This is totally cool. Great if we can run flickernoise on the nanonote and some other audio applications, then we have a small performance system :)
Jon On Thu, Apr 28, 2011 at 9:37 AM, Werner Almesberger <[email protected]> wrote: > David Kuehling wrote: >> Werner, you're a genious. Zooming into the image, I can't see see any >> dithering. How did you manage that many colors? > > Here's the circuit: > http://projects.qi-hardware.com/schhist/ubb-vga/pdf_ubb-vga.pdf > > Each color channel gets a signal level that has about 2/3 from the > respective binary color channel plus a shared binary luminance value > that contributes 1/3 of the level. > > The board isn't very difficult to make. If you look at > http://downloads.qi-hardware.com/people/werner/ubb/vga/ubb-vga2-prototype.jpg > R5-R7 are soldered SMT-style to the UBB contacts. I placed R8-R10 > directly underneat the board, soldered in the same way. (They just > need a bit more heat, because they're soldered to the ground plane.) > > R3 crosses from "blue" all the way to Y. I then soldered R1 and R2 > to the long leg of R3. Last but not least, R4 is soldered SMT-style > too. > > To minimize mechanical strain during assembly, I combined the three > resistor triplets by twisting their VGA-side wires together. Then I > soldered them to UBB and finally added solder on the VGA side, too. > I did this last so that I would still have some wiggle room when > working on the UBB side. > >> You might want to have a look at the color lookup code used in the >> allegro game library (alleg.sf.net). They used a 2^5 x 2^5 x 2^5 lookup >> table for RGB -> palette color mapping, > > Ah, very good. Yes, that sounds useful. Right now, I iterate > through all 16 possible values and compute the (squared) distance > within the RGB cube. It doesn't really take all that much time, > but it can't hurt to make this more efficient. > >> Plus you already have code for loading files into bitmaps (bmp, tga or >> pcx). > > Oh, implementing the few simple things I need for my tests probably > takes less time than even matching APIs and sorting out library > dependencies would :-) Besides, I had the PPM loader already. > > - Werner > > _______________________________________________ > Qi Hardware Discussion List > Mail to list (members only): [email protected] > Subscribe or Unsubscribe: > http://lists.en.qi-hardware.com/mailman/listinfo/discussion > -- Jon Phillips http://rejon.org/ | http://fabricatorz.com/ chat/skype: kidproto | irc: rejon +1.415.830.3884 (global) | +1-510-499-0894 (sf) +86-187-1003-9974 (beijing) _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
