> Hey Steven, that's a pretty interesting analysis. I just want to add > something from Dr. Howard Johnson's book on this stuff. His claim is > that you can treat a pcb trace as a lumped system if the trace is less > than 1/4 * 'length of the edge'. Well, at 170 ps/inch the length of the > edge is about 5.8" - that's exactly 1/2 your result.
If I remove the LA connector and shove the sdram closer to the fpga, I get a trace length range of 2027 mils (CLK) down to 281 mils (DQ7), a mis-match of 1.7 inches, or just under 1/3 of 5.8". I wonder if I could drive the shorter traces less than the longer ones, to match up the edges at the sdram? _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user