等待LCD1602准备好的代码

根据LCD1602的“忙”位状态，我们可以编写等待LCD1602准备好的代码。具体实现方法如下所示：

import RPi.GPIO as GPIO
import time

# 定义LCD1602的引脚
LCD_RS = 37
LCD_RW = 35
LCD_E = 33
LCD_D4 = 31
LCD_D5 = 29
LCD_D6 = 23
LCD_D7 = 21

# 初始化GPIO口
def init():
    GPIO.setwarnings(False)
    GPIO.setmode(GPIO.BOARD)
    GPIO.setup(LCD_RS, GPIO.OUT)
    GPIO.setup(LCD_RW, GPIO.OUT)
    GPIO.setup(LCD_E, GPIO.OUT)
    GPIO.setup(LCD_D4, GPIO.OUT)
    GPIO.setup(LCD_D5, GPIO.OUT)
    GPIO.setup(LCD_D6, GPIO.OUT)
    GPIO.setup(LCD_D7, GPIO.OUT)

# 发送指令到LCD1602
def send_command(command):
    GPIO.output(LCD_RS, GPIO.LOW)
    GPIO.output(LCD_RW, GPIO.LOW)
    GPIO.output(LCD_E, GPIO.HIGH)
    GPIO.output(LCD_D4, GPIO.HIGH if command & 0x10 else GPIO.LOW)
    GPIO.output(LCD_D5, GPIO.HIGH if command & 0x20 else GPIO.LOW)
    GPIO.output(LCD_D6, GPIO.HIGH if command & 0x40 else GPIO.LOW)
    GPIO.output(LCD_D7, GPIO.HIGH if command & 0x80 else GPIO.LOW)
    GPIO.output(LCD_E, GPIO.LOW)
    GPIO.output(LCD_E, GPIO.HIGH)
    GPIO.output(LCD_D4, GPIO.HIGH if command & 0x01 else GPIO.LOW)
    GPIO.output(LCD_D5, GPIO.HIGH if command & 0x02 else GPIO.LOW)
    GPIO.output(LCD_D6, GPIO.HIGH if command & 0x04 else GPIO.LOW)
    GPIO.output(LCD_D7, GPIO.HIGH if command & 0x08 else GPIO.LOW)
    GPIO.output(LCD_E, GPIO.LOW)

# 等待LCD1602准备好
def wait_for_ready():
    GPIO.setup(LCD_D7, GPIO.IN)
    GPIO.output(LCD_RS, GPIO.LOW)
    GPIO.output(LCD_RW, GPIO.HIGH)
    while GPIO.input(LCD_D7) == GPIO.HIGH:
        time.sleep(0.001)
    GPIO.setup(LCD_D7, GPIO.OUT)

# 初始化LCD1602
def init_lcd():
    send_command(0x38) # 8位数据接口，2行显示，5x7点阵字符
    send_command(0x08) # 关闭显示
    send_command(0x01) # 清屏
    send_command(0x06) # 光标右移，字符不移动
    send_command(0x0C) # 开启显示，不显示光标，不闪烁

# 主函数
if __name__ == '__main__':
    init()
    init_lcd()
    wait_for_ready()