from machine import Pin
from time import sleep

# Pin definitions for rows and columns of the keypad
rows = [Pin(2, Pin.OUT),
        Pin(3, Pin.OUT),
        Pin(4, Pin.OUT),
        Pin(5, Pin.OUT)]

cols = [Pin(6, Pin.IN, Pin.PULL_UP),
        Pin(7, Pin.IN, Pin.PULL_UP),
        Pin(8, Pin.IN, Pin.PULL_UP),
        Pin(9, Pin.IN, Pin.PULL_UP)]

# Keypad matrix (mapping rows and columns to keypad keys)
keypad = [
    ['1', '2', '3', 'A'],
    ['4', '5', '6', 'B'],
    ['7', '8', '9', 'C'],
    ['*', '0', '#', 'D']
]

while True:
    for row_num, row in enumerate(rows):
        row.value(0)  # Activate the current row
        for col_num, col in enumerate(cols):
            if col.value() == 0:  # Check if the key is pressed
                print("Key pressed: " + keypad[row_num][col_num])
                sleep(0.2)  # Debounce delay
        row.value(1)  # Deactivate the current row
    sleep(0.1)