ATmega328P driver library for WS2812/WS2812B LED strips. Features: not many. Includes tasty AVR assembly. Tested on an Arduino Uno with the WS2812B chip.
#define __AVR_ATmega32U4__
#include <avr/io.h>
#include <inttypes.h>
#include <stddef.h>
#define F_CPU 16000000UL
#include <util/delay.h>
#include "ws2812b.h"
#define DELAY_US 10000
#define DATA_PIN 0
#define PIXELS 30
int main ()
{
ws2812b_setup_pin(DATA_PIN);
_delay_us(DELAY_US);
pixel buf[PIXELS] = { 0 };
const size_t pixels = sizeof(buf) / sizeof(pixel);
// clear any pixels by sending empty buffer
ws2812b_send_pixels(DATA_PIN, buf, pixels);
const pixel red = { .r = 0xFF, .g = 0x00, .b = 0x00 };
buf[0] = red;
ws2812b_initialize_pixel_buf(buf, pixels, red);
while(1) {
// shift all pixels one right for visual effect
pixel last = buf[pixels - 1];
for (size_t i = pixels - 1; i > 0; i--) {
buf[i] = buf[i - 1];
}
buf[0] = last;
// transmit our pixel buffer to the LED strip
ws2812b_send_pixels(DATA_PIN, buf, pixels);
// wait 10ms
_delay_us(DELAY_US);
}
}🐧: gcc-avr, avr-libc, binutils, avrdude, cmake
🍎: avr-gcc, avr-binutils, avrdude, cmake (install via Homebrew)
All: Check and adjust the
avrdudeport and programmer arguments before executingrun.sh.
Linux users: You may need to modify
build.shandrun.shso that the-DCMAKE_TOOLCHAIN_FILEargument reflects the full path to theavr.cmakefile.
Run build.sh to build. Run run.sh to build and upload with avrdude.
For more on how to transmit data to the WS2812(B) LED strips, see cpldcpu's excellent analysis and his light_ws2812 library, which applies broadly the same approach as the above and works for many more platforms.
The datasheets for the WS2812 and WS2812B chips are available here:
For more on the AVR assembly language and how to incorporate it into C with the GNU C compiler for AVR: