Skip to content

Latest commit

 

History

History
36 lines (23 loc) · 1.81 KB

README.md

File metadata and controls

36 lines (23 loc) · 1.81 KB

WS28xx RGB LED SPI Driver

This crate is a driver for WS28XX (WS2811, WS2812, WS2812B, WS2818) RGB LED chains/strips.

About this driver

This driver was developed for a specific project where each LED module along a chain had 9 single-colour LED modules, and no available neopixel-esque driver seemed up to the task. Therefore this library can support arbitrary module sizes and doesn't reference RGB.

This driver only works on Linux systems with a SPI device, like Raspberry Pi [1]. This is needed because my driver operates at 15.6MHz. This is required because I need to reach specific timings in nanoseconds according to the specification while sending data [2]. WS28xx LEDs use a one wire protocol without a clock, therefore the timings during data transmission are important.

The SPI device in your Raspberry Pi has a reliable clock with high frequencies available. Regular GPIO pins won't work! Toggling GPIO pins takes 1µs (in my testing) which is WAY TOO SLOW! Therefore I use SPI. There is a clock device in hardware - much more reliable!

Find the MOSI-Pin on your device (e.g. Raspberry Pi) and connect it with DIN-Port of the LED. That's all what's needed.

There is no warranty that this will work on your setup! High frequency stuff is complicated!

demo

Demo using a 8x8 RGB LED matrix. DIN is connected with MOSI (SPI Out Port).

Examples

See https://github.com/phip1611/ws2818-rgb-led-spi-driver/tree/master/examples.

Cargo.toml

[dependencies]
ws2818-rgb-led-spi-driver = "<latest version>"
# or if you need no_std
ws2818-rgb-led-spi-driver = { version = "<latest version>", default-features = false }
Links

[1] https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md
[2] https://cdn-shop.adafruit.com/datasheets/WS2812.pdf