[sdiy] RS274D Gerber File

[Merv Thomas]

Hi Ray,

I'll root through what I have when I get into work tomorrow and see if
there's anything else I can send you ... in the meantime, the 274X stuff you
have _is_ relevant as 274D is a subset.

Is the X stuff you have the Barco 'Gerber RS-274X Format User's Guide' ? If
so, then it's probably all you'll need - great bit of work that. Just ignore
all the X stuff and use the 274D stuff. As far as the D stuff goes, forget
the N codes and G codes, they are totally unnecessary. Also forget the I, J
stuff, it's a class 1 PITA and I've never seen it used in anything other
than programming manuals put out by plotter manufacturers to show they're
compliant with the standards. In general, data is usually in INCHES,
coordinates are ABSOLUTE rather than INCREMENTAL and are represented as 5
digits [2.3]. Zero suppression is optional but if you're going to do it
suppress the leading zeros rather than the trailing zeros. The only M code
you'll need is M02* ... stick it at the end of your file ... again, it's
unnecessary but what the hey, it's like a full stop at the end of a
sentence. The main workhorse of the 274D spec is the D code. Anything below
10 is a motion command ... D01: light move, D02: dark move, D03: flash.
Anything 10 and up is an aperture. Most commands are modal - once set they
do not need to be reoutput until they change. For instance, for an 8 pin DIP
pattern you could output something like this:

D24*X10000Y10000D03*    ``assuming 2.3, ABS coord format. Select aperture
24, move to X Y and 'flash'
D24*X10000Y09900D03*    ``etc
D24*X10000Y09800D03*
D24*X10000Y09700D03*
D24*X10300Y09700D03*
D24*X10300Y09800D03*
D24*X10300Y09900D03*
D24*X10300Y10000D03*
M02*    ``M02* = end of program

in the interests of economy you could reduce this to:

D24*X10000Y10000D03*    ``select aperture 24, move to X Y and 'flash'
Y9900D03*    `` just move in the Y and flash again
Y9800D03*    `` etc
Y9700D03*
X10300D03*    ``now move in the X and flash again
Y9800D03*    `` and back up the Y
Y9900D03*
Y10000D03*
M02*

Slipped in a bit of leading zero suppression there too, and as long as you
tell your board shop you've done that and tell him that D24 is [for
instance] an 80 thou solid circle ... no problem. There are arguments for
not stripping data down ... most of these reductions came about when modems
ran at 300 baud and there was a real need to keep the data small as
possible. Then along came high speed modems, compression programs and
suddenly it didn't seem quite so important, but old habits die hard.

Have you thought about providing CNC data for drilling ? The formats are
very similar to Gerber ... your board shop will love you if you can give him
that in a ready to go form.

So, as I said ... I'll have a look through my stuff at work tomorrow. In the
meantime, give me a shout if I can help in any way


Happy trails ...



Merv



.
----- Original Message -----
From: Ray Wilson <raywilson at comcast.net>
To: Merv Thomas <history at mezzie.demon.co.uk>; <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, December 11, 2003 6:15 AM
Subject: Re: [sdiy] RS274D Gerber File


> Hi Merv
>
> I would prefer to go with the rs274d due to the fact that it seems to be
> very well supported by board houses. I received a great PDF for the x
> version but I am still looking for the plainer and older rs274d. If you
know
> of a link to it I would appreciate a URL. Once I get this going I am only
> going to be interested in describing single sided "pretty doggone simple"
> boards so if you are aware of a subset that supports this "simpler" use of
> Gerber I would appreciate a steer in that direction as well.
>
> Thanks
>
>
> ----- Original Message -----
> From: "Merv Thomas" <history at mezzie.demon.co.uk>
> To: <synth-diy at dropmix.xs4all.nl>
> Sent: Wednesday, December 10, 2003 3:14 PM
> Subject: Re: [sdiy] RS274D Gerber File
>
>
> > Ray,
> >
> > Big differences between rs274x and rs274d mind ... choose the right one
or
> > you'll be writing code for months. Lots of wierd stuff in 274x like
> macros,
> > drawn 'apertures' as flashes, layers, merged pos and neg images etc.
> >
> > Bon chance, mon ami. If I can help, let me know ... in a previous
> > incarnation, I worked in the heady world of PCB design and manufacture
for
> > many years.
> >
> >
> >
> > Happy trails ...
> >
> >
> >
> > Merv
> >
> >
> > ----- Original Message -----
> > From: Magnus Danielson <cfmd at bredband.net>
> > To: <raywilson at comcast.net>
> > Cc: <mab at cruzio.com>; <synth-diy at dropmix.xs4all.nl>
> > Sent: Wednesday, December 10, 2003 9:16 PM
> > Subject: Re: [sdiy] RS274D Gerber File
> >
> >
> > > From: "Ray Wilson" <raywilson at comcast.net>
> > > Subject: Re: [sdiy] RS274D Gerber File
> > > Date: Tue, 9 Dec 2003 19:37:22 -0700
> > > Message-ID: <003e01c3bec6$8a46e590$6701a8c0 at rayw.webserver.net>
> > >
> > > > Thanks Mike but I need the whole enchilada because I want to
implement
> > it
> > > > into a program myself. I will check out the GNU stuff to see what I
> can
> > > > learn. Thanks for your help.
> > >
> > > You can learn alot, since Stefan (who I know) had to work hard in
order
> to
> > make
> > > it deal with all the kind of strange quirks there is in the real life
> > Gerber
> > > files. There are a few specs flying around.
> > >
> > > Barco/Gerber's Gerber RS-274X Format User's Guide:
> > > http://www.pcbtech.ru/pcb/dlz/rs274xc.pdf
> > >
> > > Quick-guide:
> > > http://www.etsind.com/dloads/MBarco/Softwa/274X.pdf
> > >
> > > Cheers,
> > > Magnus
> >
>