feustel@netcom.UUCP (David Feustel) (01/05/91)
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. -- David Feustel, 1930 Curdes Ave, Fort Wayne, IN 46805, (219) 482-9631 EMAIL: netcom.uucp
ayman@zip.eecs.umich.edu (Ayman Kayssi) (01/05/91)
In article <20030@netcom.UUCP> 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 January 1991 issue of Modern Electronics has some kind of a comparison article among various cad packages and their uses. The focus is on schematic capture but they also discuss layout. <Ayman> -- [ Ayman Issam Kayssi | Email: ] [ Advanced Computer Architecture Lab. | ayman@caen.engin.umich.edu ] [ EECS Dept., Univ. of Michigan, Ann Arbor | ayman@eecs.umich.edu ]
jgd@Dixie.Com (John G. DeArmond) (01/05/91)
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) Marietta, Ga | "To be engaged in opposing wrong offers but {emory,uunet}!rsiatl!jgd | a slender guarantee of being right."
gkishida@ (Gregg Kishida) (01/06/91)
In article <5646@rsiatl.Dixie.Com> jgd@Dixie.Com (John G. DeArmond) writes: >>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. >>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. I definitely second this. Most PCB houses want Gerber files so they can produce their own photoplots. If you haven't dealt with a board maker, talk to one of their engineers and ask him what they want and what they can do (ie, # of layers, minimum track thicknesses, minimum spacing between adjacent tracks and pads, etc). Also check what their minimum charge per board run is. My company uses a PCB house which advertises as a quick turn, low volume shop, but they have a minimum charge of $2K per board run (I'll have a couple year's supply of our preamp boards - 2" square, 2 layers). Most houses charge by the number of through holes as well as by size, and most like an even number of layers. For complex designs, sometimes it may be cheaper to add an extra layer rather than a group of vias. >OrCad is kinda the industry leader and rightfully so. I used version 1.20 for a while. Gave up quickly. The reason was it should have been labeled as a beta version, rather than a production version. There were still many bugs in the program (like not being able to plot the board until I pulled up and replaced about 20 nets and not being able to create a power or ground plane - this from a program that is advertised as being able to autoroute up to 16 layers ?!). Don't get me wrong, I am not anti-Orcad, I haven't tried PCB-II, and I really like their schematic capture program, but watch out when a company puts out a brand new product. >Tango is also pretty good. I'm currently using Tango-PCB-II. My company just updated from an earlier version of the software, and it is almost completely different (this, actually, is good. The standard nickname for the earlier version was Tangle!) They currently have about 4 versions of their PCB package out: PCB-II, PCB-II plus, and two different autorouters. > >John > ------------------------------------------------------------ | | | | | | | Don't mind me, my job | | | | _ /| | is driving me crazy!! | | | | \'o.O' | | |____ | | =(___)= ----------------------------- \ | | U | | \ | | ACK! | Gregg Kishida | | | | gkishida@envy.eng.uci.edu | F.B.H.N.G. | | | | | ------------------------------------------------------------
tindle@ms.uky.edu (Ken Tindle) (01/07/91)
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. Take a look at DC-CAD (Design Computation) in NJ. OrCad is excellent if you have the bucks. Wintek is pretty bad. Try Express Circuits 1-800-426-5396 for a board shop- quality is top drawer, and their prices are good, too. They always beat R&D Circuits and Avanti every time I get a quote. I am not affiliated with any of these folks, though I use Express and DC-CAD myself. --------------------------\ /----------------------------------------------- INTERNET:tindle@ms.uky.edu | "Could you please continue the petty bickering? BITNET: tindle@ukma.bitnet | I find it most intriguing." --- Data, Ken Tindle - Lexington, KY | Star Trek, The Next Generation, "Haven" --------------------------/ \-----------------------------------------------