lkml.org 
[lkml]   [2001]   [Jan]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [preview] Latest AMD & VIA IDE drivers with UDMA100 support
On Sun, 21 Jan 2001, Vojtech Pavlik wrote:

> On Sun, Jan 21, 2001 at 01:42:41PM +0100, Mike Galbraith wrote:
> > On Sun, 21 Jan 2001, Vojtech Pavlik wrote:
> >
> > > On Sat, Jan 20, 2001 at 02:57:07PM -0800, Andre Hedrick wrote:
> > >
> > > > chipset ---\
> > > > |
> > > > \---------IDC-header
> > > >
> > > > chipset ---+
> > > > |
> > > > +----------IDC-header
> > > >
> > > > These are nearly the same but the corners cause bounce and iCRC's
> >
> > I don't see how anyone can influence risetime falltime or impedance
> > matching [1] issues via software timing changes.
> >
> > (the top drawing is what you see on a poorly designed board.. long
> > rise/fall times often cause worse problems than [slight] ringing)
> >
> > > Well, there are other ways the motherboard maker can screw up the
> > > traces, and often this happens:
> > >
> > > chipset --------\
> > > |
> > > chipset ------\ |
> > > | \------ header
> > > \-------- header
> > >
> >
> > Can you compensate for these things (to any degree?) in software?
>
> Not really. Slowing the data rate down is in my opinion the only way to
> compensate for this. Btw, the chipset only controls the write data rate
> with UDMA. The read rate is controlled by the drive.
>
> > 1. Only a software guy would call it 'bounce'.. sounds funny ;-)

Er...I help design some of the hardware and the rules, so I do more than
just software. So does 'echo' or 'reflections'sound better than 'bounce'?

Cheers,

Andre Hedrick
Linux ATA Development

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:13    [from the cache]
©2003-2011 Jasper Spaans