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 ESP8266 SoC (e.g., ESP8266-DevKitC, 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=78188, written data=2880
I (5655) i2s: DMA Malloc info, datalen=blocksize=480, dma_buf_count=6
Test bits=16 free mem=78188, written data=1440
I (10735) i2s: DMA Malloc info, datalen=blocksize=240, dma_buf_count=6
Test bits=24 free mem=78188, written data=2880
I (15835) i2s: DMA Malloc info, datalen=blocksize=480, dma_buf_count=6
Test bits=16 free mem=78188, written data=1440
I (20915) i2s: DMA Malloc info, datalen=blocksize=240, dma_buf_count=6
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 |
|---|---|---|
| MCLK | main clock | GPIO_NUM_4 |
| WS | word select | GPIO_NUM_2 |
| SCK | continuous serial clock | GPIO_NUM_15 |
| SD | serial data | GPIO_NUM_3 |
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
menuconfigmenu, 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.