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

[jdaggett at gate.net]

On 25 Jan 2007 at 9:41, Mark McDougall wrote:

> I'm not familiar with the technical specs of the Orchestra-90, but I'm
> assuming it has some commonly-available (at the time) FM synthesizer
> chip in it?!? Whether that would be considered as 'adequate' for the
> Coco 4/5, I can't say. But there would also be the option of
> including, say, the Apple IIe "Mocking Board", which uses two sound
> chips found in plenty of arcade games of the era.

*************

Mark 

the heart of the Orchestrta 90 card is the 8Kx8 rom program. Hardware wise there 
would be a minimal resources for an FPGA. Two 8 bit adressable latches with 
decode lagic for address mapping. 

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. 

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. 

james