kopia lustrzana https://github.com/espressif/esp-idf
42 wiersze
1.3 KiB
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42 wiersze
1.3 KiB
ReStructuredText
Digital To Analog Converter
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===========================
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Overview
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--------
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ESP32 has two 8-bit DAC (digital to analog converter) channels, connected to GPIO25 (Channel 1) and GPIO26 (Channel 2).
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The DAC driver allows these channels to be set to arbitrary voltages.
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The DAC channels can also be driven with DMA-style written sample data, via the :doc:`I2S driver <i2s>` when using the "built-in DAC mode".
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For other analog output options, see the :doc:`Sigma-delta Modulation module <sigmadelta>` and the :doc:`LED Control module <ledc>`. Both these modules produce high frequency PWM output, which can be hardware low-pass filtered in order to generate a lower frequency analog output.
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Application Example
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-------------------
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Setting DAC channel 1 (GPIO 25) voltage to approx 0.78 of VDD_A voltage (VDD * 200 / 255). For VDD_A 3.3V, this is 2.59V::
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#include <driver/dac.h>
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...
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dac_output_enable(DAC_CHANNEL_1);
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dac_output_voltage(DAC_CHANNEL_1, 200);
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API Reference
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-------------
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.. include:: /_build/inc/dac.inc
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GPIO Lookup Macros
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^^^^^^^^^^^^^^^^^^
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Some useful macros can be used to specified the GPIO number of a DAC channel, or vice versa.
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e.g.
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1. ``DAC_CHANNEL_1_GPIO_NUM`` is the GPIO number of channel 1 (25);
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2. ``DAC_GPIO26_CHANNEL`` is the channel number of GPIO 26 (channel 2).
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.. include:: /_build/inc/dac_channel.inc
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