🚀 go-pugleaf

feustel@netcom.UUCP (David Feustel) writes:

>I'm a rank novice getting ready to build a pcb board using a slightly
>modified schematic of a circuit in the public domain. I want to
>produce artwork that I can send to a PCB maker who will produce the
>pc board for me in sample quantities. Which of the above-mentioned
>(or unmentioned) software packages would be best for me and why?
>Thanks.

The first question to ask is which brands does your board shop support.
You do NOT want to send them artwork.  You want to send them the CAD file
and let them plot it on their Gerber photoplotter and create their own
drill tape.  That way you get high precision artwork, your holes are
guaranteed to register, the solder mask lines up AND as importantly, you
gain the benefit of the expertise of the board shop.  They generally know
a LOT more about setting up photoplots than does the average infrequent
user and can advise you as to marginal techniques BEFORE the artwork is
made.  

Now to your question.  I'm currently reviewing the low cost CAD packages
for an upcomming series of articles in "Midnight Engineering" magazine
so the topic is fresh :-)

OrCad is kinda the industry leader and rightfully so.  The software is 
of high quality, the user interface is nice, the support is excellent and
the library is very complete. If you are interested in OrCad, you should
buy now, as the next version is going up significantly in price and
they'll supply free upgrades to those who buy now.  Also, if you call
their local distributor in your area, they will supply you an evaluation
copy that consists of the fully functional package, only with a copy
protection dongle.  You can use it for a month or so and see how  you
like it. 

Tango is also pretty good.  I've not worked with it nearly as much yet, and
I don't have the latest copy to evaluate.  Nontheless, the people I know 
who use it seem to like it very well.  I've not seen it listed in board
shop ads as being as supported as OrCad but there are a few around.

Schema looks nice, though I've not gotten a functional version to review
yet.  My first attempt writing to them as an interested customer requesting
a copy to evaluate got me a non-functioning demo disk that tells me little.
I'll be trying again as a reviewer.

UltiBoard also looks good in the demos but like Schema, I've only gotten a
useless demo disk.

EE Designer and Wintek are both garbage.  Wintek is very simplistic, 
being quite similiar to a paint package and is copy protected (as of about
a year ago when I naively orderd a copy to evaluate.  Considering that
you can buy OrCad for about the same money, Wintek is not worth looking 
at.

EE Designer is probably the worst software I've ever tried to use regardless
of function.  I think that the old cardpunch Fortran programs I wrote in
college were easier to use.  The stuff's written in Microsoft Basic to
give you an indication of how bad it is.  Plus it's copy-protected with
a dongle and their policy is NOT to replace the dongle if it goes bad.
I used EE-II for the better part of a year because a client wanted me to
and I can honestly say that I can lay a board out faster with tape and
mylar than I can with this garbage.  I truely believe that the disks
are worth more blank than they are with this trash on them.

One nice for the price little package is SuperCad from PCBoards in Birmingham,
Al. (205) 933 1122  The schematic capture, board layout and autorouter
are $99 each and he offers a package for about $250.  I'd not recommend
this package for professionals but it's just fine for hobbyists.  If you
use this package, you will have to deal with the board shops with artwork
because none that I know of support it.  Nontheless, not a bad little 
package.


IF you look at a package I've not mentioned, here are some evaluation tips:

*	Does it auto-pan.  That is, when your cursor hits the edge of the 
	screen, does the screen pan to follow?  If you have to stop and
	manually pan, you lose a LOT of productivity.

*	Does the package use EMS memory and/or can drawings and layouts
	be broken across several files?  Very important.

*	How big is an object?  The better packages store graphic objects
	as tokens that point into libraries.  That way, large files take
	up a surprisingly small amount of RAM.

*	How easy is it to label nets and how easy is it to continue a net
	across drawings.  EE designer is probably the worst and is a 
	prototype of what to avoid.  To label a net, you must go back after
	the fact and edit the net name.  IF you want to continue a net from
	one schematic to another, you must start the name with an asterisk!
	This totally bastardizes the meaning of "*" which is usually 
	interpreted to mean "negative true".  What a piece of sh*t.

*	How well does the back-annotation work?  IF you make major changes
	to the circuit design during layout, how are the changes back-annotated 
	into the schematic.  The good packages place the new components at
	a reasonable location and ratsnest the connections.  The poor ones
	like EE-designer tend to drop anything more complicated than a gate
	swap inside the same package.

*	Is the package copy-protected?  Though copy protection is rightly hated
	in the general software market, it is especially hideous on a CAD package.
	Why?  Easy.  You'll probably want to install a second copy on an XT or
	equivalent to serve as a plotter driver.  Plotting, especially when
	you are doing a production-grade proof plot can take hours.  You
	hardly want to tie your main machine up all day driving a plotter.
	If there is copy protection, you have no choice.  Spoolers generally
	don't work because a moderately complex board may generate 10 mb of
	plot data.

*	For the reason above, will the package run on an XT?  At least the 
	plot routine should.

*	How easy is it to create a new library part?  Some packages such as
	EE designer make this an adventure.  Can you create a part on the
	fly while in the schematic or PCB editor and then backfit it to the
	appropriate library later?  If not, you'll lose a lot of time.

*	Can the package manage revisions?  None I've evaluated to date do a
	very good job, though OrCad tries.  The ideal system would be for
	each revision diff to be stored in a drawing database similiar to
	SCCS.  You should be able to call up old revisions at will.  It is 
	not uncommon to keep several revisions of a board around for different
	purposes.

*	Can you merge drawings to make a larger one?  If so, this will allow
	you to construct building blocks that you can paste into a layout
	or schematic.  For example, you might want to lay out an 8031, a 
	couple of ROM and a RAM chips and save it as a block.  Then in your 
	next  8031 project, you simply read in the block and customize from
	there.

This list is not complete but it'll get you started.

The board shop I like to work with the best is Colt Technologies in 
Lenexa Kansas (913) 888 1673.  They support all the major CAD packages,
do multilayer boards, can do MIL spec if necessary, can do true 24 hr
turnaround if you can pay about 2X and have a BBS that facilitates
getting the CAD file to them.  When I do a board, I modem the CAD file to
them, leave mail asking for a quote and generally get a call back  within
the hour.  Plus they have a couple of gals in the layout department that
are phenomenal.  I've had them call me with errors they've discovered
even after I've run all the design rule checks, bluelined the layout and
had a second party follow up  behind me. 

John

-- 
John De Armond, WD4OQC        | "Purveyors of speed to the Trade"  (tm)
Rapid Deployment System, Inc. |  Home of the Nidgets (tm)
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