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esp-idf/examples/peripherals/sigma_delta/sdm_dac
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pytest_sdm_dac_example.py sdm: add wave output example 2023-01-06 17:01:48 +08:00
README.md sdm: add wave output example 2023-01-06 17:01:48 +08:00

README.md

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

Sigma Delta Modulation DAC 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 filter the output signal with an active or passive filter, you can get a 1 KHz sine wave.

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 active or passive filter. Connect them as below:
┌──────────────────────────────┐
│             ESP              │     ┌───────────────────┐
│                              │     │ Active or Passive │    Sine Wave
│ EXAMPLE_SIGMA_DELTA_GPIO_NUM ├────►│      Filter       ├──────────────
└──────────────────────────────┘     └───────────────────┘

Configure the project

The main configurations can be update by the macro that defined at the top of the example source file, including the output gpio, timer callback interval and the sine wave frequency and amplitude.

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 (299) main_task: Calling app_main()
I (309) gpio: GPIO[0]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0
I (309) sdm_dac: Sigma-delta output is attached to GPIO 0
I (319) sdm_dac: Timer allocated with resolution 10000000 Hz
I (329) sdm_dac: Timer callback registered, interval 10 us
I (329) sdm_dac: Timer enabled
I (339) sdm_dac: Output start

After the output stated, you can monitor the sine wave after the filter by an oscilloscope.

output_wave

Troubleshooting

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