DenisFromHR · August 24, 2025 16:56 · Feb 9, 2015 · Feb 9, 2015
diff --git a/RPi_I2C_driver.py b/RPi_I2C_driver.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 """
-Copyright (C) 2014-2015 Denis Pleic
+Compiled, mashed and generally mutilated 2014-2015 by Denis Pleic
 Made available under GNU GENERAL PUBLIC LICENSE
 
 # Modified Python I2C library for Raspberry Pi

diff --git a/examples.py b/examples.py
@@ -1,3 +1,4 @@
+# requires RPi_I2C_driver.py
 import RPi_I2C_driver
 from time import *
 

diff --git a/RPi_I2C_driver.py b/RPi_I2C_driver.py
@@ -0,0 +1,189 @@
+# -*- coding: utf-8 -*-
+"""
+Copyright (C) 2014-2015 Denis Pleic
+Made available under GNU GENERAL PUBLIC LICENSE
+
+# Modified Python I2C library for Raspberry Pi
+# as found on http://www.recantha.co.uk/blog/?p=4849
+# Joined existing 'i2c_lib.py' and 'lcddriver.py' into a single library
+# added bits and pieces from various sources
+# By DenisFromHR (Denis Pleic)
+# 2015-02-10, ver 0.1
+
+"""
+#
+#
+import smbus
+from time import *
+
+class i2c_device:
+   def __init__(self, addr, port=1):
+      self.addr = addr
+      self.bus = smbus.SMBus(port)
+
+# Write a single command
+   def write_cmd(self, cmd):
+      self.bus.write_byte(self.addr, cmd)
+      sleep(0.0001)
+
+# Write a command and argument
+   def write_cmd_arg(self, cmd, data):
+      self.bus.write_byte_data(self.addr, cmd, data)
+      sleep(0.0001)
+
+# Write a block of data
+   def write_block_data(self, cmd, data):
+      self.bus.write_block_data(self.addr, cmd, data)
+      sleep(0.0001)
+
+# Read a single byte
+   def read(self):
+      return self.bus.read_byte(self.addr)
+
+# Read
+   def read_data(self, cmd):
+      return self.bus.read_byte_data(self.addr, cmd)
+
+# Read a block of data
+   def read_block_data(self, cmd):
+      return self.bus.read_block_data(self.addr, cmd)
+
+
+
+# LCD Address
+ADDRESS = 0x27
+
+# commands
+LCD_CLEARDISPLAY = 0x01
+LCD_RETURNHOME = 0x02
+LCD_ENTRYMODESET = 0x04
+LCD_DISPLAYCONTROL = 0x08
+LCD_CURSORSHIFT = 0x10
+LCD_FUNCTIONSET = 0x20
+LCD_SETCGRAMADDR = 0x40
+LCD_SETDDRAMADDR = 0x80
+
+# flags for display entry mode
+LCD_ENTRYRIGHT = 0x00
+LCD_ENTRYLEFT = 0x02
+LCD_ENTRYSHIFTINCREMENT = 0x01
+LCD_ENTRYSHIFTDECREMENT = 0x00
+
+# flags for display on/off control
+LCD_DISPLAYON = 0x04
+LCD_DISPLAYOFF = 0x00
+LCD_CURSORON = 0x02
+LCD_CURSOROFF = 0x00
+LCD_BLINKON = 0x01
+LCD_BLINKOFF = 0x00
+
+# flags for display/cursor shift
+LCD_DISPLAYMOVE = 0x08
+LCD_CURSORMOVE = 0x00
+LCD_MOVERIGHT = 0x04
+LCD_MOVELEFT = 0x00
+
+# flags for function set
+LCD_8BITMODE = 0x10
+LCD_4BITMODE = 0x00
+LCD_2LINE = 0x08
+LCD_1LINE = 0x00
+LCD_5x10DOTS = 0x04
+LCD_5x8DOTS = 0x00
+
+# flags for backlight control
+LCD_BACKLIGHT = 0x08
+LCD_NOBACKLIGHT = 0x00
+
+En = 0b00000100 # Enable bit
+Rw = 0b00000010 # Read/Write bit
+Rs = 0b00000001 # Register select bit
+
+class lcd:
+   #initializes objects and lcd
+   def __init__(self):
+      self.lcd_device = i2c_device(ADDRESS)
+
+      self.lcd_write(0x03)
+      self.lcd_write(0x03)
+      self.lcd_write(0x03)
+      self.lcd_write(0x02)
+
+      self.lcd_write(LCD_FUNCTIONSET | LCD_2LINE | LCD_5x8DOTS | LCD_4BITMODE)
+      self.lcd_write(LCD_DISPLAYCONTROL | LCD_DISPLAYON)
+      self.lcd_write(LCD_CLEARDISPLAY)
+      self.lcd_write(LCD_ENTRYMODESET | LCD_ENTRYLEFT)
+      sleep(0.2)
+
+
+   # clocks EN to latch command
+   def lcd_strobe(self, data):
+      self.lcd_device.write_cmd(data | En | LCD_BACKLIGHT)
+      sleep(.0005)
+      self.lcd_device.write_cmd(((data & ~En) | LCD_BACKLIGHT))
+      sleep(.0001)
+
+   def lcd_write_four_bits(self, data):
+      self.lcd_device.write_cmd(data | LCD_BACKLIGHT)
+      self.lcd_strobe(data)
+
+   # write a command to lcd
+   def lcd_write(self, cmd, mode=0):
+      self.lcd_write_four_bits(mode | (cmd & 0xF0))
+      self.lcd_write_four_bits(mode | ((cmd << 4) & 0xF0))
+
+   # write a character to lcd (or character rom) 0x09: backlight | RS=DR<
+   # works!
+   def lcd_write_char(self, charvalue, mode=1):
+      self.lcd_write_four_bits(mode | (charvalue & 0xF0))
+      self.lcd_write_four_bits(mode | ((charvalue << 4) & 0xF0))
+
+
+   # put string function
+   def lcd_display_string(self, string, line):
+      if line == 1:
+         self.lcd_write(0x80)
+      if line == 2:
+         self.lcd_write(0xC0)
+      if line == 3:
+         self.lcd_write(0x94)
+      if line == 4:
+         self.lcd_write(0xD4)
+
+      for char in string:
+         self.lcd_write(ord(char), Rs)
+
+   # clear lcd and set to home
+   def lcd_clear(self):
+      self.lcd_write(LCD_CLEARDISPLAY)
+      self.lcd_write(LCD_RETURNHOME)
+
+   # define backlight on/off (lcd.backlight(1); off= lcd.backlight(0)
+   def backlight(self, state): # for state, 1 = on, 0 = off
+      if state == 1:
+         self.lcd_device.write_cmd(LCD_BACKLIGHT)
+      elif state == 0:
+         self.lcd_device.write_cmd(LCD_NOBACKLIGHT)
+
+   # add custom characters (0 - 7)
+   def lcd_load_custom_chars(self, fontdata):
+      self.lcd_write(0x40);
+      for char in fontdata:
+         for line in char:
+            self.lcd_write_char(line)         
+
+   # define precise positioning (addition from the forum)
+   def lcd_display_string_pos(self, string, line, pos):
+    if line == 1:
+      pos_new = pos
+    elif line == 2:
+      pos_new = 0x40 + pos
+    elif line == 3:
+      pos_new = 0x14 + pos
+    elif line == 4:
+      pos_new = 0x54 + pos
+
+    self.lcd_write(0x80 + pos_new)
+
+    for char in string:
+      self.lcd_write(ord(char), Rs)
diff --git a/examples.py b/examples.py
@@ -0,0 +1,133 @@
+import RPi_I2C_driver
+from time import *
+
+mylcd = RPi_I2C_driver.lcd()
+# test 2
+mylcd.lcd_display_string("RPi I2C test", 1)
+mylcd.lcd_display_string(" Custom chars", 2)
+
+sleep(2) # 2 sec delay
+
+mylcd.lcd_clear()
+
+# let's define a custom icon, consisting of 6 individual characters
+# 3 chars in the first row and 3 chars in the second row
+fontdata1 = [
+        # Char 0 - Upper-left
+        [ 0x00, 0x00, 0x03, 0x04, 0x08, 0x19, 0x11, 0x10 ],
+        # Char 1 - Upper-middle
+        [ 0x00, 0x1F, 0x00, 0x00, 0x00, 0x11, 0x11, 0x00 ],
+        # Char 2 - Upper-right
+        [ 0x00, 0x00, 0x18, 0x04, 0x02, 0x13, 0x11, 0x01 ],
+        # Char 3 - Lower-left
+        [ 0x12, 0x13, 0x1b, 0x09, 0x04, 0x03, 0x00, 0x00 ],
+        # Char 4 - Lower-middle
+        [ 0x00, 0x11, 0x1f, 0x1f, 0x0e, 0x00, 0x1F, 0x00 ],
+        # Char 5 - Lower-right
+        [ 0x09, 0x19, 0x1b, 0x12, 0x04, 0x18, 0x00, 0x00 ],
+        # Char 6 - my test
+	[ 0x1f,0x0,0x4,0xe,0x0,0x1f,0x1f,0x1f],
+]
+
+# Load logo chars (fontdata1)
+mylcd.lcd_load_custom_chars(fontdata1)
+
+
+# Write first three chars to row 1 directly
+mylcd.lcd_write(0x80)
+mylcd.lcd_write_char(0)
+mylcd.lcd_write_char(1)
+mylcd.lcd_write_char(2)
+# Write next three chars to row 2 directly
+mylcd.lcd_write(0xC0)
+mylcd.lcd_write_char(3)
+mylcd.lcd_write_char(4)
+mylcd.lcd_write_char(5)
+sleep(2)
+
+mylcd.lcd_clear()
+
+mylcd.lcd_display_string_pos("Testing",1,1) # row 1, column 1
+sleep(1)
+mylcd.lcd_display_string_pos("Testing",2,3) # row 2, column 3
+sleep(1)
+mylcd.lcd_clear()
+
+# Now let's define some more custom characters
+fontdata2 = [
+        # Char 0 - left arrow
+        [ 0x1,0x3,0x7,0xf,0xf,0x7,0x3,0x1 ],
+        # Char 1 - left one bar 
+        [ 0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10 ],
+        # Char 2 - left two bars
+        [ 0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18 ],
+        # Char 3 - left 3 bars
+        [ 0x1c,0x1c,0x1c,0x1c,0x1c,0x1c,0x1c,0x1c ],
+        # Char 4 - left 4 bars
+        [ 0x1e,0x1e,0x1e,0x1e,0x1e,0x1e,0x1e,0x1e ],
+        # Char 5 - left start
+        [ 0x0,0x1,0x3,0x7,0xf,0x1f,0x1f,0x1f ],
+        # Char 6 - 
+        # [ ],
+]
+
+# Load logo chars from the second set
+mylcd.lcd_load_custom_chars(fontdata2)
+
+block = chr(255) # block character, built-in
+
+# display two blocks in columns 5 and 6 (i.e. AFTER pos. 4) in row 1
+# first draw two blocks on 5th column (cols 5 and 6), starts from 0
+mylcd.lcd_display_string_pos(block * 2,1,4)
+
+# 
+pauza = 0.2 # define duration of sleep(x)
+#
+# now draw cust. chars starting from col. 7 (pos. 6)
+
+pos = 6
+mylcd.lcd_display_string_pos(unichr(1),1,6)
+sleep(pauza)
+
+mylcd.lcd_display_string_pos(unichr(2),1,pos)
+sleep(pauza)
+
+mylcd.lcd_display_string_pos(unichr(3),1,pos)
+sleep(pauza)
+
+mylcd.lcd_display_string_pos(unichr(4),1,pos)
+sleep(pauza)
+
+mylcd.lcd_display_string_pos(block,1,pos)
+sleep(pauza)
+
+# and another one, same as above, 1 char-space to the right
+pos = pos +1 # increase column by one
+
+mylcd.lcd_display_string_pos(unichr(1),1,pos)
+sleep(pauza)
+mylcd.lcd_display_string_pos(unichr(2),1,pos)
+sleep(pauza)
+mylcd.lcd_display_string_pos(unichr(3),1,pos)
+sleep(pauza)
+mylcd.lcd_display_string_pos(unichr(4),1,pos)
+sleep(pauza)
+mylcd.lcd_display_string_pos(block,1,pos)
+sleep(pauza)
+
+
+#
+# now again load first set of custom chars - smiley
+mylcd.lcd_load_custom_chars(fontdata1)
+
+mylcd.lcd_display_string_pos(unichr(0),1,9)
+mylcd.lcd_display_string_pos(unichr(1),1,10)
+mylcd.lcd_display_string_pos(unichr(2),1,11)
+mylcd.lcd_display_string_pos(unichr(3),2,9)
+mylcd.lcd_display_string_pos(unichr(4),2,10)
+mylcd.lcd_display_string_pos(unichr(5),2,11)
+
+sleep(2)
+mylcd.lcd_clear()
+sleep(1)
+mylcd.backlight(0)