Class: I2C::Drivers::LCD::Display

Inherits:
Object
  • Object
show all
Defined in:
lib/i2c/drivers/lcd/display.rb

Overview

Driver class for the 2004/1602 I2C LCD Display.

forked from https://github.com/nerab/i2c-ss1602

see github.com/andec/i2c Parts copied from github.com/paulbarber/raspi-gpio/blob/master/lcd_display.py

Defined Under Namespace

Classes: BusDevice, Cursor

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(bus_or_bus_name, device_address, cols = 20, rows = 4, dotsize = 8) ⇒ Display

Returns a new instance of Display.



16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
 
# File 'lib/i2c/drivers/lcd/display.rb', line 16

def initialize(bus_or_bus_name, device_address, cols=20, rows=4, dotsize=8)
  if bus_or_bus_name.respond_to?(:write)
    @device = BusDevice.new(bus_or_bus_name, device_address)
  else
    @device = BusDevice.new(I2C.create(bus_or_bus_name), device_address)
  end

  @cols = cols
  @rows = rows
	  @dotsize = dotsize

  init_sequence

  @cursor = Cursor.new(self)
end

Instance Attribute Details

#cols ⇒ Object (readonly)

Returns the value of attribute cols.



14
15
16
 
# File 'lib/i2c/drivers/lcd/display.rb', line 14

def cols
  @cols
end

#cursor ⇒ Object (readonly)

Returns the value of attribute cursor.



14
15
16
 
# File 'lib/i2c/drivers/lcd/display.rb', line 14

def cursor
  @cursor
end

#device ⇒ Object (readonly)

Returns the value of attribute device.



14
15
16
 
# File 'lib/i2c/drivers/lcd/display.rb', line 14

def device
  @device
end

#rows ⇒ Object (readonly)

Returns the value of attribute rows.



14
15
16
 
# File 'lib/i2c/drivers/lcd/display.rb', line 14

def rows
  @rows
end

Instance Method Details

#backlight_off ⇒ Object 



71
72
73
 
# File 'lib/i2c/drivers/lcd/display.rb', line 71

def backlight_off
  device.write(FLAG_NOBACKLIGHT)
end

#backlight_on ⇒ Object 



67
68
69
 
# File 'lib/i2c/drivers/lcd/display.rb', line 67

def backlight_on
  device.write(FLAG_BACKLIGHT)
end

#clear ⇒ Object 



32
33
34
35
 
# File 'lib/i2c/drivers/lcd/display.rb', line 32

def clear
  write(COMMAND_CLEARDISPLAY)
  write(COMMAND_RETURNHOME)
end

#off ⇒ Object 



63
64
65
 
# File 'lib/i2c/drivers/lcd/display.rb', line 63

def off
  write(COMMAND_DISPLAYCONTROL | FLAG_DISPLAYOFF)
end

#on ⇒ Object 



59
60
61
 
# File 'lib/i2c/drivers/lcd/display.rb', line 59

def on
  write(COMMAND_DISPLAYCONTROL | FLAG_DISPLAYON)
end

#text(string, row, pad = false) ⇒ Object 



37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
 
# File 'lib/i2c/drivers/lcd/display.rb', line 37

def text(string, row, pad = false)
  case row
  when 0
    write(LCD_LINE_0)
  when 1
    write(LCD_LINE_1)
  when 2
    write(LCD_LINE_2)
  when 3
    write(LCD_LINE_3)
  else
    raise "Only rows #{0..(@rows - 1)} are supported"
  end

  # Right-pad with spaces so that the line only shows string
  string = sprintf('%-1$*2$s', string, @cols) if pad

  string.each_char do |c|
    write(c.ord, BIT_RS)
  end
end

#write(cmd, mode = 0) ⇒ Object

Send a low-level command to the display



78
79
80
81
 
# File 'lib/i2c/drivers/lcd/display.rb', line 78

def write(cmd, mode = 0)
  write_four_bits(mode | (cmd & 0xF0))
  write_four_bits(mode | ((cmd << 4) & 0xF0))
end