usr/bin/disp

   1 #!/usr/bin/python
   2
   3 # modified version if this tutorial's demo script (German):
   4 # http://www.schnatterente.net/technik/raspberry-pi-32-zeichen-hitachi-hd44780-display
   5
   6 import time
   7 import sys
   8 import RPi.GPIO as GPIO
   9 GPIO.setwarnings(False)
  10
  11 # Zuordnung der GPIO Pins (ggf. anpassen)
  12 DISPLAY_RS = 7
  13 DISPLAY_E  = 8
  14 DISPLAY_DATA4 = 25
  15 DISPLAY_DATA5 = 24
  16 DISPLAY_DATA6 = 23
  17 DISPLAY_DATA7 = 18
  18
  19 DISPLAY_WIDTH = 16      # Zeichen je Zeile (colums per line)
  20 DISPLAY_LINE_1 = 0x80   # Adresse der ersten Display Zeile
  21 DISPLAY_LINE_2 = 0xC0
  22
  23 DISPLAY_CHR = True
  24 DISPLAY_CMD = False
  25 E_PULSE = 0.0005
  26 E_DELAY = 0.0005
  27
  28 def main():
  29         GPIO.setmode(GPIO.BCM)
  30         GPIO.setup(DISPLAY_E, GPIO.OUT)
  31         GPIO.setup(DISPLAY_RS, GPIO.OUT)
  32         GPIO.setup(DISPLAY_DATA4, GPIO.OUT)
  33         GPIO.setup(DISPLAY_DATA5, GPIO.OUT)
  34         GPIO.setup(DISPLAY_DATA6, GPIO.OUT)
  35         GPIO.setup(DISPLAY_DATA7, GPIO.OUT)
  36
  37         display_init()
  38
  39         # my screen is internally wired as a 2x8, so that's that bodge.
  40         if len (sys.argv) > 1:
  41                 mystring = sys.argv[1].ljust (8, " ")
  42                 lcd_byte (DISPLAY_LINE_1, DISPLAY_CMD)
  43                 lcd_string (mystring[0:8])
  44                 lcd_byte (DISPLAY_LINE_2, DISPLAY_CMD)
  45                 lcd_string (mystring[8:16])
  46
  47
  48 def display_init():
  49         lcd_byte(0x33,DISPLAY_CMD)
  50         lcd_byte(0x32,DISPLAY_CMD)
  51         lcd_byte(0x28,DISPLAY_CMD)
  52         lcd_byte(0x0C,DISPLAY_CMD)
  53         lcd_byte(0x06,DISPLAY_CMD)
  54         lcd_byte(0x01,DISPLAY_CMD)
  55
  56 def lcd_string(message):
  57         message = message.ljust(DISPLAY_WIDTH," ")
  58         for i in range(DISPLAY_WIDTH):
  59           lcd_byte(ord(message[i]),DISPLAY_CHR)
  60
  61 def lcd_byte(bits, mode):
  62         GPIO.output(DISPLAY_RS, mode)
  63         GPIO.output(DISPLAY_DATA4, False)
  64         GPIO.output(DISPLAY_DATA5, False)
  65         GPIO.output(DISPLAY_DATA6, False)
  66         GPIO.output(DISPLAY_DATA7, False)
  67         if bits&0x10==0x10:
  68           GPIO.output(DISPLAY_DATA4, True)
  69         if bits&0x20==0x20:
  70           GPIO.output(DISPLAY_DATA5, True)
  71         if bits&0x40==0x40:
  72           GPIO.output(DISPLAY_DATA6, True)
  73         if bits&0x80==0x80:
  74           GPIO.output(DISPLAY_DATA7, True)
  75         time.sleep(E_DELAY)
  76         GPIO.output(DISPLAY_E, True)
  77         time.sleep(E_PULSE)
  78         GPIO.output(DISPLAY_E, False)
  79         time.sleep(E_DELAY)
  80         GPIO.output(DISPLAY_DATA4, False)
  81         GPIO.output(DISPLAY_DATA5, False)
  82         GPIO.output(DISPLAY_DATA6, False)
  83         GPIO.output(DISPLAY_DATA7, False)
  84         if bits&0x01==0x01:
  85           GPIO.output(DISPLAY_DATA4, True)
  86         if bits&0x02==0x02:
  87           GPIO.output(DISPLAY_DATA5, True)
  88         if bits&0x04==0x04:
  89           GPIO.output(DISPLAY_DATA6, True)
  90         if bits&0x08==0x08:
  91           GPIO.output(DISPLAY_DATA7, True)
  92         time.sleep(E_DELAY)
  93         GPIO.output(DISPLAY_E, True)
  94         time.sleep(E_PULSE)
  95         GPIO.output(DISPLAY_E, False)
  96         time.sleep(E_DELAY)
  97
  98 if __name__ == '__main__':
  99         main()
 100