i''m new, need help with command
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You bring up a good point. When I read Jon's pdf file he linked a
couple messages ago, I saw that POLLWAIT would let the stamp "nap"
until a polled event happens. If I don't do the polling option and
just run the small continuous loop looking for a switch input, is
there anything wrong with leaving the stamp in 'full power' mode?
This won't be on battery power, so I'm not concerned with drawing
down a battery or anything. Would it hurt the stamp to stay active
all the time and not go into the nap mode?
Thanks
--- In basicstamps@yahoogroups.com, Tracy Allen <tracy@e...> wrote:
> Hi again Andy,
>
> Yes, that straight out scan is going to be simpler than the mind
set
> for the POLLing commands. And yes, 0.5 second is forever in
> microcomputer terms. On the Stamp, each one of those instructions
> like
> > > IF (ButtonA = 1) THEN BtnA_Sub
> will take about 1 millisecond to execute, so the entire loop to
scan
> 4 pushbuttons will execute in well under 10 milliseconds.
>
> Note that you also have to allow for the case that someone leans on
> one of the buttons. If you don't want the button action to occur
over
> and over, you will have to write code to do the action once per
> event. Take a look at the BUTTON command, which has such
debounce.
> However, everyone agrees that with several buttons involved it is
> more efficient & flexible to write your own code to do that.
>
> The simple scanning will be more of a problem if the Stamp has to
do
> a lot of other processing at the same time, or if you want it to
> catch a quick 0.05 second button press or a similar signal that
comes
> from an instrument like a tipping bucket rain gage. Or, if the
> program has to conserve power while waiting for a button to be
> pressed. The POLLIN latched modes work really well with the
POLLWAIT
> command on the BS2pe/pe, so the chip can nap until an event happens
> and then test the scratchpad registers to determine which event(s).
>
> You mentioned an RC input network. That can effectively stretch
> events like the 30 millisecond rain gage pulse. Just a 0.1uf
> capacitor from the Stamp input to ground, and 270 ohm resistors to
> limit the current to the stamp pin and to the switch. The stamp
pin
> is an output to charge the capacitor. The program returns about
once
> a second to check the voltage on the pin and to refresh it. If it
> finds zero volts, that means the switch has closed in the interim.
> The Stamp adds one to the count before refreshing the charge on the
> capacitor.
>
> -- Tracy
>
>
>
>
>
> >Well, by "quick", I mean that the pin will only be high for maybe
0.5
> >seconds. Assuming that the only thing going is the loop looking
for
> >a high on one of the 4 pins, I don't know if that 0.5 sec high is
> >long enough. Perhaps I could add some kind of RC circuit to keep
the
> >pin latched for an extra second or so. The POLLMODE latching stuff
> >looks a little more complicated. But if it's that much better,
I'll
> >try to figure it out.
> >
> >Thanks,
> >Andy
> >
> >--- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
> >wrote:
> >> The depends on how you define "quick" and keep in mind that
standard
> >> Stamp inputs are not latched. As Tracy suggested, however, you
can
> >use
> >> POLLIN instruction with a MODE that will latch polled inputs,
but
> >note
> >> that using POLL instructions work in between other things (the
> >Stamp is
> >> single threaded). In addition to the manual, and information on
> >Tracy's
> >> web site, you may find this article helpful:
> >>
> >> http://www.parallax.com/dl/docs/cols/nv/vol2/col/69.pdf
> >>
> >> -- Jon Williams
> >> -- Applications Engineer, Parallax
> >> -- Dallas Office
> >>
>
couple messages ago, I saw that POLLWAIT would let the stamp "nap"
until a polled event happens. If I don't do the polling option and
just run the small continuous loop looking for a switch input, is
there anything wrong with leaving the stamp in 'full power' mode?
This won't be on battery power, so I'm not concerned with drawing
down a battery or anything. Would it hurt the stamp to stay active
all the time and not go into the nap mode?
Thanks
--- In basicstamps@yahoogroups.com, Tracy Allen <tracy@e...> wrote:
> Hi again Andy,
>
> Yes, that straight out scan is going to be simpler than the mind
set
> for the POLLing commands. And yes, 0.5 second is forever in
> microcomputer terms. On the Stamp, each one of those instructions
> like
> > > IF (ButtonA = 1) THEN BtnA_Sub
> will take about 1 millisecond to execute, so the entire loop to
scan
> 4 pushbuttons will execute in well under 10 milliseconds.
>
> Note that you also have to allow for the case that someone leans on
> one of the buttons. If you don't want the button action to occur
over
> and over, you will have to write code to do the action once per
> event. Take a look at the BUTTON command, which has such
debounce.
> However, everyone agrees that with several buttons involved it is
> more efficient & flexible to write your own code to do that.
>
> The simple scanning will be more of a problem if the Stamp has to
do
> a lot of other processing at the same time, or if you want it to
> catch a quick 0.05 second button press or a similar signal that
comes
> from an instrument like a tipping bucket rain gage. Or, if the
> program has to conserve power while waiting for a button to be
> pressed. The POLLIN latched modes work really well with the
POLLWAIT
> command on the BS2pe/pe, so the chip can nap until an event happens
> and then test the scratchpad registers to determine which event(s).
>
> You mentioned an RC input network. That can effectively stretch
> events like the 30 millisecond rain gage pulse. Just a 0.1uf
> capacitor from the Stamp input to ground, and 270 ohm resistors to
> limit the current to the stamp pin and to the switch. The stamp
pin
> is an output to charge the capacitor. The program returns about
once
> a second to check the voltage on the pin and to refresh it. If it
> finds zero volts, that means the switch has closed in the interim.
> The Stamp adds one to the count before refreshing the charge on the
> capacitor.
>
> -- Tracy
>
>
>
>
>
> >Well, by "quick", I mean that the pin will only be high for maybe
0.5
> >seconds. Assuming that the only thing going is the loop looking
for
> >a high on one of the 4 pins, I don't know if that 0.5 sec high is
> >long enough. Perhaps I could add some kind of RC circuit to keep
the
> >pin latched for an extra second or so. The POLLMODE latching stuff
> >looks a little more complicated. But if it's that much better,
I'll
> >try to figure it out.
> >
> >Thanks,
> >Andy
> >
> >--- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
> >wrote:
> >> The depends on how you define "quick" and keep in mind that
standard
> >> Stamp inputs are not latched. As Tracy suggested, however, you
can
> >use
> >> POLLIN instruction with a MODE that will latch polled inputs,
but
> >note
> >> that using POLL instructions work in between other things (the
> >Stamp is
> >> single threaded). In addition to the manual, and information on
> >Tracy's
> >> web site, you may find this article helpful:
> >>
> >> http://www.parallax.com/dl/docs/cols/nv/vol2/col/69.pdf
> >>
> >> -- Jon Williams
> >> -- Applications Engineer, Parallax
> >> -- Dallas Office
> >>
>