SN74HC165 I/O Expander (shift register)
=======================================

.. seo::
    :description: Instructions for setting up SN74HC165 shift registers as digital port expanders in ESPHome.

The SN74HC165 component allows you to use SN74HC165 shift registers as I/O expanders (Input only, use SN74HC595 for outputs)
(`datasheet <https://www.ti.com/lit/ds/symlink/sn74hc165.pdf>`__) in ESPHome. It uses 3 wires (optionally 4) for communication.

Once configured, you can use any of the 8 pins for your projects. Up-to 256 shift registers can be daisy-chained
to provide more pins, without using more GPIO pins on the controller. They are linked by connecting pin Q of the closer
shift register to the pin QH of the next shift register.


.. code-block:: yaml

    # Example configuration entry
    sn74hc165:
      - id: sn74hc165_hub
        clock_pin: GPIOXX
        data_pin: GPIOXX
        load_pin: GPIOXX
        clock_inhibit_pin: GPIOXX
        sr_count: 2

Configuration variables:
************************

- **id** (**Required**, :ref:`config-id`): The id to use for this SN74HC165 component.
- **data_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC165 Serial Output (QH) input.
- **clock_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC165 Clock (CLK) pin
- **load_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC165 Load input (SH/LD) pin
- **clock_inhibit_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC165 Clock Inhibit (CLK INH) pin
- **sr_count** (*Optional*, int): Number of daisy-chained shift registers, up-to 256. Defaults to ``1``.


Pin configuration variables:
****************************

.. code-block:: yaml

    # Individual inputs
    binary_sensor:
      - platform: gpio
        name: "SN74HC165 Pin #0"
        pin:
          sn74hc165: sn74hc165_hub
          # Use pin number 0
          number: 0
          inverted: false


- **sn74hc165** (**Required**, :ref:`config-id`): The id of the SN74HC165 component of the pin.
- **number** (**Required**, int): The pin number.
- **inverted** (*Optional*, boolean): If received value should be treated as inverted.
  Defaults to ``false``.

.. note::

    Pin number 0 is Pin A on the SN74HC165 that is furthest away from the microcontroller.

See Also
--------


- :doc:`binary_sensor/gpio`
- :apiref:`SN74HC165/SN74HC165.h`
- :ghedit:`Edit`