(See the README.md file in the upper level 'examples' directory for more information about examples.)
I2S on `ESP32S3` and `ESP32C3` supports [TDM mode](https://docs.espressif.com/projects/esp-idf/en/latest/esp32s3/api-reference/peripherals/i2s.html#tdm-mode), in which multiple slots can be transmitted by standard I2S connection.
This example demonstrates how to use I2S TDM mode to record 4 MICs connected to [ES7210](http://www.everest-semi.com/pdf/ES7210%20PB.pdf) codec. ES7210 has 4 TDM modes, which are `ES7210_I2S_FMT_I2S``ES7210_I2S_FMT_LJ``ES7210_I2S_FMT_DSP_A` and `ES7210_I2S_FMT_DSP_B`, and they are all supported by I2S TDM driver. Relation between ES7210 TDM modes and I2S Driver TDM modes is shown in the following table.
Recorded voice will be saved to SD card in `wav` format, and can be played or processed on PC.
## How to Use Example
### Hardware Required
* A development board with any supported Espressif SOC chip (see `Supported Targets` table above)
* An ES7210 module with 4 MICs connected
* A SPI SD card module
* A SD card reader and a PC (if you want to play recorded voice)
All the GPIO used in this example can be changed according to your board, by macros `EXAMPLE_xxx_IO` defined at the beginning of [i2s_es7210_record_example.c](main/i2s_es7210_record_example.c).
This example is based on [es7210 component](https://components.espressif.com/component/espressif/es7210)
The component can be installed by esp component manager. Since this example already installed it, no need to re-installed it again, but if you want to install this component in your own project, you can input the following command:
```
idf.py add-dependency espressif/es7210^1.0.0
```
If the dependency is added, you can check `idf_component.yml` for more detail. When building this example or other projects with managed components, the component manager will search for the required components online and download them into the `managed_componets` folder.
* Set the target of the build by following command, where TARGET can be `esp32s3` or `esp32c3`.
```
idf.py set-target TARGET
```
* Change value of `EXAMPLE_I2S_FORMAT` to check I2S driver's functionality on different I2S formats.
* Change `EXAMPLE_ES7210_MIC_GAIN` and `EXAMPLE_ES7210_MIC_BIAS` accoirding your MIC's specs if needed.
* Change `EXAMPLE_ES7210_ADC_VOLUME` if recorded voice is too loud or too quite.
Note: it's better to adjust `EXAMPLE_ES7210_MIC_GAIN` first. If adjusting MIC gain doesn't meet your demand, you can then adjust `EXAMPLE_ES7210_ADC_VOLUME`. That is to say, it's better to adjust analog gain than digital gain.
### Build and Flash
Run `idf.py -p PORT flash monitor` to build, flash and monitor the project.
(To exit the serial monitor, type ``Ctrl-]``.)
See the [Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/latest/get-started/index.html) for full steps to configure and use ESP-IDF to build projects.
## Console Output
```
I (277) cpu_start: Starting scheduler.
I (281) example: Create I2S receive channel
I (281) example: Configure I2S receive channel to TDM mode
I (291) example: Init I2C used to configure ES7210
I (291) example: Configure ES7210 codec parameters
I (301) ES7210: format: standard i2s, bit width: 16, tdm mode enabled
I (311) ES7210: sample rate: 48000Hz, mclk frequency: 12288000Hz
