from keypad import*
from lcd4bit import*
lcd_start()
string_write("Question 3 (ii)")
sleep(5)
cmd_wrt(0x01)

while 1:
    
    val=keyread()
    
    if val=='A':
        cmd_wrt(0x01)#clear lcd
        cmd_wrt(0xc0+4) #secline=0xc0
        string_write("Welcome")
        sleep(0.5)

    elif val=='B':
        cmd_wrt(0x01)#clear lcd
        cmd_wrt(0xc0+4)
        string_write("Thank You")
        sleep(0.5)

    elif val=='C':
        cmd_wrt(0x01)#clear lcd
        cmd_wrt(0xc0+4)
        string_write("Please")
        sleep(0.5)

    elif val=='D':
        cmd_wrt(0x01)#clear lcd
        cmd_wrt(0xc0+4)
        string_write("Come Again")
        sleep(0.5)

    elif val=='#':
        cmd_wrt(0x01)#clear lcd
        cmd_wrt(0xc0+4)
        string_write("Later")
        sleep(0.5)

    elif val=='*':
        cmd_wrt(0x01) #clear lcd
        sleep(0.5)
    
    elif val!=0:
        cmd_wrt(0x80+7) #firstline=0x80
        string_write(val)
        sleep(0.2)



main.py

diagram.json

from machine import Pin
from time import sleep

dataline=[Pin(5,Pin.OUT),Pin(4,Pin.OUT),
          Pin(3,Pin.OUT),Pin(2,Pin.OUT)] #d4-d7

e=Pin(6,Pin.OUT)
rs=Pin(7,Pin.OUT)

def write(value):    
    dataline[0].value((value&0x10)>>4)
    dataline[1].value((value&0x20)>>5)
    dataline[2].value((value&0x40)>>6)
    dataline[3].value((value&0x80)>>7)    
    e.value(0)
    sleep(0.02)
    e.value(1)
    sleep(0.02)   
    dataline[0].value((value&0x01)>>0)
    dataline[1].value((value&0x02)>>1)
    dataline[2].value((value&0x04)>>2)
    dataline[3].value((value&0x08)>>3)    
    e.value(0)
    sleep(0.02)
    e.value(1)
    sleep(0.02)   

def cmd_wrt(value):  # write cmd
    rs.value(0)
    write(value)

def data_wrt(value): #cmd write
    rs.value(1)
    write(value)

def lcd_start():   
    cmd_wrt(0x02)
    sleep(0.1)
    cmd_wrt(0x28)
    sleep(0.1)
    cmd_wrt(0x0c)
    sleep(0.1)
    cmd_wrt(0x01)
    cmd_wrt(0x80)

def string_write(value):
    for i in value:
        data_wrt(ord(i))

def zfl(s,width):
    return '{:''>{w}}'.format(s,w=width)

def zfl_0(s,width):
    return '{:''0''>{w}}'.format(s,w=width)




   

lcd4bit.py

from machine import Pin
from time import sleep

row=[Pin(8, Pin.OUT),Pin(9, Pin.OUT),
     Pin(10, Pin.OUT),Pin(11, Pin.OUT)]

col=[Pin(12, Pin.IN, Pin.PULL_UP),Pin(13, Pin.IN, Pin.PULL_UP),
     Pin(14, Pin.IN, Pin.PULL_UP),Pin(15, Pin.IN, Pin.PULL_UP)]

label=['1','2','3','A',
       '4','5','6','B',
       '7','8','9','C',
       '*','0','#','D']

def keyread():
    for i in range(4): # bg nilai 1 for all row
          row[i].value(1) 
    for j in range(4):
          row[j].value(0)
          for i in range(4):
               val=col[i].value()
               while col[i].value()==0:
                    pass
               if val==0:
                    return label[i+4*j]
          row[j].value(1)
    return 0
    

