Re: Sound-makes only one click?

[!smentzer@ecom.net (Steve Mentzer)]

>8500:LDA $C036
>8502:JMP $8500

You are on the right track. But you are missing a couple of things.

#1 - Sound is produced on the a2 speaker by peeking and poking at the speaker 
port repeatedly. Different rates of "reading/writing" will vary the tone.

#2 - I think you need to do a STA $CO36 as well. If I remember correctly, 
reading pushed the speaker cone out, while storing a value retracted the 
speaker cone. I could be wrong (and I propably am).

#3 - Doing a tight loop like the one above will only yield tones that a dog 
might be able to hear. remember that your computer operates at 1Mhz. 
Discounting overhead issues, the above code would cycle 250,000 times a second 
(assuming LDA and JMP [direct] consume 2 cycles each, which may be wrong). That 
is 250khz, which to my knowledge is MUCH beyond the range of human hearing.

	doing something like this might work 

	(improvising assembly code...hehe... its been a LONG time)




	(calling routine)

	STX	#80 		(push decimal 128 onto the X register, 				 
				 frequency delay value)

	JSR	_SpeakerOut	(call the speaker out routine)
	BRK

	(speaker output)

	_SpeakerOut

		TXA	(transfer X reg to the accumulator)
		LDA	$C036
		STA	$C036

	_SpeakerOutLoop

		DEC				(decrement the accumulator)
		CMP	#00			(have we decremented to 0?)
		BNE	_SpeakerOutLoop		(if not, delay some more)
		JMP	_SpeakerOut		(click the speaker again).


Hope this helps....

:)

smentzer@ecom.net
		
		
		
	

		


But you need to remember that "reading" a value