mark at cloud9tech.com
Mon Jul 7 15:07:55 EDT 2008
189's last check were not in production. I made my first 2meg board
with those and have since switched to CPLD design.
Rocket was the name as I recall of Chris Burke's project. I recall it
used the 68008 as well. Not enough orders to make the board. Details
68008 Quoting Chuck Youse <cyouse at serialtechnologies.com>:
> On Mon, 2008-07-07 at 13:22 -0500, Joel Ewy wrote:
>> Chuck Youse wrote:
>> It uses a GIME, some TTL chips, and the DAT board from a Disto 1M
>> upgrade. A cursory glance reveals no PALs or GALs.
> I have some 74S189s (16x4 static RAMs) that, in pairs, would make for a
> very GIME-like MMU (with 2MB of addressable space), minus the FExx
> fixed-page and always-map-FFEx-to-ROM features.
> My concern about designing such a system is the amount of modification
> that would be required to NitrOS-9 - in Level II in particular, the
> NitrOS team have made a lot of assumptions about the hardware platform
> and these references aren't really localized to one specific place.
> This isn't a criticism, their aim was "make it fast on a CoCo 3", a goal
> they've consistently met admirably, but that necessarily means a
> sacrifice of portability.
> It almost seems more straightforward to take NitrOS-9 Level 1 and port
> it to the 68000. I wonder if Radisys would take note of that project
> and get itchy as it could conceivably compete with their (still-current)
> OS9/68000 product, though it would probably differ in some significant
> With a 68008 @ 8MHz, there would be a noticeable (but not extravagant)
> increase in speed. There's no complexity associated with a DAT or the
> ugliness that that introduced to Level II. The upgrade path to a 16MHz
> 68000 (still available, mind you) is largely brainless, and that
> provides 16MB+ of memory space. All of this while still maintaining a
> _very_ hackable system for good fun.
>> I also have a couple of Motorola 6809 (not 6809E) EXORBUS boards, which
>> are essentially SBCs that can be plugged into a bus to hook up to other
>> stuff. I haven't done much with them yet, but I have looked into what
>> it would take to run OS-9 from ROMs. They have a bunch of sockets that
>> can be jumpered to accept (EP)ROMs of various capacities or SRAM chips.
>> No MMU or DRAM controller, but those things could be added on an
>> external board. I do have full schematics for these boards in the
>> Motorola docs. I told somebody on this list (Willard Goosey?) that I
>> would scan the docs sometime. I haven't done it yet, but haven't
>> forgotten either. So maybe it's time to do a bunch of scanning...
> A basic 6809 system is rather easy to construct - a non-DAT system with
> 64K of RAM to run Level-1 would be a one-day project, assuming you have
> the parts. Might be more trouble than it's worth to try to use those
> EXORBUS boards, who knows.
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