NAME

RPi::Pin - Access and manipulate Raspberry Pi GPIO pins

SYNOPSIS

    use RPi::Pin;
    use RPi::Const qw(:all);

    my $pin = RPi::Pin->new(5);

    $pin->mode(INPUT);
    $pin->write(LOW);

    $pin->set_interrupt(EDGE_RISING, 'main::pin5_interrupt_handler');

    my $num = $pin->num;
    my $mode = $pin->mode;
    my $state = $pin->read;

    print "pin number $num is in mode $mode with state $state\n";

    sub pin5_interrupt_handler {
        print "in interrupt handler\n";
    }

DESCRIPTION

An object that represents a physical GPIO pin.

Using the pin object's methods, the GPIO pins can be controlled and monitored.

This distribution can be accessed through RPi::WiringPi. Using that distribution provides safety and cleanup procedures. Using this module directly requires you to reset your pins manually.

We use the BCM (GPIO) pin numbering scheme.

METHODS

new($pin_num, $comment)

Takes the number representing the Pi's GPIO pin you want to use, and returns an object for that pin.

Parameters:

    $pin_num

Mandatory, Integer: The pin number to attach to.

    $comment

Optional, String: A custom name or purpose description to associate this pin with.

comment($comment)

Sets/gets a description or name for the pin.

Parameters:

    $comment

Optional, String: If sent in, we'll set the pin's comment to this value.

Return: The currently set comment for the pin.

mode($mode)

Puts the pin into either INPUT, OUTPUT, PWM_OUT or GPIO_CLOCK mode. If $mode is not sent in, we'll return the pin's current mode.

Parameters:

    $mode

Optional: If not sent in, we'll simply return the current mode of the pin. Otherwise, send in: 0 for INPUT, 1 for OUTPUT, 2 for PWM_OUT and 3 for GPIO_CLOCK mode.

mode_alt($alt)

Allows you to set any pin to any mode.

Parameters:

    $alt

Optional: If not sent in, we'll simply return the current mode of the pin. The possible values of this method are as follows:

    Value   Mode
    ------------
    0       INPUT
    1       OUTPUT
    4       ALT0
    5       ALT1
    6       ALT2
    7       ALT3
    3       ALT4
    2       ALT5

read()

Returns 1 if the pin is HIGH (on) and 0 if the pin is LOW (off).

write($state)

For pins in OUTPUT mode, will turn HIGH (on) the pin, or LOW (off).

Parameters:

    $state

Send in 1 to turn the pin on, and 0 to turn it off.

pull($direction)

Used to set the internal pull-up or pull-down resistor for a pin. Calling this method on a pin will automatically set the pin to INPUT mode.

Parameter:

    $direction

Mandatory: 2 for PUD_UP, 1 for PUD_DOWN and 0 for PUD_OFF (disabled the resistor).

set_interrupt($edge, $callback)

Listen for an interrupt on a pin, and do something if it is triggered.

Parameters:

    $edge

Mandatory: 1 for EDGE_FALLING, 2 for EDGE_RISING, or 3 for EDGE_BOTH.

    $callback

The string name of a Perl subroutine that you've already written within your code. This is the interrupt handler. When an interrupt is triggered, the code in this subroutine will run. If you get errors when the handler is called, specify the full package name to the handler (eg: 'main::callback').

interrupt_set

DEPRECATED; See set_interrupt().

pwm($value)

Sets the level of the Pulse Width Modulation (PWM) of the pin. Dies if the pin's mode() is not set to PWM (2). Note that only physical pin 12 (wiringPi pin 1, GPIO pin 18) is PWM hardware capable.

Parameter:

    $value

Mandatory: values range from 0-1023. 0 for 0% (off) and 1023 for 100% (fully on).

See "pwm_range-range" in RPi for details on how to modify the range to something other than 0-1023.

num()

Returns the pin number associated with the pin object.

SEE ALSO

AUTHOR

Steve Bertrand, <steveb@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2017-2019 by Steve Bertrand

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.18.2 or, at your option, any later version of Perl 5 you may have available.

cpanm RPi::Pin

perl -MCPAN -e shell
install RPi::Pin