[stella] Question about Chimera

[Glenn Saunders]

--- Ruffin Bailey <rufwork at hotmail.com> wrote:
> Okay, I realize I'm a part-timer at best and
> therefore not exactly in the
> know, but how the heck is it that you're getting the
> video from the Chimera
> to the screen?

The idea is that Chimera update its internal RAM or a
portion of the 128K of cart RAM during VBLANK.  This
RAM is then read back with a standardized 2600 kernel
designed to work with the Chimera queues (successive
reads to hotspots ala Pitfall II).  2600 games would
also have the option of writing to the bitmap area
manually.  You could avoid queues and lay out memory
just like the Supercharger instead, but the 4K cart
space becomes really cramped if you do that.  The
queues let you hide large datasets behind individual
addresses so you don't have to bankswitch so much.

> Perhaps more succinctly put, is it possible on any
> level to get this sort of
> resolution 

I've never claimed Chimera games could get higher
resolution graphics than the TIA can provide.  But it
could update more of the screen each frame than the
VCS would normally have time for.  So you might indeed
see a visible difference in the kinds of displays it
can generate.  So it would be similar to the benefits
of the DPC chip in Pitfall II, but with the data in
the queues being more dynamically generated.

> Fwiw, to me, if you can load up the Chimera with a
> standard 4k ROM and play
> as if you were on using a standard cart on your 2600
> (as you essentially can
> on the SC), it's a good thing.

Chimera will have some degree of multicart
capabilities, although that is not the main priority.

>  There's nothing about
> adding a processor that says you've got to use it --
> though how could you
> resist using extra RAM?!

If nobody uses these features, it's no tragedy to me. 
We've done the math and it was not really much cheaper
to strip the functionality down any more than this. 
In some cases it's actually more expensive to use
smaller capacity chips!  Such is the world of the 21st
century.

> And why not learn some ARM and think about putting
> together some non-2600
> widget of your own?  Would be a neat way of
> providing, via the 2600, a
> standardized dev platform for a currently cheap &
> available processor.

ARM programming would probably be a worthwhile skill
to learn.

Also, the programming environment on the ARM will be
very cramped.  You can only run ARM code directly out
of the 8K RAM and 32K flash ROM.  So it may not be as
much of a walk in the park as you think.  That's why
I'm trying to make sure there are some useful routines
pre-built into the 32K.


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