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ide to usb controller - HD rack :)

Discussion in 'Electronic Design' started by starchild, Mar 30, 2007.

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  1. starchild

    starchild Guest

    Hello Engineers! :)

    I am interested about making a hard disk rack...ie connecting about
    eight hard disks simultaneously to a personal computer via the usb
    port. I think the second part is easy, just make eight ide to usb
    controllers and connect them to a usb hub.

    Any proposals about the structure of the project? Or where I can find
    any information, schematics, *reference* for these protocols and
    interconnections? Is is possible to use an ATMega or is it better to
    use a Cyclone FPGA?

    I don't want to take a ready-made solution...and this is the only
    think Google and newsgroups return!

    Thank you again!
     
  2. Joel Kolstad

    Joel Kolstad Guest

    USB.org will get you to the protocol for disk-type devices.
    Well... do you care about performance? All the ATmegas with USB interfaces
    are USB 1.1 (12Mbps), whereas you *might* have a shot at getting USB 2.0
    (480Mbps) speeds out of an FPGA... but probably not with the cheaper/slower
    speeds grades. (Traditionally this problem was solved with a "SerDes" that
    would do the high-speed serialization/deserialization for you and present and
    accept parallel data at a much lower clock rate, but AFAIK such ICs don't
    exist for USB 2.0.)

    This is a very large project you're undertaking, if you insist on doing it
    "from scratch" don't have prior experience interfacing to USB or hard drives.
    You're talking many months of effort here...
    What's your goal? To learn about USB? Hard drive interfacing?

    ---Joel
     
  3. John Barrett

    John Barrett Guest

    For implementation reference:

    http://www.lvr.com/usbms.htm

    you can find sources for the usb/ide chips and usb hub chips easy enough I
    suppose if you want to get it all on one board instead of stringing usb
    cables around the chassis

    http://atmel.com/dyn/resources/prod_documents/doc1137.pdf
    http://www.lvr.com/usbchips.htm

    or

    http://www.opencores.org has everything you need for IDE and USB on
    FPGA/CPLD... that will leave you with integrating an MCU core and writing
    the code to make it functional. you could expose individial drives or make a
    USB/IDE raid controller.
     
  4. jasen

    jasen Guest

    As I understand it USB has a maximum 4-way fanout per hub so you'll need
    three hubs to get one usb cable to 8 drives it's probably possible to put
    all three hubs on a single chip

    have you considered using SATA instead of IDE, you could use SATA instead of
    USB too for that matter....
    start adding "datasheet" or "schematic" to your searches

    Bye.
    Jasen
     
  5. starchild

    starchild Guest

    I didn't have examined the SATA solution. I think it gives more
    expandibility...though I have to do a research about the protocol.
    Thank you all for your replies, I will have more news soon! :)
     
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