raspberry pi 3 使用lcd1602

code:

import RPi.GPIO as GPIO
from random import sample
import string
import time


class LCD1602:
    # Define GPIO to LCD mapping
    LCD_RS = 14
    LCD_E = 15
    LCD_D4 = 17
    LCD_D5 = 18
    LCD_D6 = 27
    LCD_D7 = 22

    # Define some device constants
    LCD_WIDTH = 16  # Maximum characters per line
    LCD_CHR = True
    LCD_CMD = False

    LCD_LINE_1 = 0x80  # LCD RAM address for the 1st line
    LCD_LINE_2 = 0xC0  # LCD RAM address for the 2nd line

    # Timing constants
    E_PULSE = 0.0005
    E_DELAY = 0.0005

    def __init__(self):
        # Main program block
        GPIO.setwarnings(False)
        GPIO.setmode(GPIO.BCM)  # Use BCM GPIO numbers
        GPIO.setup(self.LCD_E, GPIO.OUT)  # E
        GPIO.setup(self.LCD_RS, GPIO.OUT)  # RS
        GPIO.setup(self.LCD_D4, GPIO.OUT)  # DB4
        GPIO.setup(self.LCD_D5, GPIO.OUT)  # DB5
        GPIO.setup(self.LCD_D6, GPIO.OUT)  # DB6
        GPIO.setup(self.LCD_D7, GPIO.OUT)  # DB7
        # Initialise display
        self.lcd_init()

    def lcd_init(self):
        # Initialise display
        self.lcd_byte(0x33, self.LCD_CMD)  # 110011 Initialise
        self.lcd_byte(0x32, self.LCD_CMD)  # 110010 Initialise
        self.lcd_byte(0x06, self.LCD_CMD)  # 000110 Cursor move direction
        self.lcd_byte(0x0C, self.LCD_CMD)  # 001100 Display On,Cursor Off, Blink Off
        self.lcd_byte(0x28, self.LCD_CMD)  # 101000 Data length, number of lines, font size
        self.lcd_byte(0x01, self.LCD_CMD)  # 000001 Clear display
        time.sleep(self.E_DELAY)

    def lcd_byte(self, bits, mode):
        # Send byte to data pins
        # bits = data
        # mode = True  for character
        #        False for command
        GPIO.output(self.LCD_RS, mode)  # RS
        # High bits
        GPIO.output(self.LCD_D4, False)
        GPIO.output(self.LCD_D5, False)
        GPIO.output(self.LCD_D6, False)
        GPIO.output(self.LCD_D7, False)
        if bits & 0x10 == 0x10:
            GPIO.output(self.LCD_D4, True)
        if bits & 0x20 == 0x20:
            GPIO.output(self.LCD_D5, True)
        if bits & 0x40 == 0x40:
            GPIO.output(self.LCD_D6, True)
        if bits & 0x80 == 0x80:
            GPIO.output(self.LCD_D7, True)

        # Toggle 'Enable' pin
        self.lcd_toggle_enable()

        # Low bits
        GPIO.output(self.LCD_D4, False)
        GPIO.output(self.LCD_D5, False)
        GPIO.output(self.LCD_D6, False)
        GPIO.output(self.LCD_D7, False)
        if bits & 0x01 == 0x01:
            GPIO.output(self.LCD_D4, True)
        if bits & 0x02 == 0x02:
            GPIO.output(self.LCD_D5, True)
        if bits & 0x04 == 0x04:
            GPIO.output(self.LCD_D6, True)
        if bits & 0x08 == 0x08:
            GPIO.output(self.LCD_D7, True)

        # Toggle 'Enable' pin
        self.lcd_toggle_enable()

    def lcd_toggle_enable(self):
        # Toggle enable
        time.sleep(self.E_DELAY)
        GPIO.output(self.LCD_E, True)
        time.sleep(self.E_PULSE)
        GPIO.output(self.LCD_E, False)
        time.sleep(self.E_DELAY)

    def lcd_string(self, message, line):
        # Send string to display
        message = message.ljust(self.LCD_WIDTH, " ")
        self.lcd_byte(line, self.LCD_CMD)
        for i in range(self.LCD_WIDTH):
            self.lcd_byte(ord(message[i]), self.LCD_CHR)


if __name__ == '__main__':
    a = LCD1602()
    while True:
        a.lcd_string(''.join(sample(string.ascii_letters, k=8)), a.LCD_LINE_1)
        a.lcd_string(''.join(sample(string.ascii_letters, k=8)), a.LCD_LINE_2)
        time.sleep(3)

参考代码