# -*- coding: utf-8 -*- """ Compiled, mashed and generally mutilated 2014-2015 by 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 A large amount of the code was included from Adafruit_CharLCDPlate """ # # 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) class lcd: # 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 # Offset for up to 4 rows. LCD_ROW_OFFSETS = (0x00, 0x40, 0x14, 0x54) # Line addresses for up to 4 line displays. Maps line number to DDRAM address for line. LINE_ADDRESSES = { 1: 0xC0, 2: 0x94, 3: 0xD4 } # Truncation constants for message function truncate parameter. NO_TRUNCATE = 0 TRUNCATE = 1 TRUNCATE_ELLIPSIS = 2 En = 0b00000100 # Enable bit Rw = 0b00000010 # Read/Write bit Rs = 0b00000001 # Register select bit #initializes objects and lcd def __init__(self): self.lcd_device = i2c_device(self.ADDRESS) # Initialize display control, function, and mode registers. self.displaycontrol = self.LCD_DISPLAYON | self.LCD_CURSOROFF | self.LCD_BLINKOFF self.displayfunction = self.LCD_4BITMODE | self.LCD_1LINE | self.LCD_2LINE | self.LCD_5x8DOTS self.displaymode = self.LCD_ENTRYLEFT | self.LCD_ENTRYSHIFTDECREMENT self.lcd_write(0x03) self.lcd_write(0x03) self.lcd_write(0x03) self.lcd_write(0x02) # Write registers. self.lcd_write(self.LCD_DISPLAYCONTROL | self.displaycontrol) self.lcd_write(self.LCD_FUNCTIONSET | self.displayfunction) self.lcd_write(self.LCD_ENTRYMODESET | self.displaymode) # set the entry mode sleep(0.2) # clocks EN to latch command def lcd_strobe(self, data): self.lcd_device.write_cmd(data | self.En | self.LCD_BACKLIGHT) sleep(.0005) self.lcd_device.write_cmd(((data & ~self.En) | self.LCD_BACKLIGHT)) sleep(.0001) def lcd_write_four_bits(self, data): self.lcd_device.write_cmd(data | self.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), self.Rs) # clear lcd and set to home def lcd_clear(self): self.lcd_write(self.LCD_CLEARDISPLAY) self.lcd_write(self.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(self.LCD_BACKLIGHT) elif state == 0: self.lcd_device.write_cmd(self.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), self.Rs) #============= from Adafruit_CharLCDPlate ======================= # Written by Adafruit Industries. MIT license. def begin(self, cols, lines): self.currline = 0 self.numlines = lines self.numcols = cols self.lcd_clear() def home(self): self.lcd_write(self.LCD_RETURNHOME) sleep(.3) # this command takes a long time! def message(self, text, truncate=NO_TRUNCATE): """ Send string to LCD. Newline wraps to second line""" lines = str(text).split('\n') # Split at newline(s) for i, line in enumerate(lines): # For each substring... address = self.LINE_ADDRESSES.get(i, None) if address is not None: # If newline(s), self.lcd_write(address) # set DDRAM address to line # Handle appropriate truncation if requested. linelen = len(line) if truncate == self.TRUNCATE and linelen > self.numcols: # Hard truncation of line. for char in line[0:self.numcols]: self.lcd_write(ord(char), self.Rs) elif truncate == self.TRUNCATE_ELLIPSIS and linelen > self.numcols: # Nicer truncation with ellipses. for char in (line[0:self.numcols-3] + '...'): self.lcd_write(ord(char), self.Rs) else: for char in line: self.lcd_write(ord(char), self.Rs)