[Coco] Faster CoCo for George... Was: Re: OT: Gramical nitpiking >My CC3>CC4

[Joel Ewy]

George Ramsower wrote:
>
> ----- Original Message ----- From: "Joel Ewy"
>> George Ramsower wrote:
>>> ...
>>> I would be tickled pink to have a 20mhz CC3 that would use my existing
>>> hardware. I can easily get another keyboard and monitor. However, I
>>> cannot easily replace all the stuff that plugs into a coco and the
>>> software I've developed for it.
>>> My CNC stuff would work faster and better also!
>>>
>>> This is selfish of me, I know.
>>>
>>>  I want MORE in a coco.
>>>
>>> More speed!
>>>
>>> Just simply.... more SPEED!
>>>
>>
>> George, If you haven't already noticed Gary Becker's latest FPGA CoCo 3
>> announcement in this list, you might want to take a look.  It appears
>> after a first glance through the documentation that there is no CoCo
>> compatible hardware expansion bus implemented in this design, so hooking
>> your custom CNC motor controllers up to this beast may not be possible
>> without some further work.  But it does run at about 20MHz, and the
>> design is open.  So even if you don't feel like learning how to modify
>> the design to do what you want, hooking up real CoCo peripherals to the
>> FPGA board is likely to be something that many other users would want to
>> do, so it may well be something that others will work on for you.  It is
>> at exactly this point that James Jones will chime in and remind us that
>> many FPGAs don't play nice with 5V logic.  :)  So making a CoCo
>> expansion bus for this design may turn out to be non-trivial.  Still,
>> this is a major step in the right direction towards a faster and more
>> capable CoCo for the future.
>>
>
> Would this sort of thing require a "Wait State" for the slower
> peripherals such as floppy controllers, RS232 cards and the like? 

Yeah.  I think that any CoCo compatible bus interface built for an FPGA
CoCo would have to have a 1-2MHz E clock.  But if you could use
interrupt-driven drivers your CPU could still be chugging away most of
the time and wouldn't have to wait too long too often for the slow
peripherals, at least under OS-9.

> Even my CNC stuff would be too slow, I think. However, I bet there are
> faster 74xxx chips out there that could replace the ones I'm using in
> my I/O board that connects to just about everything I do on that coco.
> It's just an address decoder with four input buffer chips and four
> output latches. Lately I've been thinking of adding more because, I
> may need more as this project continues.
> As with any computer project, the need for speed, memory and more
> speed increases with progress.
> I'm thinking a binary up/down counter on the stepper motor drivers
> would give me a REAL indication of their positions and any errors in
> math that may put them in the wrong place can be corrected on the fly,
> giving more reliable accuracy over the long haul.
> Of course, this will require more coding, more CPU time and thusly
> requiring more speed. Ugh.
>
Another thought for you might be to try Sockmaster's "4MHz" upgrade.

JCE

> George
>
>
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