Added support for 16x2 LCD scren for output messages

Author: michaelplews

lcd_16x2.py

@@ -0,0 +1,206 @@
+#!/usr/bin/python
+#--------------------------------------
+#    ___  ___  _ ____
+#   / _ \/ _ \(_) __/__  __ __
+#  / , _/ ___/ /\ \/ _ \/ // /
+# /_/|_/_/  /_/___/ .__/\_, /
+#                /_/   /___/
+#
+#  lcd_16x2.py
+#  16x2 LCD Test Script
+#
+# Author : Matt Hawkins
+# Date   : 06/04/2015
+#
+# http://www.raspberrypi-spy.co.uk/
+#
+# Copyright 2015 Matt Hawkins
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+#--------------------------------------
+
+# 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)       - GROUND THIS PIN
+# 6 : Enable or Strobe
+# 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
+# 12: Data Bit 5
+# 13: Data Bit 6
+# 14: Data Bit 7
+# 15: LCD Backlight +5V**
+# 16: LCD Backlight GND
+
+#import
+import RPi.GPIO as GPIO
+import time
+
+# Define GPIO to LCD mapping
+LCD_RS = 25
+LCD_E  = 19
+LCD_D4 = 13
+LCD_D5 = 6
+LCD_D6 = 5
+LCD_D7 = 12
+
+
+# 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 main():
+  # Main program block
+
+  # Initialise display
+  lcd_init()
+
+  while True:
+
+    # Send some test
+    lcd_string("Rasbperry Pi",LCD_LINE_1)
+    lcd_string("16x2 LCD Test",LCD_LINE_2)
+
+    time.sleep(3) # 3 second delay
+
+    # Send some text
+    lcd_string("1234567890123456",LCD_LINE_1)
+    lcd_string("abcdefghijklmnop",LCD_LINE_2)
+
+
+
+    time.sleep(3) # 3 second delay
+
+    # Send some text
+    lcd_string("RaspberryPi-spy",LCD_LINE_1)
+    lcd_string(".co.uk",LCD_LINE_2)
+
+    time.sleep(3)
+
+    # Send some text
+    lcd_string("Follow me on",LCD_LINE_1)
+    lcd_string("Twitter @RPiSpy",LCD_LINE_2)
+
+    time.sleep(3)
+
+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,line,just="l"):
+  """Sends a string to the display. Default justification is left."""
+
+  if just=="r":
+    message = message.rjust(LCD_WIDTH," ")
+  elif just=="c":
+    message = message.center(LCD_WIDTH," ")
+  else:
+    message = message.ljust(LCD_WIDTH," ")
+    
+  lcd_byte(line, LCD_CMD)
+
+  for i in range(LCD_WIDTH):
+    lcd_byte(ord(message[i]),LCD_CHR)
+
+if __name__ == '__main__':
+
+  try:
+    main()
+  except KeyboardInterrupt:
+    pass
+  finally:
+    lcd_byte(0x01, LCD_CMD)
+    lcd_string("Goodbye!",LCD_LINE_1)
+    GPIO.cleanup()