[SI-LIST] Re: SDRAM data bus SI problem
- From: steve weir <weirsp@xxxxxxxxxx>
- To: peter.zhu@xxxxxxxxxx, <si-list@xxxxxxxxxxxxx>
- Date: Wed, 27 Oct 2004 09:00:08 -0700
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
>
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