adafruit_tca8418

CircuitPython / Python library for TCA8418 Keyboard Multiplexor

  • Author(s): ladyada

Implementation Notes

Hardware:

Software and Dependencies:

# * Adafruit’s Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice # * Adafruit’s Register library: https://github.com/adafruit/Adafruit_CircuitPython_Register

class adafruit_tca8418.DigitalInOut(pin_number: int, tca: TCA8418)

Digital input/output of the TCA8418. The interface is exactly the same as the digitalio.DigitalInOut class, however:

  • TCA8418 does not support pull-down resistors

Exceptions will be thrown when attempting to set unsupported pull configurations.

  • Author(s): Tony DiCola

Parameters:

  • pin_number (int) – The pin number to use

  • tca (TCA8418) – The TCA8418 object associated with the DIO

Specify the pin number of the TCA8418 0..17, and instance.

property direction: Direction

The direction of the pin, works identically to the one in digitalio

property pull: Literal[digitalio.Pull.UP] | None

The pull setting for the digital IO, either digitalio.Pull.UP for pull up, or None for no pull up

switch_to_input(pull: Pull | None = None, **kwargs) → None

Switch the pin state to a digital input which is the same as setting the light pullup on. Note that true tri-state or pull-down resistors are NOT supported!

switch_to_output(value: bool = False, **kwargs) → None

Switch the pin state to a digital output with the provided starting value (True/False for high or low, default is False/low).

property value: bool

The value of the pin, either True for high/pulled-up or False for low.

class adafruit_tca8418.TCA8418(i2c_bus: I2C, address: int = 52)

Driver for the TCA8418 I2C Keyboard expander / multiplexor.

Parameters:

  • i2c_bus (I2C) – The I2C bus the TCA8418 is connected to.

  • address – The I2C device address. Defaults to 0x34

get_pin(pin: int) → DigitalInOut

Convenience function to create an instance of the DigitalInOut class pointing at the specified pin of this TCA8418 device.

Parameters:

pin (int) – Pin to use for digital IO, 0 to 17 inclusive; you can use the pins like TCA8418.R3 or TCA8418.C4 for convenience

property next_event: int

The next key event

class adafruit_tca8418.TCA8418_register(tca: TCA8418, base_addr: int, invert_value: bool = False, read_only: bool = False, initial_value: int | None = None)

A class for interacting with the TCA8418 registers

Parameters:

  • tca (TCA8418) – The associated TCA8418 object

  • base_addr (int) – The base address for this register

  • invert_value (bool) – Whether the value given should be interpreted as inverted (True -> False), default is False (inputs are as-is, not inverted)

  • read_only (bool) – Whether the register is read-only or read/write, default is False (register is read/write)

  • initial_value (int|None) – An initial value to provide to the register, default is None (no default is provided)