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Electronic Supplies, Microcontroller choice question.

Discussion in 'Electronic Design' started by [email protected], Dec 7, 2005.

  1. Guest

    I'm an amateur and I'd want to start by creating my own PCB development
    board, not actually go out and buy one but make one, design in FreePCB
    and then ship it off for fabrication. I've decided that the best way to
    go is to start on a breadboard and then design the PCB after manual
    verification, at least go as far as I can go.

    First what type of microcontroller should I use? I want something
    that's well supported, stable and is capable of running uCLinux (not
    absolutely required but would be nice). I've been looking into Texas
    Instruments, Freescale, and Microchip products. Most importantly is the
    compiler availablity. There needs to be a free compiler, I'm already
    spending enough money on parts, to go along with the chip. I have
    experience using 6812 processors but I'd prefer to move on beyond that.
    Other than that the microcontroller just needs to be flexible if it has
    some extra bells and whistles that's perfectly fine, I'm not trying to
    build an ultra low power device, at least not yet.

    One major thing I'm confused about is all these packaging types like
    SOIC and so on, I understand PDIP and that's pretty much it. And how
    would I get them on the breadboard?

    I probably need a new soldering iron, preferably a fine tip one which
    ones are good? Not sure too much about branding in the electronics
    field.

    Lastly, what's a list of some websites to get electronic supplies?
     
  2. young

    young Guest

    If you are just starting out using microcontrollers, Pic micro and
    basic stamps are good ones to start with. There are many websites and
    magazines that provide help for the chips. Eval board are nice to
    have, for learning. You can get the evals with breadboard attached to
    test your circuits.

    SOIC is a packaging for surface mount.

    Metcal has some good soldering irons but are expensive. To start, get
    a reasonably priced iron from radio shack and try it out.

    For part, visit www.digikey.com

    Have fun
     
  3. Guest

  4. Tim Wescott

    Tim Wescott Guest

    If you're really in the dark this may be the way to go, but with all the
    teeny packages these days the world is moving in the direction of
    designing PCBs for 1st-article testing. Even a PCB with a 144-pin chip
    turned over on its back and soldered in with 144 little green wires is
    better than a breadboard.

    I haven't used FreePCB; none the less I would recommend Eagle, if you
    can fit your board into the free version. It _has_ a free version, it
    has a stepped pricing scheme as you need more layers and size, and it
    has gotten good reviews here. I haven't actually shipped gerber files
    off and gotten boards back, but I have generated good looking gerbers
    with it.
    I think once you've done your research you'll know more than most of us.
    Check the resource requirements for uCLinux -- you'll have to bypass
    quite a few useful smaller (and easier to use) parts because of that
    requirement. I suspect that uCLinux will have a big enough RAM
    footprint that you'll need off-chip RAM and possibly off-chip flash as
    well, which means a lot more board work. Along with compiler
    availability I'd suggest that you consider the following:

    * Make sure you get the peripherals you want. You'll want at least one
    asynchronous serial port for debugging, and possibly one for whatever
    apps you want to run. Synchronous serial is good for connecting ADCs,
    DACs (and UARTs); if you just run it to a connector run a bunch of
    general-purpose I/O to the same connector.

    * If you make expansion connectors give them plenty of grounds.
    Alternating signal with ground would not be too much overkill.

    * I _always_ put at least one indicator LED to an I/O pin. Put
    something in the code that depends on the correct operation of your OS
    to make the LED blink. If it stops blinking you know that something is
    seriously wrong. Using this as a fault indicator is good in a "real"
    system, and getting it going is a good first exercise when you're
    bringing a board up for the first time (and it's incredible how cheered
    a manager can be when they see a board blinking away like the computer
    in "Desk Set").
    All the manufacturers make sure that you get mechanical drawings of
    their chips to see the packaging, and some have recommended board layouts.

    There are breadboard adapters out there.
    Metcal has been mentioned. It will get you there in style for a very
    high price. If I had a production lab I'd stock it with Metcal tools.
    I use a Weller temperature-controlled iron (WTCPT) that suits me just fine.

    It's kind of a Ford vs. BMW argument.

    _Don't_ try to do this with some cheapo thing from Rat-Shack. Even a
    good Weller that doesn't have temperature control will be difficult to
    use with tiny surface-mount components.
    In the US:

    New parts:

    www.digi-key.com
    www.mouser.com
    www.newark.com

    Surplus:

    www.allelectronics.com
    www.mpja.com
     
  5. Guest


    You should probably select your family of processor first, purchase an
    existing development board and make sure you can do everything on it
    that you want, including ucLinux. The select your specific processor
    and make the exact PCB that you want.

    I'm not aware of any PIC products that run ucLinux
    Atmel has several board that run ucLinux.
    http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3043
     
  6. blackbird_b

    blackbird_b Guest

    I have also started with programming with microcontroller. i m
    basically interested with mine detector controlling robot.I have
    started with 8051 family micocontrollers.i will keep u update with my
    proress.
     
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