#!/usr/bin/python

# The wiring for the LCD is as follows:
# 1 : GND
# 2 : 5V
# 3 : Contrast (0-5V)*
# 4 : RS (Register Select)
# 5 : R/W (Read Write)
# 6 : - GROUND THIS PIN
# 7 : Enable or Strobe
# 8 : Data Bit 0 - NOT USED
# 9 : Data Bit 1 - NOT USED
# 10: Data Bit 2 - NOT USED
# 11: Data Bit 3 - NOT USED
# 12: Data Bit 4
# 13: Data Bit 5
# 14: Data Bit 6
# 15: Data Bit 7
# 16: LCD Backlight +5V**
# 17: LCD Backlight GND

import RPi.GPIO as GPIO
import time
import sys

# Define GPIO to LCD mapping
LCD_RS = 7
LCD_E = 8
LCD_D4 = 25
LCD_D5 = 24
LCD_D6 = 23
LCD_D7 = 18

# 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():
    # 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 Initialise
    time.sleep(E_DELAY)


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_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_string(message, line):
    # Send string to display
    message = message.ljust(LCD_WIDTH, " ")
    lcd_byte(line, LCD_CMD)
    for i in range(LCD_WIDTH):
        lcd_byte(ord(message[i]), LCD_CHR)


def lcd_string_print(string,line,length):
    for x in range(0, len(string)-length):
        lcd_string(string[x:x+length],line)
        time.sleep(0.5)

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)  # DB7
GPIO.setup(LCD_D7, GPIO.OUT)
# Initialise display
lcd_init()
