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  #11  
Old 04-10-2008, 07:48 PM
Grant Stockly Grant Stockly is offline
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I've been thinking about building an SBC out of all DIP parts that could run linux. Using a 64pin 68000, 32pin 512kb SRAM, etc. An inexpensive kit that has something in common with modern tools and software would be fun. A true "modern" computer kit. I wanted to limit it to DIP/PLCC/through hole parts since even coarse pitch SOIC parts are hard for some people.

I have had this idea since before the Altair kit ever came. Now I'm thinking it would be neat to have a 68000 and some memory on an S-100 card so that the Altair can run linux.

I know of at least one case where uCLinux has run on a 68000, but the FPGA company who built it for their core doesn't want to share the kernel patches.

I only suggest the 65816 because there are already a few 6502 kits out there.

I've been thinking about selling my Altair 8800 kit prototype. Its taking up space and I don't think I need to keep it for "memories". If you or anyone are interested, let me know.

One thing I would like to make in the future is a 6502 CPU board that is 100% compatible with the original Altair. This would allow a modified version of the Wozniak Apple 1 monitor to run on the Altair. If you prototyped your S-100 card in an Altair you would help accelerate me to that goal.

I would probably have a 6502 CPU chip, buffer chips, and a spot for a medium sized FLASH chip AND a 1702. The woz monitor would be
modified to use the 2SIO.

There IS a version of "CP/M" for the 6502. It would also be neat to run that!

Too many ideas and not enough time!

This is the prototype that I would be interested in getting rid of...

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  #12  
Old 04-10-2008, 10:10 PM
sje sje is offline
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Default 68000 DIPs

It's Freescale that owns the 68000 IP, and they don't make DIPs of any kind. Old 68000 DIPs can be had, possibly salvaged from old Macs, Amigas, etc., for about US$20 each.

Anyway, a 68000 really needs a 68551 MMU to do Linux, and even that's a little clunky. I wouldn't try it with less than a 68030 as the base chip, and that was never made in DIP form.
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  #13  
Old 04-10-2008, 10:22 PM
sje sje is offline
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Default S-100 and the 6502

The S-100 bus had too many problems physically, electronically, and logically. That's why it died out so quickly. Designed for the 8080, and not very well at that, it is a piling of kludge upon kludge to make the S-100 bus work for a 6502, 65856, or 68000.
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  #14  
Old 04-10-2008, 10:25 PM
sje sje is offline
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Quote:
Originally Posted by Grant Stockly View Post
I know of at least one case where uCLinux has run on a 68000, but the FPGA company who built it for their core doesn't want to share the kernel patches.
Failure to share in this case is very likely illegal due to GPL conditions.
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  #15  
Old 04-11-2008, 12:21 AM
Grant Stockly Grant Stockly is offline
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Quote:
Originally Posted by sje View Post
It's Freescale that owns the 68000 IP, and they don't make DIPs of any kind. Old 68000 DIPs can be had, possibly salvaged from old Macs, Amigas, etc., for about US$20 each.

Anyway, a 68000 really needs a 68551 MMU to do Linux, and even that's a little clunky. I wouldn't try it with less than a 68030 as the base chip, and that was never made in DIP form.

For uCLinux you wouldn't need an MMU. That means its just an application host and not a development environment, but could still be fun. Possibly more useful than an 8080???

PLCC versions of the 68LC000 are available from DigiKey, and they are 100% compatible with the old Macintoshes. I even built a carrier board and ran a Macintosh on one.

The DIP versions are available from second source places like Unicorn.

http://www.unicornelectronics.com/IC/68000.html

I buy ALL of the ICs for my kits from Unicorn.

I would rather buy an old DIP 68000 than a new PLCC 68LC000...because a 68 pin DIP is just TOO cool...
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  #16  
Old 04-11-2008, 12:24 AM
Grant Stockly Grant Stockly is offline
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Quote:
Originally Posted by sje View Post
Failure to share in this case is very likely illegal due to GPL conditions.
If they sell it they are required to make the soruce code available to their customers, but as far as I could tell they just did a report and listed the fact their core booted and ran a full blown uCLinux as a test of their cores compatibility.

Here is the page.

http://www.dcd.pl/ashow.php?page=uclinux_d68000

If you can help them to give us the code, that would be great!
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  #17  
Old 04-11-2008, 12:26 AM
Grant Stockly Grant Stockly is offline
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Quote:
Originally Posted by sje View Post
The S-100 bus had too many problems physically, electronically, and logically. That's why it died out so quickly. Designed for the 8080, and not very well at that, it is a piling of kludge upon kludge to make the S-100 bus work for a 6502, 65856, or 68000.
Its already enough of a stretch to throw a 68000 on an S-100 card and say "Altair runs Linux". It has to at least get power from the S-100 bus and make the lights blink!

Imagine it, with Linux the Altair would finally be Slashdot worthy.
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  #18  
Old 04-11-2008, 12:28 AM
Grant Stockly Grant Stockly is offline
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I think it may be a 64 pin DIP, which is still better than a 68 pin PLCC.
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  #19  
Old 04-11-2008, 09:04 PM
sje sje is offline
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The Unicorn Electronics link is inviting, but I checked and all of their catalog pages are at least a year old. So maybe the stock counts are not really up to date.

If someone uses GPL code but never releases the product, then they're in the clear.

Until the advent of the fairly well specified PCI bus, all earlier microcomputer buses were either too slow, too big (VME), proprietary (IBM micro-channel), or just plain crap (S-100, ISA). The only exception is the MIT NuBus that was used in the early slot days of Macintosh computers, and even that bus was a little slow (33 MHz).

It would be possible to run Unix/Linux on a 4 KB 8080 with enough mass storage; simply write a small interpreter that's powerful enough to run an interpreter for a 68K or some other process, and have that interpreter run the OS and applications. Maybe it would be better to have 16 KB 8080 and only run one interpreter. I've heard of one Mac enthusiast who ran a PowerPC interpreter on an ancient 68K Mac and it boots OS/X. It runs a couple hundred times slower than the real thing.
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  #20  
Old 04-12-2008, 12:58 AM
Grant Stockly Grant Stockly is offline
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The thought of Vista on an IBM PC or Mac OS X on a Lisa has crossed my mind.
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