USB host, the quest - Hewlett Packard

This is a discussion on USB host, the quest - Hewlett Packard ; The USB host question comes back one more time. This time I simply want to say that it should be possible to run at least a couple of simple experiments. I saw on a website a 4-port USB hub (Ultra ...

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  1. USB host, the quest

    The USB host question comes back one more time. This time I simply
    want to say that it should be possible to run at least a couple of
    simple experiments.
    I saw on a website a 4-port USB hub (Ultra brand) that doesn't take
    power from the host, it comes with a separate power supply.
    So, at least it should be possible to run some experiments with USB
    host mode, what's needed is:

    * The USB hub w/external power (US $ 19)
    * A female 2 female USB A gender changer (US $ 2.50)
    * HPGCC
    * A few USB manuals
    * A lot of patience


    Anyone willing to try?

    Claudio


  2. Re: USB host, the quest


    "Claudio Lapilli" wrote in message
    news:1175434359.936732.247510@b75g2000hsg.googlegr oups.com...
    > The USB host question comes back one more time. This time I simply
    > want to say that it should be possible to run at least a couple of
    > simple experiments.
    > I saw on a website a 4-port USB hub (Ultra brand) that doesn't take
    > power from the host, it comes with a separate power supply.
    > So, at least it should be possible to run some experiments with USB
    > host mode, what's needed is:
    >
    > * The USB hub w/external power (US $ 19)
    > * A female 2 female USB A gender changer (US $ 2.50)
    > * HPGCC
    > * A few USB manuals
    > * A lot of patience
    >
    >
    > Anyone willing to try?


    Hello Claudio,
    that would make a nice project, not that i want to discurrage the effort but
    i have my
    doubts so if somone is interested read the following :

    (I have a "couple of general USB manuals" but finaly i need device specific
    documentation
    to complete a driver to see if it realy works -which seams harder to get)

    In case if i tried to put USB host to use i would take more direct approach
    I would take a mouse -power it trough 5V adapter and plug it directly into
    calculator USB *data* lines.
    (I suspect when going trough USB hub, additional things must be taken care
    of,
    for first experiments i would prefere to stay as basic as possible and avoid
    everything which can be avoided)

    When these tests would be a success i would consider to write a general host
    driver (or at least general part of it).
    When this is done i would realize that it's just a calculator and i doubt if
    people need USB host on it.
    People who need it, would generaly not be able to find information for their
    device most probably would not be
    able to write the device specific part of the driver so, basically... it's a
    dead end !

    On the other hand IrDA and Serial are sufficient for most applications.
    Serial -even as it is:
    when you interface with some pic or microcontroller based board with "RS232"
    creation of your own
    will generaly have compatible (controller's logic) levels. Communication
    between 50Gs works,
    some instruments can be moded themselves (bypass the level shifter) to
    deliver compatible levels so...
    TW based his solution on IrDA which is great (electrically decoupled from
    calculator's sensitive data lines),
    at the same time 115k is nice transfer rate.

    Maybe SDIO would be more interesting,
    but then external SDIO devices are not as popular as one would expect so...

    maybe modding the HP50 hardware to make it run WM5 or WM6 would
    be more interesting but then HTC is making great producs
    -just the kind VPN and I were lamenting about on and on and on... :-)

    manjo



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