gistfile1.py

#!/usr/bin/python

import RPi.GPIO as GPIO
from time import sleep

class HD44780:

    def __init__(self, pin_rs=25, pin_e=24, pins_db=[23, 17, 21, 22]):

        self.pin_rs = pin_rs
        self.pin_e = pin_e
        self.pins_db = pins_db

        GPIO.setmode(GPIO.BCM)
        GPIO.setup(self.pin_e, GPIO.OUT)
        GPIO.setup(self.pin_rs, GPIO.OUT)
        for pin in self.pins_db:
            GPIO.setup(pin, GPIO.OUT)

        self.clear()

    def clear(self):
        """ Blank / Reset LCD """

        self.cmdinit(0x3) # $33 8-bit mode
        self.cmdinit(0x3) # $32 8-bit mode
        self.cmdinit(0x3) # $32 8-bit mode
        self.cmdinit(0x2) # $32 8-bit mode

        self.cmd(0x28) # $28 101000: 4bit,2line,5x8
        self.cmd(0x0C) # $0C   1100: display on
        self.cmd(0x06) # $06    110: cursor inc
        self.cmd(0x01) # $01      1: clear

    def cmdinit(self, bits):
        """ Send command to LCD """

        sleep(0.01)
        bits=bin(bits)[2:].zfill(8)

        for pin in self.pins_db:
            GPIO.output(pin, False)

        for i in range(4,8):
            if bits[i] == "1":
                GPIO.output(self.pins_db[::-1][i-4], True)

        GPIO.output(self.pin_e, True)
        GPIO.output(self.pin_e, False)
        sleep(0.01)

    def cmd(self, bits, char_mode=False):
        """ Send command to LCD """

        sleep(0.002)
        bits=bin(bits)[2:].zfill(8)

        GPIO.output(self.pin_rs, char_mode)

        for pin in self.pins_db:
            GPIO.output(pin, False)

        for i in range(4):
            if bits[i] == "1":
                GPIO.output(self.pins_db[::-1][i], True)

        GPIO.output(self.pin_e, True)
        GPIO.output(self.pin_e, False)

        for pin in self.pins_db:
            GPIO.output(pin, False)

        for i in range(4,8):
            if bits[i] == "1":
                GPIO.output(self.pins_db[::-1][i-4], True)

        GPIO.output(self.pin_e, True)
        GPIO.output(self.pin_e, False)

    def message(self, text):
        """ Send string to LCD. Newline wraps to second line"""
	self.cmd(2)
	i = 0
        for char in text:
            if char == '\n':
                self.cmd(0xC0) # next line
            else:
                self.cmd(ord(char),True)
                i = i + 1
                if i == 16:
                    self.cmd(0xC0)

    def customchars(self, data = [[0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0]]):
	i = 0
	self.cmd(0x40)
	for character  in data:
	    for line in character:
		self.cmd(line,True)

if __name__ == '__main__':
    import random
    from datetime import datetime

    charmap = [ [0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0],
    [0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x1f],
    [0x0,0x0,0x0,0x0,0x0,0x0,0x1f,0x1f],
    [0x0,0x0,0x0,0x0,0x0,0x1f,0x1f,0x1f],
    [0x0,0x0,0x0,0x0,0x1f,0x1f,0x1f,0x1f],
    [0x0,0x0,0x0,0x1f,0x1f,0x1f,0x1f,0x1f],
    [0x0,0x0,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f],
    [0x0,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f]
    ]

    lcd = HD44780()
    lcd.customchars(charmap)
    
    while 1:
        x = datetime.now().strftime('%b %d  %H:%M:%S\n')
        msg=''
        for num in range(16):
            msg = msg + chr(random.randint(0,7)) 
        lcd.message(x+msg)
        #sleep(0.01)