[Coco] OS9 on EP4CE6 board

Dave Philipsen dave at davebiz.com
Fri Sep 9 16:42:21 EDT 2016

On 9/9/2016 3:21 PM, Neal Crook wrote:
> Hi Dave,
> just to clarify, my work has been on a Cyclone II board:
> https://www.retrobrewcomputers.org/doku.php?id=boards:sbc:multicomp:cycloneii-c:start

Oh, ok. I thought you had picked up one of these: 
I guess it was Kip who turned me on to that one.

> Here is the current status for you (and anyone else who's interested)
> Level 1 boots reliably. It supports multiple virtual floppy disk images
> from an SD card (including booting from track34 on on of those disk
> images). It supports the serial ports and the pseudo-serial port VGA/PS2
> hardware. It gets its periodic timer interrupt from logic that I added to
> Grant's original design. I wrote a utility to initialise the time from the
> RTC chip (this can be done by a script at startup).

I've played around a little with Grant's VGA code and got it to do 80 x 
30 instead of 80 x 25.  A little clumsy though since you have to 
allocate more of the internal FPGA memory if you're using color. I'm 
also playing around with a 800 x 600 mode that has a 50 MHz dot clock as 
opposed to the 25 MHz dot clock of Grant's project.  I'm able to 
generate the VGA signal and twiddle individual bits on and off in 256 
different colors but I haven't added the character generator yet.  I'm 
trying to do it myself instead of copying Grant's code so that I can 
fiddle around with it a little more.  It will display an 8x16 font at 
100 chars. wide by 37 chars high.  I don't think I will have any 
problems getting it to function in the same manner as Grant's project 
emulating a UART but I don't know yet if I can get the video memory to 
map as the CPU memory a la Coco. It should be doable but I have to get 
the 6809 running on a gated 50 MHz clock.  Still 25 MHz but with a 25/75 
duty cycle.

> I wrote an MMU that is functionally compatible with the COCO MMU but I have
> not made any progress on a Level 2 port. Bill Nobel started looking at it
> but the last update I heard from him was in February so I suspect that
> (like me) he has become distracted by other projects.
> In the mean-time, leveraging work by Tormod and Brett Gordon, I have ported
> FUZIX to the cyclone II multicomp. This is running quite nicely (and makes
> use of the MMU code). The FUZIX port includes Drivewire support (again,
> porting stuff from Tormod and Brett) which makes me confident that I could
> easily add drivewire support to my NitrOS9 Level 1 port.
> In addition, I have extended the exec09 emulator that I use for development
> so that it can now work with non-blocking I/O and can support a timer tick
> interrupt -- both of these were to help my FUZIX work but they also solve
> problems that made it difficult for me to develop the Level 2 code in
> emulation.
> All my code changes are available on request to anyone who wants to examine
> or extent them. I think that I should attempt to get them into the official
> sourceforge tree. Everything else that I've mentioned here (board design,
> RTL, and all the otehr source code) is already freely available from my
> github repository and its associated WIKI.
> https://github.com/nealcrook/multicomp6809
> https://github.com/nealcrook/exec09
> regards,
> Neal.

Thanks for the update, Neal.  Cool stuff.  I, too, have been busy with 
"stuff" and haven't had a chance to try your project out.  If you get 
Level 2 running even without the graphics I'd love to hear about it.


> On 9 September 2016 at 20:51, Dave Philipsen <dave at davebiz.com> wrote:
>> So, Neal, I am eager to hear about what's been going on with the Cyclone
>> IV project.  Last I heard you had been successful in booting Level 1 on
>> it.  Any further progress?  Do you have the SD card working under OS9?
>> Dave
>> On 9/9/2016 8:43 AM, Neal Crook wrote:
>>> cheers,  brett
>>>> aka Mr D. Morgan
>> --
>> Coco mailing list
>> Coco at maltedmedia.com
>> https://pairlist5.pair.net/mailman/listinfo/coco

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