from machine import Pin
from utime import sleep

row=(Pin(15,Pin.OUT),Pin(14,Pin.OUT),Pin(13,Pin.OUT),
     Pin(12,Pin.OUT))
col=(Pin(11,Pin.IN,Pin.PULL_UP),Pin(10,Pin.IN,Pin.PULL_UP),
     Pin(9,Pin.IN,Pin.PULL_UP))

label="123456789*0#"

def getkey():
    val=0
    for j in range (4):
        for i in row:
            i.value(1)
        row[j].value(0)
        for i in range(3):
            if col[i].value()==0:
                val=label[i+j*3]
                sleep(0.1)
                while col[i].value()==0:
                    pass
         
    return val