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

[Joel Ewy]

A couple questions come to mind here:

1.  Does the CoCo care what kind of microcontroller is in the S/S Pak as
long as it does its job in the expected manner?  I wonder if one could
sub a PIC core (or maybe a 68-something) and then also make it a more
general-purpose I/O processor.  It could help out with faking a floppy
controller and who knows what other kinds of things.  One thing that
shouldn't be emulated is the S/S Pak's failure to run at 2MHz (and above!).
2.  How hard would it be to combine the Orch-90CC and the Speech/Sound
Pak?  I'm not real clear on how the S/S Pak is set up, or where the
dividing line is between analog and digital on it.  But surely an
amplifier is common to both, though the S/S Pak is perhaps just mono? 
Putting a stereo amp in the external hardware would just make sense. 
Now if the AY3-8913 produces a digital output, that can just be buffered
in one or both channels of the Orch-90, then out to the DAC in the
external hardware.  Otherwise, just add an analog mux in front of the
amp.  I don't know what addresses the S/S Pak uses, or what kind of
space might be left in its register mappings.  Might have to have some
virtual Multi-Pak action going on there.  Might have to improve the
address decode sections and provide a way to select which source has the
audio out bus.  That might require a one-liner to poke a register before
running a program, or a (virtual?) toggle switch for use with ROM Paks. 
But ideally one could make these things both work, so the CC-Five (or
whatever), could run just about any existing CoCo program that uses
sound hardware, whether synthesized or sampled.

JCE

Mark McDougall wrote:
> jdaggett at gate.net wrote:
>   
>> Now the Speech/Sound card module is a different critter. Unlike the
>> Orchestrra 90 card, which the main micro runs code from, the
>> speech/sound card has its own dedicated processor,  TMS7040. Along
>> with that is its own ram. The heart of the sound is the AY3-8913
>> sound chip, and the SP0256-ALS speech chip. I do believe there is a
>> HDL version of the sound chip available that maybe open source. The
>> speech chip may still be floating around in surplus markets.
>>     
>
> My colleague here has implemented the AY-3-8910 for our PACE project. It
> was reasonably trivial, if not a little resource-hungry. I understand
> that the 8913 is basically just 3x 8910 cores in one chip?!?
>
> I'd suspect that the SP0256-ALS isn't very difficult to emulate - AFAIK
> those speech chips where just wave tables...
>
>   
>> The TI micro is a 4 bit micro that is now obsolete. That along with
>> the sppech chip would be the hardest to reproduce. SO that kind of
>> forces backward compatiblilty with the current cards.
>>     
>
> That's a different kettle of fish, but still within the realm of
> possibility, I think. I'd love to do my own cut of a processor, for
> example, and maybe this 4-bit micro is a good candidate??? :)
>
> Regards,
> Mark
>
>