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Diffstat (limited to 'pyparallel/examples/lcd.py')
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1 files changed, 120 insertions, 0 deletions
diff --git a/pyparallel/examples/lcd.py b/pyparallel/examples/lcd.py new file mode 100644 index 0000000..b56c2a5 --- /dev/null +++ b/pyparallel/examples/lcd.py @@ -0,0 +1,120 @@ +#!/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) + +
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