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[OT?] Looking for a large FIFO subsystem

Discussion in 'Embedded' started by Richard Owlett, Nov 11, 2005.

  1. Minimalist description:
    RS-232 byte serial input {4800 baud needed, higher speeds desirable}
    10 MByte non-volatile memory
    Byte serial output {USB preferred, RS232 acceptable}
    LOW cost

    Minimalist operational description:
    Operator choses record/playback before applying power/start
    If in:
    record mode data appended to existing data
    playback mode all recorded data dumped
    Operator may chose reset which erases _ALL_ data and resets any
    internal pointers to "zero"

    -- These erasures should occur no more frequently than once or twice per
    day and presumed unit useful life not presumed to be more than 3 yrs.

    What I envisage:

    A system with UART and NOR Flash with FPGA for "glue logic"
    Erasure times of "few" minutes would be acceptable

    My personal application:
    Input would be from a GPS mouse receiver.
    Once a day I would dump data to my PC, followed by erase cycle.
    I'm assuming a receiver giving updates once/second.

    I've found products that come near (if not close) but they insist on
    Bluetooth which is *UNACCEPTABLE* to me. Others are too volatile.

    Thank you.
    Richard Owlett, Nov 11, 2005
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  2. Richard Owlett

    cbarn24050 Guest

    Mcrocontroller,ram, battery is all you need.
    cbarn24050, Nov 12, 2005
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  3. Sorry, I should have made clear I was looking for something off the shelf.
    Richard Owlett, Nov 12, 2005
  4. Richard Owlett

    cbarn24050 Guest

    As you specified the internal components i assumed you wanted to make
    it yourself. You seem to be descibing a data logger you might look at
    that. It's a pretty trivial to make yourself (depending on your exact
    spec) or you get someone to make them for you.
    cbarn24050, Nov 12, 2005
  5. Hello

    I need some more information before I can help you.

    Do you want it to be a portable unit or fixed in a car?

    What is the name of the GPS reciever that you want to use?

    What kind of power supply is available?

    Rune Christensen
    Rune Christensen, Nov 12, 2005
  6. Portable, but need not be battery powered. Used in car would be powered
    thru cigarette lighter adapter. Otherwise powered by a wall wart.
    I was thinking any of any of the GPS mouse receivers.
    nominal 12 VDC

    As I'm looking for only a couple of units, I was looking for something
    on the retail market.

    As someone else has pointed out it would be simple enough to build.
    I haven't done any component level hardware in `30 years. I would even
    have to go out and buy a soldering iron ;)

    thank you
    Richard Owlett, Nov 12, 2005
  7. I think the best solution will be a microcontroller connected to a MMC

    For example you could use the microcontroller board

    The microcontroller board has a serial connection and a USB connection.
    The prototype board has a MMC/SD socket. The cost of this two boards
    together with a LPC2138 is 53 EUR.

    You will be able to produce a prototype on this system but I don't think
    it will be the best system for the final product.

    Another solution could be a PDA with a serial port and a compact flash

    Yet another solution could be

    There is just one problem with all this solutions there is no ready to
    use firmware. You need to develop the firmware.

    Rune Christensen
    Rune Christensen, Nov 12, 2005
  8. Richard Owlett

    Donald Guest


    Does your solution meet the OPs "low cost" requirement ??

    If the OP would please let us know if he is looking for a
    complete and running Off-The-Shelf system that logs RS-232 data
    ( from any source ) or is looking for a Do-It-Yourself solution.

    $95 for the 128MMC hardware,
    $139 for FAT file system,
    OPs time to learn the systems involved and code this up himself.

    It would seem if the OP would like to code something up himself,
    (I assume the OP has some idea how to do that)

    To keep the cost and time down ( time is money ).
    It would be quicker to build a smaller version that has just a
    micro ( AVR, PIC,etc) latches for address and data lines, then
    just use a big flash chip. Capture serial data into the flash.
    Simple command parser would allow to retrieve the data at a
    later date.

    Just my simple idea.

    Donald, Nov 12, 2005
  9. I found a commercial product

    Rune Christensen
    Rune Christensen, Nov 12, 2005
  10. That's almost exactly what I was envisioning. But faster and more
    storage capacity ;) Least expensive unit listed on their oder page is
    for a 128MB unit which is 10X what I need. The descriptive portion of
    page lists 32MB as smallest - price differential probably would not be

    I'll also take a closer look at the boards mentioned in your previous
    post. Software creation not a problem as I'm doing this as a personal
    project so I can legitimately cost out my time as "no cost". Might
    actually list it as "negative cost" due to value of the learning experience.

    Thank you
    Richard Owlett, Nov 12, 2005
  11. Richard Owlett

    Kevin Bagust Guest

    You may want to at a hand held GPS rather than building something
    yourself. I know the Garmin hand held GPSs have a track faculty which
    with the correct software you can then download to a PC.

    For software have a look at:

    And try searching on the web for GPS Track.

    Kevin Bagust, Nov 13, 2005
  12. No to handhold GPS.
    Yes to not building hardware myself.
    My interest has very little to do with the navigation ;}

    My original interest in GPS was to to "prove" to my supervisor that I
    was expeditiously completing my route of 4-12 stops, 400-550 miles, over
    10-14 hours. That 14 hour + travel time to my desktop did in most of the
    hand helds. I also could not determine that timestamps were saved with
    the so called "bread crumbs".

    As I learned more I became fascinated with error terms and their
    periodicity. There were scatter plots of horizontal errors. There were
    plots of error magnitude versus time. I wanted x, y, z versus time and
    for multiple days.

    If I use a non-WAAS receiver I bet I'll "discover" a primary variation
    with a 24 hr period ;}

    Rune Christensen referred me to "AntiLog RS232 data logger"
    http://www.zen30649.zen.co.uk/product_antilog.html . That with a GPS
    mouse seems functionally ideal. Costs more than I was hoping for.
    Richard Owlett, Nov 13, 2005
  13. I have found another microcontroller board
    It's a kit that need to be assembled :-( but it's cheap.

    Another possible solution could be this board

    Rune Christensen
    Rune Christensen, Nov 13, 2005
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