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