Adafruit_CharLCD.py

#!/usr/bin/python

#
# based on code from lrvick and LiquidCrystal
# lrvic - https://github.com/lrvick/raspi-hd44780/blob/master/hd44780.py
# LiquidCrystal - https://github.com/arduino/Arduino/blob/master/libraries/LiquidCrystal/LiquidCrystal.cpp
#

import time, smbus
import subprocess, datetime

class Adafruit_CharLCD_Virtual(object):
    # commands
    LCD_CLEARDISPLAY         = 0x01
    LCD_RETURNHOME         = 0x02
    LCD_ENTRYMODESET         = 0x04
    LCD_DISPLAYCONTROL         = 0x08
    LCD_CURSORSHIFT         = 0x10
    LCD_FUNCTIONSET         = 0x20
    LCD_SETCGRAMADDR         = 0x40
    LCD_SETDDRAMADDR         = 0x80

    # flags for display entry mode
    LCD_ENTRYRIGHT         = 0x00
    LCD_ENTRYLEFT         = 0x02
    LCD_ENTRYSHIFTINCREMENT     = 0x01
    LCD_ENTRYSHIFTDECREMENT     = 0x00

    # flags for display on/off control
    LCD_DISPLAYON         = 0x04
    LCD_DISPLAYOFF         = 0x00
    LCD_CURSORON         = 0x02
    LCD_CURSOROFF         = 0x00
    LCD_BLINKON         = 0x01
    LCD_BLINKOFF         = 0x00

    # flags for display/cursor shift
    LCD_DISPLAYMOVE         = 0x08
    LCD_CURSORMOVE         = 0x00

    # flags for display/cursor shift
    LCD_DISPLAYMOVE         = 0x08
    LCD_CURSORMOVE         = 0x00
    LCD_MOVERIGHT         = 0x04
    LCD_MOVELEFT         = 0x00

    # flags for function set
    LCD_8BITMODE         = 0x10
    LCD_4BITMODE         = 0x00
    LCD_2LINE             = 0x08
    LCD_1LINE             = 0x00
    LCD_5x10DOTS         = 0x04
    LCD_5x8DOTS         = 0x00


    def __init__(self):
       
        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()

    def begin(self, cols, lines):
        if (lines > 1):
            self.numlines = lines
            self.displayfunction |= self.LCD_2LINE
            self.currline = 0
            
    def home(self):
        self.write4bits(self.LCD_RETURNHOME) # set cursor position to zero
        self.delayMicroseconds(3000) # this command takes a long time!

    def clear(self):
        self.write4bits(self.LCD_CLEARDISPLAY) # command to clear display
        self.delayMicroseconds(3000)    # 3000 microsecond sleep, clearing the display takes a long time

    def setCursor(self, col, row):
        self.row_offsets = [ 0x00, 0x40, 0x14, 0x54 ]
    
        if ( row > self.numlines ): 
            row = self.numlines - 1 # we count rows starting w/0
    
        self.write4bits(self.LCD_SETDDRAMADDR | (col + self.row_offsets[row]))

    def noDisplay(self): 
        """ Turn the display off (quickly) """
        self.displaycontrol &= ~self.LCD_DISPLAYON
        self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)

    def display(self):
        """ Turn the display on (quickly) """
        self.displaycontrol |= self.LCD_DISPLAYON
        self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)

    def noCursor(self):
        """ Turns the underline cursor on/off """
        self.displaycontrol &= ~self.LCD_CURSORON
        self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)

    def cursor(self):
        """ Cursor On """
        self.displaycontrol |= self.LCD_CURSORON
        self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)

    def noBlink(self):
        """ Turn on and off the blinking cursor """
        self.displaycontrol &= ~self.LCD_BLINKON
        self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)

    def DisplayLeft(self):
        """ These commands scroll the display without changing the RAM """
        self.write4bits(self.LCD_CURSORSHIFT | self.LCD_DISPLAYMOVE | self.LCD_MOVELEFT)

    def scrollDisplayRight(self):
        """ These commands scroll the display without changing the RAM """
        self.write4bits(self.LCD_CURSORSHIFT | self.LCD_DISPLAYMOVE | self.LCD_MOVERIGHT);

    def leftToRight(self):
        """ This is for text that flows Left to Right """
        self.displaymode |= self.LCD_ENTRYLEFT
        self.write4bits(self.LCD_ENTRYMODESET | self.displaymode);

    def rightToLeft(self):
        """ This is for text that flows Right to Left """
        self.displaymode &= ~self.LCD_ENTRYLEFT
        self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)

    def autoscroll(self):
        """ This will 'right justify' text from the cursor """
        self.displaymode |= self.LCD_ENTRYSHIFTINCREMENT
        self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)

    def noAutoscroll(self): 
        """ This will 'left justify' text from the cursor """
        self.displaymode &= ~self.LCD_ENTRYSHIFTINCREMENT
        self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)

    def pulseEnable(self):
        pass

    def write4bits(self, bits, char_mode=False):
        """ Send command to LCD """
        pass
        
    def delayMicroseconds(self, microseconds):
        seconds = microseconds / float(1000000)    # divide microseconds by 1 million for seconds
        time.sleep(seconds)

    def message(self, text):
        """ Send string to LCD. Newline wraps to second line"""
        for char in text:
            if char == '\n':
                self.write4bits(0xC0) # next line
            else:
                self.write4bits(ord(char),True)



class Adafruit_CharLCD_GPIO(Adafruit_CharLCD_Virtual):

    def __init__(self, pin_rs=25, pin_e=24, pins_db=[23, 17, 27, 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
            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)
        
        super(Adafruit_CharLCD_GPIO, self).__init__()
        
    def pulseEnable(self):
        self.GPIO.output(self.pin_e, False)
        self.delayMicroseconds(1)       # 1 microsecond pause - enable pulse must be > 450ns 
        self.GPIO.output(self.pin_e, True)
        self.delayMicroseconds(1)       # 1 microsecond pause - enable pulse must be > 450ns 
        self.GPIO.output(self.pin_e, False)
        self.delayMicroseconds(1)       # commands need > 37us to settle

    def write4bits(self, bits, char_mode=False):
        """ Send command to LCD """
        self.delayMicroseconds(1000) # 1000 microsecond sleep
        bits=bin(bits)[2:].zfill(8)
        self.GPIO.output(self.pin_rs, char_mode)
        for pin in self.pins_db:
            self.GPIO.output(pin, False)
        for i in range(4):
            if bits[i] == "1":
                self.GPIO.output(self.pins_db[::-1][i], True)
        self.pulseEnable()
        for pin in self.pins_db:
            self.GPIO.output(pin, False)
        for i in range(4,8):
            if bits[i] == "1":
                self.GPIO.output(self.pins_db[::-1][i-4], True)
        self.pulseEnable()

        
# General i2c device class so that other devices can be added easily
class i2c_device:
    def __init__(self, addr, port):
        self.addr = addr
        self.bus = smbus.SMBus(port)
    
    def write(self, byte):
        self.bus.write_byte(self.addr, byte)
    
    def read(self):
        return self.bus.read_byte(self.addr)
    
    def read_nbytes_data(self, data, n): # For sequential reads > 1 byte
        return self.bus.read_i2c_block_data(self.addr, data, n)


class Adafruit_CharLCD_I2C_PCF8574(Adafruit_CharLCD_Virtual):
    """ Assumes PCF8574 port expander """
    """ data pins must be connected to P0..P3 of the port expander """

    def __init__(self, bus=1, device=0x20, bit_rs=4, bit_e=6):
        self.i2c = i2c_device(device, bus)
        
        # bit numbers on the I2C port expander
        self.bit_rs = 1 << bit_rs
        self.bit_e = 1 << bit_e
        
        super(Adafruit_CharLCD_I2C, self).__init__()
        
    def pulseEnable(self):
        self.i2c.write((self.i2c.read() & (~self.bit_e & 0xFF)))
        self.delayMicroseconds(1)        # 1 microsecond pause - enable pulse must be > 450ns 
        self.i2c.write((self.i2c.read() | self.bit_e))
        self.delayMicroseconds(1)        # 1 microsecond pause - enable pulse must be > 450ns 
        self.i2c.write((self.i2c.read() & (~self.bit_e & 0xFF)))
        self.delayMicroseconds(1)        # 1 microsecond pause - enable pulse must be > 450ns 

    def write4bits(self, bits, char_mode=False):
        """ Send command to LCD """
    
        self.delayMicroseconds(1000) # 1000 microsecond sleep
        
        if (char_mode):
            self.i2c.write(self.i2c.read() | self.bit_rs)
        else:
            self.i2c.write(self.i2c.read() & (~self.bit_rs & 0xFF))
        
        #print("0x%02X" % ((self.i2c.read() & 0xF0) | ((bits >> 4) & 0x0F)))
        self.i2c.write((self.i2c.read() & 0xF0) | ((bits >> 4) & 0x0F))
        self.pulseEnable()

        #print("0x%02X" % ((self.i2c.read() & 0xF0) | (bits & 0x0F)))
        self.i2c.write((self.i2c.read() & 0xF0) | (bits & 0x0F))
        self.pulseEnable()
        
        
def run_cmd(cmd):
    p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
    output = p.communicate()[0]
    return output

if __name__ == '__main__':
    lcd = Adafruit_CharLCD_I2C()
    cmd = "ip addr show wlan0 | grep inet | awk '{print $2}' | cut -d/ -f1"

    lcd.clear()
    #lcd.message("  Adafruit 16x2\n  Standard LCD")

    ipaddr = run_cmd(cmd)
    lcd.message(datetime.datetime.now().strftime('%b %d  %H:%M:%S\n'))
    lcd.message('IP %s' % ( ipaddr ) )