sub lcd_char_def {
    shift if @_ == 4;
    my ($fd, $index, $data) = @_;
    my $unsigned_char = pack "V0C*", @$data;
    lcdCharDef($fd, $index, $unsigned_char);
}
sub lcd_put_char {
    shift if @_ == 3;
    my ($fd, $data) = @_;
    lcdPutchar($fd, $data);
}