shutdown.py 文件源码

def __init__(self, pin_rs=25, pin_e=24, pins_db=[23, 17, 21, 22], GPIO=None):
        # Emulate the old behavior of using RPi.GPIO if we haven't been given
        # an explicit GPIO interface to use
        if not GPIO:
            import RPi.GPIO as GPIO
            GPIO.setwarnings(False)
        self.GPIO = GPIO
        self.pin_rs = pin_rs
        self.pin_e = pin_e
        self.pins_db = pins_db

        self.GPIO.setmode(GPIO.BCM)
        self.GPIO.setup(self.pin_e, GPIO.OUT)
        self.GPIO.setup(self.pin_rs, GPIO.OUT)

        for pin in self.pins_db:
            self.GPIO.setup(pin, GPIO.OUT)

        self.write4bits(0x33)  # initialization
        self.write4bits(0x32)  # initialization
        self.write4bits(0x28)  # 2 line 5x7 matrix
        self.write4bits(0x0C)  # turn cursor off 0x0E to enable cursor
        self.write4bits(0x06)  # shift cursor right

        self.displaycontrol = self.LCD_DISPLAYON | self.LCD_CURSOROFF | self.LCD_BLINKOFF

        self.displayfunction = self.LCD_4BITMODE | self.LCD_1LINE | self.LCD_5x8DOTS
        self.displayfunction |= self.LCD_2LINE

        # Initialize to default text direction (for romance languages)
        self.displaymode = self.LCD_ENTRYLEFT | self.LCD_ENTRYSHIFTDECREMENT
        self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)  # set the entry mode

        self.clear()