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Newbie - hardware

Discussion in '8bit Microcontrollers' started by Thomas Ruschival, Jul 25, 2003.

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  1. Hi,
    I am an untainted newbie in the microcontroller world, altough a Programmer
    and a student of electronic engineering. First I go to state that my target
    isn't to have a solution as soon as possible but to learn alot about the
    subject. So I want to layout and build my own board and not by a development
    board. The Problem is there are thousands of Microcontrollers that do almost
    the same - I need a quite univeral one, so I can use it for different
    projects.
    Requirements:
    1.) it must be able to communicate with a RS232 interface
    2.) I'd like to program it with standard C on my computer, thus i must be able
    to load programs through a RS232/USB interface. I don't want to buy
    programming hardware.
    3.) It should be powerful enough to control a 4 line LCD. and have some input
    pins for buttons.
    4.) onchip RAM and FLASH for the program would be great.

    Can you recommend me a chip or books where to start studying this subject. BTW
    can you recommend me a distributor for chips and LCDs in Germany.

    Thanks
    Thomas
     
  2. happyhobit

    happyhobit Guest

    Hi Thomas,

    Well I like the AVR 8-Bit RISC microcontrollers. Free assemblers,
    C-compilers, simulators and IDE's.

    I program through a parallel interface (4 resisters and a ribbon cable) but
    I've seen several schematics for a serial interface. A 6 or 10 pin header on
    the application board is all you need for low voltage in circuit
    programming.

    Fast, one instruction per clock cycle.

    30 different processors from 8 pin to 40 pin.

    Flash, Ram, EEprom.

    Check it out;

    http://www.avrfreaks.net/

    and

    http://www.atmel.com/

    Jay
     
  3. Rich Webb

    Rich Webb Guest

    Still, having a development board does remove one very large variable
    from trying to bring up a new processor for the first time.
    Unless you have specific requirements to the contrary, you probably want
    to start with a uC that is in-system programmable. Given that, you are
    free to build it into the board of your choice.
    A slightly smaller subset of in-system programmable devices can be
    programmed with a serial bootloader. They may have the capability to use
    a serial bootloader but the off-the-shelf new devices don't have the
    bootloader pre-installed.
    A direct USB interface is much rarer then even the serial bootloader.
    You can find plenty of designs on the 'net for programmers for the
    various families but the home-made units are usually family specific.
    Even though you're not enthusiastic about the idea, I'd still recommend
    starting with a development board, specifically the Atmel STK-500. It
    supports all of the DIP-formfactor AVR chips and can also be used to
    program in-system to a device on another board. Atmel also has a plain
    old in-system programming pod (AVRISP) that's quite inexpensive. There
    are also build-your-own AVR programmers. See www.avrfreaks.com for much
    more information.
     
  4. Alex Gibson

    Alex Gibson Guest

    I'd second this.

    stk500 is really nice to work with.
    For protyping with it, easiest option
    is get some of the baritek plugin proto boards
    http://www.baritek.com/stk_proto_1.htm

    To get started www.avrfreaks.com



    If thats a bit expensive, the dontronics simmstick
    boards are easy to use.
    http://www.dontronics.com/auto.html
    http://www.dontronics.com/dt006.html
    http://www.dontronics.com/ssinfo.html


    For pics (microchip pic) see the piclist www.piclist.com

    Laying out your own board won't really teach you that much about the
    microcontroller other than ports and some of the characteristics.

    Best way is write code and debug it.

    Start by downloading some of the beginners type code on avrfraks under projects under academy.
    compile then simulate them in avr studio4(4 is nicer for beginners).

    Then start modifying the programs to do other things.

    Alex


    Alex
     
  5. happyhobit

    happyhobit Guest

    Me, I like to "Do It Yourself"

    A proto-board for an ATTiny-12(5 I/O, internal clock) requires a 8-pin
    socket and an ISP header. You'll need a power supply and some I/O (a
    battery, push buttons and LED's). For a microcontroller to run an LCD
    display I used an AT90S1200(15 I/O). That would require a 20-pin socket, a
    crystal and a couple of caps and an ISP header. The parallel port
    programmer I built used 4 resisters, a 25 pin connector and a ribbon cable
    and connector for the ISP header. KISS

    Buying stuff is fine, knowing how it works is better. Just my opinion. I've
    been playing with micros since the '70's.

    Jay

    P.S. My tale of woe in purchasing off the shelf products.

    I bought a programming dongle(pod?) and Proto-board from a distributor and
    they even included a microcontroller, an AT90S2343 (total cost including
    shipping $32). Problem was the microcontroller wasn't compatible with the
    proto-board. The proto-board had a 10 MHz crystal and the 2343, of course,
    won't work with a crystal, not a big help.

    I then built my own Dongle and proto-board and got them working. Then by
    reverse engineering, and a lot of reading, determined the problem with my
    original purchase.

    I contacted the manufacturer and pointed out that their claim that the 2343
    would work on their board was wrong. I contacted the distributor and told
    them that the board and chip they were selling wouldn't work together. The
    manufacturer and distributor ignored me and are still claiming and selling
    as before. (Olimex Ltd and Spark Fun Electronics)

    I'm sure that the STK-500 wouldn't have these problems. Just let the buyer
    beware.
     
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