Invoke gcc compiler. -o means to generate files, and will be followed by the name of generated

file. rgb_effect.c is source program, and -lwiringPi means to use the wiringPi library in

Raspberry Pi.

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Run the programs

./rgb_effect

Three RGB LEDs display breathing effect in purple at the same time.

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Code Analysis

1. There are three RGB LEDs on the board, so define the number of LEDs as 3. Define the register

address: RGB_Effect is 0x04, RGB_Speed is 0x05, RGB_Color is 0x06. Declare the necessary

functions.

2. void setRGB(int num, int R, int G, int B) function:

Set RGB LED color. num refers to the LED number: o is the first LED, 1 for the second LED, 2

for the third one. When num is over 3, it means to set all the LEDs. The range of R, G, B is

0~255.