68EC000 SBC - 10*10cm pcb

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Ola Hollum

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Feb 29, 2016, 4:57:34 PM2/29/16
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HI,
I am trying to design a low cost SBC with the 68EC000.
Low cost means small 2-sided PCB, must fit 10*10 (price :) )
Also, surface mounting seems difficult, and should probably be avoided.

I may be able to program GALS, so 16V8..22V10 are potential part of the design.

A i/o bus should be included, but main memory should be on the cpu board to keep the bus small. Also, 1-2MB ram is probably sufficient, as I will settle for terminal interface. But some permanent storage must be present, maybe SD-card? Never tried those, but ebay have moduls which could be used.

Any suggestions?

Ola

Marcopolo

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Mar 1, 2016, 3:00:49 AM3/1/16
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Le 29/02/2016 22:57, Ola Hollum a écrit :
> HI,
> But some permanent storage must be present, maybe SD-card? Never
tried those, but ebay have moduls which could be used.
>
> Any suggestions?
>
> Ola
>

Hi Ola,

No storage on board but a 40-Pin IDE connector?
So you can connect an IDE HDD or an IDE to CompactFlash converter.
It will be easier to develop the software for a 16-Bit parallel device
and the data transfer rate will be higher but it uses a lot of I/O.

or maybe a SD-Card with a 4-Bit parallel interface?

--
Marc

Ola Hollum

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Mar 4, 2016, 6:13:54 PM3/4/16
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But before software, how easy is the hardware interface? Can the 680x0 controle the IDE directly? How much glue chips would be involved? Would a GAL or a PIC be able to bridge the gap?

Ola Hollum

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Mar 4, 2016, 6:30:44 PM3/4/16
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On Saturday, March 5, 2016 at 12:13:54 AM UTC+1, Ola Hollum wrote:
> On Tuesday, March 1, 2016 at 9:00:49 AM UTC+1, Marcopolo wrote:
> > Le 29/02/2016 22:57, Ola Hollum a écrit :
> > > HI,
> > > But some permanent storage must be present, maybe SD-card? Never
> > tried those, but ebay have moduls which could be used.
> > >
> > > Any suggestions?
> > >
> > > Ola
> > >
> >
> > Hi Ola,
> >
> > No storage on board but a 40-Pin IDE connector?
> > So you can connect an IDE HDD or an IDE to CompactFlash converter.
> > It will be easier to develop the software for a 16-Bit parallel device
> > and the data transfer rate will be higher but it uses a lot of I/O.
> >
> > or maybe a SD-Card with a 4-Bit parallel interface?
> >
> > --
> > Marc
>
> But before software, how easy is the hardware interface? Can the 680x0 control the IDE directly? How much glue chips would be involved? Would a GAL or a PIC be able to bridge the gap?

Marcopolo

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Mar 5, 2016, 3:30:02 AM3/5/16
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Le 05/03/2016 00:13, Ola Hollum a écrit :
>
> But before software, how easy is the hardware interface? Can the
680x0 controle the IDE directly? How much glue chips would be involved?
Would a GAL or a PIC be able to bridge the gap?
>

You can connect the IDE drive to the 68000 bus with 2 buffers and a GAL
like in Atari ST interface: http://atari.8bitchip.info/aidesch.htm

Ola Hollum

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Mar 6, 2016, 3:42:55 PM3/6/16
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Thanks, that could be a solution. But the board usage is rather hi, 2 buffers, a GAL and a 2*20 pin connector. Maybe the form factor will not allow such a large interface. But I will try to design it, and then we will see. A small change would be to go for the 8 bit interface (storage is cheap - and can be wasted!) saving 1 TTL.
Ola

Marcopolo

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Mar 6, 2016, 4:43:04 PM3/6/16
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Le 06/03/2016 21:42, Ola Hollum a écrit :
>>
>> You can connect the IDE drive to the 68000 bus with 2 buffers and a GAL
>> like in Atari ST interface: http://atari.8bitchip.info/aidesch.htm
>
> Thanks, that could be a solution. But the board usage is rather hi, 2 buffers, a GAL and a 2*20 pin connector. Maybe the form factor will not allow such a large interface. But I will try to design it, and then we will see. A small change would be to go for the 8 bit interface (storage is cheap - and can be wasted!) saving 1 TTL.
> Ola
>
Maybe possible without the 2 buffers:
http://atari.8bitchip.info/megastide.html



coinst...@gmail.com

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Dec 22, 2017, 8:51:26 AM12/22/17
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Hello, I'm new to m68k group. Reading through the old posts, I'm interested in how this low cost board development went. The 10cm*10cm pc board is now 50 cents/pcs. It is a powerful cost-reduction force, along with low component costs in the greymarket (e.g., eBay).
Bill

Peabody1929

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Jan 13, 2020, 1:51:06 PM1/13/20
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I am new to the group. I too am interested in the 10cm*10cm pc board. Is anyone working on it or interested in working on it?

Tom

Ola

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Jan 15, 2020, 5:58:20 PM1/15/20
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On 13.01.2020 19:51, Peabody1929 wrote:
> I am new to the group. I too am interested in the 10cm*10cm pc board. Is anyone working on it or interested in working on it?
>
> Tom

I am currently working on a 10*10 cm pcb with a 68008.

Will use a subset of Easy68K traps, in order to use same software on
68008 and in the Easy68K on a PC.

512K prom, 512K ram, 68681. Uses a GAL22V10 for logic.

Also holds a 28pin PIC so version 2 can omit PROM/UART, and use dual
SRAM (total 1MB) (same PCB).

Purpose of project it to let the PIC perform: power on reset/boot
strap+loader/serial ports/reset and abort buttons.

Such a chip will be useful and save PCB space when going for the 68EC000
and hopefully the 68030 later.

Ola


Peabody1929

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Jan 17, 2020, 2:07:29 PM1/17/20
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Hi Ola,

I'm glad to find someone else building a 68K SBC. Currently I have a 68000 system that consists of a processor board, memory board, serial board and a CF card board. The CF interface does not quite work yet. I have decided that the separate boards with one function per board is just too hard to deal with. I am starting on a 10x10 SBC design.

Another person I found is Bill Shen who is building a 10x10 68030 SBC.

URL: https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:cb030

It is called the CB030. The design includes options for 16Mb, 64MB and 128MB of RAM. Back in the day, I had a 68000 system with 128KB so these options sound WONDERFUL!

Best regards,
Tom

Greg Holdren

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Jan 17, 2020, 5:54:44 PM1/17/20
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Yup, Look on retro-comp on Google Groups for more discussion on the CB030 and other 68K/Non-68K stuff too.

https://groups.google.com/forum/#!forum/retro-comp

Greg

coinst...@gmail.com

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Jan 19, 2020, 7:56:21 AM1/19/20
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I have designed quite a number of 680x0 board in 4"x4" format since 2017. Most of them were for CP/M68K
Tiny68K, https://www.retrobrewcomputers.org/doku.php?id=boards:sbc:tiny68k
T68KRC (3"x4"), https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:t68krc
P90M, https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:p90mb
CB030, https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:cb030spec

There are also a number of experimental prototypes in either 4"x4" size of smaller
Tiny302, Tiny020, Tiny030, G8PP+68K8, X688, Kuno. Most of them are documented in retrobrewcomputers.org

MPU302 is interesting because it is reverse engineering of a commercial board and repurposed to run CP/M68K, https://www.retrobrewcomputers.org/doku.php?id=boards:sbc:mpu302
Bill
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