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Good entry level uC?

Discussion in 'Electronic Basics' started by Jacobe Hazzard, Oct 4, 2003.

  1. I am looking for a good uC to use in some autonomous robot projects I have.
    The last time I looked into the scene, PICs were very popular, and the 16F84
    especially so for hobby use. The impression I get now is that people find
    PICs lacking in power, quircky in architecture, and this particular chip
    expensive/obsolete. Is this wrong?

    In order of priority, I am looking for a re-usable flash uC, *inexpensive*
    and easy to find (IE Digikey or similar), preferably with free development
    tools and the possibility of my building a simple, inexpensive programmer.
    Development tools ideally would let me code in C or even basic, but ASM is
    tolerable. I don't anticipate needing any features like super-high clock
    speed, ultra-low power or sleep mode, ADCs or DACs, zillions of IO lines,
    huge EEPROM or program memory or RAM, DSP or anything like that. Basically
    I have in mind tasks that could be performed by discrete logic, but I want
    to simplify the hardware and make it easier to upgrade/make changes. If the
    development environment and programmer also worked for a family of parts,
    some of which have these features, thats a bonus.

    Yeah, inexpensive is the most important thing (no BASIC stamps for me). Any
    suggestions to help me narrow the search would be really appreciated, I
    guess I'll be looking at PICs, AVR, maybe motorola?

    Adam
     
  2. Garrett Mace

    Garrett Mace Guest

    speed, ultra-low power or sleep mode, ADCs or DACs, zillions of IO lines,

    I like the 8-bit Motorola 68HC08 and HC05 families. They are nice to code
    for, programmable in-circuit, and have a really wide range of features. You
    can get them as small as an 8-pin DIP, up to a QFP with lots of I/O, PWMs
    and interface options like USB. The tools are free as long you you can code
    in assembly. It's not that scary.

    Since you mention reducing discrete logic functions to a single, upgradable
    package, I can't let you go without mentioning PLDs. That's what they do,
    and they're quite useful. Read up on Lattice Semi's website, look for the
    ispGAL series, which is a good place to start. Basically they throw you a
    part with a bunch of I/O pins on it, you write a description of the logic
    behavior you want from input to output, and there you go. In a simple 22V10
    you can replace half a board full of logic chips, sometimes. Make a PWM,
    oddly-configured dual counter, serial-to-parallel with a decode output when
    a certain pattern is present, etc. When you outgrow one of those, there is
    always a more powerful one to use.
     
  3. Don't use the 16F84 ! It's old, cost a lot and don't have the features
    of
    the later PICs. The 16F628 is a nice replacement, runs the F84 code with
    minor adjustments, sheeper and has more peripherials.
    Not generaly.
    Correct, don't use *that* [16F84] one.
    PIC ?
    They are free from Microchip
    There are many, I use the Wisp628 :
    http://www.voti.nl/wisp628/index.html.

    OK for both the free Microchipo tools and the Wips628.

    Jan-Erik.
     
  4. happyhobit

    happyhobit Guest

    Hi Adam,

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

    Fast, one instruction per clock cycle. Over 30 different processors from 8
    pin to 40 pin. Flash, Ram, EEprom

    You can be programming for $11, for everything. You can solder, yes?

    Check out AVR Freaks, http://www.avrfreaks.net/

    The Atmel homepage, http://www.atmel.com/

    Jay
     
  5. Thanks for the tips. It looks like I can modify my old discrete 16F84
    programmer to work with the 16F628, and best of all Microchip is sending me
    three sample chips! I also like the look of the JAL assembler on the page
    you linked, and since all of these things are free, I am leaning heavily
    towards a PIC solution. Will definately check out some other product lines
    before investing too much time, but free is hard to beat.

    Adam
     
  6. Did you have a specific programmer in mind for $11? The list at the
    avrfreaks site is pretty intimidating, and seems to be only ready-made
    products available for purchase. A build it yourself serial ISP would be
    awesome.

    Adam
     
  7. happyhobit

    happyhobit Guest

    Hi Adam,

    No, I meant programmer, development board, CPU and power supply for $11.00.

    First the programmer. Cost $4.11 USD

    The simplest programmer to build would be the ‘Jesper’s Original’ parallel
    port programmer. I soldered a 25 pin d-shell plug to a ½ a Rat Shack
    protoboard with 4 100-ohm resisters and a ribbon-cable to a 10 pin header
    for ISP.

    http://www.myplace.nu/avr/yaap/if_jesper.gif

    ‘Jesper’s Original’ parallel port programmer Is STK200+ compatible.

    Not parallel port programmers are equal. Different parallel port programmers
    use different I/O lines and will not work with all programming software or
    hardware.

    I use the CodeVisionAVR chip programmer Kanda STK200+/300. I don’t use
    CodeVision for developing the program, just for burning the chip.

    Jay
     
  8. Rileyesi

    Rileyesi Guest

    I like the Atmel AVR micros. Also, I would suggest you look at www.mcselec.com
    for a BASIC compiler called BASCOM. Free demo software and the liscensed
    software is only like $60 US. The demo only limits the size of the program you
    can write, I think. Tons of support.
     
  9. Guest



    I would stick with either the AVR or the PIC, primarily because the
    number of enthusiasts using these devices is enormous, and the general
    support for all of the ranges is immense, including free tools and
    code snippets etc. Programmers for any of the ranges are easily home
    built for very little money and most of the code you write can be
    ported to a higher range when the need arises without too much
    trouble. Device cost isn't bad either, and there are free samples
    available for all of them, so getting started with either type will be
    easy as well. There are devices from loads of other manufacturers
    available too, for example, Zilog, Texas Instruments and Hitachi to
    name a couple. All with various features etc, so some of them may be
    worth looking at as well.


    regards
    Alastair
     
  10. onestone

    onestone Guest

    My part of preference right now is the MSP430F149 from Ti. A programmer
    costs US$9.95 from Olimex. The rst of the tools, including limited 94k)
    C compiler can be downloaded from thre Ti website. It costs around $7.
    It has the following features:-

    48 I/O
    8 x 12 bit A/D
    very low power consumption
    2 x UART/SPI
    60k Flash
    2K RAM
    On chip JTAG debugger
    Two separate crystals if required
    built in DCO oscillator
    one 16 bit timer with 3 captrue/compare/PWM
    one 16 bit timer with 7 of the above
    built in hardware multiplier

    Overkill for what you say you want, but why on earth wouldn't you want
    A/D in a robot? PWM for positional and motor control, other timers for
    digital sensors, A/D for thermal, IR, other optical, moisture, motion,
    etc sensors, straight digital sensing is little more than the old bump
    'n go toys.

    Al
     
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