[Coco] TC-9

[Mark Marlette]

Chuck,

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  
foggy.....

Mark
Cloud-9

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

> ways.

>

> 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.

>

> C.

>

>

>

>

>

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