Page 130 - ARM Based Microcontroller Projects Using MBED

116 7. USING THE Mbed WITH SIMPLE PROJECTS

/***************************************************************************

RGB LED CONTROL
===============
In this project an RGB LED is connected to the Nucleo board. Additionally,
3 buttons named R,G, and B are conencted to the board. When a button is
pressed the corresponding colour is displayed by the RGB LED. Pressing the
same button again removes that colour from the display.
The buttons are pulled-up in software and are connected as follows:
R to PC_0
G to PC_1
B to PC_2
The RGB LED pins are connected as follows:
Red to PC_3
Green to PC_4
Blue to PC_5
Author: Dogan Ibrahim
Date : August 2018
File : RGB
*****************************************************************************/
#include "mbed.h"

BusOut RGB(PC_3, PC_4, PC_5); // Group the LED pins
DigitalIn R(PC_0, PullUp); // R button
DigitalIn G(PC_1, PullUp); // G button
DigitalIn B(PC_2, PullUp); // B button

int main()
{
RGB = 0; // LEDs OFF at beginning

while(1) // Do forever
{
if(R == 0) // If R pressed
{
if(RGB & 1 == 1) // If Red is active
RGB = RGB & 6; // Turn OFF Red
else // Otherwise
RGB = RGB | 1; // Turn ON Red
while(R == 0); // Wait until released
}
else if(G == 0) // If G pressed
{
if((RGB & 2) == 2) //If Green is active
RGB = RGB & 5; // Turn OFF Green
else // Otherwise
RGB = RGB | 2; // Turn ON Green
while(G == 0); // Wait until released
}
FIG. 7.59 Program listing.
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