69 lines
1.9 KiB
ReStructuredText
69 lines
1.9 KiB
ReStructuredText
.. currentmodule:: machine
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.. _machine.DAC:
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class DAC -- digital to analog conversion
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=========================================
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The DAC is used to output an analog voltage based on a digital value.
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The output voltage will be between 0 and 3.3V.
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DAC is currently supported on ESP32 [#esp32_dac]_, SAMD and Renesas RA.
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.. note::
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The STM32 port has similar functionality to ``machine.DAC``. See
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:ref:`pyb.DAC <pyb.DAC>` for details.
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Example usage (ESP32)::
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from machine import DAC
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dac = DAC(pin) # create a DAC object acting on a pin
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dac.write(128) # write a value to the DAC
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dac.write(255) # output maximum value, 3.3V
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Constructors
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------------
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.. class:: DAC(id)
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Construct a new DAC object.
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``id`` is a pin object (ESP32 and Renesas RA) or an index to a DAC resource (SAMD).
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.. note::
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On the ESP32, DAC functionality is available on pins 25 and 26. On the
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ESP32-S2, pins 17 and 18. See :ref:`ESP32 Quickref <esp32_quickref>`
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for more details.
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.. note::
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SAMD21 has one DAC resource, SAMD51 has two. See :ref:`SAMD Quickref <samd_quickref>`
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for more details.
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Methods
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-------
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.. method:: DAC.write(value)
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Output an analog voltage to the pin connected to the DAC.
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``value`` is a representation of the desired output; a linear interpolation of
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0-3.3V, though the range differs depending on the port and micro, see below:
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+--------------+------+--------+
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| *Port/micro* | Bits | Range |
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+==============+======+========+
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| ESP32 | 8 | 0-255 |
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+--------------+------+--------+
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| SAMD21 | 10 | 0-1023 |
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+--------------+------+--------+
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| SAMD51 | 12 | 0-4095 |
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+--------------+------+--------+
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| Renesas RA | 12 | 0-4095 |
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+--------------+------+--------+
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.. rubric:: Footnotes
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.. [#esp32_dac] The original ESP32 and ESP32-S2 *only*, since DAC hardware is
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not present on other microcontrollers in the family.
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