Re: How to read the RS-232 lines?

[kb2yht]

I use Device::SerialPort for talking to the PIC UART:

use Device::SerialPort;

my $port = Device::SerialPort->new( "/dev/ttyS0" );
$port->baudrate(9600);
$port->databits(8);
$port->stopbits(1);
$port->parity("none");

my $string = '';
my $more = 1;
while($more) {
    my $pass = $port->write('S$');
    my $end_seen = 0;
    while ( not $end_seen ) {
        local $_ = $port->input;
        if ( $_ ne '' ) {
            if ( m/S:/ ) { # string start
                $string = $_;
            }
            elsif ( m/:$/ ) { # string end
                $string .= $_;
                print $string; # deal with the final string
                $end_seen=1;
                $more=0;
            }
            else {
                $string .= $_;
            }
        }
    }
}

Be warned - If you are trying to get something out cleanly in one try, it will probably not work. I found that I have to interrogate the PIC over and over to keep the UART alive and talking to me.