unsuscribe
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> De: Mark De Smet <desmet@xxxxxxxxxxxx>
> A: stella@xxxxxxxxxxx
> Asunto: Re: [stella] Cartridge read timing problems?
> Fecha: Martes 20 de Abril de 1999 12:06 PM
>
>
> > Have you tried eliminating the 3 state buffer altogehter? I am not
> > quite clear on exactly what you are doing, but if you just want to
> > selectivly enable each of the other ROMS you should just hook the
> > address and data busses from the cart slot directly to all the roms
> > then just enable the appropriate one onto the data bus using it's chip
> > enable line. The 2600 seems to have pretty good bus drive capabilities
> > since the Supercharger has 3 RAMS, 1 ROM, and the SC custom chip on
> > the bus. If address bus drive becomes a problem you could just throw
> > in an bus buffer IC that is always on to give the lines some extra
> > drive power.
>
> The isolation(the 3 state for the data; and the MUX's for the address)
are
> because the bus with all the roms on it can selectively be switched to be
> connected to the atari or my main processor system(an Intel 80188). This
> is because there is also a bit of SRAM there that I wish my system to be
> able to read/write, and I wish my system to be able to read the contents
> of the ROM's. The system has 2 basic states. 1, where the in-between
bus
> with all the ROM's is connected to the atari, and one of it's chips is
> selected for the atari to run off of. 2, where the in-between bus is
> connected to my main processor bus so it can read/write to it; while the
> atari is running screensaver ROM(that is directly on the atari bus).
> (Yes, the atari is power cycled whenever the states switch)
>
>
> > > Any ideas about what else may cause such software actions?
>
> The thing that really puzzles me is that the games, do mostly run. I
mean
> if my interface didn't meet the timing constraints, I would think that
> there would be many more problems than just graphics issues(like the
> program not starting up).
>
> Mark
>
>
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