design rules for classic computer PCB projects

---------------------------------------- Hi Cross talk through traces and ground bounce are to be avoided. Learning which crosstalks are most damaging is important. Two data bus signals that switch at the same time surprisingly don't need as much sheilding as a data bus signal and a write strobe signal. These signals switch at diffent times. The write signal switches when it is often critical that the data bus signal be stable. There are problems with a lot of signals switching at the same time but this is more related to speeding up or slowing the propagation of the signals. Use care when looking at ground and power traces. This is especially difficult for two layer boards. Coupling capacitors at the ends of power traces are not usually as good as those place at the centers of traces. Having alternate coupling across and then between power strips is a good idea. Try to keep power as clean as possible around chip that hold state ( flops and latches ). Keep runs of clock signals as short as possible. Avoid mixing clocks and data signal in the same chips. I know it is tempting to use every bit of your 7404 but the chips don't cost that much. Dwight _________________________________________________________________ Bing brings you maps, menus, and reviews organized in one place. http://www.bing.com/search?q=restaurants&form=MFESRP&publ=WLHMTAG&a…