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USB test

Discussion in 'Electronic Design' started by Victor, Mar 15, 2007.

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  1. Victor

    Victor Guest


    I'm searching for a PC software that to send commands through a USB port.
    Does anyone know about one ?

  2. Rich Grise

    Rich Grise Guest

  3. Venica

    Venica Guest

  4. Joel Kolstad

    Joel Kolstad Guest

    I'm assuming you mean, "from user mode?" If you only want to talk to HID
    devices, in Windows XP and above you don't need any software -- it's built
    into the OS. For arbitrary devices and commands, I've used DriverX USB in
    the past, but it's not free. I believe there are some open-source packages
    out there that do roughly the same thing, however -- I'm certain there are
    for Linux, if that'll work for you.

    I also seem to recall that supposedly in Vista there were going to open up
    USB more completely in user mode, but I could just be making that up.

  5. Victor

    Victor Guest

    Joel Kolstad a écrit :
    I don't understand what do you mean by "in Windows XP and above you
    don't need any software"...
    In fact I'm searching for something like "Docklight" but for USB...
  6. The problem here is that USB, is not a simple interface like the serial
    port. Everything is packetised, and involves layers of negotiation from
    both ends. The 'host', will normally send a packet, with a type,
    direction, device address, and endpoint number defined. Then there is a
    packet either to or from the host (depending on direction), or a 'no data'
    indication. Then there is an acknowledgement from the other end. There are
    more complex forms with an extra packet.
    At the driver 'end', there is the USB stack (handling the packets), and
    then the PC side driver, talking to this.
    There are a number of 'standard' packet forms (HID device etc.), where the
    driver is present in Windows, and the simplest USB implementations, will
    take advantage of these. A lot of the initial communication, is the same
    whatever the device, so the hub driver, will receive a notification when a
    device is attached, and automatically develops a 'request device
    identifier' packet, and then sets up the initial 'pipe'.
    A connection to a specific device, is a 'pipe', and you can generate an
    IRP (I/O request packet), to the PC host controller, which then handles
    the physical translation across the USB interface.
    So the problem is that you can't just 'send a command', and expect
    anything to happen. There has to be a complete packet, with all the
    handling associated with this, and several parts of this will
    automatically happen when a device is attached, without any further
    software being needed.
    There are dozens of 'USB monitor' applications (some free), which allow
    you to snoop on the transactions, and in some cases allow them to be
    displayed ordered by device, and command type. These are pretty much
    essential when configuring a new device.

    Best Wishes
  7. Victor

    Victor Guest

    Roger Hamlett a écrit :
    Hi Roger and many thanks for all the explanations! I don't know much
    about USB and thought I could find something like it exists for RS232.
    In fact I'm working on a project that involves a PICDEM FS USB board
    (from Microchip) and in a older project an ex-colleague was using a
    basic GUI (using .NET) to send commands to the same board.

    The problem now, is that we don't have the source code anymore (anyway I
    haven't got a clue about programming with .NET...:) and the executable
    is a little useless for me and moreover I can't get it working since it
    throws me a "SecurityException" as soon as I run it.

    Well, I've found something using Java (javax.usb) so I'll try a little
    that way...

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