#!/usr/bin/python

import time
import serial
import signal
import sys, csv
import pygame

class Serial(serial.PosixSerial,serial.FileLike):
        #workaround for python 2.6 seriall behavior, http://code.google.com/p/python-on-a-chip/issues/detail?id=110
        pass

ser = Serial(
	port='/dev/ttyUSB0',
	baudrate=115200,
)

def signal_handler(signal, frame):
        print "closing serial port"
        ser.close()
        sys.exit(0)
        
signal.signal(signal.SIGINT, signal_handler)
tStart=time.time()
waiting=True
print "Starting..."
while waiting:
        ser.write('a') #start comms
        time.sleep(0.1);
        while time.time()-tStart<1.0 and waiting :
                if ser.inWaiting() >0:
                         print ser.readline()
                         waiting=False
                time.sleep(0.1);
        if waiting:
                print "Timeout,restarting..."
                tStart=time.time()
window = pygame.display.set_mode((640, 512))
y=127
times=[]
tSec=40;
while 1:
        if ser.inWaiting() >0:
                i=ser.readline(eol=chr(0))
                #print "received packet:",len(i),"bytes"
                pygame.draw.rect(window,(0,0,0),(0,0, 640,512))
                for x in range(0,len(i)-1): #skip end char
                        y1=ord(i[x])
                        pygame.draw.line(window, (255, 255, 255), (x*2, y*2), ((x*2)+2, y1*2))
                        y=y1
                        
                tNow=time.time();
                times.append(tNow-tStart);
                tStart=tNow
                if len(times)>320:
                        times.pop(0)
                for x in range(0,len(times)-1): #skip end char
                        pygame.draw.line(window, (255, 0, 0), (x*2, 512-(255*times[x]*tSec)), ((x*2)+2, 512-(255*times[x]*tSec)) )
                pygame.display.flip()
                
        time.sleep(0.01)