esphome-docs/esphomeyaml/components/pcf8574.rst
2018-06-03 12:50:49 +02:00

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PCF8574 I/O Expander
====================
The PCF8574 component allows you to use PCF8574 or PCF8575 I/O expanders
(`datasheet <http://www.ti.com/lit/ds/symlink/pcf8574.pdf>`__,
`Sparkfun`_) in esphomeyaml. It
uses :ref:`I²C Bus <i2c>` for communication.
Once configured, you can use any of the 8 pins (PCF8574) or 16 pins (PCF8575) as
pins for your projects. Within esphomelib they emulate a real internal GPIO pin
and can therefore be used with many of esphomelib's components such as the GPIO
binary sensor or GPIO switch.
Any option accepting a :ref:`Pin Schema <config-pin_schema>` can theoretically be used, but some more
complicated components that do communication through this I/O expander will
not work.
.. figure:: images/pcf8574-full.jpg
:align: center
:target: `Sparkfun`_
:width: 50.0%
PCF8574 I/O Expander. Image by `Sparkfun`_.
.. _Sparkfun: https://www.sparkfun.com/products/retired/8130
.. code:: yaml
# Example configuration entry
pcf8574:
- id: 'pcf8574_hub'
address: 0x21
pcf8575: False
# Individual outputs
switch:
- platform: gpio
name: "PCF8574 Pin #0"
pin:
pcf8574: pcf8574_hub
# Use pin number 0
number: 0
# One of INPUT, INPUT_PULLUP or OUTPUT
mode: OUTPUT
inverted: False
Configuration variables:
~~~~~~~~~~~~~~~~~~~~~~~~
- **id** (**Required**, :ref:`config-id`): The id to use for this PCF8574 component.
- **address** (*Optional*, int): The I²C address of the driver.
Defaults to ``0x21``.
- **pcf8575** (*Optional*, boolean): Whether this is a 16-pin PCF8575. Defaults to ``False``.
See Also
--------
- :ref:`i2c`
- :doc:`switch/gpio`
- :doc:`binary_sensor/gpio`
- :doc:`API Reference </api/misc/pcf8574>`
- `Edit this page on GitHub <https://github.com/OttoWinter/esphomedocs/blob/master/esphomeyaml/components/pcf8574.rst>`__