from machine import Pin
import utime


matrix_keys=[['1','2','3','A']
             ['4','5','6','B']
             ['7','8','9','C']
             ['*','0','#','D']]


keypad_rows = [9,8,7,6]
keypad_columns = [5,4,3,2]


col_pins = []
row_pins = []
for x in range (0,4):
    row_pins.append(Pin(keypad_rows[x],Pin.OUT))
    row_pins[x].value(1)
    col_pins.append(Pin(keypad_columns[x],Pin.IN, Pin.PULL_DOWN))
    col_pins[x].value(0)


print ("Please enter a key from the keypad")
def scankeys():
    for row in range(4):
        for col in range(4):
            row_pins[row],high()
            key = None


            if col_pins[col].value() == 1:
               print("You have pressed:", matrix_keys[row][col])
               key_press = matrix_keys[row][col]
               utime.sleep(0.3)
            row_pins[row].low()
while True:
    scankeys()