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LCD scherm (16×2) via I2C backpack aansturen
#!/usr/bin/python
import smbus
import time
import datetime
I2C_ADDR = 0x27 # I2C device address
LCD_WIDTH = 16 # 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_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 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("RASPBERRYTIPS.NL",LCD_LINE_1)
lcd_string( str(now.hour) + ":" + str(now.minute) ,LCD_LINE_2)
time.sleep(1)
if __name__ == '__main__':
try:
main()
except KeyboardInterrupt:
pass
finally:
lcd_byte(0x01, LCD_CMD)
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