[Coco] 8 slot multi pak

[Brian Blake]

Ed... I triple-dog dare you to make one...

On Jan 17, 2017 2:46 PM, "Zippster" <zippster278 at gmail.com> wrote:

> There’s an issue with going beyond 4 slots on an MPI, software support.
>
> The arbitration scheme using *CTS and *SCS traditionally only supports
> for slots, so old software that uses these signals for selecting carts
> would mean
> you’d only be able to use the first four slots and stay compatible.
>
> Also, the *CART interrupt goes to the slot receiving *CTS, so autostart
> carts
> would be limited to the first four slots as well unless the arbitration
> scheme is
> extended.
>
> Now some things don’t use those signals, like the DACs on the Orch90, and
> items
> like that could go into extended slots without changing old software.
>
> A thought that occurs to me is that with the unused bits in the MPI
> register at $FF7F,
> the use of the *CTS/*SCS scheme can be easily extended to as many as 16
> slots.
> In fact, it looks like the bit locations might have been chosen with this
> in mind.
>
> New software could easily support this, and perhaps old software can be
> patched,
> though at some point additional bus buffering may be needed.
>
> Thinking about it more, maybe this isn’t much of an issue.  You’d just
> have to choose
> what slots you use which carts in carefully depending on the software
> you’re using.
>
> Someone please tell me not to make a 16 slot monstrosity just to make use
> of those
> register bits….   lol…  :)
>
> - Ed
>
>
>
> > On Jan 17, 2017, at 12:47 PM, Michael Brant <brant.michael.l at gmail.com>
> wrote:
> >
> > Jim, it was my understanding is that you were building the mpi with the
> > capability for 8 slots via 2 banks of 4.
> >
> > On Jan 17, 2017 1:39 PM, "RETRO Innovations" <go4retro at go4retro.com>
> wrote:
> >
> >> On 1/16/2017 10:40 PM, Brian Goers wrote:
> >>
> >>> What is the status of the 8 slot Multi pak.
> >>> How is the testing going?
> >>>
> >>>
> >> I am finishing the final PCB design to the 4 port unit (with some relays
> >> for power), but I am not aware of any 8 port testing.
> >>
> >>
> >> Jim
> >>
> >>
>
>
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