[Coco] An FPGA GIME project, and CoCo FPGA Experimenter's Board

[David Ladd]

On Wed, Oct 21, 2015 at 8:28 PM, Zippster <zippster278 at gmail.com> wrote:

> Hi guys, these are a couple of cross posts from the Facebook group for
> people on the mailing list that don’t use Facebook.
> I’m planning another project to follow the MC6847 FPG VGA boards, and
> there’s been a little discussion over there.
>
>
> FPGA GIME PROJECT
>
> I've started doing some of the prep work for an FPGA GIME chip replacement
> project. This is a stepping stone toward a CoCo4 project.
>
> What I'm planning on is to develop a drop in board for the CoCo3 that will
> implement a GIME in FPGA, with 2MB of static RAM, and direct VGA out.
>
> I'll be using an Altera Cyclone IV FPGA for the project. Since more I/O
> pins will be needed than are available on Cyclone IV QFP packages, this is
> going to require me to use a BGA256 packaged FPGA and a four layer PCB.
> Toward this end I have a reflow oven on the way, and I'm entering the
> needed parts into Eagle. This will give us quite a few pins to work with in
> implementing new features later.
>
> This is going to be a very interesting and challenging project in several
> ways, but it's the big missing part of the puzzle hardware-wise to a fully
> CoCo3 compatible CoCo4, so hopefully it will be worth the effort.  :)
>

​Ed, I like this idea a lot.  Would be a good alternative to having the
RGB2VGA and as well be a future replacement for the GIME's since we can't
get new replacements anymore after the current stock runs out. :D  Plus I
love the idea of the built in static RAM too :D​



>
>
> COCO FPGA EXPERIMENTER’S BOARD
>
> As I've been entering parts preparing for the FPGA GIME project, I had an
> idea. With the work I'm having to do for that project, it would be
> relatively easy to develop an "FPGA Experimenter's Board" that would plug
> into the CoCo cartridge port along the way.
>
> Kind of an FPGA development board that could be used for interfacing
> projects. With an Altera device, some bi-directional level shifters, maybe
> an ADC chip, a couple of resistor DACs, and some other support circuitry,
> we could have a pretty cool board for people interested in CoCo/FPGA
> projects. Maybe help get some more hardware developed.  :)
>

​Well if this plugs into the CoCo's cartridge port and since it is also
FPGA, would one of the possibilities be​ to recreate a WD1773 floppy
controller chip on this as well?  Or even creating a real world version of
the becker interface on this device? :D  Just tossing out ideas :D



>
> Is there enough interest in something like this for me to pursue it on the
> way to doing the GIME replacement?
>

​Let me say oh hell yeah to the GIME replacement :D​



>
> What do you guys think?
>
>
> - Ed
>
>
>
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