Did't one of the cinematronic games that was produced as a b&w game end up
being a color game and worked this way? (I think it was war of the worlds)
Clay, are you going to make this kit
1) cheaper, more accurate, harder to install, Where you attach it to the
input side of the intensity DAC.
or
2) more expensive, less accurate, easy to install, Where you have an ADC
and convert the analog intensity signal back to binary, but can attach it
somewhere downstream from the game PCB.
You could also save a few bucks (cents) by just having single color shots.
-jeff
>The hardware tells you exactly when the beam should be turned on and off
>on the CRT. The game also has to load the "intensity" value for the
>beam. Well, as it turns out, Atari used slightly different intensities
>for a lot of stuff in Asteroids... So, if you take those 4-bit
>"intensity" values and use them as an index for a color lookup table.
>*Viola* color! Just takes something to generate a few bits of output to
>make some resistor dividers for color outputs with some transistors.
>Neat, huh? ;-) Seems like Asteroids only used 7 or 9 intensities very
>often... To make the "flashing" color I had a counter that was
>associated with one particular intensity value and instead of using a
>lookup value for the color map, fed the outputs of a counter there
>instead...
>
>-Clay
jeffh@diac.com
Buy/Sell/Trade Classic Video Arcade Games
www.diac.com/~jeffh/
Received on Fri Jul 31 23:57:54 1998
This archive was generated by hypermail 2.1.8 : Fri Aug 01 2003 - 00:31:26 EDT