GPIO external interrupt on LPC1769
Your Interrupt handler is wrong, it should look like:

void EINT0_IRQHandler(void)
{
  LPC_SC-&gt;EXTINT = (1&lt;&lt;EINT0);
  //light LED here, do not try to use printf() inside interrupts
}


But the real culprit might be the GPIO pin 2.10 - which is also used to trigger the UART bootloader on startup when LOW. See in manual UM10360.pdf, chapter 32, describing ISP function. 

I recommend using external Interrupt 1 on P2.11 instead, which does not have this restriction.