Hi,
I am usng KiCad BZR 6078. I am on linux Centos 7. My question concerns
Pad Stacks and the Push-Pull Auto router.
Background
I have a 2x23 IDC Dupont Pin header with 0.1 inch spacing, a Beagle Bone Black
header. This header has circular through hole pads of two rows and 23 columns.
I am trying to make a cape. I would like to be able to route to pins through
one row of the 2x23 pin header, instead of going the long way around the header.
I am using a two copper layer board.
What I decided to try and do was to have one of the rows with Pads on the
F.Cu (Front Copper) and B.Cu (Back Copper), and the other row with
just F.Cu (Front Copper). The idea being to get at one row I use F.Cu,
and to get at the other row I can use B.Cu and route underneath the
first row of F.Cu pads.
Issue / Problem
When I hit F11, and use the OpenGL push pull router, the router always
goes the long way round, even though there are no B.Cu pads to stop routing
directly. Here is a snipped from the BeagleBone Black kicad_module file.
If you observe pad C12, this has only Front Copper, but pad C13 has both
Front and Back Copper.
(module BeagleBoneBlack4Woofie (layer F.Cu) (tedit 55CBE1AF)
(tags “beaglebone black”)
(fp_text reference U? (at 0 1.778) (layer F.SilkS) hide
(effects (font (thickness 0.3048)))
)
(fp_text value “BEAGLEBONE BLACK” (at 0 -1.143) (layer F.SilkS) hide
(effects (font (thickness 0.3048)))
)
(fp_line (start 22.86 -6.35) (end 22.86 11.43) (layer F.SilkS) (width 0.15))
(fp_line (start 22.86 -6.35) (end 43.18 -6.35) (layer F.SilkS) (width 0.15))
(fp_line (start 43.18 -6.35) (end 43.18 11.43) (layer F.SilkS) (width 0.15))
(fp_line (start 43.18 11.43) (end 22.86 11.43) (layer F.SilkS) (width 0.15))
(pad M1 thru_hole circle (at -37.465 -20.955) (size 4.572 4.572) (drill 3.175) (layers *.Cu *.Mask F.SilkS))
(pad M2 thru_hole circle (at 28.575 -24.13) (size 4.572 4.572) (drill 3.175) (layers *.Cu *.Mask F.SilkS))
(pad M3 thru_hole circle (at 28.575 24.13) (size 4.572 4.572) (drill 3.175) (layers *.Cu *.Mask F.SilkS))
(pad M4 thru_hole circle (at -37.465 20.955) (size 4.572 4.572) (drill 3.175) (layers *.Cu *.Mask F.SilkS))
(pad C1 thru_hole rect (at 23.495 -25.4) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C2 thru_hole circle (at 23.495 -22.86) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C3 thru_hole circle (at 20.955 -25.4) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C4 thru_hole circle (at 20.955 -22.86) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C5 thru_hole circle (at 18.415 -25.4) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C6 thru_hole circle (at 18.415 -22.86) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C7 thru_hole circle (at 15.875 -25.4) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C8 thru_hole circle (at 15.875 -22.86) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C9 thru_hole circle (at 13.335 -25.4) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C10 thru_hole circle (at 13.335 -22.86) (size 1.8 1.8) (drill 1.1) (layers F.Cu F.SilkS F.Mask))
(pad C11 thru_hole circle (at 10.795 -25.4) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
(pad C12 thru_hole circle (at 10.795 -22.86) (size 1.8 1.8) (drill 1.1) (layers F.Cu F.SilkS F.Mask))
(pad C13 thru_hole circle (at 8.255 -25.4) (size 1.8 1.8) (drill 1.1) (layers *.Cu *.Mask F.SilkS))
Could there be a bug / feature in the push pull router that always sees all the Pads on a “thru_hole”
even though they are on one layer only? The router seems to refuse to route through on the Back Copper
even though there are no pads there in the way.
Is there something else I had to do to tell the auto router that it is OK because we are on the Back
Copper and it is OK to route underneath the Front Copper pads?
I looked at some posts regarding PadStacks, and noted that PadStacks are a sort of a newish concept
in KiCad.
Thank you for your kind help.
Warmest regards, Mike.
