[SI-LIST] Re: termination for routing 8 SDRAMs to single Processor
- From: "Dimiter Popoff" <dp@xxxxxxxxxxx>
- To: steve weir <weirsi@xxxxxxxxxx>, "Kenneth W. Egan" <kegan@xxxxxxxxxxxxx>, "" <aavinda12@xxxxxxxxx>, "" <si-list@xxxxxxxxxxxxx>
- Date: Thu, 11 Aug 2005 09:07:45 +0300
Like I mentioned, he controller was an 8240 (MPC8240 of Motorola, now
Freescale).
If keeping connections within about an inch or just somewhat more length
is luck, then I guess I have been lucky.
Dimiter
------------------------------------------------------
Dimiter Popoff Transgalactic Instruments
http://www.tgi-sci.com
------------------------------------------------------
-------Original Message-------
> From: steve weir <weirsi@xxxxxxxxxx>
> Subject: Re: [SI-LIST] Re: termination for routing 8 SDRAMs to single
> Processor
> Sent: Aug 11 '05 09:03
>
> Dimiter, you may have lucked out on that one. Repeated, excess overshoot
> is well demonstrated to shorten the life of components, especially newer
> low voltage devices. What was the controller?
>
> Steve.
> At 08:55 AM 8/11/2005 +0300, Dimiter Popoff wrote:
> >Is about 4 years practically continuous operation good enough?
> >The design has demonstrated it.
> >
> >Dimiter
> >
> >------------------------------------------------------
> >Dimiter Popoff Transgalactic Instruments
> >
> >http://www.tgi-sci.com
> >------------------------------------------------------
> >
> >
> >
> >
> >-------Original Message-------
> > > From: Kenneth W. Egan <kegan@xxxxxxxxxxxxx>
> > > Subject: RE: [SI-LIST] Re: termination for routing 8 SDRAMs to single
> > Processor
> > > Sent: Aug 11 '05 05:21
> > >
> > > The question might not be one of stability, but one of reliability in
> the
> > > long term. Sure, you'll probably meet setup and hold to/from the SDRAM.
> > > However, SDRAM typically has some pretty hot drivers (that I've seen,
> > > simulated and measured in circuit ) and the real issue is over stressing
> > > The input protection on the receiver, i.e. overshoot issues.
> > >
> > > Failure modes in this case may not occur until much later in time.
> > >
> > > KWE
> > >
> > >
> > > -----Original Message-----
> > > From: si-list-bounce@xxxxxxxxxxxxx
> > [mailto:si-list-bounce@xxxxxxxxxxxxx] On
> > > Behalf Of Dimiter Popoff
> > > Sent: Wednesday, August 10, 2005 8:00 PM
> > > To: aavinda12@xxxxxxxxx; si-list@xxxxxxxxxxxxx
> > > Subject: [SI-LIST] Re: termination for routing 8 SDRAMs to single
> > Processor
> > >
> > > I have rooted 8 x8 SDRAMs to an 8240 without any terminations and it
> > worked
> > > remarkably stable. However, I had 64 data bits rather than 32.
> > > I had put 4 SDRAM chips on top and 4 on the bottom of the board,
> > practically
> > > next to the CPU, no connectors between.
> > >
> > > Dimiter
> > >
> > > ------------------------------------------------------
> > > Dimiter Popoff Transgalactic Instruments
> > >
> > > http://www.tgi-sci.com
> > > ------------------------------------------------------
> > >
> > >
> > >
> > >
> > > -------Original Message-------
> > > > From: Aravnda G <aavinda12@xxxxxxxxx>
> > > > Subject: [SI-LIST] termination for routing 8 SDRAMs to single
> > > > Processor
> > > > Sent: Aug 11 '05 03:29
> > > >
> > > > Hi All,
> > > > I am working with a micro-processor conneted to 8 SDRAM with 12
> address
> > > lines to all SDRAMs and 32 data lines each to two sets of four SDRAMs.
> > I was
> > > wondering if anyone has managed to route this sort of topology without
> > using
> > > terminations. If so please send information on topology used. The IO are
> > > lvttl compatible at 3.3V. Any input on routing possibilities is welcome.
> > > >
> > > > Thanks & Regards,
> > > > Alex.
> > > >
> > > > ---------------------------------
> > > > Yahoo! Mail
> > > > Stay connected, organized, and protected. Take the tour
> > > >
> > > > ------------------------------------------------------------------
> > > > To unsubscribe from si-list:
> > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> > > >
> > > > or to administer your membership from a web page, go to:
> > > > //www.freelists.org/webpage/si-list
> > > >
> > > > For help:
> > > > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> > > >
> > > > List FAQ wiki page is located at:
> > > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> > > >
> > > > List technical documents are available at:
> > > > http://www.si-list.org
> > > >
> > > > List archives are viewable at:
> > > > //www.freelists.org/archives/si-list
> > > > or at our remote archives:
> > > > http://groups.yahoo.com/group/si-list/messages
> > > > Old (prior to June 6, 2001) list archives are viewable at:
> > > > http://www.qsl.net/wb6tpu
> > > >
> > > >
> > > >
> > > -------Original Message-------
> > > ------------------------------------------------------------------
> > > To unsubscribe from si-list:
> > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> > >
> > > or to administer your membership from a web page, go to:
> > > //www.freelists.org/webpage/si-list
> > >
> > > For help:
> > > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> > >
> > > List FAQ wiki page is located at:
> > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> > >
> > > List technical documents are available at:
> > > http://www.si-list.org
> > >
> > > List archives are viewable at:
> > > //www.freelists.org/archives/si-list
> > > or at our remote archives:
> > > http://groups.yahoo.com/group/si-list/messages
> > > Old (prior to June 6, 2001) list archives are viewable at:
> > > http://www.qsl.net/wb6tpu
> > >
> > >
> > >
> > >
> > >
> >-------Original Message-------
> >------------------------------------------------------------------
> >To unsubscribe from si-list:
> >si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> >
> >or to administer your membership from a web page, go to:
> >//www.freelists.org/webpage/si-list
> >
> >For help:
> >si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> >
> >List FAQ wiki page is located at:
> > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> >
> >List technical documents are available at:
> > http://www.si-list.org
> >
> >List archives are viewable at:
> > //www.freelists.org/archives/si-list
> >or at our remote archives:
> > http://groups.yahoo.com/group/si-list/messages
> >Old (prior to June 6, 2001) list archives are viewable at:
> > http://www.qsl.net/wb6tpu
> >
>
>
>
-------Original Message-------
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
