import board
import keypad

keymatrix = keypad.KeyMatrix(
    row_pins = (board.GP5, board.GP6, board.GP7, board.GP8),
    column_pins = (board.GP9, board.GP10, board.GP11, board.GP12, board.GP13) )

keymap = {
    15:"0", 16:"1", 17:"2", 18:"3", 19:"runhalt",
    10:"4", 11:"5", 12:"6", 13:"7", 14:"step",
    5:"8", 6:"9", 7:"A", 8:"B", 9:"addr",
    0:"C", 1:"D", 2:"E", 3:"F", 4:"data" }

while True:
    keypad_event = keymatrix.events.get()
    keyPressed = True if (keypad_event and keypad_event.released ) else False
    key = keymap[keypad_event.key_number] if keyPressed else False
    if key:
        print(key)