Path: utzoo!utgpu!water!watmath!clyde!bellcore!rutgers!mailrus!ames!oliveb!amiga!cbmvax!daveh From: daveh@cbmvax.UUCP (Dave Haynie) Newsgroups: comp.sys.amiga Subject: Re: 68020/68881 board Message-ID: <4480@cbmvax.UUCP> Date: 11 Aug 88 19:19:08 GMT References: <11655@cisunx.UUCP> Organization: Commodore Technology, West Chester, PA Lines: 44 in article <11655@cisunx.UUCP>, ejkst@cisunx.UUCP (Eric J. Kennedy) says: > In article <4447@cbmvax.UUCP> daveh@cbmvax.UUCP (Dave Haynie) writes: >>> 1) How compatible is it with current software? >>Very, like probably 99.9%. What's likely to die? Only thing that occurs to me >>is the R-C type dongle, as used with X-CAD. These things are very sensitive >>to CPU speed, generally depending on CPU dependent timing loops. Under V1.3, >>the 68881 interface will be supported if they did it right. > If my Superbase Professional dongle dies, (same company) I'm going to > be SCREAMING mad!! Actually, isn't X-CAD from the folks who make Aquisition? I know both are British companies, but I didn't think they were the same. The Dongle Snooper I use tells me that the SuperBase Professional dongle I have here is of the resistor-on-a-pot-line variety (13k-16k). Providing that's correct, this dongle should be immune to CPU speed variations. The X-CAD dongle we tried here was identified as the R-C constant varitey. That's real bad news, and it didn't surprise me that the darn thing failed. The theory behind is that a capacitor is charged and discharged under program control, with one input line to sense the capacitor's charge. While that's a purely digital sensing, what they do is start a timer and read that port line until a "1" is sensed. Same thing can be done with a discharge of the cap. The problem is that, unless the programmer was smart enough to use a timer, the count produced is just going to be a CPU based count, and that's 100% dependent on CPU speed. And I should mention that Commodore-Amiga definitely doesn't support this kind of dongle, since Commodore-Amiga doesn't support anything that's dependent on a fixed CPU speed. > Damn ##$$@^%$! dongles I'll agree with that in any case. > ------------ > Eric Kennedy > ejkst@cisunx.UUCP -- Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests" {ihnp4|uunet|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy "I can't relax, 'cause I'm a Boinger!"