On 11/14/2012 03:19 AM, Rick Walker wrote:
> Hi Dick,
>
>> In this thread, mostly we are trimming pad descriptions down with
>> this, since we do not have padstack support.
> For what it's worth, I just fabbed a kicad board that uses the bitfield
> mask to control the inner annular rings for a BGA footprint. I had to
> write a custom script to build my BGA footprints from a textual
> description file. By leaving the annular rings off of selected layers
> of the outer pads it made it possible to route out all the traces from
> the inner pads.
>
> I'd hate to see kicad lose it's current ability to fully control all the
> annular rings in a padstack independently through the textual
> description file.
I will attempt to answer your concern by assuming you were using a mixture of
through hole
pads interspersed in an among the the BGA SMD pads.
The strategy should still be possible with changes I committed last night.
(pad 2 thru_hole circle (at 1.27 0) (size 1.651 1.651) (drill 0.8128)
(layers *.Cu *.Mask F.SilkS)
)
becomes something like:
(pad 2 thru_hole circle (at 1.27 0) (size 1.651 1.651) (drill 0.8128)
(layers F.Cu Inner3.Cu *.Mask F.SilkS)
)
So it should work if you were to do it again today with a modified script,
except now you
can read the result.
>
> I don't mind if all the layers have english names, but it is nice to
> succinctly say: "put rings on layers 1,3 4 and 5 only" only", by using a
> hex number: 0x0000001D. Will the proposed changes still have some way
> to control all the annular ring layers independently in the
> textual description file?
See above.
>
> Some IC layout programs handle the layer names by internally referring
> to all layers by integers and having a process text file that gives the
> binding between user names and the integers. The process file also
> allows assigning things like layer colors, classes and characteristics.
> The user can either use the integer directly (or a bitmask), or can use
> the layer name defined in the process file as a synonym.
We talked about that, did not go that way after considering it. Footprint
files would be
burdened with layer maps in that approach. We have no such burden.
>
> One nice thing that could be put in such a file would be the gerber
> extensions for each layer. My current PCB fab house (4pcb.com) numbers
> the layers in opposite order to kicad,
I've expressed concerns about our sequence also, but at least now it will not
show up in
the data files in a hard coded way. So we could change sequence without
impacting the new
data files.
> and also prefers a different set
> of gerber extensions than kicad's default. I currently run a custom
> "tapeout" script on every design to rename all the layers to 4pcb.com's
> conventions.
Enjoy it.
>
> I really appreciate all the great work that has gone into kicad. It is
> one of the shining stars in the open source world.
>
> kind regards,
> --
> Rick Walker
>
>
>
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