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

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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

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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 controle the IDE directly? How much glue chips would be involved? Would a GAL or a PIC be able to bridge the gap?

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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?

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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

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On Saturday, March 5, 2016 at 9:30:02 AM UTC+1, Marcopolo wrote:

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

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

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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

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On Monday, February 29, 2016 at 2:57:34 PM UTC-7, Ola Hollum wrote:

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

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

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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

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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

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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

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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

On Friday, January 17, 2020 at 11:07:29 AM UTC-8, Peabody1929 wrote:

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

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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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