On Apr 21, 2009, at 11:04 PM, Bert Timmerman wrote: > Hi DJ, > > On Tue, 2009-04-21 at 23:35 -0400, DJ Delorie wrote: >> Update... >> >> I added serpentines to the short traces, and re-routed the long >> traces >> to go under the sdram chip instead of around it, and got the >> following... Only 381 mils difference between the shortest and >> longest. http://www.delorie.com/electronics/sdram/ >> > <snip> > > Your board looks nice, as always. > > I was told to avoid 90 degree angles in traces, it was something about > impedance or EMI, IIRC. > > You do not expect some EMI problems or high impedance from the 90 > degree > cornered angles ? >
Em fields are concentrated at sharp points, thats the main reason for not having 90 degree bends. In this case it is the sharp inside edge. I forget if the close parallel traces affect it but they might have an effect on impedance at much higher frequencies I wonder if by mentioning the serpentines would look cool as arcs, we would get a plugin that makes arc serpentines out of a line. ;-) >> And yes, I added a command to show the length of all nets. >> Report(AllNetLengths). I also used a script to remove the logic >> analyzer traces from the above report, and pull out the nets I >> wanted. >> >> > > Report(SelectedNetLengths) comes to mind (may be, or may be not > implemented yet). > > Kind regrds, > > Bert Timmerman. > > > > _______________________________________________ > geda-user mailing list > [email protected] > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
