Re: SFX Expander programming and VICE

Hi,

On Wed, Nov 30, 2011 at 02:22:22AM -0800, davidt wrote:
> Hello all
> 
> Interesting discussion and subject.
> I'm working on something related to this, I want to use an SFX Sound
> Expander as a stand alone synth, with buttons, knobs and all that stuff.
> In the longer term, it would be great if something new could be written for
> the C64, as lets face it, the software is a bit basic and crude.

Meanwhile, I've started to write an S3M (module format of Scream Tracker 3
from Future Crew) player, since it has AdLib abilities (not only digital
samples can be used).  Currently it decodes S3M files (patterns are
compressed with a simple algorithm; I dedocde it on-playback since full
one-time unpacking would need just too much memory for a C64), and there is
display of "playback" (however it does not handle pattern commands,
tempo/speed setting etc - so it's not so much useful for real), however no
sound yet :) Also it's a bit hard to test, as I have no SFX Sound Expander
cartridge (yet?) and VICE seems does not work for me to emulate it (it has
no sound - as I've written in a previous mail).  I even have the odd idea to
map the 9 (melody - no info about the "drum" channels) AdLib channels to 3
SID channels (with rapidly chaning between the 9 from an IRQ handler) so I
can hear something at least if it works :-P Of course this sound
"experience" will be awful :)

Maybe that software (if I ever "finish" it at least for a state that it's
not laughable - then I would release it with source code) can be expanded to
even have some editing interface - it means a simple S3M Adlib tracker for
C64, which can produce files playable on PC too (like with Scream Tracker
III itself) in theory at least ...

Unfortunately:

1. I am not expereinced with module player codes, especially I have problems
   with interpreting the commands used in the patterns; it's hard to get
   any information on this topic
2. Again - I have no cartridge to test, nor the emulator (vice) can do it
   for me ... It's interesting, since I've tried the windows version of
   vice 2.3 running with wine 'windows emulator' (I have no windows at all),
   but it also cause "signal 11" and similar things ...

> I got that program working in Vice, no problem at all, except rename it to a
> .prg from a .txt, haven't tried it on a real C64 yet, maybe later today.

Do you mean about my DRO player now?  Sorry, I am a bit confused now, as you
replied in the thread at Z80 CP/M cartridge, so I am not sure which software
(and topic ...) you mean.

> I own 4 of these carts and three full sized keyboards so am familiar with

Arghhh, and I have zero of those! Have you any odd ideas to donate one for
me? :)

> the "something your wife wants to throw away" thing.  This just motivates me
> more to complete what I've started.
> The price of these things has risen over the last couple of years, but they
> are quite common still.

Hmm, I have never seen anything like this for sale, but it's true that I
haven't tried to find one too much, just browsing "retro computing stuffs"
from time to time just for fun.

> It is correct that they came with a 3256.  One of my 4 carts is a bit
> crunchy in sound so did look at replacing the chip with a 3812. But at the
> moment that one is used for testing and development.
> 
> There is plenty of documentation for the device and most of the parts are
> still obtainable, so a DIY clone shouldn't be too hard to build.  I am more
> of a hardware person, so if anyone needs some help on this I'd be happy to
> oblige.

Well, as I've written, I am thinking to get a 8 bit ISA card (AdLib, or an
early SoundBlaster which have 3812 and AdLib compatibility as well).
According to this: http://www.raphnet.net/electronique/adlib/adlib_en.php
it would be not hard to interface with a C64 (instead of PC paralell port
what that article is about). For sure, the "keyboard" part won't be
implemented, but enough to produce sound with softwares written for
the cartridge, at least I guess so.

My motivation is exactly the price, even some dozens of dollars is useful
for our family currently nowdays :( So for my hobby I can do only what I can
build with tons of spare things stored at my parents' house ... :)

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