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101090 discussions

Epson CP/M floppy drives. Was: C64/C128 CP/M Cartridge Interest?

by fjkraan＠xs4all.nl

> So the Floppy for the PX8 is specialized for a CP/M host it's not running > CP/M itself as there is not enough ram alone to qualify. To clarify the Epson floppy drive issue, there were three products: TF-20 - Z80 based, 64k RAM, 2k ROM, boot from disk TF-15 - Z80 based, 2k RAM, 8k ROM, runs from ROM PF-10 - 6303 based, 2k RAM, 8k ROM, runs from ROM The TF-20 supported the commands used by the HX-20 and the PX-4/8 The TF-15 and PF-10 only supported the PX-4/8 commands. The TF-20 used the boot tracks of the disk to load some OS and a program which made it a serial 'file server' for the host. The OS could very well be a slimmed down version of CP/M. The HX-20 commands are file based and were issued mainly from Basic. The Basic extension is also on the boot disk. The PX-4/8 commands are sector based and issued from CP/M. All devices used the same protocol, epspd and baud rate. The same protocol was used internally in the HX-20/PX-8 between the various processors. The HX-20/PX-8 external video device also used it. The TF-15 and PF-10 are both ROM based. The TF-15 used the same housing as the TF-20. As this resembled the QX-10 computer, the origin of the TF-15/20 product was probably to provide two extra floppies for this computer. For those interested http://www.xs4all.nl/~fjkraan/comp/tf20/ contains some info on epsp and the TF-20 boot disk. Fred Jan

15 years, 5 months

Computer History Entertainment

by david＠classiccomputing.com

On Dec 27, 2010, at 1:00 PM, cctalk-request at classiccmp.org wrote: > Sounds interesting - on which classic computers do these "shows" run? > > > Regards > > Rod Smallwood Hi Rod, They are podcasts, so you have to do like when you were a kid. You know, you sit in front of the TV watching "Scooby Doo" with your stuffed Scooby, or like that. So, you tinker around with your old computers, etc. while listening. ; ) Well, unless you're driving. Best, David Greelish, Computer Historian Classic Computing The Home of Computer History Nostalgia http://www.classiccomputing.com Classic Computing Blog Classic Computing Show video podcast "Stan Veit's History of the Personal Computer" audiobook podcast Retro Computing Roundtable podcast Historical Computer Society Classic Computing Expo 1.0 - planning for sometime late 2011!

15 years, 5 months

Computer History Entertainment

by david＠classiccomputing.com

On Dec 27, 2010, at 1:00 PM, cctalk-request at classiccmp.org wrote: > I just got around to listening today. That was marvelous, thanks very much. > Merry Christmas to all, > Charlie C. Thanks Charlie! Best, David Greelish, Computer Historian Classic Computing The Home of Computer History Nostalgia http://www.classiccomputing.com Classic Computing Blog Classic Computing Show video podcast "Stan Veit's History of the Personal Computer" audiobook podcast Retro Computing Roundtable podcast Historical Computer Society Classic Computing Expo 1.0 - planning for sometime late 2011!

15 years, 5 months

Computer History Entertainment

by david＠classiccomputing.com

Hi everyone, If you have never checked out any of the shows that I produce, please consider checking one or more out over the holidays. I just posted the new Retro Computing Roundtable podcast today. Find it here - http://bit.ly/iazQ2S with links to the others at the top of the page. There is also - "Stan Veit's History of the Personal Computer" audiobook podcast & the Classic Computing Show video podcast. I'm like the Leo Laporte of computer history podcasts! Well, OK, so I'm not as professional, and I don't have the years of radio and television experience, nor the equipment, or the money . . . OK, OK, I stink compared to Leo, I'm nothing like him! ; ) They're good shows. Have a great holiday season. Best, David Greelish, Computer Historian Classic Computing The Home of Computer History Nostalgia http://www.classiccomputing.com Classic Computing Blog Classic Computing Show video podcast "Stan Veit's History of the Personal Computer" audiobook podcast Retro Computing Roundtable podcast Historical Computer Society Classic Computing Expo 1.0 - planning for sometime late 2011!

15 years, 5 months

Undocumented 8080 instructions?

by eric＠brouhaha.com

Does anyone have information on undocumented 8080 instructions? There's plenty of information out there about undocumented Z-80 and 8085 instructions, but I haven't found anything on the 8080. Some of the non-Intel 8080 and 8080-compatible parts were independent designs, rather than licensed second-sources using Intel-provided masks, so those might have different behavior for the undocumented opcodes. Thanks, Eric

15 years, 5 months

C64-C128 CP-M Cartridge Interest

by dm561＠torfree.net

------------Original Message: Date: Fri, 24 Dec 2010 18:19:41 -0800 (PST) From: Fred Cisin <cisin at xenosoft.com> Subject: Re: C64-C128 CP-M Cartridge Interest <snippage> It's too bad that nobody brought up CP/M on the Kyoceras (Radio Shack model 100, Nec 8200, etc). THAT would have been a project. Or on the Epson RC20! ------------Reply: As you've read elsewhere Allison did indeed do just that, and some folks in the Club100 group have also (sporadically) been working on this for a while. mike

15 years, 5 months

Looking for EPROM 2708 help

by trebor77＠execpc.com

Is there anyone out there that can BURN a 2708 EPROM for me. My Data I/O System-19 W/UNIPAK is DAS Kaput. It will not burn me a good prom. Not Sure why though. My Fault ???? I am trying to add some code to Dave Dunfields Monitor to find out why the 2708 that Andrew burnt is malfunctioning on my N*. I have tried to add several lines of code but the resulting Prom just doesn't perform the way the Andrew Prom does. I am using a SOL-20 System/Bus Probe that will Single Step the N* CPU so I can then track the code and its execution. I can see the results of the OUT 3 & 2 Instructions but not the IN 2. I am going to add jumpers to the Probe to display "Data In" as well as the existing "Data Out" and that might help. I have at least 5 2708's and can mail one out then I can sent the Code as an attachment. ALSO is there anyone out there using Dave's Monitor Mapped at "0000" that would be willing to test the 2708 that I have; that works somewhat; that way I could determine if the Fault is in the N* or in the Code itself. Since I can't burn a New Prom I am up the creek without a Paddle so to speak. TIA Bob in Wisconsin

15 years, 5 months

C64-C128 CP-M Cartridge Interest

by lynchaj＠yahoo.com

C64-C128 CP-M Cartridge Interest Jim Brain brain at jbrain.com <mailto:cctalk%40classiccmp.org?Subject=Re%3A%20C64-C128%20CP-M%20Cartridge% 20Interest&In-Reply-To=%3C4D1631AE.3080201%40jbrain.com%3E> Sat Dec 25 12:02:22 CST 2010 [snip] Yep. No offense to the list participants, but I gave up on selling kits. Given the hobbyist nature of my work, kits required too much of my limited hobbyist time. Given the assembled nature of the unit, I can use extremely large density devices with no issues. [snip] > I am not familiar with the SuperCPU but based on quick web search it appears > to be roughly Eurocard sized. Good luck with your project. It is rather large as well. Though, with today's integration options, it too could be constructed in the smaller space of a CBM game cartridge. In fact, it would have to be to bring the cost to something reasonably. People was apprehensive about a $300.00 20MHz accelerator in the late '90s, there's no way they'd pay that much now. Jim -----REPLY----- Hi Jim, I can certainly relate. For the N8VEM project, I have never offered kits and probably won't ever. All I offer is the PCB, schematics, PCB layout, and a parts list. I encourage people to make their own boards and only rarely supply some hard to get parts on an exception only basis. Commonly available parts are entirely up to the builder to source and supply. If you have the pre-made PCB and a parts list what is the difference between that and a kit? You get the PCB and then order the parts from Jameco. Dump all the parts on your workbench and call it a kit! Read the schematic and follow the PCB layout. It doesn't get much easier than that! Making kits is going to eat up all of your time and money with little or no return and huge frustration. It just isn't practical IMO and can scarcely be called "homebrew computing" when all the parts arrive in one bag. Admittedly, using a pre-made PCB is a bit of a stretch too but it is a reasonable compromise to get more hobbyists involved. I think the PCB is the biggest barrier to entry (perf board wire wrap, point to point soldering, or pre-made PCBs) for new hobbyists to homebrew computing. I certainly wish you the best of luck with your project if you decide to do it. There doesn't seem to be a huge groundswell of interest here but it is hard to make any reliable judgement based on comments on CCTALK though. Maybe spin up a few prototype boards and sprinkle them to some experienced builders and see what sort of reaction it generates would be a good market research? That's what I do. Thanks and have a nice day! Andrew Lynch PS, I just got word that one of the N8VEM builder who is lead on the S-100 68K CPU board has completed assembly of the first unit. No test yet but things are certainly looking good. I am very excited about the S-100 68K CPU board. Hopefully build and test goes OK and we can release that board before too long.

15 years, 5 months

C64-C128 CP-M Cartridge Interest

by ken＠seefried.com

FWIW... From: allison <ajp166 at verizon.net> > Minimal system: > > 8080, 8085, NsC800, Z80, or Z180 cpu. The prefered CPU is z80 as > it's easy to interface and there are some CP/M apps that require it. > > 64K ram, (technically cp/m runs in 20k or more but useful apps are > minimally 48K) > > Boot rom(eprom/flash) that maps out of the 0000h startup address > > Mass storage, this can be floppy, CF, SD, Or some form of rom/ram to > look like disk. > > User IO, typically a serial line for a terminal can be a memory mapped video > and keyboard or similar. > For my high school senior project, I designed and built essentially this, significantly over 20 years ago. Z80, 64k RAM (4 x 16Kx8), serial port, simple relocating boot ROM, relevant CBIOS, floppy. I had a TRS-80 4P running Montezuma CP/M (thanks, Dad) to write code on and a random EPROM writer to program 2764s. Got it to boot CP/M in a semester, working an hour or more daily, 5 days a week. I'd also generally figured out how to interface, for local reasons, to STD-Bus for expansion, but never actually implimented it. Had an Intel bubble memory dev kit (128k), but also never got around to it. Went to college, had Vaxen, 3B2s and early Suns with Unix and C, with a sprinkle of Pascal, Modula-2 & Ada followed by Symbolics and Xerox AI machines. And I relized how much more interested I was in solving big problems than figuring out what problems I could fit into tiny computers, and never looked back. Maybe I'll see if I can find the remaining bits and notes in the basement one day. Point being, it's an imminently doable project, of variable utility these days, and there's a ton of existing work that can be leveraged. KJ

15 years, 5 months

ISO Corvus transporter card with piggyback EPROM

by aek＠bitsavers.org

Not much of a chance, but I thought I'd try. Corvus released a special version of the transporter firmware that went in a piggyback EPROM on the microcontroller. I've been looking for the code for a LONG time. It is mostly useful for packet sniffing.

15 years, 5 months

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