Support I2C keypad

[petrkr]

Thinking how I can use input from external libraries like https://github.com/octopuslab-cz/micropython-keypad

maybe if it can handle some callbacks or I have to learn asyncio already to use Event() or something. Maybe we can somehow use/merge it...

I have that keypad in alpha state which "now just works", but I can rewrite it. I want to support interrupt than polling, but keep polling, because not always you have connected IRQ pin

[peterhinch]

I think the keypad driver would need to be modified to use uasyncio. Currently its read and input methods block, which would prevent display updates.

[petrkr]

Yes I know.. For this case I would use non-blocking get_key which can be ran in while True loop and if no key pressed, then it returns None.

read and input was designed to use with "spaghetti" code style for fast proof-of-concepts, also it call back "on_keypress" event, so I did tft refresh (or draw) in such callback.

I have to learn more about asyncio method of coding, but I still want to keep some "simple" blocking way so beginner programmer do not need handle callbacks etc, but for cost of blocking reads

[petrkr]

For now I wrapped my i2c keypad to emulated class and it works as proof-of-concept right.

class KeypadPin():
    def __init__(self, keypad, key, invert = False):
        self._kp = keypad
        self._inv = invert
        self._key = key

    def value(self, value = None):
        if value is not None:
            # we do not support set value here
            return

        return (1 if self._kp.get_key() == self._key else 0) ^ self._inv

    def __call__(self, value = None):
        return self.value(value)

Then I define it like this

BTN_INC = KeypadPin(keypad, '2', True)
BTN_DEC = KeypadPin(keypad, '8', True)
BTN_PRV = KeypadPin(keypad, '4', True)
BTN_NXT = KeypadPin(keypad, '6', True)
BTN_SEL = KeypadPin(keypad, '5', True)

[petrkr]

I think I am happy with this implementation, closing