[Coco] CC-Five (was Re: Pseudo CoCo4???) (LONG)

[Joel Ewy]

jdaggett at gate.net wrote:
> In doing that  you may limit the hardware or cause an increase in cost for 
> hardware to be backward compatible. 
>
> Just about anything now to go into a FPGA will require extra hardware to 
> interface 3 volt logic to 5 volt logic.
>
> james
>
>   
Hmm.  How difficult a chore would that be?  What if you didn't bother
with designing the board that has the FPGA on it at all and simply
planned to use off-the-shelf FPGA prototyping or evaluation boards. 
Design a CoCo personality board that would have the bus and peripheral
connectors on it, and the DRAM sockets, and the A/D converters, and all
the stuff that wouldn't be found on the FPGA boards.  Include the logic
level conversion on that board and try to design for the future, so that
upgrading would mean replacing only the FPGA board.  Is the logic level
conversion intrinsically difficult/expensive, or is it just another
design consideration?

JCE
> On 22 Jan 2007 at 9:39, Joel Ewy wrote:
>
>   
>> I think there would need to be a sufficient level of backwards
>> compatibility that people would have software to run on the new
>> platform while developing the new stuff.  This also means that much of
>> what now exists in software could just be enhanced rather than being
>> entirely rewritten from scratch.  This is also why I'm suggesting
>> modest, attainable improvements over the CoCo 3.  If a next-gen CoCo
>> has better built-in sound, then build in an Orch-90cc circuit, so that
>> one could run software that already uses that hardware.  Here's where
>> emulators and real hardware could work synergistically.  If the
>> emulator is free, or very inexpensive, then lots of people can quickly
>> get their hands on the new system and write new software, so that
>> there will be something to run on the real hardware.
>>     
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