>
> Huh? When you do that, you end up with basically random values in all the
> TIA registers, which probably won't change (the CPU will hit a loop or a
> JAM pretty quickly.) If the VSYNC register
> contains zero, then the TV will do its own syncing, for a stable picture
> which will consist of whatever values ended up in the playfield, players,
> etc. If VSYNC is on, the TV won't sync right and the picture will
> probably roll.
Sync automatically?? I thought you *had* to do the vsync ritual to get a
stable display. Hmmm... I wonder if when a TV syncs automatically if they
all end up generating the same number of scan lines before automatically
doing the vertical retrace? Could you do a stable game with automatic
synchronization? Other than a game with one dimensional graphics. Vertical
bars moving back and forth ;-) In fact, there's a little explored 2600
sub-genre. ;-)) One dimensional games with no kernal.
Of course this would make the diagnostics even easier to do. Just clear out
the player graphics and the playfield graphics and set the background color.
Of course I'd also have to modify the emulator to support games that don't
do a vsync!
> A frame of instructions at a time? That's quite a lot, and would involve
> bankswitching on the RAM. It also deprives the helper CPU of the ability
> to read the collision or paddle registers line by line.
>
> > So in this scheme, the host would read the switches and store
> the results
> > somewhere in RAM for the symbiont to see maybe once per frame...
>
> Well, yeah, fine on the switches, if you can get by without collision
> registers or paddles.
Yeah, maybe you would need to do it a line at a time still. But I find
myself wondering what the real advantage of a separate CPU would be? Would
it really be possible to break the mold, or would it still *walk like a
duck* no matter how fast the processor was and how much memory you had?
>
> This *would* allow the helper CPU to generate sound any way it wanted, and
> send it to the TIA at 15 khz or even faster... anyone for a 2600 .WAV
> player? :)
How would this work? By changing the volume register really fast?
John
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