1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
#!/usr/bin/env python
# character LCD example for pyparallel
#
#(C) 2002 Chris Liechti <cliechti@gmx.net>
# this is distributed under a free software license, see license.txt
import sys, time
sys.path.append('..')
import parallel
LCDON = 0x01 #0x00000001 Switch on display
LCDOFF = 0x08 #0x00001000 Switch off display
LCDCLEAR = 0x01 #0x00000001
LCDLINE1 = 0x80 #0x10000000
LCDLINE2 = 0xc0 #0x11000000
LCDCURSORON = 0x0f #0x00001111 turn on cursor blinking
LCDCURSOROFF = 0x0c #0x00001100 Disable cursor blinking. The cursor is hidden.
LCDCGADRSET = 0x40 #0b01000000
LCDDDADRSET = 0x80 #0b10000000
LCD2LINES = 0x28 #0b00101000 Set display mode to two lines.
LCD8BITS = 0x30 #0b00110000 select 8 Bit interface
LCD4BITS = 0x20 #0b00100000 select 4 Bit interface
LCD_DATA_OFF = 0x05 #0x00000101 mask used to clear the data lines
LCD_RS = 1<<1
LCD_RW = 1<<2
LCD_E = 1<<3
LCD_D4 = 1<<4
LCD_D5 = 1<<5
LCD_D6 = 1<<6
LCD_D7 = 1<<7
class LCD:
def __init__(self):
self.p = parallel.Parallel()
self.data = 0
self.out(0) #reset pins
time.sleep(0.050) #wait more than 30ms
#send the reset sequece (3 times the same pattern)
self.out(LCD8BITS) #set 8 bit interface
self.toggleE() #toggle LCD_E, the enable pin
time.sleep(0.005) #wait a bit
self.toggleE() #toggle LCD_E, the enable pin
time.sleep(0.005) #wait a bit
self.toggleE() #toggle LCD_E, the enable pin
time.sleep(0.005) #wait a bit
self.out(LCD4BITS) #now set up the 4 bit interface
self.toggleE() #toggle LCD_E, the enable pin
time.sleep(0.002) #wait until instr is finished
self.instr(LCD2LINES) #set 2 lines display
self.instr(LCDCURSOROFF) #hide cursor
self.instr(LCDCLEAR) #clear display
#my connector has the wrong pinorder....
#better swap them in software than to solder ;-)
def reveseout(self, x):
r = ((x & (1<<0) and 1) << 7) |\
((x & (1<<1) and 1) << 6) |\
((x & (1<<2) and 1) << 5) |\
((x & (1<<3) and 1) << 4) |\
((x & (1<<4) and 1) << 3) |\
((x & (1<<5) and 1) << 2) |\
((x & (1<<6) and 1) << 1) |\
((x & (1<<7) and 1) << 0)
#print "%02x" % r, "%02x" %x
self.p.setData(r)
def toggleE(self):
"""toggle enable pin"""
self.data |= LCD_E; #toggle LCD_E, the enable pin
self.reveseout(self.data)
self.data &= ~LCD_E; #back to inactive position
self.reveseout(self.data)
def out(self, data):
"""set data to LCD port"""
self.data = data
self.reveseout(self.data)
def instr(self, cmd):
"""send instruction byte to LCD"""
self.out(cmd & 0xf0) #output upper nibble
self.toggleE() #toggle LCD_E, the enable pin
self.out((cmd << 4) & 0xf0) #and then the lower nibble
self.toggleE() #toggle LCD_E, the enable pin
time.sleep(0.001) #wait until instr is finished
def putc(self, c):
"""send a data byte to the LCD"""
c = ord(c)
self.out((c & 0xf0) | LCD_RS) #output upper nibble
self.toggleE() #toggle LCD_E, the enable pin
self.out(((c << 4) & 0xf0) | LCD_RS) #and then the lower nibble
self.toggleE() #toggle LCD_E, the enable pin
time.sleep(0.001) #wait until instr is finished
def write(self, str):
"""write a string to the LCD"""
for c in str:
self.putc(c) #write each character
def downloadFont(self, fontdata):
"""Set the memory pointer and download a font"""
self.instr(LCDCGADRSET);
self.write(fontdata)
self.instr(LCDLINE1) #just in case, set cursor to a visible pos
if __name__ == '__main__':
lcd = LCD()
lcd.write("Hello World")
lcd.instr(LCDLINE2)
lcd.write("from Python")
## for c in map(chr,range(256)):
## lcd.instr(LCDLINE1)
## lcd.write(c)
|
