131 lines
3.6 KiB
ReStructuredText
131 lines
3.6 KiB
ReStructuredText
I2S
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===
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Overview
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--------
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ESP32 contains two I2S peripherals. These peripherals can be configured to input and output sample data via the I2S driver.
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The I2S peripheral supports DMA meaning it can stream sample data without requiring each sample to be read or written by the CPU.
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I2S output can also be routed directly to the Digital/Analog Converter output channels (GPIO 25 & GPIO 26) to produce analog output directly, rather than via an external I2S codec.
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Application Example
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-------------------
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A full I2S example is available in esp-idf: :example:`peripherals/i2s`.
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Short example of I2S configuration::
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#include "driver/i2s.h"
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#include "freertos/queue.h"
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static const int i2s_num = 0; // i2s port number
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static const i2s_config_t i2s_config = {
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.mode = I2S_MODE_MASTER | I2S_MODE_TX,
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.sample_rate = 44100,
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.bits_per_sample = 16,
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.channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
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.communication_format = I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB,
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.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1, // high interrupt priority
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.dma_buf_count = 8,
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.dma_buf_len = 64
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};
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static const i2s_pin_config_t pin_config = {
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.bck_io_num = 26,
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.ws_io_num = 25,
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.data_out_num = 22,
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.data_in_num = I2S_PIN_NO_CHANGE
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};
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...
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i2s_driver_install(i2s_num, &i2s_config, 0, NULL); //install and start i2s driver
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i2s_set_pin(i2s_num, &pin_config);
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i2s_set_sample_rates(i2s_num, 22050); //set sample rates
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i2s_driver_uninstall(i2s_num); //stop & destroy i2s driver
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Short example configuring I2S to use internal DAC for analog output::
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#include "driver/i2s.h"
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#include "freertos/queue.h"
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static const int i2s_num = 0; // i2s port number
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static const i2s_config_t i2s_config = {
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.mode = I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_DAC_BUILT_IN,
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.sample_rate = 44100,
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.bits_per_sample = 8, /* must be 8 for built-in DAC */
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.channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
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.communication_format = I2S_COMM_FORMAT_I2S_MSB,
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.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1, // high interrupt priority
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.dma_buf_count = 8,
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.dma_buf_len = 64
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};
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...
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i2s_driver_install(i2s_num, &i2s_config, 0, NULL); //install and start i2s driver
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i2s_set_pin(i2s_num, NULL); //for internal DAC
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i2s_set_sample_rates(i2s_num, 22050); //set sample rates
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i2s_driver_uninstall(i2s_num); //stop & destroy i2s driver
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API Reference
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-------------
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Header Files
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^^^^^^^^^^^^
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* `components/driver/include/driver/i2s.h`
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Data Structures
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^^^^^^^^^^^^^^^
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.. doxygenstruct:: i2s_config_t
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:members:
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.. doxygenstruct:: i2s_event_t
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:members:
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.. doxygenstruct:: i2s_pin_config_t
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:members:
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Macros
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^^^^^^
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.. doxygendefine:: I2S_PIN_NO_CHANGE
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Enumerations
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^^^^^^^^^^^^
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.. doxygenenum:: i2s_bits_per_sample_t
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.. doxygenenum:: i2s_comm_format_t
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.. doxygenenum:: i2s_channel_fmt_t
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.. doxygenenum:: pdm_sample_rate_ratio_t
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.. doxygenenum:: pdm_pcm_conv_t
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.. doxygenenum:: i2s_port_t
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.. doxygenenum:: i2s_mode_t
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.. doxygenenum:: i2s_event_type_t
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Functions
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^^^^^^^^^
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.. doxygenfunction:: i2s_set_pin
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.. doxygenfunction:: i2s_driver_install
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.. doxygenfunction:: i2s_driver_uninstall
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.. doxygenfunction:: i2s_write_bytes
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.. doxygenfunction:: i2s_read_bytes
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.. doxygenfunction:: i2s_push_sample
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.. doxygenfunction:: i2s_pop_sample
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.. doxygenfunction:: i2s_set_sample_rates
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.. doxygenfunction:: i2s_start
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.. doxygenfunction:: i2s_stop
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.. doxygenfunction:: i2s_zero_dma_buffer
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