Pi Pico WS2812 Driver

About

Simple Pi Pico driver for the C/C++ SDK to communicate with WS2812 LEDs. This driver is based on the pico-examples/pio/ws2812 by Raspberry Pi.

Quick start

The driver can be imported using a cmake script (similar to the pico-sdk).

Here is a simple quick start guide:

1. Setup the pico-sdk for your project
2. Clone this repository
3. Download pico_ws2812_driver_import.cmake and put it along with pico_sdk_import.cmake (in the root folder of your project)
4. Copy and fill this CMakeLists.txt template

cmake_minimum_required(VERSION 3.28)

set(PICO_SDK_PATH "YOUR/SDK/PATH")
#set(PICO_WS2812_DRIVER_PATH "YOUR/DRIVER/PATH")

# Pull in SDK
include(pico_sdk_import.cmake)
include(pico_ws2812_driver_import.cmake)

project(test C CXX ASM)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 17)

# Initialize the SDK
pico_sdk_init()
pico_ws2812_driver_init()

add_executable(test main.c)
target_link_libraries(test pico_stdlib ws2812)
pico_add_extra_outputs(test)

If you cloned the driver in the same directory as the pico-sdk, you don't need to set PICO_WS2812_DRIVER_PATH. Otherwise, uncomment the set directive and complete the path.

5. Import "ws2812.h" and use the driver in your code (see the test example)

Test example

After setting up your cmake project, you can test the driver. Here is simple example. Note that the used GPIO Pin is 23, which is the default pin on YD-RP2040 boards.

This is main.c:

#include <pico/time.h>
#include <math.h>
#include <ws2812.h>

float compute_brightness() {
    return powf(sinf((float) to_ms_since_boot(get_absolute_time()) / 2500.0f), 2.0f);
}

bool led_callback(repeating_timer_t *timer) {
    float brightness = compute_brightness();

    ws2812_set_rgb_float(timer->user_data, brightness, brightness * 0.5f, 0);
    return true;
}

int main(void) {
    repeating_timer_t timer;

    ws2812_inst_t *inst = ws2812_init(pio0, 0, WS2812_DEFAULT_PIN, WS2812_DEFAULT_BAUD_RATE, false);

    add_repeating_timer_ms(25, led_callback, inst, &timer);

    while (1) {
        tight_loop_contents();
    }
}