cAPA102 is a lightweight hardware SPI based APA102 library, fast and easy to use.

This library is targeting to Raspberry Pi, ReSpeaker Core V2, Beaglebone such platforms.

@brief: Initialise a set of apa102 LEDs

@param[in] led_num: Number of LEDs (0-255)
@param[in] spi_bus: SPI bus number (0-255)
@param[in] spi_dev: SPI device number (0-255)
@param[in] brightness: Global brightness (0-31)

@returns:  0\ Success
          -1\ Error

@brief: Change the global brightness and fresh

@param[in] brightness: New brightness value

@brief: Get the brightness

@return current brightness value (0-31)

@brief: Set color for a specific pixel by giving R, G and B value separately

@param[in] index: Index of the target led (0-255)
@param[in] red: Intensity of red colour (0-255)
@param[in] green: Intensity of green colour (0-255)
@param[in] blue: Intensity of blue colour (0-255)

@brief: Get colour form a specific pixel for R, G and B separately

@param[in] index: Index of the target led (0-255)
@param[out] red: Intensity of red colour (0-255)
@param[out] green: Intensity of green colour (0-255)
@param[out] blue: Intensity of blue colour (0-255)

@brief: Set color for a specific pixel by using 4byte date

@param[in] index: Index of the target led (0-255)
@param[in] red: Intensity of red colour (0-255)
@param[in] green: Intensity of green colour (0-255)
@param[in] blue: Intensity of blue colour (0-255)

@example: cAPA102_Get_Pixel_RGB(1, 0xFF0000) sets the 1st LED to red colour

@brief: Get colour form a specific pixel

@param[in] index: Index of the target led (0-255)

@returns: 32 bits colour data

@brief: Clear all the pixels

@brief: Refresh display (After modifying pixel colour)

@brief: Close SPI file, release memory

The following is an example of using this APA102 library with 12 LEDs.

1. Copy the cAPA102.h and cAPA102.c to your project folder.

2. Include the head file from where you would use this library.

#include "cAPA102.h"

3. Call cAPA102_Init(12, 0, 0, 31) function with the led_num is 12, spi0.0 and largest brightness to initialise the LED set.

cAPA102_Init(12, 0, 0, 31);

4. Call cAPA102_Set_Pixel_4byte() function to set the first 8 LEDs where the first 4 LEDs are red and the following 4 LEDs are green. Call cAPA102_Set_Pixel_RGB() function to set the second 8 LEDs where the first 4 LEDs are blue and the following 4 LEDs are cyan.

int i;
for ( i = 0; i < 3; i++)
    cAPA102_Set_Pixel_4byte(i, 0xFF0000);

for ( i = 3; i < 6; i++)
    cAPA102_Set_Pixel_4byte(i, 0x00FF00);

for ( i = 6; i < 9; i++)
    cAPA102_Set_Pixel_RGB(i, 0, 0, 255);

for ( i = 9; i < 12; i++)
    cAPA102_Set_Pixel_RGB(i, 255, 255, 0);

5. Call cAPA102_Refresh() function to refresh the LEDs.

cAPA102_Refresh();

6. [Important] Call cAPA102_Close() function to properly close SPI device file and release pixel memory

cAPA102_Close();

(All the pixels data are save by dynamically allocating memory space, without calling this function, your program will cause a memory leakage)

Contributions are welcome! Not familiar with the codebase yet? No problem!

There are many ways to contribute to open source projects: reporting bugs, helping with the documentation, spreading the word and of course, adding new features and patches.

• Make sure you have a GitHub account.
• Open a new issue, assuming one does not already exist.
• Clearly describe the issue including steps to reproduce when it is a bug.

• Fork this repository.
• Create a feature branch from where you want to base your work.
• Make commits of logical units (if needed rebase your feature branch before submitting it).
• Check for unnecessary whitespace with git diff --check before committing.
• Make sure your commit messages are well formatted.
• If your commit fixes an open issue, reference it in the commit message (f.e. #15).
• Run all the tests (if existing) to assure nothing else was accidentally broken.

These guidelines also apply when helping with documentation.

• Push your changes to a feature branch in your fork of the repository.
• Submit a Pull Request.
• Wait for maintainer feedback.