18 Mar
2016
18 Mar
'16
12:57 a.m.
On Mar 17, 2016, at 9:15 PM, Eric Smith <spacewar
at gmail.com> wrote:
On Thu, Mar 17, 2016 at 3:35 PM, Guy Sotomayor <ggs at shiresoft.com> wrote:
Thanks. I think I have it mostly figured out. ;-)
Still have to place all the caps. ;-) Then I can start to route everything.
TTFN - Guy
I?m planning on doing a 4 layer board so I can
avoid having routing issues due to 3 different
power supply voltages (yea, modern low voltage design meets 5v). I haven?t done a 4
layer
design before, so I?m in for a bit of learning (mainly on how to ?pour? the inner
layers).
In Eagle, you use the polygon tool, select the layer, and draw the
polygon for the entire board outline (or wherever you want the pour).
Then you use the "name" tool, select the polygon, and give it the name
of the net you want it connected to (e.g, GND). Once you've done
that, any time you do a ratsnest command, Eagle will recalculate the
polygon and connect all through-holes of that net to the polygon (with
thermals by default). It doesn't recalculate as you add or move
components, so it will look wrong until you give another ratsnest
command to recalculate it.
While working on the layout, I find the display gets annoying with the
polygons shown. Rather than hiding those layers, you can type "ripup
@;" to remove the polygon routing until the next ratsnest command. I
do that because I often have a few signals going through the layers
that are otherwise mostly power planes, and I don't want to hide the
entire layers because I want to see those signals.
Of course, this also works on the top and bottom side if you want
copper pour there.