Diveide Plus - Sinclair

This is a discussion on Diveide Plus - Sinclair ; If i get one of these with the through conector on and a plus d interface as i gather they can be used together but if i get a bus expander aswell can i use a kempston joystick interface at ...

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Thread: Diveide Plus

  1. Diveide Plus

    If i get one of these with the through conector on and a plus d interface as
    i gather they can be used together but if i get a bus expander aswell can i
    use a kempston joystick interface at the same time, so thats 3 interfaces at
    the same time?


    Regards

    Graham


  2. Re: Diveide Plus

    Graham Prout wrote:
    > If i get one of these with the through conector on and a plus d
    > interface as i gather they can be used together but if i get a bus
    > expander aswell can i use a kempston joystick interface at the same
    > time, so thats 3 interfaces at the same time?
    >
    >
    > Regards
    >
    > Graham


    The PlusD + DivIDE Plus combination is as yet unproven. Rudy Biesma
    (the designer of the +DivIDE firmware) is still researching this.

    You should theoretically be able to use a Kempston joystick interface at
    the same time - we have actually got a joystick interface design with a
    through connector built in, so you could potentially plug the joystick
    interface between the DivIDE Plus and the PlusD or Spectrum and DivIDE
    Plus. However, none of this has been tested and we know that timing
    issues may prevent it from working.

    Interesting times indeed

    Rich Mellor
    http://www.rwapsoftware.co.uk
    - Join our new customer forums: http://www.rwapadventures.com/forums/

  3. Re: Diveide Plus

    I'd also suspect the original 128 k machine may actually freeze.

    Brian

    --
    Brian Gaff....Note, this account does not accept Bcc: email.
    graphics are great, but the blind can't hear them
    Email: briang1@blueyonder.co.uk
    __________________________________________________ __________________________________________________ __________


    "Rich Mellor" wrote in message
    news:4797c8f5$1_4@mk-nntp-2.news.uk.tiscali.com...
    > Graham Prout wrote:
    >> If i get one of these with the through conector on and a plus d interface
    >> as i gather they can be used together but if i get a bus expander aswell
    >> can i use a kempston joystick interface at the same time, so thats 3
    >> interfaces at the same time?
    >>
    >>
    >> Regards
    >>
    >> Graham

    >
    > The PlusD + DivIDE Plus combination is as yet unproven. Rudy Biesma (the
    > designer of the +DivIDE firmware) is still researching this.
    >
    > You should theoretically be able to use a Kempston joystick interface at
    > the same time - we have actually got a joystick interface design with a
    > through connector built in, so you could potentially plug the joystick
    > interface between the DivIDE Plus and the PlusD or Spectrum and DivIDE
    > Plus. However, none of this has been tested and we know that timing
    > issues may prevent it from working.
    >
    > Interesting times indeed
    >
    > Rich Mellor
    > http://www.rwapsoftware.co.uk
    > - Join our new customer forums: http://www.rwapadventures.com/forums/




  4. Re: Diveide Plus

    On 2008-01-23, Rich Mellor wrote:
    > The PlusD + DivIDE Plus combination is as yet unproven. Rudy Biesma
    > (the designer of the +DivIDE firmware) is still researching this.


    You need to have hardware support if you have more than one add-on with
    a shadow ROM to support two shadow ROMs. Otherwise the two add-on will
    probably end up trying to page in at the same time (for instance, they
    will both trap RST 8 calls at the same time, or they'll both trap RST 0
    at the same time). Two ROMs being selected on the bus at the same time
    results in a crash.

    The way I'm supporting add-ons that also have a shadow ROM with the
    Spectranet is to hold A15 high on the through port whenever my ROM is
    paged in, this way the downstream peripheral thinks that upper memory is
    being accessed when my ROM is paged in, and won't try to page in at the
    same time.
    I've tested this with the DivIDE (not the DivIDE Plus yet) and my own
    diags board and the approach seems to work fine - for instance, on
    reset, the Spectranet runs its ROM initialization code first, then
    clears the reset flag in its support logic and unpages with a jump to
    0x0000. With its event flag cleared, it doesn't trap the second reset,
    allowing downstream ROMs to run their initialization code. This whole
    approach could be done in a 'daisy chain' ripple priority system for an
    arbitrary number of peripherals (well, until the A15 line gets delayed
    too much, but the Spectrum will run out of +5v power before that
    happens). RST 8 traps are a bit more awkward, so really only one RST 8
    routine can be active at once and will need manually switching (either
    using a hardware jumper or OUT instruction). NMIs can be treated like
    reset - you can tell if it was your NMI button or not, and therefore
    make a decision on whether to trap or not that way.

    Peripherals like the Kempston don't have a ROM so they are pretty much
    trouble free on a through port.

    --
    From the sunny Isle of Man.
    Yes, the Reply-To email address is valid.

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