.. currentmodule:: machine .. _machine.DAC:

class DAC -- digital to analog conversion

The DAC is used to output an analog voltage based on a digital value.

The output voltage will be between 0 and 3.3V.

DAC is currently supported on ESP32 [#esp32_dac]_, SAMD and Renesas RA.

.. note:: The STM32 port has similar functionality to machine.DAC. See :ref:pyb.DAC <pyb.DAC> for details.

Example usage (ESP32)::

from machine import DAC

dac = DAC(pin)    # create a DAC object acting on a pin
dac.write(128)    # write a value to the DAC
dac.write(255)    # output maximum value, 3.3V

Constructors

.. class:: DAC(id)

Construct a new DAC object.

id is a pin object (ESP32 and Renesas RA) or an index to a DAC resource (SAMD).

.. note:: On the ESP32, DAC functionality is available on pins 25 and 26. On the ESP32-S2, pins 17 and 18. See :ref:ESP32 Quickref <esp32_quickref> for more details.

.. note:: SAMD21 has one DAC resource, SAMD51 has two. See :ref:SAMD Quickref <samd_quickref> for more details.

Methods

.. method:: DAC.write(value)

Output an analog voltage to the pin connected to the DAC.

value is a representation of the desired output; a linear interpolation of 0-3.3V, though the range differs depending on the port and micro, see below:

+--------------+------+--------+ | Port/micro | Bits | Range | +==============+======+========+ | ESP32 | 8 | 0-255 | +--------------+------+--------+ | SAMD21 | 10 | 0-1023 | +--------------+------+--------+ | SAMD51 | 12 | 0-4095 | +--------------+------+--------+ | Renesas RA | 12 | 0-4095 | +--------------+------+--------+

.. rubric:: Footnotes

.. [#esp32_dac] The original ESP32 and ESP32-S2 only, since DAC hardware is not present on other microcontrollers in the family.