In the name of GOD

GAGHL_AVR_NEOPIXEL

A lightweight and fast WS2812B (NeoPixel) driver library for AVR microcontrollers

Designed for bare-metal AVR development using register-level code and precise bit-banging.

📦 Features

• ✅ Supports up to 85 WS2812B LEDs (configurable)
• ✅ Built-in rainbow() animation function
• ✅ Global brightness control
• ✅ Automatic display() after color/buffer updates
• ✅ Simple C-style API
• ✅ Customizable Port and Pin macros
• ✅ Optimized for 8MHz and 9.6MHz clock with inline assembly

📚 API Overview

Function	Parameters	Description
neopixel_init()	(void)	Initializes the LED port/pin and clears the LED buffer
neopixel_send()	uint8_t *data, uint8_t length	Sends raw data to the LED strip (used internally by display())
neopixel_display()	(void)	Sends the current buffer (neopixel_buffer) to the LED strip
neopixel_clear()	(void)	Sets all pixels in the buffer to black (off)
neopixel_setPixel()	uint8_t index, uint8_t r, uint8_t g, uint8_t b	Sets the RGB color of the pixel at given index
neopixel_setBrightness()	uint8_t brightness	Applies a global brightness scaling (0–255) to all pixel data
neopixel_rainbow()	uint8_t offset, uint8_t spacing	Fills the buffer with a rainbow gradient starting at offset
neopixel_shift()	int8_t amount	Shifts the LED buffer left/right by amount positions (circularly)

🚀 Getting Started

1. Add the files to your project

Copy these files into your AVR project:

• GAGHL_AVR_NEOPIXEL.c
• GAGHL_AVR_NEOPIXEL.h

2. Configuration

You can customize the following macros in the .c file:

#define LED_PORT PORTC
#define LED_DDR  DDRC
#define LED_PIN  0

3. Example 1

#define F_CPU 8000000UL

#include <avr/io.h>
#include <util/delay.h>
#include "GAGHL_AVR_NEOPIXEL.h"

int main(void) {
	neopixel_init();
	neopixel_setBrightness(255);

	while (1) {
		for (uint8_t i = 0; i < 10; i++) {
			neopixel_setPixel(i, 255, 0, 0); // Red
			_delay_ms(100);
			neopixel_display();
		}
		for (uint8_t i = 0; i < 10; i++) {
			neopixel_setPixel(i, 0, 255, 0); // Green
			_delay_ms(100);
			neopixel_display();
		}
		for (uint8_t i = 0; i < 10; i++) {
			neopixel_setPixel(i, 0, 0, 255); // Blue
			_delay_ms(100);
			neopixel_display();
		}
	}
}

3. Example 2

#define F_CPU 8000000UL

#include <avr/io.h>
#include <util/delay.h>
#include "GAGHL_AVR_NEOPIXEL.h"

int main(void) {
	neopixel_init();
	neopixel_setBrightness(255);

	while (1) {
		for(uint8_t i = 0 ; i < 255 ; i++){
			neopixel_rainbow(i, 0);
			neopixel_display();
			_delay_ms(10);
			neopixel_setBrightness(20);
		}
	}
}

Wiring

MCU PIN -----------------> DIN on first WS2812B
+5V ---------------------> VCC
GND ---------------------> GND

⚠️ Make sure you use a 100nF capacitor near the LED and optionally a resistor (≈330Ω) in series with the DIN line

🤝 Contributing

Contributions are welcome!
Whether it's bug fixes, feature suggestions, or improvements — your help is appreciated.

• Fork the repository
• Create a new branch (git checkout -b feature/my-feature)
• Commit your changes (git commit -am 'Add new feature')
• Push to the branch (git push origin feature/my-feature)
• Open a Pull Request

If you’re using this library in your project, feel free to let me know — I’d love to check it out!

License

This project is licensed under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0).

You are free to:

• Share — copy and redistribute the material in any medium or format
• Adapt — remix, transform, and build upon the material

Under the following terms:

• Attribution — You must give appropriate credit to the author (GAGHL).
• NonCommercial — You may not use the material for commercial purposes without explicit permission.

For more information, see the full license: https://creativecommons.org/licenses/by-nc/4.0/

© 2025 GAGHL. All rights reserved.

Author

Developed by GAGHL