esphome-docs/esphomeyaml/components/display/nextion.rst
2018-08-24 22:44:01 +02:00

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Nextion TFT LCD Display
=======================
The ``nextion`` display platform allows you to use Nextion LCD displays (`datasheet <https://nextion.itead.cc/resources/datasheets/>`__,
`iTead <https://www.itead.cc/display/nextion.html>`__)
with esphomelib.
.. figure:: images/nextion-full.jpg
:align: center
:width: 75.0%
Nextion LCD Display.
As the communication with the MH-Z19 is done using UART, you need to have an :ref:`UART bus <uart>`
in your configuration with ``rx_pin`` both the ``tx_pin`` set to the respective pins on the display.
Additionally, you need to set the baud rate to 9600.
.. code:: yaml
# Example configuration entry
uart:
rx_pin: D0
tx_pin: D1
baud_rate: 9600
display:
- platform: nextion
lambda: |-
it.set_component_value("gauge", 50);
it.set_component_text("textview", "Hello World!");
Configuration variables:
------------------------
- **uart_id** (*Optional*, :ref:`config-id`): The ID of the :ref:`UART bus <uart>` you wish to use for this display.
Use this if you want to use multiple UART buses at once.
- **lambda** (*Optional*, :ref:`lambda <config-lambda>`): The lambda to use for rendering the content on the nextion display.
See :ref:`display-nextion_lambda` for more information.
- **update_interval** (*Optional*, :ref:`config-time`): The interval to call the lambda to update the display.
Defaults to ``5s``.
- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.
.. _display-nextion_lambda:
Rendering Lambda
----------------
With Nextion displays, a dedicated chip on the display itself does the whole rendering. esphomelib can only
send *instructions* to the display to tell it *how* to render something and *what* to render.
First, you need to use the `Nextion Editor <https://nextion.itead.cc/resources/download/nextion-editor/>`__ to
create a display file and insert it using the SD card slot. Then, in the rendering ``lambda``, you have 3 main methods
you can call to populate data on the display:
.. code:: yaml
display:
- platform: nextion
# ...
lambda: |-
// set the "value" of a component - value is always an integer
// for example gauges represent their status using integers from 0 to 100
it.set_component_value("gauge", 50);
// set the text of a component
it.set_component_text("textview", "Hello World!");
// set the text of a component with formatting
it.set_component_text("textview", "The uptime is: %.1f", id(uptime_sensor).value);
Please see :ref:`display-printf` for a quick introduction into the ``printf`` formatting rules and
:ref:`display-strftime` for an introduction into the ``strftime`` time formatting. Additionally, check
out :ref:`api-display-nextion` for the full API of the Nextion display object.
See Also
--------
- :doc:`index`
- :doc:`API Reference </api/display/nextion>`
- `Simple Nextion Library <https://github.com/bborncr/nextion>`__ by `Bentley Born <https://github.com/bborncr>`__
- `Official Nextion Library <https://github.com/itead/ITEADLIB_Arduino_Nextion>`__ by `iTead <http://itead.cc/>`__
- `Edit this page on GitHub <https://github.com/OttoWinter/esphomedocs/blob/current/esphomeyaml/components/display/nextion.rst>`__