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esp_adc: added adc filter doc, and filter migration guides

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Armando
2023-02-07 16:18:07 +08:00
committed by Armando (Dou Yiwen)
parent 3afa671069
commit 7e6bf9f987
5 changed files with 27 additions and 3 deletions
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24
docs/en/api-reference/peripherals/adc_continuous.rst
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@@ -71,6 +71,26 @@ After setting up above configurations for the ADC, call :cpp:func:`adc_continuou
If the ADC continuous mode driver is no longer used, you should deinitialize the driver by calling :cpp:func:`adc_continuous_deinit`.
.. only:: SOC_ADC_DIG_IIR_FILTER_SUPPORTED
Two IIR filters are available when ADC is working under continuous mode. To create an ADC IIR filter, you should set up the :cpp:type:`adc_continuous_iir_filter_config_t`, and call :cpp:func:`adc_new_continuous_iir_filter`.
- :cpp:member:`adc_digi_filter_config_t::unit`, ADC unit.
- :cpp:member:`adc_digi_filter_config_t::channel`, ADC channel to be filtered.
- :cpp:member:`adc_digi_filter_config_t::coeff`, filter coefficient.
.. only:: SOC_ADC_DIG_IIR_FILTER_UNIT_BINDED
On ESP32S2, the filter is per ADC unit. Once a filter is enabled, all the enabled ADC channels in this ADC unit will be filtered. However, we suggest only enabling one ADC channel per unit, when using the filter feature. Because the filtered results depend on the previous filtered result. So you should not enable multiple ADC channels, to avoid mixing the filtered results.
To recycle a filter, you should call :cpp:func:`adc_del_continuous_iir_filter`.
.. only:: not SOC_ADC_DIG_IIR_FILTER_UNIT_BINDED
.. note::
If you use both the filters on a same ADC channel, then only the first one will take effect.
Initialize the ADC Continuous Mode Driver
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -120,6 +140,10 @@ This API may fail due to reasons like :c:macro:`ESP_ERR_INVALID_ARG`. When it re
See ADC continuous mode example :example:`peripherals/adc/continuous_read` to see configuration codes.
.. only:: SOC_ADC_DIG_IIR_FILTER_SUPPORTED
To enable / disable the ADC IIR filter, you should call :cpp:func:`adc_continuous_iir_filter_enable` / :cpp:func:`adc_continuous_iir_filter_disable`.
ADC Control
^^^^^^^^^^^