#!/usr/bin/python
# https://raspberrytips.nl/lcd-scherm-20×4-i2c-raspberry-pi/

import sys
import smbus
import time
import datetime
import subprocess

#I2C_ADDR = 0x3F # I2C device address
I2C_ADDR = 0x27 # I2C device address
LCD_WIDTH = 20 # Maximum characters per line

# Define some device constants
LCD_CHR = 1 # Mode – Sending data
LCD_CMD = 0 # Mode – Sending command

LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line
LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line

LCD_BACKLIGHT = 0x08 # On 0X08 / Off 0x00

ENABLE = 0b00000100 # Enable bit

E_PULSE = 0.0005
E_DELAY = 0.0005

bus = smbus.SMBus(1) # Rev 2 Pi uses 1

def run_cmd(cmd):
return subprocess.check_output(cmd, shell=True).decode(‘utf-8’)

def get_my_ipwlan():
val = run_cmd(“/sbin/ifconfig wlan0 | grep -w ‘inet’ |cut -c 14-28 | awk ‘{ print $1}'”)[:-1]
if val == “”:
val = “No connection!”
return val

def get_my_ipeth():
val = run_cmd(“/sbin/ifconfig enxb827eb62bee2 | /sbin/ifconfig enxb827eb62bee2 | grep -w ‘inet’ |cut -c 14-28 | awk ‘{ print $1}'”)[:-1]
if val == “”:
val = “No connection”
return val

def lcd_init():
lcd_byte(0x33,LCD_CMD) # 110011 Initialise
lcd_byte(0x32,LCD_CMD) # 110010 Initialise
lcd_byte(0x06,LCD_CMD) # 000110 Cursor move direction
lcd_byte(0x0C,LCD_CMD) # 001100 Display On,Cursor Off, Blink Off
lcd_byte(0x28,LCD_CMD) # 101000 Data length, number of lines, font size
lcd_byte(0x01,LCD_CMD) # 000001 Clear display
time.sleep(E_DELAY)

def lcd_byte(bits, mode):

bits_high = mode | (bits & 0xF0) | LCD_BACKLIGHT
bits_low = mode | ((bits<<4) & 0xF0) | LCD_BACKLIGHT

bus.write_byte(I2C_ADDR, bits_high)
lcd_toggle_enable(bits_high)

bus.write_byte(I2C_ADDR, bits_low)
lcd_toggle_enable(bits_low)

def lcd_toggle_enable(bits):
time.sleep(E_DELAY)
bus.write_byte(I2C_ADDR, (bits | ENABLE))
time.sleep(E_PULSE)
bus.write_byte(I2C_ADDR,(bits & ~ENABLE))
time.sleep(E_DELAY)

def lcd_string(message,line):

message = message.ljust(LCD_WIDTH," ")

lcd_byte(line, LCD_CMD)

for i in range(LCD_WIDTH):
lcd_byte(ord(message[i]),LCD_CHR)

def main():

lcd_init()

while True:

now = datetime.datetime.now()

lcd_string("PA0ESH-10 iGate APRX",LCD_LINE_1)
lcd_string( str(now.day)+'/'+str(now.month)+'/'+str(now.year)+' '+str(now.hour)+':'+str(now.minute),LCD_LINE_2)
lcd_string("W:{}".format(get_my_ipwlan()),LCD_LINE_3)
lcd_string("E:{}".format(get_my_ipeth()),LCD_LINE_4)
time.sleep(60)

if __name__ == '__main__':

try:
main()
except KeyboardInterrupt:
pass
finally:
lcd_byte(0x01, LCD_CMD)
root@hampi:/home/pi# ^C
root@hampi:/home/pi# nano lcd20x4.py

GNU nano 3.2 lcd20x4.py

lcd_init()

while True:

now = datetime.datetime.now()

lcd_string("MY OWN STRING",LCD_LINE_1)
lcd_string( str(now.day)+'/'+str(now.month)+'/'+str(now.year)+' '+str(now.hour)+':'+str(now.minute),LCD_LINE_2)
lcd_string("W:{}".format(get_my_ipwlan()),LCD_LINE_3)
lcd_string("E:{}".format(get_my_ipeth()),LCD_LINE_4)
time.sleep(60)

if __name__ == '__main__':

try:
main()
except KeyboardInterrupt:
pass
finally:
lcd_byte(0x01, LCD_CMD)

def get_my_ipwlan():
val = run_cmd(“/sbin/ifconfig wlan0 | grep ‘inet ‘ | cut -d: -f2 | awk ‘{ print $2}'”)[:-1]
if val == “”:
val = “No connection!”
return val

def get_my_ipeth():
val = run_cmd(“/sbin/ifconfig eth0 | grep ‘inet ‘ | cut -d: -f2 | awk ‘{ print $2}'”)[:-1]
if val == “”:
val = “No connection”
return val

De module is zichtbaar (3F) maar ik krijg geen tekst te zien op het display. Aangezien ik 2 ic2 en 2 displays heb en deze in alle combinaties heb geprobeerd is het hoogstwaarschijnlijk geen hardware probleem. Ik heb een Raspberry Pi 3B met Jessie. Enig idee waar dit aan kan liggen?

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