LCD LIB

SUBMITTED BY: bitcoinsachen

DATE: Dec. 20, 2016, 1:39 p.m.

FORMAT: Text only

SIZE: 2.7 kB

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  1. import smbus
  2. from time import *
  4. # General i2c device class so that other devices can be added easily
  5. class i2c_device:
  6. def __init__(self, addr, port):
  7. self.addr = addr
  8. self.bus = smbus.SMBus(port)
  10. def write(self, byte):
  11. self.bus.write_byte(self.addr, byte)
  13. def read(self):
  14. return self.bus.read_byte(self.addr)
  16. def read_nbytes_data(self, data, n): # For sequential reads > 1 byte
  17. return self.bus.read_i2c_block_data(self.addr, data, n)
  20. class lcd:
  21. #initializes objects and lcd
  22. '''
  23. Port definitions
  24. addr, en,rw,rs,d4,d5,d6,d7,bl
  25. 0x27, 2, 1, 0, 4, 5, 6, 7, 3
  26. '''
  27. def __init__(self, addr, port):
  28. self.lcd_device = i2c_device(addr, port)
  29. self.backlight=1; #default backlight on
  31. #set 4 bit mode
  32. self.lcd_device_writebl(0x20)
  33. self.lcd_strobe()
  34. sleep(0.0005)
  35. self.lcd_strobe()
  36. sleep(0.0005)
  37. self.lcd_strobe()
  38. sleep(0.0005)
  40. self.lcd_write(0x28)
  41. self.lcd_write(0x08)
  42. self.lcd_write(0x01)
  43. self.lcd_write(0x06)
  44. self.lcd_write(0x0C)
  45. self.lcd_write(0x0F)
  47. #wrapper to self.lcd_device.write for backlight control
  48. def lcd_device_writebl(self,value):
  49. if self.backlight:
  50. self.lcd_device.write(value | 0x08);
  51. else:
  52. self.lcd_device.write(value)
  54. # control backlight on=1 or off=0
  55. def lcd_backlight(self,on):
  56. self.backlight=on
  57. self.lcd_strobe()
  59. # clocks EN to latch command
  60. def lcd_strobe(self):
  61. #bit 2
  62. self.lcd_device_writebl((self.lcd_device.read() | 0x04))
  63. self.lcd_device_writebl((self.lcd_device.read() & 0xFB))
  65. # write a command to lcd
  66. def lcd_write(self, cmd):
  67. self.lcd_device_writebl((cmd >> 4)<<4)
  68. self.lcd_strobe()
  69. self.lcd_device_writebl((cmd & 0x0F)<<4)
  70. self.lcd_strobe()
  71. self.lcd_device_writebl(0x0)
  73. # write a character to lcd (or character rom)
  74. def lcd_write_char(self, charvalue):
  75. self.lcd_device_writebl((0x01 | (charvalue >> 4)<<4))
  76. self.lcd_strobe()
  77. self.lcd_device_writebl((0x01 | (charvalue & 0x0F)<<4))
  78. self.lcd_strobe()
  79. self.lcd_device_writebl(0x0)
  81. # put char function
  82. def lcd_putc(self, char):
  83. self.lcd_write_char(ord(char))
  85. # put string function
  86. def lcd_puts(self, string, line):
  87. if line == 1:
  88. self.lcd_write(0x80)
  89. if line == 2:
  90. self.lcd_write(0xC0)
  91. if line == 3:
  92. self.lcd_write(0x94)
  93. if line == 4:
  94. self.lcd_write(0xD4)
  96. for char in string:
  97. self.lcd_putc(char)
  99. # clear lcd and set to home
  100. def lcd_clear(self):
  101. self.lcd_write(0x1)
  102. self.lcd_write(0x2)
  104. # add custom characters (0 - 7)
  105. def lcd_load_custon_chars(self, fontdata):
  106. self.lcd_device.bus.write(0x40);
  107. for char in fontdata:
  108. for line in char:
  109. self.lcd_write_char(line)
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