diff --git a/docs/en/api-reference/peripherals/i2s.rst b/docs/en/api-reference/peripherals/i2s.rst index 522f77b6fe8..4fd8d0c9b24 100644 --- a/docs/en/api-reference/peripherals/i2s.rst +++ b/docs/en/api-reference/peripherals/i2s.rst @@ -1,25 +1,26 @@ Inter-IC Sound (I2S) ==================== +:link_to_translation:`zh_CN:[中文]` {IDF_TARGET_I2S_NUM:default="one", esp32="two", esp32s3="two"} Introduction ------------ -I2S (Inter-IC Sound) is a serial, synchronous communication protocol that is usually used for transmitting audio data between two digital audio devices. +I2S (Inter-IC Sound) is a synchronous serial communication protocol usually used for transmitting audio data between two digital audio devices. {IDF_TARGET_NAME} contains {IDF_TARGET_I2S_NUM} I2S peripheral(s). These peripherals can be configured to input and output sample data via the I2S driver. -An I2S bus that communicate in Standard or TDM mode consists of the following lines: +An I2S bus that communicates in standard or TDM mode consists of the following lines: -- **MCLK:** Master clock line. It's an optional signal depends on slave side, mainly used for offering a reference clock to the I2S slave device. +- **MCLK:** Master clock line. It is an optional signal depending on the slave side, mainly used for offering a reference clock to the I2S slave device. - **BCLK:** Bit clock line. The bit clock for data line. -- **WS:** Word(Slot) select line. It is usually used to identify the vocal tract except PDM mode. -- **DIN/DOUT:** Serial data input/output line. (Data will loopback internally if din and dout are set to a same GPIO) +- **WS:** Word (Slot) select line. It is usually used to identify the vocal tract except PDM mode. +- **DIN/DOUT:** Serial data input/output line. Data will loopback internally if DIN and DOUT are set to a same GPIO. .. only:: SOC_I2S_SUPPORTS_PDM_TX or SOC_I2S_SUPPORTS_PDM_RX - And for the I2S bus that communicate in PDM mode, the lines are: + An I2S bus that communicates in PDM mode consists of the following lines: - **CLK:** PDM clock line. - **DIN/DOUT:** Serial data input/output line. @@ -28,15 +29,15 @@ Each I2S controller has the following features that can be configured by the I2S - Operation as system master or slave - Capable of acting as transmitter or receiver -- DMA controller that allows for streaming sample data without requiring the CPU to copy each data sample +- DMA controller that allows stream sampling of data without requiring the CPU to copy each data sample .. only:: SOC_I2S_HW_VERSION_1 - Each controller can operate in simplex communication mode. Thus, the two controllers can be combined to establish full-duplex communication. + Each controller supports single RX or TX simplex communication. As RX and TX channels share a clock, they can only be combined with the same configuration to establish a full-duplex communication. .. only:: SOC_I2S_HW_VERSION_2 - Each controller has separate rx and tx channel. That means they are able to work under different clock and slot configurations with separate GPIO pins. Note that although the internal MCLK of tx channel and rx channel are separate on a controller, the output MCLK signal can only be attached to one channel. If two different MCLK output is required, they must be allocated on different I2S controller. + Each controller has separate RX and TX channels. That means they are able to work under different clocks and slot configurations with separate GPIO pins. Note that although the internal MCLKs of TX channel and RX channel are separate on a controller, the output MCLK signal can only be attached to one channel. If independent MCLK output is required for each channel, they must be allocated on different I2S controllers. I2S File Structure ------------------ @@ -45,20 +46,22 @@ I2S File Structure :align: center :alt: I2S file structure -**Public headers that need to be included in the I2S application** + I2S File Structure -- ``i2s.h``: The header file of legacy I2S APIs (for apps using legacy driver). +**Public headers that need to be included in the I2S application are as follows:** + +- ``i2s.h``: The header file that provides legacy I2S APIs (for apps using legacy driver). - ``i2s_std.h``: The header file that provides standard communication mode specific APIs (for apps using new driver with standard mode). - ``i2s_pdm.h``: The header file that provides PDM communication mode specific APIs (for apps using new driver with PDM mode). - ``i2s_tdm.h``: The header file that provides TDM communication mode specific APIs (for apps using new driver with TDM mode). .. note:: - The legacy driver can't coexist with the new driver. Including ``i2s.h`` to use the legacy driver or the other three headers to use the new driver. The legacy driver might be removed in future. + The legacy driver cannot coexist with the new driver. Include ``i2s.h`` to use the legacy driver, or include the other three headers to use the new driver. The legacy driver might be removed in future. -**Public headers that have been included in the headers above** +**Public headers that have been included in the headers above are as follows:** -- ``i2s_types_legacy.h``: The legacy public types that only used in the legacy driver. +- ``i2s_types_legacy.h``: The header file that provides legacy public types that are only used in the legacy driver. - ``i2s_types.h``: The header file that provides public types. - ``i2s_common.h``: The header file that provides common APIs for all communication modes. @@ -80,20 +83,20 @@ Clock Source .. only:: SOC_I2S_SUPPORTS_APLL - - :cpp:enumerator:`i2s_clock_src_t::I2S_CLK_SRC_APLL`: Audio PLL clock, more precise than ``I2S_CLK_SRC_PLL_160M`` in high sample rate applications. Its frequency is configurable according to the sample rate, but if APLL has been occupied by emac or other channels already, the APLL frequency is not allowed to change, the driver will try to work under this APLL frequency, if this APLL frequency can't meet the requirements of I2S, the clock configuration will fail. + - :cpp:enumerator:`i2s_clock_src_t::I2S_CLK_SRC_APLL`: Audio PLL clock, which is more precise than ``I2S_CLK_SRC_PLL_160M`` in high sample rate applications. Its frequency is configurable according to the sample rate. However, if APLL has been occupied by EMAC or other channels, the APLL frequency cannot be changed, and the driver will try to work under this APLL frequency. If this frequency cannot meet the requirements of I2S, the clock configuration will fail. Clock Terminology ^^^^^^^^^^^^^^^^^ -- **sample rate**: The number of sampled data in one second per slot. -- **sclk**: Source clock frequency. It is the frequency of the clock source. -- **mclk**: Master clock frequency. ``bclk`` is generate from this clock, ``mclk`` is mostly needed in the case that requires the MCLK signal as a reference clock to synchronize BCLK and WS between I2S master role and slave role. -- **bclk**: Bit clock frequency. Every tick of this clock stands for one data bit on data pin. It means there will be 8/16/24/32 ``bclk`` ticks in one slot, because the number of ``bclk`` ticks in one slot is equal to the :cpp:member:`i2s_std_slot_config_t::slot_bit_width`. -- **lrck** / **ws**: Left/Right clock or word select clock. For non-PDM mode, its frequency is equal to the sample rate. +- **Sample rate**: The number of sampled data in one second per slot. +- **SCLK**: Source clock frequency. It is the frequency of the clock source. +- **MCLK**: Master clock frequency. BCLK is generated from this clock. The MCLK signal usually serves as a reference clock and is mostly needed to synchronize BCLK and WS between I2S master and slave roles. +- **BCLK**: Bit clock frequency. Every tick of this clock stands for one data bit on data pin. The slot bit width configured in :cpp:member:`i2s_std_slot_config_t::slot_bit_width` is equal to the number of BCLK ticks, which means there will be 8/16/24/32 BCLK ticks in one slot. +- **LRCK** / **WS**: Left/right clock or word select clock. For non-PDM mode, its frequency is equal to the sample rate. .. note:: - Normally ``mclk`` should be the multiple of ``sample rate`` and ``bclk`` at the same time. This field :cpp:member:`i2s_std_clk_config_t::mclk_multiple` means the multiple of ``mclk`` to the ``sample rate``. If ``slot_bit_width`` is set to ``I2S_SLOT_BIT_WIDTH_24BIT``, to keep ``mclk`` a multiple to the ``bclk``, :cpp:member:`i2s_std_clk_config_t::mclk_multiple` should be set to ``I2S_MCLK_MULTIPLE_384``, otherwise the ``ws`` will be inaccurate. But in the most other cases, ``I2S_MCLK_MULTIPLE_256`` should be enough. + Normally, MCLK should be the multiple of ``sample rate`` and BCLK at the same time. The field :cpp:member:`i2s_std_clk_config_t::mclk_multiple` indicates the multiple of MCLK to the ``sample rate``. In most cases, ``I2S_MCLK_MULTIPLE_256`` should be enough. However, if ``slot_bit_width`` is set to ``I2S_SLOT_BIT_WIDTH_24BIT``, to keep MCLK a multiple to the BCLK, :cpp:member:`i2s_std_clk_config_t::mclk_multiple` should be set to multiples that are divisible by 3 such as ``I2S_MCLK_MULTIPLE_384``. Otherwise, WS will be inaccurate. .. _i2s-communication-mode: @@ -107,26 +110,27 @@ Overview of All Modes Target Standard PDM TX PDM RX TDM ADC/DAC LCD/Camera ========= ======== ======== ======== ======== ======== ========== ESP32 I2S 0/1 I2S 0 I2S 0 none I2S 0 I2S 0 -ESP32S2 I2S 0 none none none none I2S 0 -ESP32C3 I2S 0 I2S 0 none I2S 0 none none -ESP32C6 I2S 0 I2S 0 none I2S 0 none none -ESP32S3 I2S 0/1 I2S 0 I2S 0 I2S 0/1 none none +ESP32-S2 I2S 0 none none none none I2S 0 +ESP32-C3 I2S 0 I2S 0 none I2S 0 none none +ESP32-C6 I2S 0 I2S 0 none I2S 0 none none +ESP32-S3 I2S 0/1 I2S 0 I2S 0 I2S 0/1 none none +ESP32-H2 I2S 0 I2S 0 none I2S 0 none none ========= ======== ======== ======== ======== ======== ========== Standard Mode ^^^^^^^^^^^^^ -Standard mode always has left and right two sound channels which are called 'slots'. These slots can support 8/16/24/32 bits width sample data. And the communication format for the slots mainly includes these following formats: +In standard mode, there are always two sound channels, i.e., the left and right channels, which are called "slots". These slots support 8/16/24/32-bit width sample data. The communication format for the slots mainly includes the followings: -- **Philips Format**: Data signal have one bit shift comparing to the WS(word select) signal. And the duty of WS signal is 50%. +- **Philips Format**: Data signal has one-bit shift comparing to the WS signal, and the duty of WS signal is 50%. .. wavedrom:: /../_static/diagrams/i2s/std_philips.json -- **MSB Format**: Almost same as philips format, but its data have no shift. +- **MSB Format**: Basically the same as Philips format, but without data shift. .. wavedrom:: /../_static/diagrams/i2s/std_msb.json -- **PCM Short Format**: Data have one bit shift and meanwhile WS signal becomes a pulse lasting one BCLK(Bit Clock) cycle. +- **PCM Short Format**: Data has one-bit shift and meanwhile the WS signal becomes a pulse lasting for one BCLK cycle. .. wavedrom:: /../_static/diagrams/i2s/std_pcm.json @@ -136,10 +140,10 @@ Standard mode always has left and right two sound channels which are called 'slo PDM Mode (TX) ^^^^^^^^^^^^^ - PDM(Pulse-density Modulation) mode for tx channel can convert PCM data into PDM format which always has left and right slots. PDM TX can only support 16 bits width sample data. PDM TX is only supported on I2S0, it needs at least a CLK pin for clock signal and a DOUT pin for data signal (i.e. WS and SD signal in the following figure, the BCK signal is an internal bit sampling clock, not needed between PDM devices). This mode allows user to configure the up-sampling parameters :cpp:member:`i2s_pdm_tx_clk_config_t::up_sample_fp` :cpp:member:`i2s_pdm_tx_clk_config_t::up_sample_fs`. The up-sampling rate can be calculated by ``up_sample_rate = fp / fs``, there are up-sampling modes in PDM TX: + PDM (Pulse-density Modulation) mode for the TX channel can convert PCM data into PDM format which always has left and right slots. PDM TX is only supported on I2S0 and it only supports 16-bit width sample data. It needs at least a CLK pin for clock signal and a DOUT pin for data signal (i.e., the WS and SD signal in the following figure; the BCK signal is an internal bit sampling clock, which is not needed between PDM devices). This mode allows users to configure the up-sampling parameters :cpp:member:`i2s_pdm_tx_clk_config_t::up_sample_fp`. The up-sampling rate can be calculated by ``up_sample_rate = fp / fs``. There are two up-sampling modes in PDM TX: - - **Fixed Clock Frequency**: In this mode the up-sampling rate will change according to the sample rate. Setting ``fp = 960`` and ``fs = sample_rate / 100``, then the clock frequency(Fpdm) on CLK pin will be fixed to 128 * 48 KHz = 6.144 MHz, note that this frequency is not equal to the sample rate(Fpcm). - - **Fixed Up-sampling Rate**: In this mode the up-sampling rate is fixed to 2. Setting ``fp = 960`` and ``fs = 480``, then the clock frequency(Fpdm) on CLK pin will be ``128 * sample_rate`` + - **Fixed Clock Frequency**: In this mode, the up-sampling rate changes according to the sample rate. Setting ``fp = 960`` and ``fs = sample_rate / 100``, then the clock frequency (Fpdm) on CLK pin will be fixed to ``128 * 48 KHz = 6.144 MHz``. Note that this frequency is not equal to the sample rate (Fpcm). + - **Fixed Up-sampling Rate**: In this mode, the up-sampling rate is fixed to 2. Setting ``fp = 960`` and ``fs = 480``, then the clock frequency (Fpdm) on CLK pin will be ``128 * sample_rate``. .. wavedrom:: /../_static/diagrams/i2s/pdm.json @@ -149,10 +153,10 @@ Standard mode always has left and right two sound channels which are called 'slo PDM Mode (RX) ^^^^^^^^^^^^^ - PDM(Pulse-density Modulation) mode for rx channel can receive PDM format data and convert the data into PCM format. PDM RX is only supported on I2S0, it can only support 16 bits width sample data. PDM RX needs at least a CLK pin for clock signal and a DIN pin for data signal. This mode allows user to configure the down-sampling parameter :cpp:member:`i2s_pdm_rx_clk_config_t::dn_sample_mode`, there are two down-sampling modes in PDM RX: + PDM (Pulse-density Modulation) mode for RX channel can receive PDM-format data and convert the data into PCM format. PDM RX is only supported on I2S0, and it only supports 16-bit width sample data. PDM RX needs at least a CLK pin for clock signal and a DIN pin for data signal. This mode allows users to configure the down-sampling parameter :cpp:member:`i2s_pdm_rx_clk_config_t::dn_sample_mode`. There are two down-sampling modes in PDM RX: - - :cpp:enumerator:`i2s_pdm_dsr_t::I2S_PDM_DSR_8S`: In this mode, the clock frequency(Fpdm) on WS pin will be sample_rate(Fpcm) * 64. - - :cpp:enumerator:`i2s_pdm_dsr_t::I2S_PDM_DSR_16S`: In this mode, the clock frequency(Fpdm) on WS pin will be sample_rate(Fpcm) * 128. + - :cpp:enumerator:`i2s_pdm_dsr_t::I2S_PDM_DSR_8S`: In this mode, the clock frequency (Fpdm) on the WS pin is ``sample_rate (Fpcm) * 64``. + - :cpp:enumerator:`i2s_pdm_dsr_t::I2S_PDM_DSR_16S`: In this mode, the clock frequency (Fpdm) on the WS pin is ``sample_rate (Fpcm) * 128``. .. only:: SOC_I2S_SUPPORTS_TDM @@ -160,29 +164,29 @@ Standard mode always has left and right two sound channels which are called 'slo TDM Mode ^^^^^^^^ - TDM(Time Division Multiplexing) mode supports up to 16 slots, these slots can be enabled by :cpp:member:`i2s_tdm_slot_config_t::slot_mask`. + TDM (Time Division Multiplexing) mode supports up to 16 slots. These slots can be enabled by :cpp:member:`i2s_tdm_slot_config_t::slot_mask`. .. only:: SOC_I2S_TDM_FULL_DATA_WIDTH - Any data bit-width is supported no matter how many slots are enabled, that means there can be up to ``32 bit-width * 16 slots = 512 bit`` in one frame. + Any data bit-width is supported no matter how many slots are enabled, which means there can be up to ``32 bit-width * 16 slots = 512 bit`` data in one frame. .. only:: not SOC_I2S_TDM_FULL_DATA_WIDTH - But due to the hardware limitation, only up to 4 slots are supported while the slot is set to 32 bit-width, and 8 slots for 16 bit-width, 16 slots for 8 bit-width. The slot communication format of TDM is almost same as standard mode, but there are some small differences between them. + But due to the hardware limitation, only up to 4 slots are supported while the slot is set to 32 bit-width, and 8 slots for 16 bit-width, 16 slots for 8 bit-width. The slot communication format of TDM is almost the same as the standard mode, yet with some small differences. - - **Philips Format**: Data signal have one bit shift comparing to the WS(word select) signal. And no matter how many slots are contained in one frame, the duty of WS signal will always keep 50%. + - **Philips Format**: Data signal has one-bit shift comparing to the WS signal. And no matter how many slots are contained in one frame, the duty of WS signal always keeps 50%. .. wavedrom:: /../_static/diagrams/i2s/tdm_philips.json - - **MSB Format**: Almost same as philips format, but its data have no shift. + - **MSB Format**: Basically the same as the Philips format, but without data shift. .. wavedrom:: /../_static/diagrams/i2s/tdm_msb.json - - **PCM Short Format**: Data have one bit shift and meanwhile WS signal becomes a pulse lasting one BCLK(Bit Clock) cycle for every frame. + - **PCM Short Format**: Data has one-bit shift and the WS signal becomes a pulse lasting one BCLK cycle for every frame. .. wavedrom:: /../_static/diagrams/i2s/tdm_pcm_short.json - - **PCM Long Format**: Data have one bit shift and meanwhile WS signal will lasting one slot bit width for every frame. For example, if there are 4 slots enabled, then the duty of WS will be 25%, and if there are 5 slots, it will be 20%. + - **PCM Long Format**: Data has one-bit shift and the WS signal lasts one-slot bit width for every frame. For example, the duty of WS will be 25% if there are four slots enabled, and 20% if there are five slots. .. wavedrom:: /../_static/diagrams/i2s/tdm_pcm_long.json @@ -191,96 +195,97 @@ Standard mode always has left and right two sound channels which are called 'slo LCD/Camera Mode ^^^^^^^^^^^^^^^ - LCD/Camera mode are only supported on I2S0 over a parallel bus. For LCD mode, I2S0 should working at master tx mode. For camera mode, I2S0 should working at slave rx mode. These two modes are not implemented by I2S driver, please refer to :doc:`/api-reference/peripherals/lcd` for LCD implementation. For more information, see *{IDF_TARGET_NAME} Technical Reference Manual* > *I2S Controller (I2S)* > LCD Mode [`PDF <{IDF_TARGET_TRM_EN_URL}#camlcdctrl>`__]. + LCD/Camera mode is only supported on I2S0 over a parallel bus. For LCD mode, I2S0 should work at master TX mode. For camera mode, I2S0 should work at slave RX mode. These two modes are not implemented by the I2S driver. Please refer to :doc:`/api-reference/peripherals/lcd` for details about the LCD implementation. For more information, see *{IDF_TARGET_NAME} Technical Reference Manual* > *I2S Controller (I2S)* > LCD Mode [`PDF <{IDF_TARGET_TRM_EN_URL}#camlcdctrl>`__]. .. only:: SOC_I2S_SUPPORTS_ADC_DAC ADC/DAC Mode ^^^^^^^^^^^^ - ADC and DAC modes only exist on ESP32 and are only supported on I2S0. Actually, they are two sub-modes of LCD/Camera mode. I2S0 can be routed directly to the internal analog-to-digital converter(ADC) and digital-to-analog converter(DAC). In other words, ADC and DAC peripherals can read or write continuously via I2S0 DMA. As they are not an actual communication mode, the I2S driver does not implement them. + ADC and DAC modes only exist on ESP32 and are only supported on I2S0. Actually, they are two sub-modes of LCD/Camera mode. I2S0 can be routed directly to the internal analog-to-digital converter (ADC) and digital-to-analog converter (DAC). In other words, ADC and DAC peripherals can read or write continuously via I2S0 DMA. As they are not actual communication modes, the I2S driver does not implement them. Functional Overview ------------------- -The I2S driver offers following services: +The I2S driver offers the following services: -Resources Management -^^^^^^^^^^^^^^^^^^^^ +Resource Management +^^^^^^^^^^^^^^^^^^^ -There are three levels' resources in I2S driver: +There are three levels of resources in the I2S driver: - ``platform level``: Resources of all I2S controllers in the current target. - ``controller level``: Resources in one I2S controller. -- ``channel level``: Resources of tx or rx channel in one I2S controller. +- ``channel level``: Resources of TX or RX channel in one I2S controller. -The public APIs are all channel level APIs, the channel handle :cpp:type:`i2s_chan_handle_t` can help user to manage the resources under a specific channel without considering the other two levels. The other two upper levels' resources are private and will be managed by the driver automatically. Users can call :cpp:func:`i2s_new_channel` to allocate a channel handle and call :cpp:func:`i2s_del_channel` to delete it. +The public APIs are all channel-level APIs. The channel handle :cpp:type:`i2s_chan_handle_t` can help users to manage the resources under a specific channel without considering the other two levels. The other two upper levels' resources are private and are managed by the driver automatically. Users can call :cpp:func:`i2s_new_channel` to allocate a channel handle and call :cpp:func:`i2s_del_channel` to delete it. Power Management ^^^^^^^^^^^^^^^^ -When the power management is enabled (i.e. :ref:`CONFIG_PM_ENABLE` is on), the system will adjust or stop the source clock of I2S before going into light sleep, thus potentially changing the I2S signals and leading to transmitting or receiving invalid data. +When the power management is enabled (i.e., :ref:`CONFIG_PM_ENABLE` is on), the system will adjust or stop the source clock of I2S before entering Light-sleep, thus potentially changing the I2S signals and leading to transmitting or receiving invalid data. -I2S driver can prevent the system from changing or stopping the source clock by acquiring a power management lock. When the source clock is generated from APB, the lock type will be set to :cpp:enumerator:`esp_pm_lock_type_t::ESP_PM_APB_FREQ_MAX` and when the source clock is APLL (if target support APLL), it will be set to :cpp:enumerator:`esp_pm_lock_type_t::ESP_PM_NO_LIGHT_SLEEP`. Whenever user is reading or writing via I2S (i.e. calling :cpp:func:`i2s_channel_read` or :cpp:func:`i2s_channel_write`), the driver will guarantee that the power management lock is acquired. Likewise, the driver releases the lock after reading or writing finished. +The I2S driver can prevent the system from changing or stopping the source clock by acquiring a power management lock. When the source clock is generated from APB, the lock type will be set to :cpp:enumerator:`esp_pm_lock_type_t::ESP_PM_APB_FREQ_MAX` and when the source clock is APLL (if supported), it will be set to :cpp:enumerator:`esp_pm_lock_type_t::ESP_PM_NO_LIGHT_SLEEP`. Whenever the user is reading or writing via I2S (i.e., calling :cpp:func:`i2s_channel_read` or :cpp:func:`i2s_channel_write`), the driver will guarantee that the power management lock is acquired. Likewise, the driver releases the lock after the reading or writing finishes. -Finite-State Machine +Finite State Machine ^^^^^^^^^^^^^^^^^^^^ -There are three states for an I2S channel, they are ``registered``, ``ready`` and ``running``. Their relationship is shown in the following diagram: +There are three states for an I2S channel, namely, ``registered``, ``ready``, and ``running``. Their relationship is shown in the following diagram: .. figure:: ../../../_static/diagrams/i2s/i2s_state_machine.png :align: center - :alt: I2S Finite-State Machine + :alt: I2S Finite State Machine + + I2S Finite State Machine -The ```` in the diagram can be replaced by corresponding I2S communication mode like ``std`` for standard two-slot mode, for other information of communication mode, please refer to :ref:`i2s-communication-mode` section. +The ```` in the diagram can be replaced by corresponding I2S communication modes, e.g., ``std`` for standard two-slot mode. For more information about communication modes, please refer to the :ref:`i2s-communication-mode` section. Data Transport ^^^^^^^^^^^^^^ -The data transport of I2S peripheral, including sending and receiving, is realized by DMA. Before transporting data, please call :cpp:func:`i2s_channel_enable` to enable the specific channel. When the sent or received data reach the size of one DMA buffer, ``I2S_OUT_EOF`` or ``I2S_IN_SUC_EOF`` interrupt will be triggered. Note that the DMA buffer size is not equal to :cpp:member:`i2s_chan_config_t::dma_frame_num`, one frame here means all the sampled data in one WS circle. Therefore, ``dma_buffer_size = dma_frame_num * slot_num * slot_bit_width / 8``. For the transmit case, users can input the data by calling :cpp:func:`i2s_channel_write`. This function will help users to copy the data from the source buffer to the DMA tx buffer and wait for the transmission finished. Then it'll repeat until the sent bytes reach the given size. For the receive case, the function :cpp:func:`i2s_channel_read` will wait for receiving the message queue which contains the DMA buffer address, it will help users to copy the data from DMA rx buffer to the destination buffer. +The data transport of the I2S peripheral, including sending and receiving, is realized by DMA. Before transporting data, please call :cpp:func:`i2s_channel_enable` to enable the specific channel. When the sent or received data reaches the size of one DMA buffer, the ``I2S_OUT_EOF`` or ``I2S_IN_SUC_EOF`` interrupt will be triggered. Note that the DMA buffer size is not equal to :cpp:member:`i2s_chan_config_t::dma_frame_num`. One frame here refers to all the sampled data in one WS circle. Therefore, ``dma_buffer_size = dma_frame_num * slot_num * slot_bit_width / 8``. For the data transmitting, users can input the data by calling :cpp:func:`i2s_channel_write`. This function helps users to copy the data from the source buffer to the DMA TX buffer and wait for the transmission to finish. Then it will repeat until the sent bytes reach the given size. For the data receiving, the function :cpp:func:`i2s_channel_read` waits to receive the message queue which contains the DMA buffer address. It helps users copy the data from the DMA RX buffer to the destination buffer. -Both :cpp:func:`i2s_channel_write` and :cpp:func:`i2s_channel_read` are blocking functions, they will keep waiting until the whole source buffer are sent or the whole destination buffer loaded, unless they exceed the max blocking time, then the error code `ESP_ERR_TIMEOUT` will return in this case. To send or receive data asynchronously, callbacks can be registered by :cpp:func:`i2s_channel_register_event_callback`, users are able to access the DMA buffer directly in the callback function instead of transmitting or receiving by the two blocking functions. However, please be aware that it is an interrupt callback, don't do complex logic, floating operation or call non-reentrant functions in the callback. +Both :cpp:func:`i2s_channel_write` and :cpp:func:`i2s_channel_read` are blocking functions. They keeps waiting until the whole source buffer is sent or the whole destination buffer is loaded, unless they exceed the max blocking time, where the error code `ESP_ERR_TIMEOUT` returns. To send or receive data asynchronously, callbacks can be registered by :cpp:func:`i2s_channel_register_event_callback`. Users are able to access the DMA buffer directly in the callback function instead of transmitting or receiving by the two blocking functions. However, please be aware that it is an interrupt callback, so do not add complex logic, run floating operation, or call non-reentrant functions in the callback. -Configuration Setting -^^^^^^^^^^^^^^^^^^^^^^ +Configuration +^^^^^^^^^^^^^ -Users can initialize a channel by corresponding function (i.e. :func:`i2s_channel_init_std_mode`, :func:`i2s_channel_init_pdm_rx_mode`, :func:`i2s_channel_init_pdm_tx_mode` or :func:`i2s_channel_init_tdm_mode`), the channel will be initialized to the specific mode. If the configurations need to be updated after initialization, :cpp:func:`i2s_channel_disable` has to be called first to ensure the channel has stopped, and then calling corresponding 'reconfig' functions, like :cpp:func:`i2s_channel_reconfig_std_slot`, :cpp:func:`i2s_channel_reconfig_std_clock`, :cpp:func:`i2s_channel_reconfig_std_gpio`. +Users can initialize a channel by calling corresponding functions (i.e., :func:`i2s_channel_init_std_mode`, :func:`i2s_channel_init_pdm_rx_mode`, :func:`i2s_channel_init_pdm_tx_mode`, or :func:`i2s_channel_init_tdm_mode`) to a specific mode. If the configurations need to be updated after initialization, users have to first call :cpp:func:`i2s_channel_disable` to ensure that the channel has stopped, and then call corresponding 'reconfig' functions, like :cpp:func:`i2s_channel_reconfig_std_slot`, :cpp:func:`i2s_channel_reconfig_std_clock`, and :cpp:func:`i2s_channel_reconfig_std_gpio`. IRAM Safe ^^^^^^^^^ -By default, the I2S interrupt will be deferred when the Cache is disabled for reasons like writing/erasing Flash. Thus the EOF interrupt will not get executed in time, which is not expected in a real-time application. +By default, the I2S interrupt will be deferred when the cache is disabled for reasons like writing/erasing flash. Thus the EOF interrupt will not get executed in time. -There's a Kconfig option :ref:`CONFIG_I2S_ISR_IRAM_SAFE` that will: +To avoid such case in real-time applications, you can enable the Kconfig option :ref:`CONFIG_I2S_ISR_IRAM_SAFE` that will: -1. Enable the interrupt being serviced even when cache is disabled +1. Keep the interrupt being serviced even when the cache is disabled. -2. Place driver object into DRAM (in case it's linked to PSRAM by accident) +2. Place driver object into DRAM (in case it is linked to PSRAM by accident). -This will allow the interrupt to run while the cache is disabled but will come at the cost of increased IRAM consumption. +This will allow the interrupt to run while the cache is disabled, but will come at the cost of increased IRAM consumption. Thread Safety ^^^^^^^^^^^^^ -All the public I2S APIs are guaranteed to be thread safe by the driver, which means, user can call them from different RTOS tasks without protection by extra locks. Notice that I2S driver uses mutex lock to ensure the thread safety, thus these APIs are not allowed to be used in ISR. +All the public I2S APIs are guaranteed to be thread safe by the driver, which means users can call them from different RTOS tasks without protection by extra locks. Notice that the I2S driver uses mutex lock to ensure the thread safety, thus these APIs are not allowed to be used in ISR. Kconfig Options ^^^^^^^^^^^^^^^ -- :ref:`CONFIG_I2S_ISR_IRAM_SAFE` controls whether the default ISR handler can work when cache is disabled, see `IRAM Safe <#iram-safe>`__ for more information. +- :ref:`CONFIG_I2S_ISR_IRAM_SAFE` controls whether the default ISR handler can work when the cache is disabled. See `IRAM Safe <#iram-safe>`__ for more information. - :ref:`CONFIG_I2S_SUPPRESS_DEPRECATE_WARN` controls whether to suppress the compiling warning message while using the legacy I2S driver. -- :ref:`CONFIG_I2S_ENABLE_DEBUG_LOG` is used to enabled the debug log output. Enable this option will increase the firmware binary size. +- :ref:`CONFIG_I2S_ENABLE_DEBUG_LOG` is used to enable the debug log output. Enable this option will increase the firmware binary size. Application Example ------------------- -The examples of the I2S driver can be found in the directory :example:`peripherals/i2s`. -Here are some simple usages of each mode: +The examples of the I2S driver can be found in the directory :example:`peripherals/i2s`. Here are some simple usages of each mode: Standard TX/RX Usage ^^^^^^^^^^^^^^^^^^^^ -Different slot communication formats can be generated by following helper macros for standard mode. As described above, there are three formats in standard mode, their helper macros are: +Different slot communication formats can be generated by the following helper macros for standard mode. As described above, there are three formats in standard mode, and their helper macros are: - :c:macro:`I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG` - :c:macro:`I2S_STD_PCM_SLOT_DEFAULT_CONFIG` @@ -290,13 +295,12 @@ The clock config helper macro is: - :c:macro:`I2S_STD_CLK_DEFAULT_CONFIG` -Please refer to :ref:`i2s-api-reference-i2s_std` for STD API information. -And for more details, please refer to :component_file:`driver/i2s/include/driver/i2s_std.h`. +Please refer to :ref:`i2s-api-reference-i2s_std` for information about STD API. And for more details, please refer to :component_file:`driver/i2s/include/driver/i2s_std.h`. STD TX Mode ~~~~~~~~~~~ -Take 16-bit data width for example, when the data in a ``uint16_t`` writting buffer are: +Take 16-bit data width for example. When the data in a ``uint16_t`` writing buffer are: +--------+--------+--------+--------+--------+--------+--------+--------+--------+ | data 0 | data 1 | data 2 | data 3 | data 4 | data 5 | data 6 | data 7 | ... | @@ -304,12 +308,12 @@ Take 16-bit data width for example, when the data in a ``uint16_t`` writting buf | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | ... | +--------+--------+--------+--------+--------+--------+--------+--------+--------+ -Here is the table of the real data on the line with different :cpp:member:`i2s_std_slot_config_t::slot_mode` and :cpp:member:`i2s_std_slot_config_t::slot_mask` +Here is the table of the real data on the line with different :cpp:member:`i2s_std_slot_config_t::slot_mode` and :cpp:member:`i2s_std_slot_config_t::slot_mask`. .. only:: esp32 +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ - | data bit width | slot mode | slot mask | ws low | ws high | ws low | ws high | ws low | ws high | ws low | ws high | + | data bit width | slot mode | slot mask | WS low | WS high | WS low | WS high | WS low | WS high | WS low | WS high | +================+===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ | | mono | left | 0x0002 | 0x0000 | 0x0001 | 0x0000 | 0x0004 | 0x0000 | 0x0003 | 0x0000 | | 16 bit | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ @@ -326,14 +330,14 @@ Here is the table of the real data on the line with different :cpp:member:`i2s_s .. note:: - It's similar when the data is 32-bit width, but take care when using 8-bit and 24-bit data width. For 8-bit width, the written buffer should still using ``uint16_t`` (i.e. align with 2 bytes), and only the high 8 bits will be valid, the low 8 bits are dropped, and for 24-bit width, the buffer is supposed to use ``uint32_t`` (i.e. align with 4 bytes), and only the high 24 bits valid, the low 8 bits are dropped. + It is similar when the data is 32-bit width, but take care when using 8-bit and 24-bit data width. For 8-bit width, the written buffer should still use ``uint16_t`` (i.e., align with 2 bytes), and only the high 8 bits are valid while the low 8 bits are dropped. For 24-bit width, the buffer is supposed to use ``uint32_t`` (i.e., align with 4 bytes), and only the high 24 bits are valid while the low 8 bits are dropped. - Another point is that, for the ``8-bit`` and ``16-bit`` mono mode, the real data on the line are swapped. To get the correct sequence, the writing buffer need to swap the data every two bytes. + Besides, for 8-bit and 16-bit mono modes, the real data on the line is swapped. To get the correct data sequence, the writing buffer needs to swap the data every two bytes. .. only:: esp32s2 +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ - | data bit width | slot mode | slot mask | ws low | ws high | ws low | ws high | ws low | ws high | ws low | ws high | + | data bit width | slot mode | slot mask | WS low | WS high | WS low | WS high | WS low | WS high | WS low | WS high | +================+===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ | | mono | left | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | 0x0000 | | 16 bit | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ @@ -350,12 +354,12 @@ Here is the table of the real data on the line with different :cpp:member:`i2s_s .. note:: - Similar for 8-bit and 32-bit data width, the type of the buffer is better to be ``uint8_t`` and ``uint32_t`` type. But specially, when the data width is 24-bit, the data buffer should aligned with 3-byte(i.e. every 3 bytes stands for a 24-bit data in one slot), additionally, :cpp:member:`i2s_chan_config_t::dma_frame_num`, :cpp:member:`i2s_std_clk_config_t::mclk_multiple` and the writing buffer size should be the multiple of ``3``, otherwise the data on the line or the sample rate will be incorrect. + Similar for 8-bit and 32-bit data widths, the type of the buffer is better to be ``uint8_t`` and ``uint32_t``. But specially, when the data width is 24-bit, the data buffer should be aligned with 3-byte (i.e., every 3 bytes stands for a 24-bit data in one slot). Additionally, :cpp:member:`i2s_chan_config_t::dma_frame_num`, :cpp:member:`i2s_std_clk_config_t::mclk_multiple`, and the writing buffer size should be the multiple of ``3``, otherwise the data on the line or the sample rate will be incorrect. .. only:: not (esp32 or esp32s2) +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ - | data bit width | slot mode | slot mask | ws low | ws high | ws low | ws high | ws low | ws high | ws low | ws high | + | data bit width | slot mode | slot mask | WS low | WS high | WS low | WS high | WS low | WS high | WS low | WS high | +================+===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ | | mono | left | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | 0x0000 | | 16 bit | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ @@ -372,7 +376,7 @@ Here is the table of the real data on the line with different :cpp:member:`i2s_s .. note:: - Similar for 8-bit and 32-bit data width, the type of the buffer is better to be ``uint8_t`` and ``uint32_t`` type. But specially, when the data width is 24-bit, the data buffer should aligned with 3-byte(i.e. every 3 bytes stands for a 24-bit data in one slot), additionally, :cpp:member:`i2s_chan_config_t::dma_frame_num`, :cpp:member:`i2s_std_clk_config_t::mclk_multiple` and the writing buffer size should be the multiple of ``3``, otherwise the data on the line or the sample rate will be incorrect. + Similar for 8-bit and 32-bit data widths, the type of the buffer is better to be ``uint8_t`` and ``uint32_t``. But specially, when the data width is 24-bit, the data buffer should be aligned with 3-byte (i.e., every 3 bytes stands for a 24-bit data in one slot). Additionally, :cpp:member:`i2s_chan_config_t::dma_frame_num`, :cpp:member:`i2s_std_clk_config_t::mclk_multiple`, and the writing buffer size should be the multiple of ``3``, otherwise the data on the line or the sample rate will be incorrect. .. code-block:: c @@ -380,15 +384,15 @@ Here is the table of the real data on the line with different :cpp:member:`i2s_s #include "driver/gpio.h" i2s_chan_handle_t tx_handle; - /* Get the default channel configuration by helper macro. - * This helper macro is defined in 'i2s_common.h' and shared by all the i2s communication mode. - * It can help to specify the I2S role, and port id */ + /* Get the default channel configuration by the helper macro. + * This helper macro is defined in 'i2s_common.h' and shared by all the I2S communication modes. + * It can help to specify the I2S role and port ID */ i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER); - /* Allocate a new tx channel and get the handle of this channel */ + /* Allocate a new TX channel and get the handle of this channel */ i2s_new_channel(&chan_cfg, &tx_handle, NULL); /* Setting the configurations, the slot configuration and clock configuration can be generated by the macros - * These two helper macros is defined in 'i2s_std.h' which can only be used in STD mode. + * These two helper macros are defined in 'i2s_std.h' which can only be used in STD mode. * They can help to specify the slot and clock configurations for initialization or updating */ i2s_std_config_t std_cfg = { .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(48000), @@ -409,7 +413,7 @@ Here is the table of the real data on the line with different :cpp:member:`i2s_s /* Initialize the channel */ i2s_channel_init_std_mode(tx_handle, &std_cfg); - /* Before write data, start the tx channel first */ + /* Before writing data, start the TX channel first */ i2s_channel_enable(tx_handle); i2s_channel_write(tx_handle, src_buf, bytes_to_write, bytes_written, ticks_to_wait); @@ -429,15 +433,15 @@ Here is the table of the real data on the line with different :cpp:member:`i2s_s STD RX Mode ~~~~~~~~~~~ -Take 16-bit data width for example, when the data on the line are: +Taking 16-bit data width for example, when the data on the line are: +--------+--------+--------+--------+--------+--------+--------+--------+--------+ -| ws low | ws high| ws low | ws high| ws low | ws high| ws low | ws high| ... | +| WS low | WS high| WS low | WS high| WS low | WS high| WS low | WS high| ... | +========+========+========+========+========+========+========+========+========+ | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | ... | +--------+--------+--------+--------+--------+--------+--------+--------+--------+ -Here is the table of the data that received in the buffer with different :cpp:member:`i2s_std_slot_config_t::slot_mode` and :cpp:member:`i2s_std_slot_config_t::slot_mask` +Here is the table of the data received in the buffer with different :cpp:member:`i2s_std_slot_config_t::slot_mode` and :cpp:member:`i2s_std_slot_config_t::slot_mask`. .. only:: esp32 @@ -453,9 +457,7 @@ Here is the table of the data that received in the buffer with different :cpp:me .. note:: - The receive case is a little bit complicated on ESP32. - Firstly, when the data width are ``8-bit`` or ``24-bit``, the received data will still align with two bytes or four bytes, which means the valid data are put in the high 8 bits in every two bytes and high 24 bits in every four bytes. For example, the received data will be ``0x5A00`` when the data on the line is ``0x5A`` in 8-bit width, and receive ``0x0000 5A00`` if the data ``0x00 005A`` on the line. - Secondly, for ``8-bit`` and ``16-bit`` mono case, the data in buffer are swapped every two data, they may need to be swapped back manually to get the correct order. + The receive case is a little bit complicated on ESP32. Firstly, when the data width is 8-bit or 24-bit, the received data will still align with two bytes or four bytes, which means that the valid data are put in the high 8 bits in every two bytes and high 24 bits in every four bytes. For example, the received data will be ``0x5A00`` when the data on the line is ``0x5A`` in 8-bit width, and ``0x0000 5A00`` if the data on the line is ``0x00 005A``. Secondly, for the 8-bit or 16-bit mono case, the data in buffer is swapped every two data, so it may be necessary to manually swap the data back to the correct order. .. only:: esp32s2 @@ -471,7 +473,7 @@ Here is the table of the data that received in the buffer with different :cpp:me .. note:: - ``8-bit``, ``24-bit`` and ``32-bit`` are similar as ``16-bit``, the data bit-width in the receiving buffer are equal to the data bit-width on the line. Additionally, when using ``24-bit`` data width, :cpp:member:`i2s_chan_config_t::dma_frame_num`, :cpp:member:`i2s_std_clk_config_t::mclk_multiple` and the receiving buffer size should be the multiple of ``3``, otherwise the data on the line or the sample rate will be incorrect. + 8-bit, 24-bit, and 32-bit are similar as 16-bit, where the data bit-width in the receiving buffer is equal to the data bit-width on the line. Additionally, when using 24-bit data width, :cpp:member:`i2s_chan_config_t::dma_frame_num`, :cpp:member:`i2s_std_clk_config_t::mclk_multiple`, and the receiving buffer size should be the multiple of ``3``, otherwise the data on the line or the sample rate will be incorrect. .. only:: not (esp32 or esp32s2) @@ -487,7 +489,7 @@ Here is the table of the data that received in the buffer with different :cpp:me .. note:: - ``8-bit``, ``24-bit`` and ``32-bit`` are similar as ``16-bit``, the data bit-width in the receiving buffer are equal to the data bit-width on the line. Additionally, when using ``24-bit`` data width, :cpp:member:`i2s_chan_config_t::dma_frame_num`, :cpp:member:`i2s_std_clk_config_t::mclk_multiple` and the receiving buffer size should be the multiple of ``3``, otherwise the data on the line or the sample rate will be incorrect. + 8-bit, 24-bit, and 32-bit are similar as 16-bit, the data bit-width in the receiving buffer is equal to the data bit-width on the line. Additionally, when using 24-bit data width, :cpp:member:`i2s_chan_config_t::dma_frame_num`, :cpp:member:`i2s_std_clk_config_t::mclk_multiple`, and the receiving buffer size should be the multiple of ``3``, otherwise the data on the line or the sample rate will be incorrect. .. code-block:: c @@ -496,14 +498,14 @@ Here is the table of the data that received in the buffer with different :cpp:me i2s_chan_handle_t rx_handle; /* Get the default channel configuration by helper macro. - * This helper macro is defined in 'i2s_common.h' and shared by all the i2s communication mode. - * It can help to specify the I2S role, and port id */ + * This helper macro is defined in 'i2s_common.h' and shared by all the I2S communication modes. + * It can help to specify the I2S role and port ID */ i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER); - /* Allocate a new rx channel and get the handle of this channel */ + /* Allocate a new RX channel and get the handle of this channel */ i2s_new_channel(&chan_cfg, NULL, &rx_handle); /* Setting the configurations, the slot configuration and clock configuration can be generated by the macros - * These two helper macros is defined in 'i2s_std.h' which can only be used in STD mode. + * These two helper macros are defined in 'i2s_std.h' which can only be used in STD mode. * They can help to specify the slot and clock configurations for initialization or updating */ i2s_std_config_t std_cfg = { .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(48000), @@ -524,7 +526,7 @@ Here is the table of the data that received in the buffer with different :cpp:me /* Initialize the channel */ i2s_channel_init_std_mode(rx_handle, &std_cfg); - /* Before read data, start the rx channel first */ + /* Before reading data, start the RX channel first */ i2s_channel_enable(rx_handle); i2s_channel_read(rx_handle, desc_buf, bytes_to_read, bytes_read, ticks_to_wait); @@ -536,10 +538,10 @@ Here is the table of the data that received in the buffer with different :cpp:me .. only:: SOC_I2S_SUPPORTS_PDM_TX - PDM TX usage + PDM TX Usage ^^^^^^^^^^^^ - For PDM mode in tx channel, the slot configuration helper macro is: + For PDM mode in TX channel, the slot configuration helper macro is: - :c:macro:`I2S_PDM_TX_SLOT_DEFAULT_CONFIG` @@ -547,10 +549,9 @@ Here is the table of the data that received in the buffer with different :cpp:me - :c:macro:`I2S_PDM_TX_CLK_DEFAULT_CONFIG` - Please refer to :ref:`i2s-api-reference-i2s_pdm` for PDM TX API information. - And for more details, please refer to :component_file:`driver/i2s/include/driver/i2s_pdm.h`. + Please refer to :ref:`i2s-api-reference-i2s_pdm` for information about PDM TX API. And for more details, please refer to :component_file:`driver/i2s/include/driver/i2s_pdm.h`. - The PDM data width is fixed to 16-bit, when the data in a ``int16_t`` writing buffer are: + The PDM data width is fixed to 16-bit. When the data in an ``int16_t`` writing buffer is: +--------+--------+--------+--------+--------+--------+--------+--------+--------+ | data 0 | data 1 | data 2 | data 3 | data 4 | data 5 | data 6 | data 7 | ... | @@ -586,15 +587,15 @@ Here is the table of the data that received in the buffer with different :cpp:me | line mode | slot mode | line | left | right | left | right | left | right | left | right | +================+===========+======+========+========+========+========+========+========+========+========+ | | mono | dout | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | 0x0000 | - | one-line codec +-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ + | one-line Codec +-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ | | stereo | dout | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | +----------------+-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ - | one-line dac | mono | dout | 0x0001 | 0x0001 | 0x0002 | 0x0002 | 0x0003 | 0x0003 | 0x0004 | 0x0004 | + | one-line DAC | mono | dout | 0x0001 | 0x0001 | 0x0002 | 0x0002 | 0x0003 | 0x0003 | 0x0004 | 0x0004 | +----------------+-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ | | mono | dout | 0x0002 | 0x0002 | 0x0004 | 0x0004 | 0x0006 | 0x0006 | 0x0008 | 0x0008 | | | +------+--------+--------+--------+--------+--------+--------+--------+--------+ | | | dout2| 0x0000 | 0x0000 | 0x0000 | 0x0000 | 0x0000 | 0x0000 | 0x0000 | 0x0000 | - | two-line dac +-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ + | two-line DAC +-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ | | stereo | dout | 0x0002 | 0x0002 | 0x0004 | 0x0004 | 0x0006 | 0x0006 | 0x0008 | 0x0008 | | | +------+--------+--------+--------+--------+--------+--------+--------+--------+ | | | dout2| 0x0001 | 0x0001 | 0x0003 | 0x0003 | 0x0005 | 0x0005 | 0x0007 | 0x0007 | @@ -602,7 +603,7 @@ Here is the table of the data that received in the buffer with different :cpp:me .. note:: - There are three line modes for PDM TX mode, they are ``I2S_PDM_TX_ONE_LINE_CODEC``, ``I2S_PDM_TX_ONE_LINE_DAC`` and ``I2S_PDM_TX_TWO_LINE_DAC``. One-line codec is for the PDM codecs those require clock signal, the PDM codec can differentiate the left and right slots by the clock level, and the other two are used to driver power amplifiers directly with a low-pass filter, they do not need the clock signal, so there are two lines to differentiate the left and right slots. Additionally, for the mono mode of one-line codec, the slot can be force to change to the right by setting the clock invert flag in gpio configuration. + There are three line modes for PDM TX mode, i.e., ``I2S_PDM_TX_ONE_LINE_CODEC``, ``I2S_PDM_TX_ONE_LINE_DAC``, and ``I2S_PDM_TX_TWO_LINE_DAC``. One-line codec is for the PDM codecs that require clock signal. The PDM codec can differentiate the left and right slots by the clock level. The other two modes are used to drive power amplifiers directly with a low-pass filter. They do not need the clock signal, so there are two lines to differentiate the left and right slots. Additionally, for the mono mode of one-line codec, users can force change the slot to the right by setting the clock invert flag in GPIO configuration. .. code-block:: c @@ -610,7 +611,7 @@ Here is the table of the data that received in the buffer with different :cpp:me #include "driver/i2s_pdm.h" #include "driver/gpio.h" - /* Allocate an I2S tx channel */ + /* Allocate an I2S TX channel */ i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_0, I2S_ROLE_MASTER); i2s_new_channel(&chan_cfg, &tx_handle, NULL); @@ -644,10 +645,9 @@ Here is the table of the data that received in the buffer with different :cpp:me - :c:macro:`I2S_PDM_RX_CLK_DEFAULT_CONFIG` - Please refer to :ref:`i2s-api-reference-i2s_pdm` for PDM RX API information. - And for more details, please refer to :component_file:`driver/i2s/include/driver/i2s_pdm.h`. + Please refer to :ref:`i2s-api-reference-i2s_pdm` for information about PDM RX API. And for more details, please refer to :component_file:`driver/i2s/include/driver/i2s_pdm.h`. - The PDM data width is fixed to 16-bit, when the data on the line (The PDM format on the line is transferred to PCM format for easier comprehension) are: + The PDM data width is fixed to 16-bit. When the data on the line (The PDM format on the line is transferred to PCM format for easier comprehension) is: +--------+--------+--------+--------+--------+--------+--------+--------+--------+ | left | right | left | right | left | right | left | right | ... | @@ -655,7 +655,7 @@ Here is the table of the data that received in the buffer with different :cpp:me | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | ... | +--------+--------+--------+--------+--------+--------+--------+--------+--------+ - Here is the table of the data that received in a 'int16_t' buffer with different :cpp:member:`i2s_pdm_rx_slot_config_t::slot_mode` and :cpp:member:`i2s_pdm_rx_slot_config_t::slot_mask` + Here is the table of the data received in a 'int16_t' buffer with different :cpp:member:`i2s_pdm_rx_slot_config_t::slot_mode` and :cpp:member:`i2s_pdm_rx_slot_config_t::slot_mask`. .. only:: esp32 @@ -683,9 +683,9 @@ Here is the table of the data that received in the buffer with different :cpp:me .. note:: - The right slot is received first in stereo mode. To switch the left and right slot in the buffer, please set the :cpp:member:`i2s_pdm_rx_gpio_config_t::invert_flags::clk_inv` to force invert the clock signal. + The right slot is received first in stereo mode. To switch the left and right slots in the buffer, please set the :cpp:member:`i2s_pdm_rx_gpio_config_t::invert_flags::clk_inv` to force invert the clock signal. - Specially, ESP32-S3 can support up to 4 data lines in PDM RX mode, each data line can be connected to two PDM MICs (left and right slots), which means the PDM RX on ESP32-S3 can support up to 8 PDM MICs. To enable multiple data lines, set the bits in :cpp:member:`i2s_pdm_rx_gpio_config_t::slot_mask` to enable corresponding slots first, and then set the data GPIOs in :cpp:type:`i2s_pdm_rx_gpio_config_t`. + Specially, ESP32-S3 supports up to 4 data lines in PDM RX mode, where each data line can be connected to two PDM MICs (left and right slots). This means that the PDM RX on ESP32-S3 can support up to 8 PDM MICs. To enable multiple data lines, set the bits in :cpp:member:`i2s_pdm_rx_gpio_config_t::slot_mask` to enable corresponding slots first, and then set the data GPIOs in :cpp:type:`i2s_pdm_rx_gpio_config_t`. .. code-block:: c @@ -694,7 +694,7 @@ Here is the table of the data that received in the buffer with different :cpp:me i2s_chan_handle_t rx_handle; - /* Allocate an I2S rx channel */ + /* Allocate an I2S RX channel */ i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_0, I2S_ROLE_MASTER); i2s_new_channel(&chan_cfg, NULL, &rx_handle); @@ -717,10 +717,10 @@ Here is the table of the data that received in the buffer with different :cpp:me .. only:: SOC_I2S_SUPPORTS_TDM - TDM TX/RX usage + TDM TX/RX Usage ^^^^^^^^^^^^^^^ - Different slot communication formats can be generated by following helper macros for TDM mode. As described above, there are four formats in TDM mode, their helper macros are: + Different slot communication formats can be generated by the following helper macros for TDM mode. As described above, there are four formats in TDM mode, and their helper macros are: - :c:macro:`I2S_TDM_PHILIPS_SLOT_DEFAULT_CONFIG` - :c:macro:`I2S_TDM_MSB_SLOT_DEFAULT_CONFIG` @@ -731,14 +731,13 @@ Here is the table of the data that received in the buffer with different :cpp:me - :c:macro:`I2S_TDM_CLK_DEFAULT_CONFIG` - Please refer to :ref:`i2s-api-reference-i2s_tdm` for TDM API information. - And for more details, please refer to :component_file:`driver/i2s/include/driver/i2s_tdm.h`. + Please refer to :ref:`i2s-api-reference-i2s_tdm` for information about TDM API. And for more details, please refer to :component_file:`driver/i2s/include/driver/i2s_tdm.h`. .. note:: - When setting the clock configuration for a slave role, please be aware that :cpp:member:`i2s_tdm_clk_config_t::bclk_div` should not be smaller than 8 (hardware limitation), increase this field can reduce the data lagging that sent from the slave. In the high sample rate case, the data might lag behind more than one ``bclk`` which will lead data malposition, you can try to increase :cpp:member:`i2s_tdm_clk_config_t::bclk_div` gradually to correct it. + Due to hardware limitation, when setting the clock configuration for a slave role, please be aware that :cpp:member:`i2s_tdm_clk_config_t::bclk_div` should not be smaller than 8. Increasing this field can reduce the lagging of the data sent from the slave. In the high sample rate case, the data might lag behind for more than one BCLK which will lead to data malposition. Users may gradually increase :cpp:member:`i2s_tdm_clk_config_t::bclk_div` to correct it. - As :cpp:member:`i2s_tdm_clk_config_t::bclk_div` is the division of ``mclk`` to ``bclk``, increase it will also increase the ``mclk`` frequency, therefore, the clock calculation might failed if the ``mclk`` is too high to divide from the source clock, which means :cpp:member:`i2s_tdm_clk_config_t::bclk_div` is not the bigger the better. + As :cpp:member:`i2s_tdm_clk_config_t::bclk_div` is the division of MCLK to BCLK, increasing it will also increase the MCLK frequency. Therefore, the clock calculation may fail if MCLK is too high to divide from the source clock. This means that a larger value for :cpp:member:`i2s_tdm_clk_config_t::bclk_div` is not necessarily better. TDM TX Mode ~~~~~~~~~~~ @@ -748,7 +747,7 @@ Here is the table of the data that received in the buffer with different :cpp:me #include "driver/i2s_tdm.h" #include "driver/gpio.h" - /* Allocate an I2S tx channel */ + /* Allocate an I2S TX channel */ i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER); i2s_new_channel(&chan_cfg, &tx_handle, NULL); @@ -810,9 +809,9 @@ Here is the table of the data that received in the buffer with different :cpp:me Full-duplex ^^^^^^^^^^^ -Full-duplex mode will register tx and rx channel in an I2S port at the same time, and they will share the BCLK and WS signal. Currently STD and TDM communication mode are able to adopt full-duplex mode in following way, but PDM full-duplex is not supported because PDM TX and RX clock are not same. +Full-duplex mode registers TX and RX channel in an I2S port at the same time, and the channels share the BCLK and WS signals. Currently, STD and TDM communication modes supports full-duplex mode in the following way, but PDM full-duplex is not supported because due to different PDM TX and RX clocks. -Note that one handle can only stand for one channel, the slot and clock configurations for both tx and rx channel should be set one by one. +Note that one handle can only stand for one channel. Therefore, it is still necessary to configure the slot and clock for both TX and RX channels one by one. Here is an example of how to allocate a pair of full-duplex channels: @@ -826,10 +825,10 @@ Here is an example of how to allocate a pair of full-duplex channels: /* Allocate a pair of I2S channel */ i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER); - /* Allocate for tx and rx channel at the same time, then they will work in full-duplex mode */ + /* Allocate for TX and RX channel at the same time, then they will work in full-duplex mode */ i2s_new_channel(&chan_cfg, &tx_handle, &rx_handle); - /* Set the configurations for BOTH TWO channels, since tx and rx channel have to be same in full-duplex mode */ + /* Set the configurations for BOTH TWO channels, since TX and RX channel have to be same in full-duplex mode */ i2s_std_config_t std_cfg = { .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(32000), .slot_cfg = I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO), @@ -859,7 +858,7 @@ Here is an example of how to allocate a pair of full-duplex channels: Simplex Mode ^^^^^^^^^^^^ - To allocate a channel handle in simplex mode, :cpp:func:`i2s_new_channel` should be called for each channel. The clock and gpio pins of TX/RX channel on {IDF_TARGET_NAME} are not separate, therefore TX and RX channel can't coexist on a same I2S port in simplex mode. + To allocate a channel handle in simplex mode, :cpp:func:`i2s_new_channel` should be called for each channel. The clock and GPIO pins of TX/RX channel on {IDF_TARGET_NAME} are not independent, so the TX and RX channel cannot coexist on the same I2S port in simplex mode. .. code-block:: c @@ -891,7 +890,7 @@ Here is an example of how to allocate a pair of full-duplex channels: i2s_channel_init_std_mode(tx_handle, &std_tx_cfg); i2s_channel_enable(tx_handle); - /* rx channel will be registered on another I2S, if no other available I2S unit found + /* RX channel will be registered on another I2S, if no other available I2S unit found * it will return ESP_ERR_NOT_FOUND */ i2s_new_channel(&chan_cfg, NULL, &rx_handle); i2s_std_config_t std_rx_cfg = { @@ -918,9 +917,9 @@ Here is an example of how to allocate a pair of full-duplex channels: Simplex Mode ^^^^^^^^^^^^ - To allocate a channel in simplex mode, :cpp:func:`i2s_new_channel` should be called for each channel. The clock and gpio pins of TX/RX channel on {IDF_TARGET_NAME} are separate, they can be configured in different modes and clocks, and they are able to coexist on a same I2S port in simplex mode. So PDM duplex can be realized by registering PDM TX simplex and PDM RX simplex on a same I2S port. But in this way, PDM TX/RX might work with different clocks, take care when configuring the gpio pins and clocks. + To allocate a channel in simplex mode, :cpp:func:`i2s_new_channel` should be called for each channel. The clock and GPIO pins of TX/RX channel on {IDF_TARGET_NAME} are independent, so they can be configured with different modes and clocks, and are able to coexist on the same I2S port in simplex mode. PDM duplex can be realized by registering PDM TX simplex and PDM RX simplex on the same I2S port. But in this way, PDM TX/RX might work with different clocks, so take care when configuring the GPIO pins and clocks. - The following example offers a use case for the simplex mode, but note that, although the internal MCLK signals for tx and rx channel are separate, the output MCLK can only be bound to one of them if they are from a same controller, if both channel initialized MCLK, it depends on which is initialized later. + The following example offers a use case for the simplex mode, but note that although the internal MCLK signals for TX and RX channel are separate, the output MCLK can only be bound to one of them if they are from the same controller. If MCLK has been initialized by both channels, it will be bound to the channel that initializes later. .. code-block:: c @@ -951,9 +950,9 @@ Here is an example of how to allocate a pair of full-duplex channels: i2s_channel_init_std_mode(tx_handle, &std_tx_cfg); i2s_channel_enable(tx_handle); - /* rx channel will be registered on another I2S, if no other available I2S unit found + /* RX channel will be registered on another I2S, if no other available I2S unit found * it will return ESP_ERR_NOT_FOUND */ - i2s_new_channel(&chan_cfg, NULL, &rx_handle); // Both rx and tx channel will be registered on I2S0, but they can work with different configurations. + i2s_new_channel(&chan_cfg, NULL, &rx_handle); // Both RX and TX channel will be registered on I2S0, but they can work with different configurations. i2s_std_config_t std_rx_cfg = { .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(16000), .slot_cfg = I2S_STD_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_32BIT, I2S_SLOT_MODE_STEREO), @@ -980,13 +979,13 @@ Application Notes How to Prevent Data Lost ^^^^^^^^^^^^^^^^^^^^^^^^ -For the applications that need a high frequency sample rate, sometimes the massive throughput of receiving data may cause data lost. Users can receive data lost event by registering isr callback function to receive event queue: +For applications that need a high frequency sample rate, the massive data throughput may cause data lost. Users can receive data lost event by registering the ISR callback function to receive the event queue: .. code-block:: c static IRAM_ATTR bool i2s_rx_queue_overflow_callback(i2s_chan_handle_t handle, i2s_event_data_t *event, void *user_ctx) { - // handle rx queue overflow event ... + // handle RX queue overflow event ... return false; } @@ -1000,16 +999,16 @@ For the applications that need a high frequency sample rate, sometimes the massi Please follow these steps to prevent data lost: -1. Determine the interrupt interval. Generally, when data lost happened, the interval should be the bigger the better, it can help to reduce the interrupt times, i.e., ``dma_frame_num`` should be as big as possible while the DMA buffer size won't exceed its maximum value 4092. The relationships are:: +1. Determine the interrupt interval. Generally, when data lost happens, the bigger the interval, the better, which helps to reduce the interrupt times. This means ``dma_frame_num`` should be as big as possible while the DMA buffer size is below the maximum value of 4092. The relationships are:: interrupt_interval(unit: sec) = dma_frame_num / sample_rate dma_buffer_size = dma_frame_num * slot_num * data_bit_width / 8 <= 4092 -2. Determine the ``dma_desc_num``. The ``dma_desc_num`` is decided by the max time of ``i2s_channel_read`` polling cycle, all the received data are supposed to be stored between two ``i2s_channel_read``. This cycle can be measured by a timer or an outputting gpio signal. The relationship is:: +2. Determine ``dma_desc_num``. ``dma_desc_num`` is decided by the maximum time of ``i2s_channel_read`` polling cycle. All the received data is supposed to be stored between two ``i2s_channel_read``. This cycle can be measured by a timer or an outputting GPIO signal. The relationship is:: dma_desc_num > polling_cycle / interrupt_interval -3. Determine the receiving buffer size. The receiving buffer that offered by user in ``i2s_channel_read`` should be able to take all the data in all dma buffers, that means it should be bigger than the total size of all the dma buffers:: +3. Determine the receiving buffer size. The receiving buffer offered by users in ``i2s_channel_read`` should be able to take all the data in all DMA buffers, which means that it should be larger than the total size of all the DMA buffers:: recv_buffer_size > dma_desc_num * dma_buffer_size @@ -1018,9 +1017,9 @@ For example, if there is an I2S application, and the known values are:: sample_rate = 144000 Hz data_bit_width = 32 bits slot_num = 2 - polling_cycle = 10ms + polling_cycle = 10 ms -Then the parameters ``dma_frame_num``, ``dma_desc_num`` and ``recv_buf_size`` can be calculated according to the given known values:: +Then the parameters ``dma_frame_num``, ``dma_desc_num``, and ``recv_buf_size`` can be calculated as follows:: dma_frame_num * slot_num * data_bit_width / 8 = dma_buffer_size <= 4092 dma_frame_num <= 511 diff --git a/docs/zh_CN/api-reference/peripherals/i2s.rst b/docs/zh_CN/api-reference/peripherals/i2s.rst index 493e5b949bb..f2182292eea 100644 --- a/docs/zh_CN/api-reference/peripherals/i2s.rst +++ b/docs/zh_CN/api-reference/peripherals/i2s.rst @@ -1 +1,1072 @@ -.. include:: ../../../en/api-reference/peripherals/i2s.rst \ No newline at end of file +I2S +=== +:link_to_translation:`en:[English]` + +{IDF_TARGET_I2S_NUM:default="1", esp32="2", esp32s3="2"} + +简介 +---- + +I2S（Inter-IC Sound，集成电路内置音频总线）是一种同步串行通信协议，通常用于在两个数字音频设备之间传输音频数据。 + +{IDF_TARGET_NAME} 包含 {IDF_TARGET_I2S_NUM} 个 I2S 外设。通过配置这些外设，可以借助 I2S 驱动来输入和输出采样数据。 + +标准或 TDM 通信模式下的 I2S 总线包含以下几条线路： + +- **MCLK**：主时钟线。该信号线可选，具体取决于从机，主要用于向 I2S 从机提供参考时钟。 +- **BCLK**：位时钟线。用于数据线的位时钟。 +- **WS**：字（声道）选择线。通常用于识别声道（除 PDM 模式外）。 +- **DIN/DOUT**：串行数据输入/输出线。如果 DIN 和 DOUT 被配置到相同的 GPIO，数据将在内部回环。 + +.. only:: SOC_I2S_SUPPORTS_PDM_TX or SOC_I2S_SUPPORTS_PDM_RX + + PDM 通信模式下的 I2S 总线包含以下几条线路： + + - **CLK**：PDM 时钟线。 + - **DIN/DOUT**：串行数据输入/输出线。 + +每个 I2S 控制器都具备以下功能，可由 I2S 驱动进行配置： + +- 可用作系统主机或从机 +- 可用作发射器或接收器 +- DMA 控制器支持流数据采样，CPU 无需单独复制每个采样数据 + +.. only:: SOC_I2S_HW_VERSION_1 + + 每个控制器都支持 RX 或 TX 单工通信。由于 RX 与 TX 通道共用一个时钟，因此只有在两者拥有相同配置时，才可以实现全双工通信。 + +.. only:: SOC_I2S_HW_VERSION_2 + + 每个控制器都有独立的 RX 和 TX 通道，连接到不同 GPIO 管脚，能够在不同的时钟和声道配置下工作。注意，尽管在一个控制器上 TX 通道和 RX 通道的内部 MCLK 相互独立，但输出的 MCLK 信号只能连接到一个通道。如果需要两个互相独立的 MCLK 输出，必须将其分配到不同的 I2S 控制器上。 + +I2S 文件结构 +------------ + +.. figure:: ../../../_static/diagrams/i2s/i2s_file_structure.png + :align: center + :alt: I2S 文件结构 + + I2S 文件结构 + +**需要包含在 I2S 应用中的公共头文件如下所示：** + +- ``i2s.h``：提供原有 I2S API（用于使用原有驱动的应用）。 +- ``i2s_std.h``：提供标准通信模式的 API（用于使用标准模式的新驱动程序的应用）。 +- ``i2s_pdm.h``：提供 PDM 通信模式的 API（用于使用 PDM 模式的新驱动程序的应用）。 +- ``i2s_tdm.h``：提供 TDM 通信模式的 API（用于使用 TDM 模式的新驱动的应用）。 + +.. note:: + + 原有驱动与新驱动无法共存。包含 ``i2s.h`` 以使用原有驱动，或包含其他三个头文件以使用新驱动。原有驱动未来可能会被删除。 + +**已包含在上述头文件中的公共头文件如下所示：** + +- ``i2s_types_legacy.h``：提供只在原有驱动中使用的原有公共类型。 +- ``i2s_types.h``：提供公共类型。 +- ``i2s_common.h``：提供所有通信模式通用的 API。 + +I2S 时钟 +-------- + +时钟源 +^^^^^^ + +- :cpp:enumerator:`i2s_clock_src_t::I2S_CLK_SRC_DEFAULT`：默认 PLL 时钟。 + +.. only:: not esp32h2 + + - :cpp:enumerator:`i2s_clock_src_t::I2S_CLK_SRC_PLL_160M`：160 MHz PLL 时钟。 + +.. only:: esp32h2 + + - :cpp:enumerator:`i2s_clock_src_t::I2S_CLK_SRC_PLL_96M`：96 MHz PLL 时钟。 + +.. only:: SOC_I2S_SUPPORTS_APLL + + - :cpp:enumerator:`i2s_clock_src_t::I2S_CLK_SRC_APLL`：音频 PLL 时钟，在高采样率应用中比 ``I2S_CLK_SRC_PLL_160M`` 更精确。其频率可根据采样率进行配置，但如果 APLL 已经被 EMAC 或其他通道占用，则无法更改 APLL 频率，驱动程序将尝试在原有 APLL 频率下工作。如果原有 APLL 频率无法满足 I2S 的需求，时钟配置将失败。 + +时钟术语 +^^^^^^^^ + +- **采样率**：单声道每秒采样数据数量。 +- **SCLK**：源时钟频率，即时钟源的频率。 +- **MCLK**：主时钟频率，BCLK 由其产生。MCLK 信号通常作为参考时钟，用于同步 I2S 主机和从机之间的 BCLK 和 WS。 +- **BCLK**：位时钟频率，一个 BCLK 时钟周期代表数据管脚上的一个数据位。通过 :cpp:member:`i2s_std_slot_config_t::slot_bit_width` 配置的通道位宽即为一个声道中的 BCLK 时钟周期数量，因此一个声道中可以有 8/16/24/32 个 BCLK 时钟周期。 +- **LRCK** / **WS**：左/右时钟或字选择时钟。在非 PDM 模式下，其频率等于采样率。 + +.. note:: + + 通常，MCLK 应该同时是 ``采样率`` 和 BCLK 的倍数。字段 :cpp:member:`i2s_std_clk_config_t::mclk_multiple` 表示 MCLK 相对于 ``采样率`` 的倍数。在大多数情况下，将其设置为 ``I2S_MCLK_MULTIPLE_256`` 即可。但如果 ``slot_bit_width`` 被设置为 ``I2S_SLOT_BIT_WIDTH_24BIT``，为了保证 MCLK 是 BCLK 的整数倍，应该将 :cpp:member:`i2s_std_clk_config_t::mclk_multiple` 设置为能被 3 整除的倍数，如 ``I2S_MCLK_MULTIPLE_384``，否则 WS 会不精准。 + +.. _i2s-communication-mode: + +I2S 通信模式 +------------ + +模式概览 +^^^^^^^^ + +========= ======== ======== ======== ======== ======== ========== +芯片 I2S 标准 PDM TX PDM RX TDM ADC/DAC LCD/摄像头 +========= ======== ======== ======== ======== ======== ========== +ESP32 I2S 0/1 I2S 0 I2S 0 无 I2S 0 I2S 0 +ESP32-S2 I2S 0 无 无 无 无 I2S 0 +ESP32-C3 I2S 0 I2S 0 无 I2S 0 无 无 +ESP32-C6 I2S 0 I2S 0 无 I2S 0 无 无 +ESP32-S3 I2S 0/1 I2S 0 I2S 0 I2S 0/1 无 无 +ESP32-H2 I2S 0 I2S 0 无 I2S 0 无 无 +========= ======== ======== ======== ======== ======== ========== + +标准模式 +^^^^^^^^ + +标准模式中有且仅有左右两个声道，驱动中将声道称为 slot。这些声道可以支持 8/16/24/32 位宽的采样数据，声道的通信格式主要包括以下几种： + +- **Philips 格式**：数据信号与 WS 信号相比有一个位的位移。WS 信号的占空比为 50%。 + +.. wavedrom:: /../_static/diagrams/i2s/std_philips.json + +- **MSB 格式**：与 Philips 格式基本相同，但其数据没有位移。 + +.. wavedrom:: /../_static/diagrams/i2s/std_msb.json + +- **PCM 帧同步**：数据有一个位的位移，同时 WS 信号变成脉冲，持续一个 BCLK 周期。 + +.. wavedrom:: /../_static/diagrams/i2s/std_pcm.json + + +.. only:: SOC_I2S_SUPPORTS_PDM_TX + + PDM 模式 (TX) + ^^^^^^^^^^^^^ + + 在 PDM（Pulse-density Modulation，脉冲密度调制）模式下，TX 通道可以将 PCM 数据转换为 PDM 格式，该格式始终有左右两个声道。PDM TX 只在 I2S0 中受支持，且只支持 16 位宽的采样数据。PDM TX 至少需要一个 CLK 管脚用于时钟信号，一个 DOUT 管脚用于数据信号（即下图中的 WS 和 SD 信号。BCK 信号为内部位采样时钟，在 PDM 设备之间不需要）。PDM 模式允许用户配置上采样参数 :cpp:member:`i2s_pdm_tx_clk_config_t::up_sample_fp`。上采样率可以通过公式 ``up_sample_rate = fp / fs`` 来计算，在 PDM TX 中有以下两种上采样模式： + + - **固定时钟频率模式**：在这种模式下，上采样率将根据采样率的变化而变化。设置 ``fp = 960``、 ``fs = sample_rate / 100``，则 CLK 管脚上的时钟频率 (Fpdm) 将固定为 ``128 * 48 KHz = 6.144 MHz``。注意此频率不等于采样率 (Fpcm)。 + - **固定上采样率模式**：在这种模式下，上采样率固定为 2。设置 ``fp = 960``、 ``fs = 480``，则 CLK 管脚上的时钟频率 (Fpdm) 将为 ``128 * sample_rate``。 + + .. wavedrom:: /../_static/diagrams/i2s/pdm.json + + +.. only:: SOC_I2S_SUPPORTS_PDM_RX + + PDM 模式 (RX) + ^^^^^^^^^^^^^ + + 在 PDM（Pulse-density Modulation，脉冲密度调制）模式下，RX 通道可以接收 PDM 格式的数据并将数据转换成 PCM 格式。PDM RX 只在 I2S0 中受支持，且只支持 16 位宽的采样数据。PDM RX 至少需要一个 CLK 管脚用于时钟信号，一个 DIN 管脚用于数据信号。此模式允许用户配置下采样参数 :cpp:member:`i2s_pdm_rx_clk_config_t::dn_sample_mode`。在 PDM RX 中有以下两种下采样模式： + + - :cpp:enumerator:`i2s_pdm_dsr_t::I2S_PDM_DSR_8S`：在这种模式下，WS 管脚的时钟频率 (Fpdm) 将为 ``sample_rate (Fpcm) * 64``。 + - :cpp:enumerator:`i2s_pdm_dsr_t::I2S_PDM_DSR_16S`： 在这种模式下，WS 管脚的时钟频率 (Fpdm) 将为 ``sample_rate (Fpcm) * 128``。 + + +.. only:: SOC_I2S_SUPPORTS_TDM + + TDM 模式 + ^^^^^^^^ + + TDM（Time Division Multiplexing，时分多路复用）模式最多支持 16 个声道，可通过 :cpp:member:`i2s_tdm_slot_config_t::slot_mask` 启用通道。 + + .. only:: SOC_I2S_TDM_FULL_DATA_WIDTH + + 该模式下无论启用多少声道，都支持任意数据位宽，也即一个帧中最多可以有 ``32 位宽 * 16 个声道 = 512 位`` 的数据。 + + .. only:: not SOC_I2S_TDM_FULL_DATA_WIDTH + + 但由于硬件限制，声道设置为 32 位宽时最多只能支持 4 个声道，16 位宽时最多只能支持 8 个声道，8 位宽时最多只能支持 16 个声道。TDM 的声道通信格式与标准模式基本相同，但有一些细微差别。 + + - **Philips 格式**：数据信号与 WS 信号相比有一个位的位移。无论一帧中包含多少个声道，WS 信号的占空比将始终保持为 50%。 + + .. wavedrom:: /../_static/diagrams/i2s/tdm_philips.json + + - **MSB 格式**：与 Philips 格式基本相同，但数据没有位移。 + + .. wavedrom:: /../_static/diagrams/i2s/tdm_msb.json + + - **PCM 短帧同步**：数据有一个位的位移，同时 WS 信号变为脉冲，每帧持续一个 BCLK 周期。 + + .. wavedrom:: /../_static/diagrams/i2s/tdm_pcm_short.json + + - **PCM 长帧同步**：数据有一个位的位移，同时 WS 信号将在每一帧持续一个声道的宽度。例如，如果启用了四个声道，那么 WS 的占空比将是 25%，如果启用了五个声道，则为 20%。 + + .. wavedrom:: /../_static/diagrams/i2s/tdm_pcm_long.json + +.. only:: SOC_I2S_SUPPORTS_LCD_CAMERA + + LCD/摄像头模式 + ^^^^^^^^^^^^^^^ + + LCD/摄像头模式只支持在 I2S0 上通过并行总线运行。在 LCD 模式下，I2S0 应当设置为主机 TX 模式；在摄像头模式下，I2S0 应当设置为从机 RX 模式。这两种模式不是由 I2S 驱动实现的，关于 LCD 模式的实现，请参阅 :doc:`/api-reference/peripherals/lcd`。更多信息请参考 *{IDF_TARGET_NAME} 技术参考手册* > *I2S 控制器 (I2S)* > LCD 模式 [`PDF <{IDF_TARGET_TRM_EN_URL}#camlcdctrl>`__]。 + +.. only:: SOC_I2S_SUPPORTS_ADC_DAC + + ADC/DAC 模式 + ^^^^^^^^^^^^^ + + 仅 ESP32 支持在 I2S0 上运行 ADC 和 DAC 模式。实际上，ADC 和 DAC 模式是 LCD/摄像头模式的两个子模式。I2S0 可以直接路由到内部模数转换器 (ADC) 和数模转换器 (DAC)，也即 ADC 和 DAC 外设可以通过 I2S0 的 DMA 连续读取或写入数据。由于 ADC 和 DAC 并非通信模式，因此并没有在 I2S 驱动中实现。 + +功能概览 +-------- + +I2S 驱动提供以下服务： + +资源管理 +^^^^^^^^ + +I2S 驱动中的资源可分为三个级别： + +- ``平台级资源``：当前芯片中所有 I2S 控制器的资源。 +- ``控制器级资源``：一个 I2S 控制器的资源。 +- ``通道级资源``：一个 I2S 控制器 TX 或 RX 通道的资源。 + +公开的 API 都是通道级别的 API，通道句柄 :cpp:type:`i2s_chan_handle_t` 可以帮助用户管理特定通道下的资源，而无需考虑其他两个级别的资源。高级别资源为私有资源，由驱动自动管理。用户可以调用 :cpp:func:`i2s_new_channel` 来分配通道句柄，或调用 :cpp:func:`i2s_del_channel` 来删除该句柄。 + +电源管理 +^^^^^^^^ + +电源管理启用（即开启 :ref:`CONFIG_PM_ENABLE`）时，系统将在进入 Light-sleep 前调整或停止 I2S 时钟源，这可能会影响 I2S 信号，从而导致传输或接收的数据无效。 + +I2S 驱动可以获取电源管理锁，从而防止系统设置更改或时钟源被禁用。时钟源为 APB 时，锁的类型将被设置为 :cpp:enumerator:`esp_pm_lock_type_t::ESP_PM_APB_FREQ_MAX`。时钟源为 APLL（若支持）时，锁的类型将被设置为 :cpp:enumerator:`esp_pm_lock_type_t::ESP_PM_NO_LIGHT_SLEEP`。用户通过 I2S 读写时（即调用 :cpp:func:`i2s_channel_read` 或 :cpp:func:`i2s_channel_write`），驱动程序将获取电源管理锁，并在读写完成后释放锁。 + +有限状态机 +^^^^^^^^^^ + +I2S 通道有三种状态，分别为 ``registered（已注册）``、 ``ready（准备就绪）`` 和 ``running（运行中）``，它们的关系如下图所示： + +.. figure:: ../../../_static/diagrams/i2s/i2s_state_machine.png + :align: center + :alt: I2S 有限状态机 + + I2S 有限状态机 + +图中的 ```` 可用相应的 I2S 通信模式来代替，如 ``std`` 代表标准的双声道模式。更多关于通信模式的信息，请参考 :ref:`i2s-communication-mode` 小节。 + +数据传输 +^^^^^^^^ + +I2S 的数据传输（包括数据发送和接收）由 DMA 实现。在传输数据之前，请调用 :cpp:func:`i2s_channel_enable` 来启用特定的通道。发送或接收的数据达到 DMA 缓冲区的大小时，将触发 ``I2S_OUT_EOF`` 或 ``I2S_IN_SUC_EOF`` 中断。注意，DMA 缓冲区的大小不等于 :cpp:member:`i2s_chan_config_t::dma_frame_num`，这里的一帧是指一个 WS 周期内的所有采样数据。因此， ``dma_buffer_size = dma_frame_num * slot_num * slot_bit_width / 8``。传输数据时，可以调用 :cpp:func:`i2s_channel_write` 来输入数据，并把数据从源缓冲区复制到 DMA TX 缓冲区等待传输完成。此过程将重复进行，直到发送的字节数达到配置的大小。接收数据时，用户可以调用函数 :cpp:func:`i2s_channel_read` 来等待接收包含 DMA 缓冲区地址的消息队列，从而将数据从 DMA RX 缓冲区复制到目标缓冲区。 + +:cpp:func:`i2s_channel_write` 和 :cpp:func:`i2s_channel_read` 都是阻塞函数，在源缓冲区的数据发送完毕前，或是整个目标缓冲区都被加载数据占用时，它们会一直保持等待状态。在等待时间达到最大阻塞时间时，返回 `ESP_ERR_TIMEOUT` 错误。要实现异步发送或接收数据，可以通过 :cpp:func:`i2s_channel_register_event_callback` 注册回调，随即便可在回调函数中直接访问 DMA 缓冲区，无需通过这两个阻塞函数来发送或接收数据。但请注意，该回调是一个中断回调，不要在该回调中添加复杂的逻辑、进行浮点运算或调用不可重入函数。 + +配置 +^^^^ + +用户可以通过调用相应函数（即 :func:`i2s_channel_init_std_mode`、 :func:`i2s_channel_init_pdm_rx_mode`、 :func:`i2s_channel_init_pdm_tx_mode` 或 :func:`i2s_channel_init_tdm_mode`）将通道初始化为特定模式。如果初始化后需要更新配置，必须先调用 :cpp:func:`i2s_channel_disable` 以确保通道已经停止运行，然后再调用相应的 'reconfig' 函数，例如 :cpp:func:`i2s_channel_reconfig_std_slot`、 :cpp:func:`i2s_channel_reconfig_std_clock` 和 :cpp:func:`i2s_channel_reconfig_std_gpio`。 + +IRAM 安全 +^^^^^^^^^ + +默认情况下，由于写入或擦除 flash 等原因导致 cache 被禁用时，I2S 中断将产生延迟，无法及时执行 EOF 中断。 + +在实时应用中，可通过启用 Kconfig 选项 :ref:`CONFIG_I2S_ISR_IRAM_SAFE` 来避免此种情况发生，启用后： + +1. 即使在 cache 被禁用的情况下，中断仍可继续运行。 + +2. 驱动程序将存放进 DRAM 中（以防其意外映射到 PSRAM 中）。 + +启用该选项可以保证 cache 禁用时的中断运行，但会相应增加 IRAM 占用。 + +线程安全 +^^^^^^^^ + +驱动程序可保证所有公开的 I2S API 的线程安全，使用时，可以直接从不同的 RTOS 任务中调用此类 API，无需额外锁保护。注意，I2S 驱动使用 mutex 锁来保证线程安全，因此不允许在 ISR 中使用这些 API。 + +Kconfig 选项 +^^^^^^^^^^^^ + +- :ref:`CONFIG_I2S_ISR_IRAM_SAFE` 控制默认 ISR 处理程序能否在禁用 cache 的情况下工作。更多信息可参考 `IRAM 安全 <#iram-safe>`__。 +- :ref:`CONFIG_I2S_SUPPRESS_DEPRECATE_WARN` 控制是否在使用原有 I2S 驱动时关闭警告信息。 +- :ref:`CONFIG_I2S_ENABLE_DEBUG_LOG` 用于启用调试日志输出。启用该选项将增加固件的二进制文件大小。 + +应用实例 +-------- + +I2S 驱动例程请参考 :example:`peripherals/i2s` 目录。以下为每种模式的简单用法： + +标准 TX/RX 模式的应用 +^^^^^^^^^^^^^^^^^^^^^ + +不同声道的通信格式可通过以下标准模式的辅助宏来生成。如上所述，在标准模式下有三种格式，辅助宏分别为： + +- :c:macro:`I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG` +- :c:macro:`I2S_STD_PCM_SLOT_DEFAULT_CONFIG` +- :c:macro:`I2S_STD_MSB_SLOT_DEFAULT_CONFIG` + +时钟配置的辅助宏为： + +- :c:macro:`I2S_STD_CLK_DEFAULT_CONFIG`。 + +请参考 :ref:`i2s-api-reference-i2s_std` 了解 STD API 的相关信息。更多细节请参考 :component_file:`driver/i2s/include/driver/i2s_std.h`。 + +STD TX 模式 +~~~~~~~~~~~~~ + +以 16 位数据位宽为例，如果 ``uint16_t`` 写缓冲区中的数据如下所示： + ++--------+--------+--------+--------+--------+--------+--------+--------+--------+ +| 数据 0 | 数据 1 | 数据 2 | 数据 3 | 数据 4 | 数据 5 | 数据 6 | 数据 7 | ... | ++========+========+========+========+========+========+========+========+========+ +| 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | ... | ++--------+--------+--------+--------+--------+--------+--------+--------+--------+ + +下表展示了在不同 :cpp:member:`i2s_std_slot_config_t::slot_mode` 和 :cpp:member:`i2s_std_slot_config_t::slot_mask` 设置下线路上的真实数据。 + +.. only:: esp32 + + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 数据位宽 | 声道模式 | 声道掩码 | WS 低电平| WS 高电平| WS 低电平| WS 高电平| WS 低电平| WS 高电平| WS 低电平| WS 高电平| + +================+===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ + | | 单声道 | 左 | 0x0002 | 0x0000 | 0x0001 | 0x0000 | 0x0004 | 0x0000 | 0x0003 | 0x0000 | + | 16 位 | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 右 | 0x0000 | 0x0002 | 0x0000 | 0x0001 | 0x0000 | 0x0004 | 0x0000 | 0x0003 | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 左右 | 0x0002 | 0x0002 | 0x0001 | 0x0001 | 0x0004 | 0x0004 | 0x0003 | 0x0003 | + | +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 立体声 | 左 | 0x0001 | 0x0001 | 0x0003 | 0x0003 | 0x0005 | 0x0005 | 0x0007 | 0x0007 | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 右 | 0x0002 | 0x0002 | 0x0004 | 0x0004 | 0x0006 | 0x0006 | 0x0008 | 0x0008 | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 左右 | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + + .. note:: + + 当数据位宽为 32 位时，情况与上表类似，但当位宽为 8 位和 24 位时需要额外注意。数据位宽为 8 时，写入的缓冲区仍应使用 ``uint16_t`` （即以 2 字节对齐），并且只有高 8 位有效，低 8 位将被丢弃；数据位宽为 24 时，缓冲区应该使用 ``uint32_t`` （ 即以 4 字节对齐），并且只有高 24 位有效，低 8 位将被丢弃。 + + 另外，在 8 位宽和 16 位宽单声道模式下，线路上的真实数据顺序会被调换。为了获取正确的数据顺序，写入缓冲区时，每两个字节需要调换一次数据顺序。 + +.. only:: esp32s2 + + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 数据位宽 | 声道模式 | 声道掩码 | WS 低电平| WS 高电平| WS 低电平| WS 高电平| WS 低电平| WS 高电平| WS 低电平| WS 高电平| + +================+===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ + | | 单声道 | 左 | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | 0x0000 | + | 16 位 | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 右 | 0x0000 | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 左右 | 0x0001 | 0x0001 | 0x0002 | 0x0002 | 0x0003 | 0x0003 | 0x0004 | 0x0004 | + | +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 立体声 | 左 | 0x0001 | 0x0001 | 0x0003 | 0x0003 | 0x0005 | 0x0005 | 0x0007 | 0x0007 | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 右 | 0x0002 | 0x0002 | 0x0004 | 0x0004 | 0x0006 | 0x0006 | 0x0008 | 0x0008 | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 左右 | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + + .. note:: + + 数据位宽为 8 位和 32 位时，缓冲区的类型最好为 ``uint8_t`` 和 ``uint32_t``。但需注意，数据位宽为 24 位时，数据缓冲区应该以 3 字节对齐，即每 3 个字节代表一个 24 位数据，另外，:cpp:member:`i2s_chan_config_t::dma_frame_num`、 :cpp:member:`i2s_std_clk_config_t::mclk_multiple` 和写缓冲区的大小应该为 ``3`` 的倍数，否则线路上的数据或采样率可能会不准确。 + +.. only:: not (esp32 or esp32s2) + + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 数据位宽 | 声道模式 | 声道掩码 | WS 低电平| WS 高电平| WS 低电平| WS 高电平| WS 低电平| WS 高电平| WS 低电平| WS 高电平| + +================+===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ + | | 单声道 | 左 | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | 0x0000 | + | 16 位 | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 右 | 0x0000 | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 左右 | 0x0001 | 0x0001 | 0x0002 | 0x0002 | 0x0003 | 0x0003 | 0x0004 | 0x0004 | + | +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 立体声 | 左 | 0x0001 | 0x0001 | 0x0003 | 0x0003 | 0x0005 | 0x0005 | 0x0007 | 0x0007 | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 右 | 0x0002 | 0x0002 | 0x0004 | 0x0004 | 0x0006 | 0x0006 | 0x0008 | 0x0008 | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | | 左右 | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + + .. note:: + + 数据位宽为 8 位和 32 位时，缓冲区的类型最好为 ``uint8_t`` 和 ``uint32_t``。但需注意，数据位宽为 24 位时，数据缓冲区应该以 3 字节对齐，即每 3 个字节代表一个 24 位数据，另外，:cpp:member:`i2s_chan_config_t::dma_frame_num`、 :cpp:member:`i2s_std_clk_config_t::mclk_multiple` 和写缓冲区的大小应该为 ``3`` 的倍数，否则线路上的数据或采样率可能会不准确。 + +.. code-block:: c + + #include "driver/i2s_std.h" + #include "driver/gpio.h" + + i2s_chan_handle_t tx_handle; + /* 通过辅助宏获取默认的通道配置 + * 这个辅助宏在 'i2s_common.h' 中定义，由所有 I2S 通信模式共享 + * 它可以帮助指定 I2S 角色和端口 ID */ + i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER); + /* 分配新的 TX 通道并获取该通道的句柄 */ + i2s_new_channel(&chan_cfg, &tx_handle, NULL); + + /* 进行配置，可以通过宏生成声道配置和时钟配置 + * 这两个辅助宏在 'i2s_std.h' 中定义，只能用于 STD 模式 + * 它们可以帮助初始化或更新声道和时钟配置 */ + i2s_std_config_t std_cfg = { + .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(48000), + .slot_cfg = I2S_STD_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_32BIT, I2S_SLOT_MODE_STEREO), + .gpio_cfg = { + .mclk = I2S_GPIO_UNUSED, + .bclk = GPIO_NUM_4, + .ws = GPIO_NUM_5, + .dout = GPIO_NUM_18, + .din = I2S_GPIO_UNUSED, + .invert_flags = { + .mclk_inv = false, + .bclk_inv = false, + .ws_inv = false, + }, + }, + }; + /* 初始化通道 */ + i2s_channel_init_std_mode(tx_handle, &std_cfg); + + /* 在写入数据之前，先启用 TX 通道 */ + i2s_channel_enable(tx_handle); + i2s_channel_write(tx_handle, src_buf, bytes_to_write, bytes_written, ticks_to_wait); + + /* 如果需要更新声道或时钟配置 + * 需要在更新前先禁用通道 */ + // i2s_channel_disable(tx_handle); + // std_cfg.slot_cfg.slot_mode = I2S_SLOT_MODE_MONO; // 默认为立体声 + // i2s_channel_reconfig_std_slot(tx_handle, &std_cfg.slot_cfg); + // std_cfg.clk_cfg.sample_rate_hz = 96000; + // i2s_channel_reconfig_std_clock(tx_handle, &std_cfg.clk_cfg); + + /* 删除通道之前必须先禁用通道 */ + i2s_channel_disable(tx_handle); + /* 如果不再需要句柄，删除该句柄以释放通道资源 */ + i2s_del_channel(tx_handle); + +STD RX 模式 +~~~~~~~~~~~~ + +例如，当数据位宽为 16 时，如线路上的数据如下所示： + ++----------+----------+----------+----------+----------+----------+----------+----------+----------+ +| WS 低电平| WS 高电平| WS 低电平| WS 高电平| WS 低电平| WS 高电平| WS 低电平| WS 高电平| ... | ++==========+==========+==========+==========+==========+==========+==========+==========+==========+ +| 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | ... | ++----------+----------+----------+----------+----------+----------+----------+----------+----------+ + +不同 :cpp:member:`i2s_std_slot_config_t::slot_mode` 和 :cpp:member:`i2s_std_slot_config_t::slot_mask` 配置下缓冲区中收到的数据如下所示。 + +.. only:: esp32 + + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 数据位宽 | 声道模式 | 声道掩码 | 数据 0 | 数据 1 | 数据 2 | 数据 3 | 数据 4 | 数据 5 | 数据 6 | 数据 7 | + +================+===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ + | | 单声道 | 左 | 0x0001 | 0x0000 | 0x0005 | 0x0003 | 0x0009 | 0x0007 | 0x000d | 0x000b | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 16 位 | | 右 | 0x0002 | 0x0000 | 0x0006 | 0x0004 | 0x000a | 0x0008 | 0x000e | 0x000c | + | +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 立体声 | 任意 | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + + .. note:: + + ESP32 上的接收有些复杂。首先，当数据位宽为 8 位或 24 位时，接收的数据仍将以 2 个字节或 4 个字节对齐，这意味着有效数据被放在每两个字节的高 8 位和每四个字节的高 24 位。例如，当线路上的数据是 8 位宽度的 ``0x5A`` 时，接收的数据将是 ``0x5A00``；当数据是 ``0x00 005A`` 时，则收到 ``0x0000 5A00``。其次，在 8 位宽和 16 位宽单声道传输中，缓冲区内每两个数据会进行一次数据翻转，因此可能需要手动将顺序回转，以获取正确的数据顺序。 + +.. only:: esp32s2 + + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 数据位宽 | 声道模式 | 声道掩码 | 数据 0 | 数据 1 | 数据 2 | 数据 3 | 数据 4 | 数据 5 | 数据 6 | 数据 7 | + +================+===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ + | | 单声道 | 左 | 0x0001 | 0x0003 | 0x0005 | 0x0007 | 0x0009 | 0x000b | 0x000d | 0x000f | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 16 位 | | 右 | 0x0002 | 0x0004 | 0x0006 | 0x0008 | 0x000a | 0x000c | 0x000e | 0x0010 | + | +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 立体声 | 任意 | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + + .. note:: + + 8 位、24 位和 32 位与 16 位的情况类似，接收缓冲区的数据位宽与线路上的数据位宽相等。此外需注意，数据位宽为 24 位时， :cpp:member:`i2s_chan_config_t::dma_frame_num`、 :cpp:member:`i2s_std_clk_config_t::mclk_multiple` 和接收缓冲区的大小应该为 ``3`` 的倍数，否则线路上的数据或采样率可能会不准确。 + +.. only:: not (esp32 or esp32s2) + + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 数据位宽 | 声道模式 | 声道掩码 | 数据 0 | 数据 1 | 数据 2 | 数据 3 | 数据 4 | 数据 5 | 数据 6 | 数据 7 | + +================+===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ + | | 单声道 | 左 | 0x0001 | 0x0003 | 0x0005 | 0x0007 | 0x0009 | 0x000b | 0x000d | 0x000f | + | | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 16 位 | | 右 | 0x0002 | 0x0004 | 0x0006 | 0x0008 | 0x000a | 0x000c | 0x000e | 0x0010 | + | +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 立体声 | 任意 | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | + +----------------+-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + + .. note:: + + 8 位、24 位和 32 位与 16 位的情况类似，接收缓冲区的数据位宽与线路上的数据位宽相等。此外需注意，数据位宽为 24 位时， :cpp:member:`i2s_chan_config_t::dma_frame_num`、 :cpp:member:`i2s_std_clk_config_t::mclk_multiple` 和接收缓冲区的大小应该为 ``3`` 的倍数，否则线路上的数据或采样率可能会不准确。 + +.. code-block:: c + + #include "driver/i2s_std.h" + #include "driver/gpio.h" + + i2s_chan_handle_t rx_handle; + /* 通过辅助宏获取默认的通道配置 + * 这个辅助宏在 'i2s_common.h' 中定义，由所有 I2S 通信模式共享 + * 它可以帮助指定 I2S 角色和端口 ID */ + i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER); + /* 分配新的 TX 通道并获取该通道的句柄 */ + i2s_new_channel(&chan_cfg, NULL, &rx_handle); + + /* 进行配置，可以通过宏生成声道配置和时钟配置 + * 这两个辅助宏在 'i2s_std.h' 中定义，只能用于 STD 模式 + * 它们可以帮助初始化或更新声道和时钟配置 */ + i2s_std_config_t std_cfg = { + .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(48000), + .slot_cfg = I2S_STD_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_32BIT, I2S_SLOT_MODE_STEREO), + .gpio_cfg = { + .mclk = I2S_GPIO_UNUSED, + .bclk = GPIO_NUM_4, + .ws = GPIO_NUM_5, + .dout = I2S_GPIO_UNUSED, + .din = GPIO_NUM_19, + .invert_flags = { + .mclk_inv = false, + .bclk_inv = false, + .ws_inv = false, + }, + }, + }; + /* 初始化通道 */ + i2s_channel_init_std_mode(rx_handle, &std_cfg); + + /* 在读取数据之前，先启动 RX 通道 */ + i2s_channel_enable(rx_handle); + i2s_channel_read(rx_handle, desc_buf, bytes_to_read, bytes_read, ticks_to_wait); + + /* 删除通道之前必须先禁用通道 */ + i2s_channel_disable(rx_handle); + /* 如果不再需要句柄，删除该句柄以释放通道资源 */ + i2s_del_channel(rx_handle); + + +.. only:: SOC_I2S_SUPPORTS_PDM_TX + + PDM TX 模式的应用 + ^^^^^^^^^^^^^^^^^^^ + + 针对 TX 通道的 PDM 模式，声道配置的辅助宏为： + + - :c:macro:`I2S_PDM_TX_SLOT_DEFAULT_CONFIG` + + 时钟配置的辅助宏为： + + - :c:macro:`I2S_PDM_TX_CLK_DEFAULT_CONFIG` + + PDM TX API 的相关信息，可参考 :ref:`i2s-api-reference-i2s_pdm`。更多细节请参阅 :component_file:`driver/i2s/include/driver/i2s_pdm.h`。 + + PDM 数据位宽固定为 16 位。如果 ``int16_t`` 写缓冲区中的数据如下： + + +--------+--------+--------+--------+--------+--------+--------+--------+--------+ + | 数据 0 | 数据 1 | 数据 2 | 数据 3 | 数据 4 | 数据 5 | 数据 6 | 数据 7 | ... | + +========+========+========+========+========+========+========+========+========+ + | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | ... | + +--------+--------+--------+--------+--------+--------+--------+--------+--------+ + + .. only:: esp32 + + 下表展示了不同 :cpp:member:`i2s_pdm_tx_slot_config_t::slot_mode` 和 :cpp:member:`i2s_pdm_tx_slot_config_t::slot_mask` 设置下线路上的真实数据。为方便理解，已将线路上的数据格式由 PDM 转为 PCM。 + + +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 声道模式 | 声道掩码 | 左 | 右 | 左 | 右 | 左 | 右 | 左 | 右 | + +===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ + | 单声道 | 左 | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | 0x0000 | + | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 右 | 0x0000 | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | + | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 左右 | 0x0001 | 0x0001 | 0x0002 | 0x0002 | 0x0003 | 0x0003 | 0x0004 | 0x0004 | + +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 立体声 | 左 | 0x0001 | 0x0001 | 0x0003 | 0x0003 | 0x0005 | 0x0005 | 0x0007 | 0x0007 | + | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 右 | 0x0002 | 0x0002 | 0x0004 | 0x0004 | 0x0006 | 0x0006 | 0x0008 | 0x0008 | + | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 左右 | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | + +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + + .. only:: not esp32 + + 下表展示了不同 :cpp:member:`i2s_pdm_tx_slot_config_t::slot_mode` 和 :cpp:member:`i2s_pdm_tx_slot_config_t::slot_mask` 设置下线路上的真实数据。为方便理解，已将线路上的数据格式由 PDM 转为 PCM。 + + +----------------+-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ + | 线路模式 | 声道模式 | 线路 | 左 | 右 | 左 | 右 | 左 | 右 | 左 | 右 | + +================+===========+======+========+========+========+========+========+========+========+========+ + | | 单声道 | dout | 0x0001 | 0x0000 | 0x0002 | 0x0000 | 0x0003 | 0x0000 | 0x0004 | 0x0000 | + | 单线 Codec +-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ + | | 立体声 | dout | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | + +----------------+-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ + | 单线 DAC | 单声道 | dout | 0x0001 | 0x0001 | 0x0002 | 0x0002 | 0x0003 | 0x0003 | 0x0004 | 0x0004 | + +----------------+-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ + | | 单声道 | dout | 0x0002 | 0x0002 | 0x0004 | 0x0004 | 0x0006 | 0x0006 | 0x0008 | 0x0008 | + | | +------+--------+--------+--------+--------+--------+--------+--------+--------+ + | | | dout2| 0x0000 | 0x0000 | 0x0000 | 0x0000 | 0x0000 | 0x0000 | 0x0000 | 0x0000 | + | 双线 DAC +-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ + | | 立体声 | dout | 0x0002 | 0x0002 | 0x0004 | 0x0004 | 0x0006 | 0x0006 | 0x0008 | 0x0008 | + | | +------+--------+--------+--------+--------+--------+--------+--------+--------+ + | | | dout2| 0x0001 | 0x0001 | 0x0003 | 0x0003 | 0x0005 | 0x0005 | 0x0007 | 0x0007 | + +----------------+-----------+------+--------+--------+--------+--------+--------+--------+--------+--------+ + + .. note:: + + PDM TX 模式有三种线路模式，分别为 ``I2S_PDM_TX_ONE_LINE_CODEC``、 ``I2S_PDM_TX_ONE_LINE_DAC`` 和 ``I2S_PDM_TX_TWO_LINE_DAC``。单线 Codec 用于需要时钟信号的 PDM 编解码器，PDM 编解码器可以通过时钟电平来区分左右声道。另外两种模式可通过低通滤波器直接驱动功率放大器，而无需时钟信号，所以有两条线路来区分左右声道。此外，对于单线 Codec 的单声道模式，可以通过在 GPIO 配置中设置时钟反转标志，强制将声道改变为右声道。 + + + .. code-block:: c + + #include "driver/i2s_pdm.h" + #include "driver/gpio.h" + + /* 分配 I2S TX 通道 */ + i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_0, I2S_ROLE_MASTER); + i2s_new_channel(&chan_cfg, &tx_handle, NULL); + + /* 初始化通道为 PDM TX 模式 */ + i2s_pdm_tx_config_t pdm_tx_cfg = { + .clk_cfg = I2S_PDM_TX_CLK_DEFAULT_CONFIG(36000), + .slot_cfg = I2S_PDM_TX_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_MONO), + .gpio_cfg = { + .clk = GPIO_NUM_5, + .dout = GPIO_NUM_18, + .invert_flags = { + .clk_inv = false, + }, + }, + }; + i2s_channel_init_pdm_tx_mode(tx_handle, &pdm_tx_cfg); + + ... + + +.. only:: SOC_I2S_SUPPORTS_PDM_RX + + PDM RX 模式的应用 + ^^^^^^^^^^^^^^^^^^ + + 针对 RX 通道的 PDM 模式，声道配置的辅助宏为： + + - :c:macro:`I2S_PDM_RX_SLOT_DEFAULT_CONFIG` + + 时钟配置的辅助宏为： + + - :c:macro:`I2S_PDM_RX_CLK_DEFAULT_CONFIG` + + PDM RX API 的相关信息，可参考 :ref:`i2s-api-reference-i2s_pdm`。更多细节请参阅 :component_file:`driver/i2s/include/driver/i2s_pdm.h`。 + + PDM 数据位宽固定为 16 位。如果线路上的数据如下所示。为方便理解，已将线路上的数据格式由 PDM 转为 PCM。 + + +--------+--------+--------+--------+--------+--------+--------+--------+--------+ + | 左 | 右 | 左 | 右 | 左 | 右 | 左 | 右 | ... | + +========+========+========+========+========+========+========+========+========+ + | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | ... | + +--------+--------+--------+--------+--------+--------+--------+--------+--------+ + + 下表展示了不同 :cpp:member:`i2s_pdm_rx_slot_config_t::slot_mode` 和 :cpp:member:`i2s_pdm_rx_slot_config_t::slot_mask` 设置下 'int16_t' 缓冲区接收的数据。 + + .. only:: esp32 + + +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 声道模式 | 声道掩码 | 数据 0 | 数据 1 | 数据 2 | 数据 3 | 数据 4 | 数据 5 | 数据 6 | 数据 7 | + +===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ + | 单声道 | 左 | 0x0001 | 0x0003 | 0x0005 | 0x0007 | 0x0009 | 0x000b | 0x000d | 0x000f | + | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 右 | 0x0002 | 0x0004 | 0x0006 | 0x0008 | 0x000a | 0x000c | 0x000e | 0x0010 | + +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 立体声 | 左右 | 0x0001 | 0x0002 | 0x0003 | 0x0004 | 0x0005 | 0x0006 | 0x0007 | 0x0008 | + +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + + .. only:: esp32s3 + + +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 声道模式 | 声道掩码 | 数据 0 | 数据 1 | 数据 2 | 数据 3 | 数据 4 | 数据 5 | 数据 6 | 数据 7 | + +===========+===========+==========+==========+==========+==========+==========+==========+==========+==========+ + | 单声道 | 左 | 0x0001 | 0x0003 | 0x0005 | 0x0007 | 0x0009 | 0x000b | 0x000d | 0x000f | + | +-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | | 右 | 0x0002 | 0x0004 | 0x0006 | 0x0008 | 0x000a | 0x000c | 0x000e | 0x0010 | + +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + | 立体声 | 左右 | 0x0002 | 0x0001 | 0x0004 | 0x0003 | 0x0006 | 0x0005 | 0x0008 | 0x0007 | + +-----------+-----------+----------+----------+----------+----------+----------+----------+----------+----------+ + + .. note:: + + 在立体声模式下，右声道先被接收。如需切换缓冲区中的左右声道，可设置 :cpp:member:`i2s_pdm_rx_gpio_config_t::invert_flags::clk_inv` 来强制反转时钟信号。 + + ESP32-S3 在 PDM RX 模式下最多可以支持四条数据线，每条数据线可以连接到两个 PDM MIC 的左右两个声道，这意味着 ESP32-S3 的 PDM RX 模式最多可以支持八个 PDM MIC。如需启用多条数据线，可设置 :cpp:member:`i2s_pdm_rx_gpio_config_t::slot_mask` 中相应的位来启用相应声道，然后设置 :cpp:type:`i2s_pdm_rx_gpio_config_t` 中的数据 GPIO。 + + .. code-block:: c + + #include "driver/i2s_pdm.h" + #include "driver/gpio.h" + + i2s_chan_handle_t rx_handle; + + /* 分配 I2S RX 通道 */ + i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_0, I2S_ROLE_MASTER); + i2s_new_channel(&chan_cfg, NULL, &rx_handle); + + /* 初始化通道为 PDM RX 模式 */ + i2s_pdm_rx_config_t pdm_rx_cfg = { + .clk_cfg = I2S_PDM_RX_CLK_DEFAULT_CONFIG(36000), + .slot_cfg = I2S_PDM_RX_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_MONO), + .gpio_cfg = { + .clk = GPIO_NUM_5, + .din = GPIO_NUM_19, + .invert_flags = { + .clk_inv = false, + }, + }, + }; + i2s_channel_init_pdm_rx_mode(rx_handle, &pdm_rx_cfg); + + ... + + +.. only:: SOC_I2S_SUPPORTS_TDM + + TDM TX/RX 模式的应用 + ^^^^^^^^^^^^^^^^^^^^^ + + 可以通过以下 TDM 模式的辅助宏生成不同的声道通信格式。如上所述，TDM 模式有四种格式，它们的辅助宏分别为： + + - :c:macro:`I2S_TDM_PHILIPS_SLOT_DEFAULT_CONFIG` + - :c:macro:`I2S_TDM_MSB_SLOT_DEFAULT_CONFIG` + - :c:macro:`I2S_TDM_PCM_SHORT_SLOT_DEFAULT_CONFIG` + - :c:macro:`I2S_TDM_PCM_LONG_SLOT_DEFAULT_CONFIG` + + 时钟配置的辅助宏为： + + - :c:macro:`I2S_TDM_CLK_DEFAULT_CONFIG` + + 有关 TDM API 的信息，请参阅 :ref:`i2s-api-reference-i2s_tdm`。更多细节请参阅 :component_file:`driver/i2s/include/driver/i2s_tdm.h`。 + + .. note:: + + 在为从机配置时钟时，由于硬件限制，请注意 :cpp:member:`i2s_tdm_clk_config_t::bclk_div` 不应小于 8，增加此字段的值可以减少从机发送数据的延迟。使用高采样率时，数据可能会延迟一个 BCLK 周期以上，这将导致数据错位。可以通过缓慢增加 :cpp:member:`i2s_tdm_clk_config_t::bclk_div` 的值来进行校正。 + + 由于 :cpp:member:`i2s_tdm_clk_config_t::bclk_div` 是 MCLK 基于 BCLK 的除数，增加该值也可以提高 MCLK 频率。因此，如果 MCLK 频率太高，将会无法从源时钟分频，此时时钟计算可能会失败，也就是说 :cpp:member:`i2s_tdm_clk_config_t::bclk_div` 不是越大越好。 + + TDM TX 模式 + ~~~~~~~~~~~ + + .. code-block:: c + + #include "driver/i2s_tdm.h" + #include "driver/gpio.h" + + /* 分配 I2S TX 通道 */ + i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER); + i2s_new_channel(&chan_cfg, &tx_handle, NULL); + + /* 初始化通道为 TDM 模式 */ + i2s_tdm_config_t tdm_cfg = { + .clk_cfg = I2S_TDM_CLK_DEFAULT_CONFIG(44100), + .slot_cfg = I2S_TDM_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO, + I2S_TDM_SLOT0 | I2S_TDM_SLOT1 | I2S_TDM_SLOT2 | I2S_TDM_SLOT3), + .gpio_cfg = { + .mclk = I2S_GPIO_UNUSED, + .bclk = GPIO_NUM_4, + .ws = GPIO_NUM_5, + .dout = GPIO_NUM_18, + .din = I2S_GPIO_UNUSED, + .invert_flags = { + .mclk_inv = false, + .bclk_inv = false, + .ws_inv = false, + }, + }, + }; + i2s_channel_init_tdm_mode(tx_handle, &tdm_cfg); + + ... + + TDM RX 模式 + ~~~~~~~~~~~ + + .. code-block:: c + + #include "driver/i2s_tdm.h" + #include "driver/gpio.h" + + /* 将通道模式设置为 TDM */ + i2s_chan_config_t chan_cfg = I2S_CHANNEL_CONFIG(I2S_ROLE_MASTER, I2S_COMM_MODE_TDM, &i2s_pin); + i2s_new_channel(&chan_cfg, NULL, &rx_handle); + + /* 初始化通道为 TDM 模式 */ + i2s_tdm_config_t tdm_cfg = { + .clk_cfg = I2S_TDM_CLK_DEFAULT_CONFIG(44100), + .slot_cfg = I2S_TDM_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO, + I2S_TDM_SLOT0 | I2S_TDM_SLOT1 | I2S_TDM_SLOT2 | I2S_TDM_SLOT3), + .gpio_cfg = { + .mclk = I2S_GPIO_UNUSED, + .bclk = GPIO_NUM_4, + .ws = GPIO_NUM_5, + .dout = I2S_GPIO_UNUSED, + .din = GPIO_NUM_18, + .invert_flags = { + .mclk_inv = false, + .bclk_inv = false, + .ws_inv = false, + }, + }, + }; + i2s_channel_init_tdm_mode(rx_handle, &tdm_cfg); + ... + +全双工 +^^^^^^ + +全双工模式可以在 I2S 端口中同时注册 TX 和 RX 通道，同时通道共享 BCLK 和 WS 信号。目前，STD 和 TDM 通信模式支持以下方式的全双工通信，但不支持 PDM 全双工模式，因为 PDM 模式下 TX 和 RX 通道的时钟不同。 + +请注意，一个句柄只能代表一个通道，因此仍然需要对 TX 和 RX 通道逐个进行声道和时钟配置。 + +以下示例展示了如何分配两个全双工通道： + +.. code-block:: c + + #include "driver/i2s_std.h" + #include "driver/gpio.h" + + i2s_chan_handle_t tx_handle; + i2s_chan_handle_t rx_handle; + + /* 分配两个 I2S 通道 */ + i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER); + /* 同时分配给 TX 和 RX 通道，使其进入全双工模式。 */ + i2s_new_channel(&chan_cfg, &tx_handle, &rx_handle); + + /* 配置两个通道，因为在全双工模式下，TX 和 RX 通道必须相同。 */ + i2s_std_config_t std_cfg = { + .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(32000), + .slot_cfg = I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO), + .gpio_cfg = { + .mclk = I2S_GPIO_UNUSED, + .bclk = GPIO_NUM_4, + .ws = GPIO_NUM_5, + .dout = GPIO_NUM_18, + .din = GPIO_NUM_19, + .invert_flags = { + .mclk_inv = false, + .bclk_inv = false, + .ws_inv = false, + }, + }, + }; + i2s_channel_init_std_mode(tx_handle, &std_cfg); + i2s_channel_init_std_mode(rx_handle, &std_cfg); + + i2s_channel_enable(tx_handle); + i2s_channel_enable(rx_handle); + + ... + +.. only:: SOC_I2S_HW_VERSION_1 + + 单工模式 + ^^^^^^^^ + + 在单工模式下分配通道句柄，应该为每个通道调用 :cpp:func:`i2s_new_channel`。在 {IDF_TARGET_NAME} 上，TX/RX 通道的时钟和 GPIO 管脚不是相互独立的，因此在单工模式下，TX 和 RX 通道不能共存于同一个 I2S 端口中。 + + .. code-block:: c + + #include "driver/i2s_std.h" + #include "driver/gpio.h" + + i2s_chan_handle_t tx_handle; + i2s_chan_handle_t rx_handle; + + i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER); + i2s_new_channel(&chan_cfg, &tx_handle, NULL); + i2s_std_config_t std_tx_cfg = { + .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(48000), + .slot_cfg = I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO), + .gpio_cfg = { + .mclk = GPIO_NUM_0, + .bclk = GPIO_NUM_4, + .ws = GPIO_NUM_5, + .dout = GPIO_NUM_18, + .din = I2S_GPIO_UNUSED, + .invert_flags = { + .mclk_inv = false, + .bclk_inv = false, + .ws_inv = false, + }, + }, + }; + /* 初始化通道 */ + i2s_channel_init_std_mode(tx_handle, &std_tx_cfg); + i2s_channel_enable(tx_handle); + + /* 如果没有找到其他可用的 I2S 设备，RX 通道将被注册在另一个 I2S 上 + * 并返回 ESP_ERR_NOT_FOUND */ + i2s_new_channel(&chan_cfg, NULL, &rx_handle); + i2s_std_config_t std_rx_cfg = { + .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(16000), + .slot_cfg = I2S_STD_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_32BIT, I2S_SLOT_MODE_STEREO), + .gpio_cfg = { + .mclk = I2S_GPIO_UNUSED, + .bclk = GPIO_NUM_6, + .ws = GPIO_NUM_7, + .dout = I2S_GPIO_UNUSED, + .din = GPIO_NUM_19, + .invert_flags = { + .mclk_inv = false, + .bclk_inv = false, + .ws_inv = false, + }, + }, + }; + i2s_channel_init_std_mode(rx_handle, &std_rx_cfg); + i2s_channel_enable(rx_handle); + +.. only:: SOC_I2S_HW_VERSION_2 + + 单工模式 + ^^^^^^^^ + + 在单工模式下分配通道，应该为每个通道调用 :cpp:func:`i2s_new_channel`。{IDF_TARGET_NAME} 上，TX/RX 通道的时钟和 GPIO 管脚相互独立，因此可以配置为不同的模式和时钟，并且能够在单工模式下共存于同一个 I2S 端口中。对于 PDM 模式，用户可以通过在同一个 I2S 端口上注册 PDM TX 单工和 PDM RX 单工来实现 PDM 双工。但在这种情况下，PDM TX/RX 可能会使用不同的时钟，因此在配置 GPIO 管脚和时钟时需多加注意。 + + 以下为单工模式的示例。请注意，如果 TX 和 RX 通道来自同一个控制器，则 TX 和 RX 通道的内部 MCLK 信号虽然是分开的，但输出的 MCLK 信号只能绑定到其中一个通道。如果两个通道都初始化了 MCLK，则该信号会绑定到后初始化的通道。 + + .. code-block:: c + + #include "driver/i2s_std.h" + #include "driver/gpio.h" + + i2s_chan_handle_t tx_handle; + i2s_chan_handle_t rx_handle; + i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_0, I2S_ROLE_MASTER); + i2s_new_channel(&chan_cfg, &tx_handle, NULL); + i2s_std_config_t std_tx_cfg = { + .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(48000), + .slot_cfg = I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO), + .gpio_cfg = { + .mclk = GPIO_NUM_0, + .bclk = GPIO_NUM_4, + .ws = GPIO_NUM_5, + .dout = GPIO_NUM_18, + .din = I2S_GPIO_UNUSED, + .invert_flags = { + .mclk_inv = false, + .bclk_inv = false, + .ws_inv = false, + }, + }, + }; + /* 初始化通道 */ + i2s_channel_init_std_mode(tx_handle, &std_tx_cfg); + i2s_channel_enable(tx_handle); + + /* 如果没有找到其他可用的 I2S 设备，RX 通道将被注册在另一个 I2S 上 + * 并返回 ESP_ERR_NOT_FOUND */ + i2s_new_channel(&chan_cfg, NULL, &rx_handle); // RX 和 TX 通道都将注册在 I2S0 上，但配置可以不同 + i2s_std_config_t std_rx_cfg = { + .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(16000), + .slot_cfg = I2S_STD_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_32BIT, I2S_SLOT_MODE_STEREO), + .gpio_cfg = { + .mclk = I2S_GPIO_UNUSED, + .bclk = GPIO_NUM_6, + .ws = GPIO_NUM_7, + .dout = I2S_GPIO_UNUSED, + .din = GPIO_NUM_19, + .invert_flags = { + .mclk_inv = false, + .bclk_inv = false, + .ws_inv = false, + }, + }, + }; + i2s_channel_init_std_mode(rx_handle, &std_rx_cfg); + i2s_channel_enable(rx_handle); + + +应用注意事项 +------------ + +防止数据丢失 +^^^^^^^^^^^^ + +对于需要高频采样率的应用，数据的巨大吞吐量可能会导致数据丢失。用户可以通过注册 ISR 回调函数来接收事件队列中的数据丢失事件： + + .. code-block:: c + + static IRAM_ATTR bool i2s_rx_queue_overflow_callback(i2s_chan_handle_t handle, i2s_event_data_t *event, void *user_ctx) + { + // 处理 RX 队列溢出事件 ... + return false; + } + + i2s_event_callbacks_t cbs = { + .on_recv = NULL, + .on_recv_q_ovf = i2s_rx_queue_overflow_callback, + .on_sent = NULL, + .on_send_q_ovf = NULL, + }; + TEST_ESP_OK(i2s_channel_register_event_callback(rx_handle, &cbs, NULL)); + +请按照以下步骤操作，以防止数据丢失： + +1. 确定中断间隔。通常来说，当发生数据丢失时，为减少中断次数，中断间隔应该越久越好。因此，在保证 DMA 缓冲区大小不超过最大值 4092 的前提下，应使 ``dma_frame_num`` 尽可能大。具体转换关系如下:: + + interrupt_interval(unit: sec) = dma_frame_num / sample_rate + dma_buffer_size = dma_frame_num * slot_num * data_bit_width / 8 <= 4092 + +2. 确定 ``dma_desc_num`` 的值。``dma_desc_num`` 由 ``i2s_channel_read`` 轮询周期的最大时间决定，所有接收到的数据都应该存储在两个 ``i2s_channel_read`` 之间。这个周期可以通过计时器或输出 GPIO 信号来计算。具体转换关系如下:: + + dma_desc_num > polling_cycle / interrupt_interval + +3. 确定接收缓冲区大小。在 ``i2s_channel_read`` 中提供的接收缓冲区应当能够容纳所有 DMA 缓冲区中的数据，这意味着它应该大于所有 DMA 缓冲区的总大小:: + + recv_buffer_size > dma_desc_num * dma_buffer_size + +例如，如果某个 I2S 应用的已知值包括:: + + sample_rate = 144000 Hz + data_bit_width = 32 bits + slot_num = 2 + polling_cycle = 10 ms + +那么可以按照以下公式计算出参数 ``dma_frame_num``、 ``dma_desc_num`` 和 ``recv_buf_size``:: + + dma_frame_num * slot_num * data_bit_width / 8 = dma_buffer_size <= 4092 + dma_frame_num <= 511 + interrupt_interval = dma_frame_num / sample_rate = 511 / 144000 = 0.003549 s = 3.549 ms + dma_desc_num > polling_cycle / interrupt_interval = cell(10 / 3.549) = cell(2.818) = 3 + recv_buffer_size > dma_desc_num * dma_buffer_size = 3 * 4092 = 12276 bytes + + +API 参考 +-------- + +.. _i2s-api-reference-i2s_std: + +标准模式 +^^^^^^^^ + +.. include-build-file:: inc/i2s_std.inc + +.. only:: SOC_I2S_SUPPORTS_PDM + + .. _i2s-api-reference-i2s_pdm: + + PDM 模式 + ^^^^^^^^ + + .. include-build-file:: inc/i2s_pdm.inc + +.. only:: SOC_I2S_SUPPORTS_TDM + + .. _i2s-api-reference-i2s_tdm: + + TDM 模式 + ^^^^^^^^ + + .. include-build-file:: inc/i2s_tdm.inc + +.. _i2s-api-reference-i2s_driver: + +I2S 驱动 +^^^^^^^^ + +.. include-build-file:: inc/i2s_common.inc + +.. _i2s-api-reference-i2s_types: + +I2S 类型 +^^^^^^^^ + +.. include-build-file:: inc/components/driver/i2s/include/driver/i2s_types.inc +.. include-build-file:: inc/components/hal/include/hal/i2s_types.inc