133 lines
3.7 KiB
Python
133 lines
3.7 KiB
Python
# Driver library for LCD display. Provided by Ryanteck LTD.
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# The procedures below can all be called in your own code!
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# You can just stick to the print string one though ;-)
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# This is the driver library for the LCD display
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# It contains some functions that you can call in your own program
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# Just remember that in order to use it you have to import it
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# You can do that with the line: import lcddriver
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# Make sure that lcddriver is in the same directory though!
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# Credit for this code goes to "natbett" of the Raspberry Pi Forum 18/02/13
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# Backlight: Enhanced by TOMDENKT - backlight control (on/off)
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# If lcddriver.py is NOT in same folder with your scripts,
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# set path to lcddriver IN YOUR script such as
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#import sys
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#sys.path.append("/home/pi/lcd") # example, path to lcddriver.py
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import i2c_lib
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from time import *
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# LCD Address
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# Usually you will have to use one of the two provided values below.
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# If you prefer, you can check your LCD address with the command: "sudo i2cdetect -y 1"
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# This is a common LCD address.
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ADDRESS = 0x27
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# This is another common LCD address.
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#ADDRESS = 0x3f
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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_lib.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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# put string function
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def lcd_display_string(self, string, line):
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if line == 1:
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self.lcd_write(0x80)
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if line == 2:
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self.lcd_write(0xC0)
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if line == 3:
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self.lcd_write(0x94)
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if line == 4:
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self.lcd_write(0xD4)
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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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# backlight control (on/off)
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# options: lcd_backlight(1) = ON, lcd_backlight(0) = OFF
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def lcd_backlight(self, state):
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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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