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June 6, 2017 10:35
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#!/usr/bin/python | |
# | |
# The wiring for the LCD is as follows: | |
# 1 : GND | |
# 2 : 5V | |
# 3 : Contrast (0-5V)* | |
# 4 : RS (Register Select) | |
# 5 : R/W (Read Write) - GROUND THIS PIN | |
# 6 : Enable or Strobe | |
# 7 : Data Bit 0 - NOT USED | |
# 8 : Data Bit 1 - NOT USED | |
# 9 : Data Bit 2 - NOT USED | |
# 10: Data Bit 3 - NOT USED | |
# 11: Data Bit 4 | |
# 12: Data Bit 5 | |
# 13: Data Bit 6 | |
# 14: Data Bit 7 | |
# 15: LCD Backlight +5V** | |
# 16: LCD Backlight GND | |
import RPi.GPIO as GPIO | |
import time | |
from datetime import datetime | |
# Define GPIO to LCD mapping | |
LCD_RS = 26 | |
LCD_E = 19 | |
LCD_D4 = 13 | |
LCD_D5 = 6 | |
LCD_D6 = 5 | |
LCD_D7 = 11 | |
LED_ON = 15 | |
# Define some device constants | |
LCD_WIDTH = 16 # Maximum characters per line | |
LCD_CHR = True | |
LCD_CMD = False | |
LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line | |
LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line | |
# Timing constants | |
E_PULSE = 0.00005 | |
E_DELAY = 0.00005 | |
def main(): | |
lcd_init() | |
# Send some centred test | |
lcd_byte(LCD_LINE_1, LCD_CMD) | |
lcd_string("AquaControl", 2) | |
lcd_byte(LCD_LINE_2, LCD_CMD) | |
lcd_string("V 0.1", 2) | |
time.sleep(3) | |
lcd_byte(LCD_LINE_1, LCD_CMD) | |
lcd_string("Welcome to", 2) | |
lcd_byte(LCD_LINE_2, LCD_CMD) | |
lcd_string("auto aquarium", 2) | |
time.sleep(3) | |
lcd_byte(LCD_LINE_1, LCD_CMD) | |
lcd_string("AquaControl v0.1", 2) | |
while True: | |
now = datetime.now().strftime("%Y-%m-%d %H:%M") | |
lcd_byte(LCD_LINE_2, LCD_CMD) | |
lcd_string(now, 2) | |
time.sleep(1) | |
# Turn off backlight | |
#GPIO.output(LED_ON, False) | |
def lcd_init(): | |
GPIO.setmode(GPIO.BCM) # Use BCM GPIO numbers | |
GPIO.setup(LCD_E, GPIO.OUT) # E | |
GPIO.setup(LCD_RS, GPIO.OUT) # RS | |
GPIO.setup(LCD_D4, GPIO.OUT) # DB4 | |
GPIO.setup(LCD_D5, GPIO.OUT) # DB5 | |
GPIO.setup(LCD_D6, GPIO.OUT) # DB6 | |
GPIO.setup(LCD_D7, GPIO.OUT) # DB7 | |
GPIO.setup(LED_ON, GPIO.OUT) # Backlight enable | |
# Initialise display | |
lcd_byte(0x33,LCD_CMD) | |
lcd_byte(0x32,LCD_CMD) | |
lcd_byte(0x28,LCD_CMD) | |
lcd_byte(0x0C,LCD_CMD) | |
lcd_byte(0x06,LCD_CMD) | |
lcd_byte(0x01,LCD_CMD) | |
def lcd_string(message, style): | |
# Send string to display | |
# style = 1 Left justified | |
# style = 2 Centred | |
# style = 3 Right justified | |
if style == 1: | |
message = message.ljust(LCD_WIDTH, " ") | |
elif style == 2: | |
message = message.center(LCD_WIDTH, " ") | |
elif style == 3: | |
message = message.rjust(LCD_WIDTH, " ") | |
for i in range(LCD_WIDTH): | |
lcd_byte(ord(message[i]),LCD_CHR) | |
def lcd_byte(bits, mode): | |
# Send byte to data pins | |
# bits = data | |
# mode = True for character | |
# False for command | |
GPIO.output(LCD_RS, mode) # RS | |
# High bits | |
GPIO.output(LCD_D4, False) | |
GPIO.output(LCD_D5, False) | |
GPIO.output(LCD_D6, False) | |
GPIO.output(LCD_D7, False) | |
if bits&0x10==0x10: | |
GPIO.output(LCD_D4, True) | |
if bits&0x20==0x20: | |
GPIO.output(LCD_D5, True) | |
if bits&0x40==0x40: | |
GPIO.output(LCD_D6, True) | |
if bits&0x80==0x80: | |
GPIO.output(LCD_D7, True) | |
# Toggle 'Enable' pin | |
time.sleep(E_DELAY) | |
GPIO.output(LCD_E, True) | |
time.sleep(E_PULSE) | |
GPIO.output(LCD_E, False) | |
time.sleep(E_DELAY) | |
# Low bits | |
GPIO.output(LCD_D4, False) | |
GPIO.output(LCD_D5, False) | |
GPIO.output(LCD_D6, False) | |
GPIO.output(LCD_D7, False) | |
if bits&0x01==0x01: | |
GPIO.output(LCD_D4, True) | |
if bits&0x02==0x02: | |
GPIO.output(LCD_D5, True) | |
if bits&0x04==0x04: | |
GPIO.output(LCD_D6, True) | |
if bits&0x08==0x08: | |
GPIO.output(LCD_D7, True) | |
# Toggle 'Enable' pin | |
time.sleep(E_DELAY) | |
GPIO.output(LCD_E, True) | |
time.sleep(E_PULSE) | |
GPIO.output(LCD_E, False) | |
time.sleep(E_DELAY) | |
if __name__ == '__main__': | |
main() |
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