bfranchuk at jetnet.ab.ca
Tue Dec 13 12:15:28 CST 2005
Roger Merchberger wrote:
> Firstly, I'd like to mention that I've always wanted to build my own
> homebrew 6809 system... altho I've been thinking of designing my own
> buss system (around 80 pins or so) so other CPUs could be used if
> desired. I was thinking of a multi-board system with a 6-7 socket
> backplane. I want it to be educational to others (read: see-thru
> Lucite case & lotsa Blinkenlights! ;-) at the same time that I learn
> from it, too.
The XT connectors can be got cheap. For a 8 bit CPU how many pins do you
Only I/O need go on the backplane - 32k x 8 ram is dirt cheap and too
fast for a 2 MHZ 6809.
Now a 4 MHZ 6809 ( that are not made ) would be just about right.
> For a few reasons, S100 is not an option: I want the system smaller /
> easily portable (I'm guesstimating in inches: 6x6x9, with an external
> 5V only switcher), and I also want it to be easily buildable by a
> hobbyist. Trying to dremel an S100 cardedge would seem to be quite a
> bit of work for not a lot of gain - but square boards with a pair of
> 40-pin IDE connector (for example) edge-soldered on would be pretty
> easy to do at home.
I think protype PCB's are still better as when you add up the price for
I think works out the same ballpark figure. I think the time doing a
PCB is longer but
less hassle since mistakes in wire wrapping are very hard to find.
> I do have a question:
> Are there any 80-100 pin buss structures already in use I could copy
> that might fit my bill? I'd rather do something that might be
> compatible with something else out there if it's similar enough to
> what I want to accomplish.
> I'm hoping to take lots of pictures & basically make the design free
> on the web as I do this, mainly to show people if an idiot like me can
> make a computer, so can you! ;-)
That is my line.
> Oh, and for the record: Cubix looks *kewl*. ;-)
> Them's fightin' words. 64K w/OS-9 got me thru High school & my first
> year of college, before I got my CoCo3 & 128K (later to 512K) but I
> still had a maximum 64K code space - and that kept me working until
> the mid-90's. Other than running (crawling) Autocad, my '386 was the
> 'toy' and my CoCo was the workhorse. Once I got an EISA 486-66 server
> from my (then current) employer, did I consider the CoCo my secondary
The crappy hardware on the COCO keeps it a toy.
> A few of those microcontrollers have 128K of flash on 'em now.
> I want my CoCo on a chip! ;-)
I want a Gimix! ( I think that is how it was spelled )
> Roger "Merch" Merchberger
Just where are you that it is 30 below?
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