179 lines
4.5 KiB
Python
179 lines
4.5 KiB
Python
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# -*- coding: utf-8 -*-
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# Original code found at:
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# https://gist.github.com/DenisFromHR/cc863375a6e19dce359d
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"""
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Compiled, mashed and generally mutilated 2014-2015 by Denis Pleic
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Made available under GNU GENERAL PUBLIC LICENSE
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# Modified Python I2C library for Raspberry Pi
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# as found on http://www.recantha.co.uk/blog/?p=4849
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# Joined existing 'i2c_lib.py' and 'lcddriver.py' into a single library
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# added bits and pieces from various sources
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# By DenisFromHR (Denis Pleic)
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# 2015-02-10, ver 0.1
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"""
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# i2c bus (0 -- original Pi, 1 -- Rev 2 Pi)
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I2CBUS = 0
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# LCD Address
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ADDRESS = 0x27
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import smbus
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from time import sleep
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class i2c_device:
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def __init__(self, addr, port=I2CBUS):
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self.addr = addr
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self.bus = smbus.SMBus(port)
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# Write a single command
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def write_cmd(self, cmd):
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self.bus.write_byte(self.addr, cmd)
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sleep(0.0001)
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# Write a command and argument
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def write_cmd_arg(self, cmd, data):
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self.bus.write_byte_data(self.addr, cmd, data)
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sleep(0.0001)
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# Write a block of data
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def write_block_data(self, cmd, data):
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self.bus.write_block_data(self.addr, cmd, data)
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sleep(0.0001)
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# Read a single byte
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def read(self):
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return self.bus.read_byte(self.addr)
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# Read
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def read_data(self, cmd):
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return self.bus.read_byte_data(self.addr, cmd)
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# Read a block of data
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def read_block_data(self, cmd):
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return self.bus.read_block_data(self.addr, cmd)
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# commands
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LCD_CLEARDISPLAY = 0x01
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LCD_RETURNHOME = 0x02
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LCD_ENTRYMODESET = 0x04
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LCD_DISPLAYCONTROL = 0x08
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LCD_CURSORSHIFT = 0x10
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LCD_FUNCTIONSET = 0x20
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LCD_SETCGRAMADDR = 0x40
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LCD_SETDDRAMADDR = 0x80
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# flags for display entry mode
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LCD_ENTRYRIGHT = 0x00
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LCD_ENTRYLEFT = 0x02
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LCD_ENTRYSHIFTINCREMENT = 0x01
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LCD_ENTRYSHIFTDECREMENT = 0x00
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# flags for display on/off control
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LCD_DISPLAYON = 0x04
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LCD_DISPLAYOFF = 0x00
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LCD_CURSORON = 0x02
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LCD_CURSOROFF = 0x00
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LCD_BLINKON = 0x01
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LCD_BLINKOFF = 0x00
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# flags for display/cursor shift
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LCD_DISPLAYMOVE = 0x08
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LCD_CURSORMOVE = 0x00
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LCD_MOVERIGHT = 0x04
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LCD_MOVELEFT = 0x00
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# flags for function set
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LCD_8BITMODE = 0x10
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LCD_4BITMODE = 0x00
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LCD_2LINE = 0x08
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LCD_1LINE = 0x00
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LCD_5x10DOTS = 0x04
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LCD_5x8DOTS = 0x00
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# flags for backlight control
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LCD_BACKLIGHT = 0x08
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LCD_NOBACKLIGHT = 0x00
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En = 0b00000100 # Enable bit
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Rw = 0b00000010 # Read/Write bit
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Rs = 0b00000001 # Register select bit
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class lcd:
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#initializes objects and lcd
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def __init__(self):
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self.lcd_device = i2c_device(ADDRESS)
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self.lcd_write(0x03)
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self.lcd_write(0x03)
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self.lcd_write(0x03)
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self.lcd_write(0x02)
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self.lcd_write(LCD_FUNCTIONSET | LCD_2LINE | LCD_5x8DOTS | LCD_4BITMODE)
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self.lcd_write(LCD_DISPLAYCONTROL | LCD_DISPLAYON)
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self.lcd_write(LCD_CLEARDISPLAY)
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self.lcd_write(LCD_ENTRYMODESET | LCD_ENTRYLEFT)
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sleep(0.2)
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# clocks EN to latch command
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def lcd_strobe(self, data):
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self.lcd_device.write_cmd(data | En | LCD_BACKLIGHT)
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sleep(.0005)
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self.lcd_device.write_cmd(((data & ~En) | LCD_BACKLIGHT))
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sleep(.0001)
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def lcd_write_four_bits(self, data):
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self.lcd_device.write_cmd(data | LCD_BACKLIGHT)
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self.lcd_strobe(data)
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# write a command to lcd
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def lcd_write(self, cmd, mode=0):
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self.lcd_write_four_bits(mode | (cmd & 0xF0))
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self.lcd_write_four_bits(mode | ((cmd << 4) & 0xF0))
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# write a character to lcd (or character rom) 0x09: backlight | RS=DR<
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# works!
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def lcd_write_char(self, charvalue, mode=1):
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self.lcd_write_four_bits(mode | (charvalue & 0xF0))
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self.lcd_write_four_bits(mode | ((charvalue << 4) & 0xF0))
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# put string function with optional char positioning
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def lcd_display_string(self, string, line=1, pos=0):
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if line == 1:
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pos_new = pos
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elif line == 2:
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pos_new = 0x40 + pos
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elif line == 3:
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pos_new = 0x14 + pos
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elif line == 4:
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pos_new = 0x54 + pos
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self.lcd_write(0x80 + pos_new)
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for char in string:
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self.lcd_write(ord(char), Rs)
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# clear lcd and set to home
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def lcd_clear(self):
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self.lcd_write(LCD_CLEARDISPLAY)
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self.lcd_write(LCD_RETURNHOME)
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# define backlight on/off (lcd.backlight(1); off= lcd.backlight(0)
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def backlight(self, state): # for state, 1 = on, 0 = off
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if state == 1:
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self.lcd_device.write_cmd(LCD_BACKLIGHT)
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elif state == 0:
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self.lcd_device.write_cmd(LCD_NOBACKLIGHT)
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# add custom characters (0 - 7)
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def lcd_load_custom_chars(self, fontdata):
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self.lcd_write(0x40);
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for char in fontdata:
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for line in char:
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self.lcd_write_char(line)
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