eye mask- DDR2 address/command
HiI would like to know whether any standard eye mask available for DDR2-address/command signals or not. Please clarify me.-- Best Regards,Balamanikandan.K
kbmanick 7 years 5 months 14 days
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Answered byHermann.Ruckerbauer 7 years 5 months 14 days
Hello,generating a single official eye-mask for a DDR2 source Sync interfaceis difficult (impossible ?!?).There are many parameters that are need to fulfilled on a cycle by cyclebasis and with different timing references.I tried to explain this a bit in the DDR3 Setup_Hold tutorial (validfor DDR2 as well):http://www.eyeknowhow.de/index.php/downloads/5-movies.htmlI usually measure the open data window (ODW) from last AC crossing tofirst DC crossing and compare this to the required setup/hold times (soi do not draw the required eye Mask, but i measure what my system provides).Just one example why it is difficult to work with a simple eye mask:If you draw the "mask" according to setup and hold times then you get amask that is smaller than the allowed tDIPW (data input pulse width).If you have a simulator it most likely provides a method to do the checkon a cycle by cycle basis (what would be the correct way to do).For ADS this check is available too, but as mentioned above I do usethis ODW measurement based on own Code. HermannEKH - EyeKnowHowHermann Ruckerbauerwww.EyeKnowHow.deHermann.Ruckerbauer@xxxxxxxxxxxxxItzlinger Strasse 21a94469 DeggendorfTel.: +49 (0)991 / 29 69 29 05Mobile: +49 (0)176 / 787 787 77Fax: +49 (0)3212 / 121 9008schrieb Balamanikandan K:> Hi> I would like to know whether any standard eye mask available for DDR2> -address/command signals or not. Please clarify me.>>