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Re: Very basic sound programming question
On 2009-03-31, schmidtd <schmidtd@my-deja.com> wrote:
> On Mar 31, 5:10�am, Jim <j...@magrathea.plus.com> wrote:
>> On 2009-03-31, Jim <j...@magrathea.plus.com> wrote:
>>
>> [snip]
>>
>> Actually, hold off on that - I just discovered the sitehttp://8bitsoundandfury.ld8.org/programming.htmlwhich seems to have what I
>> need. From that site:
>> ----------
>> Not sure where this came from so I can't properly credit it, though I'm sure
>> I'm not giving away any trade secrets by publishing it here. Basically this
>> just pokes in a Machine Language tone generator from AppleSoft which can, in
>> turn, be called from the same AppleSoft program:
>>
>> 10 FOR L = 770 TO 790: READ V: POKE L,V: NEXT L
>> 20 DATA 173,48,192,136,208,5,206,1,3,240,9
>> 30 DATA 202,208,245,174,0,3,76,2,3,96
>>
>> Now we have the tone generating routine in memory all we have to do is tell
>> it what note to play and for how long. This is done like so:
>>
>> 40 POKE 768,F: POKE 769,D
>
> One critical piece of information seems to be missing... how to
> actually trigger the sound! You can do that with:
> 50 CALL 770
[laugh1] yes, that hadn't occurerd to me! Thank you.
>
> I played a low then high "C" with this:
>
> 10 FOR L = 770 TO 790: READ V: POKE L,V: NEXT L
> 20 DATA 173,48,192,136,208,5,206,1,3,240,9
> 30 DATA 202,208,245,174,0,3,76,2,3,96
> 40 F1 = 255 : D1 = 75 : REM LOW C
> 50 F2 = 64 : D2 = 50 : REM HIGH C
> 60 POKE 768,F1: POKE 769,D1 : CALL 770
> 70 POKE 768,F2: POKE 769,D2 : CALL 770
>
Out of interest is there any way to control volume?
Jim
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