AWCTTYPA@UIAMVS.BITNET ("David A. Lyons") (04/07/89)
>Date: Wed, 5 Apr 89 22:57:36 GMT >From: Ralph Hyre <ius3.ius.cs.cmu.edu!ralphw@PT.CS.CMU.EDU> >Subject: Re: UniDisk or SmartPort on a card? >[...] The Uni 3.5 must have all of the hardware to talk to 'bare' 3.5 >drives (it has an IWM and even a 6502 inside!) That doesn't necessarily mean that the thing has direct control over what it sends out its daisy-chain port, though. It might be limited to passing stuff through or not passing it through. >Has anyone out there actually used the code downloading facilities >to shove code into the UniDisk itself that could talk to daisy-chained >Apple 3.5s? (there is 32K of RAM in there to play with.) I suppose the >first program I write for the UniDisk will be something that sends a >listing of the ROM contents back down the smartport, so I can better >understand what's going on:-) BTW, there is only 2K of RAM in there, not 32K. I downloaded a little program to a Unidisk one time...fetched the RAM and ROM one byte at a time. Couldn't make a whole lot of sense out of it, since the CPU is _not_ just a 6502--it has extra opcodes for some dedicated hardware ports, apparently, and I have no tech info on the extra instructions. >I assume that the Smartport firmware is interruptable, reentrant, >and all that. I don't know whether it is or not. Wouldn't bet a whole lot on it myself. >BTW, How can I get the UniDisk 3.5 Tech Notes? APDA, ALPE, CIS, GEnie, an A2-Central disk-of-the-month, numerous FTP/etc archives, or send me about 3 bucks and I'll send you the TNs on 2 3.5" disks. TNs are _not_ terribly hard things to find, but they aren't going to come and find you.... > - Ralph W. Hyre, Jr. >Internet: ralphw@{ius{3,2,1}.,}cs.cmu.edu Phone:(412) CMU-BUGS >Amateur Packet Radio: N3FGW@W2XO, or c/o W3VC, CMU Radio Club, Pittsburgh, PA --David A. Lyons bitnet: awcttypa@uiamvs DAL Systems CompuServe: 72177,3233 P.O. Box 287 GEnie mail: D.LYONS2 North Liberty, IA 52317 AppleLinkPE: Dave Lyons