Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!julius.cs.uiuc.edu!psuvax1!rutgers!mcnc!ncsuvx!news From: kdarling@hobbes.ncsu.edu (Kevin Darling) Newsgroups: comp.sys.m6809 Subject: Re: 6309 Message-ID: <1990Dec15.112436.7788@ncsuvx.ncsu.edu> Date: 15 Dec 90 11:24:36 GMT References: <00940D61.63CAC900@rigel.efd.lth.se> <1990Dec12.071103.7358@ncsuvx.ncsu.edu> Sender: news@ncsuvx.ncsu.edu (USENET News System) Organization: NCSU Computing Center Lines: 22 Because I've gotten a bunch of mail inquiries about using a Hitachi 63C09E (3 Mhz version of the 6809E) I thought I'd better post this in general: Putting in a higher speed-rated chip will _not_ speed up your CoCo. At most, this chip will draw less power, and run much cooler. But the CoCo is designed to run at certain speeds (the max of which is 2Mhz), and cannot be speeded up because of timing requirements for shared video memory access, etc. (Umm, it _is_ possible to design a circuit to speed up the cpu during internal-only calculations.... Bob Puppo did such a circuit, but it's rather complicated for the only about 20% speed increase you can get). But no, just dropping in a 3Mhz rated cpu won't speed you up, any more than putting in 50ns DRAMs would. This is very akin to putting "200mph" tires on a 100mph top speed car... you have more safety margin, but they WON'T make the car go faster. You only got more expensive tires, is all ;-). The 6309 we ran at 3-5Mhz was obviously not in a CoCo... but in a simple controller board without any video, etc. - kevin