from machine import Pin

# 定义按键
NUM7, NUM8, NUM9, KEY_UP = range(4)
NUM4, NUM5, NUM6, KEY_DOWN = range(4, 8)
NUM1, NUM2, NUM3, KEY_OK = range(8, 12)
NUM0, KEY_L, KEY_R, KEY_CANCEL = range(12, 16)
NO_KEY = -1

# 定义键盘行和列的GPIO引脚
ROW_PINS = [
  Pin(33, Pin.OUT),
  Pin(34, Pin.OUT),
  Pin(35, Pin.OUT),
  Pin(36, Pin.OUT),
]

COLUMN_PINS = [
  Pin(38, Pin.IN),
  Pin(39, Pin.IN),
  Pin(40, Pin.IN),
  Pin(41, Pin.IN)
]


def init_keys():
  # 初始化键盘行
  for row in ROW_PINS:
    row.value(0)

  # 初始化键盘列
  for col in COLUMN_PINS:
    col.init(mode=Pin.IN)


def read_key():
  for r, row in enumerate(ROW_PINS):
    row.value(1)
    for c, col in enumerate(COLUMN_PINS):
      if col.value() == 1:
        row.value(0)
        return (4 * r) + c
    row.value(0)
  return NO_KEY


prev_key = NO_KEY
curr_key = NO_KEY


def read_key_on_released():
  global prev_key, curr_key
  curr_key = read_key()
  if prev_key != NO_KEY and curr_key == NO_KEY:
    p = prev_key
    prev_key = NO_KEY
    return p
  prev_key = curr_key
  return NO_KEY