File content as of revision 2:e26c096f1946:

#include "Timer.h"
//This class uses Timer 1

// static data initialization  (only called once)
bool Timer::timer1initialized = false; 
int Timer::resolution = 1000000;

void Timer::initTimer1(int res) //microseconds accuracy
{
    uint8_t pclk;
    uint32_t pclkdiv = (LPC_SC->PCLKSEL0 >> 4) & 0x03; //PCLK for Timer 1 (page 56)

    switch ( pclkdiv ) // table 42 (page 57 in user manual)
    {
      case 0x00:
      default:
            pclk = 4;
            break;
      case 0x01:
            pclk = 1;
            break;
      case 0x02:
            pclk = 2;
            break;
      case 0x03:
            pclk = 8;
            break;
    }

    LPC_TIM1->TCR = 0x02;           /* reset timer */
    LPC_TIM1->PR  = (SystemCoreClock / (pclk * res)); //default: microsecond steps
    LPC_TIM1->MR0 = 2147483647;             /* highest number a 32bit signed int can store (for us ~ 35.79 minutes, or, for ms ~ 596.52 hours ) */
    LPC_TIM1->IR  = 0xff;           /* reset all interrrupts */
    LPC_TIM1->MCR = 0x02;           /* reset timer on match */
    LPC_TIM1->TCR = 0x01;           /* start timer */

    /* The timer simply goes on forever! It just resets itself when it hits the max number for TC */
    timer1initialized = true;
    resolution = res;
}

Timer::Timer()
{        
    if(!timer1initialized)
    {
        initTimer1(resolution); //default resolution
    }
    
    starttime = 0;
    stoptime = 0;
    running = false;
}

//for when we want to allow lower counting resolution, eg. milliseconds
//so we can count longer than the 35 minutes with microsecond resolution
Timer::Timer(int res) // millisecond, res = 1000
{   
    if(!timer1initialized)
    {
        initTimer1(res); //custom resolution
    }
    
    starttime = 0;
    stoptime = 0;
    running = false;
}

void Timer::start()
{
    starttime = LPC_TIM1->TC;
    stoptime = 0; //clear previous stoptime
    running = true;
}

void Timer::stop()
{
   stoptime = LPC_TIM1->TC;
   running = false;
}

void Timer::reset()
{
    if(running)
    {
        starttime = LPC_TIM1->TC;
    }
    else
    {
        starttime = 0;
    }
    
    stoptime = 0;
}

float Timer::read()
{
    if(running)
    {    
        int currenttime = LPC_TIM1->TC;
        return (currenttime - starttime) / (resolution*1.0);
    }
    else // compare startime and stoptime
    {
        return (stoptime - starttime) / (resolution*1.0);
    }
}

Timer::operator float()
{
    return read();
}