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Looking for 68000 or 68008 SBC

Ruud

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Nov 30, 2009
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Heerlen, NL
I used to have Amiga's but at the end I sold them. But I'm still interested in programming a 68000 or 68008 in a small scale. So I looked for a nice SBC. But the only reasonable looking one was this 68008 one. And yet I have a small complaint: it uses a PIC to emulate the ROM. A CPU, ROM, RAM, UART and TTL-glu would fine. No CPLD/FPGA but wouldn't mind a GAL.

Any pointers are welcome. Thank you in advance!
 

jdreesen

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Jul 5, 2012
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Switzerland
I can offer you a Philips OM5040, which is a Eurocard sized development system with the Philips 68070....
 

smp

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Bedford, NH, USA
There's this available on eBay, or direct from the maker:


smp
 

daver2

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I have found that the DECServer 200/MC has a 68000 CPU inside (with EPROMs in sockets). It has local RAM and plenty of serial ports. No disk interface though - but you could use a serial port to interface to a serial server.

The DECServer 300 has a 68020 - but the firmware is soldered onto the board in this case.

I have been able to find the technical information online at http://www.vaxhaven.com/images/2/2e/EK-D200C-IN-001.pdf. I also found the schematics when I went hunting at one point. EDIT: here http://www.bitsavers.org/pdf/dec/et..._DECServer_200_Engineering_Drawings_Oct87.pdf.

I was wondering myself whether this would make a nice little SBC...

Up to 512KB (Parity) DRAM.
32KW EPROM (2*27128).
2KB EEPROM (2816 device).
8 serial ports (4 * DUART).
Lance Ethernet controller.

EDIT: Found the memory map on one of the schematic pages:

1665936017989.png
The only thing that is worrying me is the GATE ARRAY area...

I might bring one home and have a play with it next time I am in work...

I have plenty of these units to give away (for a suitable donation to charity).

Dave
 
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Ruud

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There's this available on eBay, or direct from the maker:


smp
Thank you for your tip! It was mentioned on other sites but the given URL did not exist. Seeing your link I was a bit skeptical but then I noticed that the given URLs were different.
I'll first have a chat with Jos and then I'll decide what to do.
 
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Bruce Tomlin

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Jan 6, 2010
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San Antonio, TX
One of the things on my long to-do list is to make a Sega Genesis dev board of some sort. The edge connector is 62 pins, so you can use an old ISA bus slot for it.
 

Ruud

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Nov 30, 2009
Messages
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Heerlen, NL
There's this available on eBay, or direct from the maker:


smp
First: Jos will send one of his devices including documentation.

Reading the documentation I ran into something I disliked: a software UART. Why not an hardware one? Then I rather go for this one: 68K-MBC.
 

eswan

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Aug 17, 2015
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Kansas City area, US
There's always the MECB, M68000 educational computer board. Very small scale, 32k ram, rom monitor, 2 serial ports and a parallel port. They show up on everybody favorite auction site fairly often. Squirliest bit is it uses 3 voltage ram.

 

tom.storey

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Nov 18, 2022
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Location
London, UK
If you're not worried about being compatible with any other particular computer out there, I have a 68k board that I designed some time ago.

1 megabyte of ROM and RAM, 2x UART (TL16C2552 or similar, TTL levels only), a bunch of expansion slots with configurable address ranges, configurable wait states, configurable interrupt auto-vectoring, configurable option to relocate RAM to start at address 0...

It uses a handful of standard logic gates and 3x GALs. The board is about the same size as an A5 sheet of paper.

I've got an 8MHz HC000 running at 16MHz on mine, but a friend has run one up to 32MHz.

I've also been working on a GCC based "tool chain of sorts" to allow me to compile C, and I've built a simple serial based loader (using a python script) so that you don't have to keep popping ROMs to run the next iteration of your code.

Im in the UK so if you were interested I have a couple of spare boards.

Edit: The first expansion board I built for it has an RTC, battery backed RAM, Intel 8254 timers, and a watchdog timer, and have PCBs for this as well.

I started building a VGA card (prototype only) that uses a 128MC CPLD and which does work (provides 80x25 text mode 16 fg/8 bg colours), and had intended to start building an Ethernet card, but stopped there because unfortunately my board doesn't support anything else being the bus master and the Ethernet controller I was intending to use needs to become bus master to send/receive packets.

I've been considering a new design, but this board is still useful.
 
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tom.storey

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Nov 18, 2022
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London, UK
A couple of pictures of the two PCBs.
 

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