On Friday 19 October 2007 07:25:19 am Michael Sokolov wrote: > I know there are a few old-timers on this list (by that I mean hardware > engineers of old school), and my question is directed to those. Would > anyone here happen to experience designing a system with the good old > Motorola MC68302?
Those were the days... :-) > I've been told that when a sufficiently fast-switching signal is driven > onto a sufficiently long net, one has to worry about this signal ringing > due to transmission line effects. The Motorola classics: AN1051: Transmission Line Effects in PCB Applications [.PDF 1.5M] AN1061: Reflecting on Transmission Line Effects [.PDF 58k] are worth a read. You can find them on my site at http://www.designer-iii.com/ do a search for "LVDS". > I hope someone can give me some insight, preferably backed by some > actual experience with M68K designs. Pay particular attention to the timing margin of the Write# line, been so long since I did 68K I don't recall what it was called, but I do remember the Write Pulse could be much shorter than you really wanted it to be when you looked at the setup&hold times of the devices on the bus. Take a look at the "DTACK Grounded" archives: http://www.amigau.com/68K/dg/dg.htm -- http://www.wearablesmartsensors.com/ http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user