,
> > >
> > > > Yes, but is none of those boards using 3.15 or 3.3V? If they are, those
> > > > bits must be cleared!
> > >
> > > This is a good question - also because SD was tested and it is working
> > > on these cards. I am asking to myself how it can work if voltage is
> > > wrong.
> >
> > That is the whole point: You probably won't notice anything with the wrong
> > settings.... besides slightly lower drive-strength on the pin. Things
> > should just work with either setting. The problem is that now Freescale is
> > telling us that using the incorrect settings can cause "permanent damage"
> > to the chip!!! No idea what sort of damage nor whether it occurs
> > frequently.....
>
> I think it might have something to do with ESD. It's probably unlikely to happen
> anyway.

Why do you think that?
ESD protection is not something that could possibly have something to do with
a running board and wrong PAD configuration bit settings. Or do you mean that
IO-pad ESD protection is the thing that gets destroyed by wrong settings?

AFAICS, this bit probably enables and disables a different set of output
transistors on the pad.

Whether damage is likely to happen or not, is not clear to me yet. I am waiting
on a reply from Freescale about this issue right now. I will post any important
findings here as soon as I know more.

Best regards,

--
David Jander
Protonic Holland.