ESP32 DLED Controller

Using the RMT peripheral of ESP32, controls WS2812 type digital LEDs: WS2812, WS2812B, WS2812C, WS2812D, WS2812S, WS2813 and WS2815. SK6812 should work with WS281x mode.

This implementation uses the RMT driver from ESP-IDF and uses one RMT channel for a LED strip leaving the other channels free, under the control of the RMT driver. Here are some key points of this implementation:

• the control of the LEDs is separated from the control of the RMT peripheral;
• the other RMT channels can be used as needed;
• the RMT peripheral is used through ESP-IDF's own driver.

Right now the negative point is that this code uses a lot of RAM, because of the way the driver and peripheral works. There is a way to add a hook in the driver's transmission code but considering the multithreading architecture of FreeRTOS this may add jitter creating visual artifacts, depending on application.

Breaking changes

DLEDController v2

• uses DStripData as input stream.
• DStrip class was obsoleted and removed.

See the example for simple usage.

About timings

Timings are from datasheets. According to Worldsemi's datasheets there are a few timings sets:

• one for WS2812
• one for WS2812B, WS2812C, WS2812S, WS2813 and WS2815
• one for WS2812D

In Tim's Blog (cpldcpu) are some interesting investigations about timings of various digital LEDs.

Dependencies

• Espressif IoT Development Framework
• ESP32RMT

Example code

In the example directory is an application that should control 64 Digital LEDs of WS2812 type, connected to the GPIO pin 14 through a non-inverting level converter.

Hardware details

The code ( with ESP32RMT ) was tested on the following boards:

• ESP32-DevKitC board with a level convertor made from two 74HCT1G04 inverters
• Dev33-DLED - uses SN74LV1T34 logic level shifter connected to an ESP32-WROOM-32 module
• Dev34-DLEDGrid - uses SN74LV1T34 logic level shifter connected to an ESP32-WROOM-32 module

and:

• a LED strip with 300 WS2812B digital LEDs + Mean Well EPS-65S-5 power source
• a 8x8 LED board with WS2812 digital LEDs + Sony VTC6 18650 Battery

Development Environment

Currently uses the latest stable version of Espressif IoT Development Framework, v4.1 as of December 2020.

Editing was done in Visual Studio Code.

Version control with Git.

License

This software and its documentation are released under the GNU GPLv3 License. See the LICENSE-GPLv3.txt file.

Note

This is a faster and more efficient version of the one published by me previously in the esp32_digitalLEDs repository.