Sure Electronics DE-LD011 Python "driver"

#!/usr/local/bin/python


# Sure Electronics' DE-LD011 Driver

# This is a crude attempt at a "driver" for the
# Sure Electronics DE-LD011 16x2 Character LCD
# display. Use it was you will, it is Public Domain

# Originally written by Chase Phillips, 2/26/2012


import serial, time

CMD = chr(254)
WRITE = chr(71)


# Backlight hex commands
BACKLIGHT_OFF = [ chr(254), chr(70) ]
BACKLIGHT_ON = [ chr(254), chr(66), chr(00) ]
BACKLIGHT_LOW = [ chr(254), chr(152), chr(37) ]
BACKLIGHT_MED = [ chr(254), chr(152), chr(80) ]
BACKLIGHT_HI = [ chr(254), chr(152), chr(153) ]

# Hex sequence to clear the screens
CLEARSCREEN = [
                # clear the first line
                chr(254), chr(71), chr(1), chr(1), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20),
                chr(20), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20),

                # clear the second line
                chr(254), chr(71), chr(1), chr(2), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20),
                chr(20), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20), chr(20)
              ]


# This is the meat
class Driver:

    # Assign the COM port when called
    def __init__(self, com):
        try:
            self.s = serial.Serial(com, 9600,
                                   serial.EIGHTBITS,
                                   serial.PARITY_NONE,
                                   serial.STOPBITS_ONE,
                                   timeout = 5,
                                   rtscts = False)

        except serial.SerialException:
            return False


    # These are simple backlight controls. They don't
    # take any arguments
    def BacklightOn(self):
        for i in BACKLIGHT_ON:
            self.s.write(i)

        return True


    def BacklightOff(self):
        for i in BACKLIGHT_OFF:
            self.s.write(i)

        return True


    def BacklightLevel(self, val):
        if val > 3:
            print "Value must be between 1 and 3"

            return False
        elif val ==  1:
            for i in BACKLIGHT_LOW:
                self.s.write(i)

                return True

        elif val == 2:
            for i in BACKLIGHT_MED:
                self.s.write(i)

                return True

        elif val == 3:
            for i in BACKLIGHT_HI:
                self.s.write(i)

                return True


    # This will clear the entire screen
    def ClearScreen(self):
        for i in CLEARSCREEN:
            self.s.write(i)



    # This writes the string to the unit. If the
    # string is longer than the 16-character limit
    # of the screen, the text will automagically
    # scroll
    #
    # Usage:
    # Driver.WriteLine("String", 1, 1)
    # This will write "String" to the first row
    # starting at the first column
    def WriteLine(self, data, row, col):
        if len(data) > 16:
            ii = 0

            while ii != len(data):
                lst = [CMD, WRITE, chr(col), chr(row)]

                for c in data[ii:ii+16]:
                    lst.append(chr(int(c.encode('hex'), 16)))

                if len(lst) < 20:
                    while len(lst) < 20:
                        lst.append(chr(20))

                for i in lst:
                    self.s.write(i)

                # Change this if you want the text to scroll faster
                time.sleep(.3)

                ii = ii + 1

        else:
            lst = [CMD, WRITE, chr(col), chr(row)]

            for c in data:
                lst.append(chr(int(c.encode('hex'), 16)))

            if len(lst) < 20:
                while len(lst) < 20:
                    lst.append(chr(20))

            for i in lst:
                self.s.write(i)