>clay has my wico generator, don't know if he ever traced the circuit
>out or not. from memory, it was a lot more complicated than I thought
>it would be. A microcrontroller and a couple of DACs would do everything
>that box did.
Yeah, I took a look at the Wico color one with the intent to trace it out,
but it's too damn complicated.
I was thinking an OK design might just be something like:
Two big EPROMs in parallel (16 bits wide), or one bit 16 bit wide EPROM.
One 10 to 12 bit DAC. A couple of sample and holds feeding the X/Y output
circuitry. Two 4040 counters and a clock oscillator.
The EPROM bits are used as:
DAC Data (12 bits)
RGB (on or off for each color) (3 bits)
Done (1 bit)
The EPROMs just hold X,Y,color data at each location. Odd addresses are the
Y axis, even addresses are the X axis. Each sample and hold is updated
based on the A0 line and goes to the X/Y outputs.
A PC vector-drawing program (like my old Sega vector editor) would just
output a list of XY coordinates and colors. Essentially just a sequential
list of pixels. The 4040's are cascaded to make a big free-running
up-counter. The up counter connects to the address lines of the EPROMs.
The top address lines on the EPROMs go to a rotary switch or something to
select one of several "pictures". The 4040's free run, sequentially
addressing all the data in the EPROM until they hit the "done" bit which
causes them to reset and start counting again.
The frame rate would be variable depending on the drawing complexity, but
the PC could add a lot of "black" drawing at the end of the display list.
If you used the top three lines of the EPROM address bus to select the image
you'd get 8 64K word "programs". That would be 32K "pixels" per program, or
about 32 "full screen" lines at 1024x1024 resolution. (So a convergence
grid would probably be the most complex image, maybe 16x16 full-screen
lines.)
Anyway, it'd be relatively simple to make... (Although a little
microcontroller could just as easily run the DACs too, I just liked being
able to use the PC to draw stuff easily.)
-Clay
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Received on Thu Mar 30 20:32:43 2000
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