RE: PC Vector generator card... (and ESB update)

> so, do it already! what are you going to drive the z axis with?
>
Right now I've got three 4-bit D/A's built from common value resistors
and 2N3904 transistors (one each) set to RGB-color gun levels. An
external bus access is actually 24 bits wide, so I can add more bits for
each color gun, or maybe use 5 or 6 bits for an overall "intensity"
setting for all color guns ('ala Atari's 8-bit intensity control for
Z-correction in the AVG design.)

I'm not planning on including a z-blank control for the color outputs.
With a 30ns instruction cycle I figure I'll have time to turn the color
guns off if they need to be off... *laugh*

I think as long as I have the equivalent of 8-bit color resolution
that'll be good enough for starters-- subtle color variations are not
the vector monitor's strong suit. That's all the more EMU and MAME use
and they look pretty good. (For using new-fangled raster-display stuff
anyway. ;-)

I'm really liking the idea of downloading the DSP's program code from
the ISA bus. In theory you could just write an "Atari DVG" driver for
the DSP and load the actual display list RAM (and ROM) into the onchip
DSP data RAM and have that run the display. If someone wanted to make
an entirely new vector game they could make a complex-curve driver and
download that to the DSP and use it instead.

-Clay
Received on Mon Mar 23 14:40:12 1998