from microbit import *

# pin connections
rs = pin8
enable = pin2
datapins = [pin16, pin15, pin14, pin13]

# 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 entry mode
LCD_ENTRYRIGHT = 0x00
LCD_ENTRYLEFT = 0x02
LCD_ENTRYSHIFTINCREMENT = 0x01
LCD_ENTRYSHIFTDECREMENT = 0x00

# 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/ 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


def InitDisplay():
# at least 50ms after power on
sleep(50)
# send rs, enable low - rw is tied to GND
rs.write_digital(0)
enable.write_digital(0)
write4bits(0x03)
sleep(5)
write4bits(0x03)
sleep(5)
write4bits(0x03)
sleep(2)
write4bits(0x02)
send(LCD_FUNCTIONSET | 0x08, 0)
sleep(5)
send(LCD_FUNCTIONSET | 0x08, 0)
sleep(2)
send(LCD_FUNCTIONSET | 0x08, 0)
sleep(2)
send(LCD_FUNCTIONSET | 0x08, 0)
sleep(2)
send(LCD_DISPLAYCONTROL | LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF, 0)
clear()
send(LCD_ENTRYMODESET | LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT, 0)

# high level commands    
def clear():
send(LCD_CLEARDISPLAY, 0)
sleep(2)

def home():
send(LCD_RETURNHOME, 0)
sleep(2)

def setCursor(col, row):
orpart = col
if row> 0:
    orpart = orpart + 0x40
send(LCD_SETDDRAMADDR | orpart, 0)

def showText(t):
for c in t:
    send(ord(c), 1)

# mid and low level commands        
def send(value, mode):
rs.write_digital(mode)
write4bits(value >> 4)
write4bits(value)

def pulseEnable():
enable.write_digital(0)
sleep(1)
enable.write_digital(1)
sleep(1)
enable.write_digital(0)
sleep(1)

def write4bits(value):
for i in range(0, 4):
    datapins[i].write_digital((value >> i) & 0x01)
pulseEnable()

# Test
InitDisplay()
showText("Hello")
setCursor(0, 1)
showText("World")
sleep(5000)
clear()
showText("How are you?")