[SI-LIST] Re: SDRAM data bus SI problem

Peter, since the problem does not appear when the controller is the driver, 
I believe that the controller source termination is adequate.  It sounds 
like you have high inductance in your Vtt or grounds near the SDRAM.

Steve
At 10:33 PM 10/27/2004 +0800, peter zhu wrote:
>Hi,all:
>
>I encountered SDR SDRAM data bus SI problem. From the simulation, I see a
>serious ring during rising edge when source is SDRAM and the destination is
>SDRAM controller(point to point).  The ring cause the data error in memroy
>R/W operation.
>When I change the destination to another SDRAM, rather than this SDRAM
>controller,  no any ring and the simulation result is very good. So I think,
>maybe the SDAM controller(Marvell GT64260B) is not specification compliant.
>Now how to eliminate this ring?  For impedance match, I add series
>resistor(10Ohm to 40Ohm), and the ring is still, with the resistor value
>increased, only wave amplitude reduced, and the ring remains almost same.
>What should I do for eliminating the ring?
>
>Thanks
>
>Peter
>
>------------------------------------------------------------------
>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:
>http://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:
>                 http://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
>


------------------------------------------------------------------
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:
http://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:     
                http://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: