[Coco] FW: My 6809 Computer is Working!

johnchasteen at juno.com johnchasteen at juno.com
Fri Jul 27 13:03:21 EDT 2012


On Thu, 26 Jul 2012 22:06:24 -0400 "Kip Koon" <computerdoc at sc.rr.com>
writes:
> Thanks guys.  Your very kind words mean quite a bit coming from 
> fellow 8-bit
> Microprocessor enthusiasts like yourselves, especially when you've 
> published
> your work on the internet.  I'm looking forward to seeing what 
> fascinating
> microcomputer designs you guys come up with next. I pray blessings 
> on all
> your efforts.
> 
> Kip
> 
> From: Paulo Lindoso
> Sent: Thursday, July 26, 2012 8:37 AM
> Subject: Re: [Coco] FW: My 6809 Computer is Working!
> 
> Absolutely!
> 
> These days i get happy just to spare 10 minutes to READ the list... 
> ! (and
> post an odd useless remark ;) )
> 
> Cheers
> Em 26/07/2012 03:17, "Erturk Kocalar" <erturkk at kocalar.com> 
> escreveu:
> 
> > Hi Kip,
> >
> > I envy you soo much.  You can find time to work on fun projects 
> and 
> > keep us upto date.  Keep on going.
> >
> > It's depressing for me but I'm happy to read your adventures ;)
> >
> > Good luck,
> > Erturk (Simon6809 and Simon6809 Turbo ;))
> >
> > Sent from my iPhone
> >
> > On Jul 25, 2012, at 6:59 PM, "Kip Koon" <computerdoc at sc.rr.com> 
> wrote:
> >
> > > John,
> > >
> > >
> > >
> > > Thank you so much for your suggestions.  I was concerned about 
> the 
> > > ACIA being so low in memory also made me think a about it before 
> I built
> it.
> > > Since I had never built an 8-bit 6809 computer from scratch 
> before 
> > > and
> > this
> > > one had been designed and built with a nongraphic version of 
> Tandy's 
> > > Extended Color Basic in it that was the clincher.  I cut my post 
> 
> > > college computer learning years on Tandy's Color Computers.  At 
> one 
> > > time I had a Coco1, 2 and 3 with 4 floppy drives and a 20BM MFM 
> hard 
> > > drive too.  I thoroughly enjoyed that computer.  So to make a 
> long 
> > > story short, I
> > figured
> > > I could alter the placement of the I/O later once I get my 
> > > proverbial
> > tooth
> > > cut building Grant's 6-chip 6809 computer to the $FFxx region.
> > >
> > >
> > >
> > > In my next project I'll be building SiMon6809 which has a USB 
> port
> > placed at
> > > $D000 which for me is still too low.  The link to Simon6809 
> appears
> > below:
> > >
> > >
> > >
> > > http://www.8bitforce.com/simon6809/
> > >
> > >
> > >
> > > But after it is working , I'll be moving that USB port up to the 
> 
> > > $FFxx region or maybe the $Exxx like SWTPC computers.  I'm not 
> sure 
> > > yet. Maybe eventually I could create a dual memory map version.  
> 
> > > That could be a
> > very
> > > interesting but complex learning experience.  I'd definitely 
> create 
> > > some more wrinkles in my brain working on it. J I'm waiting on 
> some 
> > > supplies,
> > so
> > > it could be a little while.  In the meantime, I'll be brushing 
> up on 
> > > my decoding logic as it applies to 8-bit microprocessor 
> > > applications.  This
> > is
> > > so much fun.  The modern chips we have available make 
> implementation 
> > > so
> > much
> > > nicer.
> > >
> > >
> > >
> > > I have never used Flex9 or even 6800 Flex, so I never really 
> > > considered
> > it.
> > > I'll have to look into it.  I'd like to upgrade the next version 
> 
> > > with a
> > DMA
> > > Floppy disk controller so I can run disk-based OSs Flex, OS-9 
> and
> > NitrOS-9
> > > and Uniflex.  I'm game for it all.  It will be like old times, 
> but
> > better.
> > > Isn't dreaming FUN?!  Let me go for now.  I'll keep you all up 
> to 
> > > date as things progress.
> > >
> > >
> > >
> > > Kip
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: coco-bounces at maltedmedia.com 
> > > [mailto:coco-bounces at maltedmedia.com]
> > On
> > > Behalf Of John Kent
> > > Sent: Tuesday, July 24, 2012 8:17 AM
> > > To: CoCoList for Color Computer Enthusiasts
> > > Subject: Re: [Coco] FW: My 6809 Computer is Working!
> > >
> > >
> > >
> > >
> > >
> > > Kip,
> > >
> > >
> > >
> > > You could add a floppy disk controller to it.
> > >
> > > I tend to follow the South West Technical Products Computer 6809 
> 
> > > memory
> > map
> > > in my FPGA designs as it allows for more contiguous RAM.
> > >
> > > The SWTPc has RAM mapped from $0000 to $DFFF, giving 56K of 
> RAM.
> > >
> > > $E000 - $EFFF is used for I/O. Typically I/O is mapped in 10 x 
> 16 
> > > bytes slots.
> > >
> > > They have 10 slots because they use a decade decoder (74LS42 ?)
> > >
> > > $F000 - $F7FF can be used for EPROM such as one of the OS9 boot 
> ROMs.
> > >
> > > It can also be used for a DMA Floppy disk controller.
> > >
> > > $F800 - $FFFF is used for a Boot ROM, such as SBUG.
> > >
> > > It's also used for an OS9 boot ROM if you want to run OS9.
> > >
> > > Some of the SWTPC boards use a 16 byte write only register file 
> 
> > > mapped at
> > > $FFF0 to $FFFF to map in up to 1MB of RAM in 4Kbyte blocks. The 
> 
> > > extra
> > memory
> > > can be used for running OS9 level 2 if you can get hold of it or 
> 
> > > UniFlex, although that might need a DMA Floppy disk controller.
> > >
> > >
> > >
> > > The SWTPc memory map is more intended for running the Flex disk 
> 
> > > operating system, so that things like BASIC and so on can be 
> loaded 
> > > off floppy disk into memory.
> > >
> > > I'm not sure if it's possible to design a hybrid SWTPc that also 
> 
> > > supports CoCo hardware as well.
> > >
> > >
> > >
> > > Kip, you'd be better off using $E000 for I/O rather than $A000 
> as 
> > > that
> > would
> > > give you more continuous RAM.
> > >
> > > On the SWTPC Flex9 sits at $C000 - $DFFF where you have the 
> ROMed 
> > > Basic interpreter. If you have that as RAM, you might be able to 
> 
> > > read the BASIC ROM from an I/O location and copy it into RAM. 
> You 
> > > could have two
> > >
> > > 8 bit latches/ D flip flops (74LS374s)  at an I/O location 
> somewhere 
> > > that you write the address to and read the contents of the ROM 
> back 
> > > and write
> > it
> > > into RAM.
> > >
> > >
> > >
> > > To run Flex9 you need a floppy disk controller (or an IDE drive) 
> a 
> > > 6850
> > ACIA
> > > at $E000-$E00F and that's about it. There is a lot for free 
> Flex9
> > software
> > > out there.
> > >
> > >
> > >
> > > It's a bit off the topic for the CoCo list sorry. A CoCo 1 or 2 
> 
> > > wouldn't
> > be
> > > too hard to build. the 32K SRAM chips out of a 486 cache have a 
> 20 -
> > 25nsec
> > > access time, so you wouldn't need a SAM to interleave the CPU 
> with 
> > > the
> > VDG
> > > for video accesses.
> > >
> > >
> > >
> > > John.
> > >
> > >
> > >
> > > On 23/07/2012 11:26 AM, Juan Castro wrote:
> > >
> > >> Suggestion: external clock circuitry so the much more 
> ubiquitous 
> > >> 6809E
> > >
> > >> can be used. (If the lack of MRDY won't screw up with your
> > >
> > >> multiprocessing
> > >
> > >> ideas.)
> > >
> > >>
> > >
> > >> Juan
> > >
> > >>
> > >
> > >> On Sun, Jul 22, 2012 at 2:24 AM, Kip Koon < <mailto:
> > computerdoc at sc.rr.com>
> > > computerdoc at sc.rr.com> wrote:
> > >
> > >>
> > >
> > >>> Hello Everybody,
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> I'd like to report that I finally got Grant's 6-chip 6809 
> computer
> > > working!
> > >
> > >>> It is so wonderful to actually build your own computer from 
> > >>> scratch
> > >
> > >>> and see your creation come to life and display "Hello World" 
> which 
> > >>> is
> > >
> > >>> actually the first program I typed in. J  It's kind of 
> tradition
> > >
> > >>> anyway.  I've seen several small microprocessor projects on 
> the
> > >
> > >>> internet being demoed with the standard "Hello World" message. 
>  It
> > >
> > >>> was my first C++ program years ago anyway.
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> I built the first version of my 6809 computer exactly like 
> Grant's
> > >
> > >>> 6-chip
> > >
> > >>> 6809 computer with exactly the same memory map as shown below. 
> It 
> > >>> has
> > >
> > >>> 32KB of ram at $0000 to $7FFF with the 16KB eprom at $C000 to 
> 
> > >>> $FFFF
> > >
> > >>> programmed with Grant's 6809 Extended Basic.  The Basic 
> > >>> Interpreter
> > >
> > >>> actually starts at $DB00, so there is a lot of empty eprom 
> space
> > >
> > >>> leftover for some type of monitor - 6.75KB I believe.
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> The initial memory map is as follows:
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> $0000
> > >
> > >>>
> > >
> > >>>    |          32KB RAM
> > >
> > >>>
> > >
> > >>> $7FFF
> > >
> > >>>
> > >
> > >>> $8000
> > >
> > >>>
> > >
> > >>>     |          8KB Unused
> > >
> > >>>
> > >
> > >>> $9FFF
> > >
> > >>>
> > >
> > >>> $A000
> > >
> > >>>
> > >
> > >>>     |          8KB I/O Space: MC68B50 ACIA chip is addressed 
> at
> > > $A000-$A001
> > >
> > >>> (Address Bus is not fully decoded.  The ACIA appears 
> throughout 
> > >>> the
> > >
> > >>> $A000-$BFFF address space.)
> > >
> > >>>
> > >
> > >>> $BFFF
> > >
> > >>>
> > >
> > >>> $C000
> > >
> > >>>
> > >
> > >>>     |          16KB EPROM programmed with 6809 Extended Basic
> beginning
> > > at
> > >
> > >>> $DB00.
> > >
> > >>>
> > >
> > >>> $FFFF
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> Well the obvious next step is to extend the ram up to the 
> > >>> indicated
> > >
> > >>> $9FFF limit in the design.  So I did!  I had a small supply of 
> 
> > >>> 32KB
> > >
> > >>> ram chips I had robbed from an old 486 motherboard not knowing 
> at 
> > >>> the
> > >
> > >>> time that they were 32KB ram chips.  Was I surprised when I 
> looked
> > >
> > >>> them up on the internet.
> > >
> > >>> I used one for the initial 32KB of ram and added a second one 
> at
> > >
> > >>> $8000 - $9FFF for another 8KB of ram.  Obviously I just used 
> part 
> > >>> of
> > >
> > >>> the second 32KB ram chip.  Later on, I plan to use more after 
> I
> > >
> > >>> rearrange the I/O space.
> > >
> > >>> Now
> > >
> > >>> my little 6809 computer has 40KB of ram space located from
> > >
> > >>> $0000-$9FFF!  So the memory map is modified as follows:
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> $0000
> > >
> > >>>
> > >
> > >>>    |          40KB RAM
> > >
> > >>>
> > >
> > >>> $9FFF
> > >
> > >>>
> > >
> > >>> $A000
> > >
> > >>>
> > >
> > >>>     |          8KB I/O Space: MC68B50 ACIA chip is addressed 
> at
> > > $A000-$A001
> > >
> > >>> (Address Bus is not fully decoded.  The ACIA appears 
> throughout 
> > >>> the
> > >
> > >>> $A000-$BFFF address space.)
> > >
> > >>>
> > >
> > >>> $BFFF
> > >
> > >>>
> > >
> > >>> $C000
> > >
> > >>>
> > >
> > >>>     |          16KB EPROM programmed with 6809 Extended Basic
> beginning
> > > at
> > >
> > >>> $DB00.
> > >
> > >>>
> > >
> > >>> $FFFF
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> Then I added an MC68B21 PIA chip decoded to $A004 - $A007 and
> > >
> > >>> connected an
> > >
> > >>> AY-3-8910 Programmable Sound Generator Chip to the two ports 
> of 
> > >>> the
> > >
> > >>> PIA chip.  I was having some problems with the initial testing 
> of 
> > >>> the
> > >
> > >>> PIA so I added two SN74LS244 Octal buffer chips each one 
> connected 
> > >>> to
> > >
> > >>> 8 LEDs one to each port of the PIA so I could see what the two 
> PIA
> > ports
> > > were doing.
> > >
> > >>> Well, every time I pressed the reset push button, the LEDS 
> changed!
> > >
> > >>> I hadn't even written any code what so ever nor did any exist 
> in 
> > >>> the
> > >
> > >>> eprom, so I knew something was wrong!  As you all might have 
> > >>> guessed
> > >
> > >>> I had not fully decoded the PIA chip to just the $A000-$BFFF 
> > >>> address
> > >
> > >>> range yet!  I had just decoded A3 - A0 address lines.  A15 - 
> A4 
> > >>> were
> > >
> > >>> never used.  No wonder the PIA wouldn't work correctly!  I 
> > >>> couldn't
> > >
> > >>> hardly believe I had made such a gross mistake.  Therefore, 
> the 
> > >>> PIA
> > >
> > >>> chip appeared everywhere in the 64KB address space.  The funny 
> and
> > >
> > >>> most interesting part was, the 6809 Extended Basic still 
> > >>> functioned
> > >
> > >>> perfectly!  WOW!  So now the memory map is updated thusly:
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> $0000
> > >
> > >>>
> > >
> > >>>    |          40KB RAM
> > >
> > >>>
> > >
> > >>> $9FFF
> > >
> > >>>
> > >
> > >>> $A000
> > >
> > >>>
> > >
> > >>>     |          8KB I/O Space: MC68B50 ACIA chip is addressed 
> at
> > > $A000-$A001
> > >
> > >>> (Address Bus is not fully decoded.  The ACIA appears 
> throughout 
> > >>> the
> > >
> > >>> $A000-$BFFF address space.)
> > >
> > >>>
> > >
> > >>> $BFFF                                    MC68B21 PIA chip is 
> addressed
> > at
> > >
> > >>> $A004-$A007 (Address bus is definitely NOT fully decoded, yet. 
>  It
> > >
> > >>> appears everywhere.  Oops.)
> > >
> > >>>
> > >
> > >>> $C000
> > >
> > >>>
> > >
> > >>>     |          16KB EPROM programmed with 6809 Extended Basic
> beginning
> > > at
> > >
> > >>> $DB00.
> > >
> > >>>
> > >
> > >>> $FFFF
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> Although I can use the 6809 Extended Basic, I have yet to see 
> the
> > >
> > >>> power on boot up message.  I have to press reset a couple of 
> times
> > >
> > >>> before I see the OK message prompt.  Can Anyone tell me why?  
> I 
> > >>> think
> > >
> > >>> a capacitor is missing between the reset button and ground, 
> and if 
> > >>> so I
> > > need a value for the cap.
> > >
> > >>> I've tried several resister values a 100uf and 0.1uf capacitor 
> 
> > >>> values
> > >
> > >>> but nothing has worked so far regarding power on reset 
> working
> > >
> > >>> correctly.  The schematic for the initial version of Grant's 
> > >>> 6-chip
> > >
> > >>> 6809 computer is attached as a .png file.  This is the 
> schematic I
> > > started my project with.
> > >
> > >>> I will eventually be adding my additions to a new version of 
> the
> > > schematic.
> > >
> > >>> I'm just not sure yet what I'll use to draw the schematic 
> with.
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> I just received some more hook-up wire so I'll be fixing the
> > >
> > >>> addressing problem with the PIA.  After that, testing the PIA 
> chip
> > should
> > > be easy.
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> My next addition which I am in the middle of adding to my 
> 6809
> > >
> > >>> computer is a UM245R USB Prototype board from FTDI.  Since the 
> 
> > >>> FT245R
> > >
> > >>> chip is a ssop, they put it on a PCB with 24 legs so it will 
> fit 
> > >>> on a
> > >
> > >>> breadboard prototyping design layout just like a real 24-pin 
> chip.  
> > >>> I
> > >
> > >>> love it!  As soon as it is hooked up, I will be programming an 
> 
> > >>> eprom
> > >
> > >>> with the Simon6809 monitor
> > >
> > >>> program.   Simon6809 communicates with the host PC through - 
> you
> > guessed
> > > it
> > >
> > >>> - the USB port!  I can hardly wait to see that working!  You 
> can
> > >
> > >>> google "Simon6809" for further information if you're 
> interested.
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> That's all for now with the continuing saga of my Home Brewed 
> 6809
> > >
> > >>> computer.
> > >
> > >>> My little baby is growing.  It's so exciting!  Take care 
> everyone.
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> Kip
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>>
> > >
> > >>> --
> > >
> > >>> Coco mailing list
> > >
> > >>> <mailto:Coco at maltedmedia.com> Coco at maltedmedia.com
> > >
> > >>> <http://five.pairlist.net/mailman/listinfo/coco>
> > > http://five.pairlist.net/mailman/listinfo/coco
> > >
> > >>>
> > >
> > >> --
> > >
> > >> Coco mailing list
> > >
> > >> <mailto:Coco at maltedmedia.com> Coco at maltedmedia.com
> > >
> > >> <http://five.pairlist.net/mailman/listinfo/coco>
> > > http://five.pairlist.net/mailman/listinfo/coco
> > >
> > >>
> > >
> > >
> > >
> > > --
> > >
> > > <http://www.johnkent.com.au> http://www.johnkent.com.au
> > >
> > > <http://members.optusnet.com.au/jekent>
> > > http://members.optusnet.com.au/jekent
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > --
> > >
> > > Coco mailing list
> > >
> > > <mailto:Coco at maltedmedia.com> Coco at maltedmedia.com
> > >
> > > <http://five.pairlist.net/mailman/listinfo/coco>
> > > http://five.pairlist.net/mailman/listinfo/coco
> > >
> > >
> > >
> > >
> > > --
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> > > Coco at maltedmedia.com
> > > http://five.pairlist.net/mailman/listinfo/coco
> >
> > --
> > Coco mailing list
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> >
> 
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