[Coco] Orchestra 90CC

[Bob Devries]

Joel, I suspect that there are some set data rates for sound cards, such as 
44KHz, 22KHz etc. If the FGPA's FIFO could be set up to take the data as 
fast as possible, and then output it at that rate, it would work in a 
similar way to the PC sound card. However, I have no idea what the data rate 
for the Orchestra-90 is.

I wonder if those people who wrote OS9 drivers for the Orchestra-90 would 
know/divulge this?

--
Regards, Bob Devries, Dalby, Queensland, Australia

Isaiah 50:4 The sovereign Lord has given me
the capacity to be his spokesman,
so that I know how to help the weary.

website: http://www.home.gil.com.au/~bdevasl
my blog: http://bdevries.invigorated.org/

----- Original Message ----- 
From: "Joel Ewy" <jcewy at swbell.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Monday, January 29, 2007 3:35 PM
Subject: Re: [Coco] Orchestra 90CC


> Bob Devries wrote:
>> James,
>> While it's true that the ROM in the Orchestra-90 does do what you 
>> describe,
>> any third-party and OS9 software does its own handling of the data,
>> including the timing between the sending of the data to the ports.
>>
>>
> Right.
>> So unless the new hardware has some way of knowing how much time to 
>> insert
>> between "packets" of 2-byte stereo pairs, indeed the FIFO will make no
>> difference. In fact, I'd rather think that it would completely screw up 
>> the
>> timing that's necessary for the Orch-90 to work correctly.
>>
>>
> And that's what Kevin's original post said.  See below.
> So how are such things done on PC sound cards?  Is there some logic for
> pushing the data out at a defined sample rate, or is it all done in
> software?
>> --
>> Regards, Bob Devries, Dalby, Queensland, Australia
>>
>> Isaiah 50:4 The sovereign Lord has given me
>> the capacity to be his spokesman,
>> so that I know how to help the weary.
>>
>> website: http://www.home.gil.com.au/~bdevasl
>> my blog: http://bdevries.invigorated.org/
>>
>> ----- Original Message ----- 
>> From: <jdaggett at gate.net>
>> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
>> Sent: Monday, January 29, 2007 6:42 AM
>> Subject: Re: [Coco] Orchestra 90CC
>>
>>
>>
>>> Kevin
>>>
>>> Adding a FIFO would do nothing to improve the performance. Audio tones 
>>> are
>>> genereated via the software in the 8Kx8 ROM. All the uP does is write to
>>> two
>>> addresses an eight bit data. The writes are to two 8 bit latches whose
>>> outputs
>>> have a 2R:R resistor ladder to perform digital to analog conversion.
>>>
>>> The way the progrma works the best method of improvement is to run the 
>>> uP
>>> at a
>>> faster speed. Then the software would need patching for timing issues.
>>>
>>> james
>>>
>>> On 27 Jan 2007 at 20:20, Kevin Diggs wrote:
>>>
>>>
>>>>  With all the recent discussion of the 90cc, I thought I'd ask:
>>>>
>>>> If this thing had had a FIFO <b>and some logic to send samples out at
>>>> regular intervals</b> how much would that have aided performance? To 
>>>> ask
>>>> another way, how much of a burden was it that the 6809 not only had to
>>>> compute the samples but also had to deal with sending them out at the
>>>> right time?
>>>>
>>>>
> (Emphasis added, JCE)
>>>> kevin
>>>>
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>>>
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>>
>>
>>
>
>
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