Hi, Edi: On DDR layout, you can routing DQS/DQ(DM)/Clock with same lengrh. =20 On DDR2 layout, you can routing DQS and Clock with same length. But data and data mask must be shorter than DQS =20 B.R. Alex Li -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Fraiman, Edi Sent: Tuesday, September 26, 2006 9:50 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] DDR interface Hi all, I have question about DDR interface layout. I understand that during PCB layout the DQS (data strobe) should be routed with same length as DQ (data), DQM signals and Address bus and control signals (RAS,CAS, CKE,WE,CS) should be aligned to clock. But I do not understand what relationship (what the maximum difference in length) between DQS and CLOCK. Could you please advise? =3D20 Best regards, Edi Fraiman =3D20 =3D20 =3D20 - - - - - Appended by Scientific Atlanta, a Cisco company - - - - -=3D20 This e-mail and any attachments may contain information which is confidenti=3D al, proprietary, privileged or otherwise protected by law. The information =3D is solely intended for the named addressee (or a person responsible for del=3D ivering it to the addressee). If you are not the intended recipient of this=3D message, you are not authorized to read, print, retain, copy or disseminat=3D e this message or any part of it. If you have received this e-mail in error=3D , please notify the sender immediately by return e-mail and delete it from =3D your computer. ------------------------------------------------------------------ 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: =20 //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 =20 ------------------------------------------------------------------ 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