[sdiy] PCB layout advice

[David G Dixon]

> Anything else I should add to the list?

Avoid long traces, and don't run traces carrying square waves in parallel
with anything that's high-impedance, or the square waves will jump over.

I like to run the power rails under the chips in two straight lines, and put
everything else beyond the chips.

I also like to run unavoidably long traces parallel to the chip axis, and
lay resistors and diodes and such perpendicular to these traces, straddling
them, as it were.

In my experience, if you keep your traces fairly broad (especially ground
traces) and work on a strict grid, you won't run into too much trouble.