[stella] Trackball coprocessor

Subject: [stella] Trackball coprocessor
From: Glenn Saunders <cybpunks2@xxxxxxxxxxxxx>
Date: Thu, 04 Jul 2002 22:43:41 -0700
How hard do you think it would be to make a microcontroller that could poll a high-resolution trackball or roller controller FOR the 2600 so that the 2600 would only need to poll it once per frame? The microcontroller would return back all the data that was missed by not reading during the screen. I'm just thinking that if there was a way to implement some kind of handshaking with such a microcontroller so that it passed back a direction and a delta since the last read, that you'd get the best possible results. I'm pretty sure that's how most classic hardware does it, i.e. dedicated hardware that constantly polls the controller rather than the main CPU. POKEY does this to simplify paddle reads for the Atari 8-bit, for instance.

With only 4 bits to work with you'd only be able to yield 8 pixels of movement maximum per frame for a driving controller. That means a total of 64 positions per 360' rotation instead of 16. That would probably be enough for Tempest. Maybe not quite enough for this one.

You'd only yield 4 with a trackball. If you used both controller ports you could double that, but sacrifice 2-player simultaneous games. Or if it were possible to spool the data back in two or more nibbles at a time then you could have it buffer as large a number as you wanted.

It would be really cool to play 2600 games with the precision of a Logitech Mouseman without big kernel sacrifices. We could also go back and hack Missile Command, Centipede, Millipede, Gyruss, and Reactor...

Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/

Current Thread