[sdiy] My New Project - PCSYNTH

[Scott Gravenhorst]

=?ISO-8859-1?Q?Johannes_=D6berg?= <johannes.oberg at gmail.com> wrote:
>You call building an ISA card from scratch simple, but vanilla DMA
>programming wouldn't be?! What is difficult about using the DMA on a
>regular soundcard? Or is >44 khz output necessary?

I have considered > 44KHz.  Aside from that, it's a completely different
approach.  Instead of the simple "create a value then present the value to
the DAC", you have to compute a buffer full of values set up the DMA
transfer and tell it to go, switch buffer areas, make more values, and wait
for an interrupt.  Yes, it's possible.  No it's not the way I prefer to do
this.  And yes, in my opinion, for me, the building of a DIY ISA DAC card
would be easier.

>
>I would suggest you start writing the software with the hardware
>you've got (even if it's a lowly sound blaster), and if the results
>don't please you, then build the sound interface. The sound routines
>module will only be a very small part of the program and could be
>easily changed when you have the rest of the program working.

The hardware I have has really slow I/O.  It will work, but half of the
computation time will be absorbed in accessing the DAC if I use the LPT
method.  

This is not meant as a one off project.  This is meant for me, but also to
share with others (which is why I'm posting this here in the first place).
 While writing the DMA routine for one card (mine) might be something I
could do, I don't want to repeat the process for other cards that other
people use (there's probably a good reason why there are many sound card
drivers, i.e., they don't all work the same).  however, if I publish an
interface schematic, anyone can build it and the chances of someone else
making this work will be better.

>That said, good luck, I would very much like to see any result you
>come up with, especially since I have tons of old computers lying
>around.
>
>/J
>
>>Scott Gravenhorst wrote:
>>That's one way to do it.  I prefer not to use DMA.  I want _simple_.
>>
>>I really like Roman's idea of hacking off and using the edge connector of
>>a defunct ISA card... [snip]
>

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