README.md

GPIO LED Controller

This library is meant for controlling an RGB LED by switching the red, green and blue channel each with a seperate GPIO pin.

Usage

GPIO pins

Currently, the library assumes the following mapping between GPIO pins and RGB channels:

GPIO pin	Corresponding RGB channel
18	Red
23	Green
24	Blue

You can change the mapping by altering the PIN_RED, PIN_GREEN & PIN_BLUE macros inside src/led/led.c.

DMA channel

The library also assumes that the DMA channel 5 is usable and enabled. To change the DMA channel alter the DMA_CHANNEL macro inside src/led/led.c.

API

All high-level functions are declared in led/led.h, which are:

Function name	Description
startLED()	Must be called once in the program before using setRGB. Maps DMA & GPIO into memory and initializes the DMA.
stopLED()	Unmaps DMA & GPIO and frees allocated memory. Must be called before program exits.
setRGB(uint8_t red, uint8_t green, uint8_t blue)	Sets the current color.

Example

Here is a simple example to get you started:

#include <unistd.h> // for sleep()
#include "led/led.h"

int main(int argc, char* argv)
{
    startLED();

    for (unsigned int i = 0; i < 100; i++)
    {
        setRGB(255, 0 , 0);
        usleep(50000);
        setRGB(0, 255 , 0);
        usleep(50000);
        setRGB(0, 0 , 255);
        usleep(50000);
    }

    stopLED();

    return 0;
}

For more examples take a look at the examples folder.

Compiling

This is not a header-only library. You have to compile and link all the source files inside the src directory.