Hey,
ich versuch schon seit einer Ewigkeit dieses Display über python anzusprechen: http://www.amazon.de/Display-Anzeigen-Zeichen-kompatibel-HD44780/dp/B00ALNHTVY/ref=sr_1_1?ie=UTF8&qid=1380988897&sr=8-1&keywords=display+20x4&tag=psblog-21 [Anzeige]
Dazu bin ich der Anleitung auf dieser Website gefolgt:
http://www.raspberrypi-spy.co.uk/2012/08/20x4-l…l-using-python/
Doch leider bekomme ich immer zuerst diese Fehlermeldungen wenn ich das script ausführe:
lcd.py:61: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
GPIO.setup(LCD_E, GPIO.OUT) # E
lcd.py:62: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
GPIO.setup(LCD_RS, GPIO.OUT) # RS
lcd.py:63: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
GPIO.setup(LCD_D4, GPIO.OUT) # DB4
lcd.py:64: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
GPIO.setup(LCD_D5, GPIO.OUT) # DB5
lcd.py:65: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
GPIO.setup(LCD_D6, GPIO.OUT) # DB6
lcd.py:66: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
GPIO.setup(LCD_D7, GPIO.OUT) # DB7
lcd.py:67: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
GPIO.setup(LED_ON, GPIO.OUT) # Backlight enable
backlight
text
Das Display hingegen leuchtet und mann kann auch weiße Kästchen erkennen. Jetzt zu meinem Quelltext:
(Hierbei verwende ich zum definieren von LCD_RS usw. immer die Nummer des Gpio Ports, also z.B. für gpio 7 die 26, weil ich das über nen einfaches script mit einer LED getest habe und ich nur so den gpio port ansprechen konnte, in der Anleitung hingegen werden immer die Nummern des Gpio Ports benutzt)
#!/usr/bin/python
#
# HD44780 20x4 LCD Test Script for
# Raspberry Pi
#
# Author : Matt Hawkins
# Site : http://www.raspberrypi-spy.co.uk/
#
# Date : 09/08/2012
#
# 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
import RPi.GPIO as GPIO
import time
# Define GPIO to LCD mapping
LCD_RS = 26
LCD_E = 24
LCD_D4 = 22
LCD_D5 = 18
LCD_D6 = 16
LCD_D7 = 12
LED_ON = 13
# Define some device constants
LCD_WIDTH = 20 # 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
LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line
# Timing constants
E_PULSE = 0.00005
E_DELAY = 0.00005
def main():
# Main program block
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_init()
# Toggle backlight off-on
GPIO.output(LED_ON, False)
time.sleep(1)
GPIO.output(LED_ON, True)
time.sleep(1)
print("backlight")
# Send some centred test
lcd_byte(LCD_LINE_1, LCD_CMD)
lcd_string("--------------------",2)
lcd_byte(LCD_LINE_2, LCD_CMD)
lcd_string("Rasbperry Pi",2)
lcd_byte(LCD_LINE_3, LCD_CMD)
lcd_string("Model B",2)
lcd_byte(LCD_LINE_4, LCD_CMD)
lcd_string("--------------------",2)
print("text")
time.sleep(3) # 3 second delay
lcd_byte(LCD_LINE_1, LCD_CMD)
lcd_string("Raspberrypi-spy",3)
lcd_byte(LCD_LINE_2, LCD_CMD)
lcd_string(".co.uk",3)
lcd_byte(LCD_LINE_3, LCD_CMD)
lcd_string("",2)
lcd_byte(LCD_LINE_4, LCD_CMD)
lcd_string("20x4 LCD Module Test",2)
time.sleep(20) # 20 second delay
# Blank display
lcd_byte(LCD_LINE_1, LCD_CMD)
lcd_string("",3)
lcd_byte(LCD_LINE_2, LCD_CMD)
lcd_string("",3)
lcd_byte(LCD_LINE_3, LCD_CMD)
lcd_string("",2)
lcd_byte(LCD_LINE_4, LCD_CMD)
lcd_string("",2)
time.sleep(3) # 3 second delay
# Turn off backlight
GPIO.output(LED_ON, False)
def lcd_init():
# 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),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()
Ich hoffe ihr könnt mir helfen