LPC1768 - pulse counter not work

Hi, I have to count pulses by LPC1768. I try to use port P0.24 with 
function CAP3.1 to driving Timer3 as counter.

Example of timer3 configuration:

1

//   counter 3

2

   const unsigned long TCR_COUNT_RESET = 2, TCR_COUNT_ENABLE = 0x01;

3

   LPC_SC->PCONP |= (1 << 23);

4

   LPC_TIM3->TCR = TCR_COUNT_RESET;

5

   LPC_TIM3->CTCR = 0x101;

6

   LPC_TIM3->TCR = TCR_COUNT_ENABLE;

And port definition:

1

   LPC_PINCON->PINSEL1 |= (1 << 17) | (1 << 16); // set pin P0.24 as CAP3.1

2

   LPC_GPIO0->FIODIR &=~(1<<24);         // set pin P0.24 as input

And LPC_TIM3->TC not change.
If I configure Timer3 with PCLK as source is OK. When i use P0.24 as 
input pin is also ok. I can count level changes in main loop. But why 
not work counting pulses by timer/counter functionality?
Maybe I have to match any register more?

Regards