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Connection between Sharc 21469 and DDR2

Question asked by daniloz on Apr 1, 2010
Latest reply on Apr 17, 2010 by AlClark

Hi,

 

I am starting a new design with the new Sharc 21469 and I was looking for some information concerning the connection of the DSP with the DDR2 memory. I am mostly interested in PCB layout guidelines, including the using of serial resistors.

 

I see in the Evaluation Board (21469-EZBRD) that a 33R series resistor is used between the DSP and the DDR2 memory. However, from was I’ve read, if the track is small enough (which is the case), no resistor should be necessary. Moreover, I also see that almost all digital lines on the EV-board have these series resistors (DPI, DAI etc...), so I am wondering if they are there more for protection and are not really required I a final design.

 

Anyway, I remember that for the 3rd generation of Sharc DSPs, Analog Devices had an application note on connecting the 21369 with the SDRAM which was really helpful. Is there something similar for the 21469 and DDR2 memory? I couldn’t find anything on the ADI website, but maybe you have some preliminary App Note ready. :-)

 

Thank you very much in advance,

Danilo

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