connecting constant to inout port

From: Shalom Bresticker (Shalom.Bresticker@freescale.com)
Date: Thu Oct 21 2004 - 02:36:34 PDT

  • Next message: Steven Sharp: "Re: connecting constant to inout port"

    I had an interesting case yesterday.

    I'd like to hear what others think.

    There was a module with an inout port.

    In this case, the condition driving the inout port from within the module is
    disabled,
    so that it is effectively an input port only.

    Externally, it was connected to a constant value of the form 2'b01.

    One simulator reported a compilation error (claiming it was not able to do
    collapsing of the port),
    a second simulator reported a warning.

    Strictly, according to the LRM, it is indeed illegal.
    Should it be?

    I'm not proposing we actually change the standard on this point,
    but I'd like to hear a theoretical answer.

    Thanks,
    Shalom 

    --
Shalom Bresticker                        Shalom.Bresticker @freescale.com
Design & Verification Methodology                    Tel: +972 9  9522268
Freescale Semiconductor Israel, Ltd.                 Fax: +972 9  9522890
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