serio

#! /usr/bin/env python

# serio:
# A simple terminal communications program to talk over a serial line.

# This grew out of my ardmonitor script for talking to Arduinos.

# It's *just a proof of concept*; it doesn't work very well.
# Sometimes it randomly seems to skip characters or add delays.

# Copyright 2013 by Akkana Peck; share and enjoy under the GPLv2 or later.

import sys
import serial, select
import tty, termios
import signal

class SerIO() :
    def __init__(self) :
        self.old_settings = termios.tcgetattr(sys.stdin.fileno())

    def run(self, baud=115200) :
        # Port may vary, so look for it:
        baseports = ['/dev/ttyUSB']
        self.ser = None
        for baseport in baseports :
            if self.ser : break
            for i in xrange(0, 8) :
                try :
                    port = baseport + str(i)
                    self.ser = serial.Serial(port, baud, timeout=1)
                    print "Opened", port
                    break
                except :
                    self.ser = None
                    pass

        if not self.ser :
            print "Couldn't open a serial port"
            sys.exit(1)

        signal.signal(signal.SIGINT, self.signal_handler)

        tty.setraw(sys.stdin.fileno())

        self.ser.flushInput()
        while True :
            # Check whether the user has typed anything:
            inp, outp, err = select.select([sys.stdin, self.ser], [], [], .2)

            # Check for user input:
            if sys.stdin in inp :
                line = sys.stdin.read(1)
                self.ser.write(line)

            # check for output from the other end:
            if self.ser in inp :
                line = self.ser.read(1)
                sys.stdout.write(line)

            sys.stdout.flush()

    def signal_handler(self, signal, frame):
        print 'You pressed Ctrl+C! Cleaning up.'
        self.cleanup()
        sys.exit(0)

    def cleanup(self) :
        print "Calling cleanup"
        termios.tcsetattr(sys.stdin.fileno(), termios.TCSADRAIN,
                          self.old_settings)

serio = SerIO()
try :
    if len(sys.argv) > 1 :
        print "Using", sys.argv[1], "baud"
        serio.run(baud=sys.argv[1])
    else :
        serio.run()
except serial.SerialException :
    print "Disconnected (Serial exception)"
except IOError :
    print "Disconnected (I/O Error)"
except KeyboardInterrupt :
    print "Interrupt"

finally :
    print "finally: Cleaning up"
    serio.cleanup()