[Gambas-user] Did anybody try to run stepper motors through paralel port

[Zelimir Ikovic]

Thank you all, in last few emails is answer!




--- On Sun, 4/18/10, Doriano Blengino <doriano.blengino at ...1909...> wrote:

> From: Doriano Blengino <doriano.blengino at ...1909...>
> Subject: Re: [Gambas-user] Did anybody try to run stepper motors through paralel port
> To: "mailing list for gambas users" <gambas-user at lists.sourceforge.net>
> Received: Sunday, April 18, 2010, 2:07 PM
> Zelimir Ikovic ha scritto:
> > I wanted to know how predictable and reliable GAMBAS
> is when a reaction to real-world events is required. 
> >
> > Let say that Java RealTimeSystem is intended only for
> suitable  operating systems, which means that only a 
> > real-time operating system, such as QNX, is
> appropriate for implementing the JVM.
> > So that means it depends on underlynig OS version ...
> >  
> >  Simply installing an RTS extension 
> >  and renaming java.lang.Thread instances to 
> >  javax.realtime.RealtimeThread will not turn the
> 
> >  application into a real-time app.
> >  
> >  I just wanted to know what is Gamas reaction to
> real world compared under different underlyng OS.
> >  FreeBSD, OpenBSD and Linux are not he same.
> >   
> I understand but, let me say, your sample code had nothing
> to do with 
> realtime... it was simply "fast as much as possible",
> without any 
> mechanism to ensure some kind of real-time response to some
> event. To 
> only read a counter is not enough. I can run 4 stepper
> motors directly 
> (no step+direction, but driving the phases directly
> instead) with a CPU 
> more than 100 times slower than a x86 CPU. But this is
> possible using 
> interrupts. Practically every OS can, in some way, use
> interrupts - 
> gambas can not. So, the only way in gambas to do precise
> timing is to 
> let it run alone, with maximum priority and privileges. Or,
> to delegate 
> high timing precision to some external piece of software (a
> libray or a 
> driver) which can take advantage of interrupts, or
> callbacks, or signals.
> 
> On the other hand I think that gambas can, with tight
> loops, do delays 
> like you did in the original source. Surely it is
> predictable enough to 
> let you calculate in some way the correct amount of cycling
> to obtain 
> the needed delay - the fact is that gambas will never be
> the only thing 
> running on the system, and you have little control about
> that. The same 
> problem of windows xp - if you want precise timing, you
> must obtain 
> privileges, either for the program or using a driver. I
> must also add 
> that, without particular precautions, linux is more
> predictable about 
> sleep() than win2000 or xp.
> 
> Regards,
> 
> -- 
> Doriano Blengino
> 
> "Listen twice before you speak.
> This is why we have two ears, but only one mouth."
> 
> 
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