Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!zephyr.ens.tek.com!tektronix!psueea!parsely!agora!billsey From: billsey@agora.UUCP (Bill Seymour) Newsgroups: comp.sys.amiga.tech Subject: Re: speeding up the amiga and hardware hacking Message-ID: <1803@agora.UUCP> Date: 13 Jan 90 21:13:24 GMT References: <697@tau.sm.luth.se> <140.filbo@gorn.santa-cruz.ca.us> Reply-To: billsey@.UUCP (Bill Seymour) Organization: Organization? You've got to be kidding! Lines: 57 In article <140.filbo@gorn.santa-cruz.ca.us: filbo@gorn.santa-cruz.ca.us (Bela Lubkin) writes: :In article <697@tau.sm.luth.se: Karl-Gunnar Hultland writes: ::contact and a switch to XCLK enable and thus get a FASTER amiga. ::If this works it would give faster custom chips too, and I'd like ::that very much. : :I've asked about this before (not here) and never gotten a good answer. :I'd like to hear from the real hardware gurus on this. Obviously many :components of the system will not stand up to being sped significantly; :yet, as with most electronics, you could probably get another 20-30% out :of it. That's right.You get the faster speed. I've got it hooked to my 2000 via a switch attached to a CMI VI-200 (The NES Video prototyping card wasn't available yet then...) Everything I've tried to run works just fine, and the speed increses are exactly what you'd expect. :There is a MAJOR side-effect: you speed up the video timing. This means :that your video output will not work on anything but a specialized :monitor or a multisync (and then only if it covers the right range of :scan rates). This also means that the pixels and lines are closer :together -- you might be able to increase the screen size (and keep the :scan rates down), but I suspect there are too many hard limits in the :video chips to do too much along those lines. This is actually not as much of a problem as you think. After all, a multisync monitor fixes it. OR you could change the pot on your monitor that adjusts the horizontal roll... Where the *major* problems show up is in accessing the 8520s. You will not be able to use the serial port or the floppy drives with any degree of success. I suppose you could rewrite serial.device to take into account the faster clock and trackdisk.device for the floppies though... :It would be very easy to test the idea. Make an external clock box and :go for it. I think you can actually get variable-speed crystals if you :want to spend a significant amount of money; you could experiment with a :large continuous range of speeds. I have no problems hardware wise at 8MHz. Even my Processor Accelerator worked! (That made me 16MHz...) But the floppy and serial troubles were enough to leave the switch in the 7M position. :-) :There's enough chance of damaging hardware to say: BE CAREFUL! : :* Newgroup vote in progress: comp.sys.amiga.hardware; see call for votes in * :* news.announce.newgroups. Unambiguous YES/NO votes to trent@ucscb.ucsc.edu * :-- :Bela Lubkin * * // filbo@gorn.santa-cruz.ca.us CI$: 73047,1112 (slow) : @ * * // belal@sco.com ..ucbvax!ucscc!{gorn!filbo,sco!belal} :R Pentomino * \X/ Filbo @ Pyrzqxgl +408-476-4633 and XBBS +408-476-4945 -- -Bill Seymour ...tektronix!reed!percival!agora!billsey ============================================================================= Bejed, Inc. NES, Inc. Northwest Amiga Group At Home Sometimes (503) 281-8153 (503) 246-9311 (503) 656-7393 BBS (503) 640-0842