STM32 WS2812 LED Library

C++ Library for interfacing the WS2812 LEDs with a STM32 like the STM32F103C8 (BLUEPILL) using SysTick. Disclaimer: This library is far from perfect and everything but efficient. It just works.

Installation

Add the LED.cpp and the LED.hpp to your source / include folder

Basic Usage

Before you start: The Library should work with any of the GPIO Pins. Make sure to initialize the GPIO that you want to use in GPIO FAST MODE. Moreover, set the internal clock frequency to 72MHz.

To use the LED library follow the steps.

1. Include the Library with

#include "LED.hpp"

2. Specify the number of LEDs in the LED.hpp file

static const uint8_t _neoLEDS = 8;

3. Create a new LED object in your code, e.g.

LED led = LED();

If you want to use the implemented animation functions you need to supply some kind of clock with a Hardware Timer or simply by using the main. See the next chapter for more information.

4. Use the implemented functions, e.g.

led.setAllNeopixels(0xFF, 0x00, 0x00);

Usage of Animations

Using animations requires you to count up a number in a fixed interval of your choice. This number is used by the led functions to refresh / update the animation. Example: Using the animateSine function with htim2:

1. Configure and start a hardware timer of your choice, e.g htim2: The STM32F103C8T6 can run with 72MHz. Using a prescaler of 14400 - 1 yields a tick frequency of 5kHz.
2. In the main, we call the animateSine function every 10 Timer ticks (=500Hz refresh rate) to increase the _updateCount

uint8_t color[3] = {128, 0, 0};
if(TIM2->CNT >= 10)
{
	led._updateCNT++;
	TIM2->CNT = 0;
	led.animateSine(color, 0.02, 220, 0.8);
}

The following code should result in a red SineWave pattern on the LED strip.

2. Alternative: If your code allows it, you could simply increase the count in a loop with HAL_Delay

uint8_t color[3] = {128, 0, 0};
while(1) 
{
	led._updateCNT++;
	led.animateSine(color, 0.02, 220, 0.8);
	HAL_Delay(2);
}