MB012, a mother board for MC68012

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coinst...@gmail.com

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Feb 21, 2020, 11:10:56 PM2/21/20
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Thanks to Bruce Mardle I now have 2 MC68012. I have designed a low-cost pc board for it and started a homepage. https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:mb012

It is a 4"x4" 2-layer pc board with 2 I/O expansion slots. The design is based on Tiny68K and since the large 64-pin DIP is replaced with a compact PGA, the space freed up is filled with two I/O expansion slots. The MC68012 is rated at 10MHz, but I fully expect it will run OK at 12MHz. The existing Tiny68K software, including CP/M68K should run just fine on MB012.
Bill

Marc J.

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Feb 23, 2020, 10:02:34 AM2/23/20
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Hi Bill,

That's good news! Keep us informed.
I also have MC68012 from Bruce.

If anyone needs MC68000P12F (68000 16Mhz DIP64), I have some available.

Marc

--
The 68K Documentation http://marc.retronik.fr/motorola/68K

coinst...@gmail.com

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Mar 4, 2020, 9:55:46 PM3/4/20
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On Sunday, February 23, 2020 at 8:02:34 AM UTC-7, Marc J. wrote:
Received the pc board a few days ago and populate one board. It seems to run fine. CP/M68K is up and running. It passes memory diagnostic. I need to do more test, but this is very promising. Look at the picture of the assembled board here: https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:mb012
Bill

Bruce Mardle

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Mar 6, 2020, 8:33:33 AM3/6/20
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On Thursday, 5 March 2020 02:55:46 UTC, coinst...@gmail.com wrote:
> Received the pc board a few days ago and populate one board. It seems to run fine. CP/M68K is up and running. It passes memory diagnostic. I need to do more test, but this is very promising. Look at the picture of the assembled board here: https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:mb012

Looks great! Did you solder the CPLD on by hand?

coinst...@gmail.com

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Mar 6, 2020, 9:46:14 AM3/6/20
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Bruce,
Yes, the CPLD is hand soldered.

I'm waiting on 68010 PGA sockets that I'll modify slightly to accommodate 68012. Once I have the design in reasonable shape (in a week or two), I'll send you two boards, one is fully populated (but without 68012) so you can just plug in your 68012 and it should run. The 2nd board will have all the surface mount components populated and CPLD programmed. You'll need to provide the remaining parts.
Bill

Bruce Mardle

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Mar 6, 2020, 11:03:05 AM3/6/20
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Terrific!
I don't mind soldering a 68012 in; I've still got 12!
Years ago, I found a fully-populated 11x11 PGA socket, which I was planning to use for a 'NOP' tester but never got round to it.

Marc J.

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Mar 6, 2020, 2:43:58 PM3/6/20
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Le 05/03/2020 à 03:55, coinst...@gmail.com a écrit :
>
> Received the pc board a few days ago and populate one board. It seems to run fine. CP/M68K is up and running. It passes memory diagnostic. I need to do more test, but this is very promising. Look at the picture of the assembled board here: https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:mb012
> Bill
>
Nice board!

Next with 2 GB of RAM?

Bruce Mardle

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Mar 6, 2020, 3:06:58 PM3/6/20
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On Friday, 6 March 2020 19:43:58 UTC, Marc J. wrote:
> Nice board!
>
> Next with 2 GB of RAM?

:-)
As Bill pointed out, a processor running at a humble 10MHz would take a long time to process 2GB of anything.
(At 10MHz, with 4 clock cycles per word, that works out to a minimum a little over 7 minutes.)

Chris Hanson

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Mar 22, 2021, 1:50:10 AM3/22/21
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Ah, but if you run a small Unix of some sort, such as MINIX, you could
wind up finding all that RAM useful. Think of how many users you could
support!

-- Chris

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