[Coco] How Many OR90s can be utilized?

RETRO Innovations go4retro at go4retro.com
Sat Nov 12 13:59:05 EST 2016

On 11/12/2016 9:08 AM, Barry Nelson wrote:
> 1) ORC90s are not controlled by the SCS line as their default address is not within the SCS range, so their address would conflict, even with a multi-pak.
Original OR90's, yes.  CocoFLASH OR90 engine: not true.
> 2) No software has been written to use an ORC90 at any alternate address.
Understood. But, there's no requirement that the OR90 be at a different 
address.  You can also selectively "hide" an OR90 in the memory map.
> 3) What would you do with it?
One of the hallmarks of the classic computing crowd (at least some of 
them, anyway), is to push the system beyond the original plans. The 
Coco3 supports 512kB of RAM, but I know 2MB expansions were available.  
Dual UARTs, Drivewire, Glenside IDE/SuperIDE, etc. show the people 
always want to stretch the capability of the machine.

Thus, people expect the same expansion capability in new hardware 
designs.  It's the philosophical foundation of these communities.

So, providing a replacement OR90 is the bare minimum capability to be 
offered, but the community really expects more.  The Tandy has a MPI, so 
it is conceivable that at least 4 units could be installed. Someone, 
somewhere, will try to do that, mainly to see if it can be done.  We 
already know it will work, since the *CART line is mulitplexed.  So, the 
first unit comes up, runs an app, and the app relocates all of the other 
CocoFLASH carts so they do not conflict on register space.

At that point, someone is going to say.... "Hey, I wonder if I can write 
some code to drive all 4 sets of OR90 engines."

Though 4 might be beyond the CPU bandwidth capabilities, if 2 can be 
done, someone out there is going to be disappointed if I don't support it.

They'll say things like "Man, he had a CPLD there, and it would have 
been trivial to add support...  What a waste that he didn't."

Also, consider the individual who says "I don't care about multi OR90s, 
but I want to use my original Orch90, and your cart conflicts with it.  
Bad Jim, Bad!"

So, I am trying to ensure both situations are non-issues.

I can also see Zippster producing a batch of Orch90 carts, and someone 
wanting to run one of those with CocoFLASH, using both at the same 
time.  If Zippster has some extra space in his CPLD, it's a small item 
to add the capability.

I also see it as incongruous to offer a ROM cart that has lots of 
flexibility, alongside an OR90 capability that has no flexibility...

To answer your question, it seems reasonable that someone would want to 
attempt quadraphonic sounds using 2+ units.  I think TANDY already 
offered the SOUND/SPEECH pak and the ORCH90 pak in different IO 
addresses assuming someone would pair them for some use.

The difficult part here:  Once the devices leave my hands, it will be 
difficult to add features.  So, I have to add them now, before they are 
utilized.  Thus, I am trying to think ahead, to see if it is reasonable 
to expect someone will want the capability.

To my original question:  Anyone know how heavily the CPU is loaded when 
playing OR90 samples?


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