lms_testcom.py 文件源码

def __init__(self, lcd_address, lcd_width):
        # Define some device parameters

        self.I2C_ADDR  = lcd_address # 0x3f I2C device address 
                                     # To detect use sudo i2cdetect -y 0
                                     # or for RPi 2  sudo i2cdetect -y 1
        self.LCD_WIDTH = lcd_width   # 16 or 20 Maximum characters per line
        print ("class LCD " + str(lcd_width))    
        #LCD_WIDTH = 20 OR 16   # Maximum characters per line

        # Define some device constants
        self.LCD_CHR = 1 # Mode - Sending data
        self.LCD_CMD = 0 # Mode - Sending command

        self.LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
        self.LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line
        self.LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
        self.LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line

        self.LCD_BACKLIGHT  = 0x08  # On
        #LCD_BACKLIGHT = 0x00  # Off

        self.ENABLE = 0b00000100 # Enable bit

        # Timing constants
        self.E_PULSE = 0.0005
        self.E_DELAY = 0.0005

        #Open I2C interface
        self.bus = smbus.SMBus(0)  # Rev 1 Pi uses 0
        #bus = smbus.SMBus(1) # Rev 2 Pi uses 1

        #def lcd_init():
        # 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)