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What it is

Pack of HD44780 lcd drivers to be used with Raspberry PI. It gives functions to quickly control what is displayed and how. Supports i2c, GPIO wiring and WiFi remote LCD.

Use two modes:

  • direct - write to lcd asap
  • buffered - write to buffer and do flush

Supports virtual lcds - ability to join few lcd into one

Supports 20x4, 16x2, 40x4 and so.

Include simple game Piader that utilize vlcds - demo

See more: koscis.wordpress.com

Content

LCDs

Class direct. Supports displaying chars on lcd. Using direct mode, means each char is displayed as soon as possible.

Class buffered. Use buffer to set what need to be displayed and flush function to draw on screen. Its drawing only those chars that differ from last frame.

Class virtual_direct. Allows to set virtual lcd. Rect area on any number of lcds. Uses direct mode

Class virtual_buffered. Allows to set virtual lcd. Rect area on any number of lcds. Uses buffered mode

Drivers

GPIO driver

Driver that use GPIO pins as connection to lcd. Default pins:

LCD : GPIO
RS  : 24
E   : 17
E2  : None
DB4 : 27
DB5 : 25
DB6 : 23
DB7 : 22

To use 40x4 lcd set E2

I2C driver

Use i2c bus to control lcd. Default connection:

GPIO :  PCF8574
GND  :  A0
GND  :  A1
GND  :  A2
GND  :  GND
+5V  :  Vcc
SDA  :  SDA
SCL  :  SCL

PCF8574  :   LCD
P4       :   LCD4 (RS)
P5       :   LCD6 (E)
P3       :   LCD14 (DB7)
P2       :   LCD13 (DB6)
P1       :   LCD12 (DB5)
P0       :   LCD11 (DB4)

WiFi direct driver

This one use UDP broadcast to transmit each command/char to remote LCD See here for NodeMCU remote LCD Articles

WiFi content driver

Sends UDP message with full content to remote LCD. See here for NodeMCU remote LCD Articles

Null and NullEvents driver

Used in tests

Wiring

GPIO 40x4

LCD13 [VSS] ------------ GND
LCD14 [VDD] ------------ +5V
LCD12 [V0] ------/\/\/\ [potentiometer]
                   \---- GND
LCD11 [RS] ------------- GPIO 25
LCD10 [R/W] ------------ GND
LCD9  [E1] ------------- GPIO 24
LCD15 [E2] ------------- GPIO 10
LCD4  [DB4] ------------ GPIO 22
LCD3  [DB5] ------------ GPIO 23
LCD2  [DB6] ------------ GPIO 27
LCD1  [DB7] ------------ GPIO 17
LCD17 [A] ------/\/\/\ [potentiometer]
                   \---- +5V
LCD18 [K] -------------- GND

GPIO 20x4, 16x2

LCD1 [VSS] ------------- GND
LCD2 [VDD] ------------- +5V
LCD3 [V0] ------/\/\/\ [potentiometer]
                   \---- GND
LCD4 [RS] -------------- GPIO 25
LCD5 [R/W] ------------- GND
LCD6 [E] --------------- GPIO 24
LCD7 [DB0]
LCD8 [DB1]
LCD9 [DB2]
LCD10 [DB3]
LCD11 [DB4] ------------ GPIO 22
LCD12 [DB5] ------------ GPIO 23
LCD13 [DB6] ------------ GPIO 27
LCD14 [DB7] ------------ GPIO 17
LCD15 [A] ------/\/\/\ [potentiometer]
                   \---- +5V
LCD16 [K] -------------- GND

I2C 20x4, 16x2

LCD                                           PCF8574
 1 -------- GND                     GND ----- A0   Vcc ---- +5V 
 2 -------- +5V                     GND ----- A1   SDA ---- SDA on RPi
 3 --/\/\ [potentiometer]           GND ----- A2   SCL ---- SCL on RPi
       \--- GND                   LCD11 ----- P0   INT 
 4 [RS]---- P4                    LCD12 ----- P1   P7
 5 -------- GND                   LCD13 ----- P2   P6
 6 [E]----- P5                    LCD14 ----- P3   P5 ----- LCD6
 7                                  GND ----- GND  P4 ----- LCD4
 8
 9
10
11 [DB4]--- P0
12 [DB5]--- P1
13 [DB6]--- P2
14 [DB7]--- P3
15 --/\/\ [potentiometer]
       \--- +5V
16 -------- GND

I2C 40x4

LCD                                           PCF8574
13 -------- GND                     GND ----- A0   Vcc ---- +5V 
14 -------- +5V                     GND ----- A1   SDA ---- SDA on RPi
12 --/\/\ [potentiometer]           GND ----- A2   SCL ---- SCL on RPi
       \--- GND                    LCD4 ----- P0   INT 
11 [RS]---- P4                     LCD3 ----- P1   P7
10 -------- GND                    LCD2 ----- P2   P6 ----- LCD15
 9 [E]----- P5                     LCD1 ----- P3   P5 ----- LCD9
15 [E2] --- P6                      GND ----- GND  P4 ----- LCD11
 4 [DB4]--- P0
 3 [DB5]--- P1
 2 [DB6]--- P2
 1 [DB7]--- P3
17 --/\/\ [potentiometer]
       \--- +5V
18 -------- GND

Usage

GPIO Driver

Simplest way

    l = lcd.CharLCD(20, 4, Gpio())

Plugin char display 20x4 on GPIO pins. Connections are default. Custom pins:

g = Gpio()
g.pins = {
    'RS': 24,
    'E': 17,
    'E2': None,
    'DB4': 27,
    'DB5': 25,
    'DB6': 23,
    'DB7': 22
}
l = lcd.CharLCD(20, 4, g)

Plug 40x4 by GPIO:

g = Gpio()
g.pins = {
    'RS': 24,
    'E': 17,
    'E2': 10,
    'DB4': 27,
    'DB5': 25,
    'DB6': 23,
    'DB7': 22
}
l = lcd.CharLCD(40, 4, g)

I2C Driver

    l = lcd.CharLCD(16, 2, I2C(0x20, 1))

Char display 16x2 on i2c @ 0x20 and bus 1. To change pins:

i2c = I2C(0x20, 1)
i2c.pins = {
    'RS': 4,
    'E': 5,
    'DB4': 0,
    'DB5': 1,
    'DB6': 2,
    'DB7': 3
}
l = lcd.CharLCD(16, 2, i2c)

Direct Class

Fully working demo (more in demos directory):

#!/usr/bin/python
# -*- coding: utf-8 -*-

"""test script for direct lcd input"""

__author__ = 'Bartosz Kościów'

import RPi.GPIO as GPIO #pylint: disable=I0011,F0401
from charlcd import direct as lcd
from charlcd.drivers.gpio import Gpio
from charlcd.drivers.i2c import I2C #pylint: disable=I0011,F0401

GPIO.setmode(GPIO.BCM)

def test2():
    """demo - 20x4 by gpio"""
    lcd_2 = lcd.CharLCD(20, 4, Gpio())
    lcd_2.init()
    lcd_2.write('-  Blarg !')
    lcd_2.write('-   Grarg !', 0, 1)
    lcd_2.set_xy(0, 2)
    lcd_2.write('-    ALIVE !!!!')
    lcd_2.stream('1234567890qwertyuiopasdfghjkl')

test2()

Functions

CharLCD(width, height, driver, cursor_visible=1, cursor_blink=1)

write(self, string, pos_x=None, pos_y=None) - print string on lcd

set_xy(pos_x, pos_y) - move cursor to position

stream(string) - stream string, breaks on line ends and after reaching end of display starts from top

Buffered Class

Fully working demo (more in demos directory):

#!/usr/bin/python
# -*- coding: utf-8 -*-

"""test script for buffered lcd"""

__author__ = 'Bartosz Kościów'

import RPi.GPIO as GPIO #pylint: disable=I0011,F0401
from charlcd import buffered as lcd
from charlcd.drivers.gpio import Gpio
from charlcd.drivers.i2c import I2C

GPIO.setmode(GPIO.BCM)

def test3():
    """demo 16x2"""
    lcd_1 = lcd.CharLCD(16, 2, I2C(0x20, 1), 0, 0)
    lcd_1.init()
    lcd_1.set_xy(10, 0)
    lcd_1.stream("1234567890qwertyuiopasdfghjkl")
    lcd_1.flush()


test3()

Functions

CharLCD(width, height, driver, cursor_visible=1, cursor_blink=1)

write(content, pos_x=None, pos_y=None) - writes content into buffer at position(x,y) or current

set_xy(pos_x, pos_y) - set cursor position

get_xy() - get cursor position

buffer_clear() - clears buffer

flush() - flush buffer to display

Shared functions

get_width() - display width

get_height() - display height

get_display_mode() - return direct or buffered

shutdown() - calls driver shutdown

Virtual Direct

#!/usr/bin/python
# -*- coding: utf-8 -*-

"""test script for virtual direct lcd"""

__author__ = 'Bartosz Kościów'

import RPi.GPIO as GPIO #pylint: disable=I0011,F0401
from charlcd import direct as lcd
from charlcd.drivers.gpio import Gpio
from charlcd.drivers.i2c import I2C #pylint: disable=I0011,F0401
from charlcd import virtual_direct as vlcd

GPIO.setmode(GPIO.BCM)


def test2():
    """demo: 16x2 + 20x4 = 36x4 left, right"""
    lcd_1 = lcd.CharLCD(16, 2, I2C(0x20, 1))
    lcd_2 = lcd.CharLCD(20, 4, Gpio(), 0, 0)
    lcd_1.init()
    lcd_2.init()
    vlcd_1 = vlcd.CharLCD(36, 4)
    vlcd_1.add_display(0, 0, lcd_2)
    vlcd_1.add_display(20, 0, lcd_1)
    vlcd_1.write('test me 123456789qwertyuiopasdfghjkl12')

test2()

Virtual Buffered

#!/usr/bin/python
# -*- coding: utf-8 -*-

"""test script for virtual buffered lcd"""

__author__ = 'Bartosz Kościów'

import RPi.GPIO as GPIO #pylint: disable=I0011,F0401
from charlcd import buffered as lcd
from charlcd.drivers.gpio import Gpio
from charlcd.drivers.i2c import I2C
from charlcd import virtual_buffered as vlcd

GPIO.setmode(GPIO.BCM)


def test1():
    """demo: 16x2 + 20x4 = 20x6"""
    lcd_1 = lcd.CharLCD(16, 2, I2C(0x20, 1))
    lcd_2 = lcd.CharLCD(20, 4, Gpio(), 0, 0)

    vlcd_1 = vlcd.CharLCD(20, 6)
    vlcd_1.add_display(0, 0, lcd_2)
    vlcd_1.add_display(0, 4, lcd_1)
    vlcd_1.init()

    vlcd_1.write('First line')
    vlcd_1.write('Second line', 0, 1)
    vlcd_1.write('Fifth Line', 0, 4)

    vlcd_1.set_xy(4, 2)
    vlcd_1.write('third line')

    vlcd_1.flush()

test1()

Functions

CharLCD(width, height, driver, cursor_visible=1, cursor_blink=1) - initialize, lcd size, cursor options

write(self, string, pos_x=None, pos_y=None) - print string on lcd

set_xy(pos_x, pos_y) - move cursor to position

get_xy() - get cursor position

stream(string) - stream string, breaks on line ends and after reaching end of display starts from top

buffer_clear() - clears buffer (only buffered)

flush() - flush buffer to display (only buffered)

get_width() - display width

get_height() - display height

get_display_mode() - return direct or buffered

shutdown() - calls driver shutdown

Handler

Handler for message_listener package. Supports three events: lcd.cmd, lcd.char and lcd.content.

Demos

Check charlcd/demos directory

Piader

This game is a simple demo. It show how to utilize any lcd to display a game.

It also shows how to generate a code with 2 fps :)

Controlls: a - left, d - right, space - fire

How to run:

First lets see a configuration with two lcds. One 20x4 and second 16x2. From this two vlcds are made. One 16x6 for game and 4x4 for score.

#!/usr/bin/python
# -*- coding: utf-8 -*-

"""Game launcher"""

__author__ = 'Bartosz Kościów'

import sys
sys.path.append("../")
import RPi.GPIO as GPIO #pylint: disable=I0011,F0401
from charlcd import buffered
from charlcd.drivers.gpio import Gpio
from charlcd.drivers.i2c import I2C
from charlcd import virtual_buffered
import piader_1_1.game as game

GPIO.setmode(GPIO.BCM)


def main():
    """set lcds and start game"""
    lcd_two = buffered.CharLCD(16, 2, I2C(0x20, 1), 0, 0)
    lcd_one = buffered.CharLCD(20, 4, Gpio(), 0, 0)

    vlcd_main = virtual_buffered.CharLCD(16, 6)
    vlcd_main.add_display(0, 0, lcd_one, 4, 0)
    vlcd_main.add_display(0, 4, lcd_two)
    vlcd_main.init()

    vlcd_support = virtual_buffered.CharLCD(4, 4)
    vlcd_support.add_display(0, 0, lcd_one)
    vlcd_support.init()

    my_game = game.Piader([vlcd_main, vlcd_support])
    my_game.game()


main()

Use 40x4 as game lcd:

drv = I2C(0x3a, 1)
drv.pins['E2'] = 6
lcd_three = buffered.CharLCD(40, 4, drv, 0, 0)
lcd_three.init()

my_game = game.Piader([lcd_three, None])

Use 20x4 as game lcd:

lcd_one.init()
my_game = game.Piader([lcd_one, None])

Class diagram

buffered.CharLCD  -->  lcd.CharLCD
                  -->  buffered_interface.Buffered

direct.CharLCD    -->  lcd.CharLCD
                  -->  direct_interface.Direct

virtual_buffered.CharLCD  -->  lcd.CharLCDVirtual  -->  lcd.CharLCD
                          -->  buffered_interface.Buffered

virtual_direct.CharLCD  -->  lcd.CharLCDVirtual  -->  lcd.CharLCD
                        -->  direct.Direct

gpio.Gpio --\
i2c.I2C   --->  base.BaseDriver
null.Null --/