Created
August 6, 2013 17:17
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| #!/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 | |
| # | |
| from time import sleep | |
| from datetime import datetime | |
| from time import sleep | |
| class Adafruit_CharLCD: | |
| # 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, pin_rs=8, pin_e=10, pins_db=[11,12,13,15], 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.BOARD) | |
| 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() | |
| 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 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 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() | |
| def delayMicroseconds(self, microseconds): | |
| seconds = microseconds / float(1000000) # divide microseconds by 1 million for seconds | |
| sleep(seconds) | |
| 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 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) | |
| if __name__ == '__main__': | |
| lcd = Adafruit_CharLCD() | |
| lcd.noBlink() | |
| # lcd.clear() | |
| # lcd.message("Hello, Jessica!\nHow are you? .....abcdefghijg ") | |
| # lcd.scrollDisplayRight() | |
| while True: | |
| sleep(1) | |
| lcd.clear() | |
| lcd.message(datetime.now().strftime(' %I : %M : %S \n%a %b %d %Y')) |
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