Hey Guys, Today we’re back again with another important tutorial on Raspberry Pi. Today we’ll interface I2C LCD with Raspberry Pi.
The common 16×2 Display usually used with the different projects can also be used with Raspberry Pi projects. Also in today’s article,
we’ll discuss various commands we use with the Python Module to make 16×2 display work via the I2C port on Raspberry Pi. So, let’s start today’s discussion. so , you can python too from this pyhton tutorial.
I2C 16×2 LCD
You’ll have use this LCD module either wither Arduino and NodeMCU Boards, might also with others. But to interface this with Raspberry Pi requires Python modules and code.
So, in order to make the display work like in Arduino Boards, we have to define certain modules.
This LCD has 13 pins out of which 7 pins are used for making communication with the microcontroller. But as this can reduce the availability of the pins on Raspberry Pi, ironically.
Or you can say that it can be a bit complicated in python to code the 7 pin communication to make LCD work.
So to ease this process,
we use I2C module for the 16×2 LCD. We can use Raspberry Pi I2C Port to make communicate with LCD and to make it work.
Make sure to power the module with 5V power pins as in some cases the LCD won’t work or may malfunction sometimes.
Also, the Address of the Module may differ, so make sure to check the address of the Address of the module.
Use sudo i2cdetect -y 1 command in the terminal to check the address of the display. Make sure to change the code in the Library below.
- Raspberry Pi with keyboard and mouse
- 16×2 LCD
- I2C module
- Jumper Wires
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Code & Modules
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(0x3f) # I2C module LCD 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 display_line(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 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 display(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)
Save this with LiquidCrystal_I2C.py
The commands mentioned below uses lcd (initialization object) as the prefix before . So, ignore this while writing your commands.
- lcd.clear() –> Clears the display
- lcd.display_line(“string”,y) –> Display string in the line number mentioned and continues to the next line
- lcd.backlight(state) –> Turns on backlight on or off, write either 0 or 1 in place of state
- lcd.display(“string”,y,x) –> Display the text on the position given in line y and place x
import LiquidCrystal_I2C from time import sleep lcd=LiquidCrystal_I2C.lcd() lcd.clear() lcd.display("Testing....",1,0) sleep(1) lcd.clear() for j in range(1,3): for i in range(16): lcd.display("*",j,i) sleep(0.1) lcd.clear() while True: try: lcd.display("Enter String you",1,0) lcd.display("want to display",2,0) sleep(1) lcd.display(input("Enter String You Want to Display"),1,0) sleep(2) lcd.clear() except KeyboardInterrupt: break
This is the test code for displaying text on display. With this, we have completed I2C LCD Raspberry Pi Tutorial. I hope you enjoyed it and if you find any of the issues, let me know in comment below.