At 10:47 AM 5/23/2002 +0100, Ivor Davies wrote:
>I have just joined this list and have my first query. We have a huge 
>number of PCB designs in Boardmaker (an old DOS package written by Tsien 
>of Cambridge, UK) and require to import them somehow into Protel.

BTW, there is a much newer version of Boardmaker. I do know that Boardmaker 
was interested in writing a Protel translator, but I think CAD companies 
generally avoid providing translators that translate *from* their own 
packages. It appears there may be legal issues with writing a proprietary 
file format; but there would be no such issue if the translator were a 
Protel server....

>It has been suggested that the Gerbers generated by Boardmaker can be 
>imported via Camtastic. How can this method recover the connectivity 
>between layers?

There is a lot of hand work involved, it is not just a matter of doing an 
import and then being done.

>  How can the plot of a pad on one layer relate to an identically 
> positioned plot of a pad on another layer? (or is Camtastic so fantastic 
> that is knows that such instances are vias?).

No, Protel is that fantastic, or, rather, a skilled designer driving 
Protel. Global edits make a lot of things possible.

Here is a general procedure:

Bring the gerber into CAMtastic; this step could be skipped if the gerber 
is compatible with Protel. CAMtastic output can be made compatible.

(There are some tools in CAMtastic that might assist in the process, I have 
not explored them.)

Bring in the gerber to Protel. You would ideally want to also bring in the 
drill data. I wrote a Tango utility that would import a drill file, looking 
for pads at the drill location. If it found a pad, it converted the pad 
(which starts out as a surface pad, being brought in from Gerber) into a 
through-pad with the appropriate hole. Since it is possible to import Tango 
to Protel, there might be a path to use here, but I'll assume that Tango is 
not available and one will manually deal with hole sizes.

Visually identify footprints and create these footprints in Protel. You can 
select the pads of a footprint and copy them into a library footprint. 
Create a footprint for all different components on the board. If the 
footprint contains through pads, assign the pads the appropriate hole 
(which will be known from a drill drawing or from a CAMtastic import of the 
drill file). The holes should also be given the correct pin numbers.

You'll need the Boardmaker net list to get those pin numbers, and also to 
check the finished list. It might be necessary to translate the list to 
Protel format, I have not researched this point.

Once you have all the footprints. Take, say, the top layer of the board and 
place the footprints over the existing free pads from the gerber import. 
Identify the via pad size and globally select all the via pads based on pad 
size (and possibly on drill size). Use the Convert tool to give all these 
pads the appropriate hole size and then to convert them to vias. Select all 
remaining free pads on the design. Unselect any free pads you want to keep, 
such as mounting holes. Delete all the free pads.

Keep your work at each stage, since you might easily make a mistake or run 
into some unanticipated condition and you might have to backtrack.

Note that the top layer not only has all the pads but it also has all track 
and vias for that layer. Delete all pads on other layers.

(I've described the import of a through-hole board; with SMT, one will 
merely need to place all bottom parts before deleting pads. I'd recommend 
building all the parts as top side parts; if there are bottom parts 
(footprints that are not used on the top of the PCB) I'd mirror the bottom 
layer and move it to a top layer (i.e., on a scratch PCB) before building 
the parts.)

The track routing should be correct already.

Complications: polygon fills if Boardmaker DOS had that; these could be 
left as drawn track, but if extensive changes are to be made it might be 
worth converting them to Protel polygons. split negative layers will 
require hand work to replace the split track with split plane segments.

When the board appears correct, load the net list and verify.

Fix any errors.

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