62 lines
1.6 KiB
ReStructuredText
62 lines
1.6 KiB
ReStructuredText
Analog to Digital Converter
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===========================
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Overview
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--------
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ESP32 integrates two 12-bit SAR ("Successive Approximation Register") ADCs (Analog to Digital Converters) and supports measurements on 18 channels (analog enabled pins). Some of these pins can be used to build a programmable gain amplifier which is used for the measurement of small
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analog signals.
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The ADC driver API currently only supports ADC1 (9 channels, attached to GPIOs 32-39).
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Taking an ADC reading involves configuring the ADC with the desired precision and attentuation settings, and then calling adc1_get_voltage() to read the channel.
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It is also possible to read the internal hall effect sensor via ADC1.
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Application Example
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-------------------
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Reading voltage on ADC1 channel 0 (GPIO 36)::
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#include <driver/adc.h>
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...
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adc1_config_width(ADC_WIDTH_12Bit);
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adc1_config_channel_atten(ADC1_CHANNEL_0,ADC_ATTEN_0db);
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int val = adc1_get_voltage(ADC1_CHANNEL_0);
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Reading the internal hall effect sensor::
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#include <driver/adc.h>
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...
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adc1_config_width(ADC_WIDTH_12Bit);
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int val = hall_sensor_read();
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The value read in both these examples is 12 bits wide (range 0-4095).
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API Reference
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-------------
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Header Files
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^^^^^^^^^^^^
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* `components/driver/include/driver/adc.h`
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Enumerations
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^^^^^^^^^^^^
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.. doxygenenum:: adc1_channel_t
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.. doxygenenum:: adc_atten_t
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.. doxygenenum:: adc_bits_width_t
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Functions
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^^^^^^^^^
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.. doxygenfunction:: adc1_config_width
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.. doxygenfunction:: adc1_config_channel_atten
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.. doxygenfunction:: adc1_get_voltage
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.. doxygenfunction:: hall_sensor_read
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