Subject: Re: [stella] Midified VCS... From: Chris Wilkson <ecwilkso@xxxxxxx> Date: Wed, 21 Nov 2001 11:23:43 -0500 (EST) |
On Wed, 21 Nov 2001, Oliver Achten wrote: > Wasn't it said to have about 5000 gates? Can't imagine that it has nearly > three times as many gates as the 6502 (considering the simplicity of the I've heard both numbers. And I've guessed about 1000-2000 transistors. But I haven't gotten far enough into it to know. I can say that my numbers are WAY too low. > design). You yould also simplyfy it by abadoning the old CVBS logic in favour of > having an rgb output (which would be much simpler). Wrong. The video inside the chip is just a 7-bit number. The only real CVBS thing there is the chroma delay, which is just a tapped delay line. All the analog voltage levels are created off-chip, on the motherboard. To represent 128 colors with RGB, you still need 7 bits, and then how do you split them? You'd need 9 bits to split evenly between the 3 colors. And even then, you may not be able to reproduce the colors in the original palette. Maybe, but I don't think it's worth the effort right now. > Again, what kind of logic do they use? To what level of abstraction are the > schematics drawn? The chip is NMOS. The schematics are gate level, but there are random single transistors floating around as well. > I hope you'll be succesful and that you will be in the right mood to write a > nice documentation about it.... ;-) Yes, I'm writing my thesis on this chip. I'll reprouce the chip in some form, and the paper will be *very* detailed, and *very* complete. > Are there any chances for a person not living in the states to have the > schematics? As mentioned here several times, you should contact Curt Vendel. I don't have his contact info though.... -Chris ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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