Path: utzoo!utgpu!watmath!isishq!f171.n221.z1.FIDONET.ORG!izot From: izot@f171.n221.z1.FIDONET.ORG (Geoffrey Welsh) Newsgroups: comp.sys.cbm Subject: Re: Another info request for old CBM computers Message-ID: <1286.23DA03BD@isishq.FIDONET.ORG> Date: 22 Jan 89 16:50:06 GMT Sender: ufgate@isishq.FIDONET.ORG (newsout1.25) Organization: FidoNet node 1:221/171 - Izot's Swamp, Kitchener ON Lines: 79 > From: jgreco@csd4.milw.wisc.edu (Joe Greco) > Message-ID: <502@csd4.milw.wisc.edu> > > In article <5745@cbmvax.UUCP> fred@cbmvax.UUCP (Fred Bowen) writes: > >The SuperPET has two built-in ACIA's, a 6551 at location $EFF0 and a 6850 > at > >location $EFF4. The 6551 is used for RS-232 I/O, the 6850 was simply a > > Open wide, Betty.... opens SuperPET. I don't see any 6850. I do see > a 6551 and support circuitry. I also don't see any 6850 in the > service / technical manuals (at least on the Super board itself). > Unless it's disguised on the 8032 motherboard, I still don't see any > 6850. Dare I contradict Fred? (Bv>) The SuperPET has EITHER a 6850 OR a 6551 in it. The early, three-board (four-switch) SuperPETs had the 6850 in them, but the late two-board (two-switch) versions had a 6551 (it requires far less support circuitry). The addresses of the ACIAs were probably changed to prevent software from writing 6850 commands to 6551 control ports. The SuperPET "system overview" (the small grey book) should give some info on the extra hardware. > Which brings up another question. Is there ANY 6502 mode support for > the 6551? None at all. Remove the combo board and you have an 8032... nothing more. The extra hardware was designed with the intention that the 6502 would completely ignore it (although some programs like PaperClip Expanded took advantage of the extra RAM). > I've managed to get some > marginally useful SuperPET terminals (6809 and 6502) but they croak > when scrolling screen at 2400 or 9600 baud. I belive that's because the ACIA was connected to the IRQ line (or none at all), and the scroll routines SEI (or don't poll the ACIA)... > What I'd like to see is device drivers, Kernal style, to support it. > With a good input buffer, a good output buffer.... (is this starting > to sound like the Plus/4?) Eventually I'd like to add an ACIA to one > of my 64's and be able to talk with my Courier 2400e at 9600 baud. Well, since I hope to have a SuperPET soon, I'll probably write something for it in 6809. There exists a SuperPET terminal called DYTTY, written by Dylan Yolles (a Toronto BBS hanger-out back when we pre-C64 dinosaurs toughed it out on RCP/M and PETBBS systems). I will also see if I can find that. On the other hand, there's not much point talking to a 2400MNP modem any faster than 4800 (which my routines, which you have seen, should achieve). I have also come up with an approach that SHOULD allow a C64 to speak 9600 and listen at 960 with the aid of RTS/CTS handshaking (which the Courier 2400e obeys, if configured to do so). I have discussed the timing aspect with the techies at Telebit Technologies and, if the USR has similar timing, the concept should work there, too. >"These aren't anybody's opinions." Do you really think so? (Bv>) =========================================================================== Internet: Geoffrey.Welsh@f171.n221.z1.fidonet.org | 66 Mooregate Crescent Usenet: watmath!isishq!izot | Suite 602 FidoNet: Geoffrey Welsh on 1:221/171 | Kitchener, Ontario PunterNet: 7/Geoffrey Welsh | N2M 5E6 CANADA BBS: (519) 742-8939 24h 7d 300/1200/2400bps | (519) 741-9553 =========================================================================== | "I don't need a disclaimer. No one pays any attention to what I say." | =========================================================================== -- Geoffrey Welsh - via FidoNet node 1:221/162 UUCP: ...!watmath!isishq!171!izot Internet: izot@f171.n221.z1.FIDONET.ORG