sub new {
    my ($self, %args) = @_;
    $self = bless {%args}, $self;

    if (! $ENV{NO_BOARD}){
        if (my $scheme = $ENV{RPI_PIN_MODE}){
            # this checks if another application has already run
            # a setup routine

            $self->pin_scheme($scheme);
        }
        else {
            # we default to gpio mode

            if (! defined $self->{setup}) {
                $self->SUPER::setup_gpio();
                $self->pin_scheme(RPI_MODE_GPIO);
            }
            else {
                if ($self->_setup =~ /^w/) {
                    $self->SUPER::setup();
                    $self->pin_scheme(RPI_MODE_WPI);
                }
                elsif ($self->_setup =~ /^g/) {
                    $self->SUPER::setup_gpio();
                    $self->pin_scheme(RPI_MODE_GPIO);
                }
                elsif ($self->_setup =~ /^p/) {
                    $self->SUPER::setup_phys();
                    $self->pin_scheme(RPI_MODE_PHYS);
                }
                elsif ($self->_setup =~ /^W/){
                    $self->pin_scheme(RPI_MODE_WPI);
                }
                else {
                    $self->pin_scheme(RPI_MODE_UNINIT);
                }
            }
        }
        # set the env var so we can catch multiple
        # setup calls properly

        $ENV{RPI_SCHEME} = $self->pin_scheme;
    }
    $self->_fatal_exit;
    return $self;
}