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Testing Flash Memory Question

Discussion in 'Electronic Design' started by panfilero, Apr 3, 2008.

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  1. panfilero

    panfilero Guest

    I am purchasing a Nand-Flash memory chip.... just stand alone only
    flash... not a microcontroller or anything. I was wondering if anyone
    knew of any interfaces or test boards (maybe they are called flash
    controllers? I'm not sure) that I could use to test the memory...
    basically I will write a little code to read and write, and then check
    that the memory is ok. So far I have found this: which seems
    about right, except that I would prefer to have an ethernet output
    instead of rs-232. Does anyone know of any other boards like this? Or
    if there is a way to convert RS232 to Ethernet?

  2. mike

    mike Guest

    None of my business, but WHY do you need to test it? It's a rhetorical

    "a" chip? like quantity one?
    And if you test it according to vendor specs, how do you expect to get
    anything other than the vendor results?

    Test it in the (mis)application. Your results are likely to be affected
    more by your wear leveling algorithms, noise, timing margins, etc. than
    anything the vendor did.

    While you can easily come up with many counter-examples, the majority of
    vendor parts meet vendor specs when used in conforming environments.

    Ethernet is a horribly complex way to go to test one chip...or any
    number of chips for that matter. USB to RS232 is a lot easier.

    You can buy a USB interface with drivers and everything for dirt cheap.
    Comes with the flash aready installed.
    Called a thumb drive.

    And if you're really talking about vendor qualification to buy zillions
    of 'em,
    the problem is a LOT more complex than you appear to understand.
  3. panfilero

    panfilero Guest

    Well... I just want to test a few, it's for research... I might test
    maybe 10 ICs total. I'm planing on buying several Flash ICs from
    digikey they come in TSOP packages I'll probally get 48pin
    packages.... so, what I'm looking for (and having a hard time finding)
    is something I can plug a Flash IC into and read and write to the IC.
    And I can probally program a microcontroller or something at this
    point to carry out my testing algorithm.... (I hear FPGA might be good
    for this but I'm not familiar with FPGAs).... I'm guessing I need some
    kind of memory controller (I don't know anything about memory
    controllers) if I try to build this myself... I just want a way to
    read and write and perform some error code correction to an individual
    Flash IC.

  4. Bob

    Bob Guest

    how about a flash programmer? We use a Needhams EMP-20. Program it;
    erase it; program it; erase it. The programmer checks for failed bits.
  5. mng

    mng Guest

    The protocol for accessing Flash is pretty straightforward. Just take
    a look at the datasheet. I've done a simple storage board using a PIC.
    Writes to Flash are pretty slow, so speed is not so much an issue.

    But what exactly are you trying to test? Block failure rates?
  6. panfilero

    panfilero Guest

    This sounds interesting, I can't find any documentation about it
  7. panfilero

    panfilero Guest

    Yes I'd like to look at failure rates, see which bits aren't flipping,
    implement an ECC, be able to test with different checkboard patterns
    and things like this.... I'm looking for some kind of test board where
    I could put different Flash packages to be tested....
  8. Guest

    Depending on the sophistication of the IC, there may be substantial
    smarts in between the external interface and the actual memory cells
    which may get in the way of your tests.

    Also, if you are testing to failure you may need a fast interface, or
    be prepared to
    wait a long, long time.
  9. panfilero

    panfilero Guest

    Right, I was thinking that I would have to use a mocrocontroller and
    expand its memory, to inlcude the flash and then I could apply my test
    and verify bits and try out an ECC algorithm.... I've been told FPGAs
    could also be used, and would be favorable... but I have no experience
    with FPGA.... if I go the microcontroller route I would need some kind
    of interface woudln't I? A memory Flash controller or something?
  10. Guest

    The easy way is to find a microcontroller (or I/O expander) that gives
    you enough
    pins, and then talk the flash device's protocol in software. However,
    that's likely
    to be too slow if you expect to wear out a device in less than
    calendar time.

    To go faster you may need some dedicated flash interface logic,
    either purchased or
    built into an FPGA. The FPGA route can be fairly painful, because
    interfacing it
    to a higher level test controller isn't necessary easy, but it is
  11. mng

    mng Guest

    First of all, you should look at a Flash chip datasheet. Learn the
    interface. Look at the timing. You'll have to do the low-level control
    yourself if you want access to the bits, and it's really not as
    complicated as your hesitation suggests it is. Just read the datasheet.
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