Timer0 with delay function

Hi,

I am using MCB2300 board with LPC2387.
I want to toggle my LEDs with delay from 20 to 30 microsecond.
I found function for delay in millisecond and microsecond from its sample code.
below is the function for microsecond.

 void delayus(BYTE timer_num, DWORD delayInus)
{
  if ( timer_num == 0 )
  {
        /*
        * setup timer #0 for delay
        */
        T0TCR = 0x02;           /* reset timer */
        T0PR  = 0x00;           /* set prescaler to zero */
        T0MR0 = delayInus * (Fpclk - 1);
        T0IR  = 0xff;           /* reset all interrrupts */
        T0MCR = 0x04;           /* stop timer on match */
        T0TCR = 0x01;           /* start timer */

        /* wait until delay time has elapsed */
        while (T0TCR & 0x01);
  }

Below is the function of millisecond.

void delayMs(BYTE timer_num, DWORD delayInMs)
{
  if ( timer_num == 0 )
  {
        /*
        * setup timer #0 for delay
        */
        T0TCR = 0x02;           /* reset timer */
        T0PR  = 0x00;           /* set prescaler to zero */
        T0MR0 = delayInMs * (Fpclk / 1000-1);
        T0IR  = 0xff;           /* reset all interrrupts */
        T0MCR = 0x04;           /* stop timer on match */
        T0TCR = 0x01;           /* start timer */

        /* wait until delay time has elapsed */
        while (T0TCR & 0x01);
  }

the problem is when I use delay function of Microsecond in main function for delay, I write delayus(0,20) for delay of 20 Microsecond
But led blinks at every 20 seconds instead of every 20 Microsecond.

So I think this function is work for delay of second not for Microsecond.

while the function of Millisecond is working properly.

So let me know am i doing something wrong?

Thanks