Direct control of the usb data line drivers - Hardware

This is a discussion on Direct control of the usb data line drivers - Hardware ; Dear Linux-Hardware-Freaks, is there any possibility to directly access the usb D+/D- line drivers ? After looking into the electrical specifications of the intel USB 1.1 document, I found out that there is a line driver with differential-one, differential-zero and ...

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Thread: Direct control of the usb data line drivers

  1. Direct control of the usb data line drivers

    Dear Linux-Hardware-Freaks,

    is there any possibility to directly access the usb D+/D- line drivers ?

    After looking into the electrical specifications of the intel USB 1.1 document, I found out that there is a line driver with differential-one, differential-zero and SE0 - state, an output-enable and the controller includes one differential receiver and also two single-ended receivers for the D+/D- lines.

    How may I control there features directly, it is possible to disable the hardware-implemented usb-protocoll, especially in the uhci 1.1 host controller chips ?

    Best regards,
    Matthias Koch
    Germany

  2. Re: Direct control of the usb data line drivers

    Matthias Koch wrote:
    > is there any possibility to directly access the usb D+/D- line drivers ?


    Not from software.

    > How may I control there features directly, it is possible to disable
    > the hardware-implemented usb-protocoll, especially in the uhci 1.1 host
    > controller chips?


    No. The most you could do is to use some feature from the USB
    specification, e.g., you could tell the HC to apply suspend or reset
    signaling to a port.

    UHCI allow to read the level of the two data lines (bits 4, 5 in the
    PORTSC registers), but these bits are only updated at the end of a
    frame.


    Regards,
    Clemens

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