13 Dec
2005
13 Dec
'05
6:15 p.m.
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
really need?
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
WireWrap sockets
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
machine.
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 )
Laterz,
Roger "Merch" Merchberger
Just where are you that it is 30 below?