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CMakeLists.txt | ||
README.md | ||
pytest_i2s_record.py |
README.md
Supported Targets | ESP32 | ESP32-S3 |
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I2S Digital Microphone Recording Example
(See the README.md file in the upper level 'examples' directory for more information about examples.)
In this example, we record a sample audio file captured from the digital MEMS microphone on the I2S peripheral using PDM data format.
The audio is recorded into the SDCard using WAVE file format.
Audio Setting | Value |
---|---|
Sample Rate | 44100 Hz |
Bits per Sample | 16 bits |
How to Use Example
Hardware Required
- A development board with ESP32 or ESP32S3 SoC (e.g., ESP32-DevKitC, ESP-WROVER-KIT, etc.)
- A USB cable for power supply and programming
- A digital microphone (SPK0838HT4H PDM output was used in this example)
The digital PDM microphone is connected on the I2S interface I2S_NUM_0
.
The default GPIO configuration is the following:
Mic | GPIO |
---|---|
PDM Clock | GPIO4 |
PDM Data | GPIO5 |
The SDCard is connected using SPI peripheral.
SPI | SDCard | GPIO |
---|---|---|
MISO | DAT0 | GPIO17 |
MOSI | CMD | GPIO16 |
SCLK | CLK | GPIO18 |
CS | CD | GPIO19 |
To change the GPIO configuration, see the Example Configuration
from the menuconfig.
Configure the Project
idf.py menuconfig
In the Example Configuration
menu:
- Use
SDCard Configuration
to assign the SPI peripheral GPIOs. - Use
I2S MEMS MIC Configuration
to assign the I2S peripheral GPIOs and audio settings.
Optional: If you need, change the other options according to your requirements.
Build and Flash
Build the project and flash it to the board, then run monitor tool to view serial output:
idf.py -p PORT flash monitor
(To exit the serial monitor, type Ctrl-]
.)
See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
Example Output
Running this example, you will see the Bits per Sample changes every 5 seconds after you have run this example. You can use i2s_set_clk
to change the Bits per Sample and the Sample Rate. The output log can be seen below:
I (361) pdm_rec_example: PDM microphone recording Example start
I (371) I2S: DMA Malloc info, datalen=blocksize=2048, dma_desc_num=64
I (401) I2S: APLL: Req RATE: 44100, real rate: 88199.977, BITS: 16, CLKM: 1, BCK_M: 8, MCLK: 22579194.000, SCLK: 2822399.250000, diva: 1, divb: 0
I (431) I2S: APLL: Req RATE: 44100, real rate: 88199.977, BITS: 16, CLKM: 1, BCK_M: 8, MCLK: 22579194.000, SCLK: 2822399.250000, diva: 1, divb: 0
I (431) pdm_rec_example: Initializing SD card
I (431) pdm_rec_example: Using SDMMC peripheral
I (441) gpio: GPIO[13]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0
Name: USD
Type: SDHC/SDXC
Speed: 20 MHz
Size: 3813MB
I (481) pdm_rec_example: Starting recording for 60 seconds!
I (481) pdm_rec_example: Opening file
I (60451) pdm_rec_example: Recording done!
I (60471) pdm_rec_example: File written on SDCard
I (60471) pdm_rec_example: Card unmounted
Troubleshooting
-
Program upload failure
- Hardware connection is not correct: run
idf.py -p PORT monitor
, and reboot your board to see if there are any output logs. - The baud rate for downloading is too high: lower your baud rate in the
menuconfig
menu, and try again.
- Hardware connection is not correct: run
For any technical queries, please open an issue on GitHub. We will get back to you soon.