# # hello.txrx.45.py # # receive and display transmit-receive step response # hello.step.45.py serial_port # # Neil Gershenfeld # CBA MIT 11/6/11 # # (c) Massachusetts Institute of Technology 2011 # Permission granted for experimental and personal use; # license for commercial sale available from MIT # from Tkinter import * import serial WINDOW = 600 # window size eps = 0.75 # filter fraction filt = 0.0 # filtered value def idle(parent,canvas): global filt, eps # # idle routine # byte2 = 0 byte3 = 0 byte4 = 0 ser.flush() # # find framing # while 1: byte1 = byte2 byte2 = byte3 byte3 = byte4 byte4 = ord(ser.read()) if ((byte1 == 1) & (byte2 == 2) & (byte3 == 3) & (byte4 == 4)): break # # read and plot # up_low = ord(ser.read()) up_high = ord(ser.read()) down_low = ord(ser.read()) down_high = ord(ser.read()) up_value = 256*up_high + up_low down_value = 256*down_high + down_low value = (up_value - down_value) filt = (1-eps)*filt + eps*value x = int(.2*WINDOW + (.9-.2)*WINDOW*filt/10000.0) canvas.itemconfigure("text",text="%.1f"%filt) canvas.coords('rect1',.2*WINDOW,.05*WINDOW,x,.2*WINDOW) canvas.coords('rect2',x,.05*WINDOW,.9*WINDOW,.2*WINDOW) canvas.update() parent.after_idle(idle,parent,canvas) # # check command line arguments # if (len(sys.argv) != 2): print "command line: hello.txrx.45.py serial_port" sys.exit() port = sys.argv[1] # # open serial port # ser = serial.Serial(port,9600) ser.setDTR() # # set up GUI # root = Tk() root.title('hello.txrx.45.py (q to exit)') root.bind('q','exit') canvas = Canvas(root, width=WINDOW, height=.25*WINDOW, background='white') # canvas.create_text(.1*WINDOW,.125*WINDOW,text="1",font=("Helvetica", 24),tags="text",fill="#0000b0") canvas.create_rectangle(.2*WINDOW,.05*WINDOW,.3*WINDOW,.2*WINDOW, tags='rect1', fill='#b00000') canvas.create_rectangle(.3*WINDOW,.05*WINDOW,.9*WINDOW,.2*WINDOW, tags='rect2', fill='#0000b0') canvas.pack() # # start idle loop # root.after(100,idle,root,canvas) root.mainloop()