dac.rst 1.7 KB

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  1. Digital To Analog Converter
  2. ===========================
  3. {IDF_TARGET_DAC_CH_1: default = "GPIO25", esp32 = "GPIO25", esp32s2 = "GPIO17"}
  4. {IDF_TARGET_DAC_CH_2: default = "GPIO26", esp32 = "GPIO26", esp32s2 = "GPIO18"}
  5. Overview
  6. --------
  7. {IDF_TARGET_NAME} has two 8-bit DAC (digital to analog converter) channels, connected to {IDF_TARGET_DAC_CH_1} (Channel 1) and {IDF_TARGET_DAC_CH_2} (Channel 2).
  8. The DAC driver allows these channels to be set to arbitrary voltages.
  9. 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".
  10. 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.
  11. Application Example
  12. -------------------
  13. Setting DAC channel 1 ({IDF_TARGET_DAC_CH_1}) voltage to approx 0.78 of VDD_A voltage (VDD * 200 / 255). For VDD_A 3.3V, this is 2.59V::
  14. #include <driver/dac.h>
  15. ...
  16. dac_output_enable(DAC_CHANNEL_1);
  17. dac_output_voltage(DAC_CHANNEL_1, 200);
  18. API Reference
  19. -------------
  20. .. include-build-file:: inc/dac.inc
  21. .. include-build-file:: inc/dac_common.inc
  22. GPIO Lookup Macros
  23. ^^^^^^^^^^^^^^^^^^
  24. Some useful macros can be used to specified the GPIO number of a DAC channel, or vice versa.
  25. e.g.
  26. 1. ``DAC_CHANNEL_1_GPIO_NUM`` is the GPIO number of channel 1 ({IDF_TARGET_DAC_CH_1});
  27. 2. ``DAC_{IDF_TARGET_DAC_CH_2}_CHANNEL`` is the channel number of GPIO 26 (channel 2).
  28. .. include-build-file:: inc/dac_channel.inc
  29. .. include-build-file:: inc/dac_types.inc