editing the miniman uzebox for 256 levels of gray

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huze11
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editing the miniman uzebox for 256 levels of gray

Post by huze11 »

so the minimal uzebox offers a circuit to allow the normal uzebox games to run , so it distributes the 3 bits of the 3bit colors and the 2 bits of the 2bit color on the DAC .
but what if someone needs an 8bit grayscale quality out of the uzebox ? instead of the rgb games ?
can someone do a good calculation for a decent resistor ladder for this ? i dont think it would be very complicated

then in code you can write programs for this , it's just that the representation of color would change
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uze6666
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Re: editing the miniman uzebox for 256 levels of gray

Post by uze6666 »

Check out this post by Steve Chamberlain: http://uzebox.org/forums/viewtopic.php?t=343. There's also a schematic pdf here.
huze11
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Re: editing the miniman uzebox for 256 levels of gray

Post by huze11 »

i did check that before posting . that circuit does not provide 8bit grayscale quality . since it has repeating shades . like i already said that circuit outputs bits for R G and B then tries to pack them up in a 2-3-3 DAC with the sync signals . i did test that circuit btw , and it has repeating shades of gray . you can calculate the odds i think
since when you reverse the colors in both the 3bit colors you would get the same level of gray . while the 8bit grayscale circuit works similarly to an R2R resistor ladder but with a 0.3v buttom when sync is high and a 1v top . and a 0v when sync is low .
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uze6666
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Re: editing the miniman uzebox for 256 levels of gray

Post by uze6666 »

If your get a better design that doesn't need kernel change, let me know and I'll post your design.
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