67 lines
2.1 KiB
ReStructuredText
67 lines
2.1 KiB
ReStructuredText
.. currentmodule:: machine
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.. _machine.ADC:
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class ADC -- analog to digital conversion
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=========================================
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The ADC class provides an interface to analog-to-digital convertors, and
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represents a single endpoint that can sample a continuous voltage and
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convert it to a discretised value.
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For extra control over ADC sampling see :ref:`machine.ADCBlock <machine.ADCBlock>`.
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Example usage::
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from machine import ADC
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adc = ADC(pin) # create an ADC object acting on a pin
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val = adc.read_u16() # read a raw analog value in the range 0-65535
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val = adc.read_uv() # read an analog value in microvolts
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Constructors
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------------
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.. class:: ADC(id, *, sample_ns, atten)
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Access the ADC associated with a source identified by *id*. This
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*id* may be an integer (usually specifying a channel number), a
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:ref:`Pin <machine.Pin>` object, or other value supported by the
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underlying machine.
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If additional keyword-arguments are given then they will configure
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various aspects of the ADC. If not given, these settings will take
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previous or default values. The settings are:
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- *sample_ns* is the sampling time in nanoseconds.
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- *atten* specifies the input attenuation.
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Methods
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-------
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.. method:: ADC.init(*, sample_ns, atten)
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Apply the given settings to the ADC. Only those arguments that are
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specified will be changed. See the ADC constructor above for what the
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arguments are.
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.. method:: ADC.block()
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Return the :ref:`ADCBlock <machine.ADCBlock>` instance associated with
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this ADC object.
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This method only exists if the port supports the
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:ref:`ADCBlock <machine.ADCBlock>` class.
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.. method:: ADC.read_u16()
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Take an analog reading and return an integer in the range 0-65535.
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The return value represents the raw reading taken by the ADC, scaled
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such that the minimum value is 0 and the maximum value is 65535.
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.. method:: ADC.read_uv()
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Take an analog reading and return an integer value with units of
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microvolts. It is up to the particular port whether or not this value
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is calibrated, and how calibration is done.
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