P4S533 USB header pin assignments

Discussion in 'Asus' started by Krick, Nov 16, 2003.

  1. Krick

    Krick Guest

    I successfully connected an Antec EasyUSB 2.0 unit to one of the
    motherboard headers on my ASUS P4S533.

    The default wiring that came with the unit didn't work at all. In
    fact, hooking it up disabled all my USB ports.

    The antec unit's cable had the following pinout:

    red: 6 1 :empty
    white: 7 2 :yellow
    green: 8 3 :grey
    black: 9 4 :black
    key:10 5 :blue

    Looking at the small circuit board where the USB ports are attached,
    pins #6 and #1 are connected (USB POWER) and pins #9, #4, and #5 are
    connected (GND)

    Aparently, on the P4S533, pin 5 is something special called OC1# that
    doesn't like being connected to ground.

    So after looking at the USB pinout from my P4S533 manual, I decided to
    modify the USB cable by moving the blue wire from pin #5 to pin #1. I
    could have also just removed it completely but then I would have had
    to cut the wire or insulated it with tape or something. Moving it was
    just easier and it gives me a dual USB power wire.

    new pinout:

    red: 6 1 :blue
    white: 7 2 :yellow
    green: 8 3 :grey
    black: 9 4 :black
    key:10 5 :empty

    Now it works like a charm.

    Krick, Nov 16, 2003
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  2. Krick

    Paul Guest

    With regard to the original comment "motherboard manual must be incorrect",
    so far the stuff I've been reading identifies the case manufacturer
    as the negligent party, not the motherboard. Where the motherboard part
    can be misleading, is the cases where it appears there a components on
    the supplied adapter plate, that would be missing if using the case wiring
    instead. For any computer case you buy, I recommend using an ohmmeter to
    verify that the names printed on the case wires correspond to the
    proper pins on the case connector - failure to do this could result
    in a burned peripheral device.

    As for the OC1# pin, I tried looking in the USB 2.0 standard, and
    don't see it mentioned. A guess is it stands for "over current one,
    active low". How this would work is, if the OC1# signal is grounded,
    the motherboard shuts off power to the USB connectors. Most Asus
    motherboards use Polyfuse automatically recovering fuses for this
    function, where protection is needed. I guess this was an attempt to
    get the adapter board to send a signal when an overcurrent situation
    was detected. Leaving this signal alone (i.e. open circuit) is a
    good idea.

    Paul, Nov 16, 2003
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  3. There was a chinese manufacturer that made a whole batch of USB
    connectors incorrectly wired. About 1 million connectors, and most of
    them went to Taiwan case maunfacturers.

    Be extremely careful when wiring front panel USB connectors to a
    motherboard. If you get it wrong (regarless of whose mistake it was),
    you can fry both the USB device and the motherboard USB port the first
    time that you TRY to use it (depends, of course, on just HOW you "got it
    Barry Watzman, Nov 19, 2003
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