COM3 I/O port - VxWorks

This is a discussion on COM3 I/O port - VxWorks ; I am trying to get COM3 working running vxworks 6.x on an Intel processor. The code base I have uses the vxBus method for configuring the COM devices. The ICH is an ICH7 connected to a winbond superIO chip. I ...

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Thread: COM3 I/O port

  1. COM3 I/O port

    I am trying to get COM3 working running vxworks 6.x on an Intel
    processor.

    The code base I have uses the vxBus method for configuring the COM
    devices. The ICH is an ICH7 connected to a winbond superIO chip.

    I am able to configure the superIO chip (logical device 6 is UART C)
    and read back the correct values. I set UART C to use I/O port 0x3e8
    which I believe is standard for COM3.

    The problem is, while I can program and enable UART C on the superIO
    chip, I am unable to access the device using I/O address 0x3e8. Seems
    like the I/O decode for that address is not active.

    I took a close look at the ICH7 and see that "COMA" and "COMB" are
    enabled and set to the correct I/O ports but there is no specific bit
    for COMC? I tried playing with the generic I/O decode registers on
    the LPC bridge but that seems to have no effect.

    Anyone have some knowledge on this somewhat esoteric issue?

    Thanks.

  2. Re: COM3 I/O port

    On Aug 19, 8:21*pm, fenwayfool wrote:
    > I am trying to get COM3 working running vxworks 6.x on an Intel
    > processor.
    >
    > The code base I have uses the vxBus method for configuring the COM
    > devices. *The ICH is an ICH7 connected to a winbond superIO chip.
    >
    > I am able to configure the superIO chip (logical device 6 is UART C)
    > and read back the correct values. *I set UART C to use I/O port 0x3e8
    > which I believe is standard for COM3.
    >
    > The problem is, while I can program and enable UART C on the superIO
    > chip, I am unable to access the device using I/O address 0x3e8. *Seems
    > like the I/O decode for that address is not active.
    >
    > I took a close look at the ICH7 and see that "COMA" and "COMB" are
    > enabled and set to the correct I/O ports but there is no specific bit
    > for COMC? *I tried playing with the generic I/O decode registers on
    > the LPC bridge but that seems to have no effect.
    >
    > Anyone have some knowledge on this somewhat esoteric issue?
    >
    > Thanks.


    I forgot to add that I have indeed updated hwconf.c. Seems the probe
    call fails when it tries to see if the COM3 device is actually there.
    I believe it is simply writing a value to the interrupt register for
    superIO logical device 6 and reading it back... but that fails. All
    we read for I/O port 0x3e8 is 0xff.

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