> > Just wanted to get some ideas on what the most efficient
> way to do the
> > following is using a polled (non-interrupt) routine:
> >
> > In my main program loop, the user has two pushbuttons to control the
> > following modes
> >
> > 1.  Press and release LEFT button to run mode 1
> > 2.  Press and hold LEFT button for 2 seconds to run mode 2
> > 3.  Press and release RIGHT button to run mode 3
> > 4.  Press and hold both LEFT and RIGHT buttons for 2
> seconds to run mode
> 4.
> >
> > I realize there are a million ways to do this, but I need
> some ideas on
> how
> > to do this most efficiently.
> > Thanks
> >
> > D
> >
>
> If you draw a state diagram you will see that requirement 4
> has conflicts. A
> state diagram will help you refine your protocol and identify
> unique events
> which you can use to simplify your code.
>
> Regards
> Sergio Masci
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>

> Pressing the button for 1.9 seconds will be seen as a short
> push, as will
> 2.56 seconds as you overflow the char used for count.  You're
> asking your
> user to accurately time the button press to within half a
> second, lots of
> people can't.  You may want to use a 16 bit variable for count.
>
> Another method: when you see the button pushed, delay two
> seconds or so.
> If the button is not still pressed, it's a short push; if it
> is, it's a
> long push.  Maybe blink an LED or beep something to let the user know
> he/she can release the button at that point, then wait until they do
> release it before moving on.
>
> Dale
> --
> It's a thankless job, but I've got a lot of Karma to burn off.
>
> --
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>

> I came up with the following routine for the following.  Let me know what
> you think.
> If the pushbutton is pressed and released less than 2 seconds, the program
> runs MODE1 and if the button is held for
> greater than 2 seconds, SET-UP mode is run
>
>
> char count;
> count=0;
> if (input(PB1)==0)
>         {
>         delay_ms(20);           // Simple Debounce
>         while (input(PB1)==0)
>                 {
>                 count++;
>                 delay_ms(10);
>                 }
>         if (count < 200)
>                 RunMode1 ();
>         else
>                 SetUpMode ();
>         }
>
> Anyone see any problems (debouncing etc...) with this simple routine???
> Thanks much.
>
> Dan
>

> Thanks.  I'll probably keep the count at 255, but code it so it doesn't
> overflow, or probably have it so
> that when the timer reaches 2 seconds, it will automatically enter SETUP
> MODE.  Thats probably better anyways, this way
> the user doesn't have to time it.  Just hold the button until the mode
> changes.
>
> Dan
>
> > Pressing the button for 1.9 seconds will be seen as a short
> > push, as will
> > 2.56 seconds as you overflow the char used for count.  You're
> > asking your
> > user to accurately time the button press to within half a
> > second, lots of
> > people can't.  You may want to use a 16 bit variable for count.
> >
> > Another method: when you see the button pushed, delay two
> > seconds or so.
> > If the button is not still pressed, it's a short push; if it
> > is, it's a
> > long push.  Maybe blink an LED or beep something to let the user know
> > he/she can release the button at that point, then wait until they do
> > release it before moving on.
> >
> > Dale
> > --
> > It's a thankless job, but I've got a lot of Karma to burn off.
> >
> > --
> > http://www.piclist.com#nomail Going offline? Don't AutoReply us!
> > email spamBeGonelistservspamBeGonemitvma.mit.edu with SET PICList DIGEST in the body