193 lines
4.9 KiB
Python
Executable File
193 lines
4.9 KiB
Python
Executable File
#!/usr/bin/python
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#
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# HD44780 LCD Test Script for
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# Raspberry Pi
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#
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# Original Author : Matt Hawkins
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# Site : http://www.raspberrypi-spy.co.uk
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# Modified to use PINS not BCM : Dave Conway-Jones
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#import
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import RPi.GPIO as GPIO
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import time
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import sys
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import os
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import select
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try:
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raw_input # Python 2
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except NameError:
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raw_input = input # Python 3
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# Turn off warnings if you run it a second time...
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GPIO.setwarnings(False)
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# Define initial Pins to LCD mapping
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LCD_RS = 26
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LCD_E = 24
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LCD_D4 = 22
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LCD_D5 = 18
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LCD_D6 = 16
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LCD_D7 = 12
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# Define some device constants
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LCD_WIDTH = 20 # Maximum characters per line
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LCD_CHR = True
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LCD_CMD = False
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LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
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LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line
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LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
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LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line
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# Timing constants
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E_PULSE = 0.0005
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E_DELAY = 0.0005
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def lcd_init():
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# Initialise display
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lcd_byte(0x33,LCD_CMD)
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lcd_byte(0x32,LCD_CMD)
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lcd_byte(0x0C,LCD_CMD)
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lcd_byte(0x06,LCD_CMD)
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lcd_byte(0x28,LCD_CMD)
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lcd_byte(0x01,LCD_CMD)
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time.sleep(E_DELAY)
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def lcd_string(message):
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# Send string to display
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message = message.ljust(LCD_WIDTH," ")
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for i in range(LCD_WIDTH):
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lcd_byte(ord(message[i]),LCD_CHR)
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def lcd_byte(bits, mode):
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# Send byte to data pins
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# bits = data
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# mode = True for character
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# False for command
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GPIO.output(LCD_RS, mode) # RS
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# High bits
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GPIO.output(LCD_D4, False)
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GPIO.output(LCD_D5, False)
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GPIO.output(LCD_D6, False)
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GPIO.output(LCD_D7, False)
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if bits&0x10==0x10:
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GPIO.output(LCD_D4, True)
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if bits&0x20==0x20:
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GPIO.output(LCD_D5, True)
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if bits&0x40==0x40:
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GPIO.output(LCD_D6, True)
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if bits&0x80==0x80:
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GPIO.output(LCD_D7, True)
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# Toggle 'Enable' pin
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time.sleep(E_DELAY)
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GPIO.output(LCD_E, True)
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time.sleep(E_PULSE)
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GPIO.output(LCD_E, False)
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time.sleep(E_DELAY)
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# Low bits
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GPIO.output(LCD_D4, False)
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GPIO.output(LCD_D5, False)
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GPIO.output(LCD_D6, False)
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GPIO.output(LCD_D7, False)
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if bits&0x01==0x01:
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GPIO.output(LCD_D4, True)
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if bits&0x02==0x02:
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GPIO.output(LCD_D5, True)
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if bits&0x04==0x04:
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GPIO.output(LCD_D6, True)
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if bits&0x08==0x08:
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GPIO.output(LCD_D7, True)
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# Toggle 'Enable' pin
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time.sleep(E_DELAY)
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GPIO.output(LCD_E, True)
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time.sleep(E_PULSE)
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GPIO.output(LCD_E, False)
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time.sleep(E_DELAY)
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# Main program loop
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if len(sys.argv) > 1:
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pins = sys.argv[1].lower().split(',')
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if len(pins) != 6:
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print("Bad number of pins supplied")
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print(" "+pins)
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sys.exit(0)
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LCD_RS = int(pins[0])
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LCD_E = int(pins[1])
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LCD_D4 = int(pins[2])
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LCD_D5 = int(pins[3])
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LCD_D6 = int(pins[4])
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LCD_D7 = int(pins[5])
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GPIO.setwarnings(False)
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GPIO.setmode(GPIO.BOARD) # Use GPIO BOARD numbers
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GPIO.setup(LCD_RS, GPIO.OUT) # RS
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GPIO.setup(LCD_E, GPIO.OUT) # E
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GPIO.setup(LCD_D4, GPIO.OUT) # DB4
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GPIO.setup(LCD_D5, GPIO.OUT) # DB5
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GPIO.setup(LCD_D6, GPIO.OUT) # DB6
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GPIO.setup(LCD_D7, GPIO.OUT) # DB7
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# Initialise display
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lcd_init()
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# Send some test
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lcd_byte(LCD_LINE_1, LCD_CMD)
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lcd_string("Node-RED")
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lcd_byte(LCD_LINE_2, LCD_CMD)
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lcd_string("LCD online")
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time.sleep(2) # 2 second delay
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lcd_byte(0x01,LCD_CMD)
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# Flush stdin so we start clean
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while len(select.select([sys.stdin.fileno()], [], [], 0.0)[0])>0:
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os.read(sys.stdin.fileno(), 4096)
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while True:
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try:
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data = raw_input()
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data = data.rstrip("\r\n\t")
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if data == "c:lose": # cleanup and exit
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GPIO.cleanup(LCD_RS)
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GPIO.cleanup(LCD_E)
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GPIO.cleanup(LCD_D4)
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GPIO.cleanup(LCD_D5)
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GPIO.cleanup(LCD_D6)
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GPIO.cleanup(LCD_D7)
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sys.exit(0)
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elif data == "clr:": # clear the display
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lcd_init()
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elif data.startswith("1:"):
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lcd_byte(LCD_LINE_1, LCD_CMD)
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lcd_string(data[2:])
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elif data.startswith("2:"):
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lcd_byte(LCD_LINE_2, LCD_CMD)
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lcd_string(data[2:])
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elif data.startswith("3:"):
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lcd_byte(LCD_LINE_3, LCD_CMD)
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lcd_string(data[2:])
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elif data.startswith("4:"):
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lcd_byte(LCD_LINE_4, LCD_CMD)
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lcd_string(data[2:])
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else: # default to line 1
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lcd_byte(LCD_LINE_1, LCD_CMD)
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lcd_string(data)
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except EOFError: # hopefully always caused by us sigint'ing the program
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GPIO.cleanup(LCD_RS)
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GPIO.cleanup(LCD_E)
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GPIO.cleanup(LCD_D4)
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GPIO.cleanup(LCD_D5)
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GPIO.cleanup(LCD_D6)
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GPIO.cleanup(LCD_D7)
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sys.exit(0)
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else:
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print("Bad params")
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print(" sudo nrlcd.py RS,E,D4,D5,D6,D7")
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sys.exit(0)
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