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74 lines
2.0 KiB
74 lines
2.0 KiB
9 years ago
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.. _machine.ADC:
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class ADC -- analog to digital conversion
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=========================================
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Usage::
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import machine
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adc = machine.ADC() # create an ADC object
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apin = adc.channel(pin='GP3') # create an analog pin on GP3
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val = apin() # read an analog value
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Constructors
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------------
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.. class:: machine.ADC(id=0, \*, bits=12)
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Create an ADC object associated with the given pin.
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This allows you to then read analog values on that pin.
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For more info check the `pinout and alternate functions
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table. <https://raw.githubusercontent.com/wipy/wipy/master/docs/PinOUT.png>`_
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.. warning::
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ADC pin input range is 0-1.4V (being 1.8V the absolute maximum that it
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can withstand). When GP2, GP3, GP4 or GP5 are remapped to the
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ADC block, 1.8 V is the maximum. If these pins are used in digital mode,
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then the maximum allowed input is 3.6V.
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Methods
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-------
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.. method:: adc.channel(id, \*, pin)
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Create an analog pin. If only channel ID is given, the correct pin will
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be selected. Alternatively, only the pin can be passed and the correct
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channel will be selected. Examples::
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# all of these are equivalent and enable ADC channel 1 on GP3
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apin = adc.channel(1)
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apin = adc.channel(pin='GP3')
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apin = adc.channel(id=1, pin='GP3')
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.. method:: adc.init()
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Enable the ADC block.
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.. method:: adc.deinit()
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Disable the ADC block.
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class ADCChannel --- read analog values from internal or external sources
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=========================================================================
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ADC channels can be connected to internal points of the MCU or to GPIO pins.
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ADC channels are created using the ADC.channel method.
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.. method:: adcchannel()
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Fast method to read the channel value.
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.. method:: adcchannel.value()
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Read the channel value.
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.. method:: adcchannel.init()
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Re-init (and effectively enable) the ADC channel.
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.. method:: adcchannel.deinit()
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Disable the ADC channel.
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