[Coco] Re: Coco Repack
jdaggett at gate.net
jdaggett at gate.net
Sat Aug 7 14:27:21 EDT 2004
Kevin
Page size is alterable, but then the software, especially OS 9, is no
longer compatible. The thought of 16K pages and four tasks runing
would be nice at 4MBytes of ram. Personally I would not care to tink
of that kind of rewrite.
Besides if yo uneed more memory a virtual memory driver and a
hard disk or MM card will give you all the memory you need.
james
On 7 Aug 2004 at 9:03, Kevin Diggs wrote:
Date sent: Sat, 07 Aug 2004 09:03:28 -0700
From: Kevin Diggs <kevdig at hypersurf.com>
To: CoCoList for Color Computer Enthusiasts
<coco at maltedmedia.com>
Subject: Re: [Coco] Re: Coco Repack
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> James,
>
> What about altering the page size? What are your thoughts?
>
> kevin
>
> jdaggett at gate.net wrote:
> >
> > Mark
> >
> > The MMU is real simple. It is basically a 2 to 1 4 bit wide
> > multiplexor that feeds a 16x8 ram. The GIME chip uses a 16x6 ram.
> > Most likely the package was limited to 68 pins by Tandy and cost
> > factors. Next standard size up is 84 pins in a PLCC package. Given
> > that during the 80's it was around 10 cents a pin for package cost,
> > another 16 pins would have meant another $1.60 for the part.
> >
> > I really believe that many of the limitations of the GIME chip is
> > solely due to keeping costs to a bare minimum.
> >
> > The VGA portion is tough to code and will occ py the most territory.
> > That will determine how big the FPGA is and how much any project
> > like th is will eventually cost. Most of the free VGA cores are more
> > modern and do not cover CGA resolutions. Or they are very generic
> > and need more work to make them compatible to 8 bit buss. One of the
> > nice things is that the software to design the logic and program the
> > FPGA is free. Right now I am designing the logic for the two
> > registers at $FF92/3. These registers do a dual purpose. They enable
> > interrputs and also act as interrupt flags. When you read the
> > register, the flags are cleared while the interrupt remains enabled.
> > Not a simple D-FlipFlop latch. Most of the rest of the registers are
> > just that, D flipflop latches.
> >
> > Then there will be the 2 to 1 (21) bit wide multiplexor to switch
> > between video memory and program/data memory. The hardest part is
> > keeping remebering that the 6809 latches data out of the CPU on the
> > falling edge of the Qclk and latches data in to the CPU on the
> > falling edge of the Eclk. Have to keep in mind when the data needs
> > to be presented to the CPU and when the CPU is passign data to
> > external devices. After all that the first half of the Eclk cycle is
> > doing display.
> >
> > Mark, like I stated in the beginning, I got started with this to use
> > the Coco as a postion controller and database for my telescopes. One
> > thing that I wanted was to be able to drive an LCD panel of some
> > type and have OS9 boot from a flash card or flash memory. I wanted
> > at least 2 megs of sram and not dram. IDE interface and at least 4
> > mbytes of flash for storage.
> >
> > Real pipe dreams was to add firewire or USB and a parallel port to
> > control a CCD camera for astronomy.
> >
> > So this will start as a home project and I have no idea of where it
> > will go. I have toyed with the thought of a FPGA version of the
> > 6309 and run it at say around 15 to 25 MHz. These are future t hings
> > to work on. I am right now having fun with it and learning VHDl in
> > the same time frame. It is amazing what you can do with CPLDs and
> > FPGAs. Some of the software development boards that I designed years
> > ago would be more flexable and easier had I done a lot of the simple
> > glue logic in these devices.
> >
> > james
> >
> >
> > On 6 Aug 2004 at 18:27, Mark Marlette wrote:
> >
> > Date sent: Fri, 06 Aug 2004 18:27:21 -0500
> > To: CoCoList for Color Computer Enthusiasts
> > <coco at maltedmedia.com> From: Mark Marlette
> > <mmarlett at isd.net> Subject: Re: [Coco] Re: Coco
> > Repack Send reply to: CoCoList for Color Computer
> > Enthusiasts <coco at maltedmedia.com>
> > <mailto:coco-
> > request at maltedmedia.com?subject=unsubscribe>
> > <mailto:coco-
> > request at maltedmedia.com?subject=subscribe>
> >
> > > At 10:45 PM 8/6/2004 +0000, you wrote:
> > >
> > > The 63B09 = 2MHZ, 63C09=3MHZ and 63D09=4MHZ.
> > >
> > > James has quite a project just to do the GIME in a FPGA. Lets not
> > > overwhelm the project and make it not happen. The paragraph below
> > > is a HUGE task! Remember this is a hobby for most. To do the
> > > software, hardware and test takes quite some time. Better yet how
> > > many people would step forward and help out on it? How about put
> > > up the $$$ to buy one????? I have over $5k out on the SuperBoard
> > > project, that doesn't include my time. Love of the machine or
> > > stupidity...... :)
> > >
> > > It is quite a simple task to make the memory map for the GIME, it
> > > is ALOT harder to perform all of the functions that is behind each
> > > bit. The MMU is simple as well. Interrupt and timer functions are
> > > a bit more complex and not documented the best. The video with all
> > > the compatibility modes is something else as well. No doubt
> > > something to be proud of, the GIME is the machine. I have been in
> > > direct contact with the creators of this beast and it is AMAZING
> > > to me that nobody has an internal document of it. I also do
> > > believe if they had it, I would have it as our conversations went.
> > >
> > > Mark
> > > Cloud-9
> > >
> > >
> > > >IIIRC the 6309 is a 4 MHz part? I doubt it will run reliably
> > > >after 6-8 MHz. Even then, it could vary between chips. If you put
> > > >a 6309 in FPGA you could drop some of the 6809 compatibility and
> > > >possibly put in some new code, but then you'd lose program
> > > >compatibility. Not sure how much that would affect NitrOS9 for
> > > >the 6309 though. Still, if you do a CoCo repack with the joystick
> > > >ports and replace the bit banger with USB (or two...), it would
> > > >be a nice system. Wouldn't be 100% CoCo compatible once the ROMs
> > > >were in place, but would be close. Would be very nice if the DECB
> > > >ROM could be modified to use a USB floppy, and maybe HD. But DECB
> > > >really doesn't need a HD for experimental purposes. Some sort of
> > > >mass storage would be needed, maybe one of those USB "drives"
> > > >would be easier to code in the ROM, but you'd have to transfer
> > > >code from a PC to run DECB programs. The only reason I harp on
> > > >DECB is the ease of programming for experiments. Basic09 is more
> > > >powerful, it has similarities t
> > > > o Pascal, but CoCo BASIC is so darned easy to learn that for
> > > > simple
> > > >
> > > > and/or quick experiments it would be preferred.
> > > >
> > > >
> > > >--
> > > >Frank Swygert
> > > >Publisher, "American Independent
> > > >Magazine" (AIM)
> > > >*Elite* publication for those
> > > >interested in all
> > > >aspects of AMC
> > > >history,performance,restoration,etc
> > > >.
> > > >(AMC,Rambler,Nash,Hudson,Jeep,etc.)
> > > >http:farna.home.att.net/AIM.html
> > > >(free download available!)
> > > >
> > > >
> > > >
> > > >-------------- Original message from
> > > >coco-request at maltedmedia.com: --------------
> > > >
> > > > > Message: 3
> > > > > Date: Fri, 06 Aug 2004 11:30:48 -0400
> > > > > From: jdaggett at gate.net
> > > > > Subject: Re: [Coco] Re: Coco Repack
> > > > > To: CoCoList for Color Computer Enthusiasts
> > > > > Message-ID: <41136BE8.14904.E66F7 at localhost>
> > > > > Content-Type: text/plain; charset=US-ASCII
> > > > >
> > > > > Frank
> > > > >
> > > > > You are ringt if a FPGA version of the 6x09 were incorporated
> > > > > along with an FPGA version of the GIME chip, breaking the 10
> > > > > MHz barrier will be no problem. Speed control can be done with
> > > > > external clock ship. One by ICT can derive 1000's of
> > > > > frequencies from a single crystal frequency. In fact the one
> > > > > chip that I was looking at, from a 28.6868 MHz cyrstal I can
> > > > > derive over a 1000 different E and Q Clocks for the CPU from
> > > > > 400 KHz to 19 MHz.
> > > > >
> > > > > My initial intent was to use a 6309 and my new GIME chip and j
> > > > > ust see how fast I can over clock the 6309. I have two bytes
> > > > > resevered in the memory map to address the clock PLL chip.
> > > > >
> > > > > Just keep pushing the clock until the chip stops.
> > > > >
> > > > > james
> > > >
> > > >--
> > > >Coco mailing list
> > > >Coco at maltedmedia.com
> > > >http://five.pairlist.net/mailman/listinfo/coco
> > >
> > >
> > >
> > > --
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> > > http://five.pairlist.net/mailman/listinfo/coco
> >
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