esphome-docs/components/sn74hc595.rst
Davy Landman 7273822a94
Added alternative pin labeling for 74HC595 (#1930)
Some datasheets talk about the `SD`, `SH_CP` and `ST_CP` pins, I though to add the alternative label names in the documentation.
2022-03-10 21:03:38 -05:00

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SN74HC595 I/O Expander (shift register)
=======================================
.. seo::
:description: Instructions for setting up SN74HC595 shift registers as digital port expanders in ESPHome.
The SN74HC595 component allows you to use SN74HC595 shift registers as I/O expanders
(`datasheet <http://www.ti.com/lit/ds/symlink/sn74hc595.pdf>`__,
`SparkFun`_) 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 4 shift registers can be daisy-chained
to provide more pins, without using more GPIO pins on the controller.
Use of the OE pin is optional. If used, the pin should be pulled up externally.
.. figure:: images/sn74hc595-full.jpg
:align: center
:width: 80.0%
SN74HC595 I/O Expander (shift register).
.. _SparkFun: https://www.sparkfun.com/products/13699
.. code-block:: yaml
# Example configuration entry
sn74hc595:
- id: 'sn74hc595_hub'
data_pin: D5
clock_pin: D8
latch_pin: D7
oe_pin: D6
sr_count: 2
# Individual outputs
switch:
- platform: gpio
name: "SN74HC595 Pin #0"
pin:
sn74hc595: sn74hc595_hub
# Use pin number 0
number: 0
inverted: false
Configuration variables:
************************
- **id** (**Required**, :ref:`config-id`): The id to use for this SN74HC595 component.
- **data_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC595 SER (SD) input.
- **clock_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC595 SRCLK (SH_CP) pin
- **latch_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC595 RCLK (ST_CP) pin
- **oe_pin** (*Optional*, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC595 OE pin
- **sr_count** (*Optional*, int): Number of daisy-chained shift registers, up-to 4. Defaults to ``1``.
Pin configuration variables:
****************************
- **sn74hc595** (**Required**, :ref:`config-id`): The id of the SN74HC595 component of the pin.
- **number** (**Required**, int): The pin number.
- **inverted** (*Optional*, boolean): If all written values should be treated as inverted.
Defaults to ``false``.
See Also
--------
- :doc:`switch/gpio`
- :doc:`binary_sensor/gpio`
- `Serial to Parallel Shifting-Out with a 74HC595 <https://www.arduino.cc/en/tutorial/ShiftOut>`__
- :apiref:`sn74hc595/sn74hc595.h`
- :ghedit:`Edit`