Posts by matthias250881

import smbus
from time import *


# General i2c device class so that other devices can be added easily
class i2c_device:
   def __init__(self, addr, port):
      self.addr = addr
      self.bus = smbus.SMBus(port)


   def write(self, byte):
      self.bus.write_byte(self.addr, byte)


   def read(self):
      return self.bus.read_byte(self.addr)


   def read_nbytes_data(self, data, n): # For sequential reads > 1 byte
      return self.bus.read_i2c_block_data(self.addr, data, n)




class lcd:
   #initializes objects and lcd
   '''
   pinout is as follows: PCF8574 - HD44780
   P0 - LCD11 - D4
   P1 - LCD12 - D5   
   P2 - LCD13 - D6
   P3 - LCD14 - D7   
   P4 - LCD4  - RS
   P5 - LCD5  - R/W   
   P6 - LCD6  - E   
   '''
   def __init__(self, addr, port):
      self.lcd_device = i2c_device(addr, port)
      self.lcd_device.write(0x03)
      self.lcd_strobe()
      sleep(0.0005)
      self.lcd_strobe()
      sleep(0.0005)
      self.lcd_strobe()
      sleep(0.0005)
      self.lcd_device.write(0x02)
      self.lcd_strobe()
      sleep(0.0005)


      self.lcd_write(0x28)
      self.lcd_write(0x08)
      self.lcd_write(0x01)
      self.lcd_write(0x06)
      self.lcd_write(0x0C)


      self.lcd_write(0x0F)


   # clocks EN to latch command
   def lcd_strobe(self):
      self.lcd_device.write((self.lcd_device.read() | 0x40))
      self.lcd_device.write((self.lcd_device.read() & 0xbF))


   # write a command to lcd
   def lcd_write(self, cmd):
      self.lcd_device.write((cmd >> 4))
      hi= self.lcd_device.read()
      self.lcd_strobe()
      self.lcd_device.write((cmd & 0x0F))
      lo= self.lcd_device.read()
      self.lcd_strobe()
      self.lcd_device.write(0x0)
   #   print 'cmd',cmd,hi,lo


   # write a character to lcd (or character rom)
   def lcd_write_char(self, charvalue):
   #      print "char",charvalue
         self.lcd_device.write((0x10 | (charvalue >> 4)))
         self.lcd_strobe()
         self.lcd_device.write((0x10 | (charvalue & 0x0F)))
         self.lcd_strobe()
         self.lcd_device.write(0x0)


   # put char function
   def lcd_putc(self, char):
      self.lcd_write_char(ord(char))


   # put string function
   def lcd_puts(self, string, line):
      if line == 1:
         self.lcd_write(0x10)
      if line == 2:
         self.lcd_write(0xC0)
      if line == 3:
         self.lcd_write(0x94)
      if line == 4:
         self.lcd_write(0xD4)


      for char in string:
         self.lcd_putc(char)


   # clear lcd and set to home
   def lcd_clear(self):
      self.lcd_write(0x1)
      self.lcd_write(0x2)


   # add custom characters (0 - 7)
   def lcd_load_custon_chars(self, fontdata):
      self.lcd_device.bus.write(0x40);
      for char in fontdata:
         for line in char:
            self.lcd_write_char(line)