WS2812 NeoPixel Library

RP2040 library for controlling strips/pixels using WS2812 (NeoPixel) LEDs using PIO and pico-sdk

I wanted a library for use with the WS2812 (NeoPixel) on the RP2040 that didn't rely on Arduino.h or any other AVR include file. So I created this library using the pico-examples, the Adafruit NeoPixel library and some other RP2040 sources as reference.

1. Importing the library

• Clone this project into your pico project
• Add this to your CMakeLists.txt

    add_subdirectory(pico-ws2818)
  
    target_link_libraries(${PROJECT_NAME}
        pico_ws2818
    )

  • Import library in your code

  #include "pico-ws2812/ws2812.h"

  • Define your IO and create the class instance in your code

  const uint NEOPIXELIO = 10; // Define your GPIO pin
  const int NUMNEOPIXELS = 279; // Define number of neopixels
  
  WS2812 neopixel = WS2812(NUMNEOPIXELS, NEOPIXELIO); // Create your instance of the library

  • Alternatively you can also specify the statemachine and pio manually

  const uint NEOPIXELIO = 10; // Define your GPIO pin
  const int NUMNEOPIXELS = 279; // Define number of neopixels
  PIO pio = pio0;
  int sm = 1;
  
  WS2812 neopixel = WS2812(NUMNEOPIXELS, NEOPIXELIO, pio0, sm); // Create your instance of the library

2. Basic usage

void init()
{
  // Initialize the Neopixel (this starts the PIO program)
  neopixel.begin();
}

void loop()
{
  // Fill all the pixels with same value
  neopixel.fillPixelColor(0,0,255);
  neopixel.show();

  // wait 500ms
  sleep_ms(500);

  // Clear the entire string
  neopixel.clear();
  neopixel.show();
}

3. Functions in library

Two different constructors are available for use

WS2812(uint16_t num, uint8_t pin, PIO pio, int sm); // Basic Constructor

WS2812(uint16_t num, uint8_t pin); // This constructor tries to autoselect pio and sm

Various functions for controlling LEDs

neopixel.begin(); // Initialize the class instance after calling constructor

neopixel.show(); // Display all the pixels in the buffer

neopixel.setPixelColor(uint16_t led, uint8_t red, uint8_t green, uint8_t blue); // Set a NeoPixel to a given color.

neopixel.setPixelColor(uint16_t led, uint32_t color); // set a pixel color fomr 'packed' 32-bit RGB value

neopixel.clear(); // Clear the entire string

neopixel.fillPixelColor(uint8_t red, uint8_t green, uint8_t blue); // Fill all the pixels with same value

neopixel.updateLength(uint16_t num); // Change strand length
    
neopixel.numPixels(); // Returns the number of pixels currently connected
    
neopixel.getPixelColor(uint16_t led); // Query color from previously-set pixel