Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ulowell!cbmvax!daveh From: daveh@cbmvax.UUCP (Dave Haynie) Newsgroups: comp.sys.amiga Subject: Re: New Amiga Chipset Message-ID: <6562@cbmvax.UUCP> Date: 10 Apr 89 17:47:59 GMT References: Organization: Commodore Technology, West Chester, PA Lines: 50 in article , hubey@pilot.njin.net (Hubey) says: > Keywords: graphics chips > 3) As for the graphics chip set, I am not sure why HAM mode is not > available for hi-res. There aren't enough bitplanes. hi-res (~640 dots across) gives you a maximum of 4 bitplanes. HAM uses 6 bitplanes. > As a matter of fact I am not sure if the Amiga chipset is CMOS or TTL > or whatever. In any case, would it be possible to redo these chips --- > even without adding anything extra---to make them run faster (even if it > means going to another chip manufacturer who might be able to redo them in > finer--I don't know what is state-of-the-art these days 1.5 micron ??). I guess you don't do chip design for a living :-) The Amiga chips are in Commodore's 3 Micron HMOS-III process, which is a reasonably fast NMOS process; about as fast as NMOS is going to get here. Certainly one could redesign them to a new process. But the key issue here is _redesign_. Even if you were going to a smaller NMOS process (which doesn't exist), unless the chips layouts were designed to be scaleable, there would be a significant redesign time. Going to CMOS would require a complete chip redesign at the transistor level. Once you're going to all that extra effort, it's appropriate to redesign the whole thing anyway. For example, no matter how fast your process is, a chip with a 32 bit bus designed in that process could go twice as fast as a chip with a 16 bit bus. > I am (and have been for a while) wondering why even with the > additions of the MC68020 etc the Commodore chips still keep ticking at > 7.16 MHz. Is this a secret?? Maybe no one answered because no one asked? It's obvious to any hardware person. The Amiga chips, the memory they talk to, the support hardware, and everything else in the system was designed to run at 7.16MHz (a little leeway for genlocking is thrown in, but it's basically 7.16MHz). There's no magic that'll make them go significantly faster, they just weren't designed to go any faster. The 68020 processors ARE designed to run at 14.3MHz or whatever, so they can. But when they talk to the custom chips, they've got to slow down. Similarly, your car is designed to go maybe 100MPH. But when you want to get on or off, it's got to slow down at least to the speed you are designed to run at, or you're in big trouble. > mark -- Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy Amiga -- It's not just a job, it's an obsession