raspberry pi char lcd driver code code in action: http://www.youtube.com/watch?v=zVc76BmyIsM

rpi_lcd.py

#!/usr/bin/python

import RPi.GPIO as GPIO
from time import sleep

class HD44780:

  def __init__(self, pin_rs=7, pin_e=8, pins_db=[25, 24, 23, 18]):
    
    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.cmd(0x33) # $33 8-bit mode
    self.cmd(0x32) # $32 8-bit mode
    self.cmd(0x28) # $28 8-bit mode
    self.cmd(0x0C) # $0C 8-bit mode
    self.cmd(0x06) # $06 8-bit mode
    self.cmd(0x01) # $01 8-bit mode

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

    sleep(0.001)
    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"""

    for char in text:
      if char == '\n':
        self.cmd(0xC0) # next line
      else:
        self.cmd(ord(char),True)

if __name__ == '__main__':

  lcd = HD44780()
  lcd.message(" Raspberry Pi\n Take a byte!")
  try:
    while True:
      s = raw_input("type: ")
      lcd.clear()
      lcd.message(" "+s[:16]+"\n"+s[16:])
  except:
    pass
  GPIO.cleanup()
  print #empty line