pioduino/esp-idf
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

driver/i2s: support mclk

Browse Source
This commit is contained in:
laokaiyao
2021-07-27 15:54:31 +08:00
parent 3c57a6ac36
commit f863998e90
17 changed files with 295 additions and 173 deletions
Download Patch File Download Diff File Expand all files Collapse all files
docs/en/api-reference/peripherals/i2s.rst
+17 -7
View File
@@ -12,6 +12,7 @@ I2S (Inter-IC Sound) is a serial, synchronous communication protocol that is usu
An I2S bus consists of the following lines:
- Master clock line (operational)
- Bit clock line
- Channel select line
- Serial data line
@@ -38,13 +39,15 @@ Each controller can operate in half-duplex communication mode. Thus, the two con
For more information, see *{IDF_TARGET_NAME} Technical Reference Manual* > *I2S Controller (I2S)* > LCD Mode [`PDF <{IDF_TARGET_TRM_EN_URL}#camlcdctrl>`__].
.. note::
.. only:: SOC_I2S_SUPPORTS_APLL
For high accuracy clock applications, use the APLL_CLK clock source, which has the frequency range of 16 ~ 128 MHz. You can enable the APLL_CLK clock source by setting :cpp:member:`i2s_config_t::use_apll` to ``TRUE``.
.. note::
If :cpp:member:`i2s_config_t::use_apll` = ``TRUE`` and :cpp:member:`i2s_config_t::fixed_mclk` > ``0``, then the master clock output frequency for I2S will be equal to the value of :cpp:member:`i2s_config_t::fixed_mclk`, which means that the mclk frequency is provided by the user, instead of being calculated by the driver.
For high accuracy clock applications, use the APLL_CLK clock source, which has the frequency range of 16 ~ 128 MHz. You can enable the APLL_CLK clock source by setting :cpp:member:`i2s_config_t::use_apll` to ``TRUE``.
The clock rate of the word select line, which is called audio left-right clock rate (LRCK) here, is always the divisor of the master clock output frequency and for which the following is always true: 0 < MCLK/LRCK/channels/bits_per_sample < 64.
If :cpp:member:`i2s_config_t::use_apll` = ``TRUE`` and :cpp:member:`i2s_config_t::fixed_mclk` > ``0``, then the master clock output frequency for I2S will be equal to the value of :cpp:member:`i2s_config_t::fixed_mclk`, which means that the mclk frequency is provided by the user, instead of being calculated by the driver.
The clock rate of the word select line, which is called audio left-right clock rate (LRCK) here, is always the divisor of the master clock output frequency and for which the following is always true: 0 < MCLK/LRCK/channels/bits_per_sample < 64.
Functional Overview
@@ -60,7 +63,7 @@ Install the I2S driver by calling the function :cpp:func`i2s_driver_install` and
- The structure :cpp:type:`i2s_config_t` with defined communication parameters
- Event queue size and handle
I2S will start automatically once :cpp:func`i2s_driver_install` returns ``ESP_OK``.
Once :cpp:func`i2s_driver_install` returns ``ESP_OK``, it means I2S has started.
Configuration example:
@@ -111,11 +114,16 @@ Setting Communication Pins
Once the driver is installed, configure physical GPIO pins to which signals will be routed. For this, call the function :cpp:func`i2s_set_pin` and pass the following arguments to it:
- Port number
- The structure :cpp:type:`i2s_pin_config_t` defining the GPIO pin numbers to which the driver should route the BCK, WS, DATA out, and DATA in signals. If you want to keep a currently allocated pin number for a specific signal, or if this signal is unused, then pass the macro :c:macro:`I2S_PIN_NO_CHANGE`. See the example below.
- The structure :cpp:type:`i2s_pin_config_t` defining the GPIO pin numbers to which the driver should route the MCK, BCK, WS, DATA out, and DATA in signals. If you want to keep a currently allocated pin number for a specific signal, or if this signal is unused, then pass the macro :c:macro:`I2S_PIN_NO_CHANGE`. See the example below.
.. note::
MCK only takes effect in `I2S_MODE_MASTER` mode.
.. code-block:: c
static const i2s_pin_config_t pin_config = {
.mck_io_num = 0,
.bck_io_num = 4,
.ws_io_num = 5,
.data_out_num = 18,
@@ -257,7 +265,9 @@ Example for general usage.
i2s_driver_uninstall(i2s_num); //stop & destroy i2s driver
I2S on {IDF_TARGET_NAME} support TDM mode, up to 16 channels are available in TDM mode. If you want to use TDM mode, set field ``channel_format`` of :cpp:type:`i2s_config_t` to ``I2S_CHANNEL_FMT_MULTIPLE``. Then enable the channels by setting ``tdm_chan_cfg.chan_mask`` using masks in :cpp:type:`i2s_channel_t`, the number of active channels and total channels will be calculate automatically. Also you can set a particular total channel number for it, but it shouldn't be smaller than the largest channel you use.
I2S on {IDF_TARGET_NAME} support TDM mode, up to 16 channels are available in TDM mode. If you want to use TDM mode, set field ``channel_format`` of :cpp:type:`i2s_config_t` to ``I2S_CHANNEL_FMT_MULTIPLE``. Then enable the channels by setting ``chan_mask`` using masks in :cpp:type:`i2s_channel_t`, the number of active channels and total channels will be calculate automatically. Also you can set a particular total channel number for it, but it shouldn't be smaller than the largest channel you use.
If active channels are discrete, the inactive channels within total channels will be filled by a constant automatically. But if ``skip_msk`` is enabled, these inactive channels will be skiped.
.. code-block:: c