#!/usr/bin/perl -w

use POSIX;

system("setserial", "/dev/ttyS3", "spd_vhi");
$fd = POSIX::open('/dev/ttyS3', O_RDWR | O_NOCTTY | O_NONBLOCK) or die "$! in open";

$termios = POSIX::Termios->new;
$termios->getattr($fd) or die "$! in getattr";

print $termios->getispeed, " ", $termios->getospeed, " ", POSIX::B9600, " ", POSIX::B38400, "\n";
$termios->setispeed(POSIX::B38400);
$termios->setospeed(POSIX::B38400);

$c_iflag = $termios->getiflag;
$new_iflag = ($c_iflag & ~(BRKINT | PARMRK | ISTRIP |
			  INLCR | IGNCR | ICRNL | IXON | IXOFF)) | IGNBRK;

$c_lflag = $termios->getlflag;
$new_lflag = $c_lflag & ~(ECHO | ECHOK | ICANON | ISIG | IEXTEN);

$c_oflag = $termios->getoflag;
$new_oflag = $c_oflag & ~(OPOST);

$c_cflag = $termios->getcflag;
$new_cflag = ($c_cflag  & ~(CSIZE | PARENB )) | CS8;

sub cbreak() {
    $termios->setiflag($new_iflag);
    $termios->setlflag($new_lflag);
    $termios->setoflag($new_oflag);
    $termios->setcflag($new_cflag);
    $termios->setcc(VTIME,1);
    $termios->setattr($fd, &POSIX::TCSANOW);
}

cbreak();

$old_count = 0;

for (;;) {
    select undef, undef, undef, 0.5;
    POSIX::tcflush($fd, &POSIX::TCIOFLUSH);
    $buff = 'E';
    print ">"; 
    POSIX::write($fd, $buff, 1);
    while (!defined ($ret = POSIX::read($fd,$encoder_buff, 4))) {
#        print "<";
    };

    $encoder_count = unpack("l", $encoder_buff);
    $speed = $encoder_count - $old_count;
    print "$ret $encoder_count $speed\n";
    $old_count = $encoder_count
};

POSIX::close($fd);