#!/usr/bin/python                                                                                                                                         
 
import time                                                                                                                                               
 
import serial
 
s0 = serial.Serial("/dev/ttyUSB0")
 
s0.flushInput()
s0.bytesize = serial.EIGHTBITS
s0.parity   = serial.PARITY_NONE
s0.stopbit  = serial.STOPBITS_ONE
s0.baudrate = 9600
s0.timeout  = 0
s0.xonxoff  = False

t = time.time()
t_old = t
while True:
    a = ''
    a_ = 0

    if s0.inWaiting():
        a = hex(ord(s0.read(1)))
        a_ = eval(a)
        t= time.time()
    if a:
       if (t-t_old) < 0.025: 
         print " %4s" % a,
       else:
         print " "
         print "%.3f:" % (t-t_old),
         print " %4s" % a,
    t_old = t