Adafruit Raspberry Pi 16x2 Character LCD Plate module
This module allows you to use Adafruit's 16x2 Character LCD Plate for Raspberry Pi with the pyboard, the code is basically a direct translation of Adafruit's opensource Raspberry Pi CPython source into uPy, which has a different approach to I2C.
usage
... err sorry ... will update this later, wrote this module some time ago and now have to work out which pins on the plate are for I2C and the backlight ... shouldn't be too difficult in the meantime to work it through if you have one of these plates (check the schematic - taking the plate out to a bread board using an Adafruit Pi Cobbler cable makes things easier.
known limitations
- don't seem to be able to read the input buttons on the Char LCD Plate
the module
charlcdplate.py
import pyb
class CharLCDPlate():
MCP23017_IOCON_BANK0 = 0x0A
MCP23017_IOCON_BANK1 = 0x15
MCP23017_GPIOA = 0x09
MCP23017_IODIRB = 0x10
MCP23017_GPIOB = 0x19
SELECT = 0
RIGHT = 1
DOWN = 2
UP = 3
LEFT = 4
OFF = 0x00
RED = 0x01
GREEN = 0x02
BLUE = 0x04
YELLOW = RED + GREEN
TEAL = GREEN + BLUE
VIOLET = RED + BLUE
WHITE = RED + GREEN + BLUE
ON = RED + GREEN + BLUE
LCD_CLEARDISPLAY = 0x01
LCD_RETURNHOME = 0x02
LCD_ENTRYMODESET = 0x04
LCD_DISPLAYCONTROL = 0x08
LCD_CURSORSHIFT = 0x10
LCD_FUNCTIONSET = 0x20
LCD_SETCGRAMADDR = 0x40
LCD_SETDDRAMADDR = 0x80
LCD_DISPLAYON = 0x04
LCD_DISPLAYOFF = 0x00
LCD_CURSORON = 0x02
LCD_CURSOROFF = 0x00
LCD_BLINKON = 0x01
LCD_BLINKOFF = 0x00
LCD_ENTRYRIGHT = 0x00
LCD_ENTRYLEFT = 0x02
LCD_ENTRYSHIFTINCREMENT = 0x01
LCD_ENTRYSHIFTDECREMENT = 0x00
LCD_DISPLAYMOVE = 0x08
LCD_CURSORMOVE = 0x00
LCD_MOVERIGHT = 0x04
LCD_MOVELEFT = 0x00
def __init__(self, busnum, addr):
self.i2c = pyb.I2C(busnum,pyb.I2C.MASTER)
self.address = addr
self.porta, self.portb, self.ddrb = 0, 0, 0b00010000
self.i2c.mem_write(0,self.address,self.MCP23017_IOCON_BANK1)
registers =[ 0b00111111, self.ddrb, 0b00111111, 0b00000000, 0b00000000, 0b00000000, 0b00000000,
0b00000000, 0b00000000, 0b00000000, 0b00000000, 0b00000000, 0b00111111, 0b00000000,
0b00000000, 0b00000000, 0b00000000, 0b00000000, self.porta, self.portb, self.porta,
self.portb ]
for register in registers:
self.i2c.mem_write(0,self.address,register)
self.i2c.mem_write(0b10100000, self.address, self.MCP23017_IOCON_BANK0)
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)
self.write(0x33)
self.write(0x32)
self.write(0x28)
self.write(self.LCD_CLEARDISPLAY)
self.write(self.LCD_CURSORSHIFT | self.displayshift)
self.write(self.LCD_ENTRYMODESET | self.displaymode)
self.write(self.LCD_DISPLAYCONTROL | self.displaycontrol)
self.write(self.LCD_RETURNHOME)
flip = ( 0b00000000, 0b00010000, 0b00001000, 0b00011000,
0b00000100, 0b00010100, 0b00001100, 0b00011100,
0b00000010, 0b00010010, 0b00001010, 0b00011010,
0b00000110, 0b00010110, 0b00001110, 0b00011110 )
def out4(self, bitmask, value):
hi = bitmask | self.flip[value >> 4]
lo = bitmask | self.flip[value & 0x0F]
return [hi | 0b00100000, hi, lo | 0b00100000, lo]
pollables = ( LCD_CLEARDISPLAY, LCD_RETURNHOME )
def write(self, value, char_mode=False):
if self.ddrb & 0b00010000:
lo = (self.portb & 0b00000001) | 0b01000000
hi = lo | 0b00100000
self.i2c.mem_write(lo,self.address,self.MCP23017_GPIOB)
while True:
self.i2c.send(hi,self.address)
bits = self.i2c.recv(1,self.address)
self.i2c.mem_write(bytearray([lo,hi,lo]),self.address,self.MCP23017_GPIOB)
if (bits[0] & 0b00000010) == 0: break
self.portb = lo
self.ddrb &= 0b11101111
self.i2c.mem_write(self.ddrb,self.address,self.MCP23017_IODIRB)
bitmask = self.portb & 0b00000001
if char_mode: bitmask |= 0b10000000
if isinstance(value, str):
last = len(value) - 1
data = []
for i, v in enumerate(value):
data.extend(self.out4(bitmask, ord(v)))
if (len(data) >= 32) or (i == last):
self.i2c.mem_write(bytearray(data),self.address,self.MCP23017_GPIOB)
self.portb = data[-1]
data = []
elif isinstance(value, list):
last = len(value) - 1
data = []
for i, v in enumerate(value):
data.extend(self.out4(bitmask, v))
if (len(data) >= 32) or (i == last):
self.i2c.mem_write(data,self.address,self.MCP23017_GPIOB)
self.portb = data[-1]
data = []
else:
data = self.out4(bitmask, value)
self.i2c.mem_write(bytearray(data),self.address,self.MCP23017_GPIOB)
self.portb = data[-1]
if (not char_mode) and (value in self.pollables):
self.ddrb |= 0b00010000
self.i2c.mem_write(self.ddrb,self.address,self.MCP23017_IODIRB)
def begin(self, cols, lines):
self.currline = 0
self.numlines = lines
self.clear()
def clear(self):
self.write(self.LCD_CLEARDISPLAY)
def home(self):
self.write(self.LCD_RETURNHOME)
row_offsets = ( 0x00, 0x40, 0x14, 0x54 )
def setCursor(self, col, row):
if row > self.numlines: row = self.numlines - 1
elif row < 0: row = 0
self.write(self.LCD_SETDDRAMADDR | (col + self.row_offsets[row]))
def display(self):
self.displaycontrol |= self.LCD_DISPLAYON
self.write(self.LCD_DISPLAYCONTROL | self.displaycontrol)
def noDisplay(self):
self.displaycontrol &= ~self.LCD_DISPLAYON
self.write(self.LCD_DISPLAYCONTROL | self.displaycontrol)
def cursor(self):
self.displaycontrol |= self.LCD_CURSORON
self.write(self.LCD_DISPLAYCONTROL | self.displaycontrol)
def noCursor(self):
self.displaycontrol &= ~self.LCD_CURSORON
self.write(self.LCD_DISPLAYCONTROL | self.displaycontrol)
def ToggleCursor(self):
self.displaycontrol ^= self.LCD_CURSORON
self.write(self.LCD_DISPLAYCONTROL | self.displaycontrol)
def blink(self):
self.displaycontrol |= self.LCD_BLINKON
self.write(self.LCD_DISPLAYCONTROL | self.displaycontrol)
def noBlink(self):
self.displaycontrol &= ~self.LCD_BLINKON
self.write(self.LCD_DISPLAYCONTROL | self.displaycontrol)
def ToggleBlink(self):
self.displaycontrol ^= self.LCD_BLINKON
self.write(self.LCD_DISPLAYCONTROL | self.displaycontrol)
def scrollDisplayLeft(self):
self.displayshift = self.LCD_DISPLAYMOVE | self.LCD_MOVELEFT
self.write(self.LCD_CURSORSHIFT | self.displayshift)
def scrollDisplayRight(self):
self.displayshift = self.LCD_DISPLAYMOVE | self.LCD_MOVERIGHT
self.write(self.LCD_CURSORSHIFT | self.displayshift)
def leftToRight(self):
self.displaymode |= self.LCD_ENTRYLEFT
self.write(self.LCD_ENTRYMODESET | self.displaymode)
def rightToLeft(self):
self.displaymode &= ~self.LCD_ENTRYLEFT
self.write(self.LCD_ENTRYMODESET | self.displaymode)
def autoscroll(self):
self.displaymode |= self.LCD_ENTRYSHIFTINCREMENT
self.write(self.LCD_ENTRYMODESET | self.displaymode)
def noAutoscroll(self):
self.displaymode &= ~self.LCD_ENTRYSHIFTINCREMENT
self.write(self.LCD_ENTRYMODESET | self.displaymode)
def createChar(self, location, bitmap):
self.write(self.LCD_SETCGRAMADDR | ((location & 7) << 3))
self.write(bitmap, True)
self.write(self.LCD_SETDDRAMADDR)
def message(self, text):
lines = str(text).split('\n')
for i, line in enumerate(lines):
if i > 0:
self.write(0xC0)
self.write(line, True)
def backlight(self, color):
c = ~color
self.porta = (self.porta & 0b00111111) | ((c & 0b011) << 6)
self.portb = (self.portb & 0b11111110) | ((c & 0b100) >> 2)
self.i2c.mem_write(self.porta,self.address,self.MCP23017_GPIOA)
self.i2c.mem_write(self.portb,self.address,self.MCP23017_GPIOB)
def buttonPressed(self, b):
return (self.i2c.mem_read(1,self.address,self.MCP23017_GPIOA,timeout=100)[0] >> b) & 1
def buttons(self):
return self.i2c.mem_read(1,self.address,self.MCP23017_GPIOA,timeout=100)[0] & 0b11111