Re: [PARPORT] Two or more interrupt-driven devices?

Lijun Zhu (lzhu@Bayou.UH.EDU)
Fri, 12 Mar 1999 16:18:49 -0600

Thanks a lot! Mr. David Campbell and Mr. Matthias Jim Knopf!

Maybe I think my ideas are basically the same:
1) Read from some inut port(let this process sleep because I only have
to deal with them when buttons are pressed);
2) When any button is pressed, in interrupt is generated to wake up the
read process, reading infos of which button is pressed and then, I can
deal with the correspong functions.
So according to this, maybe I have to connect each button both to the
pin that can generate interrupt and another which can be read as info
of which button is pressed. Thus I have to make a complex structure of
outside buttons(maybe I have to set up some gates avoiding their

I wonder whether whether there's a much easier structure.

Matthias Jim Knopf wrote:
> Hi!
> > Recently I succesfully designed a program that could use parport ( connect
> > a pushbutton to Pin 10) as a method to generate an interrupt to wake up some
> > process. But, now I need more pushbuttons to wake up different processes,
> > while there is only one pin of parport I can connect. How to deal with
> > other buttons? The way I think can be
> > 1) Using bi-direction method, I can read info about which button is
> > pressed by reading from the data port after the interrupt is generated(of
> > course I have to connect each button both to pin 10 and one data port).
> > 2) Use other input pins.
> > Are they feasible? Any new ideas or suggestions?
> Once i built an interface-card with 10 outputs (8 bit plus 2 that I
> can't remember... I think it was pin 13+14 (Select + AutoFeed))
> and 3 input-bits (pins 10-12: Ack, Busy + paper out)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ maybe these may
> help you!
> All of the mentioned pins ought to be able to be set or reset rather
> than just triggered (as for example "Initialize Printer" would)
> Still another method of using buttons or such things may be the
> game-port as it supports 4 buttons.
> So far, Jim (Matthias Knopf)
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Lijun Zhu
Department of Physics
University of Houston
Houston, TX77204

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