#include "mbed.h"
 
// SPST Pushbutton demo using internal PullDown function
// no external pull-down resistor needed
// Connect pushbutton from P8 to VOUT (VDD)
// Connect P21 to an LED
 
DigitalOut myled1(LED1);         //LEDs for display
DigitalOut myled2(LED2);
DigitalOut myled3(LED3);
DigitalOut myled4(LED4);
DigitalIn pb(p8);                //A pin to connect to a button
PwmOut variableled(p21);         //A modulated pin for a variable brighness LED 

void turnOn (int led);           //Function prototypes
void turnOff (int led);

int main() {
    pb.mode(PullDown);           //Set button to PullDown mode
    int led = 1;                 //Start with LED1
    while(1) {
        if (pb){                 //Button pressed
          turnOn(led);           //Turn the current LED on
          variableled = 1.0/led; //Set the brightness of the variable LED
          wait(0.1);             //Allow 0.1 sec for button debounce
          while (pb);            //Wait until button not pressed
          turnOff(led);          //Turn off the LED
          variableled = 0.0;     //Turn off variable LED
          wait(0.1);             //Allow 0.1 sec for button debounce
          {if (led == 4) led = 1; else led++;} //Cycle back to LED1
       }
    }
}
    void turnOn (int led) {         //Turns on the specified LED
      switch (led) {
        case 1 : myled1 = 1; break;
        case 2 : myled2 = 1; break;
        case 3 : myled3 = 1; break;
        case 4 : myled4 = 1; break;
      }
    }
    void turnOff (int led) {        //Turns off the specified LED
      switch (led) {
        case 1 : myled1 = 0; break;
        case 2 : myled2 = 0; break;
        case 3 : myled3 = 0; break;
        case 4 : myled4 = 0; break;
      }
    }