# This code allows you to type your message in Python Shell and it will appear
# on the LCD.
# To kill the program, when 'Clear?' appears in the shell, type '-kill-'
#
# 16x2 LCD Typing Script
#
# The wiring for the LCD is as follows:
# All GPIO numbering is BCM format, not BOARD.
#
# LCD Screen                 Raspberry Pi
# 1 : GND                    - GND
# 2 : 5V                     - 5V
# 3 : Contrast               - GND w/2.2k Ohm resistor
# 4 : RS (Register Select)   - GPIO 26
# 5 : R/W (Read Write)       - GND
# 6 : Enable or Strobes      - GPIO 19
# 7 : Data Bit 0             - NOT USED
# 8 : Data Bit 1             - NOT USED
# 9 : Data Bit 2             - NOT USED
# 10: Data Bit 3             - NOT USED
# 11: Data Bit 4             - GPIO 13
# 12: Data Bit 5             - GPIO 6
# 13: Data Bit 6             - GPIO 5
# 14: Data Bit 7             - GPIO 11
# 15: LCD Backlight          - 5V w/270 Ohm resistor
# 16: LCD Backlight          - GND

#import
import RPi.GPIO as GPIO
import time

# Define GPIO to LCD mapping
LCD_RS = 26
LCD_E  = 19
LCD_D4 = 13
LCD_D5 = 6
LCD_D6 = 5
LCD_D7 = 11


# Define some device constants
LCD_WIDTH = 16    # Maximum characters per line
LCD_CHR = True
LCD_CMD = False

LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line

# Timing constants
E_PULSE = 0.0005
E_DELAY = 0.0005


def lcd_init():
  GPIO.setwarnings(False)
  GPIO.setmode(GPIO.BCM)       # Use BCM GPIO numbers
  GPIO.setup(LCD_E, GPIO.OUT)  # E
  GPIO.setup(LCD_RS, GPIO.OUT) # RS
  GPIO.setup(LCD_D4, GPIO.OUT) # DB4
  GPIO.setup(LCD_D5, GPIO.OUT) # DB5
  GPIO.setup(LCD_D6, GPIO.OUT) # DB6
  GPIO.setup(LCD_D7, GPIO.OUT) # DB7
  # Initialise display
  lcd_byte(0x33,LCD_CMD) # 110011 Initialise
  lcd_byte(0x32,LCD_CMD) # 110010 Initialise
  lcd_byte(0x06,LCD_CMD) # 000110 Cursor move direction
  lcd_byte(0x0C,LCD_CMD) # 001100 Display On,Cursor Off, Blink Off
  lcd_byte(0x28,LCD_CMD) # 101000 Data length, number of lines, font size
  lcd_byte(0x01,LCD_CMD) # 000001 Clear display
  time.sleep(E_DELAY)

def lcd_byte(bits, mode):
  # Send byte to data pins
  # bits = data
  # mode = True  for character
  #        False for command

  GPIO.output(LCD_RS, mode) # RS

  # High bits
  GPIO.output(LCD_D4, False)
  GPIO.output(LCD_D5, False)
  GPIO.output(LCD_D6, False)
  GPIO.output(LCD_D7, False)
  if bits&0x10==0x10:
    GPIO.output(LCD_D4, True)
  if bits&0x20==0x20:
    GPIO.output(LCD_D5, True)
  if bits&0x40==0x40:
    GPIO.output(LCD_D6, True)
  if bits&0x80==0x80:
    GPIO.output(LCD_D7, True)

  # Toggle 'Enable' pin
  lcd_toggle_enable()

  # Low bits
  GPIO.output(LCD_D4, False)
  GPIO.output(LCD_D5, False)
  GPIO.output(LCD_D6, False)
  GPIO.output(LCD_D7, False)
  if bits&0x01==0x01:
    GPIO.output(LCD_D4, True)
  if bits&0x02==0x02:
    GPIO.output(LCD_D5, True)
  if bits&0x04==0x04:
    GPIO.output(LCD_D6, True)
  if bits&0x08==0x08:
    GPIO.output(LCD_D7, True)

  # Toggle 'Enable' pin
  lcd_toggle_enable()

def lcd_toggle_enable():
  # Toggle enable
  time.sleep(E_DELAY)
  GPIO.output(LCD_E, True)
  time.sleep(E_PULSE)
  GPIO.output(LCD_E, False)
  time.sleep(E_DELAY)

def lcd_string(message,style):
  # Send string to display
  # style = 1 Left justified
  # style = 2 Centered
  # style = 3 Right justified

  if style==1:
    message = message.ljust(LCD_WIDTH," ")
  elif style==2:
    message = message.center(LCD_WIDTH," ")
  elif style==3:
    message = message.rjust(LCD_WIDTH," ")

  for i in range(LCD_WIDTH):
    lcd_byte(ord(message[i]),LCD_CHR)

if __name__ == '__main__':

  lcd_init()
  lcd_byte(LCD_LINE_1, LCD_CMD)
  lcd_string("Howdy!",2)    
  time.sleep(3)
  lcd_init()
  while True:
    lcd_byte(LCD_LINE_1, LCD_CMD) # sets curser to line 1
    lcdin = raw_input('Line 1: ')
    if len(lcdin) < 17:
        lcd_string(lcdin,2) 
    elif len(lcdin) > 16: # if text is too long for the LCD:
        print 'Too many caracters for line 1'

    lcd_byte(LCD_LINE_2, LCD_CMD) # sets curser to line 2
    lcdin2 = raw_input('Line 2: ')
    if len(lcdin2) < 17:
        lcd_string(lcdin2,2)
    elif len(lcdin2) > 16: # if text is too long for the LCD:
        print 'Too many caracter for line 2'

    clear = raw_input('Clear? ') # asks if you want to clear lcd
    clear.lower
    if clear == 'y':
        lcd_init()
    elif clear == 'n':
        pass
    elif clear == '':
        lcd_init()
    elif clear == '1':
        lcd_init()
        lcd_string(lcdin2,2)
    elif clear == '2':
        lcd_init()
        lcd_string(lcdin,2)
    elif clear == '-kill-': # Use this command when it askes 'Clear?' to end program
        lcd_init()
        lcd_byte(LCD_LINE_1, LCD_CMD)
        lcd_string("Goodbye!",2)
        time.sleep(3)
        lcd_init()
        GPIO.cleanup()
        exit()