from machine import Pin
import utime 
PORT = [3, 2, 1, 0]
DIR = ["0","0","0","0"]
L = [0]*4

def Configure_Port():
    for i in range(0, 4):
        if DIR[i] == "0":
            L[i] = Pin(PORT[i], Pin.OUT)
        else:
            L[i] = Pin(PORT[i], Pin.IN)
    return

def Port_Output(x):
    b = bin(x)
    b = b.replace("0b", "")
    diff = 4 - len(b)
    for i in range(0, diff):
        b = "0" + b 

    for i in range(0, 4):
        if b[i] == "1":
            L[i].value(1)
        else:
            L[i].value(0)
    return

Configure_Port()
cnt = 0

while True:
    Port_Output(cnt)
    utime.sleep(1)
    cnt = cnt + 1
    if cnt > 15:
        cnt = 0

'''
led1= Pin(0, Pin.OUT)
led2= Pin(1, Pin.OUT)
led3= Pin(2, Pin.OUT)
led4= Pin(3, Pin.OUT)
while True:


    led4.value(0)
    led3.value(0)
    led2.value(0)
    led1.value(0)
    sleep(1)

    led4.value(0)
    led3.value(0)
    led2.value(0)
    led1.value(1)
    sleep(1)

    led4.value(0)
    led3.value(0)
    led2.value(1)
    led1.value(0)
    sleep(1)

    led4.value(0)
    led3.value(0)
    led2.value(1)
    led1.value(1)
    sleep(1)

    led4.value(0)
    led3.value(1)
    led2.value(0)
    led1.value(0)
    sleep(1)

'''