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    SubjectRe: [2.1.65] New patch for serial port IRQ setup.
    Date
    From
    Alan Cox wrote:
    >
    > > I've been made aware that some manufacturers of internal modems recommend
    > > using irq 2 for COM 4, while other recommende using irq 9. I've made this
    > > a configuration option.
    >
    > You cannot share ISA interrupts between two standard seperate ISA cards
    > in general. The way the cards are wired means that whoever has the strongest
    > drivers sets the interrupt level.

    Talking about sharing ISA interrupts, has PNP changed any of this?
    This would've been a good time to change that situation: specify that
    when in level triggered interrupt mode each card provides a pull-up,
    and an active-low (if the lines are active-low). The pullup should be
    specified to be 1/5th of the minimum requires sink current, allowing
    upto 5 pull-up resistors in series: 5 cards can share an interrrupt.


    Roger.


    --
    ** R.E.Wolff@BitWizard.nl ** +31-15-2137555 ** http://www.BitWizard.nl/ **
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