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import smbus
from time import *
# Older version of library that uses smbus, no longer updated
# For new projects use i2c_lcd
class i2c_lcd:
# Commands
CMD_Clear_Display = 0x01
CMD_Return_Home = 0x02
CMD_Entry_Mode = 0x04
CMD_Display_Control = 0x08
CMD_Cursor_Display_Shift = 0x10
CMD_Function_Set = 0x20
CMD_DDRAM_Set = 0x80
# Options
OPT_Increment = 0x02 # CMD_Entry_Mode
OPT_Display_Shift = 0x01 # CMD_Entry_Mode
OPT_Enable_Display = 0x04 # CMD_Display_Control
OPT_Enable_Cursor = 0x02 # CMD_Display_Control
OPT_Enable_Blink = 0x01 # CMD_Display_Control
OPT_Display_Shift = 0x08 # CMD_Cursor_Display_Shift
OPT_Shift_Right = 0x04 # CMD_Cursor_Display_Shift 0 = Left
OPT_2_Lines = 0x08 # CMD_Function_Set 0 = 1 line
OPT_5x10_Dots = 0x04 # CMD_Function_Set 0 = 5x7 dots
def __init__(self, addr, port, en, rw, rs, d4, d5, d6, d7, backlight = -1):
self.addr = addr
self.bus = smbus.SMBus(port)
self.en = en
self.rs = rs
self.rw = rw
self.d4 = d4
self.d5 = d5
self.d6 = d6
self.d7 = d7
self.backlight = backlight
self.backlight_state = False
# Activate LCD
initialize_i2c_data = 0x00
initialize_i2c_data = self._pinInterpret(self.d4, initialize_i2c_data, 0b1)
initialize_i2c_data = self._pinInterpret(self.d5, initialize_i2c_data, 0b1)
self._enable(initialize_i2c_data)
sleep(0.2)
self._enable(initialize_i2c_data)
sleep(0.1)
self._enable(initialize_i2c_data)
sleep(0.1)
# Initialize 4-bit mode
initialize_i2c_data = self._pinInterpret(self.d4, initialize_i2c_data, 0b0)
self._enable(initialize_i2c_data)
sleep(0.01)
self.command(self.CMD_Function_Set | self.OPT_2_Lines)
self.command(self.CMD_Display_Control | self.OPT_Enable_Display | self.OPT_Enable_Cursor)
self.command(self.CMD_Clear_Display)
self.command(self.CMD_Entry_Mode | self.OPT_Increment | self.OPT_Display_Shift)
def clear(self):
self.command(self.CMD_Clear_Display)
sleep(0.1)
def home(self):
self.command(self.CMD_Return_Home)
sleep(0.1)
def command(self, data):
self._write(data)
def setPosition(self, line, pos):
if line == 1:
address = pos
elif line == 2:
address = 0x40 + pos
elif line == 3:
address = 0x14 + pos
elif line == 4:
address = 0x54 + pos
self.command(self.CMD_DDRAM_Set + address)
def writeChar(self, char):
self._write(ord(char), False)
def writeString(self, string):
for c in string:
self.writeChar(c)
def backLightOn(self):
if self.backlight >= 0:
self.bus.write_byte(self.addr, self._pinInterpret(self.backlight, 0x00, 0b1))
self.backlight_state = True
def backLightOff(self):
if self.backlight >= 0:
self.bus.write_byte(self.addr, self._pinInterpret(self.backlight, 0x00, 0b0))
self.backlight_state = False
def _write(self, data, command=True):
i2c_data = 0x00
#Add data for high nibble
hi_nibble = data >> 4
i2c_data = self._pinInterpret(self.d4, i2c_data, (hi_nibble & 0x01))
i2c_data = self._pinInterpret(self.d5, i2c_data, ((hi_nibble >> 1) & 0x01))
i2c_data = self._pinInterpret(self.d6, i2c_data, ((hi_nibble >> 2) & 0x01))
i2c_data = self._pinInterpret(self.d7, i2c_data, ((hi_nibble >> 3) & 0x01))
# Set the register selector to 1 if this is data
if command != True:
i2c_data = self._pinInterpret(self.rs, i2c_data, 0x1)
# Toggle Enable
self._enable(i2c_data)
i2c_data = 0x00
#Add data for high nibble
low_nibble = data & 0x0F
i2c_data = self._pinInterpret(self.d4, i2c_data, (low_nibble & 0x01))
i2c_data = self._pinInterpret(self.d5, i2c_data, ((low_nibble >> 1) & 0x01))
i2c_data = self._pinInterpret(self.d6, i2c_data, ((low_nibble >> 2) & 0x01))
i2c_data = self._pinInterpret(self.d7, i2c_data, ((low_nibble >> 3) & 0x01))
# Set the register selector to 1 if this is data
if command != True:
i2c_data = self._pinInterpret(self.rs, i2c_data, 0x1)
self._enable(i2c_data)
sleep(0.01)
def _pinInterpret(self, pin, data, value="0b0"):
if value:
# Construct mask using pin
mask = 0x01 << (pin)
data = data | mask
else:
# Construct mask using pin
mask = 0x01 << (pin) ^ 0xFF
data = data & mask
return data
def _enable(self, data):
# Determine if black light is on and insure it does not turn off or on
if self.backlight_state:
data = self._pinInterpret(self.backlight, data, 0b1)
else:
data = self._pinInterpret(self.backlight, data, 0b0)
self.bus.write_byte(self.addr, data)
self.bus.write_byte(self.addr, self._pinInterpret(self.en, data, 0b1))
self.bus.write_byte(self.addr, data)