/*Init the GPIO pin for interrupt control */
void GPIO_Init(){
    LPC_IOCON-> =..              //Pin configuration register
    LPC_GPIO1->FIODIR = ...      //GPIO Data direction register
    LPC_GPIO1->FIOMASK = ..      //GPIO Data mask register - choose  the right pin
    LPC_GPIO1->GPIOnIE = ..      //Set up falling or rising edge
    NVIC_EnableIRQ(PIO_1);       //Call API to enable interrupt in NVIC
    NVIC_SetPriority(PriorityN); //Set priority if needed
}


/*Must have the same name as listed in start-up file startup_LPC11xx.s */
void PIOINT1_IRQHandler(void){
   //Do something here
}

// in file mygpio.h or mygpio.c

#define MY_GPIO_IRQHandler PIOINT1_IRQHandler