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RE: [N8VEM-S100:628] Re: S-100 68K CPU board status

Hi Dave, I don't remember any major issues with the original V1 board. If
you have the Wilcox book and do it step by step as he describes it makes it
really easy.  I have written most of the major stuff up here:-


The only thing was a screw-up with the wait state circuit around U33. The
labels were  duplicated and confused the router. I am attaching the more
elaborate V3 prototype schematic (runs as a master/slave), ignore most of
the stuff but you should see how U33 inputs should be.

Great you will give the software a shot.  You might want to consider the
basic monitor I wrote as a basis to splice in the code for the IDE board.
It?s already setup for the Console I/O board.  Look at my 8086 code to get
you started. See here:-


Frankly I found the Motorola monitor too convoluted and complex and way
overkill for what we need.

On the above page is a link to the monitor and the completely self-contained
windows compatible IDE 68K assembler
(Easy68K) Runs like a charm!

Good luck

John Monahan Ph.D

-----Original Message-----
From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On
Behalf Of yoda
Sent: Wednesday, December 28, 2011 1:51 PM
To: N8VEM-S100
Subject: [N8VEM-S100:628] Re: S-100 68K CPU board status

Hi John

I plan on taking a stab at getting CP/M 68K up and running as well.
Andrew just sent me one of the v1 68K boards so I should have in a few days.
I think I have all the parts on hand to put it together.  Do you have any
errata on changes you have had to make to the base board to get it
functioning (that would speed up rediscovery of things you have already
found).  I plan to bring up with serial I/O board and IDE card with CF disk.
I will move to propIO when I have a chance to breadboard my design - it is
simpler than yours and is a variant of the one I did for the N8VEM.  I plan
to add 2 IDE CF cards to the same board so I will have the majority of the
I/O I need on a single card - don't know whether I will do that first or the
68K board - probably the 68K board first


On Dec 28, 1:14 pm, "John Monahan" <mon...@vitasoft.org> wrote:
> That?s great on the 68K board Andrew. I'm running into some real 
> headwinds with the VGA board. Already extensive mods on the prototype 
> and I'm still not even accessing the EEPROMS! There are some strange 
> things going on with
> 16 bit word access on odd/even addresses.  So when the 68K and MSDOS 
> support boards are optimized I may be ready for a break to something
> I was kind of hoping somebody here could take up the challenge of 
> getting a basic CPM68K going with our IDE board and Console I/O board 
> using the CompuPro BIOS. Should not be too difficult. That way I can 
> concentrate on hardware.  My goal for next year will be to have 32 bit 
> Intel & Motorola CPU chips on the S-100 bus.  It's going to need a lot 
> of hardware time (and prototype boards).
> John
> John Monahan Ph.D
> mon...@vitasoft.org
> -----Original Message-----
> From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] 
> On
> Behalf Of lynchaj
> Sent: Wednesday, December 28, 2011 4:04 AM
> To: N8VEM-S100
> Subject: [N8VEM-S100:614] Re: S-100 68K CPU board status
> Hi John!  Thanks!  Wonderful news!
> Yes, the CompuPro documentation is excellent as is the DRI material.
> It seems the "default" case in the DRI documentation is a $0400 loader 
> and a 128KB version of CP/M-68K.  If the same can be done with the 
> CompuPro binary images that would be a good place to start.
> Assuming you are using an S-100 4MB SRAM board, the most direct path 
> may be to just use the debug monitor to load the default CP/M-68K 
> binary image into RAM and tweak the CBIOS from there.  The DRI 
> documents say for a "bare bones" CP/M-68K the CBIOS needs about a 
> dozen functions or so like the console in and out and those for the disk.
> I imagine the code required for interfacing to an S-100 IDE or S-100 
> ZFDC could be considerably simpler than a Disk1A.  Still a lot of work 
> but doable.
> Once even a bare bones CP/M-68K is running then its own tools are 
> available to help fill out the rest.  Its that first step that's the big
> Good news on the S-100 68K CPU board PCB trace routing.  As of last 
> night there were 584 vias and overall trace length at 1450" or so.  At 
> the rate it was going it should complete a full pass in 2-2.5 days.
> This is huge progress and the board has finally turned the corner.  It 
> still needs to lose about 200 vias to be even reasonable to make a 
> prototype but at least it is visibly moving.
> This is very exciting.  With Leon's Z80/8086 multiCPU running "in the
> I can see a day in the not to distant future of a Z80/8086/68K 
> multiCPU
> S-100 system.  More to come for sure!
> Thanks and have a nice day!
> Andrew Lynch
> On Dec 27, 5:13 pm, "John Monahan" <mon...@vitasoft.org> wrote:
> > My first choice would definitely be using the Godbout 68K image and 
> > splicing in a BIOS written in assembly. The Godbout/CompuPro systems 
> > we're outstanding. The documentation was great with great examples.
> > That would be my first choice. It would be real easy to splice a 
> > BIOS into the very simple monitor I wrote,  see here:-
> >http://s100computers.com/Software%20Folder/68000%20Monitor/68000%20Mo...
> > tm
> > As to a windows based 68K assembler. I would highly 
> > recommendhttp://www.easy68k.com/
> > It is just fantastic for a job like this.
> > John Monahan Ph.D
> > mon...@vitasoft.org
> > -----Original Message-----
> > From: n8vem...@googlegroups.com 
> > [mailto:n8vem...@googlegroups.com]
> > On
> > Behalf Of Mike
> > Sent: Tuesday, December 27, 2011 12:47 PM
> > To: n8vem...@googlegroups.com
> > Subject: Re: [N8VEM-S100:607] Re: S-100 68K CPU board status
> > On 12/27/2011 03:28 PM, lynchaj wrote:
> > > Woof!  OK, that's weird.
> > > My guess is Alcyon C compiler is really old and predates much of 
> > > the now more standardized C conventions.
> > > I've never seen or heard of anything like you just described.  
> > > This must be really obscure stuff.
> > > Here is a post on comp.os.cpm which seems to discuss the unnamed 
> > > structs
> > >http://groups.google.com/group/comp.os.cpm/msg/398560ac7ef058b6
> > > Forgive my ignorance but do you think the Alcyon C compiler is 
> > > capable of successfully compiling the CP/M-68K sources?
> > > Thanks and have a nice day!
> > > Andrew Lynch
> > Ha. Okay, so I'm not alone! :)
> > Yes, I would say almost certainly it should be able to compile the 
> > CP/M-68K sources, as it appears to be the exact compiler used to 
> > compile them originally.
> > --Mike
> >http://8bit.zapto.org-Hide quoted text -
> > - Show quoted text -

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