[A89] Re: link port and sound (Was: Re: Re: Yikes! A major problem!)
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[A89] Re: link port and sound (Was: Re: Re: Yikes! A major problem!)
At 09:17 2001-03-31, you wrote:
>Olle, I've been meaning to ask you if there was a way to connect the 3.5mm
>jack directly to memory or another place on the board so it would be
>possible to have a program use the link port and sound simultaneously. A
>good example would be a 2-player linked tetris game while sound is playing.
>
>Any thoughts?
It is ofcourse possible, but I do not know of any simple way to do it. Like
two pins just lying around ready to connect to. Maybe you can find
something on a HW2 calc, but I doubt it.
But you can always put a latch on the databus though (2bits are enough,
ignoring the higher 14 bits of data), and use some logic to generate a
chipselect from the adress bus at some free memoryadress. And check R/W and
odd/even CE ofcourse.
Then you'll probably need some drive circuit for the port, so it is strong
enough to pull the pins to the loudspeaker.
two transistors or something.
Not extremely advanced, but not very simple either. If you havn't thought
of this option yourself, I don't recommend trying it :)
Involves a bit of tricky soldering, and knowledge about microprocessor
technology and digital electronics in general is a must.
Another far out though for this, is this; Design the protocoll for
communication between the calcs, so there is a corelation between the sound
playing and what information you want to send to the other side. Then just
connect both the loudspeaker and the link to the port, and hear them
communicate, disguised to music.
Probably even trickier then building another linkport though, but it would
be cool. :)
///Olle
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