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README.md
I2S Example
(See the README.md file in the upper level 'examples' directory for more information about examples.)
In this example, we generate a 100Hz triangle and sine wave and send it out from left and right channels at a sample rate of 36kHz through the I2S bus.
How to Use Example
Hardware Required
- A development board with ESP32 SoC (e.g., ESP32-DevKitC, ESP-WROVER-KIT, etc.)
- A USB cable for power supply and programming
Configure the Project
make menuconfig
- Set serial port under Serial Flasher Options.
Build and Flash
Build the project and flash it to the board, then run monitor tool to view serial output:
make -j4 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:
Test bits=24 free mem=293780, written data=2880
I2S: DMA Malloc info, datalen=blocksize=480, dma_buf_count=6
I2S: PLL_D2: Req RATE: 36000, real rate: 37878.000, BITS: 24, CLKM: 11, BCK: 8, MCLK: 13837837.838, SCLK: 1818144.000000, diva: 64, divb: 36
Test bits=32 free mem=292336, written data=2880
I2S: DMA Malloc info, datalen=blocksize=480, dma_buf_count=6
I2S: PLL_D2: Req RATE: 36000, real rate: 36764.000, BITS: 32, CLKM: 17, BCK: 4, MCLK: 9216921.692, SCLK: 2352896.000000, diva: 64, divb: 23
Test bits=16 free mem=293772, written data=1440
I2S: DMA Malloc info, datalen=blocksize=240, dma_buf_count=6
I2S: PLL_D2: Req RATE: 36000, real rate: 36764.000, BITS: 16, CLKM: 17, BCK: 8, MCLK: 9216921.692, SCLK: 1176448.000000, diva: 64, divb: 23
If you have a logic analyzer, you can use a logic analyzer to grab online data. The following table describes the pins we use by default (Note that you can also use other pins for the same purpose).
pin name | function | gpio_num |
---|---|---|
WS | word select | GPIO_NUM_25 |
SCK | continuous serial clock | GPIO_NUM_26 |
SD | serial data | GPIO_NUM_22 |
Troubleshooting
-
Program upload failure
- Hardware connection is not correct: run
make 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.