Hi all,

i'm one of the thirty-something guys who used to have an MSX-1 (Sony with 16k)
and even then I was already very interested in the sound-command.
Unfortunately after 20 years I forgot all of it and i don't have the machine nor
the books anymore.

I used to have a program on tape from a zine, this program showed a screenfull
of parameters to tweak for the soundchip. it was like playing with an analogue synthesizer , only without the keys

Does anyone have a good guide on the Sound command (NOT using the special
sound cards like SCC or MSX Audio)
When I try to use it i mostly get "illegal function call"s.

I tried "googling" it but it's a dead end. most of it is related to the soundcard extentions.
or in Assembly and not comprehensive enough.

Thanks!

The SOUND command directly sets a value into a PSG register.
Basic syntax for the SOUND command is

SOUND <register>,<value>

Where <register> is in the range of 0 upto 15 and <value> is in the range of 0 upto 255.
The Wikipedia page for the PSG contins a lot of links to resources for your reading pleasure.
Happy MSX-ing!

(sorry, /me too lazy to write a complete PSG tutorial right now )

Thanks! this is one step closer, i'll just have to pick my own technical brain and
see what I can come up with.

cheers!

Get the PSG doc at http://www.robsy.net/ay38910.pdf or check the PSG part of the excellent MSX Red Book, that you can grab at http://www.robsy.net/tredbook.txt

Of course, I'm afraid it is not very straightforward.

You can also download SEE (from here). It's basically a front-end to the PSG registers with a few extra commands. Useful to help get a feel for it.

The play command is really easy to use.
Play "abc" will do just that!

Edwin, the SEE program doesn't seem to work on BlueMSX, i get a good logo but the tekst display
is scrambled. trying to tweak the settings of BlueMSX but no luck.

Anyway, for the moment i'm looking for assembly code to make a sinus wave, then gimme 2 more years to make a synth with LFO and arpegiator

thanks all again for the information. hope to come back soon with some more "geekyfreaky" questions...

Try this version :

http://www.thefuzz.nl/msx/files/apps/utils/see3B.rar

Try to find another version, iirc one of the SEE versions was made on a sunday-morning after Ro tried to break the national boozing-record..

[edit] arf ^_^

SEE is a bit tricky. You have to start it from 80 column mode, otherwise the screen gets messed up.

That's not "a bit tricky", that's sloppy programming

isn't there a PSG register bit you're not supposed to change? does the SOUND command have a safeguard for that (I hope)?

Quote:

isn't there a PSG register bit you're not supposed to change? does the SOUND command have a safeguard for that (I hope)?

Register 14 and 15 are better left untouched. These two registers control the joystick ports.
The two most significant bits of register 7 should always be 10 (so reg 7 has a value of 10xx xxxx).
The two bits of reg 7 specify how the registers 14 and 15 are used.

SOUND 14,x or SOUND 15,x gives an illegal function call, but there's no safegueard against putting wrong values into register 7.
And apparently it is possible to damage hardware when writing values other than 10xx xxxx to register 7

Quote:

isn't there a PSG register bit you're not supposed to change? does the SOUND command have a safeguard for that (I hope)?

You mean two most high bits of register 7. They should always be %10. When using sound command, these bits will be set automatically to %10.

Yes , i read that part about the register mandatory settings.
but after reviewing the specs I think my biggest concern is adding modulation to the tuning...
every time the value changes, the adsr will be retriggered i think and that's not what i need...
i'll have to test it out....


Another thing, are there any binary files available with pre-calculated sinus-values
to create an LFO ? (low freq osc)

Creating a math routine is just ridiculous...what was i thinking !