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 Motorola 68000 information for newbies 
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Joined: Mon Feb 03, 2020 4:08 am
Posts: 6
Location: Planet Earth, FL, USA
Over the decades, I always wanted to build some sort of 68K based machine. I've done several 65C02 machines over the past 30+ years and continue to as I've always enjoyed the 6502 and it's later CMOS versions. Back in the 80's I actually purchased a 68000 CPU in CDIP when I was in CA for work... I visited Jameco and found that along with a few other chips to buy. Granted, I still have the 68K, but it's somewhere in the attic, so it's not going to be accessible anytime soon (South Florida heat).

As most would know, the 68K has a flat memory model (vs segmented ala Intel) and is also Big-Endian, unlike Intel and also the 6502 which are Small-Endian. So moving to the 68K can present some additional challenges, when coming from the older 8-bit CPUs and even earlier Intel 16-bit CPUs.

As I spend a fair amount of time researching for information, I stumbled across a series of PDF charts from Wright State University. It was from a course offered some decades ago most likely, but I've found them to be quite informative and in some cases, easier to get your head around working with the 68K, both hardware and software. I'm simply providing the links to these PDFs. If anyone has a desire to learn more or possibly start a project with the 68K, I would recommend them along with the usual Motorola (and later NXP) documentation.

I do plan on designing and building a 68K Pocket SBC based on the ExpressPCB Miniboard format (2.5" x 3.8" 4-layer PCB), but it's going to take some time... as I'm fairly busy with other projects in my newfound retirement. In any case, here's the links to the referenced presentations. I hope someone else find these to be of value as well.

http://research.cs.tamu.edu/prism/lectu ... bsd_l1.pdf
http://research.cs.tamu.edu/prism/lectu ... bsd_l2.pdf
http://research.cs.tamu.edu/prism/lectu ... bsd_l3.pdf
http://research.cs.tamu.edu/prism/lectu ... bsd_l4.pdf
http://research.cs.tamu.edu/prism/lectu ... bsd_l5.pdf
http://research.cs.tamu.edu/prism/lectu ... bsd_l6.pdf
http://research.cs.tamu.edu/prism/lectu ... bsd_l7.pdf
http://research.cs.tamu.edu/prism/lectu ... bsd_l8.pdf
http://research.cs.tamu.edu/prism/lectu ... bsd_l9.pdf
http://research.cs.tamu.edu/prism/lectu ... sd_l10.pdf
http://research.cs.tamu.edu/prism/lectu ... sd_l11.pdf
http://research.cs.tamu.edu/prism/lectu ... sd_l12.pdf
http://research.cs.tamu.edu/prism/lectu ... sd_l13.pdf
http://research.cs.tamu.edu/prism/lectu ... sd_l14.pdf
http://research.cs.tamu.edu/prism/lectu ... sd_l15.pdf
http://research.cs.tamu.edu/prism/lectu ... sd_l16.pdf

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Regards, KM
https://github.com/floobydust


Tue Aug 25, 2020 4:07 am

Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1647
Nice find!


Tue Aug 25, 2020 6:45 am
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Joined: Mon Feb 03, 2020 4:08 am
Posts: 6
Location: Planet Earth, FL, USA
Thanks Ed,

As I'm continuing to learn more about the 68K, I've downloaded a fair amount of info... datasheets and the usual Motorola and NXP documentation. I just found a really large amount of downloadable material at one website. It includes Motorola Datasheets, Motorola Application Notes, a list of Articles and some hardware Board Projects plus the Vu68K hardware and Vu68K VuBUG monitor code from Byte magazine 1984. For anyone interested (in the 68K), this link should be quite valuable:

http://marc.retronik.fr/motorola/68K/68000.html

_________________
Regards, KM
https://github.com/floobydust


Mon Aug 31, 2020 1:54 am

Joined: Thu Oct 21, 2021 5:22 pm
Posts: 12
Unfortunately, it looks like the PDF charts from Wright State University are not available. Server not found. Has anyone dragged it all away to themselves? Confess and share .. :roll:
But I intend to build the Vu68k SBC. I think this is a good starting point for a beginner like me.


Fri Oct 22, 2021 11:44 am

Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1647
There seem to be copies of those PDFs here:
https://people.engr.tamu.edu/rgutier/le ... bsd_l1.pdf
...
https://people.engr.tamu.edu/rgutier/le ... bsd_l9.pdf
https://people.engr.tamu.edu/rgutier/le ... sd_l10.pdf
...
https://people.engr.tamu.edu/rgutier/le ... sd_l16.pdf

(and at the internet archive too: https://web.archive.org/web/*/https://p ... res/mbsd/*)


Fri Oct 22, 2021 12:08 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 273
Wireless world (UK) oct 1985 had a 68000 board design.
https://worldradiohistory.com/Wireless_ ... gazine.htm


Fri Oct 22, 2021 11:23 pm

Joined: Thu Oct 21, 2021 5:22 pm
Posts: 12
I tried to look. The attempt failed. Nothing happens for a minute, and then a message appears: - Connection timed out.
I tried looking for this magazine elsewhere:
https://www.americanradiohistory.com/Ar ... 985-10.pdf
https://www.americanradiohistory.com/Ar ... 985-11.pdf
The result is the same.
If anyone has these files available, could you please send them to me by email? Or in some other way...
This is two issues of Wireless-World: oct. and nov. 1985.


Sat Oct 23, 2021 4:54 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 273
It works on the American side of the Alantic ocean.
I can't get this link to work over here. It may work on your side of the world.
http://www.retro.co.za/68000/
I could email the PDF's but I need to hear BigEd's thoughts on it first.
Ben.


Sat Oct 23, 2021 5:30 am

Joined: Thu Oct 21, 2021 5:22 pm
Posts: 12
OK, let it be at BigEd's discretion.
http://www.retro.co.za/68000/ doesn't work either. I discovered this a long time ago when I googled for some information.
I wonder what these links have in common? Is it all on the same server?


Sat Oct 23, 2021 6:38 am

Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1647
Best not to attach anything here which might cause the forum admins a problem. But by private email, do what you like!

To have a quick look at something which might be easier to access from the US, or might need a different browser, I often use
https://www.browserling.com/
(but there's no way to save anything)

Another possibility is to browse the Internet Archive's Wayback Machine - or, indeed, to ask it to fetch a copy of something, so you can then see the copy. See http://web.archive.org/save

Specifically, we do find
http://web.archive.org/web/202108170354 ... .za/68000/
but it seems the wordradiohistory site is not visible.

Any VPN or proxy might help, if the problem is a geoblock.


Sat Oct 23, 2021 7:28 am

Joined: Thu Oct 21, 2021 5:22 pm
Posts: 12
The Wayback Machine is working as it should. Thanks BigEd. You made my evening.
For example, here
http://web.archive.org/web/202108170341 ... k/68k.html
I found a simple project with all the necessary files. Here everything is mostly clear to me. Many bugs, but still interesting.

In my opinion, the book by Peter A. Stark "68000 Hardware Manual" is very useful for every novice hobbyist who has decided to make the M68k SBC on his own.
http://web.archive.org/web/201908080957 ... rdw68k.htm


Sat Oct 23, 2021 2:37 pm
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