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Cleaned up ESP32 DAC docs (#618) 

* Update esp32_dac.rst

* Clean up description and add use cases

* Format

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>
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Oskar Napieraj 2020-07-10 03:07:08 +02:00 committed by GitHub
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components/output/esp32_dac.rst
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@ -5,9 +5,14 @@ ESP32 DAC
:description: Instructions for setting up ESP32 digital-to-analog converter.
:image: dac.svg
The ESP32 DAC platform allows you to output arbitrary voltages using the 8-bit DAC on the ESP32. Two pins are supported: GPIO25 (Channel 1) and GPIO26 (Channel 2).
The ESP32 DAC platform allows you to output analog voltages using the 8-bit digital-to-analog
converter of the ESP32. Unlike the :doc:`/components/output/ledc`, which can simulate an analog
signal by using a fast switching frequency, the hardware DAC can output a *real* analog signal with
no need for additional filtering.
The output level is a percentage of VCC (3.3V).
The DAC spans across two pins, each on its own channel: GPIO25 (Channel 1) and GPIO26 (Channel 2).
The output level is a percentage of the board supply voltage (VDD_A) - generally this will be 3.3V.
.. code-block:: yaml
@ -29,10 +34,21 @@ The output level is a percentage of VCC (3.3V).
Configuration variables:
------------------------
- **pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): The pin to use DAC on. Only GPIO25 and GPIO26 are supported.
- **pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): The pin to use DAC on. Only GPIO25
and GPIO26 are supported.
- **id** (**Required**, :ref:`config-id`): The id to use for this output component.
- All other options from :ref:`Output <config-output>`.
Use Cases
---------
- Generating a specific (and dynamic) reference voltage for an external sensor or ADC, such as the
:doc:`/components/sensor/ads1115`
- Controlling the bias of a transistor
- Driving a bar graph or large amount of LEDs using an analog-controlled LED driver like the LM3914
(`datasheet <https://www.ti.com/lit/ds/symlink/lm3914.pdf>`__); this can allow you to make tank
level indicators, temperature gauges, and so on from a single output pin
See Also
--------