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<title>Callback Example</title></head>
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<H2>Callback Example</H2>
<pre><font color="#404040"><i>#!/usr/bin/perl</i></font>
<font color="#009A00"><i># If using interupts the HiPi::Interrupt module should be used
# before anything else in your script. This is because the
# module loads threads to handle interrupts for pins managed
# by HiPi::Device::GPIO, HiPi::BCM2835 and HiPi::Wiring.
# Loading first reduces your memory footprint and avoids issues
# with modules you may use that are not thread safe.</i></font>
use HiPi::Interrupt;
<font color="#009A00"><i># Some basic modules loaded</i></font>
use 5.14.0;
use strict;
use warnings;
use HiPi::Device::GPIO;
use HiPi::Constant qw( :raspberry );
<font color="#009A00"><i># instead of deriving a class we use HiPi::Interrupt::Handler
# directly and register callbacks for one or more of:
#
# start, add, remove, interrupt,
# error, continue, stop</i></font>
use HiPi::Interrupt::Handler;
my $handler = HiPi::Interrupt::Handler->new;
<font color="#009A00"><i># register a callback for interrupts</i></font>
$handler->register_callback('interrupt', sub {
my ($self, $msg ) = @_;
say'--------------------------------';
my $output = ( $msg->error ) ? 'ERROR MESSAGE' : uc($msg->action) . ' HANDLED';
say $output;
say qq( action : ) . $msg->action;
say qq( pinid : ) . $msg->pinid;
say qq( error : ) . $msg->error;
say qq( value : ) . $msg->value;
say qq( timestamp : ) . $msg->timestamp;
say qq( msgtext : ) . $msg->msgtext;
say qq( pinclass : ) . $msg->pinclass;
say'--------------------------------';
});
<font color="#009A00"><i># register a callback for start</i></font>
$handler->register_callback('start', sub {
my ($self) = @_;
say 'INTERRUPT HANDLING STARTED';
});
<font color="#009A00"><i># register a callback for stop</i></font>
$handler->register_callback('stop', sub {
my ($self) = @_;
say 'INTERRUPT HANDLING STOPPED';
});
<font color="#009A00"><i># Create the pin monitoring</i></font>
{
<font color="#009A00"><i># the pins we are going to use</i></font>
my $pinid1 = RPI_PAD1_PIN_13;
my $pinid2 = RPI_PAD1_PIN_11;
my $dev = HiPi::Device::GPIO->new;
<font color="#009A00"><i># setup a pin as input with a pull up
# resistor and falling edge interrupt
# using HiPi::Device::GPIO</i></font>
$dev->export_pin($pinid1);
my $pin1 = $dev->get_pin($pinid1);
$pin1->mode(RPI_PINMODE_INPT);
$pin1->set_pud(RPI_PUD_OFF);
$pin1->set_pud(RPI_PUD_UP);
$pin1->interrupt( RPI_INT_FALL );
<font color="#009A00"><i># setup a pin as input with a pull down
# resistor and rising edge interrupt
# using HiPi::Device::GPIO
# use the pin obj returned from
# the export_pin method</i></font>
my $pin2 = $dev->export_pin($pinid2);
$pin2->mode(RPI_PINMODE_INPT);
$pin2->set_pud(RPI_PUD_OFF);
$pin2->set_pud(RPI_PUD_DOWN);
$pin2->interrupt( RPI_INT_RISE );
<font color="#009A00"><i># add as many pins as we want</i></font>
$handler->add_pin($pin1);
$handler->add_pin($pin2);
}
<font color="#009A00"><i># run the application loop</i></font>
$handler->poll();
1;
</pre></FONT>
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