import machine
from machine import Pin, SoftI2C
from lcd_api import LcdApi
from i2c_lcd import I2cLcd
import time 

I2C_ADDR = 0x27
totalRows = 2
totalColumns = 16

i2c = SoftI2C(scl=Pin(22), sda=Pin(21), freq=10000)     #initializing the I2C method for ESP32
#i2c = I2C(scl=Pin(5), sda=Pin(4), freq=10000)       #initializing the I2C method for ESP8266

lcd = I2cLcd(i2c, I2C_ADDR, totalRows, totalColumns)

while True:
    lcd.putstr("I2C LCD Tutorial")
    sleep(2)
    lcd.clear()
    lcd.putstr("Lets Count 0-10!")
    sleep(2)
    lcd.clear()
    for i in range(11):
        lcd.putstr(str(i))
        time.sleep(1)
        lcd.clear()


main.py

diagram.json

"""Proporciona una API para comunicarse con pantallas LCD de caracteres compatibles con HD44780."""

tiempo de importación

clase LcdApi:
    """Implementa la API para hablar con pantallas LCD de caracteres compatibles con HD44780.
    Esta clase sólo sabe qué comandos enviar a la pantalla LCD y no cómo obtenerlos.
    a la pantalla LCD.

    Se espera que una clase derivada implemente las funciones hal_xxx.
    """

    # Los siguientes nombres de constantes fueron extraídos de avrlib lcd.h
    # archivo de encabezado, sin embargo, cambié las definiciones de los números de bits
    # para morder máscaras.
    #
    # Conjunto de comandos del controlador LCD HD44780

    LCD_CLR = 0x01 # DB0: borrar pantalla
    LCD_HOME = 0x02 # DB1: regreso a la posición inicial

    LCD_ENTRY_MODE = 0x04 # DB2: establecer modo de entrada
    LCD_ENTRY_INC = 0x02 # --DB1: incremento
    LCD_ENTRY_SHIFT = 0x01 # --DB0: cambio

    LCD_ON_CTRL = 0x08 # DB3: enciende la pantalla LCD/cursor
    LCD_ON_DISPLAY = 0x04 # --DB2: enciende la pantalla
    LCD_ON_CURSOR = 0x02 # --DB1: activa el cursor
    LCD_ON_BLINK = 0x01 # --DB0: cursor parpadeante

    LCD_MOVE = 0x10 # DB4: mover cursor/visualizar
    LCD_MOVE_DISP = 0x08 # --DB3: mover pantalla (0-> mover cursor)
    LCD_MOVE_RIGHT = 0x04 # --DB2: mover a la derecha (0-> izquierda)

    LCD_FUNCTION = 0x20 # DB5: conjunto de funciones
    LCD_FUNCTION_8BIT = 0x10 # --DB4: configurar el modo 8BIT (modo 0->4BIT)
    LCD_FUNCTION_2LINES = 0x08 # --DB3: dos líneas (0->una línea)
    LCD_FUNCTION_10DOTS = 0x04 # --DB2: fuente 5x10 (0->fuente 5x7)
    LCD_FUNCTION_RESET = 0x30 # Consulte la sección "Inicialización mediante instrucción"

    LCD_CGRAM = 0x40 # DB6: establece la dirección RAM del CG
    LCD_DDRAM = 0x80 # DB7: establecer la dirección de DD RAM

    LCD_RS_CMD = 0
    LCD_RS_DATA = 1

    LCD_RW_WRITE = 0
    LCD_RW_READ = 1

    def __init__(self, núm_líneas, núm_columnas):
        self.num_lines = num_lines
        si self.num_lines > 4:
            self.num_lines = 4
        self.num_columns = num_columnas
        si self.num_columns > 40:
            self.num_columnas = 40
        self.cursor_x = 0
        self.cursor_y = 0
        self.implied_newline = Falso
        self.backlight = Verdadero
        self.display_off()
        self.backlight_on()
        auto.claro()
        self.hal_write_command(self.LCD_ENTRY_MODE | self.LCD_ENTRY_INC)
        self.hide_cursor()
        self.display_on()

    def claro(yo):
        """Borra la pantalla LCD y mueve el cursor hacia la parte superior izquierda
        esquina.
        """
        self.hal_write_command(self.LCD_CLR)
        self.hal_write_command(self.LCD_HOME)
        self.cursor_x = 0
        self.cursor_y = 0

    def mostrar_cursor(yo):
        """Hace que el cursor se haga visible."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
                               self.LCD_ON_CURSOR)

    def ocultar_cursor(yo):
        """Hace que el cursor quede oculto."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY)

    def parpadeo_cursor_on(yo):
        """Enciende el cursor y lo hace parpadear."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
                               self.LCD_ON_CURSOR | self.LCD_ON_BLINK)

    def parpadeo_cursor_off(yo):
        """Enciende el cursor y hace que no parpadee (es decir, que esté fijo)."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
                               self.LCD_ON_CURSOR)

    def display_on(yo):
        """Enciende (es decir, abre) la pantalla LCD."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY)

    def display_off(yo):
        """Apaga (es decir, deja en blanco) la pantalla LCD."""
        self.hal_write_command(self.LCD_ON_CTRL)

    def backlight_on(self):
        """Enciende la luz de fondo.

        Este no es realmente un comando LCD, pero algunos módulos tienen retroiluminación.
        controles, por lo que esto permite que hal pase a través del comando.
        """
        self.backlight = Verdadero
        self.hal_backlight_on()

    def retroiluminación_apagada(auto):
        """Apaga la luz de fondo.

        Este no es realmente un comando LCD, pero algunos módulos tienen retroiluminación.
        controles, por lo que esto permite que hal pase a través del comando.
        """
        self.backlight = Falso
        self.hal_backlight_off()

    def mover_a(self, cursor_x, cursor_y):
        """Mueve la posición del cursor a la posición indicada. El cursor
        la posición está basada en cero (es decir, cursor_x == 0 indica la primera columna).
        """
        self.cursor_x = cursor_x
        self.cursor_y = cursor_y
        dirección = cursor_x y 0x3f
        si cursor_y & 1:
            addr += 0x40 # Líneas 1 y 3 suman 0x40
        si cursor_y & 2: # Líneas 2 y 3 suman el número de columnas
            dirección += self.num_columns
        self.hal_write_command(self.LCD_DDRAM | dirección)

    def putchar(yo, char):
        """Escribe el carácter indicado en la pantalla LCD en el cursor actual
        posición y avanza el cursor una posición.
        """
        si carácter == '\n':
            si self.implied_newline:
                # self.implied_newline significa que avanzamos debido a un ajuste,
                # Entonces, si obtenemos una nueva línea justo después, la ignoramos.
                aprobar
            demás:
                self.cursor_x = self.num_columnas
        demás:
            self.hal_write_data(ord(char))
            self.cursor_x += 1
        si self.cursor_x >= self.num_columns:
            self.cursor_x = 0
            self.cursor_y += 1
            self.implied_newline = (char! = '\n')
        si self.cursor_y >= self.num_lines:
            self.cursor_y = 0
        self.move_to(self.cursor_x, self.cursor_y)

    def putstr(yo, cadena):
        """Escribe la cadena indicada en la pantalla LCD en el cursor actual
        posición y avanza la posición del cursor apropiadamente.
        """
        para char en cadena:
            self.putchar(char)

    def custom_char(self, ubicación, charmap):
        """Escribe un personaje en una de las 8 ubicaciones de CGRAM disponibles
        como chr(0) a chr(7).
        """
        ubicación &= 0x7
        self.hal_write_command(self.LCD_CGRAM | (ubicación << 3))
        self.hal_sleep_us(40)
        para i en el rango(8):
            self.hal_write_data(charmap[i])
            self.hal_sleep_us(40)
        self.move_to(self.cursor_x, self.cursor_y)

    def hal_backlight_on(yo):
        """Permite que la capa hal encienda la luz de fondo.

        Si lo desea, una clase HAL derivada implementará esta función.
        """
        aprobar

    def hal_backlight_off(yo):
        """Permite que la capa hal apague la luz de fondo.

        Si lo desea, una clase HAL derivada implementará esta función.
        """
        aprobar

    def hal_write_command(yo, cmd):
        """Escribe un comando en la pantalla LCD.

        Se espera que una clase HAL derivada implemente esto
        función.
        """
        generar error no implementado

    def hal_write_data(yo, datos):
        """Escribe datos en la pantalla LCD.

        Se espera que una clase HAL derivada implemente esto
        función.
        """
        generar error no implementado

    def hal_sleep_us(self, usecs):
        """Dormir durante algún tiempo (en microsegundos)."""
        tiempo.sleep_us(usecs)

lcd_api (1).py

import utime
import gc

from lcd_api import LcdApi
from machine import I2C

# PCF8574 pin definitions
MASK_RS = 0x01       # P0
MASK_RW = 0x02       # P1
MASK_E  = 0x04       # P2

SHIFT_BACKLIGHT = 3  # P3
SHIFT_DATA      = 4  # P4-P7

class I2cLcd(LcdApi):
    
    #Implements a HD44780 character LCD connected via PCF8574 on I2C

    def __init__(self, i2c, i2c_addr, num_lines, num_columns):
        self.i2c = i2c
        self.i2c_addr = i2c_addr
        self.i2c.writeto(self.i2c_addr, bytes([0]))
        utime.sleep_ms(20)   # Allow LCD time to powerup
        # Send reset 3 times
        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
        utime.sleep_ms(5)    # Need to delay at least 4.1 msec
        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
        utime.sleep_ms(1)
        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
        utime.sleep_ms(1)
        # Put LCD into 4-bit mode
        self.hal_write_init_nibble(self.LCD_FUNCTION)
        utime.sleep_ms(1)
        LcdApi.__init__(self, num_lines, num_columns)
        cmd = self.LCD_FUNCTION
        if num_lines > 1:
            cmd |= self.LCD_FUNCTION_2LINES
        self.hal_write_command(cmd)
        gc.collect()

    def hal_write_init_nibble(self, nibble):
        # Writes an initialization nibble to the LCD.
        # This particular function is only used during initialization.
        byte = ((nibble >> 4) & 0x0f) << SHIFT_DATA
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        gc.collect()
        
    def hal_backlight_on(self):
        # Allows the hal layer to turn the backlight on
        self.i2c.writeto(self.i2c_addr, bytes([1 << SHIFT_BACKLIGHT]))
        gc.collect()
        
    def hal_backlight_off(self):
        #Allows the hal layer to turn the backlight off
        self.i2c.writeto(self.i2c_addr, bytes([0]))
        gc.collect()
        
    def hal_write_command(self, cmd):
        # Write a command to the LCD. Data is latched on the falling edge of E.
        byte = ((self.backlight << SHIFT_BACKLIGHT) |
                (((cmd >> 4) & 0x0f) << SHIFT_DATA))
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        byte = ((self.backlight << SHIFT_BACKLIGHT) |
                ((cmd & 0x0f) << SHIFT_DATA))
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        if cmd <= 3:
            # The home and clear commands require a worst case delay of 4.1 msec
            utime.sleep_ms(5)
        gc.collect()

    def hal_write_data(self, data):
        # Write data to the LCD. Data is latched on the falling edge of E.
        byte = (MASK_RS |
                (self.backlight << SHIFT_BACKLIGHT) |
                (((data >> 4) & 0x0f) << SHIFT_DATA))
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        byte = (MASK_RS |
                (self.backlight << SHIFT_BACKLIGHT) |
                ((data & 0x0f) << SHIFT_DATA))      
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        gc.collect()

i2c_lcd (1).py

"""Provides an API for talking to HD44780 compatible character LCDs."""

import time

class LcdApi:
    """Implements the API for talking with HD44780 compatible character LCDs.
    This class only knows what commands to send to the LCD, and not how to get
    them to the LCD.

    It is expected that a derived class will implement the hal_xxx functions.
    """

    # The following constant names were lifted from the avrlib lcd.h
    # header file, however, I changed the definitions from bit numbers
    # to bit masks.
    #
    # HD44780 LCD controller command set

    LCD_CLR = 0x01              # DB0: clear display
    LCD_HOME = 0x02             # DB1: return to home position

    LCD_ENTRY_MODE = 0x04       # DB2: set entry mode
    LCD_ENTRY_INC = 0x02        # --DB1: increment
    LCD_ENTRY_SHIFT = 0x01      # --DB0: shift

    LCD_ON_CTRL = 0x08          # DB3: turn lcd/cursor on
    LCD_ON_DISPLAY = 0x04       # --DB2: turn display on
    LCD_ON_CURSOR = 0x02        # --DB1: turn cursor on
    LCD_ON_BLINK = 0x01         # --DB0: blinking cursor

    LCD_MOVE = 0x10             # DB4: move cursor/display
    LCD_MOVE_DISP = 0x08        # --DB3: move display (0-> move cursor)
    LCD_MOVE_RIGHT = 0x04       # --DB2: move right (0-> left)

    LCD_FUNCTION = 0x20         # DB5: function set
    LCD_FUNCTION_8BIT = 0x10    # --DB4: set 8BIT mode (0->4BIT mode)
    LCD_FUNCTION_2LINES = 0x08  # --DB3: two lines (0->one line)
    LCD_FUNCTION_10DOTS = 0x04  # --DB2: 5x10 font (0->5x7 font)
    LCD_FUNCTION_RESET = 0x30   # See "Initializing by Instruction" section

    LCD_CGRAM = 0x40            # DB6: set CG RAM address
    LCD_DDRAM = 0x80            # DB7: set DD RAM address

    LCD_RS_CMD = 0
    LCD_RS_DATA = 1

    LCD_RW_WRITE = 0
    LCD_RW_READ = 1

    def __init__(self, num_lines, num_columns):
        self.num_lines = num_lines
        if self.num_lines > 4:
            self.num_lines = 4
        self.num_columns = num_columns
        if self.num_columns > 40:
            self.num_columns = 40
        self.cursor_x = 0
        self.cursor_y = 0
        self.implied_newline = False
        self.backlight = True
        self.display_off()
        self.backlight_on()
        self.clear()
        self.hal_write_command(self.LCD_ENTRY_MODE | self.LCD_ENTRY_INC)
        self.hide_cursor()
        self.display_on()

    def clear(self):
        """Clears the LCD display and moves the cursor to the top left
        corner.
        """
        self.hal_write_command(self.LCD_CLR)
        self.hal_write_command(self.LCD_HOME)
        self.cursor_x = 0
        self.cursor_y = 0

    def show_cursor(self):
        """Causes the cursor to be made visible."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
                               self.LCD_ON_CURSOR)

    def hide_cursor(self):
        """Causes the cursor to be hidden."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY)

    def blink_cursor_on(self):
        """Turns on the cursor, and makes it blink."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
                               self.LCD_ON_CURSOR | self.LCD_ON_BLINK)

    def blink_cursor_off(self):
        """Turns on the cursor, and makes it no blink (i.e. be solid)."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
                               self.LCD_ON_CURSOR)

    def display_on(self):
        """Turns on (i.e. unblanks) the LCD."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY)

    def display_off(self):
        """Turns off (i.e. blanks) the LCD."""
        self.hal_write_command(self.LCD_ON_CTRL)

    def backlight_on(self):
        """Turns the backlight on.

        This isn't really an LCD command, but some modules have backlight
        controls, so this allows the hal to pass through the command.
        """
        self.backlight = True
        self.hal_backlight_on()

    def backlight_off(self):
        """Turns the backlight off.

        This isn't really an LCD command, but some modules have backlight
        controls, so this allows the hal to pass through the command.
        """
        self.backlight = False
        self.hal_backlight_off()

    def move_to(self, cursor_x, cursor_y):
        """Moves the cursor position to the indicated position. The cursor
        position is zero based (i.e. cursor_x == 0 indicates first column).
        """
        self.cursor_x = cursor_x
        self.cursor_y = cursor_y
        addr = cursor_x & 0x3f
        if cursor_y & 1:
            addr += 0x40    # Lines 1 & 3 add 0x40
        if cursor_y & 2:    # Lines 2 & 3 add number of columns
            addr += self.num_columns
        self.hal_write_command(self.LCD_DDRAM | addr)

    def putchar(self, char):
        """Writes the indicated character to the LCD at the current cursor
        position, and advances the cursor by one position.
        """
        if char == '\n':
            if self.implied_newline:
                # self.implied_newline means we advanced due to a wraparound,
                # so if we get a newline right after that we ignore it.
                pass
            else:
                self.cursor_x = self.num_columns
        else:
            self.hal_write_data(ord(char))
            self.cursor_x += 1
        if self.cursor_x >= self.num_columns:
            self.cursor_x = 0
            self.cursor_y += 1
            self.implied_newline = (char != '\n')
        if self.cursor_y >= self.num_lines:
            self.cursor_y = 0
        self.move_to(self.cursor_x, self.cursor_y)

    def putstr(self, string):
        """Write the indicated string to the LCD at the current cursor
        position and advances the cursor position appropriately.
        """
        for char in string:
            self.putchar(char)

    def custom_char(self, location, charmap):
        """Write a character to one of the 8 CGRAM locations, available
        as chr(0) through chr(7).
        """
        location &= 0x7
        self.hal_write_command(self.LCD_CGRAM | (location << 3))
        self.hal_sleep_us(40)
        for i in range(8):
            self.hal_write_data(charmap[i])
            self.hal_sleep_us(40)
        self.move_to(self.cursor_x, self.cursor_y)

    def hal_backlight_on(self):
        """Allows the hal layer to turn the backlight on.

        If desired, a derived HAL class will implement this function.
        """
        pass

    def hal_backlight_off(self):
        """Allows the hal layer to turn the backlight off.

        If desired, a derived HAL class will implement this function.
        """
        pass

    def hal_write_command(self, cmd):
        """Write a command to the LCD.

        It is expected that a derived HAL class will implement this
        function.
        """
        raise NotImplementedError

    def hal_write_data(self, data):
        """Write data to the LCD.

        It is expected that a derived HAL class will implement this
        function.
        """
        raise NotImplementedError

    def hal_sleep_us(self, usecs):
        """Sleep for some time (given in microseconds)."""
        time.sleep_us(usecs)