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140 lines
5.4 KiB
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140 lines
5.4 KiB
ReStructuredText
ESP32 LEDC Output
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=================
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.. seo::
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:description: Instructions for setting up LEDC hardware PWM outputs on the ESP32.
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:image: pwm.png
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The LEDC output component exposes a `LEDC PWM
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channel <https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/ledc.html>`__
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of the ESP32 as an output component.
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The frequency range of LEDC is from 10Hz to 40MHz - however, higher frequencies require a smaller
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bit depth which means the output is not that accurate for frequencies above ~300kHz.
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Example Usage For a Light
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*************************
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.. code-block:: yaml
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# Example configuration entry
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output:
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- platform: ledc
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pin: GPIO19
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id: gpio_19
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# Example usage in a light
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light:
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- platform: monochromatic
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output: gpio_19
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name: "Kitchen Light"
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Example Usage For a Piezo Buzzer
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********************************
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.. code-block:: yaml
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# Configure the output
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output:
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- platform: ledc
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######################################################
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# One buzzer leg connected to GPIO12, the other to GND
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######################################################
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pin: GPIO12
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id: buzzer
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# Example usage in an automation
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on_press:
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then:
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######################################################
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# Must be turned on before setting frequency & level
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######################################################
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- output.turn_on: buzzer
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######################################################
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# Frequency sets the wave size
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######################################################
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- output.ledc.set_frequency:
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id: buzzer
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frequency: "1000Hz"
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######################################################
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# level sets the %age time the PWM is on
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######################################################
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- output.set_level:
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id: buzzer
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level: "50%"
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Configuration variables:
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------------------------
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- **pin** (**Required**, :ref:`config-pin`): The pin to use LEDC on. Can only be GPIO0-GPIO33.
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- **id** (**Required**, :ref:`config-id`): The id to use for this output component.
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- **frequency** (*Optional*, float): At which frequency to run the LEDC
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channel’s timer. Defaults to 1000Hz.
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- All other options from :ref:`Output <config-output>`.
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Advanced options:
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- **channel** (*Optional*, int): Manually set the `LEDC
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channel <https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/ledc.html#configure-channel>`__
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to use. Two adjacent channels share the same timer. Defaults to an automatic selection.
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Recommended frequencies
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-----------------------
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To get the highest available frequency while still getting the same bit depth it is
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recommended to pick one of the following frequencies.
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Higher bit depth means that the light has more steps available to change from one
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value to another. This is especially noticeable when the light is below 10% and takes
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a long transition, e.g. turning slowly off.
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================================== =================================== ===================================
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**Frequency** **Bit depth** **Available steps for transitions**
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---------------------------------- ----------------------------------- -----------------------------------
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1220Hz 16 65536
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---------------------------------- ----------------------------------- -----------------------------------
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2441Hz 15 32768
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---------------------------------- ----------------------------------- -----------------------------------
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4882Hz 14 16384
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---------------------------------- ----------------------------------- -----------------------------------
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9765Hz 13 8192
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---------------------------------- ----------------------------------- -----------------------------------
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19531Hz 12 4096
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================================== =================================== ===================================
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The ESP8266 for instance has *usually* a frequency of 1000Hz with a resolution of 10 bits.
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This means that there are only 4 steps between each value.
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.. _output-ledc-set_frequency_action:
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``output.ledc.set_frequency`` Action
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------------------------------------
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This :ref:`Action <config-action>` allows you to manually change the frequency of an LEDC
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channel at runtime. Use cases include controlling a passive buzzer (for pitch control).
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.. code-block:: yaml
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on_...:
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- output.ledc.set_frequency:
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id: ledc_output
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frequency: 100Hz
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Configuration variables:
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- **id** (**Required**, :ref:`config-id`): The ID of the LEDC output to change.
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- **frequency** (**Required**, :ref:`templatable <config-templatable>`, float): The frequency
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to set in hertz.
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See Also
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--------
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- :doc:`/components/output/index`
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- :doc:`/components/output/esp8266_pwm`
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- :doc:`/components/light/monochromatic`
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- :doc:`/components/fan/speed`
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- :doc:`/components/power_supply`
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- :apiref:`ledc/ledc_output.h`
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- `esp-idf LEDC API docs <https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/ledc.html>`__
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- :ghedit:`Edit`
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