Some questions regarding pcb design

Discussion in 'Electronics Resources' started by ke5nnt, Oct 21, 2009.

  1. ke5nnt

    Thread Starter Active Member

    Mar 1, 2009
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    I have been using eagle cad to draw wiring diagrams and have found it to be really useful for that purpose. I'm now interested in diving into pcb layout, but I seem to be having problems on a few points. As stated in the title, here are some questions:

    1. The board I want to design first, I'd like to be about 2 inches (about 51mm) by 11 inches (about 280mm). This is far outside the space limitations for the freeware eagle cad software, I would need to buy the full professional version to be within these size limitations, and to be honest, I don't have $500.00 to spend. Is there an alternative that I can get that doesn't put such tight restraints on size?

    2. Where can I find a decent library of surface mount parts? I'm particularly interested in a 24 pin surface mount PIC microcontroller.

    3. Can someone please tell me what the heck SPICE stands for? lol, I realize that's probably a stupid question but I see it a lot.

    That's all, thanks.

    Ryan
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    The non-profit/educational license is $125 and will handle 160 X 100 mm. Fore 280 mm you are stuck with the standard license, another program, or splitting the board image. The latter would be a pain. Also remember, none of the free licenses allow commercial use.

    Have you checked ic-package.lbr ? It is rare that I cannot find a package in Eagle. When I have faced that problem, they are easy to make. I suggest starting with a similar package and modifying it, rather than starting with a blank page. Although, once you get used to it, the latter isn't hard to do either. Getting your pads in the right place is the most difficult step. And for that, setting the grid correctly is the biggest help.

    Edit: Also try ref-packages.lbr It has a 24-pin cfp package and many other smd packages.

    SPICE is a circuit simulation program. See: http://acronyms.thefreedictionary.com/SPICE

    "Simulation Program with Integrated Circuit Emphasis"

    John
     
    Last edited: Oct 21, 2009
  3. Thav

    Member

    Oct 13, 2009
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  4. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    I use Sprint Layout. Not expensive and I really like the interface.
     
  5. ke5nnt

    Thread Starter Active Member

    Mar 1, 2009
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    Thanks guys for the responses. That will help get me going.
     
  6. ke5nnt

    Thread Starter Active Member

    Mar 1, 2009
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    Can i use a library from eagle for a different pcb design program if they both use library files that end in .lbr? My assumtion is no but maybe I'll get suprised.


    EDIT: Instead of posting another time I'll just edit this question...

    I'm going to admit that I'm totally mind-boggled. Trying to break into PCB design for a beginner is giving me a headache. I want to build a board for a project I'm working on currently that is too large for eagle cad (as expressed earlier in this thread) so I decided, based on things I've read, that I'd give freepcb a try. Its free, it can handle 60 inches by 60 inches, and 16 copper layers. The library it comes with is a bit dismal, but you can't win them all.
    So, I'm trying to find libraries for freepcb without much success. Google searches turn up little, but people keep saying try ORCAD, or ORCAD exchange yahoo group, which leads me to the question about whether or not I can use library files from other programs for freepcb.
    Then there's all this stuff about SPICE, and netlists, and captureCIS, etc. I have no idea what any of that is, except for SPICE which someone described to me before.

    All I want is a free program to mess with so I can learn the routine to build my little board with a library that has the parts I want to use in it so I can give a go to making a PCB myself. In other words, define a board size, insert parts, draw traces, transfer toner, dip copper in poison liquid, solder, be happy...

    When I get used to using PCB design software and become a bit more familiar with it, then I'll move on to something I have to pay for. Can I do that with freePCB? do I need all these fancy tools?

    Sorry to rant but all these conflicting suggestions and unfamiliar tools are melting my brain.
     
    Last edited: Oct 25, 2009
  7. Thav

    Member

    Oct 13, 2009
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    I find that interoperability in electronics CAD is dismal at best. I would be surprised if you could find another program's library that worked. I've found even with plain schematic entry I've had to draw my own symbols and associate the packages, and I haven't gotten to the layout yet where I expect I'll have to draw some footprints as well.

    Sorry this post wasn't all that helpful, but I just wanted to let you know I feel your pain. Most large companies that use these commercial software suites usually have a component engineer that makes these libraries for them to their standards, so I don't think footprint libraries are that heavily utilized outside of hobbyist and small business.

    It has occurred to me that maybe if you have a PCB fab in mind they might have compatible footprint files for you. Maybe not for FreePCB, but hopefully for another free package. Worth a shot anyway.
     
  8. Thav

    Member

    Oct 13, 2009
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  9. AlexR

    Well-Known Member

    Jan 16, 2008
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    FreePCB is quite a nice program but to get the most out of it you must team it up with a circuit capture/drawing program (TinyCAD works fine and is free) to draw your circuit and create a netlist that can be imported into FreePCB, and a Gerber viewer to print out your final design (ViewMate have a free version that works well).

    FreePCB comes with a fairly extensive library but if the footprint you need isn't in there you can roll your own using the inbuilt footprint editor. Most data sheets have suggested footprint dimensions or you can download a free footprint calculator from http://www.pcbmatrix.com/. It also comes with lots of predefined footprints.
     
  10. ke5nnt

    Thread Starter Active Member

    Mar 1, 2009
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    Where can I find information on what a "netlist" is?

    Also, just to be sure I'm not slacking off I will again express my appreciation for all the help and advice I receive from this forum and its members.
     
  11. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The link is not terribly informative - http://en.wikipedia.org/wiki/Netlist

    Very basically, it is a file generated by your CAD application that forms a list of all the connections on the PCB.
     
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