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import smbus | |
import getopt | |
import sys | |
from time import * | |
from time import gmtime, strftime | |
# TODO: Factor out all device_write calls to some PCF8574 specific module ... | |
# will be different with another io expander | |
# communication from expander to display: high nibble first, then low nibble | |
# communication via i2c to the PCF 8547: bits are processed from highest to lowest (send P7 bit first) | |
# 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 ioexpander: | |
def __init__(self): | |
pass | |
class lcd: | |
#initializes objects and lcd | |
# LCD Commands | |
LCD_CLEARDISPLAY = 0x01 | |
LCD_RETURNHOME = 0x02 | |
LCD_ENTRYMODESET = 0x04 | |
LCD_DISPLAYCONTROL = 0x08 | |
LCD_CURSORSHIFT = 0x10 | |
LCD_FUNCTIONSET = 0x20 | |
LCD_SETCGRAMADDR = 0x40 | |
LCD_SETDDRAMADDR = 0x80 | |
# Flags for display on/off control | |
LCD_DISPLAYON = 0x04 | |
LCD_DISPLAYOFF = 0x00 | |
LCD_CURSORON = 0x02 | |
LCD_CURSOROFF = 0x00 | |
LCD_BLINKON = 0x01 | |
LCD_BLINKOFF = 0x00 | |
# Flags for display entry mode | |
LCD_ENTRYRIGHT = 0x00 | |
LCD_ENTRYLEFT = 0x02 | |
LCD_ENTRYSHIFTINCREMENT = 0x01 | |
LCD_ENTRYSHIFTDECREMENT = 0x00 | |
# Flags for display/cursor shift | |
LCD_DISPLAYMOVE = 0x08 | |
LCD_CURSORMOVE = 0x00 | |
LCD_MOVERIGHT = 0x04 | |
LCD_MOVELEFT = 0x00 | |
# flags for function set | |
LCD_8BITMODE = 0x10 | |
LCD_4BITMODE = 0x00 | |
LCD_2LINE = 0x08 | |
LCD_1LINE = 0x00 | |
LCD_5x10DOTS = 0x04 | |
LCD_5x8DOTS = 0x00 | |
# flags for backlight control | |
LCD_BACKLIGHT = 0x08 | |
LCD_NOBACKLIGHT = 0x00 | |
EN = 0b00000100 # Enable bit | |
RW = 0b00000010 # Read/Write bit | |
RS = 0b00000001 # Register select bit | |
''' | |
new pinout: | |
---------- | |
0x80 P7 - - D7 | |
0x40 P6 - - D6 | |
0x20 P5 - - D5 | |
0x10 P4 - - D4 | |
----------- | |
0x08 P3 - - BL Backlight ??? | |
0x04 P2 - - EN Starts Data read/write | |
0x02 P1 - - RW low: write, high: read | |
0x01 P0 - - RS Register Select: 0: Instruction Register (IR) (AC when read), 1: data register (DR) | |
''' | |
def __init__(self, addr, port, withBacklight=True, withOneTimeInit=False): | |
''' | |
device writes! | |
crosscheck also http://www.monkeyboard.org/tutorials/81-display/70-usb-serial-to-hd44780-lcd | |
here a sequence is listed | |
''' | |
self.displayshift = (self.LCD_CURSORMOVE | | |
self.LCD_MOVERIGHT) | |
self.displaymode = (self.LCD_ENTRYLEFT | | |
self.LCD_ENTRYSHIFTDECREMENT) | |
self.displaycontrol = (self.LCD_DISPLAYON | | |
self.LCD_CURSOROFF | | |
self.LCD_BLINKOFF) | |
if withBacklight: | |
self.blFlag=self.LCD_BACKLIGHT | |
else: | |
self.blFlag=self.LCD_NOBACKLIGHT | |
self.lcd_device = i2c_device(addr, port) | |
# we can initialize the display only once after it had been powered on | |
if(withOneTimeInit): | |
self.lcd_device.write(0x20) | |
self.lcd_strobe() | |
sleep(0.0100) # TODO: Not clear if we have to wait that long | |
self.lcd_write(self.LCD_FUNCTIONSET | self.LCD_4BITMODE | self.LCD_2LINE | self.LCD_5x8DOTS) # 0x28 | |
self.lcd_write(self.LCD_DISPLAYCONTROL | self.displaycontrol) # 0x08 + 0x4 = 0x0C | |
self.lcd_write(self.LCD_ENTRYMODESET | self.displaymode) # 0x06 | |
self.lcd_write(self.LCD_CLEARDISPLAY) # 0x01 | |
self.lcd_write(self.LCD_CURSORSHIFT | self.displayshift) # 0x14 | |
self.lcd_write(self.LCD_RETURNHOME) | |
# clocks EN to latch command | |
def lcd_strobe(self): | |
self.lcd_device.write((self.lcd_device.read() | self.EN | self.blFlag)) # | 0b0000 0100 # set "EN" high | |
self.lcd_device.write(( (self.lcd_device.read() | self.blFlag) & 0xFB)) # & 0b1111 1011 # set "EN" low | |
# write data to lcd in 4 bit mode, 2 nibbles | |
# high nibble is sent first | |
def lcd_write(self, cmd): | |
#write high nibble first | |
self.lcd_device.write( (cmd & 0xF0) | self.blFlag ) | |
hi= self.lcd_device.read() | |
self.lcd_strobe() | |
# write low nibble second ... | |
self.lcd_device.write( (cmd << 4) | self.blFlag ) | |
lo= self.lcd_device.read() | |
self.lcd_strobe() | |
self.lcd_device.write(self.blFlag) | |
# write a character to lcd (or character rom) 0x09: backlight | RS=DR | |
# works as expected | |
def lcd_write_char(self, charvalue): | |
controlFlag = self.blFlag | self.RS | |
# write high nibble | |
self.lcd_device.write((controlFlag | (charvalue & 0xF0))) | |
self.lcd_strobe() | |
# write low nibble | |
self.lcd_device.write((controlFlag | (charvalue << 4))) | |
self.lcd_strobe() | |
self.lcd_device.write(self.blFlag) | |
# put char function | |
def lcd_putc(self, char): | |
self.lcd_write_char(ord(char)) | |
def _setDDRAMAdress(self, line, col): | |
# we write to the Data Display RAM (DDRAM) | |
# TODO: Factor line offsets for other display organizations; this is for 20x4 only | |
if line == 1: | |
self.lcd_write(self.LCD_SETDDRAMADDR | (0x00 + col) ) | |
if line == 2: | |
self.lcd_write(self.LCD_SETDDRAMADDR | (0x40 + col) ) | |
if line == 3: | |
self.lcd_write(self.LCD_SETDDRAMADDR | (0x14 + col) ) | |
if line == 4: | |
self.lcd_write(self.LCD_SETDDRAMADDR | (0x54 + col) ) | |
# put string function | |
def lcd_puts(self, string, line): | |
self._setDDRAMAdress(line, 0) | |
for char in string: | |
self.lcd_putc(char) | |
# clear lcd and set to home | |
def lcd_clear(self): | |
# self.lcd_write(0x10) | |
self.lcd_write(self.LCD_CLEARDISPLAY) | |
# self.lcd_write(0x20) | |
self.lcd_write(self.LCD_RETURNHOME) | |
# 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) | |
# Let them know how it works | |
def usage(): | |
print 'Usage: lcdui.py --init --debug --backlightoff' | |
# Handle the command line arguments | |
def main(): | |
initFlag=False | |
debug=False | |
backlight=True | |
try: | |
opts, args = getopt.getopt(sys.argv[1:],"idb",["init","debug","backlightoff"]) | |
except getopt.GetoptError: | |
usage() | |
sys.exit(2) | |
for opt, arg in opts: | |
if opt == '-h': | |
usage() | |
sys.exit() | |
elif opt in ("-i", "--init"): | |
initFlag = True | |
elif opt in ("-d", "--debug"): | |
debug = True | |
elif opt in ("-b", "--backlightoff"): | |
backlight = False | |
if initFlag: | |
print "Doing initial init ..." | |
else: | |
print "Skipping init ..." | |
device = lcd(0x27,1,backlight, initFlag) | |
device.lcd_puts("01234567890123456789",1) | |
device.lcd_puts("012345 Zeile 2 56789",2) | |
device.lcd_puts("012345 Zeile 3 56789",3) | |
device.lcd_puts(strftime("%Y-%m-%d %H:%M:%S", gmtime()),4) | |
sleep(3) | |
device.lcd_clear() | |
device.lcd_puts(" Simple Clock ",1) | |
while True: | |
device.lcd_puts(strftime("%Y-%m-%d %H:%M:%S ", gmtime()),3) | |
sleep(1) | |
if __name__ == '__main__': | |
main() |
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