File content as of revision 5:08c6b4ca686a:

#include "mbed.h"
#include "C12832.h"

Timer t;
 int count;
 int actualCount;
 float time;
 int timeSwitch;
DigitalOut myled(LED1);
DigitalOut myled2(LED2);
InterruptIn Hallsensor(p5);
DigitalIn button(p14);

C12832 lcd(p5, p7, p6, p8, p11);
void pulses() {
    if(myled == 1) {
        myled = 0;
    } else {
        myled = 1;
    }
    count++;
    
}
int main() {
  while(1){
      if(button){
       timeSwitch=timeSwitch+1;
       
       
       }
       
         switch(timeSwitch) {
             case 1: {
                 
                  lcd.cls();
    lcd.printf("start");
       Hallsensor.rise(&pulses);
      
        t.reset();
        t.start();
        
        
        }
        
        case 2: {
            
             lcd.cls();
    lcd.printf("stop");
            
             t.stop();
          
       actualCount=count/2;
       time= t.read()/actualCount;
          
            
            }
            
    case 3:{
         
          lcd.cls();
    lcd.printf("reset");
         t.reset();
         timeSwitch=0;
         
         count=0;
         actualCount=0;
         
         
        
        
        }
        
              }
        
      
      }
     
 
 
 
 }