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ARC-OTG USB question

Discussion in 'Embedded' started by Lee Thalblum, Jun 5, 2009.

  1. Lee Thalblum

    Lee Thalblum Guest

    Hi everyone,

    I'm working on a linux device driver for an Arm based USB device. I've
    got an ARC-OTG USB controller and an ISP1504 compatable transciever.
    I'm trying to find out how to switch from full speed to high speed
    when the host starts negotiation. I've looked through the USB
    controller data sheet, and I dont see anything that allows me to
    change speed, besides test mode. Is the controller responsible for
    doing the speed negotiation? Or does the driver code handle this
    itself? I've looked through other driver code for the ARC-OTG block
    with no luck. Any suggestions would be greatly appreciated. Thanks.

    Lee Thalblum, Jun 5, 2009
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  2. Op Fri, 05 Jun 2009 16:22:33 +0200 schreef Lee Thalblum
    "Transition to high-speed signaling is accomplished by means of a low
    level electrical protocol which occurs during Reset."
    - Universal Serial Bus Specification Revision 2.0, paragraph
    "Connect and Disconnect Signaling"
    Boudewijn Dijkstra, Jun 11, 2009
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  3. Lee Thalblum

    Lee Thalblum Guest

    Yes, I've read the spec and understand the protocol. My question is,
    is this handled by the ccontroller, or does the driver have to handle
    this in software? I dont see anything in the controller data sheet
    that addresses this either way.
    Lee Thalblum, Jun 11, 2009
  4. Op Thu, 11 Jun 2009 14:24:15 +0200 schreef Lee Thalblum
    I expect both ARC and your USB protocol analyzer to be able to provide the
    necessary information.
    Boudewijn Dijkstra, Jun 11, 2009
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