236 lines
7.3 KiB
Python
236 lines
7.3 KiB
Python
from time import sleep
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class Adafruit_CharLCD:
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# commands
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LCD_CLEARDISPLAY = 0x01
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LCD_RETURNHOME = 0x02
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LCD_ENTRYMODESET = 0x04
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LCD_DISPLAYCONTROL = 0x08
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LCD_CURSORSHIFT = 0x10
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LCD_FUNCTIONSET = 0x20
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LCD_SETCGRAMADDR = 0x40
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LCD_SETDDRAMADDR = 0x80
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# flags for display entry mode
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LCD_ENTRYRIGHT = 0x00
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LCD_ENTRYLEFT = 0x02
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LCD_ENTRYSHIFTINCREMENT = 0x01
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LCD_ENTRYSHIFTDECREMENT = 0x00
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# flags for display on/off control
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LCD_DISPLAYON = 0x04
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LCD_DISPLAYOFF = 0x00
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LCD_CURSORON = 0x02
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LCD_CURSOROFF = 0x00
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LCD_BLINKON = 0x01
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LCD_BLINKOFF = 0x00
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# flags for display/cursor shift
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LCD_DISPLAYMOVE = 0x08
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LCD_CURSORMOVE = 0x00
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# flags for display/cursor shift
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LCD_DISPLAYMOVE = 0x08
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LCD_CURSORMOVE = 0x00
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LCD_MOVERIGHT = 0x04
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LCD_MOVELEFT = 0x00
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# flags for function set
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LCD_8BITMODE = 0x10
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LCD_4BITMODE = 0x00
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LCD_2LINE = 0x08
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LCD_1LINE = 0x00
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LCD_5x10DOTS = 0x04
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LCD_5x8DOTS = 0x00
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def __init__(self, pin_rs=24, pin_e=23, pin_b=4, pins_db=[17, 25, 27, 22], GPIO=None):
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# Emulate the old behavior of using RPi.GPIO if we haven't been given
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# an explicit GPIO interface to use
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if not GPIO:
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import RPi.GPIO as GPIO
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self.GPIO = GPIO
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self.pin_rs = pin_rs
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self.pin_e = pin_e
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self.pin_b = pin_b
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self.pins_db = pins_db
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self.GPIO.setwarnings(False)
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self.GPIO.setmode(GPIO.BCM)
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self.GPIO.setup(self.pin_e, GPIO.OUT)
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self.GPIO.setup(self.pin_rs, GPIO.OUT)
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self.GPIO.setup(self.pin_b, GPIO.OUT)
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for pin in self.pins_db:
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self.GPIO.setup(pin, GPIO.OUT)
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self.GPIO.output(self.pin_b, True)
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self.write4bits(0x33) # initialization
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self.write4bits(0x32) # initialization
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self.write4bits(0x28) # 2 line 5x7 matrix
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self.write4bits(0x0C) # turn cursor off 0x0E to enable cursor
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self.write4bits(0x06) # shift cursor right
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self.displaycontrol = self.LCD_DISPLAYON | self.LCD_CURSOROFF | self.LCD_BLINKOFF
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self.displayfunction = self.LCD_4BITMODE | self.LCD_1LINE | self.LCD_5x8DOTS
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self.displayfunction |= self.LCD_2LINE
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""" Initialize to default text direction (for romance languages) """
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self.displaymode = self.LCD_ENTRYLEFT | self.LCD_ENTRYSHIFTDECREMENT
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self.write4bits(self.LCD_ENTRYMODESET |
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self.displaymode) # set the entry mode
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self.clear()
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def begin(self, cols, lines):
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if (lines > 1):
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self.numlines = lines
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self.displayfunction |= self.LCD_2LINE
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self.currline = 0
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def home(self):
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self.write4bits(self.LCD_RETURNHOME) # set cursor position to zero
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self.delayMicroseconds(3000) # this command takes a long time!
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def clear(self):
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self.write4bits(self.LCD_CLEARDISPLAY) # command to clear display
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# 3000 microsecond sleep, clearing the display takes a long time
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self.delayMicroseconds(3000)
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def setCursor(self, col, row):
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self.row_offsets = [0x00, 0x40, 0x14, 0x54]
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if (row > self.numlines):
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row = self.numlines - 1 # we count rows starting w/0
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self.write4bits(self.LCD_SETDDRAMADDR | (col + self.row_offsets[row]))
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def noDisplay(self):
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""" Turn the display off (quickly) """
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self.GPIO.output(self.pin_b, False)
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self.displaycontrol &= ~self.LCD_DISPLAYON
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self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)
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def display(self):
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""" Turn the display on (quickly) """
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self.GPIO.output(self.pin_b, True)
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self.displaycontrol |= self.LCD_DISPLAYON
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self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)
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def noCursor(self):
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""" Turns the underline cursor on/off """
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self.displaycontrol &= ~self.LCD_CURSORON
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self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)
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def cursor(self):
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""" Cursor On """
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self.displaycontrol |= self.LCD_CURSORON
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self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)
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def noBlink(self):
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""" Turn on and off the blinking cursor """
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self.displaycontrol &= ~self.LCD_BLINKON
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self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)
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def noBlink(self):
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""" Turn on and off the blinking cursor """
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self.displaycontrol &= ~self.LCD_BLINKON
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self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)
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def DisplayLeft(self):
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""" These commands scroll the display without changing the RAM """
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self.write4bits(self.LCD_CURSORSHIFT |
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self.LCD_DISPLAYMOVE | self.LCD_MOVELEFT)
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def scrollDisplayRight(self):
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""" These commands scroll the display without changing the RAM """
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self.write4bits(self.LCD_CURSORSHIFT |
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self.LCD_DISPLAYMOVE | self.LCD_MOVERIGHT)
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def leftToRight(self):
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""" This is for text that flows Left to Right """
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self.displaymode |= self.LCD_ENTRYLEFT
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self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)
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def rightToLeft(self):
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""" This is for text that flows Right to Left """
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self.displaymode &= ~self.LCD_ENTRYLEFT
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self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)
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def autoscroll(self):
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""" This will 'right justify' text from the cursor """
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self.displaymode |= self.LCD_ENTRYSHIFTINCREMENT
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self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)
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def noAutoscroll(self):
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""" This will 'left justify' text from the cursor """
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self.displaymode &= ~self.LCD_ENTRYSHIFTINCREMENT
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self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)
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def write4bits(self, bits, char_mode=False):
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""" Send command to LCD """
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self.delayMicroseconds(1000) # 1000 microsecond sleep
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bits = bin(bits)[2:].zfill(8)
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self.GPIO.output(self.pin_rs, char_mode)
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for pin in self.pins_db:
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self.GPIO.output(pin, False)
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for i in range(4):
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if bits[i] == "1":
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self.GPIO.output(self.pins_db[::-1][i], True)
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self.pulseEnable()
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for pin in self.pins_db:
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self.GPIO.output(pin, False)
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for i in range(4, 8):
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if bits[i] == "1":
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self.GPIO.output(self.pins_db[::-1][i-4], True)
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self.pulseEnable()
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def delayMicroseconds(self, microseconds):
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# divide microseconds by 1 million for seconds
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seconds = microseconds / float(1000000)
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sleep(seconds)
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def pulseEnable(self):
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self.GPIO.output(self.pin_e, False)
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# 1 microsecond pause - enable pulse must be > 450ns
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self.delayMicroseconds(1)
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self.GPIO.output(self.pin_e, True)
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# 1 microsecond pause - enable pulse must be > 450ns
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self.delayMicroseconds(1)
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self.GPIO.output(self.pin_e, False)
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self.delayMicroseconds(1) # commands need > 37us to settle
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def message(self, text):
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""" Send string to LCD. Newline wraps to second line"""
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for char in text:
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if char == '\n':
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self.write4bits(0xC0) # next line
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else:
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self.write4bits(ord(char), True)
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