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commodorejohn
August 29th, 2014, 09:49 PM
Was there ever much in the way of a standard for 68k-based homebrew systems? I know there was the VME bus, but I get the impression that that was more of a business/embedded thing overall, and similarly I know of some individual 68k-based desktop computers from the peak years of the homebrew/S-100 era, but they were mostly business systems.

The reason I ask is that I've gotten a major hankering to do some low-level 68k hacking on something close to bare metal, but the 68k systems I have on hand don't have a simple, well-documented way to get control of the system on something equivalent to the BIOS level that any fool can throw together a booter floppy for on an IBM PC-compatible. (Well, the Amiga comes fairly close, but I don't have a spare at the moment and don't want to mess up my 1200!) Granted, I could just dig around in the system-specific source for BSD/hp300 until I figure out how to get a homebrew system/monitor up and running on my HP 9000/425t (which is what I'd planned to do with it anyway,) but I'm craving instant gratification, here...

Was there ever such a thing? In particular, was there ever a decent homebrew system based on one of the fully 32-bit 68k variants?

Jack.
August 30th, 2014, 01:35 AM
I don't know about vintage homebrew but someone here (http://www.ist-schlau.de/) built a computer around the 68k, so they got to have some documentation about writing software aswell.
This guy (http://mc68k.blogspot.pt/) also built his own 68k homebrew computer and i guess you can download his toolchain there.

daver2
August 30th, 2014, 02:08 AM
There was CP/M 68K - you can't get any more 'standard' than that.

You will find the sources (yes, the sources) at "http://www.cpm.z80.de/source.html". You will also find the sources there (according to the webpage text) for a BIOS.

Don't expect too much from the disk images though - I suspect they will require a lot of work to get them to run... There were a number of computers 'back in the day' that used CP/M-68K (The Sage was one I remember) so there may be complete disk images for (say) a Sage that you can find on the web and 'butcher' for your use (i.e. you may be able to extract the executable code from your disks and write your own BIOS to go with them rather than making a 'clone' of the hardware for a Sage).

I was looking to do a similar thing for CP/M-Z8K for the Zilog Z8000 - but so many things get in the way of so many other things until I retire!

Dave

cr1901
August 30th, 2014, 04:25 AM
I STRONGLY suggest you buy a copy of The 68000 Microprocessor (http://www.amazon.com/The-68000-Microprocessor-5th-Edition/dp/0130195618) textbook by James L. Antonakos. One of the final chapters details how to create your own minimal-component but fully functional 68k system with ROM monitor and serial port. It also uses some of Motorola's I/O chips (the UART obviously being one :P).

Al Kossow
August 30th, 2014, 06:47 AM
Was there ever such a thing? In particular, was there ever a decent homebrew system based on one of the fully 32-bit 68k variants?

Ingo Cyliax built a 68030 SBC with ISA slots at the Indiana University and published articles in Circuit Cellar

#86 September 1997, p. 62, MicroSeries MC68030 Workstation, Part 1: The Hardware
#87 October 1997, p. 66, MicroSeries MC68030 Workstation, Part 2: The Boot PROM Monitor & Device Drivers
#88 November 1997, p. 66, MicroSeries MC68030 Workstation, Part 3: Cross-Development Environment and Downloading

I bought a couple of bare boards from him back in the day, I need to get them scanned and
the docs put on line (I thought I had done that already)

g4ugm
August 30th, 2014, 07:08 AM
I don't think the 68000 homebrew systems ever achieved the level of standardized of the SWTPC SS50 based systems. There were a number of designs produced, but really you could buy an Amiga, Mac or Atari that was ready to go. I have an Atari STE and TT030i and its documented down to the BIOS levels....

Al Kossow
August 30th, 2014, 07:23 AM
I have an Atari STE and TT030i and its documented down to the BIOS levels....

MESS has the Macintosh up through the 030 machines documented adequately that you could swap out the toolbox roms
with your own monitor talking through the SCC. You'd probably want to use some removable media SCSI though rather
than having to mess with writing your own SWIM driver for 1.4Mb MFM floppy support. You'd also want to pick a model,
like an LC, which didn't require software setting up the memory controller or video (not that you'd need the video at first).

commodorejohn
September 4th, 2014, 11:56 AM
Here's an interesting one: an '030-based SBC with an ISA bus and SIMM memory. (No DMA, though.) Supposedly it runs Minix. The BOM is mostly standard parts, too:

http://www.retro.co.za/68000/ftp.cs.indiana.edu/pub/goo/mc68030/

Al Kossow
September 4th, 2014, 01:05 PM
Here's an interesting one: an '030-based SBC with an ISA bus and SIMM memory. (No DMA, though.) Supposedly it runs Minix. The BOM is mostly standard parts, too:

http://www.retro.co.za/68000/ftp.cs.indiana.edu/pub/goo/mc68030/

* Copyright 1993 Caleb Hess and Ingo Cyliax, Indiana University

That's the one I was talking about

commodorejohn
September 4th, 2014, 01:07 PM
Ooh, 4-layer PCB though. Wonder how much that'd run me.

glitch
September 4th, 2014, 01:11 PM
The guys at s100computers.com put together a 68K S-100 board based on the Alan D. Wilcox 68K book:

Board: http://www.s100computers.com/My%20System%20Pages/68000%20Board/68K%20CPU%20Board.htm

Book: http://www.amazon.com/68000-Microcomputer-Systems-Designing-Troubleshooting/dp/0138113998/ref=la_B001HPZNVI_1_2?s=books&ie=UTF8&qid=1409865074&sr=1-2

EDIT: Also, it appears there is/was a MIKBUG like debugger for the 68K: http://www.retro.co.za/68000/humbug.html

smp
September 4th, 2014, 02:27 PM
The guys at s100computers.com put together a 68K S-100 board based on the Alan D. Wilcox 68K book:


Well, Glitch beat me to it. I'm glad I read all the way through the thread to the end to see it, so I did not end up embarrassing myself with a redundant post. But, I, too, was thinking right away about the folks over at www.s100computers.com. I can't tell you how many times that I have been tempted to try that project myself.

smp