LCD Brick for Raspberry Pi (20×4)

Product Description

LCD can display 20 characters on four lines, backlight is blue and has a backpack that lets you adjust brightness and connect the Raspberry Pi using 8 wires mother-mother.

Further down are the instructions needed to run the source code in Python.

1. Login via SSH Raspberry and navigehaza the Desktop directory.

$ Cd Desktop

2. Create a file called lcd.py and copy the code below to copy paste.

$ Sudo nano lcd.py

import RPi.GPIO as GPIO
import time
 

LCD_RS = 7
LCD_E  = 8
LCD_D4 = 25
LCD_D5 = 24
LCD_D6 = 23
LCD_D7 = 18
LED_ON = 15
 

LCD_WIDTH = 20    
LCD_CHR = True
LCD_CMD = False
 
LCD_LINE_1 = 0x80 
LCD_LINE_2 = 0xC0 
LCD_LINE_3 = 0x94 
LCD_LINE_4 = 0xD4 
 

E_PULSE = 0.0005
E_DELAY = 0.0005
 
def main():
 
 
  GPIO.setmode(GPIO.BCM)       
  GPIO.setup(LCD_E, GPIO.OUT)  
  GPIO.setup(LCD_RS, GPIO.OUT) 
  GPIO.setup(LCD_D4, GPIO.OUT) 
  GPIO.setup(LCD_D5, GPIO.OUT) 
  GPIO.setup(LCD_D6, GPIO.OUT) 
  GPIO.setup(LCD_D7, GPIO.OUT) 
 
  lcd_init()

 
  while True:

    lcd_string("--------------------",LCD_LINE_1,2)
    lcd_string("Robofun.ro",LCD_LINE_2,2)
    lcd_string("Raspberry Pi 2",LCD_LINE_3,2)
    lcd_string("--------------------",LCD_LINE_4,2)
 

 
def lcd_init():
 
  lcd_byte(0x33,LCD_CMD) 
  lcd_byte(0x32,LCD_CMD) 
  lcd_byte(0x06,LCD_CMD) 
  lcd_byte(0x0C,LCD_CMD) 
  lcd_byte(0x28,LCD_CMD)
  lcd_byte(0x01,LCD_CMD) 
  time.sleep(E_DELAY)
 
def lcd_byte(bits, mode):
 
  GPIO.output(LCD_RS, mode)
 
  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)
 
  lcd_toggle_enable()

  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)

  lcd_toggle_enable()
 
def lcd_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,line,style):
 
  if style==1:
    message = message.ljust(LCD_WIDTH," ")
  elif style==2:
    message = message.center(LCD_WIDTH," ")
  elif style==3:
    message = message.rjust(LCD_WIDTH," ")
 
  lcd_byte(line, LCD_CMD)
 
  for i in range(LCD_WIDTH):
    lcd_byte(ord(message[i]),LCD_CHR)
 
def lcd_backlight(flag):

  GPIO.output(LED_ON, flag)
 
if __name__ == '__main__':
 
  try:
    main()
  except KeyboardInterrupt:
    pass
  finally:
    lcd_byte(0x01, LCD_CMD)
    lcd_string("www.RoboFun.ro",LCD_LINE_1,2)
    GPIO.cleanup()

3.Use Ctrl + A to save your changes and Ctrl + X to close the text editor.