The direction control rule of the trace: that is, the trace direction of the adjacent layers is an orthogonal structure. Avoid running different signal lines in the same direction on adjacent layers to reduce unnecessary interlayer interference; when it is difficult to avoid this situation due to board structure limitations (such as some backplanes), especially when the signal rate is high, It should be considered to isolate each wiring layer with a ground plane, and isolate each signal line with a ground signal line.
Open-loop inspection rules for wiring: Generally, wiring with one end floating (Dangling Line) is not allowed, mainly to avoid “antenna effect” and reduce unnecessary interference radiation and acceptance, otherwise it may bring unpredictable results.