6809 mill clone

[Alex Freed]

Another update. After a lot of frustration trying to figure out what can
stop the OS9 disk from running I'm pretty sure that the one image
floating around the 'net is broken as it tries to start the 6809
executing at an address that was never loaded.

So I had to think of another way of making sure my board works. I have
assembled a small interface program from the Mill manual that runs on
the 6502. It reads the keyboard and writes to the display via a monitor
call COUT1. The second part is 6809 code using two memory locations as
mailboxes to read incoming bytes left there by the 6502 and to write
output to the outgoing mailbox. The 6809 assembler I used (found at
http://koti.mbnet.fi/~atjs/mc6809/) was "A09". The archive came with a
few examples including "Tiny BASIC". So I assembled it replacing the i/o
calls with ones working via the 6502 interface. A great success :)
The Tiny BASIC is running just fine proving that my 6809 board is
operational. Of course it also runs the counting demo from the Mill
floppy once I adjusted the addresses.

That's the good news. The bad news is that as I said before the 6809
CPUs for sale at Jameco are NOT the "E" type, so they are not suitable.
I can order a minimum of 10 CPUs from a different source once I have the
orders.

It is $80 including domestic shipping. Or for $25 you can buy a raw PCB
plus a programmed CPLD and assemble your own.

I think everyone who expressed an interest knows my PayPal account.


-Alex.

[Egan Ford]

Will you please release the before and after source code? Binaries too.

[A2CPM]

Hi, y'all!

<BLATANT_PLUG>
If you're interested in this card, you need to join the Yahoo!
Apple 6809 group. That is, if you haven't already done so. Getting
OS/9 running on this new card will not be easy, given that the
existing OS/9 Apple II disk image is now known to be faulty. The
'Files' sections of the group has files that are vital to the process
of getting OS/9 and other major programs running on the Alex Freed
6809 card.
</BLATANT_PLUG>

Willi

[Michael J. Mahon]

I hope that all the discussion doesn't leave csa2--that would really shrink
the number of eyes...

-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon

[A2CPM]

Hi!

On Jul 26, 2:00 pm, Michael wrote:
> I hope that all the discussion doesn't leave csa2--that would really shrink
> the number of eyes...

The primary reason I started the Yahoo! Apple 6809 was to serve as
a collection point for files related to running a 6809 CPU in an Apple
II. Currently, such files are scattered all over the Internet. Some
worthwhile sites, such as HackZapple, have broken links for disk
images. Most of the images no longer available at HackZapple have
been recovered and are now available in the group's 'Files' section.
The image of the Apple Pascal disk containing a dual 6502/6809 P-code
interpreter was found shortly after the group was formed. Would the
image have turned up if the group had not been formed? Who can say?

I believe the group will be a valuable resource for the CSA2
community so I will continue to promote it while trying not to be
obnoxious about it.

Willi

[Antoine Vignau]

If you want the hackzapple's images, just ask ;-)
antoine

[A2CPM]

Hi!

On Jul 26, 3:24 pm, Antoine wrote:
> If you want the hackzapple's images, just ask ;-)

Gee, NOW you tell me...

Willi

[Alex Freed]

On 7/26/2012 6:05 AM, Egan Ford wrote:

>
> Will you please release the before and after source code? Binaries too.

Sure. I'll put everything on my web page.

-Alex.

[Egan Ford]

On 7/26/12 1:24 PM, Antoine Vignau wrote:
> If you want the hackzapple's images, just ask ;-)
> antoine
>

OS9PRACT.DSK and OS9.DSK.

I cannot find OS9PRACT anywhere and perhaps it will boot. Also I want
to check the md5sum on your OS9.DSK and see if it is different from the
others floating around.

Thanks.

[Egan Ford]

Thanks. URL? I cannot seem to find it. Thanks again.

[Antoine Vignau]

They may contain the same disks but I see two entries from where I stand :-)

http://www.brutaldeluxe.fr/public/mill6809.zip

http://www.brutaldeluxe.fr/public/os9.zip

Antoine

[Alex Freed]

Great! There are a lot of images there that I didn't find before. That's
the good news. The bad news is that I took a quick look at all the
images that are supposed to boot OS9 and they all have the same bytes at
the 0x14FE, 0x14FF.
From the boot sector disassembly (and actual observations) it is clear
that 4 sectors worth of 6502 code is loaded from $C00 to $FFF. And 48
sectors of 6809 code starting at $9000 right up to the end of the 48K.
The last 2 bytes at $FFE-FFF are the reset vector for the 6809 assuming
my information about the memory remapping is correct. It comes from here:
http://www.hackzapple.com/ORG1/M2/COPROC/6809MILL.HTM

----------
Sans cette carte fille, la carte Stellation Mill a deux cartographies
d'adresses : la premi�re identique � celle du 6502, la seconde inverse A15.

La cartographie OS/9 est la suivante :
6809 6502
0xxx 1xxx
... ...
Axxx Bxxx
Bxxx Dxxx L/C
Cxxx Exxx L/C
Dxxx Fxxx L/C
Exxx Cxxx I/O space
Fxxx 0xxx ZP+stack+text
-------------

This sure makes sense. Is there code that patches those memory locations
at run time?

-Alex.

[Egan Ford]

Thank you Antoine.

[rjus...@internode.on.net]

I notice in one of the source file posted in the apple6809 yahoo group by Willi from a new disk from Antoine, the memory map seems different to that listed on the hackzapple page.

Might be worth a try.

************************************************
*
* APPLE II REMAPPING ROM, V1.0 (1/82)
*
* THE BELOW SYMBOLS MUST BE USED IN DRIVERS, ETC
* TO ACCESS MEMORY WITHIN 6502 SPACE.
*
REMAP0 SET $C000 6502'S 0XXX = CXXX FOR 6809
REMAP1 SET $0000 6502'S 1XXX = 0XXX FOR 6809
REMAP2 SET REMAP1+$1000
REMAP3 SET REMAP2+$1000
REMAP4 SET REMAP3+$1000
REMAP5 SET REMAP4+$1000
REMAP6 SET REMAP5+$1000
REMAP7 SET REMAP6+$1000
REMAP8 SET REMAP7+$1000
REMAP9 SET $D000 START OF OS9 (TOP 12K OF 48K)
REMAPA SET REMAP9+$1000
REMAPB SET REMAPA+$1000
REMAPC SET $B000 APPLE CARD SLOTS & I/O FIRMWARE
REMAPD SET $8000 WITHIN OPTIONAL RAM CARD
REMAPE SET REMAPD+$1000 ALSO RAM CARD
REMAPF SET $A000 RAM CARD OR ROM

[Alex Freed]

Good catch. This sure explains the mystery of OS9 boot code:
With this new remapping the reset vector should be in Apple's $AFFF.

That happens to be $a84b. A look at HUH.LST disassembly shows that
$a84b is good 6809 code, in fact just the beginning of a code
section in what was assumed by Willi to be initialization.
Fortunately changing the memory mapping is trivial with a CPLD. I'll see
what happens now.

In other news I ordered a few 6809E chips from Hong Kong. With any
luck they should be real "E" parts.

Thanks everybody who sent me a payment. Please expect a little
delay till I investigate the memory mapping issue and more delay
till the CPUs arrive - promised in 2 weeks.

On 7/30/2012 6:06 AM, rjus...@internode.on.net wrote:

>
> Might be worth a try.
>

-Alex.

[Egan Ford]

Please take your time. No rush on my end.

[A2CPM]

Hi!

On Jul 30, 4:32 pm, Alex wrote:
> Good catch. This sure explains the mystery of OS9 boot code:
> With this new remapping the reset vector should be in Apple's $AFFF.
> That happens to be $a84b. A look at HUH.LST disassembly shows that
> $a84b is good 6809 code, in fact just the beginning of a code
> section in what was assumed by Willi to be initialization.
> Fortunately changing the memory mapping is trivial with a CPLD. I'll see
> what happens now.

<--- snip --->

Actually, "HUH.LST" is a listing generated by assembling a source
file I extracted from the original disassembly. And, it's obsolete,
having been replaced by "OS9.LST", which shows a well documented
module header. $A84B is the module's starting address. Would have
defined the address MUCH sooner had I taken the time to read the
available technical documentation BEFORE doing the original
disassembly.

Looks as if starting an Apple 6809 group wasn't such a bad idea
after all.

I'll be releasing another version of the program that displays the
directory of an OS/9 Apple disk, later today. This latest version
will display ALL the names of all the files in a subdirectory, not
just the first six.

Willi

[A2CPM]

Hi, y'all!

The latest version of "DIR" has been uploaded to the group's
site. Also included is "X", the program I used to the extract the
source file that has the remapping information. Both programs are in
"CAT9.SDK". I plan on combining the logic for both the listing and
extract programs into one.

Willi

[Alex Freed]

On 7/30/2012 2:22 PM, A2CPM wrote:
> having been replaced by "OS9.LST", which shows a well documented
> module header.

it may be worth indicating in this file that the last few bytes are the
reset and interrupt vectors. May also help disassembly to use the actual
address in 6809 memory space now that we know A800 is F800, etc.

-Alex.

[Michael Black]

On Mon, 30 Jul 2012, A2CPM wrote:


> Looks as if starting an Apple 6809 group wasn't such a bad idea
> after all.
>

Maybe, maybe not. You do realize people have disassembled the standard
OS-9, to the extent that it could be reassembled? I suspect off in that
corner wherever OS-9 is now being discussed, since "everyone" decided that
Usenet was no longer the place, includes people who run OS-9 on the Apple
II, their commanality being the operating system, not the computer it runs
under.

That's where people know about the standard modularizatin of )S-9, the
headers and all that. There likely is some very specific code to the
Apple II version, but that's a fairly small percentage. But then
understanding an OS-9 driver in general helps to understand an odd driver
like something related to the Apple II.

Michael

[Alex Freed]

On 7/31/2012 7:15 AM, Michael Black wrote:
>> Looks as if starting an Apple 6809 group wasn't such a bad idea
>> after all.
>>
> Maybe, maybe not. You do realize people have disassembled the standard
> OS-9, to the extent that it could be reassembled?

While I think here is a great place for a discussion, it's good to have
a place for a file depository. If anyone knows of a non-Apple OS9 forum,
why not post a link to it?

-Alex.

[Steven Hirsch]

On 07/31/2012 10:15 AM, Michael Black wrote:
> On Mon, 30 Jul 2012, A2CPM wrote:
>
>
>> Looks as if starting an Apple 6809 group wasn't such a bad idea
>> after all.
>>
> Maybe, maybe not. You do realize people have disassembled the standard OS-9,
> to the extent that it could be reassembled? I suspect off in that corner
> wherever OS-9 is now being discussed, since "everyone" decided that Usenet was
> no longer the place, includes people who run OS-9 on the Apple II, their
> commanality being the operating system, not the computer it runs under.

Actually, there's a rather comprehensive OS-9 clone called NitrOS-9. It was
developed for Tandy CoCo but since full source code is available a port to the
Mill might be doable.

Steve

[Steve Nickolas]

I thought NitrOS-9 needed a Hitachi 6309.

-uso.

[Alex Freed]

On 7/31/2012 2:15 PM, Steven Hirsch wrote:
> Actually, there's a rather comprehensive OS-9 clone called NitrOS-9. It
> was developed for Tandy CoCo but since full source code is available a
> port to the Mill might be doable.
>

True. However I understand that the most interesting version only runs
on CoCo3 - a model that has some MMU logic and has a minimum of 128K
RAM. That's OS9 "level 2".

In other exciting news I changed the memory map according to the
information from the "real source". What a difference a day makes! No
more hanging. Hello the OS9 prompt. "DIR" works showing that the
inter-process communication runs as it should. I have updated my web
page and included a screen-shot. Now I'm waiting for the CPUs from Hong
Kong.

-Alex.

[A2CPM]

Hi!

On Tuesday, July 31, 2012 5:49:52 PM UTC-4, Steve wrote:
> I thought NitrOS-9 needed a Hitachi 6309.

From the NitrOS-9 site:
Q. How do I know which version of NitrOS-9 is for which Color Computer?
A. NitrOS-9 supports three "levels" and two processors, yielding six potential distributions:
NitrOS-9/6809 Level 1 for the Color Computer
NitrOS-9/6309 Level 1 for the Color Computer with a 6309
NitrOS-9/6809 Level 2 for the Color Computer 3
NitrOS-9/6309 Level 2 for the Color Computer 3 with a 6309
NitrOS-9/6809 Level 3 for the Color Computer 3
NitrOS-9/6309 Level 3 for the Color Computer 3 with a 6309

Willi

[A2CPM]

Hi!

On Tuesday, July 31, 2012 5:15:30 PM UTC-4, Steven wrote:
> Actually, there's a rather comprehensive OS-9 clone called NitrOS-9. It was
> developed for Tandy CoCo but since full source code is available a port to
> the Mill might be doable.

I looked at the NitrOS-9 site, hoping to find source files. If they're there, it wasn't obvious to me. Would someone be kind enough to check the site to point out to me what I missed when I looked?

Willi

[rjus...@internode.on.net]

> In other exciting news I changed the memory map according to the
> information from the "real source". What a difference a day makes! No
> more hanging. Hello the OS9 prompt. "DIR" works showing that the
> inter-process communication runs as it should. I have updated my web
> page and included a screen-shot. Now I'm waiting for the CPUs from Hong
> Kong.
>
> -Alex.

Thats great news.

/Rob

[Egan Ford]

On 7/31/12 6:03 PM, Alex Freed wrote:
> In other exciting news I changed the memory map according to the
> information from the "real source". What a difference a day makes! No
> more hanging. Hello the OS9 prompt. "DIR" works showing that the
> inter-process communication runs as it should. I have updated my web
> page and included a screen-shot. Now I'm waiting for the CPUs from Hong
> Kong.

That *is* exciting news. Please let us know if you plan to do the
Stellation 68008 card next. :-)

[Steven Hirsch]

On 07/31/2012 06:57 PM, A2CPM wrote:

> I looked at the NitrOS-9 site, hoping to find source files. If they're
> there, it wasn't obvious to me. Would someone be kind enough to check the
> site to point out to me what I missed when I looked?

http://sourceforge.net/projects/nitros9

Look at the pulldown under 'Code'. You'll need Mercurial (free SCM tool) to
extract a local copy (directions provided).

hg clone http://nitros9.hg.sourceforge.net:8000/hgroot/nitros9/nitros9

There does appear to be a Windows client, but since I never use Windows unless
a gun is being held to my head I have no experience with it.

I agree the documentation is sub-optimal in terms of explaining this. I don't
think it would have killed anyone to simply show an example command line.

Would recommend looking at Boisy Pitre's work on porting Level 1 to the Atari
130XL (he developed a 6809 piggyback board for this).

[Steven Hirsch]

On 07/31/2012 06:03 PM, Alex Freed wrote:
> On 7/31/2012 2:15 PM, Steven Hirsch wrote:
>> Actually, there's a rather comprehensive OS-9 clone called NitrOS-9. It
>> was developed for Tandy CoCo but since full source code is available a
>> port to the Mill might be doable.
>>
>
> True. However I understand that the most interesting version only runs on
> CoCo3 - a model that has some MMU logic and has a minimum of 128K RAM. That's
> OS9 "level 2".

Heh. I wonder how much work would be required to present an Apple with
expanded memory through MMU logic in the CPLD? Would be a gas to run Level 2.

There's an enormous amount of documentation available on the Coco 3.

[Sean Fahey]

On Tuesday, July 31, 2012 4:15:30 PM UTC-5, Steven Hirsch wrote:

> Actually, there's a rather comprehensive OS-9 clone called NitrOS-9. It was
> developed for Tandy CoCo but since full source code is available a port to the
> Mill might be doable.

I'm curious as to the software people following project might be thinking of developing -- anyone?

[Sean Fahey]

On Wednesday, August 1, 2012 5:55:00 AM UTC-5, Egan Ford wrote:

> That *is* exciting news. Please let us know if you plan to do the
> Stellation 68008 card next. :-)

He's banging that one out *next* week. =P

Kidding of course...

[Steven Hirsch]

Well-behaved (i.e. use documented system calls only) OS-9 Level 1 applications
compiled or assembled for 6809 should "just work" on the Mill. At least in
theory...

There is a huge body of 6809 OS-9 code out there, written for Tandy CoCo. It
was a major sub-culture in early microcomputing and still has a considerable
number of folks active.

If Level 3 can be made to run on the Apple, it brings true, interrupt-driven
multi-tasking to the table.

[Alex Freed]

Actually I did think about it. Unfortunately there is a major problem:
68008 chips are extremely rare. There is also very little information
available on the Stellation 68008 and not much software.

I love the 68K. In fact I did a commercial design based on a 68K
derivative (DragonBall, same as used in Palm Pilot) only 10 years ago :)

Running a 68K CPU at 1 MHz with access to less than 64K of RAM would be
a shame. IMHO a proper model for a co-processor board is the PCPI -
separate memory. If I were to design a nothing compatible co-processor
board for Apple, I would put an ARM7 there: say the Atmel SAM7S256. 64K
RAM on chip, 256K flash, 50+ MHz. That would be some accelerator :)

-Alex.

[Alex Freed]

On 8/1/2012 6:57 AM, Steven Hirsch wrote:
>
> Heh. I wonder how much work would be required to present an Apple with
> expanded memory through MMU logic in the CPLD? Would be a gas to run
> Level 2.
>

I already have a soft 6809 running on the Carte Blanche at 25 MHz. Now
it's a "simple matter of software" - port OS9 to it.

-Alex.

[boisy...@gmail.com]

Hi,

My name is Boisy Pitre, and I manage the NitrOS-9 Project.

I also created the Liber809 board (http://www.cloud9tech.com/ and http://liber809.blogspot.com) for the Atari 8-bit computers, and ported NitrOS-9 Level 1 to it.

My sights were set on the Apple IIe, but now I've discovered this thread after going on IRC to seek an Apple IIe to buy in order to develop a Liber809 plug-in card for the Apple II bus.

It looks like someone beat me to it, and frankly I'm thrilled!

I'll be more than happy to help you port NitrOS-9 Level 1 to your 6809 board. NitrOS-9 is really where OS-9/6809 is at these days. I got it running on the Atari just fine, and I am confident that we can get it running on your board.

[boisy...@gmail.com]

Just a follow-up. I did some more reading and see you are trying to boot OS-9 from a floppy disk.

What I did on the Atari was to pull the bootfile down via the Atari SIO port hooked up to my Mac running DriveWire Server (https://sites.google.com/site/drivewire4/). DriveWire provides virtual disk network and terminal services to a computer running NitrOS-9, and the server is written in Java, so it can run on pretty much any computer.

If the Apple computer that you have sports a serial port, let me know what kind it is. I've written a DriveWire OS-9 subroutine module that hooks into the rbdw driver which pulls sectors from DriveWire. It should be trivial to adapt the dwio subroutine module to accommodate the serial port on Apple systems.

[Steve Nickolas]

On Sun, 5 Aug 2012, boisy...@gmail.com wrote:

> If the Apple computer that you have sports a serial port, let me know
> what kind it is. I've written a DriveWire OS-9 subroutine module that
> hooks into the rbdw driver which pulls sectors from DriveWire. It
> should be trivial to adapt the dwio subroutine module to accommodate the
> serial port on Apple systems.

The typical serial port on the Apple ][ line is the Super Serial Card
which uses a 6551.

-uso.

[Alex Freed]

On 8/5/2012 7:49 PM, boisy...@gmail.com wrote:
> Just a follow-up. I did some more reading and see you are trying to boot OS-9 from a floppy disk.

I'm very happy to read this post because as I see it the hardware is
operational but there is a real need for software drivers.

The OS9 boots fine from the floppy, but there are no easy ways to
communicate with the outside world. The serial driver should be very
easy: virtually every Apple 2e has a "super serial" card based on 6551 -
a rather standard ACIA for the 68xx hardware. A driver that could use
DriveWire over this serial port would be a great addition.
On top of that I think there is a need for a disk driver that can talk
to some modern mass storage device - say CFFA.

Before this project I knew next to nothing about the OS9. After a few
hours of playing with it and browsing the NitrOS9 sources I got pretty
interested. I'm even thinking of designing a new 6809 board for Apple
that would be similar in concept to the PCPI Applicard just as the Mill
is similar to the SoftCard. The new card should run a 68B09 at 2 MHz,
have a minimum of 128K of RAM on board, an MMC card for mass storage and
communicate with the Apple bus via a couple of shared registers.

Since this would be a unique design not compatible with any existing
hardware it only makes sense to start it if it is clear who will write
the drivers. Even before the final hardware implementation is done we
can implement such a system on the Carte Blanche.

-Alex.

[Egan Ford]

On 8/5/12 9:37 PM, Alex Freed wrote:
>I'm even thinking of designing a new 6809 board for Apple
> that would be similar in concept to the PCPI Applicard just as the Mill
> is similar to the SoftCard. The new card should run a 68B09 at 2 MHz,
> have a minimum of 128K of RAM on board, an MMC card for mass storage and
> communicate with the Apple bus via a couple of shared registers.

Put me down for one.

[Steven Hirsch]

On 08/05/2012 11:37 PM, Alex Freed wrote:

> I'm
> even thinking of designing a new 6809 board for Apple that would be similar in
> concept to the PCPI Applicard just as the Mill is similar to the SoftCard. The
> new card should run a 68B09 at 2 MHz, have a minimum of 128K of RAM on board,
> an MMC card for mass storage and communicate with the Apple bus via a couple
> of shared registers.
>
> Since this would be a unique design not compatible with any existing hardware
> it only makes sense to start it if it is clear who will write the drivers.
> Even before the final hardware implementation is done we can implement such a
> system on the Carte Blanche.

Boisy is most definitely the right person to ask about the intricacies of
OS-9/NitrOS-9 and 6809/6309 assembly programming. He's forgotten more about
it than I'll ever hope to know.

I'd love to see a minimum of 512k on such a card, and it goes without saying
that I want one :-).

Steve

[Alex Freed]

On 8/6/2012 3:12 PM, Steven Hirsch wrote:
>
> Boisy is most definitely the right person to ask about the intricacies
> of OS-9/NitrOS-9 and 6809/6309 assembly programming. He's forgotten
> more about it than I'll ever hope to know.
>
> I'd love to see a minimum of 512k on such a card, and it goes without
> saying that I want one :-).
>

I agree, the same way as my PCPI clone takes either 128K or 512K chips.
One question is how to implement the memory management. There seems to
be a standard in the 6809 world where the space at $FF00 (?) contains 16
write-only registers that map logical 4K blocks to arbitrary physical
memory. That would require a lot more resources to implement than is
available in simple CPLDs easy to hand solder. Another extreme is a
single 32K block mappable to physical RAM. I wonder what is the minimum
for OS9 level 2? I guess reading the CoCo 3 manual may help.


-Alex.

[Steven Hirsch]

Actually, the Microware OS-9 manuals would probably be of more general help,
as would talking with Boisy.

Have you found the Malted Media ftp site yet?

ftp://maltedmedia.com/coco/

Look in "MANUALS/MICROWARE".

You will also be interested in "Toolshed", a PC-based cross-development tool
chain for 6809/6309. I think there's a Windows build available.

http://sourceforge.net/projects/toolshed/

It would be ideal if the proposed card could run non-graphical CoCo apps. I'm
not sure what percentage of 6809 OS-9 applications are "well behaved", i.e.
operate only through documented OS entry points.

[Michael Black]

If you're not going to use more than 64K of RAM, you might as well just
use Level I. There are probably some other advantages to Level II, but
the key thing was that you could use more RAM. Level II needs the memory
management.

On the other hand, the SWTP 6809 implemented memory management by putting
RAM on the highest bits of the address bus, I think they used 7489s which
were small blocks of RAM 4 bits wide (I may not remember the details
properly). By feeding data into the RAM, it controlled the output. I'm
sure information can be had. Jim Stark had a long running series on the
SWTP computers in Kilobaud (maybe it had turned to "Microcomputing" by
then), which was more like a column, and he covered that memory management
at one point. It at least provides the concept of what's needed.

Michael

[Michael Black]

The limitations in the old days were in part the cost of RAM, which no
longer figures in. The CoCo was probably the most popular computer to run
OS-9, yet when the CoCo III was released, it allowed for relatively large
chunks of RAM, 8K. That's good for large programs, lousy for small ones,
and it was simply because the hardware did it in 8K chunks. Later, there
was some modification, I never saw it, to allow more RAM, that was later
when RAM was much cheaper.

So the best solution is to allow for more RAM, but also smaller chunks of
segments.

Michael

[Rob Justice]

For the memory mapping, the swtpc method you mention would be a good option. If you haven't seen it already, the www.swtpc.com web site has schematics of the MP-09 cpu board. If this scheme is used then perhaps the competitor operating system uniflex may be able to be ported over. This would be a big challenge, but the source is available for this, so who knows.

I had a look for the coco3 memory mapping scheme, its not something i've ever really looked into. Seems it uses 8k memory pages(instead of 4k for the swtpc), but has two tasks, so a similiar amount of memory would be required to implement it.

One nice thing to have would be some sort of common ram access like the Mill. This may be difficult if running the 6809 at 2mhz. It may need some sort of speed control for memory access to specific addresses.

i'd also be interested one if it gets built.

/Rob

[dirk.d...@scarlet.be]

Hello everyone, long time ago in 1982 i made durin my education an 6809 micro controller kid. As of today i take ik from time to time out of the box and contignue to change the hw and fw. For the fw i work in assembler with meta16 program on an old dos pc.
Ik worried that soon this dos pc will stop working and that i wil be blokked to contignue from time to time.
I have 2 questions:
First, do you know an assembler that i could use on mij win7 pc + a program that i can use to communicate in rs232 to mij 6809 kitt?
Second: does their exist an pascal compiler for 6809 that i could use? Prefered also under win7. If not maiby under dos. This could simplify the programming today in assembler(till my dos pc will stp working)

Thank in advance for any help fron an experiaced 6809 user.
Does their exist in Belgium an 6809 workgroup that i could join?
Please communicate via email to dirk.d...@scarlet.be