[Coco] COCO FPGA

Aaron Wolfe aawolfe at gmail.com
Sat Dec 24 03:43:15 EST 2011


On Sat, Dec 24, 2011 at 3:19 AM, Mark McDougall <msmcdoug at iinet.net.au> wrote:
> On 24/12/2011 3:38 AM, Aaron Wolfe wrote:
>
>> As for hardware like the Speech/Sound pak, don't forget that these can
>> be implemented right in the FPGA.   While the FGPA boards do provide
>> I/O pins for interfacing with add on hardware, there isn't always a
>> need to build it when FPGAs are so flexible and powerful.
>
>
> The reason the Speech Pak hasn't been emulated in an FPGA is because it has
> (IIRC) a processor, so someone would have to first develop and debug that
> core before the rest of the pak - which shouldn't be very difficult - could
> be done.
>

Yes, its a fairly common sound chip from that time period iirc though
I forget the model.. might be someone already has implemented it for
some other project.  There might not be room in the boards we are
using now for it, not sure.  FPGAs get more powerful and cheaper like
everything else though... someday soon I don't think there would be
any hardware that exists for the "real" CoCo that can't be recreated
in fpga, and at that point you're just left dealing with the actual
connectors and interfaces to the outside world... not trivial but
probably a lot less work than actually connecting the original
hardware.  For instance Gary made a small board that allows connection
of joysticks and provides an rs232 pak or bitbanger, but I don't think
the board actually contains a PIA or a 6551.. its just the electrical
interface needed to get the signals into the FPGA where the actual
hardware is implemented.  When you think about it, there are few
actual connectors are needed that aren't already there.  Audio is on
board, so anything that produces sound is covered.  Video is there,
the joysticks and serial ports are there.. whats left, cassette input?
 If we find a way to provide all the connections, I think the rest
being done in the FPGA makes a lot of sense.  We might not be quite at
the point where you can fit *everything* ever made for the coco
hardware wise into the current cheap boards, but we aren't far from
at.



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