import time
from machine import Pin

rows = [Pin(2, Pin.OUT), Pin(1, Pin.OUT), Pin(0, Pin.OUT)]
cols = [Pin(28, Pin.OUT), Pin(27, Pin.OUT), Pin(26, Pin.OUT)]

def setup():
    for row in rows:
        row.value(0)
    for col in cols:
        col.value(1)

setup()

while True:
    for row in rows:
        row.value(1)
        for col in cols:
            col.value(0)
            time.sleep(0.5)
            col.value(1)
        row.value(0)