esp-idf/examples/peripherals/sigma_delta/sdm_led/README.md

Supported Targets	ESP32	ESP32-C3	ESP32-C6	ESP32-H2	ESP32-P4	ESP32-S2	ESP32-S3

Sigma Delta Modulation LED Example

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

This example uses the sigma-delta driver to generate modulated output on a GPIO. If you connect a LED or LCD backlight control to the output GPIO, you will see it slowly brightening and dimming.

How to use example

Hardware Required

• A development board with any supported Espressif SoC (e.g., ESP32-DevKitC, ESP-WROVER-KIT, etc.)
• A USB cable for Power supply and programming
• An LED and a resistor to limit the LED current. Connect them as below:

                                   330R            LED
EXAMPLE_SIGMA_DELTA_GPIO_NUM +----/\/\/\----+------|>|-----+ GND

Configure the project

You can change the GPIO number by EXAMPLE_SIGMA_DELTA_GPIO_NUM.

Build and Flash

Build the project and flash it to the board, then run the monitor tool to view the serial output:

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.

Example Output

Once the upload is complete and the board is reset, the program should start running. This is reported on the monitor as below:

...
I (245) cpu_start: Starting scheduler.
I (249) example: Install sigma delta channel
I (249) gpio: GPIO[0]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0
I (259) example: Enable sigma delta channel
I (259) example: Change duty cycle continuously

Immediately after that the LED should start brightening and dimming.

Troubleshooting

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