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I2S TDM Example -- ES7210 4-Ch ADC Codec

examples/peripherals/i2s/i2s_codec/i2s_es7210_tdm/README.md

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Supported TargetsESP32-C3ESP32-C5ESP32-C6ESP32-C61ESP32-H2ESP32-H21ESP32-H4ESP32-P4ESP32-S3

I2S TDM Example -- ES7210 4-Ch ADC Codec

(See the README.md file in the upper level 'examples' directory for more information about examples.)

The targets that listed on the top support 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 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.

Mode of ES7210 TDMMode of I2S Driver TDM
ES7210_I2S_FMT_I2SPhilips format
ES7210_I2S_FMT_LJMSB format
ES7210_I2S_FMT_DSP_APCM short format
ES7210_I2S_FMT_DSP_BPCM long format

In this example, we use esp_codec_dev dependency which contains the es7210 driver. This driver uses ES7210_I2S_FMT_I2S format by default.

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.

Dependency

This example is based on esp_codec_dev component

The component can be installed by IDF Component Manager. This example already includes it. If you want to install esp_codec_dev component separately in your project, you can input the following command:

idf.py add-dependency "espressif/esp_codec_dev^1.3.4"

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_components folder.

Configure the project

  • Set the target of the build by following command, where TARGET can be esp32s3 or esp32c3.
idf.py set-target TARGET

The configuration macros are defined at the beginning of main/i2s_es7210_record_example.c, you can change the configuration macros according to your needs.

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 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
I (311) example: Initializing SPI bus for SD card
I (321) example: Mounting SD card
I (321) gpio: GPIO[4]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0
I (371) sdspi_transaction: cmd=5, R1 response: command not supported
I (381) example: Card size: 14772MB, speed: 20MHz
I (381) example: Opening file /RECORD.WAV
I (391) example: Recording: 1/10s
I (1401) example: Recording: 2/10s
I (2411) example: Recording: 3/10s
I (3401) example: Recording: 4/10s
I (4411) example: Recording: 5/10s
I (5411) example: Recording: 6/10s
I (6421) example: Recording: 7/10s
I (7411) example: Recording: 8/10s
I (8411) example: Recording: 9/10s
I (9401) example: Recording: 10/10s
I (10401) example: Recording done! Flushing file buffer
I (10431) gpio: GPIO[4]| InputEn: 1| OutputEn: 0| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0
I (10431) example: You can now safely remove the card, recorded file is /RECORD.WAV

Application Notes

TDM mode is widely used in multi-channel scenario. Some ADC/DAC (e.g., ES7210 and ES7243) that supports TDM can be cascaded to sample more channels synchronously.

Take ES7210 for example, it is a 4-channel audio ADC that supports TDM. And we can chain upto four ES7210 to form a 16-channel recorder, meanwhile it only needs one I2S port.

You can refer to the connection as follow:

┌───────────────┐
│      ESP      │
│               │
│          MCLK ├───────────┬──────────────────────────────┬──────────────────────────────┬──────────────────────────────┐
│               │           │                              │                              │                              │
│          BCLK ├────────┬──┼───────────────────────────┬──┼───────────────────────────┬──┼───────────────────────────┐  │
│               │        │  │                           │  │                           │  │                           │  │
│            WS ├─────┬──┼──┼────────────────────────┬──┼──┼────────────────────────┬──┼──┼────────────────────────┐  │  │
│               │     │  │  │                        │  │  │                        │  │  │                        │  │  │
│          DOUT │     │  │  │    ┌───────────────┐   │  │  │    ┌───────────────┐   │  │  │    ┌───────────────┐   │  │  │    ┌───────────────┐
│               │     │  │  │    │   ES7210_0    │   │  │  │    │   ES7210_1    │   │  │  │    │   ES7210_2    │   │  │  │    │   ES7210_3    │
│           DIN │◄─┐  │  │  │    │               │   │  │  │    │               │   │  │  │    │               │   │  │  │    │               │
└───────────────┘  │  │  │  └───►│ MCLK          │   │  │  └───►│ MCLK          │   │  │  └───►│ MCLK          │   │  │  └───►│ MCLK          │
                   │  │  │       │               │   │  │       │               │   │  │       │               │   │  │       │               │
                   │  │  └──────►│ SCLK          │   │  └──────►│ SCLK          │   │  └──────►│ SCLK          │   │  └──────►│ SCLK          │
                   │  │          │               │   │          │               │   │          │               │   │          │               │
                   │  └─────────►│ LRCK          │   └─────────►│ LRCK          │   └─────────►│ LRCK          │   └─────────►│ LRCK          │
                   │             │               │              │               │              │               │              │               │
                   └─────────────┤ TDMOUT        │   ┌──────────┤ TDMOUT        │   ┌──────────┤ TDMOUT        │   ┌──────────┤ TDMOUT        │
                                 │               │   │          │               │   │          │               │   │          │               │
                            ┌───►│ TDMIN         │   │     ┌───►│ TDMIN         │   │     ┌───►│ TDMIN         │   │          │ TDMIN         │
                            │    │               │   │     │    │               │   │     │    │               │   │          │               │
                            │    └───────────────┘   │     │    └───────────────┘   │     │    └───────────────┘   │          └───────────────┘
                            │                        │     │                        │     │                        │
                            └────────────────────────┘     └────────────────────────┘     └────────────────────────┘

How A Frame Formed in This Cascaded Case

Generally, all the ES7210 will send the data that sampled by itself at the beginning of a frame, and then catenate the backward ES7210 data behind. In another word, ES7210_0 will send the data in the order ES7210_0 -> ES7210_1 -> ES7210_2 -> ES7210_3.

See the detailed steps as follows:

  1. First 4 channels of the 16 channels:
    • ES7210_3 send data that sampled by itself to ES7210_2;
    • ES7210_2 send data that sampled by itself to ES7210_1, store the data sent from ES7210_3;
    • ES7210_1 send data that sampled by itself to ES7210_0, store the data sent from ES7210_2;
    • ES7210_0 send data that sampled by itself to ESP, store the data sent from ES7210_1;
  2. Second 4 channels of the 16 channels:
    • ES7210_2 send the stored data (i.e., sampled by ES7210_3) to ES7210_1;
    • ES7210_1 send the stored data (i.e., sampled by ES7210_2) to ES7210_0, and store the data from ES7210_2 (i.e., sampled by ES7210_3);
    • ES7210_0 send the stored data (i.e., sampled by ES7210_1) to ESP, and store the data sent from ES7210_1 (i.e., sampled by ES7210_2);
  3. Third 4 channels of the 16 channels:
    • ES7210_1 send the stored data (i.e., sampled by ES7210_3) to ES7210_0;
    • ES7210_0 send the stored data (i.e., sampled by ES7210_2) to ESP, and store the data from ES7210_1 (i.e., sampled by ES7210_3);
  4. Last 4 channels of the 16 channels:
    • ES7210_0 send the stored data (i.e., sampled by ES7210_3) to ESP;

Troubleshooting

For any technical queries, please open an issue on GitHub. We will get back to you soon.